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lmdb-erl/c_src/mdb.c
younes 6498e5a4e3 initial release
2012-09-30 19:42:44 +02:00

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/** @file mdb.c
* @brief memory-mapped database library
*
* A Btree-based database management library modeled loosely on the
* BerkeleyDB API, but much simplified.
*/
/*
* Copyright 2011-2012 Howard Chu, Symas Corp.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*
* This code is derived from btree.c written by Martin Hedenfalk.
*
* Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#ifdef _WIN32
#include <windows.h>
#else
#include <sys/uio.h>
#include <sys/mman.h>
#ifdef HAVE_SYS_FILE_H
#include <sys/file.h>
#endif
#include <fcntl.h>
#endif
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#if !(defined(BYTE_ORDER) || defined(__BYTE_ORDER))
#include <resolv.h> /* defines BYTE_ORDER on HPUX and Solaris */
#endif
#if defined(__APPLE__) || defined (BSD)
# define MDB_USE_POSIX_SEM 1
# define MDB_FDATASYNC fsync
#elif defined(ANDROID)
# define MDB_FDATASYNC fsync
#endif
#ifndef _WIN32
#include <pthread.h>
#ifdef MDB_USE_POSIX_SEM
#include <semaphore.h>
#endif
#endif
#ifdef USE_VALGRIND
#include <valgrind/memcheck.h>
#define VGMEMP_CREATE(h,r,z) VALGRIND_CREATE_MEMPOOL(h,r,z)
#define VGMEMP_ALLOC(h,a,s) VALGRIND_MEMPOOL_ALLOC(h,a,s)
#define VGMEMP_FREE(h,a) VALGRIND_MEMPOOL_FREE(h,a)
#define VGMEMP_DESTROY(h) VALGRIND_DESTROY_MEMPOOL(h)
#define VGMEMP_DEFINED(a,s) VALGRIND_MAKE_MEM_DEFINED(a,s)
#else
#define VGMEMP_CREATE(h,r,z)
#define VGMEMP_ALLOC(h,a,s)
#define VGMEMP_FREE(h,a)
#define VGMEMP_DESTROY(h)
#define VGMEMP_DEFINED(a,s)
#endif
#ifndef BYTE_ORDER
# if (defined(_LITTLE_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN))
/* Solaris just defines one or the other */
# define LITTLE_ENDIAN 1234
# define BIG_ENDIAN 4321
# ifdef _LITTLE_ENDIAN
# define BYTE_ORDER LITTLE_ENDIAN
# else
# define BYTE_ORDER BIG_ENDIAN
# endif
# else
# define BYTE_ORDER __BYTE_ORDER
# endif
#endif
#ifndef LITTLE_ENDIAN
#define LITTLE_ENDIAN __LITTLE_ENDIAN
#endif
#ifndef BIG_ENDIAN
#define BIG_ENDIAN __BIG_ENDIAN
#endif
#if defined(__i386) || defined(__x86_64)
#define MISALIGNED_OK 1
#endif
#include "mdb.h"
#include "midl.h"
#if (BYTE_ORDER == LITTLE_ENDIAN) == (BYTE_ORDER == BIG_ENDIAN)
# error "Unknown or unsupported endianness (BYTE_ORDER)"
#elif (-6 & 5) || CHAR_BIT != 8 || UINT_MAX < 0xffffffff || ULONG_MAX % 0xFFFF
# error "Two's complement, reasonably sized integer types, please"
#endif
/** @defgroup internal MDB Internals
* @{
*/
/** @defgroup compat Windows Compatibility Macros
* A bunch of macros to minimize the amount of platform-specific ifdefs
* needed throughout the rest of the code. When the features this library
* needs are similar enough to POSIX to be hidden in a one-or-two line
* replacement, this macro approach is used.
* @{
*/
#ifdef _WIN32
#define pthread_t DWORD
#define pthread_mutex_t HANDLE
#define pthread_key_t DWORD
#define pthread_self() GetCurrentThreadId()
#define pthread_key_create(x,y) (*(x) = TlsAlloc())
#define pthread_key_delete(x) TlsFree(x)
#define pthread_getspecific(x) TlsGetValue(x)
#define pthread_setspecific(x,y) TlsSetValue(x,y)
#define pthread_mutex_unlock(x) ReleaseMutex(x)
#define pthread_mutex_lock(x) WaitForSingleObject(x, INFINITE)
#define LOCK_MUTEX_R(env) pthread_mutex_lock((env)->me_rmutex)
#define UNLOCK_MUTEX_R(env) pthread_mutex_unlock((env)->me_rmutex)
#define LOCK_MUTEX_W(env) pthread_mutex_lock((env)->me_wmutex)
#define UNLOCK_MUTEX_W(env) pthread_mutex_unlock((env)->me_wmutex)
#define getpid() GetCurrentProcessId()
#define MDB_FDATASYNC(fd) (!FlushFileBuffers(fd))
#define MDB_MSYNC(addr,len,flags) (!FlushViewOfFile(addr,len))
#define ErrCode() GetLastError()
#define GET_PAGESIZE(x) {SYSTEM_INFO si; GetSystemInfo(&si); (x) = si.dwPageSize;}
#define close(fd) CloseHandle(fd)
#define munmap(ptr,len) UnmapViewOfFile(ptr)
#else
#ifdef MDB_USE_POSIX_SEM
#define LOCK_MUTEX_R(env) mdb_sem_wait((env)->me_rmutex)
#define UNLOCK_MUTEX_R(env) sem_post((env)->me_rmutex)
#define LOCK_MUTEX_W(env) mdb_sem_wait((env)->me_wmutex)
#define UNLOCK_MUTEX_W(env) sem_post((env)->me_wmutex)
static int
mdb_sem_wait(sem_t *sem)
{
int rc;
while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;
return rc;
}
#else
/** Lock the reader mutex.
*/
#define LOCK_MUTEX_R(env) pthread_mutex_lock(&(env)->me_txns->mti_mutex)
/** Unlock the reader mutex.
*/
#define UNLOCK_MUTEX_R(env) pthread_mutex_unlock(&(env)->me_txns->mti_mutex)
/** Lock the writer mutex.
* Only a single write transaction is allowed at a time. Other writers
* will block waiting for this mutex.
*/
#define LOCK_MUTEX_W(env) pthread_mutex_lock(&(env)->me_txns->mti_wmutex)
/** Unlock the writer mutex.
*/
#define UNLOCK_MUTEX_W(env) pthread_mutex_unlock(&(env)->me_txns->mti_wmutex)
#endif /* MDB_USE_POSIX_SEM */
/** Get the error code for the last failed system function.
*/
#define ErrCode() errno
/** An abstraction for a file handle.
* On POSIX systems file handles are small integers. On Windows
* they're opaque pointers.
*/
#define HANDLE int
/** A value for an invalid file handle.
* Mainly used to initialize file variables and signify that they are
* unused.
*/
#define INVALID_HANDLE_VALUE (-1)
/** Get the size of a memory page for the system.
* This is the basic size that the platform's memory manager uses, and is
* fundamental to the use of memory-mapped files.
*/
#define GET_PAGESIZE(x) ((x) = sysconf(_SC_PAGE_SIZE))
#endif
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
#define MNAME_LEN 32
#else
#define MNAME_LEN (sizeof(pthread_mutex_t))
#endif
/** @} */
#ifndef _WIN32
/** A flag for opening a file and requesting synchronous data writes.
* This is only used when writing a meta page. It's not strictly needed;
* we could just do a normal write and then immediately perform a flush.
* But if this flag is available it saves us an extra system call.
*
* @note If O_DSYNC is undefined but exists in /usr/include,
* preferably set some compiler flag to get the definition.
* Otherwise compile with the less efficient -DMDB_DSYNC=O_SYNC.
*/
#ifndef MDB_DSYNC
# define MDB_DSYNC O_DSYNC
#endif
#endif
/** Function for flushing the data of a file. Define this to fsync
* if fdatasync() is not supported.
*/
#ifndef MDB_FDATASYNC
# define MDB_FDATASYNC fdatasync
#endif
#ifndef MDB_MSYNC
# define MDB_MSYNC(addr,len,flags) msync(addr,len,flags)
#endif
#ifndef MS_SYNC
#define MS_SYNC 1
#endif
#ifndef MS_ASYNC
#define MS_ASYNC 0
#endif
/** A page number in the database.
* Note that 64 bit page numbers are overkill, since pages themselves
* already represent 12-13 bits of addressable memory, and the OS will
* always limit applications to a maximum of 63 bits of address space.
*
* @note In the #MDB_node structure, we only store 48 bits of this value,
* which thus limits us to only 60 bits of addressable data.
*/
typedef MDB_ID pgno_t;
/** A transaction ID.
* See struct MDB_txn.mt_txnid for details.
*/
typedef MDB_ID txnid_t;
/** @defgroup debug Debug Macros
* @{
*/
#ifndef MDB_DEBUG
/** Enable debug output.
* Set this to 1 for copious tracing. Set to 2 to add dumps of all IDLs
* read from and written to the database (used for free space management).
*/
#define MDB_DEBUG 0
#endif
#if !(__STDC_VERSION__ >= 199901L || defined(__GNUC__))
# define DPRINTF (void) /* Vararg macros may be unsupported */
#elif MDB_DEBUG
static int mdb_debug;
static txnid_t mdb_debug_start;
/** Print a debug message with printf formatting. */
# define DPRINTF(fmt, ...) /**< Requires 2 or more args */ \
((void) ((mdb_debug) && \
fprintf(stderr, "%s:%d " fmt "\n", __func__, __LINE__, __VA_ARGS__)))
#else
# define DPRINTF(fmt, ...) ((void) 0)
#endif
/** Print a debug string.
* The string is printed literally, with no format processing.
*/
#define DPUTS(arg) DPRINTF("%s", arg)
/** @} */
/** A default memory page size.
* The actual size is platform-dependent, but we use this for
* boot-strapping. We probably should not be using this any more.
* The #GET_PAGESIZE() macro is used to get the actual size.
*
* Note that we don't currently support Huge pages. On Linux,
* regular data files cannot use Huge pages, and in general
* Huge pages aren't actually pageable. We rely on the OS
* demand-pager to read our data and page it out when memory
* pressure from other processes is high. So until OSs have
* actual paging support for Huge pages, they're not viable.
*/
#define MDB_PAGESIZE 4096
/** The minimum number of keys required in a database page.
* Setting this to a larger value will place a smaller bound on the
* maximum size of a data item. Data items larger than this size will
* be pushed into overflow pages instead of being stored directly in
* the B-tree node. This value used to default to 4. With a page size
* of 4096 bytes that meant that any item larger than 1024 bytes would
* go into an overflow page. That also meant that on average 2-3KB of
* each overflow page was wasted space. The value cannot be lower than
* 2 because then there would no longer be a tree structure. With this
* value, items larger than 2KB will go into overflow pages, and on
* average only 1KB will be wasted.
*/
#define MDB_MINKEYS 2
/** A stamp that identifies a file as an MDB file.
* There's nothing special about this value other than that it is easily
* recognizable, and it will reflect any byte order mismatches.
*/
#define MDB_MAGIC 0xBEEFC0DE
/** The version number for a database's file format. */
#define MDB_VERSION 1
/** The maximum size of a key in the database.
* While data items have essentially unbounded size, we require that
* keys all fit onto a regular page. This limit could be raised a bit
* further if needed; to something just under #MDB_PAGESIZE / #MDB_MINKEYS.
*/
#define MAXKEYSIZE 511
#if MDB_DEBUG
/** A key buffer.
* @ingroup debug
* This is used for printing a hex dump of a key's contents.
*/
#define DKBUF char kbuf[(MAXKEYSIZE*2+1)]
/** Display a key in hex.
* @ingroup debug
* Invoke a function to display a key in hex.
*/
#define DKEY(x) mdb_dkey(x, kbuf)
#else
#define DKBUF typedef int dummy_kbuf /* so we can put ';' after */
#define DKEY(x) 0
#endif
/** An invalid page number.
* Mainly used to denote an empty tree.
*/
#define P_INVALID (~(pgno_t)0)
/** Test if a flag \b f is set in a flag word \b w. */
#define F_ISSET(w, f) (((w) & (f)) == (f))
/** Used for offsets within a single page.
* Since memory pages are typically 4 or 8KB in size, 12-13 bits,
* this is plenty.
*/
typedef uint16_t indx_t;
/** Default size of memory map.
* This is certainly too small for any actual applications. Apps should always set
* the size explicitly using #mdb_env_set_mapsize().
*/
#define DEFAULT_MAPSIZE 1048576
/** @defgroup readers Reader Lock Table
* Readers don't acquire any locks for their data access. Instead, they
* simply record their transaction ID in the reader table. The reader
* mutex is needed just to find an empty slot in the reader table. The
* slot's address is saved in thread-specific data so that subsequent read
* transactions started by the same thread need no further locking to proceed.
*
* Since the database uses multi-version concurrency control, readers don't
* actually need any locking. This table is used to keep track of which
* readers are using data from which old transactions, so that we'll know
* when a particular old transaction is no longer in use. Old transactions
* that have discarded any data pages can then have those pages reclaimed
* for use by a later write transaction.
*
* The lock table is constructed such that reader slots are aligned with the
* processor's cache line size. Any slot is only ever used by one thread.
* This alignment guarantees that there will be no contention or cache
* thrashing as threads update their own slot info, and also eliminates
* any need for locking when accessing a slot.
*
* A writer thread will scan every slot in the table to determine the oldest
* outstanding reader transaction. Any freed pages older than this will be
* reclaimed by the writer. The writer doesn't use any locks when scanning
* this table. This means that there's no guarantee that the writer will
* see the most up-to-date reader info, but that's not required for correct
* operation - all we need is to know the upper bound on the oldest reader,
* we don't care at all about the newest reader. So the only consequence of
* reading stale information here is that old pages might hang around a
* while longer before being reclaimed. That's actually good anyway, because
* the longer we delay reclaiming old pages, the more likely it is that a
* string of contiguous pages can be found after coalescing old pages from
* many old transactions together.
*
* @todo We don't actually do such coalescing yet, we grab pages from one
* old transaction at a time.
* @{
*/
/** Number of slots in the reader table.
* This value was chosen somewhat arbitrarily. 126 readers plus a
* couple mutexes fit exactly into 8KB on my development machine.
* Applications should set the table size using #mdb_env_set_maxreaders().
*/
#define DEFAULT_READERS 126
/** The size of a CPU cache line in bytes. We want our lock structures
* aligned to this size to avoid false cache line sharing in the
* lock table.
* This value works for most CPUs. For Itanium this should be 128.
*/
#ifndef CACHELINE
#define CACHELINE 64
#endif
/** The information we store in a single slot of the reader table.
* In addition to a transaction ID, we also record the process and
* thread ID that owns a slot, so that we can detect stale information,
* e.g. threads or processes that went away without cleaning up.
* @note We currently don't check for stale records. We simply re-init
* the table when we know that we're the only process opening the
* lock file.
*/
typedef struct MDB_rxbody {
/** Current Transaction ID when this transaction began, or (txnid_t)-1.
* Multiple readers that start at the same time will probably have the
* same ID here. Again, it's not important to exclude them from
* anything; all we need to know is which version of the DB they
* started from so we can avoid overwriting any data used in that
* particular version.
*/
txnid_t mrb_txnid;
/** The process ID of the process owning this reader txn. */
pid_t mrb_pid;
/** The thread ID of the thread owning this txn. */
pthread_t mrb_tid;
} MDB_rxbody;
/** The actual reader record, with cacheline padding. */
typedef struct MDB_reader {
union {
MDB_rxbody mrx;
/** shorthand for mrb_txnid */
#define mr_txnid mru.mrx.mrb_txnid
#define mr_pid mru.mrx.mrb_pid
#define mr_tid mru.mrx.mrb_tid
/** cache line alignment */
char pad[(sizeof(MDB_rxbody)+CACHELINE-1) & ~(CACHELINE-1)];
} mru;
} MDB_reader;
/** The header for the reader table.
* The table resides in a memory-mapped file. (This is a different file
* than is used for the main database.)
*
* For POSIX the actual mutexes reside in the shared memory of this
* mapped file. On Windows, mutexes are named objects allocated by the
* kernel; we store the mutex names in this mapped file so that other
* processes can grab them. This same approach is also used on
* MacOSX/Darwin (using named semaphores) since MacOSX doesn't support
* process-shared POSIX mutexes. For these cases where a named object
* is used, the object name is derived from a 64 bit FNV hash of the
* environment pathname. As such, naming collisions are extremely
* unlikely. If a collision occurs, the results are unpredictable.
*/
typedef struct MDB_txbody {
/** Stamp identifying this as an MDB file. It must be set
* to #MDB_MAGIC. */
uint32_t mtb_magic;
/** Version number of this lock file. Must be set to #MDB_VERSION. */
uint32_t mtb_version;
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
char mtb_rmname[MNAME_LEN];
#else
/** Mutex protecting access to this table.
* This is the reader lock that #LOCK_MUTEX_R acquires.
*/
pthread_mutex_t mtb_mutex;
#endif
/** The ID of the last transaction committed to the database.
* This is recorded here only for convenience; the value can always
* be determined by reading the main database meta pages.
*/
txnid_t mtb_txnid;
/** The number of slots that have been used in the reader table.
* This always records the maximum count, it is not decremented
* when readers release their slots.
*/
unsigned mtb_numreaders;
} MDB_txbody;
/** The actual reader table definition. */
typedef struct MDB_txninfo {
union {
MDB_txbody mtb;
#define mti_magic mt1.mtb.mtb_magic
#define mti_version mt1.mtb.mtb_version
#define mti_mutex mt1.mtb.mtb_mutex
#define mti_rmname mt1.mtb.mtb_rmname
#define mti_txnid mt1.mtb.mtb_txnid
#define mti_numreaders mt1.mtb.mtb_numreaders
char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
} mt1;
union {
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
char mt2_wmname[MNAME_LEN];
#define mti_wmname mt2.mt2_wmname
#else
pthread_mutex_t mt2_wmutex;
#define mti_wmutex mt2.mt2_wmutex
#endif
char pad[(MNAME_LEN+CACHELINE-1) & ~(CACHELINE-1)];
} mt2;
MDB_reader mti_readers[1];
} MDB_txninfo;
/** @} */
/** Common header for all page types.
* Overflow records occupy a number of contiguous pages with no
* headers on any page after the first.
*/
typedef struct MDB_page {
#define mp_pgno mp_p.p_pgno
#define mp_next mp_p.p_next
union {
pgno_t p_pgno; /**< page number */
void * p_next; /**< for in-memory list of freed structs */
} mp_p;
uint16_t mp_pad;
/** @defgroup mdb_page Page Flags
* @ingroup internal
* Flags for the page headers.
* @{
*/
#define P_BRANCH 0x01 /**< branch page */
#define P_LEAF 0x02 /**< leaf page */
#define P_OVERFLOW 0x04 /**< overflow page */
#define P_META 0x08 /**< meta page */
#define P_DIRTY 0x10 /**< dirty page */
#define P_LEAF2 0x20 /**< for #MDB_DUPFIXED records */
#define P_SUBP 0x40 /**< for #MDB_DUPSORT sub-pages */
/** @} */
uint16_t mp_flags; /**< @ref mdb_page */
#define mp_lower mp_pb.pb.pb_lower
#define mp_upper mp_pb.pb.pb_upper
#define mp_pages mp_pb.pb_pages
union {
struct {
indx_t pb_lower; /**< lower bound of free space */
indx_t pb_upper; /**< upper bound of free space */
} pb;
uint32_t pb_pages; /**< number of overflow pages */
} mp_pb;
indx_t mp_ptrs[1]; /**< dynamic size */
} MDB_page;
/** Size of the page header, excluding dynamic data at the end */
#define PAGEHDRSZ ((unsigned) offsetof(MDB_page, mp_ptrs))
/** Address of first usable data byte in a page, after the header */
#define METADATA(p) ((void *)((char *)(p) + PAGEHDRSZ))
/** Number of nodes on a page */
#define NUMKEYS(p) (((p)->mp_lower - PAGEHDRSZ) >> 1)
/** The amount of space remaining in the page */
#define SIZELEFT(p) (indx_t)((p)->mp_upper - (p)->mp_lower)
/** The percentage of space used in the page, in tenths of a percent. */
#define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \
((env)->me_psize - PAGEHDRSZ))
/** The minimum page fill factor, in tenths of a percent.
* Pages emptier than this are candidates for merging.
*/
#define FILL_THRESHOLD 250
/** Test if a page is a leaf page */
#define IS_LEAF(p) F_ISSET((p)->mp_flags, P_LEAF)
/** Test if a page is a LEAF2 page */
#define IS_LEAF2(p) F_ISSET((p)->mp_flags, P_LEAF2)
/** Test if a page is a branch page */
#define IS_BRANCH(p) F_ISSET((p)->mp_flags, P_BRANCH)
/** Test if a page is an overflow page */
#define IS_OVERFLOW(p) F_ISSET((p)->mp_flags, P_OVERFLOW)
/** Test if a page is a sub page */
#define IS_SUBP(p) F_ISSET((p)->mp_flags, P_SUBP)
/** The number of overflow pages needed to store the given size. */
#define OVPAGES(size, psize) ((PAGEHDRSZ-1 + (size)) / (psize) + 1)
/** Header for a single key/data pair within a page.
* We guarantee 2-byte alignment for nodes.
*/
typedef struct MDB_node {
/** lo and hi are used for data size on leaf nodes and for
* child pgno on branch nodes. On 64 bit platforms, flags
* is also used for pgno. (Branch nodes have no flags).
* They are in host byte order in case that lets some
* accesses be optimized into a 32-bit word access.
*/
#define mn_lo mn_offset[BYTE_ORDER!=LITTLE_ENDIAN]
#define mn_hi mn_offset[BYTE_ORDER==LITTLE_ENDIAN] /**< part of dsize or pgno */
unsigned short mn_offset[2]; /**< storage for #mn_lo and #mn_hi */
/** @defgroup mdb_node Node Flags
* @ingroup internal
* Flags for node headers.
* @{
*/
#define F_BIGDATA 0x01 /**< data put on overflow page */
#define F_SUBDATA 0x02 /**< data is a sub-database */
#define F_DUPDATA 0x04 /**< data has duplicates */
/** valid flags for #mdb_node_add() */
#define NODE_ADD_FLAGS (F_DUPDATA|F_SUBDATA|MDB_RESERVE|MDB_APPEND)
/** @} */
unsigned short mn_flags; /**< @ref mdb_node */
unsigned short mn_ksize; /**< key size */
char mn_data[1]; /**< key and data are appended here */
} MDB_node;
/** Size of the node header, excluding dynamic data at the end */
#define NODESIZE offsetof(MDB_node, mn_data)
/** Bit position of top word in page number, for shifting mn_flags */
#define PGNO_TOPWORD ((pgno_t)-1 > 0xffffffffu ? 32 : 0)
/** Size of a node in a branch page with a given key.
* This is just the node header plus the key, there is no data.
*/
#define INDXSIZE(k) (NODESIZE + ((k) == NULL ? 0 : (k)->mv_size))
/** Size of a node in a leaf page with a given key and data.
* This is node header plus key plus data size.
*/
#define LEAFSIZE(k, d) (NODESIZE + (k)->mv_size + (d)->mv_size)
/** Address of node \b i in page \b p */
#define NODEPTR(p, i) ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i]))
/** Address of the key for the node */
#define NODEKEY(node) (void *)((node)->mn_data)
/** Address of the data for a node */
#define NODEDATA(node) (void *)((char *)(node)->mn_data + (node)->mn_ksize)
/** Get the page number pointed to by a branch node */
#define NODEPGNO(node) \
((node)->mn_lo | ((pgno_t) (node)->mn_hi << 16) | \
(PGNO_TOPWORD ? ((pgno_t) (node)->mn_flags << PGNO_TOPWORD) : 0))
/** Set the page number in a branch node */
#define SETPGNO(node,pgno) do { \
(node)->mn_lo = (pgno) & 0xffff; (node)->mn_hi = (pgno) >> 16; \
if (PGNO_TOPWORD) (node)->mn_flags = (pgno) >> PGNO_TOPWORD; } while(0)
/** Get the size of the data in a leaf node */
#define NODEDSZ(node) ((node)->mn_lo | ((unsigned)(node)->mn_hi << 16))
/** Set the size of the data for a leaf node */
#define SETDSZ(node,size) do { \
(node)->mn_lo = (size) & 0xffff; (node)->mn_hi = (size) >> 16;} while(0)
/** The size of a key in a node */
#define NODEKSZ(node) ((node)->mn_ksize)
/** Copy a page number from src to dst */
#ifdef MISALIGNED_OK
#define COPY_PGNO(dst,src) dst = src
#else
#if SIZE_MAX > 4294967295UL
#define COPY_PGNO(dst,src) do { \
unsigned short *s, *d; \
s = (unsigned short *)&(src); \
d = (unsigned short *)&(dst); \
*d++ = *s++; \
*d++ = *s++; \
*d++ = *s++; \
*d = *s; \
} while (0)
#else
#define COPY_PGNO(dst,src) do { \
unsigned short *s, *d; \
s = (unsigned short *)&(src); \
d = (unsigned short *)&(dst); \
*d++ = *s++; \
*d = *s; \
} while (0)
#endif
#endif
/** The address of a key in a LEAF2 page.
* LEAF2 pages are used for #MDB_DUPFIXED sorted-duplicate sub-DBs.
* There are no node headers, keys are stored contiguously.
*/
#define LEAF2KEY(p, i, ks) ((char *)(p) + PAGEHDRSZ + ((i)*(ks)))
/** Set the \b node's key into \b key, if requested. */
#define MDB_GET_KEY(node, key) { if ((key) != NULL) { \
(key)->mv_size = NODEKSZ(node); (key)->mv_data = NODEKEY(node); } }
/** Information about a single database in the environment. */
typedef struct MDB_db {
uint32_t md_pad; /**< also ksize for LEAF2 pages */
uint16_t md_flags; /**< @ref mdb_open */
uint16_t md_depth; /**< depth of this tree */
pgno_t md_branch_pages; /**< number of internal pages */
pgno_t md_leaf_pages; /**< number of leaf pages */
pgno_t md_overflow_pages; /**< number of overflow pages */
size_t md_entries; /**< number of data items */
pgno_t md_root; /**< the root page of this tree */
} MDB_db;
/** Handle for the DB used to track free pages. */
#define FREE_DBI 0
/** Handle for the default DB. */
#define MAIN_DBI 1
/** Meta page content. */
typedef struct MDB_meta {
/** Stamp identifying this as an MDB file. It must be set
* to #MDB_MAGIC. */
uint32_t mm_magic;
/** Version number of this lock file. Must be set to #MDB_VERSION. */
uint32_t mm_version;
void *mm_address; /**< address for fixed mapping */
size_t mm_mapsize; /**< size of mmap region */
MDB_db mm_dbs[2]; /**< first is free space, 2nd is main db */
/** The size of pages used in this DB */
#define mm_psize mm_dbs[0].md_pad
/** Any persistent environment flags. @ref mdb_env */
#define mm_flags mm_dbs[0].md_flags
pgno_t mm_last_pg; /**< last used page in file */
txnid_t mm_txnid; /**< txnid that committed this page */
} MDB_meta;
/** Buffer for a stack-allocated dirty page.
* The members define size and alignment, and silence type
* aliasing warnings. They are not used directly; that could
* mean incorrectly using several union members in parallel.
*/
typedef union MDB_pagebuf {
char mb_raw[MDB_PAGESIZE];
MDB_page mb_page;
struct {
char mm_pad[PAGEHDRSZ];
MDB_meta mm_meta;
} mb_metabuf;
} MDB_pagebuf;
/** Auxiliary DB info.
* The information here is mostly static/read-only. There is
* only a single copy of this record in the environment.
*/
typedef struct MDB_dbx {
MDB_val md_name; /**< name of the database */
MDB_cmp_func *md_cmp; /**< function for comparing keys */
MDB_cmp_func *md_dcmp; /**< function for comparing data items */
MDB_rel_func *md_rel; /**< user relocate function */
void *md_relctx; /**< user-provided context for md_rel */
} MDB_dbx;
/** A database transaction.
* Every operation requires a transaction handle.
*/
struct MDB_txn {
MDB_txn *mt_parent; /**< parent of a nested txn */
MDB_txn *mt_child; /**< nested txn under this txn */
pgno_t mt_next_pgno; /**< next unallocated page */
/** The ID of this transaction. IDs are integers incrementing from 1.
* Only committed write transactions increment the ID. If a transaction
* aborts, the ID may be re-used by the next writer.
*/
txnid_t mt_txnid;
MDB_env *mt_env; /**< the DB environment */
/** The list of pages that became unused during this transaction.
*/
MDB_IDL mt_free_pgs;
union {
MDB_ID2L dirty_list; /**< modified pages */
MDB_reader *reader; /**< this thread's slot in the reader table */
} mt_u;
/** Array of records for each DB known in the environment. */
MDB_dbx *mt_dbxs;
/** Array of MDB_db records for each known DB */
MDB_db *mt_dbs;
/** @defgroup mt_dbflag Transaction DB Flags
* @ingroup internal
* @{
*/
#define DB_DIRTY 0x01 /**< DB was written in this txn */
#define DB_STALE 0x02 /**< DB record is older than txnID */
/** @} */
/** Array of cursors for each DB */
MDB_cursor **mt_cursors;
/** Array of flags for each DB */
unsigned char *mt_dbflags;
/** Number of DB records in use. This number only ever increments;
* we don't decrement it when individual DB handles are closed.
*/
MDB_dbi mt_numdbs;
/** @defgroup mdb_txn Transaction Flags
* @ingroup internal
* @{
*/
#define MDB_TXN_RDONLY 0x01 /**< read-only transaction */
#define MDB_TXN_ERROR 0x02 /**< an error has occurred */
/** @} */
unsigned int mt_flags; /**< @ref mdb_txn */
/** Tracks which of the two meta pages was used at the start
* of this transaction.
*/
unsigned int mt_toggle;
};
/** Enough space for 2^32 nodes with minimum of 2 keys per node. I.e., plenty.
* At 4 keys per node, enough for 2^64 nodes, so there's probably no need to
* raise this on a 64 bit machine.
*/
#define CURSOR_STACK 32
struct MDB_xcursor;
/** Cursors are used for all DB operations */
struct MDB_cursor {
/** Next cursor on this DB in this txn */
MDB_cursor *mc_next;
/** Original cursor if this is a shadow */
MDB_cursor *mc_orig;
/** Context used for databases with #MDB_DUPSORT, otherwise NULL */
struct MDB_xcursor *mc_xcursor;
/** The transaction that owns this cursor */
MDB_txn *mc_txn;
/** The database handle this cursor operates on */
MDB_dbi mc_dbi;
/** The database record for this cursor */
MDB_db *mc_db;
/** The database auxiliary record for this cursor */
MDB_dbx *mc_dbx;
/** The @ref mt_dbflag for this database */
unsigned char *mc_dbflag;
unsigned short mc_snum; /**< number of pushed pages */
unsigned short mc_top; /**< index of top page, normally mc_snum-1 */
/** @defgroup mdb_cursor Cursor Flags
* @ingroup internal
* Cursor state flags.
* @{
*/
#define C_INITIALIZED 0x01 /**< cursor has been initialized and is valid */
#define C_EOF 0x02 /**< No more data */
#define C_SUB 0x04 /**< Cursor is a sub-cursor */
#define C_SHADOW 0x08 /**< Cursor is a dup from a parent txn */
#define C_ALLOCD 0x10 /**< Cursor was malloc'd */
#define C_SPLITTING 0x20 /**< Cursor is in page_split */
/** @} */
unsigned int mc_flags; /**< @ref mdb_cursor */
MDB_page *mc_pg[CURSOR_STACK]; /**< stack of pushed pages */
indx_t mc_ki[CURSOR_STACK]; /**< stack of page indices */
};
/** Context for sorted-dup records.
* We could have gone to a fully recursive design, with arbitrarily
* deep nesting of sub-databases. But for now we only handle these
* levels - main DB, optional sub-DB, sorted-duplicate DB.
*/
typedef struct MDB_xcursor {
/** A sub-cursor for traversing the Dup DB */
MDB_cursor mx_cursor;
/** The database record for this Dup DB */
MDB_db mx_db;
/** The auxiliary DB record for this Dup DB */
MDB_dbx mx_dbx;
/** The @ref mt_dbflag for this Dup DB */
unsigned char mx_dbflag;
} MDB_xcursor;
/** A set of pages freed by an earlier transaction. */
typedef struct MDB_oldpages {
/** Usually we only read one record from the FREEDB at a time, but
* in case we read more, this will chain them together.
*/
struct MDB_oldpages *mo_next;
/** The ID of the transaction in which these pages were freed. */
txnid_t mo_txnid;
/** An #MDB_IDL of the pages */
pgno_t mo_pages[1]; /* dynamic */
} MDB_oldpages;
/** The database environment. */
struct MDB_env {
HANDLE me_fd; /**< The main data file */
HANDLE me_lfd; /**< The lock file */
HANDLE me_mfd; /**< just for writing the meta pages */
/** Failed to update the meta page. Probably an I/O error. */
#define MDB_FATAL_ERROR 0x80000000U
uint32_t me_flags; /**< @ref mdb_env */
unsigned int me_psize; /**< size of a page, from #GET_PAGESIZE */
unsigned int me_maxreaders; /**< size of the reader table */
unsigned int me_numreaders; /**< max numreaders set by this env */
MDB_dbi me_numdbs; /**< number of DBs opened */
MDB_dbi me_maxdbs; /**< size of the DB table */
pid_t me_pid; /**< process ID of this env */
char *me_path; /**< path to the DB files */
char *me_map; /**< the memory map of the data file */
MDB_txninfo *me_txns; /**< the memory map of the lock file */
MDB_meta *me_metas[2]; /**< pointers to the two meta pages */
MDB_txn *me_txn; /**< current write transaction */
size_t me_mapsize; /**< size of the data memory map */
off_t me_size; /**< current file size */
pgno_t me_maxpg; /**< me_mapsize / me_psize */
txnid_t me_pgfirst; /**< ID of first old page record we used */
txnid_t me_pglast; /**< ID of last old page record we used */
MDB_dbx *me_dbxs; /**< array of static DB info */
uint16_t *me_dbflags; /**< array of DB flags */
MDB_oldpages *me_pghead; /**< list of old page records */
MDB_oldpages *me_pgfree; /**< list of page records to free */
pthread_key_t me_txkey; /**< thread-key for readers */
MDB_page *me_dpages; /**< list of malloc'd blocks for re-use */
/** IDL of pages that became unused in a write txn */
MDB_IDL me_free_pgs;
/** ID2L of pages that were written during a write txn */
MDB_ID2 me_dirty_list[MDB_IDL_UM_SIZE];
#ifdef _WIN32
HANDLE me_rmutex; /* Windows mutexes don't reside in shared mem */
HANDLE me_wmutex;
#elif defined(MDB_USE_POSIX_SEM)
sem_t *me_rmutex; /* Shared mutexes are not supported */
sem_t *me_wmutex;
#endif
};
/** max number of pages to commit in one writev() call */
#define MDB_COMMIT_PAGES 64
#if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES
#undef MDB_COMMIT_PAGES
#define MDB_COMMIT_PAGES IOV_MAX
#endif
static int mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp);
static int mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp);
static int mdb_page_touch(MDB_cursor *mc);
static int mdb_page_get(MDB_txn *txn, pgno_t pgno, MDB_page **mp);
static int mdb_page_search_root(MDB_cursor *mc,
MDB_val *key, int modify);
#define MDB_PS_MODIFY 1
#define MDB_PS_ROOTONLY 2
static int mdb_page_search(MDB_cursor *mc,
MDB_val *key, int flags);
static int mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst);
#define MDB_SPLIT_REPLACE MDB_APPENDDUP /**< newkey is not new */
static int mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
pgno_t newpgno, unsigned int nflags);
static int mdb_env_read_header(MDB_env *env, MDB_meta *meta);
static int mdb_env_pick_meta(const MDB_env *env);
static int mdb_env_write_meta(MDB_txn *txn);
static void mdb_env_close0(MDB_env *env, int excl);
static MDB_node *mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp);
static int mdb_node_add(MDB_cursor *mc, indx_t indx,
MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags);
static void mdb_node_del(MDB_page *mp, indx_t indx, int ksize);
static void mdb_node_shrink(MDB_page *mp, indx_t indx);
static int mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst);
static int mdb_node_read(MDB_txn *txn, MDB_node *leaf, MDB_val *data);
static size_t mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data);
static size_t mdb_branch_size(MDB_env *env, MDB_val *key);
static int mdb_rebalance(MDB_cursor *mc);
static int mdb_update_key(MDB_page *mp, indx_t indx, MDB_val *key);
static void mdb_cursor_pop(MDB_cursor *mc);
static int mdb_cursor_push(MDB_cursor *mc, MDB_page *mp);
static int mdb_cursor_del0(MDB_cursor *mc, MDB_node *leaf);
static int mdb_cursor_sibling(MDB_cursor *mc, int move_right);
static int mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
static int mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
static int mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op,
int *exactp);
static int mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data);
static int mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data);
static void mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);
static void mdb_xcursor_init0(MDB_cursor *mc);
static void mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node);
static int mdb_drop0(MDB_cursor *mc, int subs);
static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
/** @cond */
static MDB_cmp_func mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int, mdb_cmp_cint, mdb_cmp_long;
/** @endcond */
#ifdef _WIN32
static SECURITY_DESCRIPTOR mdb_null_sd;
static SECURITY_ATTRIBUTES mdb_all_sa;
static int mdb_sec_inited;
#endif
/** Return the library version info. */
char *
mdb_version(int *major, int *minor, int *patch)
{
if (major) *major = MDB_VERSION_MAJOR;
if (minor) *minor = MDB_VERSION_MINOR;
if (patch) *patch = MDB_VERSION_PATCH;
return MDB_VERSION_STRING;
}
/** Table of descriptions for MDB @ref errors */
static char *const mdb_errstr[] = {
"MDB_KEYEXIST: Key/data pair already exists",
"MDB_NOTFOUND: No matching key/data pair found",
"MDB_PAGE_NOTFOUND: Requested page not found",
"MDB_CORRUPTED: Located page was wrong type",
"MDB_PANIC: Update of meta page failed",
"MDB_VERSION_MISMATCH: Database environment version mismatch",
"MDB_INVALID: File is not an MDB file",
"MDB_MAP_FULL: Environment mapsize limit reached",
"MDB_DBS_FULL: Environment maxdbs limit reached",
"MDB_READERS_FULL: Environment maxreaders limit reached",
"MDB_TLS_FULL: Thread-local storage keys full - too many environments open",
"MDB_TXN_FULL: Nested transaction has too many dirty pages - transaction too big",
"MDB_CURSOR_FULL: Internal error - cursor stack limit reached",
"MDB_PAGE_FULL: Internal error - page has no more space"
};
char *
mdb_strerror(int err)
{
int i;
if (!err)
return ("Successful return: 0");
if (err >= MDB_KEYEXIST && err <= MDB_LAST_ERRCODE) {
i = err - MDB_KEYEXIST;
return mdb_errstr[i];
}
return strerror(err);
}
#if MDB_DEBUG
/** Display a key in hexadecimal and return the address of the result.
* @param[in] key the key to display
* @param[in] buf the buffer to write into. Should always be #DKBUF.
* @return The key in hexadecimal form.
*/
char *
mdb_dkey(MDB_val *key, char *buf)
{
char *ptr = buf;
unsigned char *c = key->mv_data;
unsigned int i;
if (key->mv_size > MAXKEYSIZE)
return "MAXKEYSIZE";
/* may want to make this a dynamic check: if the key is mostly
* printable characters, print it as-is instead of converting to hex.
*/
#if 1
buf[0] = '\0';
for (i=0; i<key->mv_size; i++)
ptr += sprintf(ptr, "%02x", *c++);
#else
sprintf(buf, "%.*s", key->mv_size, key->mv_data);
#endif
return buf;
}
/** Display all the keys in the page. */
static void
mdb_page_list(MDB_page *mp)
{
MDB_node *node;
unsigned int i, nkeys, nsize;
MDB_val key;
DKBUF;
nkeys = NUMKEYS(mp);
fprintf(stderr, "numkeys %d\n", nkeys);
for (i=0; i<nkeys; i++) {
node = NODEPTR(mp, i);
key.mv_size = node->mn_ksize;
key.mv_data = node->mn_data;
nsize = NODESIZE + NODEKSZ(node) + sizeof(indx_t);
if (F_ISSET(node->mn_flags, F_BIGDATA))
nsize += sizeof(pgno_t);
else
nsize += NODEDSZ(node);
fprintf(stderr, "key %d: nsize %d, %s\n", i, nsize, DKEY(&key));
}
}
void
mdb_cursor_chk(MDB_cursor *mc)
{
unsigned int i;
MDB_node *node;
MDB_page *mp;
if (!mc->mc_snum && !(mc->mc_flags & C_INITIALIZED)) return;
for (i=0; i<mc->mc_top; i++) {
mp = mc->mc_pg[i];
node = NODEPTR(mp, mc->mc_ki[i]);
if (NODEPGNO(node) != mc->mc_pg[i+1]->mp_pgno)
printf("oops!\n");
}
if (mc->mc_ki[i] >= NUMKEYS(mc->mc_pg[i]))
printf("ack!\n");
}
#endif
#if MDB_DEBUG > 2
/** Count all the pages in each DB and in the freelist
* and make sure it matches the actual number of pages
* being used.
*/
static void mdb_audit(MDB_txn *txn)
{
MDB_cursor mc;
MDB_val key, data;
MDB_ID freecount, count;
MDB_dbi i;
int rc;
freecount = 0;
mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
freecount += *(MDB_ID *)data.mv_data;
count = 0;
for (i = 0; i<txn->mt_numdbs; i++) {
MDB_xcursor mx, *mxp;
mxp = (txn->mt_dbs[i].md_flags & MDB_DUPSORT) ? &mx : NULL;
mdb_cursor_init(&mc, txn, i, mxp);
if (txn->mt_dbs[i].md_root == P_INVALID)
continue;
count += txn->mt_dbs[i].md_branch_pages +
txn->mt_dbs[i].md_leaf_pages +
txn->mt_dbs[i].md_overflow_pages;
if (txn->mt_dbs[i].md_flags & MDB_DUPSORT) {
mdb_page_search(&mc, NULL, 0);
do {
unsigned j;
MDB_page *mp;
mp = mc.mc_pg[mc.mc_top];
for (j=0; j<NUMKEYS(mp); j++) {
MDB_node *leaf = NODEPTR(mp, j);
if (leaf->mn_flags & F_SUBDATA) {
MDB_db db;
memcpy(&db, NODEDATA(leaf), sizeof(db));
count += db.md_branch_pages + db.md_leaf_pages +
db.md_overflow_pages;
}
}
}
while (mdb_cursor_sibling(&mc, 1) == 0);
}
}
if (freecount + count + 2 /* metapages */ != txn->mt_next_pgno) {
fprintf(stderr, "audit: %lu freecount: %lu count: %lu total: %lu next_pgno: %lu\n",
txn->mt_txnid, freecount, count+2, freecount+count+2, txn->mt_next_pgno);
}
}
#endif
int
mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
{
return txn->mt_dbxs[dbi].md_cmp(a, b);
}
int
mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
{
if (txn->mt_dbxs[dbi].md_dcmp)
return txn->mt_dbxs[dbi].md_dcmp(a, b);
else
return EINVAL; /* too bad you can't distinguish this from a valid result */
}
/** Allocate a single page.
* Re-use old malloc'd pages first, otherwise just malloc.
*/
static MDB_page *
mdb_page_malloc(MDB_cursor *mc) {
MDB_page *ret;
size_t sz = mc->mc_txn->mt_env->me_psize;
if ((ret = mc->mc_txn->mt_env->me_dpages) != NULL) {
VGMEMP_ALLOC(mc->mc_txn->mt_env, ret, sz);
VGMEMP_DEFINED(ret, sizeof(ret->mp_next));
mc->mc_txn->mt_env->me_dpages = ret->mp_next;
} else if ((ret = malloc(sz)) != NULL) {
VGMEMP_ALLOC(mc->mc_txn->mt_env, ret, sz);
}
return ret;
}
/** Allocate pages for writing.
* If there are free pages available from older transactions, they
* will be re-used first. Otherwise a new page will be allocated.
* @param[in] mc cursor A cursor handle identifying the transaction and
* database for which we are allocating.
* @param[in] num the number of pages to allocate.
* @param[out] mp Address of the allocated page(s). Requests for multiple pages
* will always be satisfied by a single contiguous chunk of memory.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
{
MDB_txn *txn = mc->mc_txn;
MDB_page *np;
pgno_t pgno = P_INVALID;
MDB_ID2 mid;
int rc;
*mp = NULL;
/* The free list won't have any content at all until txn 2 has
* committed. The pages freed by txn 2 will be unreferenced
* after txn 3 commits, and so will be safe to re-use in txn 4.
*/
if (txn->mt_txnid > 3) {
if (!txn->mt_env->me_pghead &&
txn->mt_dbs[FREE_DBI].md_root != P_INVALID) {
/* See if there's anything in the free DB */
int j;
MDB_reader *r;
MDB_cursor m2;
MDB_node *leaf;
MDB_val data;
txnid_t *kptr, last;
mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
if (!txn->mt_env->me_pgfirst) {
mdb_page_search(&m2, NULL, 0);
leaf = NODEPTR(m2.mc_pg[m2.mc_top], 0);
kptr = (txnid_t *)NODEKEY(leaf);
last = *kptr;
} else {
MDB_val key;
int exact;
again:
exact = 0;
last = txn->mt_env->me_pglast + 1;
leaf = NULL;
key.mv_data = &last;
key.mv_size = sizeof(last);
rc = mdb_cursor_set(&m2, &key, &data, MDB_SET, &exact);
if (rc)
goto none;
last = *(txnid_t *)key.mv_data;
}
/* Unusable if referred by a meta page or reader... */
j = 1;
if (last < txn->mt_txnid-1) {
j = txn->mt_env->me_txns->mti_numreaders;
r = txn->mt_env->me_txns->mti_readers + j;
for (j = -j; j && (last<r[j].mr_txnid || !r[j].mr_pid); j++) ;
}
if (!j) {
/* It's usable, grab it.
*/
MDB_oldpages *mop;
pgno_t *idl;
if (!txn->mt_env->me_pgfirst) {
mdb_node_read(txn, leaf, &data);
}
txn->mt_env->me_pglast = last;
if (!txn->mt_env->me_pgfirst)
txn->mt_env->me_pgfirst = last;
idl = (MDB_ID *) data.mv_data;
/* We might have a zero-length IDL due to freelist growth
* during a prior commit
*/
if (!idl[0]) goto again;
mop = malloc(sizeof(MDB_oldpages) + MDB_IDL_SIZEOF(idl) - sizeof(pgno_t));
if (!mop)
return ENOMEM;
mop->mo_next = txn->mt_env->me_pghead;
mop->mo_txnid = last;
txn->mt_env->me_pghead = mop;
memcpy(mop->mo_pages, idl, MDB_IDL_SIZEOF(idl));
#if MDB_DEBUG > 1
{
unsigned int i;
DPRINTF("IDL read txn %zu root %zu num %zu",
mop->mo_txnid, txn->mt_dbs[FREE_DBI].md_root, idl[0]);
for (i=0; i<idl[0]; i++) {
DPRINTF("IDL %zu", idl[i+1]);
}
}
#endif
}
}
none:
if (txn->mt_env->me_pghead) {
MDB_oldpages *mop = txn->mt_env->me_pghead;
if (num > 1) {
/* FIXME: For now, always use fresh pages. We
* really ought to search the free list for a
* contiguous range.
*/
;
} else {
/* peel pages off tail, so we only have to truncate the list */
pgno = MDB_IDL_LAST(mop->mo_pages);
if (MDB_IDL_IS_RANGE(mop->mo_pages)) {
mop->mo_pages[2]++;
if (mop->mo_pages[2] > mop->mo_pages[1])
mop->mo_pages[0] = 0;
} else {
mop->mo_pages[0]--;
}
if (MDB_IDL_IS_ZERO(mop->mo_pages)) {
txn->mt_env->me_pghead = mop->mo_next;
if (mc->mc_dbi == FREE_DBI) {
mop->mo_next = txn->mt_env->me_pgfree;
txn->mt_env->me_pgfree = mop;
} else {
free(mop);
}
}
}
}
}
if (pgno == P_INVALID) {
/* DB size is maxed out */
if (txn->mt_next_pgno + num >= txn->mt_env->me_maxpg) {
DPUTS("DB size maxed out");
return MDB_MAP_FULL;
}
}
if (txn->mt_env->me_flags & MDB_WRITEMAP) {
if (pgno == P_INVALID) {
pgno = txn->mt_next_pgno;
txn->mt_next_pgno += num;
}
np = (MDB_page *)(txn->mt_env->me_map + txn->mt_env->me_psize * pgno);
np->mp_pgno = pgno;
} else {
if (txn->mt_env->me_dpages && num == 1) {
np = txn->mt_env->me_dpages;
VGMEMP_ALLOC(txn->mt_env, np, txn->mt_env->me_psize);
VGMEMP_DEFINED(np, sizeof(np->mp_next));
txn->mt_env->me_dpages = np->mp_next;
} else {
size_t sz = txn->mt_env->me_psize * num;
if ((np = malloc(sz)) == NULL)
return ENOMEM;
VGMEMP_ALLOC(txn->mt_env, np, sz);
}
if (pgno == P_INVALID) {
np->mp_pgno = txn->mt_next_pgno;
txn->mt_next_pgno += num;
} else {
np->mp_pgno = pgno;
}
}
mid.mid = np->mp_pgno;
mid.mptr = np;
if (txn->mt_env->me_flags & MDB_WRITEMAP) {
mdb_mid2l_append(txn->mt_u.dirty_list, &mid);
} else {
mdb_mid2l_insert(txn->mt_u.dirty_list, &mid);
}
*mp = np;
return MDB_SUCCESS;
}
/** Copy a page: avoid copying unused portions of the page.
* @param[in] dst page to copy into
* @param[in] src page to copy from
*/
static void
mdb_page_copy(MDB_page *dst, MDB_page *src, unsigned int psize)
{
dst->mp_flags = src->mp_flags | P_DIRTY;
dst->mp_pages = src->mp_pages;
if (IS_LEAF2(src)) {
memcpy(dst->mp_ptrs, src->mp_ptrs, psize - PAGEHDRSZ - SIZELEFT(src));
} else {
unsigned int i, nkeys = NUMKEYS(src);
for (i=0; i<nkeys; i++)
dst->mp_ptrs[i] = src->mp_ptrs[i];
memcpy((char *)dst+src->mp_upper, (char *)src+src->mp_upper,
psize - src->mp_upper);
}
}
/** Touch a page: make it dirty and re-insert into tree with updated pgno.
* @param[in] mc cursor pointing to the page to be touched
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_touch(MDB_cursor *mc)
{
MDB_page *mp = mc->mc_pg[mc->mc_top];
pgno_t pgno;
int rc;
if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
MDB_page *np;
if ((rc = mdb_page_alloc(mc, 1, &np)))
return rc;
DPRINTF("touched db %u page %zu -> %zu", mc->mc_dbi, mp->mp_pgno, np->mp_pgno);
assert(mp->mp_pgno != np->mp_pgno);
mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
if (SIZELEFT(mp)) {
/* If page isn't full, just copy the used portion */
mdb_page_copy(np, mp, mc->mc_txn->mt_env->me_psize);
} else {
pgno = np->mp_pgno;
memcpy(np, mp, mc->mc_txn->mt_env->me_psize);
np->mp_pgno = pgno;
np->mp_flags |= P_DIRTY;
}
mp = np;
finish:
/* Adjust other cursors pointing to mp */
if (mc->mc_flags & C_SUB) {
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi-1;
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (m2 == mc) continue;
m3 = &m2->mc_xcursor->mx_cursor;
if (m3->mc_snum < mc->mc_snum) continue;
if (m3->mc_pg[mc->mc_top] == mc->mc_pg[mc->mc_top]) {
m3->mc_pg[mc->mc_top] = mp;
}
}
} else {
MDB_cursor *m2;
for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
if (m2->mc_pg[mc->mc_top] == mc->mc_pg[mc->mc_top]) {
m2->mc_pg[mc->mc_top] = mp;
}
}
}
mc->mc_pg[mc->mc_top] = mp;
/** If this page has a parent, update the parent to point to
* this new page.
*/
if (mc->mc_top)
SETPGNO(NODEPTR(mc->mc_pg[mc->mc_top-1], mc->mc_ki[mc->mc_top-1]), mp->mp_pgno);
else
mc->mc_db->md_root = mp->mp_pgno;
} else if (mc->mc_txn->mt_parent) {
MDB_page *np;
MDB_ID2 mid;
/* If txn has a parent, make sure the page is in our
* dirty list.
*/
if (mc->mc_txn->mt_u.dirty_list[0].mid) {
unsigned x = mdb_mid2l_search(mc->mc_txn->mt_u.dirty_list, mp->mp_pgno);
if (x <= mc->mc_txn->mt_u.dirty_list[0].mid &&
mc->mc_txn->mt_u.dirty_list[x].mid == mp->mp_pgno) {
if (mc->mc_txn->mt_u.dirty_list[x].mptr != mp) {
mp = mc->mc_txn->mt_u.dirty_list[x].mptr;
mc->mc_pg[mc->mc_top] = mp;
}
return 0;
}
}
/* No - copy it */
np = mdb_page_malloc(mc);
if (!np)
return ENOMEM;
memcpy(np, mp, mc->mc_txn->mt_env->me_psize);
mid.mid = np->mp_pgno;
mid.mptr = np;
mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &mid);
mp = np;
goto finish;
}
return 0;
}
int
mdb_env_sync(MDB_env *env, int force)
{
int rc = 0;
if (force || !F_ISSET(env->me_flags, MDB_NOSYNC)) {
if (env->me_flags & MDB_WRITEMAP) {
int flags = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
if (MDB_MSYNC(env->me_map, env->me_mapsize, flags))
rc = ErrCode();
#ifdef _WIN32
else if (flags == MS_SYNC && MDB_FDATASYNC(env->me_fd))
rc = ErrCode();
#endif
} else {
if (MDB_FDATASYNC(env->me_fd))
rc = ErrCode();
}
}
return rc;
}
/** Make shadow copies of all of parent txn's cursors */
static int
mdb_cursor_shadow(MDB_txn *src, MDB_txn *dst)
{
MDB_cursor *mc, *m2;
unsigned int i, j, size;
for (i=0;i<src->mt_numdbs; i++) {
if (src->mt_cursors[i]) {
size = sizeof(MDB_cursor);
if (src->mt_cursors[i]->mc_xcursor)
size += sizeof(MDB_xcursor);
for (m2 = src->mt_cursors[i]; m2; m2=m2->mc_next) {
mc = malloc(size);
if (!mc)
return ENOMEM;
mc->mc_orig = m2;
mc->mc_txn = dst;
mc->mc_dbi = i;
mc->mc_db = &dst->mt_dbs[i];
mc->mc_dbx = m2->mc_dbx;
mc->mc_dbflag = &dst->mt_dbflags[i];
mc->mc_snum = m2->mc_snum;
mc->mc_top = m2->mc_top;
mc->mc_flags = m2->mc_flags | C_SHADOW;
for (j=0; j<mc->mc_snum; j++) {
mc->mc_pg[j] = m2->mc_pg[j];
mc->mc_ki[j] = m2->mc_ki[j];
}
if (m2->mc_xcursor) {
MDB_xcursor *mx, *mx2;
mx = (MDB_xcursor *)(mc+1);
mc->mc_xcursor = mx;
mx2 = m2->mc_xcursor;
mx->mx_db = mx2->mx_db;
mx->mx_dbx = mx2->mx_dbx;
mx->mx_dbflag = mx2->mx_dbflag;
mx->mx_cursor.mc_txn = dst;
mx->mx_cursor.mc_dbi = mx2->mx_cursor.mc_dbi;
mx->mx_cursor.mc_db = &mx->mx_db;
mx->mx_cursor.mc_dbx = &mx->mx_dbx;
mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
mx->mx_cursor.mc_snum = mx2->mx_cursor.mc_snum;
mx->mx_cursor.mc_top = mx2->mx_cursor.mc_top;
mx->mx_cursor.mc_flags = mx2->mx_cursor.mc_flags | C_SHADOW;
for (j=0; j<mx2->mx_cursor.mc_snum; j++) {
mx->mx_cursor.mc_pg[j] = mx2->mx_cursor.mc_pg[j];
mx->mx_cursor.mc_ki[j] = mx2->mx_cursor.mc_ki[j];
}
} else {
mc->mc_xcursor = NULL;
}
mc->mc_next = dst->mt_cursors[i];
dst->mt_cursors[i] = mc;
}
}
}
return MDB_SUCCESS;
}
/** Merge shadow cursors back into parent's */
static void
mdb_cursor_merge(MDB_txn *txn)
{
MDB_dbi i;
for (i=0; i<txn->mt_numdbs; i++) {
if (txn->mt_cursors[i]) {
MDB_cursor *mc;
while ((mc = txn->mt_cursors[i])) {
txn->mt_cursors[i] = mc->mc_next;
if (mc->mc_flags & C_SHADOW) {
MDB_cursor *m2 = mc->mc_orig;
unsigned int j;
m2->mc_snum = mc->mc_snum;
m2->mc_top = mc->mc_top;
for (j=0; j<mc->mc_snum; j++) {
m2->mc_pg[j] = mc->mc_pg[j];
m2->mc_ki[j] = mc->mc_ki[j];
}
}
if (mc->mc_flags & C_ALLOCD)
free(mc);
}
}
}
}
static void
mdb_txn_reset0(MDB_txn *txn);
/** Common code for #mdb_txn_begin() and #mdb_txn_renew().
* @param[in] txn the transaction handle to initialize
* @return 0 on success, non-zero on failure. This can only
* fail for read-only transactions, and then only if the
* reader table is full.
*/
static int
mdb_txn_renew0(MDB_txn *txn)
{
MDB_env *env = txn->mt_env;
unsigned int i;
/* Setup db info */
txn->mt_numdbs = env->me_numdbs;
txn->mt_dbxs = env->me_dbxs; /* mostly static anyway */
if (txn->mt_flags & MDB_TXN_RDONLY) {
MDB_reader *r = pthread_getspecific(env->me_txkey);
if (!r) {
pid_t pid = env->me_pid;
pthread_t tid = pthread_self();
LOCK_MUTEX_R(env);
for (i=0; i<env->me_txns->mti_numreaders; i++)
if (env->me_txns->mti_readers[i].mr_pid == 0)
break;
if (i == env->me_maxreaders) {
UNLOCK_MUTEX_R(env);
return MDB_READERS_FULL;
}
env->me_txns->mti_readers[i].mr_pid = pid;
env->me_txns->mti_readers[i].mr_tid = tid;
if (i >= env->me_txns->mti_numreaders)
env->me_txns->mti_numreaders = i+1;
/* Save numreaders for un-mutexed mdb_env_close() */
env->me_numreaders = env->me_txns->mti_numreaders;
UNLOCK_MUTEX_R(env);
r = &env->me_txns->mti_readers[i];
pthread_setspecific(env->me_txkey, r);
}
txn->mt_txnid = r->mr_txnid = env->me_txns->mti_txnid;
txn->mt_toggle = txn->mt_txnid & 1;
txn->mt_next_pgno = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
txn->mt_u.reader = r;
} else {
LOCK_MUTEX_W(env);
txn->mt_txnid = env->me_txns->mti_txnid;
txn->mt_toggle = txn->mt_txnid & 1;
txn->mt_next_pgno = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
txn->mt_txnid++;
#if MDB_DEBUG
if (txn->mt_txnid == mdb_debug_start)
mdb_debug = 1;
#endif
txn->mt_u.dirty_list = env->me_dirty_list;
txn->mt_u.dirty_list[0].mid = 0;
txn->mt_free_pgs = env->me_free_pgs;
txn->mt_free_pgs[0] = 0;
env->me_txn = txn;
}
/* Copy the DB info and flags */
memcpy(txn->mt_dbs, env->me_metas[txn->mt_toggle]->mm_dbs, 2 * sizeof(MDB_db));
for (i=2; i<txn->mt_numdbs; i++)
txn->mt_dbs[i].md_flags = env->me_dbflags[i];
txn->mt_dbflags[0] = txn->mt_dbflags[1] = 0;
if (txn->mt_numdbs > 2)
memset(txn->mt_dbflags+2, DB_STALE, txn->mt_numdbs-2);
return MDB_SUCCESS;
}
int
mdb_txn_renew(MDB_txn *txn)
{
int rc;
if (! (txn && txn->mt_flags & MDB_TXN_RDONLY))
return EINVAL;
if (txn->mt_env->me_flags & MDB_FATAL_ERROR) {
DPUTS("environment had fatal error, must shutdown!");
return MDB_PANIC;
}
rc = mdb_txn_renew0(txn);
if (rc == MDB_SUCCESS) {
DPRINTF("renew txn %zu%c %p on mdbenv %p, root page %zu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
}
return rc;
}
int
mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
{
MDB_txn *txn;
int rc, size;
if (env->me_flags & MDB_FATAL_ERROR) {
DPUTS("environment had fatal error, must shutdown!");
return MDB_PANIC;
}
if ((env->me_flags & MDB_RDONLY) && !(flags & MDB_RDONLY))
return EACCES;
if (parent) {
/* Nested transactions: Max 1 child, write txns only, no writemap */
if (parent->mt_child ||
(flags & MDB_RDONLY) || (parent->mt_flags & MDB_TXN_RDONLY) ||
(env->me_flags & MDB_WRITEMAP))
{
return EINVAL;
}
}
size = sizeof(MDB_txn) + env->me_maxdbs * (sizeof(MDB_db)+1);
if (!(flags & MDB_RDONLY))
size += env->me_maxdbs * sizeof(MDB_cursor *);
if ((txn = calloc(1, size)) == NULL) {
DPRINTF("calloc: %s", strerror(ErrCode()));
return ENOMEM;
}
txn->mt_dbs = (MDB_db *)(txn+1);
if (flags & MDB_RDONLY) {
txn->mt_flags |= MDB_TXN_RDONLY;
txn->mt_dbflags = (unsigned char *)(txn->mt_dbs + env->me_maxdbs);
} else {
txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
txn->mt_dbflags = (unsigned char *)(txn->mt_cursors + env->me_maxdbs);
}
txn->mt_env = env;
if (parent) {
txn->mt_free_pgs = mdb_midl_alloc();
if (!txn->mt_free_pgs) {
free(txn);
return ENOMEM;
}
txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);
if (!txn->mt_u.dirty_list) {
free(txn->mt_free_pgs);
free(txn);
return ENOMEM;
}
txn->mt_txnid = parent->mt_txnid;
txn->mt_toggle = parent->mt_toggle;
txn->mt_u.dirty_list[0].mid = 0;
txn->mt_free_pgs[0] = 0;
txn->mt_next_pgno = parent->mt_next_pgno;
parent->mt_child = txn;
txn->mt_parent = parent;
txn->mt_numdbs = parent->mt_numdbs;
txn->mt_dbxs = parent->mt_dbxs;
memcpy(txn->mt_dbs, parent->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
memcpy(txn->mt_dbflags, parent->mt_dbflags, txn->mt_numdbs);
mdb_cursor_shadow(parent, txn);
rc = 0;
} else {
rc = mdb_txn_renew0(txn);
}
if (rc)
free(txn);
else {
*ret = txn;
DPRINTF("begin txn %zu%c %p on mdbenv %p, root page %zu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root);
}
return rc;
}
/** Common code for #mdb_txn_reset() and #mdb_txn_abort().
* @param[in] txn the transaction handle to reset
*/
static void
mdb_txn_reset0(MDB_txn *txn)
{
MDB_env *env = txn->mt_env;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
txn->mt_u.reader->mr_txnid = (txnid_t)-1;
} else {
MDB_oldpages *mop;
MDB_page *dp;
unsigned int i;
/* close(free) all cursors */
for (i=0; i<txn->mt_numdbs; i++) {
if (txn->mt_cursors[i]) {
MDB_cursor *mc;
while ((mc = txn->mt_cursors[i])) {
txn->mt_cursors[i] = mc->mc_next;
if (mc->mc_flags & C_ALLOCD)
free(mc);
}
}
}
if (!(env->me_flags & MDB_WRITEMAP)) {
/* return all dirty pages to dpage list */
for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
dp = txn->mt_u.dirty_list[i].mptr;
if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
dp->mp_next = txn->mt_env->me_dpages;
VGMEMP_FREE(txn->mt_env, dp);
txn->mt_env->me_dpages = dp;
} else {
/* large pages just get freed directly */
VGMEMP_FREE(txn->mt_env, dp);
free(dp);
}
}
}
if (txn->mt_parent) {
txn->mt_parent->mt_child = NULL;
mdb_midl_free(txn->mt_free_pgs);
free(txn->mt_u.dirty_list);
return;
} else {
if (mdb_midl_shrink(&txn->mt_free_pgs))
env->me_free_pgs = txn->mt_free_pgs;
}
while ((mop = txn->mt_env->me_pghead)) {
txn->mt_env->me_pghead = mop->mo_next;
free(mop);
}
txn->mt_env->me_pgfirst = 0;
txn->mt_env->me_pglast = 0;
env->me_txn = NULL;
/* The writer mutex was locked in mdb_txn_begin. */
UNLOCK_MUTEX_W(env);
}
}
void
mdb_txn_reset(MDB_txn *txn)
{
if (txn == NULL)
return;
DPRINTF("reset txn %zu%c %p on mdbenv %p, root page %zu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *) txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
mdb_txn_reset0(txn);
}
void
mdb_txn_abort(MDB_txn *txn)
{
if (txn == NULL)
return;
DPRINTF("abort txn %zu%c %p on mdbenv %p, root page %zu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
if (txn->mt_child)
mdb_txn_abort(txn->mt_child);
mdb_txn_reset0(txn);
free(txn);
}
int
mdb_txn_commit(MDB_txn *txn)
{
int n, done;
unsigned int i;
ssize_t rc;
off_t size;
MDB_page *dp;
MDB_env *env;
pgno_t next, freecnt;
MDB_cursor mc;
assert(txn != NULL);
assert(txn->mt_env != NULL);
if (txn->mt_child) {
mdb_txn_commit(txn->mt_child);
txn->mt_child = NULL;
}
env = txn->mt_env;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
if (txn->mt_numdbs > env->me_numdbs) {
/* update the DB flags */
MDB_dbi i;
for (i = env->me_numdbs; i<txn->mt_numdbs; i++)
env->me_dbflags[i] = txn->mt_dbs[i].md_flags;
env->me_numdbs = i;
}
mdb_txn_abort(txn);
return MDB_SUCCESS;
}
if (F_ISSET(txn->mt_flags, MDB_TXN_ERROR)) {
DPUTS("error flag is set, can't commit");
if (txn->mt_parent)
txn->mt_parent->mt_flags |= MDB_TXN_ERROR;
mdb_txn_abort(txn);
return EINVAL;
}
/* Merge (and close) our cursors with parent's */
mdb_cursor_merge(txn);
if (txn->mt_parent) {
MDB_db *ip, *jp;
MDB_dbi i;
unsigned x, y;
MDB_ID2L dst, src;
/* Update parent's DB table */
ip = &txn->mt_parent->mt_dbs[2];
jp = &txn->mt_dbs[2];
for (i = 2; i < txn->mt_numdbs; i++) {
if (ip->md_root != jp->md_root)
*ip = *jp;
ip++; jp++;
}
txn->mt_parent->mt_numdbs = txn->mt_numdbs;
/* Append our free list to parent's */
mdb_midl_append_list(&txn->mt_parent->mt_free_pgs,
txn->mt_free_pgs);
mdb_midl_free(txn->mt_free_pgs);
/* Merge our dirty list with parent's */
dst = txn->mt_parent->mt_u.dirty_list;
src = txn->mt_u.dirty_list;
x = mdb_mid2l_search(dst, src[1].mid);
for (y=1; y<=src[0].mid; y++) {
while (x <= dst[0].mid && dst[x].mid != src[y].mid) x++;
if (x > dst[0].mid)
break;
free(dst[x].mptr);
dst[x].mptr = src[y].mptr;
}
x = dst[0].mid;
for (; y<=src[0].mid; y++) {
if (++x >= MDB_IDL_UM_MAX) {
mdb_txn_abort(txn);
return MDB_TXN_FULL;
}
dst[x] = src[y];
}
dst[0].mid = x;
free(txn->mt_u.dirty_list);
txn->mt_parent->mt_child = NULL;
free(txn);
return MDB_SUCCESS;
}
if (txn != env->me_txn) {
DPUTS("attempt to commit unknown transaction");
mdb_txn_abort(txn);
return EINVAL;
}
if (!txn->mt_u.dirty_list[0].mid)
goto done;
DPRINTF("committing txn %zu %p on mdbenv %p, root page %zu",
txn->mt_txnid, (void *)txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root);
/* Update DB root pointers. Their pages have already been
* touched so this is all in-place and cannot fail.
*/
if (txn->mt_numdbs > 2) {
MDB_dbi i;
MDB_val data;
data.mv_size = sizeof(MDB_db);
mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
for (i = 2; i < txn->mt_numdbs; i++) {
if (txn->mt_dbflags[i] & DB_DIRTY) {
data.mv_data = &txn->mt_dbs[i];
mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data, 0);
}
}
}
mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
/* should only be one record now */
if (env->me_pghead) {
/* make sure first page of freeDB is touched and on freelist */
mdb_page_search(&mc, NULL, MDB_PS_MODIFY);
}
/* Delete IDLs we used from the free list */
if (env->me_pgfirst) {
txnid_t cur;
MDB_val key;
int exact = 0;
key.mv_size = sizeof(cur);
for (cur = env->me_pgfirst; cur <= env->me_pglast; cur++) {
key.mv_data = &cur;
mdb_cursor_set(&mc, &key, NULL, MDB_SET, &exact);
rc = mdb_cursor_del(&mc, 0);
if (rc) {
mdb_txn_abort(txn);
return rc;
}
}
env->me_pgfirst = 0;
env->me_pglast = 0;
}
/* save to free list */
free2:
freecnt = txn->mt_free_pgs[0];
if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
MDB_val key, data;
/* make sure last page of freeDB is touched and on freelist */
key.mv_size = MAXKEYSIZE+1;
key.mv_data = NULL;
mdb_page_search(&mc, &key, MDB_PS_MODIFY);
mdb_midl_sort(txn->mt_free_pgs);
#if MDB_DEBUG > 1
{
unsigned int i;
MDB_IDL idl = txn->mt_free_pgs;
DPRINTF("IDL write txn %zu root %zu num %zu",
txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, idl[0]);
for (i=0; i<idl[0]; i++) {
DPRINTF("IDL %zu", idl[i+1]);
}
}
#endif
/* write to last page of freeDB */
key.mv_size = sizeof(pgno_t);
key.mv_data = &txn->mt_txnid;
data.mv_data = txn->mt_free_pgs;
/* The free list can still grow during this call,
* despite the pre-emptive touches above. So check
* and make sure the entire thing got written.
*/
do {
freecnt = txn->mt_free_pgs[0];
data.mv_size = MDB_IDL_SIZEOF(txn->mt_free_pgs);
rc = mdb_cursor_put(&mc, &key, &data, 0);
if (rc) {
mdb_txn_abort(txn);
return rc;
}
} while (freecnt != txn->mt_free_pgs[0]);
}
/* should only be one record now */
again:
if (env->me_pghead) {
MDB_val key, data;
MDB_oldpages *mop;
pgno_t orig;
txnid_t id;
mop = env->me_pghead;
id = mop->mo_txnid;
key.mv_size = sizeof(id);
key.mv_data = &id;
data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages);
data.mv_data = mop->mo_pages;
orig = mop->mo_pages[0];
/* These steps may grow the freelist again
* due to freed overflow pages...
*/
mdb_cursor_put(&mc, &key, &data, 0);
if (mop == env->me_pghead && env->me_pghead->mo_txnid == id) {
/* could have been used again here */
if (mop->mo_pages[0] != orig) {
data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages);
data.mv_data = mop->mo_pages;
id = mop->mo_txnid;
mdb_cursor_put(&mc, &key, &data, 0);
}
env->me_pghead = NULL;
free(mop);
} else {
/* was completely used up */
mdb_cursor_del(&mc, 0);
if (env->me_pghead)
goto again;
}
env->me_pgfirst = 0;
env->me_pglast = 0;
}
while (env->me_pgfree) {
MDB_oldpages *mop = env->me_pgfree;
env->me_pgfree = mop->mo_next;
free(mop);;
}
/* Check for growth of freelist again */
if (freecnt != txn->mt_free_pgs[0])
goto free2;
if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
if (mdb_midl_shrink(&txn->mt_free_pgs))
env->me_free_pgs = txn->mt_free_pgs;
}
#if MDB_DEBUG > 2
mdb_audit(txn);
#endif
if (env->me_flags & MDB_WRITEMAP) {
for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
dp = txn->mt_u.dirty_list[i].mptr;
/* clear dirty flag */
dp->mp_flags &= ~P_DIRTY;
txn->mt_u.dirty_list[i].mid = 0;
}
txn->mt_u.dirty_list[0].mid = 0;
goto sync;
}
/* Commit up to MDB_COMMIT_PAGES dirty pages to disk until done.
*/
next = 0;
i = 1;
do {
#ifdef _WIN32
/* Windows actually supports scatter/gather I/O, but only on
* unbuffered file handles. Since we're relying on the OS page
* cache for all our data, that's self-defeating. So we just
* write pages one at a time. We use the ov structure to set
* the write offset, to at least save the overhead of a Seek
* system call.
*/
OVERLAPPED ov;
memset(&ov, 0, sizeof(ov));
for (; i<=txn->mt_u.dirty_list[0].mid; i++) {
size_t wsize;
dp = txn->mt_u.dirty_list[i].mptr;
DPRINTF("committing page %zu", dp->mp_pgno);
size = dp->mp_pgno * env->me_psize;
ov.Offset = size & 0xffffffff;
ov.OffsetHigh = size >> 16;
ov.OffsetHigh >>= 16;
/* clear dirty flag */
dp->mp_flags &= ~P_DIRTY;
wsize = env->me_psize;
if (IS_OVERFLOW(dp)) wsize *= dp->mp_pages;
rc = WriteFile(env->me_fd, dp, wsize, NULL, &ov);
if (!rc) {
n = ErrCode();
DPRINTF("WriteFile: %d", n);
mdb_txn_abort(txn);
return n;
}
}
done = 1;
#else
struct iovec iov[MDB_COMMIT_PAGES];
n = 0;
done = 1;
size = 0;
for (; i<=txn->mt_u.dirty_list[0].mid; i++) {
dp = txn->mt_u.dirty_list[i].mptr;
if (dp->mp_pgno != next) {
if (n) {
rc = writev(env->me_fd, iov, n);
if (rc != size) {
n = ErrCode();
if (rc > 0)
DPUTS("short write, filesystem full?");
else
DPRINTF("writev: %s", strerror(n));
mdb_txn_abort(txn);
return n;
}
n = 0;
size = 0;
}
lseek(env->me_fd, dp->mp_pgno * env->me_psize, SEEK_SET);
next = dp->mp_pgno;
}
DPRINTF("committing page %zu", dp->mp_pgno);
iov[n].iov_len = env->me_psize;
if (IS_OVERFLOW(dp)) iov[n].iov_len *= dp->mp_pages;
iov[n].iov_base = (char *)dp;
size += iov[n].iov_len;
next = dp->mp_pgno + (IS_OVERFLOW(dp) ? dp->mp_pages : 1);
/* clear dirty flag */
dp->mp_flags &= ~P_DIRTY;
if (++n >= MDB_COMMIT_PAGES) {
done = 0;
i++;
break;
}
}
if (n == 0)
break;
rc = writev(env->me_fd, iov, n);
if (rc != size) {
n = ErrCode();
if (rc > 0)
DPUTS("short write, filesystem full?");
else
DPRINTF("writev: %s", strerror(n));
mdb_txn_abort(txn);
return n;
}
#endif
} while (!done);
/* Drop the dirty pages.
*/
for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
dp = txn->mt_u.dirty_list[i].mptr;
if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
dp->mp_next = txn->mt_env->me_dpages;
VGMEMP_FREE(txn->mt_env, dp);
txn->mt_env->me_dpages = dp;
} else {
VGMEMP_FREE(txn->mt_env, dp);
free(dp);
}
txn->mt_u.dirty_list[i].mid = 0;
}
txn->mt_u.dirty_list[0].mid = 0;
sync:
if ((n = mdb_env_sync(env, 0)) != 0 ||
(n = mdb_env_write_meta(txn)) != MDB_SUCCESS) {
mdb_txn_abort(txn);
return n;
}
done:
env->me_txn = NULL;
if (txn->mt_numdbs > env->me_numdbs) {
/* update the DB flags */
MDB_dbi i;
for (i = env->me_numdbs; i<txn->mt_numdbs; i++)
env->me_dbflags[i] = txn->mt_dbs[i].md_flags;
env->me_numdbs = i;
}
UNLOCK_MUTEX_W(env);
free(txn);
return MDB_SUCCESS;
}
/** Read the environment parameters of a DB environment before
* mapping it into memory.
* @param[in] env the environment handle
* @param[out] meta address of where to store the meta information
* @return 0 on success, non-zero on failure.
*/
static int
mdb_env_read_header(MDB_env *env, MDB_meta *meta)
{
MDB_pagebuf pbuf;
MDB_page *p;
MDB_meta *m;
int rc, err;
/* We don't know the page size yet, so use a minimum value.
*/
#ifdef _WIN32
if (!ReadFile(env->me_fd, &pbuf, MDB_PAGESIZE, (DWORD *)&rc, NULL) || rc == 0)
#else
if ((rc = read(env->me_fd, &pbuf, MDB_PAGESIZE)) == 0)
#endif
{
return ENOENT;
}
else if (rc != MDB_PAGESIZE) {
err = ErrCode();
if (rc > 0)
err = MDB_INVALID;
DPRINTF("read: %s", strerror(err));
return err;
}
p = (MDB_page *)&pbuf;
if (!F_ISSET(p->mp_flags, P_META)) {
DPRINTF("page %zu not a meta page", p->mp_pgno);
return MDB_INVALID;
}
m = METADATA(p);
if (m->mm_magic != MDB_MAGIC) {
DPUTS("meta has invalid magic");
return MDB_INVALID;
}
if (m->mm_version != MDB_VERSION) {
DPRINTF("database is version %u, expected version %u",
m->mm_version, MDB_VERSION);
return MDB_VERSION_MISMATCH;
}
memcpy(meta, m, sizeof(*m));
return 0;
}
/** Write the environment parameters of a freshly created DB environment.
* @param[in] env the environment handle
* @param[out] meta address of where to store the meta information
* @return 0 on success, non-zero on failure.
*/
static int
mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
{
MDB_page *p, *q;
MDB_meta *m;
int rc;
unsigned int psize;
DPUTS("writing new meta page");
GET_PAGESIZE(psize);
meta->mm_magic = MDB_MAGIC;
meta->mm_version = MDB_VERSION;
meta->mm_psize = psize;
meta->mm_last_pg = 1;
meta->mm_flags = env->me_flags & 0xffff;
meta->mm_flags |= MDB_INTEGERKEY;
meta->mm_dbs[0].md_root = P_INVALID;
meta->mm_dbs[1].md_root = P_INVALID;
p = calloc(2, psize);
p->mp_pgno = 0;
p->mp_flags = P_META;
m = METADATA(p);
memcpy(m, meta, sizeof(*meta));
q = (MDB_page *)((char *)p + psize);
q->mp_pgno = 1;
q->mp_flags = P_META;
m = METADATA(q);
memcpy(m, meta, sizeof(*meta));
#ifdef _WIN32
{
DWORD len;
rc = WriteFile(env->me_fd, p, psize * 2, &len, NULL);
rc = (len == psize * 2) ? MDB_SUCCESS : ErrCode();
}
#else
rc = write(env->me_fd, p, psize * 2);
rc = (rc == (int)psize * 2) ? MDB_SUCCESS : ErrCode();
#endif
free(p);
return rc;
}
/** Update the environment info to commit a transaction.
* @param[in] txn the transaction that's being committed
* @return 0 on success, non-zero on failure.
*/
static int
mdb_env_write_meta(MDB_txn *txn)
{
MDB_env *env;
MDB_meta meta, metab;
off_t off;
int rc, len, toggle;
char *ptr;
#ifdef _WIN32
OVERLAPPED ov;
#endif
assert(txn != NULL);
assert(txn->mt_env != NULL);
toggle = !txn->mt_toggle;
DPRINTF("writing meta page %d for root page %zu",
toggle, txn->mt_dbs[MAIN_DBI].md_root);
env = txn->mt_env;
if (env->me_flags & MDB_WRITEMAP) {
MDB_meta *mp = env->me_metas[toggle];
mp->mm_dbs[0] = txn->mt_dbs[0];
mp->mm_dbs[1] = txn->mt_dbs[1];
mp->mm_last_pg = txn->mt_next_pgno - 1;
mp->mm_txnid = txn->mt_txnid;
if (!(env->me_flags & (MDB_NOMETASYNC|MDB_NOSYNC))) {
rc = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
ptr = env->me_map;
if (toggle)
ptr += env->me_psize;
if (MDB_MSYNC(ptr, env->me_psize, rc)) {
rc = ErrCode();
goto fail;
}
}
goto done;
}
metab.mm_txnid = env->me_metas[toggle]->mm_txnid;
metab.mm_last_pg = env->me_metas[toggle]->mm_last_pg;
ptr = (char *)&meta;
off = offsetof(MDB_meta, mm_dbs[0].md_depth);
len = sizeof(MDB_meta) - off;
ptr += off;
meta.mm_dbs[0] = txn->mt_dbs[0];
meta.mm_dbs[1] = txn->mt_dbs[1];
meta.mm_last_pg = txn->mt_next_pgno - 1;
meta.mm_txnid = txn->mt_txnid;
if (toggle)
off += env->me_psize;
off += PAGEHDRSZ;
/* Write to the SYNC fd */
#ifdef _WIN32
{
memset(&ov, 0, sizeof(ov));
ov.Offset = off;
WriteFile(env->me_mfd, ptr, len, (DWORD *)&rc, &ov);
}
#else
rc = pwrite(env->me_mfd, ptr, len, off);
#endif
if (rc != len) {
int r2;
rc = ErrCode();
DPUTS("write failed, disk error?");
/* On a failure, the pagecache still contains the new data.
* Write some old data back, to prevent it from being used.
* Use the non-SYNC fd; we know it will fail anyway.
*/
meta.mm_last_pg = metab.mm_last_pg;
meta.mm_txnid = metab.mm_txnid;
#ifdef _WIN32
WriteFile(env->me_fd, ptr, len, NULL, &ov);
#else
r2 = pwrite(env->me_fd, ptr, len, off);
#endif
fail:
env->me_flags |= MDB_FATAL_ERROR;
return rc;
}
done:
/* Memory ordering issues are irrelevant; since the entire writer
* is wrapped by wmutex, all of these changes will become visible
* after the wmutex is unlocked. Since the DB is multi-version,
* readers will get consistent data regardless of how fresh or
* how stale their view of these values is.
*/
txn->mt_env->me_txns->mti_txnid = txn->mt_txnid;
return MDB_SUCCESS;
}
/** Check both meta pages to see which one is newer.
* @param[in] env the environment handle
* @return meta toggle (0 or 1).
*/
static int
mdb_env_pick_meta(const MDB_env *env)
{
return (env->me_metas[0]->mm_txnid < env->me_metas[1]->mm_txnid);
}
int
mdb_env_create(MDB_env **env)
{
MDB_env *e;
e = calloc(1, sizeof(MDB_env));
if (!e)
return ENOMEM;
e->me_free_pgs = mdb_midl_alloc();
if (!e->me_free_pgs) {
free(e);
return ENOMEM;
}
e->me_maxreaders = DEFAULT_READERS;
e->me_maxdbs = 2;
e->me_fd = INVALID_HANDLE_VALUE;
e->me_lfd = INVALID_HANDLE_VALUE;
e->me_mfd = INVALID_HANDLE_VALUE;
#ifdef MDB_USE_POSIX_SEM
e->me_rmutex = SEM_FAILED;
e->me_wmutex = SEM_FAILED;
#endif
e->me_pid = getpid();
VGMEMP_CREATE(e,0,0);
*env = e;
return MDB_SUCCESS;
}
int
mdb_env_set_mapsize(MDB_env *env, size_t size)
{
if (env->me_map)
return EINVAL;
env->me_mapsize = size;
if (env->me_psize)
env->me_maxpg = env->me_mapsize / env->me_psize;
return MDB_SUCCESS;
}
int
mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs)
{
if (env->me_map)
return EINVAL;
env->me_maxdbs = dbs;
return MDB_SUCCESS;
}
int
mdb_env_set_maxreaders(MDB_env *env, unsigned int readers)
{
if (env->me_map || readers < 1)
return EINVAL;
env->me_maxreaders = readers;
return MDB_SUCCESS;
}
int
mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)
{
if (!env || !readers)
return EINVAL;
*readers = env->me_maxreaders;
return MDB_SUCCESS;
}
/** Further setup required for opening an MDB environment
*/
static int
mdb_env_open2(MDB_env *env, unsigned int flags)
{
int i, newenv = 0, prot;
MDB_meta meta;
MDB_page *p;
env->me_flags = flags;
memset(&meta, 0, sizeof(meta));
if ((i = mdb_env_read_header(env, &meta)) != 0) {
if (i != ENOENT)
return i;
DPUTS("new mdbenv");
newenv = 1;
}
if (!env->me_mapsize) {
env->me_mapsize = newenv ? DEFAULT_MAPSIZE : meta.mm_mapsize;
}
#ifdef _WIN32
{
HANDLE mh;
LONG sizelo, sizehi;
sizelo = env->me_mapsize & 0xffffffff;
sizehi = env->me_mapsize >> 16; /* pointless on WIN32, only needed on W64 */
sizehi >>= 16;
/* Windows won't create mappings for zero length files.
* Just allocate the maxsize right now.
*/
if (newenv) {
SetFilePointer(env->me_fd, sizelo, sizehi ? &sizehi : NULL, 0);
if (!SetEndOfFile(env->me_fd))
return ErrCode();
SetFilePointer(env->me_fd, 0, NULL, 0);
}
mh = CreateFileMapping(env->me_fd, NULL, flags & MDB_WRITEMAP ?
PAGE_READWRITE : PAGE_READONLY,
sizehi, sizelo, NULL);
if (!mh)
return ErrCode();
env->me_map = MapViewOfFileEx(mh, flags & MDB_WRITEMAP ?
FILE_MAP_WRITE : FILE_MAP_READ,
0, 0, env->me_mapsize, meta.mm_address);
CloseHandle(mh);
if (!env->me_map)
return ErrCode();
}
#else
i = MAP_SHARED;
if (meta.mm_address && (flags & MDB_FIXEDMAP))
i |= MAP_FIXED;
prot = PROT_READ;
if (flags & MDB_WRITEMAP) {
prot |= PROT_WRITE;
ftruncate(env->me_fd, env->me_mapsize);
}
env->me_map = mmap(meta.mm_address, env->me_mapsize, prot, i,
env->me_fd, 0);
if (env->me_map == MAP_FAILED) {
env->me_map = NULL;
return ErrCode();
}
#endif
if (newenv) {
meta.mm_mapsize = env->me_mapsize;
if (flags & MDB_FIXEDMAP)
meta.mm_address = env->me_map;
i = mdb_env_init_meta(env, &meta);
if (i != MDB_SUCCESS) {
return i;
}
}
env->me_psize = meta.mm_psize;
env->me_maxpg = env->me_mapsize / env->me_psize;
p = (MDB_page *)env->me_map;
env->me_metas[0] = METADATA(p);
env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + meta.mm_psize);
#if MDB_DEBUG
{
int toggle = mdb_env_pick_meta(env);
MDB_db *db = &env->me_metas[toggle]->mm_dbs[MAIN_DBI];
DPRINTF("opened database version %u, pagesize %u",
env->me_metas[0]->mm_version, env->me_psize);
DPRINTF("using meta page %d", toggle);
DPRINTF("depth: %u", db->md_depth);
DPRINTF("entries: %zu", db->md_entries);
DPRINTF("branch pages: %zu", db->md_branch_pages);
DPRINTF("leaf pages: %zu", db->md_leaf_pages);
DPRINTF("overflow pages: %zu", db->md_overflow_pages);
DPRINTF("root: %zu", db->md_root);
}
#endif
return MDB_SUCCESS;
}
/** Release a reader thread's slot in the reader lock table.
* This function is called automatically when a thread exits.
* @param[in] ptr This points to the slot in the reader lock table.
*/
static void
mdb_env_reader_dest(void *ptr)
{
MDB_reader *reader = ptr;
reader->mr_pid = 0;
}
#ifdef _WIN32
/** Junk for arranging thread-specific callbacks on Windows. This is
* necessarily platform and compiler-specific. Windows supports up
* to 1088 keys. Let's assume nobody opens more than 64 environments
* in a single process, for now. They can override this if needed.
*/
#ifndef MAX_TLS_KEYS
#define MAX_TLS_KEYS 64
#endif
static pthread_key_t mdb_tls_keys[MAX_TLS_KEYS];
static int mdb_tls_nkeys;
static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)
{
int i;
switch(reason) {
case DLL_PROCESS_ATTACH: break;
case DLL_THREAD_ATTACH: break;
case DLL_THREAD_DETACH:
for (i=0; i<mdb_tls_nkeys; i++) {
MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);
mdb_env_reader_dest(r);
}
break;
case DLL_PROCESS_DETACH: break;
}
}
#ifdef __GNUC__
#ifdef _WIN64
const PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
#else
PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
#endif
#else
#ifdef _WIN64
/* Force some symbol references.
* _tls_used forces the linker to create the TLS directory if not already done
* mdb_tls_cbp prevents whole-program-optimizer from dropping the symbol.
*/
#pragma comment(linker, "/INCLUDE:_tls_used")
#pragma comment(linker, "/INCLUDE:mdb_tls_cbp")
#pragma const_seg(".CRT$XLB")
extern const PIMAGE_TLS_CALLBACK mdb_tls_callback;
const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
#pragma const_seg()
#else /* WIN32 */
#pragma comment(linker, "/INCLUDE:__tls_used")
#pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")
#pragma data_seg(".CRT$XLB")
PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
#pragma data_seg()
#endif /* WIN 32/64 */
#endif /* !__GNUC__ */
#endif
/** Downgrade the exclusive lock on the region back to shared */
static int
mdb_env_share_locks(MDB_env *env, int *excl)
{
int rc = 0, toggle = mdb_env_pick_meta(env);
env->me_txns->mti_txnid = env->me_metas[toggle]->mm_txnid;
#ifdef _WIN32
{
OVERLAPPED ov;
/* First acquire a shared lock. The Unlock will
* then release the existing exclusive lock.
*/
memset(&ov, 0, sizeof(ov));
LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov);
UnlockFile(env->me_lfd, 0, 0, 1, 0);
*excl = 0;
}
#else
{
struct flock lock_info;
/* The shared lock replaces the existing lock */
memset((void *)&lock_info, 0, sizeof(lock_info));
lock_info.l_type = F_RDLCK;
lock_info.l_whence = SEEK_SET;
lock_info.l_start = 0;
lock_info.l_len = 1;
while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
(rc = ErrCode()) == EINTR) ;
*excl = rc ? -1 : 0; /* error may mean we lost the lock */
}
#endif
return rc;
}
/** Try to get exlusive lock, otherwise shared.
* Maintain *excl = -1: no/unknown lock, 0: shared, 1: exclusive.
*/
static int
mdb_env_excl_lock(MDB_env *env, int *excl)
{
int rc = 0;
#ifdef _WIN32
if (LockFile(env->me_lfd, 0, 0, 1, 0)) {
*excl = 1;
} else {
OVERLAPPED ov;
memset(&ov, 0, sizeof(ov));
if (!LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
rc = ErrCode();
}
}
#else
struct flock lock_info;
memset((void *)&lock_info, 0, sizeof(lock_info));
lock_info.l_type = F_WRLCK;
lock_info.l_whence = SEEK_SET;
lock_info.l_start = 0;
lock_info.l_len = 1;
if (!fcntl(env->me_lfd, F_SETLK, &lock_info)) {
*excl = 1;
} else
# ifdef MDB_USE_POSIX_SEM
if (*excl < 0) /* always true when !MDB_USE_POSIX_SEM */
# endif
{
lock_info.l_type = F_RDLCK;
while ((rc = fcntl(env->me_lfd, F_SETLKW, &lock_info)) &&
(rc = ErrCode()) == EINTR) ;
if (rc == 0)
*excl = 0;
}
#endif
return rc;
}
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
/*
* hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code
*
* @(#) $Revision: 5.1 $
* @(#) $Id: hash_64a.c,v 5.1 2009/06/30 09:01:38 chongo Exp $
* @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_64a.c,v $
*
* http://www.isthe.com/chongo/tech/comp/fnv/index.html
*
***
*
* Please do not copyright this code. This code is in the public domain.
*
* LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
* EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*
* By:
* chongo <Landon Curt Noll> /\oo/\
* http://www.isthe.com/chongo/
*
* Share and Enjoy! :-)
*/
typedef unsigned long long mdb_hash_t;
#define MDB_HASH_INIT ((mdb_hash_t)0xcbf29ce484222325ULL)
/** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer
* @param[in] str string to hash
* @param[in] hval initial value for hash
* @return 64 bit hash
*
* NOTE: To use the recommended 64 bit FNV-1a hash, use MDB_HASH_INIT as the
* hval arg on the first call.
*/
static mdb_hash_t
mdb_hash_val(MDB_val *val, mdb_hash_t hval)
{
unsigned char *s = (unsigned char *)val->mv_data; /* unsigned string */
unsigned char *end = s + val->mv_size;
/*
* FNV-1a hash each octet of the string
*/
while (s < end) {
/* xor the bottom with the current octet */
hval ^= (mdb_hash_t)*s++;
/* multiply by the 64 bit FNV magic prime mod 2^64 */
hval += (hval << 1) + (hval << 4) + (hval << 5) +
(hval << 7) + (hval << 8) + (hval << 40);
}
/* return our new hash value */
return hval;
}
/** Hash the string and output the hash in hex.
* @param[in] str string to hash
* @param[out] hexbuf an array of 17 chars to hold the hash
*/
static void
mdb_hash_hex(MDB_val *val, char *hexbuf)
{
int i;
mdb_hash_t h = mdb_hash_val(val, MDB_HASH_INIT);
for (i=0; i<8; i++) {
hexbuf += sprintf(hexbuf, "%02x", (unsigned int)h & 0xff);
h >>= 8;
}
}
#endif
/** Open and/or initialize the lock region for the environment.
* @param[in] env The MDB environment.
* @param[in] lpath The pathname of the file used for the lock region.
* @param[in] mode The Unix permissions for the file, if we create it.
* @param[out] excl Resulting file lock type: -1 none, 0 shared, 1 exclusive
* @return 0 on success, non-zero on failure.
*/
static int
mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
{
int rc;
off_t size, rsize;
*excl = -1;
#ifdef _WIN32
if ((env->me_lfd = CreateFile(lpath, GENERIC_READ|GENERIC_WRITE,
FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL, NULL)) == INVALID_HANDLE_VALUE) {
goto fail_errno;
}
/* Try to get exclusive lock. If we succeed, then
* nobody is using the lock region and we should initialize it.
*/
if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
size = GetFileSize(env->me_lfd, NULL);
#else
#if !(O_CLOEXEC)
{
int fdflags;
if ((env->me_lfd = open(lpath, O_RDWR|O_CREAT, mode)) == -1)
goto fail_errno;
/* Lose record locks when exec*() */
if ((fdflags = fcntl(env->me_lfd, F_GETFD) | FD_CLOEXEC) >= 0)
fcntl(env->me_lfd, F_SETFD, fdflags);
}
#else /* O_CLOEXEC on Linux: Open file and set FD_CLOEXEC atomically */
if ((env->me_lfd = open(lpath, O_RDWR|O_CREAT|O_CLOEXEC, mode)) == -1)
goto fail_errno;
#endif
/* Try to get exclusive lock. If we succeed, then
* nobody is using the lock region and we should initialize it.
*/
if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
size = lseek(env->me_lfd, 0, SEEK_END);
#endif
rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
if (size < rsize && *excl > 0) {
#ifdef _WIN32
SetFilePointer(env->me_lfd, rsize, NULL, 0);
if (!SetEndOfFile(env->me_lfd)) goto fail_errno;
#else
if (ftruncate(env->me_lfd, rsize) != 0) goto fail_errno;
#endif
} else {
rsize = size;
size = rsize - sizeof(MDB_txninfo);
env->me_maxreaders = size/sizeof(MDB_reader) + 1;
}
{
#ifdef _WIN32
HANDLE mh;
mh = CreateFileMapping(env->me_lfd, NULL, PAGE_READWRITE,
0, 0, NULL);
if (!mh) goto fail_errno;
env->me_txns = MapViewOfFileEx(mh, FILE_MAP_WRITE, 0, 0, rsize, NULL);
CloseHandle(mh);
if (!env->me_txns) goto fail_errno;
#else
void *m = mmap(NULL, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,
env->me_lfd, 0);
if (m == MAP_FAILED) goto fail_errno;
env->me_txns = m;
#endif
}
if (*excl > 0) {
#ifdef _WIN32
BY_HANDLE_FILE_INFORMATION stbuf;
struct {
DWORD volume;
DWORD nhigh;
DWORD nlow;
} idbuf;
MDB_val val;
char hexbuf[17];
if (!mdb_sec_inited) {
InitializeSecurityDescriptor(&mdb_null_sd,
SECURITY_DESCRIPTOR_REVISION);
SetSecurityDescriptorDacl(&mdb_null_sd, TRUE, 0, FALSE);
mdb_all_sa.nLength = sizeof(SECURITY_ATTRIBUTES);
mdb_all_sa.bInheritHandle = FALSE;
mdb_all_sa.lpSecurityDescriptor = &mdb_null_sd;
mdb_sec_inited = 1;
}
GetFileInformationByHandle(env->me_lfd, &stbuf);
idbuf.volume = stbuf.dwVolumeSerialNumber;
idbuf.nhigh = stbuf.nFileIndexHigh;
idbuf.nlow = stbuf.nFileIndexLow;
val.mv_data = &idbuf;
val.mv_size = sizeof(idbuf);
mdb_hash_hex(&val, hexbuf);
sprintf(env->me_txns->mti_rmname, "Global\\MDBr%s", hexbuf);
sprintf(env->me_txns->mti_wmname, "Global\\MDBw%s", hexbuf);
env->me_rmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);
if (!env->me_rmutex) goto fail_errno;
env->me_wmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_wmname);
if (!env->me_wmutex) goto fail_errno;
#elif defined(MDB_USE_POSIX_SEM)
struct stat stbuf;
struct {
dev_t dev;
ino_t ino;
} idbuf;
MDB_val val;
char hexbuf[17];
if (fstat(env->me_lfd, &stbuf)) goto fail_errno;
idbuf.dev = stbuf.st_dev;
idbuf.ino = stbuf.st_ino;
val.mv_data = &idbuf;
val.mv_size = sizeof(idbuf);
mdb_hash_hex(&val, hexbuf);
sprintf(env->me_txns->mti_rmname, "/MDBr%s", hexbuf);
sprintf(env->me_txns->mti_wmname, "/MDBw%s", hexbuf);
/* Clean up after a previous run, if needed: Try to
* remove both semaphores before doing anything else.
*/
sem_unlink(env->me_txns->mti_rmname);
sem_unlink(env->me_txns->mti_wmname);
env->me_rmutex = sem_open(env->me_txns->mti_rmname,
O_CREAT|O_EXCL, mode, 1);
if (env->me_rmutex == SEM_FAILED) goto fail_errno;
env->me_wmutex = sem_open(env->me_txns->mti_wmname,
O_CREAT|O_EXCL, mode, 1);
if (env->me_wmutex == SEM_FAILED) goto fail_errno;
#else /* MDB_USE_POSIX_SEM */
pthread_mutexattr_t mattr;
if ((rc = pthread_mutexattr_init(&mattr))
|| (rc = pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED))
|| (rc = pthread_mutex_init(&env->me_txns->mti_mutex, &mattr))
|| (rc = pthread_mutex_init(&env->me_txns->mti_wmutex, &mattr)))
goto fail;
pthread_mutexattr_destroy(&mattr);
#endif /* _WIN32 || MDB_USE_POSIX_SEM */
env->me_txns->mti_version = MDB_VERSION;
env->me_txns->mti_magic = MDB_MAGIC;
env->me_txns->mti_txnid = 0;
env->me_txns->mti_numreaders = 0;
} else {
if (env->me_txns->mti_magic != MDB_MAGIC) {
DPUTS("lock region has invalid magic");
rc = MDB_INVALID;
goto fail;
}
if (env->me_txns->mti_version != MDB_VERSION) {
DPRINTF("lock region is version %u, expected version %u",
env->me_txns->mti_version, MDB_VERSION);
rc = MDB_VERSION_MISMATCH;
goto fail;
}
rc = ErrCode();
if (rc != EACCES && rc != EAGAIN) {
goto fail;
}
#ifdef _WIN32
env->me_rmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_rmname);
if (!env->me_rmutex) goto fail_errno;
env->me_wmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_wmname);
if (!env->me_wmutex) goto fail_errno;
#elif defined(MDB_USE_POSIX_SEM)
env->me_rmutex = sem_open(env->me_txns->mti_rmname, 0);
if (env->me_rmutex == SEM_FAILED) goto fail_errno;
env->me_wmutex = sem_open(env->me_txns->mti_wmname, 0);
if (env->me_wmutex == SEM_FAILED) goto fail_errno;
#endif
}
return MDB_SUCCESS;
fail_errno:
rc = ErrCode();
fail:
return rc;
}
/** The name of the lock file in the DB environment */
#define LOCKNAME "/lock.mdb"
/** The name of the data file in the DB environment */
#define DATANAME "/data.mdb"
/** The suffix of the lock file when no subdir is used */
#define LOCKSUFF "-lock"
int
mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mode_t mode)
{
int oflags, rc, len, excl;
char *lpath, *dpath;
if (env->me_fd != INVALID_HANDLE_VALUE)
return EINVAL;
len = strlen(path);
if (flags & MDB_NOSUBDIR) {
rc = len + sizeof(LOCKSUFF) + len + 1;
} else {
rc = len + sizeof(LOCKNAME) + len + sizeof(DATANAME);
}
lpath = malloc(rc);
if (!lpath)
return ENOMEM;
if (flags & MDB_NOSUBDIR) {
dpath = lpath + len + sizeof(LOCKSUFF);
sprintf(lpath, "%s" LOCKSUFF, path);
strcpy(dpath, path);
} else {
dpath = lpath + len + sizeof(LOCKNAME);
sprintf(lpath, "%s" LOCKNAME, path);
sprintf(dpath, "%s" DATANAME, path);
}
rc = mdb_env_setup_locks(env, lpath, mode, &excl);
if (rc)
goto leave;
/* silently ignore WRITEMAP if we're only getting read access */
if (F_ISSET(flags, MDB_RDONLY) && F_ISSET(flags, MDB_WRITEMAP))
flags ^= MDB_WRITEMAP;
#ifdef _WIN32
if (F_ISSET(flags, MDB_RDONLY)) {
oflags = GENERIC_READ;
len = OPEN_EXISTING;
} else {
oflags = GENERIC_READ|GENERIC_WRITE;
len = OPEN_ALWAYS;
}
mode = FILE_ATTRIBUTE_NORMAL;
env->me_fd = CreateFile(dpath, oflags, FILE_SHARE_READ|FILE_SHARE_WRITE,
NULL, len, mode, NULL);
#else
if (F_ISSET(flags, MDB_RDONLY))
oflags = O_RDONLY;
else
oflags = O_RDWR | O_CREAT;
env->me_fd = open(dpath, oflags, mode);
#endif
if (env->me_fd == INVALID_HANDLE_VALUE) {
rc = ErrCode();
goto leave;
}
if ((rc = mdb_env_open2(env, flags)) == MDB_SUCCESS) {
if (flags & (MDB_RDONLY|MDB_NOSYNC|MDB_NOMETASYNC|MDB_WRITEMAP)) {
env->me_mfd = env->me_fd;
} else {
/* synchronous fd for meta writes */
#ifdef _WIN32
env->me_mfd = CreateFile(dpath, oflags,
FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, len,
mode | FILE_FLAG_WRITE_THROUGH, NULL);
#else
env->me_mfd = open(dpath, oflags | MDB_DSYNC, mode);
#endif
if (env->me_mfd == INVALID_HANDLE_VALUE) {
rc = ErrCode();
goto leave;
}
}
DPRINTF("opened dbenv %p", (void *) env);
pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
env->me_numdbs = 2; /* this notes that me_txkey was set */
#ifdef _WIN32
/* Windows TLS callbacks need help finding their TLS info. */
if (mdb_tls_nkeys < MAX_TLS_KEYS)
mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;
else {
rc = MDB_TLS_FULL;
goto leave;
}
#endif
if (excl > 0) {
rc = mdb_env_share_locks(env, &excl);
if (rc)
goto leave;
}
env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));
env->me_path = strdup(path);
if (!env->me_dbxs || !env->me_dbflags || !env->me_path)
rc = ENOMEM;
}
leave:
if (rc) {
mdb_env_close0(env, excl);
}
free(lpath);
return rc;
}
/** Destroy resources from mdb_env_open() and clear our readers */
static void
mdb_env_close0(MDB_env *env, int excl)
{
int i;
if (env->me_lfd == INVALID_HANDLE_VALUE) /* 1st field to get inited */
return;
free(env->me_dbflags);
free(env->me_dbxs);
free(env->me_path);
if (env->me_numdbs) {
pthread_key_delete(env->me_txkey);
#ifdef _WIN32
/* Delete our key from the global list */
for (i=0; i<mdb_tls_nkeys; i++)
if (mdb_tls_keys[i] == env->me_txkey) {
mdb_tls_keys[i] = mdb_tls_keys[mdb_tls_nkeys-1];
mdb_tls_nkeys--;
break;
}
#endif
}
if (env->me_map) {
munmap(env->me_map, env->me_mapsize);
}
if (env->me_mfd != env->me_fd && env->me_mfd != INVALID_HANDLE_VALUE)
close(env->me_mfd);
if (env->me_fd != INVALID_HANDLE_VALUE)
close(env->me_fd);
if (env->me_txns) {
pid_t pid = env->me_pid;
/* Clearing readers is done in this function because
* me_txkey with its destructor must be disabled first.
*/
for (i = env->me_numreaders; --i >= 0; )
if (env->me_txns->mti_readers[i].mr_pid == pid)
env->me_txns->mti_readers[i].mr_pid = 0;
#ifdef _WIN32
if (env->me_rmutex) {
CloseHandle(env->me_rmutex);
if (env->me_wmutex) CloseHandle(env->me_wmutex);
}
/* Windows automatically destroys the mutexes when
* the last handle closes.
*/
#elif defined(MDB_USE_POSIX_SEM)
if (env->me_rmutex != SEM_FAILED) {
sem_close(env->me_rmutex);
if (env->me_wmutex != SEM_FAILED)
sem_close(env->me_wmutex);
/* If we have the filelock: If we are the
* only remaining user, clean up semaphores.
*/
if (excl == 0)
mdb_env_excl_lock(env, &excl);
if (excl > 0) {
sem_unlink(env->me_txns->mti_rmname);
sem_unlink(env->me_txns->mti_wmname);
}
}
#endif
munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
}
close(env->me_lfd);
env->me_lfd = INVALID_HANDLE_VALUE; /* Mark env as reset */
}
void
mdb_env_close(MDB_env *env)
{
MDB_page *dp;
if (env == NULL)
return;
VGMEMP_DESTROY(env);
while ((dp = env->me_dpages) != NULL) {
VGMEMP_DEFINED(&dp->mp_next, sizeof(dp->mp_next));
env->me_dpages = dp->mp_next;
free(dp);
}
mdb_env_close0(env, 0);
mdb_midl_free(env->me_free_pgs);
free(env);
}
/** Compare two items pointing at aligned size_t's */
static int
mdb_cmp_long(const MDB_val *a, const MDB_val *b)
{
return (*(size_t *)a->mv_data < *(size_t *)b->mv_data) ? -1 :
*(size_t *)a->mv_data > *(size_t *)b->mv_data;
}
/** Compare two items pointing at aligned int's */
static int
mdb_cmp_int(const MDB_val *a, const MDB_val *b)
{
return (*(unsigned int *)a->mv_data < *(unsigned int *)b->mv_data) ? -1 :
*(unsigned int *)a->mv_data > *(unsigned int *)b->mv_data;
}
/** Compare two items pointing at ints of unknown alignment.
* Nodes and keys are guaranteed to be 2-byte aligned.
*/
static int
mdb_cmp_cint(const MDB_val *a, const MDB_val *b)
{
#if BYTE_ORDER == LITTLE_ENDIAN
unsigned short *u, *c;
int x;
u = (unsigned short *) ((char *) a->mv_data + a->mv_size);
c = (unsigned short *) ((char *) b->mv_data + a->mv_size);
do {
x = *--u - *--c;
} while(!x && u > (unsigned short *)a->mv_data);
return x;
#else
return memcmp(a->mv_data, b->mv_data, a->mv_size);
#endif
}
/** Compare two items lexically */
static int
mdb_cmp_memn(const MDB_val *a, const MDB_val *b)
{
int diff;
ssize_t len_diff;
unsigned int len;
len = a->mv_size;
len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
if (len_diff > 0) {
len = b->mv_size;
len_diff = 1;
}
diff = memcmp(a->mv_data, b->mv_data, len);
return diff ? diff : len_diff<0 ? -1 : len_diff;
}
/** Compare two items in reverse byte order */
static int
mdb_cmp_memnr(const MDB_val *a, const MDB_val *b)
{
const unsigned char *p1, *p2, *p1_lim;
ssize_t len_diff;
int diff;
p1_lim = (const unsigned char *)a->mv_data;
p1 = (const unsigned char *)a->mv_data + a->mv_size;
p2 = (const unsigned char *)b->mv_data + b->mv_size;
len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
if (len_diff > 0) {
p1_lim += len_diff;
len_diff = 1;
}
while (p1 > p1_lim) {
diff = *--p1 - *--p2;
if (diff)
return diff;
}
return len_diff<0 ? -1 : len_diff;
}
/** Search for key within a page, using binary search.
* Returns the smallest entry larger or equal to the key.
* If exactp is non-null, stores whether the found entry was an exact match
* in *exactp (1 or 0).
* Updates the cursor index with the index of the found entry.
* If no entry larger or equal to the key is found, returns NULL.
*/
static MDB_node *
mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp)
{
unsigned int i = 0, nkeys;
int low, high;
int rc = 0;
MDB_page *mp = mc->mc_pg[mc->mc_top];
MDB_node *node = NULL;
MDB_val nodekey;
MDB_cmp_func *cmp;
DKBUF;
nkeys = NUMKEYS(mp);
#if MDB_DEBUG
{
pgno_t pgno;
COPY_PGNO(pgno, mp->mp_pgno);
DPRINTF("searching %u keys in %s %spage %zu",
nkeys, IS_LEAF(mp) ? "leaf" : "branch", IS_SUBP(mp) ? "sub-" : "",
pgno);
}
#endif
assert(nkeys > 0);
low = IS_LEAF(mp) ? 0 : 1;
high = nkeys - 1;
cmp = mc->mc_dbx->md_cmp;
/* Branch pages have no data, so if using integer keys,
* alignment is guaranteed. Use faster mdb_cmp_int.
*/
if (cmp == mdb_cmp_cint && IS_BRANCH(mp)) {
if (NODEPTR(mp, 1)->mn_ksize == sizeof(size_t))
cmp = mdb_cmp_long;
else
cmp = mdb_cmp_int;
}
if (IS_LEAF2(mp)) {
nodekey.mv_size = mc->mc_db->md_pad;
node = NODEPTR(mp, 0); /* fake */
while (low <= high) {
i = (low + high) >> 1;
nodekey.mv_data = LEAF2KEY(mp, i, nodekey.mv_size);
rc = cmp(key, &nodekey);
DPRINTF("found leaf index %u [%s], rc = %i",
i, DKEY(&nodekey), rc);
if (rc == 0)
break;
if (rc > 0)
low = i + 1;
else
high = i - 1;
}
} else {
while (low <= high) {
i = (low + high) >> 1;
node = NODEPTR(mp, i);
nodekey.mv_size = NODEKSZ(node);
nodekey.mv_data = NODEKEY(node);
rc = cmp(key, &nodekey);
#if MDB_DEBUG
if (IS_LEAF(mp))
DPRINTF("found leaf index %u [%s], rc = %i",
i, DKEY(&nodekey), rc);
else
DPRINTF("found branch index %u [%s -> %zu], rc = %i",
i, DKEY(&nodekey), NODEPGNO(node), rc);
#endif
if (rc == 0)
break;
if (rc > 0)
low = i + 1;
else
high = i - 1;
}
}
if (rc > 0) { /* Found entry is less than the key. */
i++; /* Skip to get the smallest entry larger than key. */
if (!IS_LEAF2(mp))
node = NODEPTR(mp, i);
}
if (exactp)
*exactp = (rc == 0);
/* store the key index */
mc->mc_ki[mc->mc_top] = i;
if (i >= nkeys)
/* There is no entry larger or equal to the key. */
return NULL;
/* nodeptr is fake for LEAF2 */
return node;
}
#if 0
static void
mdb_cursor_adjust(MDB_cursor *mc, func)
{
MDB_cursor *m2;
for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
if (m2->mc_pg[m2->mc_top] == mc->mc_pg[mc->mc_top]) {
func(mc, m2);
}
}
}
#endif
/** Pop a page off the top of the cursor's stack. */
static void
mdb_cursor_pop(MDB_cursor *mc)
{
if (mc->mc_snum) {
#if MDB_DEBUG
MDB_page *top = mc->mc_pg[mc->mc_top];
#endif
mc->mc_snum--;
if (mc->mc_snum)
mc->mc_top--;
DPRINTF("popped page %zu off db %u cursor %p", top->mp_pgno,
mc->mc_dbi, (void *) mc);
}
}
/** Push a page onto the top of the cursor's stack. */
static int
mdb_cursor_push(MDB_cursor *mc, MDB_page *mp)
{
DPRINTF("pushing page %zu on db %u cursor %p", mp->mp_pgno,
mc->mc_dbi, (void *) mc);
if (mc->mc_snum >= CURSOR_STACK) {
assert(mc->mc_snum < CURSOR_STACK);
return MDB_CURSOR_FULL;
}
mc->mc_top = mc->mc_snum++;
mc->mc_pg[mc->mc_top] = mp;
mc->mc_ki[mc->mc_top] = 0;
return MDB_SUCCESS;
}
/** Find the address of the page corresponding to a given page number.
* @param[in] txn the transaction for this access.
* @param[in] pgno the page number for the page to retrieve.
* @param[out] ret address of a pointer where the page's address will be stored.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_get(MDB_txn *txn, pgno_t pgno, MDB_page **ret)
{
MDB_page *p = NULL;
if (txn->mt_env->me_flags & MDB_WRITEMAP) {
if (pgno < txn->mt_next_pgno)
p = (MDB_page *)(txn->mt_env->me_map + txn->mt_env->me_psize * pgno);
goto done;
}
if (!F_ISSET(txn->mt_flags, MDB_TXN_RDONLY) && txn->mt_u.dirty_list[0].mid) {
unsigned x;
x = mdb_mid2l_search(txn->mt_u.dirty_list, pgno);
if (x <= txn->mt_u.dirty_list[0].mid && txn->mt_u.dirty_list[x].mid == pgno) {
p = txn->mt_u.dirty_list[x].mptr;
}
}
if (!p) {
if (pgno < txn->mt_next_pgno)
p = (MDB_page *)(txn->mt_env->me_map + txn->mt_env->me_psize * pgno);
}
done:
*ret = p;
if (!p) {
DPRINTF("page %zu not found", pgno);
assert(p != NULL);
}
return (p != NULL) ? MDB_SUCCESS : MDB_PAGE_NOTFOUND;
}
/** Search for the page a given key should be in.
* Pushes parent pages on the cursor stack. This function continues a
* search on a cursor that has already been initialized. (Usually by
* #mdb_page_search() but also by #mdb_node_move().)
* @param[in,out] mc the cursor for this operation.
* @param[in] key the key to search for. If NULL, search for the lowest
* page. (This is used by #mdb_cursor_first().)
* @param[in] flags If MDB_PS_MODIFY set, visited pages are updated with new page numbers.
* If MDB_PS_ROOTONLY set, just fetch root node, no further lookups.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_search_root(MDB_cursor *mc, MDB_val *key, int modify)
{
MDB_page *mp = mc->mc_pg[mc->mc_top];
DKBUF;
int rc;
while (IS_BRANCH(mp)) {
MDB_node *node;
indx_t i;
DPRINTF("branch page %zu has %u keys", mp->mp_pgno, NUMKEYS(mp));
assert(NUMKEYS(mp) > 1);
DPRINTF("found index 0 to page %zu", NODEPGNO(NODEPTR(mp, 0)));
if (key == NULL) /* Initialize cursor to first page. */
i = 0;
else if (key->mv_size > MAXKEYSIZE && key->mv_data == NULL) {
/* cursor to last page */
i = NUMKEYS(mp)-1;
} else {
int exact;
node = mdb_node_search(mc, key, &exact);
if (node == NULL)
i = NUMKEYS(mp) - 1;
else {
i = mc->mc_ki[mc->mc_top];
if (!exact) {
assert(i > 0);
i--;
}
}
}
if (key)
DPRINTF("following index %u for key [%s]",
i, DKEY(key));
assert(i < NUMKEYS(mp));
node = NODEPTR(mp, i);
if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mp)))
return rc;
mc->mc_ki[mc->mc_top] = i;
if ((rc = mdb_cursor_push(mc, mp)))
return rc;
if (modify) {
if ((rc = mdb_page_touch(mc)) != 0)
return rc;
mp = mc->mc_pg[mc->mc_top];
}
}
if (!IS_LEAF(mp)) {
DPRINTF("internal error, index points to a %02X page!?",
mp->mp_flags);
return MDB_CORRUPTED;
}
DPRINTF("found leaf page %zu for key [%s]", mp->mp_pgno,
key ? DKEY(key) : NULL);
return MDB_SUCCESS;
}
/** Search for the page a given key should be in.
* Pushes parent pages on the cursor stack. This function just sets up
* the search; it finds the root page for \b mc's database and sets this
* as the root of the cursor's stack. Then #mdb_page_search_root() is
* called to complete the search.
* @param[in,out] mc the cursor for this operation.
* @param[in] key the key to search for. If NULL, search for the lowest
* page. (This is used by #mdb_cursor_first().)
* @param[in] modify If true, visited pages are updated with new page numbers.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
{
int rc;
pgno_t root;
/* Make sure the txn is still viable, then find the root from
* the txn's db table.
*/
if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_ERROR)) {
DPUTS("transaction has failed, must abort");
return EINVAL;
} else {
/* Make sure we're using an up-to-date root */
if (mc->mc_dbi > MAIN_DBI) {
if ((*mc->mc_dbflag & DB_STALE) ||
((flags & MDB_PS_MODIFY) && !(*mc->mc_dbflag & DB_DIRTY))) {
MDB_cursor mc2;
unsigned char dbflag = 0;
mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, flags & MDB_PS_MODIFY);
if (rc)
return rc;
if (*mc->mc_dbflag & DB_STALE) {
MDB_val data;
int exact = 0;
MDB_node *leaf = mdb_node_search(&mc2,
&mc->mc_dbx->md_name, &exact);
if (!exact)
return MDB_NOTFOUND;
mdb_node_read(mc->mc_txn, leaf, &data);
memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db));
}
if (flags & MDB_PS_MODIFY)
dbflag = DB_DIRTY;
*mc->mc_dbflag = dbflag;
}
}
root = mc->mc_db->md_root;
if (root == P_INVALID) { /* Tree is empty. */
DPUTS("tree is empty");
return MDB_NOTFOUND;
}
}
assert(root > 1);
if (!mc->mc_pg[0] || mc->mc_pg[0]->mp_pgno != root)
if ((rc = mdb_page_get(mc->mc_txn, root, &mc->mc_pg[0])))
return rc;
mc->mc_snum = 1;
mc->mc_top = 0;
DPRINTF("db %u root page %zu has flags 0x%X",
mc->mc_dbi, root, mc->mc_pg[0]->mp_flags);
if (flags & MDB_PS_MODIFY) {
if ((rc = mdb_page_touch(mc)))
return rc;
}
if (flags & MDB_PS_ROOTONLY)
return MDB_SUCCESS;
return mdb_page_search_root(mc, key, flags);
}
/** Return the data associated with a given node.
* @param[in] txn The transaction for this operation.
* @param[in] leaf The node being read.
* @param[out] data Updated to point to the node's data.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_node_read(MDB_txn *txn, MDB_node *leaf, MDB_val *data)
{
MDB_page *omp; /* overflow page */
pgno_t pgno;
int rc;
if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {
data->mv_size = NODEDSZ(leaf);
data->mv_data = NODEDATA(leaf);
return MDB_SUCCESS;
}
/* Read overflow data.
*/
data->mv_size = NODEDSZ(leaf);
memcpy(&pgno, NODEDATA(leaf), sizeof(pgno));
if ((rc = mdb_page_get(txn, pgno, &omp))) {
DPRINTF("read overflow page %zu failed", pgno);
return rc;
}
data->mv_data = METADATA(omp);
return MDB_SUCCESS;
}
int
mdb_get(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data)
{
MDB_cursor mc;
MDB_xcursor mx;
int exact = 0;
DKBUF;
assert(key);
assert(data);
DPRINTF("===> get db %u key [%s]", dbi, DKEY(key));
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
mdb_cursor_init(&mc, txn, dbi, &mx);
return mdb_cursor_set(&mc, key, data, MDB_SET, &exact);
}
/** Find a sibling for a page.
* Replaces the page at the top of the cursor's stack with the
* specified sibling, if one exists.
* @param[in] mc The cursor for this operation.
* @param[in] move_right Non-zero if the right sibling is requested,
* otherwise the left sibling.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_cursor_sibling(MDB_cursor *mc, int move_right)
{
int rc;
MDB_node *indx;
MDB_page *mp;
if (mc->mc_snum < 2) {
return MDB_NOTFOUND; /* root has no siblings */
}
mdb_cursor_pop(mc);
DPRINTF("parent page is page %zu, index %u",
mc->mc_pg[mc->mc_top]->mp_pgno, mc->mc_ki[mc->mc_top]);
if (move_right ? (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mc->mc_pg[mc->mc_top]))
: (mc->mc_ki[mc->mc_top] == 0)) {
DPRINTF("no more keys left, moving to %s sibling",
move_right ? "right" : "left");
if ((rc = mdb_cursor_sibling(mc, move_right)) != MDB_SUCCESS)
return rc;
} else {
if (move_right)
mc->mc_ki[mc->mc_top]++;
else
mc->mc_ki[mc->mc_top]--;
DPRINTF("just moving to %s index key %u",
move_right ? "right" : "left", mc->mc_ki[mc->mc_top]);
}
assert(IS_BRANCH(mc->mc_pg[mc->mc_top]));
indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(indx), &mp)))
return rc;;
mdb_cursor_push(mc, mp);
return MDB_SUCCESS;
}
/** Move the cursor to the next data item. */
static int
mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
{
MDB_page *mp;
MDB_node *leaf;
int rc;
if (mc->mc_flags & C_EOF) {
return MDB_NOTFOUND;
}
assert(mc->mc_flags & C_INITIALIZED);
mp = mc->mc_pg[mc->mc_top];
if (mc->mc_db->md_flags & MDB_DUPSORT) {
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (op == MDB_NEXT || op == MDB_NEXT_DUP) {
rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
if (op != MDB_NEXT || rc == MDB_SUCCESS)
return rc;
}
} else {
mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
if (op == MDB_NEXT_DUP)
return MDB_NOTFOUND;
}
}
DPRINTF("cursor_next: top page is %zu in cursor %p", mp->mp_pgno, (void *) mc);
if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
DPUTS("=====> move to next sibling page");
if (mdb_cursor_sibling(mc, 1) != MDB_SUCCESS) {
mc->mc_flags |= C_EOF;
mc->mc_flags &= ~C_INITIALIZED;
return MDB_NOTFOUND;
}
mp = mc->mc_pg[mc->mc_top];
DPRINTF("next page is %zu, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]);
} else
mc->mc_ki[mc->mc_top]++;
DPRINTF("==> cursor points to page %zu with %u keys, key index %u",
mp->mp_pgno, NUMKEYS(mp), mc->mc_ki[mc->mc_top]);
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
assert(IS_LEAF(mp));
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
}
if (data) {
if ((rc = mdb_node_read(mc->mc_txn, leaf, data) != MDB_SUCCESS))
return rc;
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
}
/** Move the cursor to the previous data item. */
static int
mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
{
MDB_page *mp;
MDB_node *leaf;
int rc;
assert(mc->mc_flags & C_INITIALIZED);
mp = mc->mc_pg[mc->mc_top];
if (mc->mc_db->md_flags & MDB_DUPSORT) {
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (op == MDB_PREV || op == MDB_PREV_DUP) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
if (op != MDB_PREV || rc == MDB_SUCCESS)
return rc;
} else {
mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
if (op == MDB_PREV_DUP)
return MDB_NOTFOUND;
}
}
}
DPRINTF("cursor_prev: top page is %zu in cursor %p", mp->mp_pgno, (void *) mc);
if (mc->mc_ki[mc->mc_top] == 0) {
DPUTS("=====> move to prev sibling page");
if (mdb_cursor_sibling(mc, 0) != MDB_SUCCESS) {
mc->mc_flags &= ~C_INITIALIZED;
return MDB_NOTFOUND;
}
mp = mc->mc_pg[mc->mc_top];
mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
DPRINTF("prev page is %zu, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]);
} else
mc->mc_ki[mc->mc_top]--;
mc->mc_flags &= ~C_EOF;
DPRINTF("==> cursor points to page %zu with %u keys, key index %u",
mp->mp_pgno, NUMKEYS(mp), mc->mc_ki[mc->mc_top]);
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
assert(IS_LEAF(mp));
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
}
if (data) {
if ((rc = mdb_node_read(mc->mc_txn, leaf, data) != MDB_SUCCESS))
return rc;
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
}
/** Set the cursor on a specific data item. */
static int
mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
MDB_cursor_op op, int *exactp)
{
int rc;
MDB_page *mp;
MDB_node *leaf = NULL;
DKBUF;
assert(mc);
assert(key);
assert(key->mv_size > 0);
/* See if we're already on the right page */
if (mc->mc_flags & C_INITIALIZED) {
MDB_val nodekey;
mp = mc->mc_pg[mc->mc_top];
if (!NUMKEYS(mp)) {
mc->mc_ki[mc->mc_top] = 0;
return MDB_NOTFOUND;
}
if (mp->mp_flags & P_LEAF2) {
nodekey.mv_size = mc->mc_db->md_pad;
nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
} else {
leaf = NODEPTR(mp, 0);
MDB_GET_KEY(leaf, &nodekey);
}
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
/* Probably happens rarely, but first node on the page
* was the one we wanted.
*/
mc->mc_ki[mc->mc_top] = 0;
if (exactp)
*exactp = 1;
goto set1;
}
if (rc > 0) {
unsigned int i;
unsigned int nkeys = NUMKEYS(mp);
if (nkeys > 1) {
if (mp->mp_flags & P_LEAF2) {
nodekey.mv_data = LEAF2KEY(mp,
nkeys-1, nodekey.mv_size);
} else {
leaf = NODEPTR(mp, nkeys-1);
MDB_GET_KEY(leaf, &nodekey);
}
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
/* last node was the one we wanted */
mc->mc_ki[mc->mc_top] = nkeys-1;
if (exactp)
*exactp = 1;
goto set1;
}
if (rc < 0) {
if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
/* This is definitely the right page, skip search_page */
if (mp->mp_flags & P_LEAF2) {
nodekey.mv_data = LEAF2KEY(mp,
mc->mc_ki[mc->mc_top], nodekey.mv_size);
} else {
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
MDB_GET_KEY(leaf, &nodekey);
}
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
/* current node was the one we wanted */
if (exactp)
*exactp = 1;
goto set1;
}
}
rc = 0;
goto set2;
}
}
/* If any parents have right-sibs, search.
* Otherwise, there's nothing further.
*/
for (i=0; i<mc->mc_top; i++)
if (mc->mc_ki[i] <
NUMKEYS(mc->mc_pg[i])-1)
break;
if (i == mc->mc_top) {
/* There are no other pages */
mc->mc_ki[mc->mc_top] = nkeys;
return MDB_NOTFOUND;
}
}
if (!mc->mc_top) {
/* There are no other pages */
mc->mc_ki[mc->mc_top] = 0;
return MDB_NOTFOUND;
}
}
rc = mdb_page_search(mc, key, 0);
if (rc != MDB_SUCCESS)
return rc;
mp = mc->mc_pg[mc->mc_top];
assert(IS_LEAF(mp));
set2:
leaf = mdb_node_search(mc, key, exactp);
if (exactp != NULL && !*exactp) {
/* MDB_SET specified and not an exact match. */
return MDB_NOTFOUND;
}
if (leaf == NULL) {
DPUTS("===> inexact leaf not found, goto sibling");
if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS)
return rc; /* no entries matched */
mp = mc->mc_pg[mc->mc_top];
assert(IS_LEAF(mp));
leaf = NODEPTR(mp, 0);
}
set1:
mc->mc_flags |= C_INITIALIZED;
mc->mc_flags &= ~C_EOF;
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
}
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (op == MDB_SET || op == MDB_SET_KEY || op == MDB_SET_RANGE) {
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
} else {
int ex2, *ex2p;
if (op == MDB_GET_BOTH) {
ex2p = &ex2;
ex2 = 0;
} else {
ex2p = NULL;
}
rc = mdb_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_SET_RANGE, ex2p);
if (rc != MDB_SUCCESS)
return rc;
}
} else if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {
MDB_val d2;
if ((rc = mdb_node_read(mc->mc_txn, leaf, &d2)) != MDB_SUCCESS)
return rc;
rc = mc->mc_dbx->md_dcmp(data, &d2);
if (rc) {
if (op == MDB_GET_BOTH || rc > 0)
return MDB_NOTFOUND;
}
} else {
if (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
/* The key already matches in all other cases */
if (op == MDB_SET_RANGE || op == MDB_SET_KEY)
MDB_GET_KEY(leaf, key);
DPRINTF("==> cursor placed on key [%s]", DKEY(key));
return rc;
}
/** Move the cursor to the first item in the database. */
static int
mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data)
{
int rc;
MDB_node *leaf;
if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
rc = mdb_page_search(mc, NULL, 0);
if (rc != MDB_SUCCESS)
return rc;
}
assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
mc->mc_flags |= C_INITIALIZED;
mc->mc_flags &= ~C_EOF;
mc->mc_ki[mc->mc_top] = 0;
if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, key->mv_size);
return MDB_SUCCESS;
}
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc)
return rc;
} else {
if (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
}
/** Move the cursor to the last item in the database. */
static int
mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)
{
int rc;
MDB_node *leaf;
if (!(mc->mc_flags & C_EOF)) {
if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
MDB_val lkey;
lkey.mv_size = MAXKEYSIZE+1;
lkey.mv_data = NULL;
rc = mdb_page_search(mc, &lkey, 0);
if (rc != MDB_SUCCESS)
return rc;
}
assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
mc->mc_flags |= C_INITIALIZED|C_EOF;
}
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc)
return rc;
} else {
if (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
}
int
mdb_cursor_get(MDB_cursor *mc, MDB_val *key, MDB_val *data,
MDB_cursor_op op)
{
int rc;
int exact = 0;
assert(mc);
switch (op) {
case MDB_GET_CURRENT:
if (!mc->mc_flags & C_INITIALIZED) {
rc = EINVAL;
} else {
MDB_page *mp = mc->mc_pg[mc->mc_top];
if (!NUMKEYS(mp)) {
mc->mc_ki[mc->mc_top] = 0;
rc = MDB_NOTFOUND;
break;
}
rc = MDB_SUCCESS;
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
} else {
MDB_node *leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
MDB_GET_KEY(leaf, key);
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_get(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_GET_CURRENT);
} else {
rc = mdb_node_read(mc->mc_txn, leaf, data);
}
}
}
}
break;
case MDB_GET_BOTH:
case MDB_GET_BOTH_RANGE:
if (data == NULL || mc->mc_xcursor == NULL) {
rc = EINVAL;
break;
}
/* FALLTHRU */
case MDB_SET:
case MDB_SET_KEY:
case MDB_SET_RANGE:
if (key == NULL || key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
rc = EINVAL;
} else if (op == MDB_SET_RANGE)
rc = mdb_cursor_set(mc, key, data, op, NULL);
else
rc = mdb_cursor_set(mc, key, data, op, &exact);
break;
case MDB_GET_MULTIPLE:
if (data == NULL ||
!(mc->mc_db->md_flags & MDB_DUPFIXED) ||
!(mc->mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
rc = MDB_SUCCESS;
if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) ||
(mc->mc_xcursor->mx_cursor.mc_flags & C_EOF))
break;
goto fetchm;
case MDB_NEXT_MULTIPLE:
if (data == NULL ||
!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
rc = EINVAL;
break;
}
if (!(mc->mc_flags & C_INITIALIZED))
rc = mdb_cursor_first(mc, key, data);
else
rc = mdb_cursor_next(mc, key, data, MDB_NEXT_DUP);
if (rc == MDB_SUCCESS) {
if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
MDB_cursor *mx;
fetchm:
mx = &mc->mc_xcursor->mx_cursor;
data->mv_size = NUMKEYS(mx->mc_pg[mx->mc_top]) *
mx->mc_db->md_pad;
data->mv_data = METADATA(mx->mc_pg[mx->mc_top]);
mx->mc_ki[mx->mc_top] = NUMKEYS(mx->mc_pg[mx->mc_top])-1;
} else {
rc = MDB_NOTFOUND;
}
}
break;
case MDB_NEXT:
case MDB_NEXT_DUP:
case MDB_NEXT_NODUP:
if (!(mc->mc_flags & C_INITIALIZED))
rc = mdb_cursor_first(mc, key, data);
else
rc = mdb_cursor_next(mc, key, data, op);
break;
case MDB_PREV:
case MDB_PREV_DUP:
case MDB_PREV_NODUP:
if (!(mc->mc_flags & C_INITIALIZED) || (mc->mc_flags & C_EOF)) {
rc = mdb_cursor_last(mc, key, data);
mc->mc_flags &= ~C_EOF;
} else
rc = mdb_cursor_prev(mc, key, data, op);
break;
case MDB_FIRST:
rc = mdb_cursor_first(mc, key, data);
break;
case MDB_FIRST_DUP:
if (data == NULL ||
!(mc->mc_db->md_flags & MDB_DUPSORT) ||
!(mc->mc_flags & C_INITIALIZED) ||
!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
break;
case MDB_LAST:
rc = mdb_cursor_last(mc, key, data);
break;
case MDB_LAST_DUP:
if (data == NULL ||
!(mc->mc_db->md_flags & MDB_DUPSORT) ||
!(mc->mc_flags & C_INITIALIZED) ||
!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
break;
default:
DPRINTF("unhandled/unimplemented cursor operation %u", op);
rc = EINVAL;
break;
}
return rc;
}
/** Touch all the pages in the cursor stack.
* Makes sure all the pages are writable, before attempting a write operation.
* @param[in] mc The cursor to operate on.
*/
static int
mdb_cursor_touch(MDB_cursor *mc)
{
int rc;
if (mc->mc_dbi > MAIN_DBI && !(*mc->mc_dbflag & DB_DIRTY)) {
MDB_cursor mc2;
mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, MDB_PS_MODIFY);
if (rc)
return rc;
*mc->mc_dbflag = DB_DIRTY;
}
for (mc->mc_top = 0; mc->mc_top < mc->mc_snum; mc->mc_top++) {
rc = mdb_page_touch(mc);
if (rc)
return rc;
}
mc->mc_top = mc->mc_snum-1;
return MDB_SUCCESS;
}
int
mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
unsigned int flags)
{
MDB_node *leaf = NULL;
MDB_val xdata, *rdata, dkey;
MDB_page *fp;
MDB_db dummy;
int do_sub = 0, insert = 0;
unsigned int mcount = 0;
size_t nsize;
int rc, rc2;
MDB_pagebuf pbuf;
char dbuf[MAXKEYSIZE+1];
unsigned int nflags;
DKBUF;
if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_RDONLY))
return EACCES;
DPRINTF("==> put db %u key [%s], size %zu, data size %zu",
mc->mc_dbi, DKEY(key), key ? key->mv_size:0, data->mv_size);
dkey.mv_size = 0;
if (flags == MDB_CURRENT) {
if (!(mc->mc_flags & C_INITIALIZED))
return EINVAL;
rc = MDB_SUCCESS;
} else if (mc->mc_db->md_root == P_INVALID) {
MDB_page *np;
/* new database, write a root leaf page */
DPUTS("allocating new root leaf page");
if ((rc = mdb_page_new(mc, P_LEAF, 1, &np))) {
return rc;
}
mc->mc_snum = 0;
mdb_cursor_push(mc, np);
mc->mc_db->md_root = np->mp_pgno;
mc->mc_db->md_depth++;
*mc->mc_dbflag = DB_DIRTY;
if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
== MDB_DUPFIXED)
np->mp_flags |= P_LEAF2;
mc->mc_flags |= C_INITIALIZED;
rc = MDB_NOTFOUND;
goto top;
} else {
int exact = 0;
MDB_val d2;
if (flags & MDB_APPEND) {
MDB_val k2;
rc = mdb_cursor_last(mc, &k2, &d2);
if (rc == 0) {
rc = mc->mc_dbx->md_cmp(key, &k2);
if (rc > 0) {
rc = MDB_NOTFOUND;
mc->mc_ki[mc->mc_top]++;
} else {
rc = 0;
}
}
} else {
rc = mdb_cursor_set(mc, key, &d2, MDB_SET, &exact);
}
if ((flags & MDB_NOOVERWRITE) && rc == 0) {
DPRINTF("duplicate key [%s]", DKEY(key));
*data = d2;
return MDB_KEYEXIST;
}
if (rc && rc != MDB_NOTFOUND)
return rc;
}
/* Cursor is positioned, now make sure all pages are writable */
rc2 = mdb_cursor_touch(mc);
if (rc2)
return rc2;
top:
/* The key already exists */
if (rc == MDB_SUCCESS) {
/* there's only a key anyway, so this is a no-op */
if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
unsigned int ksize = mc->mc_db->md_pad;
if (key->mv_size != ksize)
return EINVAL;
if (flags == MDB_CURRENT) {
char *ptr = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], ksize);
memcpy(ptr, key->mv_data, ksize);
}
return MDB_SUCCESS;
}
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
/* DB has dups? */
if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT)) {
/* Was a single item before, must convert now */
more:
if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
/* Just overwrite the current item */
if (flags == MDB_CURRENT)
goto current;
dkey.mv_size = NODEDSZ(leaf);
dkey.mv_data = NODEDATA(leaf);
#if UINT_MAX < SIZE_MAX
if (mc->mc_dbx->md_dcmp == mdb_cmp_int && dkey.mv_size == sizeof(size_t))
#ifdef MISALIGNED_OK
mc->mc_dbx->md_dcmp = mdb_cmp_long;
#else
mc->mc_dbx->md_dcmp = mdb_cmp_cint;
#endif
#endif
/* if data matches, ignore it */
if (!mc->mc_dbx->md_dcmp(data, &dkey))
return (flags == MDB_NODUPDATA) ? MDB_KEYEXIST : MDB_SUCCESS;
/* create a fake page for the dup items */
memcpy(dbuf, dkey.mv_data, dkey.mv_size);
dkey.mv_data = dbuf;
fp = (MDB_page *)&pbuf;
fp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
fp->mp_flags = P_LEAF|P_DIRTY|P_SUBP;
fp->mp_lower = PAGEHDRSZ;
fp->mp_upper = PAGEHDRSZ + dkey.mv_size + data->mv_size;
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
fp->mp_flags |= P_LEAF2;
fp->mp_pad = data->mv_size;
fp->mp_upper += 2 * data->mv_size; /* leave space for 2 more */
} else {
fp->mp_upper += 2 * sizeof(indx_t) + 2 * NODESIZE +
(dkey.mv_size & 1) + (data->mv_size & 1);
}
mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
do_sub = 1;
rdata = &xdata;
xdata.mv_size = fp->mp_upper;
xdata.mv_data = fp;
flags |= F_DUPDATA;
goto new_sub;
}
if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
/* See if we need to convert from fake page to subDB */
MDB_page *mp;
unsigned int offset;
unsigned int i;
fp = NODEDATA(leaf);
if (flags == MDB_CURRENT) {
reuse:
fp->mp_flags |= P_DIRTY;
COPY_PGNO(fp->mp_pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
mc->mc_xcursor->mx_cursor.mc_pg[0] = fp;
flags |= F_DUPDATA;
goto put_sub;
}
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
offset = fp->mp_pad;
if (SIZELEFT(fp) >= offset)
goto reuse;
offset *= 4; /* space for 4 more */
} else {
offset = NODESIZE + sizeof(indx_t) + data->mv_size;
}
offset += offset & 1;
if (NODESIZE + sizeof(indx_t) + NODEKSZ(leaf) + NODEDSZ(leaf) +
offset >= (mc->mc_txn->mt_env->me_psize - PAGEHDRSZ) /
MDB_MINKEYS) {
/* yes, convert it */
dummy.md_flags = 0;
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
dummy.md_pad = fp->mp_pad;
dummy.md_flags = MDB_DUPFIXED;
if (mc->mc_db->md_flags & MDB_INTEGERDUP)
dummy.md_flags |= MDB_INTEGERKEY;
}
dummy.md_depth = 1;
dummy.md_branch_pages = 0;
dummy.md_leaf_pages = 1;
dummy.md_overflow_pages = 0;
dummy.md_entries = NUMKEYS(fp);
rdata = &xdata;
xdata.mv_size = sizeof(MDB_db);
xdata.mv_data = &dummy;
if ((rc = mdb_page_alloc(mc, 1, &mp)))
return rc;
offset = mc->mc_txn->mt_env->me_psize - NODEDSZ(leaf);
flags |= F_DUPDATA|F_SUBDATA;
dummy.md_root = mp->mp_pgno;
} else {
/* no, just grow it */
rdata = &xdata;
xdata.mv_size = NODEDSZ(leaf) + offset;
xdata.mv_data = &pbuf;
mp = (MDB_page *)&pbuf;
mp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
flags |= F_DUPDATA;
}
mp->mp_flags = fp->mp_flags | P_DIRTY;
mp->mp_pad = fp->mp_pad;
mp->mp_lower = fp->mp_lower;
mp->mp_upper = fp->mp_upper + offset;
if (IS_LEAF2(fp)) {
memcpy(METADATA(mp), METADATA(fp), NUMKEYS(fp) * fp->mp_pad);
} else {
nsize = NODEDSZ(leaf) - fp->mp_upper;
memcpy((char *)mp + mp->mp_upper, (char *)fp + fp->mp_upper, nsize);
for (i=0; i<NUMKEYS(fp); i++)
mp->mp_ptrs[i] = fp->mp_ptrs[i] + offset;
}
mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
do_sub = 1;
goto new_sub;
}
/* data is on sub-DB, just store it */
flags |= F_DUPDATA|F_SUBDATA;
goto put_sub;
}
current:
/* overflow page overwrites need special handling */
if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
MDB_page *omp;
pgno_t pg;
int ovpages, dpages;
ovpages = OVPAGES(NODEDSZ(leaf), mc->mc_txn->mt_env->me_psize);
dpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
memcpy(&pg, NODEDATA(leaf), sizeof(pg));
mdb_page_get(mc->mc_txn, pg, &omp);
/* Is the ov page writable and large enough? */
if ((omp->mp_flags & P_DIRTY) && ovpages >= dpages) {
/* yes, overwrite it. Note in this case we don't
* bother to try shrinking the node if the new data
* is smaller than the overflow threshold.
*/
if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = METADATA(omp);
else
memcpy(METADATA(omp), data->mv_data, data->mv_size);
goto done;
} else {
/* no, free ovpages */
int i;
mc->mc_db->md_overflow_pages -= ovpages;
for (i=0; i<ovpages; i++) {
DPRINTF("freed ov page %zu", pg);
mdb_midl_append(&mc->mc_txn->mt_free_pgs, pg);
pg++;
}
}
} else if (NODEDSZ(leaf) == data->mv_size) {
/* same size, just replace it. Note that we could
* also reuse this node if the new data is smaller,
* but instead we opt to shrink the node in that case.
*/
if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = NODEDATA(leaf);
else
memcpy(NODEDATA(leaf), data->mv_data, data->mv_size);
goto done;
}
mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
mc->mc_db->md_entries--;
} else {
DPRINTF("inserting key at index %i", mc->mc_ki[mc->mc_top]);
insert = 1;
}
rdata = data;
new_sub:
nflags = flags & NODE_ADD_FLAGS;
nsize = IS_LEAF2(mc->mc_pg[mc->mc_top]) ? key->mv_size : mdb_leaf_size(mc->mc_txn->mt_env, key, rdata);
if (SIZELEFT(mc->mc_pg[mc->mc_top]) < nsize) {
if (( flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA )
nflags &= ~MDB_APPEND;
if (!insert)
nflags |= MDB_SPLIT_REPLACE;
rc = mdb_page_split(mc, key, rdata, P_INVALID, nflags);
} else {
/* There is room already in this leaf page. */
rc = mdb_node_add(mc, mc->mc_ki[mc->mc_top], key, rdata, 0, nflags);
if (rc == 0 && !do_sub && insert) {
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
unsigned i = mc->mc_top;
MDB_page *mp = mc->mc_pg[i];
if (mc->mc_flags & C_SUB)
dbi--;
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == mc || m3->mc_snum < mc->mc_snum) continue;
if (m3->mc_pg[i] == mp && m3->mc_ki[i] >= mc->mc_ki[i]) {
m3->mc_ki[i]++;
}
}
}
}
if (rc != MDB_SUCCESS)
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
else {
/* Now store the actual data in the child DB. Note that we're
* storing the user data in the keys field, so there are strict
* size limits on dupdata. The actual data fields of the child
* DB are all zero size.
*/
if (do_sub) {
int xflags;
put_sub:
xdata.mv_size = 0;
xdata.mv_data = "";
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (flags & MDB_CURRENT) {
xflags = MDB_CURRENT;
} else {
mdb_xcursor_init1(mc, leaf);
xflags = (flags & MDB_NODUPDATA) ? MDB_NOOVERWRITE : 0;
}
/* converted, write the original data first */
if (dkey.mv_size) {
rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, &dkey, &xdata, xflags);
if (rc)
return rc;
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2;
unsigned i = mc->mc_top;
MDB_page *mp = mc->mc_pg[i];
for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
if (m2->mc_pg[i] == mp && m2->mc_ki[i] == mc->mc_ki[i]) {
mdb_xcursor_init1(m2, leaf);
}
}
}
}
if (flags & MDB_APPENDDUP)
xflags |= MDB_APPEND;
rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, data, &xdata, xflags);
if (flags & F_SUBDATA) {
void *db = NODEDATA(leaf);
memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
}
}
/* sub-writes might have failed so check rc again.
* Don't increment count if we just replaced an existing item.
*/
if (!rc && !(flags & MDB_CURRENT))
mc->mc_db->md_entries++;
if (flags & MDB_MULTIPLE) {
mcount++;
if (mcount < data[1].mv_size) {
data[0].mv_data = (char *)data[0].mv_data + data[0].mv_size;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
goto more;
}
}
}
done:
return rc;
}
int
mdb_cursor_del(MDB_cursor *mc, unsigned int flags)
{
MDB_node *leaf;
int rc;
if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_RDONLY))
return EACCES;
if (!mc->mc_flags & C_INITIALIZED)
return EINVAL;
rc = mdb_cursor_touch(mc);
if (rc)
return rc;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (!IS_LEAF2(mc->mc_pg[mc->mc_top]) && F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (flags != MDB_NODUPDATA) {
if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
}
rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, 0);
/* If sub-DB still has entries, we're done */
if (mc->mc_xcursor->mx_db.md_entries) {
if (leaf->mn_flags & F_SUBDATA) {
/* update subDB info */
void *db = NODEDATA(leaf);
memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
} else {
/* shrink fake page */
mdb_node_shrink(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
}
mc->mc_db->md_entries--;
return rc;
}
/* otherwise fall thru and delete the sub-DB */
}
if (leaf->mn_flags & F_SUBDATA) {
/* add all the child DB's pages to the free list */
rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
if (rc == MDB_SUCCESS) {
mc->mc_db->md_entries -=
mc->mc_xcursor->mx_db.md_entries;
}
}
}
return mdb_cursor_del0(mc, leaf);
}
/** Allocate and initialize new pages for a database.
* @param[in] mc a cursor on the database being added to.
* @param[in] flags flags defining what type of page is being allocated.
* @param[in] num the number of pages to allocate. This is usually 1,
* unless allocating overflow pages for a large record.
* @param[out] mp Address of a page, or NULL on failure.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp)
{
MDB_page *np;
int rc;
if ((rc = mdb_page_alloc(mc, num, &np)))
return rc;
DPRINTF("allocated new mpage %zu, page size %u",
np->mp_pgno, mc->mc_txn->mt_env->me_psize);
np->mp_flags = flags | P_DIRTY;
np->mp_lower = PAGEHDRSZ;
np->mp_upper = mc->mc_txn->mt_env->me_psize;
if (IS_BRANCH(np))
mc->mc_db->md_branch_pages++;
else if (IS_LEAF(np))
mc->mc_db->md_leaf_pages++;
else if (IS_OVERFLOW(np)) {
mc->mc_db->md_overflow_pages += num;
np->mp_pages = num;
}
*mp = np;
return 0;
}
/** Calculate the size of a leaf node.
* The size depends on the environment's page size; if a data item
* is too large it will be put onto an overflow page and the node
* size will only include the key and not the data. Sizes are always
* rounded up to an even number of bytes, to guarantee 2-byte alignment
* of the #MDB_node headers.
* @param[in] env The environment handle.
* @param[in] key The key for the node.
* @param[in] data The data for the node.
* @return The number of bytes needed to store the node.
*/
static size_t
mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
{
size_t sz;
sz = LEAFSIZE(key, data);
if (sz >= env->me_psize / MDB_MINKEYS) {
/* put on overflow page */
sz -= data->mv_size - sizeof(pgno_t);
}
sz += sz & 1;
return sz + sizeof(indx_t);
}
/** Calculate the size of a branch node.
* The size should depend on the environment's page size but since
* we currently don't support spilling large keys onto overflow
* pages, it's simply the size of the #MDB_node header plus the
* size of the key. Sizes are always rounded up to an even number
* of bytes, to guarantee 2-byte alignment of the #MDB_node headers.
* @param[in] env The environment handle.
* @param[in] key The key for the node.
* @return The number of bytes needed to store the node.
*/
static size_t
mdb_branch_size(MDB_env *env, MDB_val *key)
{
size_t sz;
sz = INDXSIZE(key);
if (sz >= env->me_psize / MDB_MINKEYS) {
/* put on overflow page */
/* not implemented */
/* sz -= key->size - sizeof(pgno_t); */
}
return sz + sizeof(indx_t);
}
/** Add a node to the page pointed to by the cursor.
* @param[in] mc The cursor for this operation.
* @param[in] indx The index on the page where the new node should be added.
* @param[in] key The key for the new node.
* @param[in] data The data for the new node, if any.
* @param[in] pgno The page number, if adding a branch node.
* @param[in] flags Flags for the node.
* @return 0 on success, non-zero on failure. Possible errors are:
* <ul>
* <li>ENOMEM - failed to allocate overflow pages for the node.
* <li>MDB_PAGE_FULL - there is insufficient room in the page. This error
* should never happen since all callers already calculate the
* page's free space before calling this function.
* </ul>
*/
static int
mdb_node_add(MDB_cursor *mc, indx_t indx,
MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags)
{
unsigned int i;
size_t node_size = NODESIZE;
indx_t ofs;
MDB_node *node;
MDB_page *mp = mc->mc_pg[mc->mc_top];
MDB_page *ofp = NULL; /* overflow page */
DKBUF;
assert(mp->mp_upper >= mp->mp_lower);
DPRINTF("add to %s %spage %zu index %i, data size %zu key size %zu [%s]",
IS_LEAF(mp) ? "leaf" : "branch",
IS_SUBP(mp) ? "sub-" : "",
mp->mp_pgno, indx, data ? data->mv_size : 0,
key ? key->mv_size : 0, key ? DKEY(key) : NULL);
if (IS_LEAF2(mp)) {
/* Move higher keys up one slot. */
int ksize = mc->mc_db->md_pad, dif;
char *ptr = LEAF2KEY(mp, indx, ksize);
dif = NUMKEYS(mp) - indx;
if (dif > 0)
memmove(ptr+ksize, ptr, dif*ksize);
/* insert new key */
memcpy(ptr, key->mv_data, ksize);
/* Just using these for counting */
mp->mp_lower += sizeof(indx_t);
mp->mp_upper -= ksize - sizeof(indx_t);
return MDB_SUCCESS;
}
if (key != NULL)
node_size += key->mv_size;
if (IS_LEAF(mp)) {
assert(data);
if (F_ISSET(flags, F_BIGDATA)) {
/* Data already on overflow page. */
node_size += sizeof(pgno_t);
} else if (node_size + data->mv_size >= mc->mc_txn->mt_env->me_psize / MDB_MINKEYS) {
int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
int rc;
/* Put data on overflow page. */
DPRINTF("data size is %zu, node would be %zu, put data on overflow page",
data->mv_size, node_size+data->mv_size);
node_size += sizeof(pgno_t);
if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
return rc;
DPRINTF("allocated overflow page %zu", ofp->mp_pgno);
flags |= F_BIGDATA;
} else {
node_size += data->mv_size;
}
}
node_size += node_size & 1;
if (node_size + sizeof(indx_t) > SIZELEFT(mp)) {
DPRINTF("not enough room in page %zu, got %u ptrs",
mp->mp_pgno, NUMKEYS(mp));
DPRINTF("upper - lower = %u - %u = %u", mp->mp_upper, mp->mp_lower,
mp->mp_upper - mp->mp_lower);
DPRINTF("node size = %zu", node_size);
return MDB_PAGE_FULL;
}
/* Move higher pointers up one slot. */
for (i = NUMKEYS(mp); i > indx; i--)
mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
/* Adjust free space offsets. */
ofs = mp->mp_upper - node_size;
assert(ofs >= mp->mp_lower + sizeof(indx_t));
mp->mp_ptrs[indx] = ofs;
mp->mp_upper = ofs;
mp->mp_lower += sizeof(indx_t);
/* Write the node data. */
node = NODEPTR(mp, indx);
node->mn_ksize = (key == NULL) ? 0 : key->mv_size;
node->mn_flags = flags;
if (IS_LEAF(mp))
SETDSZ(node,data->mv_size);
else
SETPGNO(node,pgno);
if (key)
memcpy(NODEKEY(node), key->mv_data, key->mv_size);
if (IS_LEAF(mp)) {
assert(key);
if (ofp == NULL) {
if (F_ISSET(flags, F_BIGDATA))
memcpy(node->mn_data + key->mv_size, data->mv_data,
sizeof(pgno_t));
else if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = node->mn_data + key->mv_size;
else
memcpy(node->mn_data + key->mv_size, data->mv_data,
data->mv_size);
} else {
memcpy(node->mn_data + key->mv_size, &ofp->mp_pgno,
sizeof(pgno_t));
if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = METADATA(ofp);
else
memcpy(METADATA(ofp), data->mv_data, data->mv_size);
}
}
return MDB_SUCCESS;
}
/** Delete the specified node from a page.
* @param[in] mp The page to operate on.
* @param[in] indx The index of the node to delete.
* @param[in] ksize The size of a node. Only used if the page is
* part of a #MDB_DUPFIXED database.
*/
static void
mdb_node_del(MDB_page *mp, indx_t indx, int ksize)
{
unsigned int sz;
indx_t i, j, numkeys, ptr;
MDB_node *node;
char *base;
#if MDB_DEBUG
{
pgno_t pgno;
COPY_PGNO(pgno, mp->mp_pgno);
DPRINTF("delete node %u on %s page %zu", indx,
IS_LEAF(mp) ? "leaf" : "branch", pgno);
}
#endif
assert(indx < NUMKEYS(mp));
if (IS_LEAF2(mp)) {
int x = NUMKEYS(mp) - 1 - indx;
base = LEAF2KEY(mp, indx, ksize);
if (x)
memmove(base, base + ksize, x * ksize);
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += ksize - sizeof(indx_t);
return;
}
node = NODEPTR(mp, indx);
sz = NODESIZE + node->mn_ksize;
if (IS_LEAF(mp)) {
if (F_ISSET(node->mn_flags, F_BIGDATA))
sz += sizeof(pgno_t);
else
sz += NODEDSZ(node);
}
sz += sz & 1;
ptr = mp->mp_ptrs[indx];
numkeys = NUMKEYS(mp);
for (i = j = 0; i < numkeys; i++) {
if (i != indx) {
mp->mp_ptrs[j] = mp->mp_ptrs[i];
if (mp->mp_ptrs[i] < ptr)
mp->mp_ptrs[j] += sz;
j++;
}
}
base = (char *)mp + mp->mp_upper;
memmove(base + sz, base, ptr - mp->mp_upper);
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += sz;
}
/** Compact the main page after deleting a node on a subpage.
* @param[in] mp The main page to operate on.
* @param[in] indx The index of the subpage on the main page.
*/
static void
mdb_node_shrink(MDB_page *mp, indx_t indx)
{
MDB_node *node;
MDB_page *sp, *xp;
char *base;
int osize, nsize;
int delta;
indx_t i, numkeys, ptr;
node = NODEPTR(mp, indx);
sp = (MDB_page *)NODEDATA(node);
osize = NODEDSZ(node);
delta = sp->mp_upper - sp->mp_lower;
SETDSZ(node, osize - delta);
xp = (MDB_page *)((char *)sp + delta);
/* shift subpage upward */
if (IS_LEAF2(sp)) {
nsize = NUMKEYS(sp) * sp->mp_pad;
memmove(METADATA(xp), METADATA(sp), nsize);
} else {
int i;
nsize = osize - sp->mp_upper;
numkeys = NUMKEYS(sp);
for (i=numkeys-1; i>=0; i--)
xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;
}
xp->mp_upper = sp->mp_lower;
xp->mp_lower = sp->mp_lower;
xp->mp_flags = sp->mp_flags;
xp->mp_pad = sp->mp_pad;
COPY_PGNO(xp->mp_pgno, mp->mp_pgno);
/* shift lower nodes upward */
ptr = mp->mp_ptrs[indx];
numkeys = NUMKEYS(mp);
for (i = 0; i < numkeys; i++) {
if (mp->mp_ptrs[i] <= ptr)
mp->mp_ptrs[i] += delta;
}
base = (char *)mp + mp->mp_upper;
memmove(base + delta, base, ptr - mp->mp_upper + NODESIZE + NODEKSZ(node));
mp->mp_upper += delta;
}
/** Initial setup of a sorted-dups cursor.
* Sorted duplicates are implemented as a sub-database for the given key.
* The duplicate data items are actually keys of the sub-database.
* Operations on the duplicate data items are performed using a sub-cursor
* initialized when the sub-database is first accessed. This function does
* the preliminary setup of the sub-cursor, filling in the fields that
* depend only on the parent DB.
* @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
*/
static void
mdb_xcursor_init0(MDB_cursor *mc)
{
MDB_xcursor *mx = mc->mc_xcursor;
mx->mx_cursor.mc_xcursor = NULL;
mx->mx_cursor.mc_txn = mc->mc_txn;
mx->mx_cursor.mc_db = &mx->mx_db;
mx->mx_cursor.mc_dbx = &mx->mx_dbx;
mx->mx_cursor.mc_dbi = mc->mc_dbi+1;
mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
mx->mx_cursor.mc_snum = 0;
mx->mx_cursor.mc_top = 0;
mx->mx_cursor.mc_flags = C_SUB;
mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp;
mx->mx_dbx.md_dcmp = NULL;
mx->mx_dbx.md_rel = mc->mc_dbx->md_rel;
}
/** Final setup of a sorted-dups cursor.
* Sets up the fields that depend on the data from the main cursor.
* @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
* @param[in] node The data containing the #MDB_db record for the
* sorted-dup database.
*/
static void
mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
{
MDB_xcursor *mx = mc->mc_xcursor;
if (node->mn_flags & F_SUBDATA) {
memcpy(&mx->mx_db, NODEDATA(node), sizeof(MDB_db));
mx->mx_cursor.mc_pg[0] = 0;
mx->mx_cursor.mc_snum = 0;
mx->mx_cursor.mc_flags = C_SUB;
} else {
MDB_page *fp = NODEDATA(node);
mx->mx_db.md_pad = mc->mc_pg[mc->mc_top]->mp_pad;
mx->mx_db.md_flags = 0;
mx->mx_db.md_depth = 1;
mx->mx_db.md_branch_pages = 0;
mx->mx_db.md_leaf_pages = 1;
mx->mx_db.md_overflow_pages = 0;
mx->mx_db.md_entries = NUMKEYS(fp);
COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);
mx->mx_cursor.mc_snum = 1;
mx->mx_cursor.mc_flags = C_INITIALIZED|C_SUB;
mx->mx_cursor.mc_top = 0;
mx->mx_cursor.mc_pg[0] = fp;
mx->mx_cursor.mc_ki[0] = 0;
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
mx->mx_db.md_flags = MDB_DUPFIXED;
mx->mx_db.md_pad = fp->mp_pad;
if (mc->mc_db->md_flags & MDB_INTEGERDUP)
mx->mx_db.md_flags |= MDB_INTEGERKEY;
}
}
DPRINTF("Sub-db %u for db %u root page %zu", mx->mx_cursor.mc_dbi, mc->mc_dbi,
mx->mx_db.md_root);
mx->mx_dbflag = (F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY)) ?
DB_DIRTY : 0;
mx->mx_dbx.md_name.mv_data = NODEKEY(node);
mx->mx_dbx.md_name.mv_size = node->mn_ksize;
#if UINT_MAX < SIZE_MAX
if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(size_t))
#ifdef MISALIGNED_OK
mx->mx_dbx.md_cmp = mdb_cmp_long;
#else
mx->mx_dbx.md_cmp = mdb_cmp_cint;
#endif
#endif
}
/** Initialize a cursor for a given transaction and database. */
static void
mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
{
mc->mc_orig = NULL;
mc->mc_dbi = dbi;
mc->mc_txn = txn;
mc->mc_db = &txn->mt_dbs[dbi];
mc->mc_dbx = &txn->mt_dbxs[dbi];
mc->mc_dbflag = &txn->mt_dbflags[dbi];
mc->mc_snum = 0;
mc->mc_top = 0;
mc->mc_pg[0] = 0;
mc->mc_flags = 0;
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
assert(mx != NULL);
mc->mc_xcursor = mx;
mdb_xcursor_init0(mc);
} else {
mc->mc_xcursor = NULL;
}
if (*mc->mc_dbflag & DB_STALE) {
mdb_page_search(mc, NULL, MDB_PS_ROOTONLY);
}
}
int
mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
{
MDB_cursor *mc;
MDB_xcursor *mx = NULL;
size_t size = sizeof(MDB_cursor);
if (txn == NULL || ret == NULL || dbi >= txn->mt_numdbs)
return EINVAL;
/* Allow read access to the freelist */
if (!dbi && !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
return EINVAL;
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT)
size += sizeof(MDB_xcursor);
if ((mc = malloc(size)) != NULL) {
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
mx = (MDB_xcursor *)(mc + 1);
}
mdb_cursor_init(mc, txn, dbi, mx);
if (txn->mt_cursors) {
mc->mc_next = txn->mt_cursors[dbi];
txn->mt_cursors[dbi] = mc;
}
mc->mc_flags |= C_ALLOCD;
} else {
return ENOMEM;
}
*ret = mc;
return MDB_SUCCESS;
}
int
mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)
{
if (txn == NULL || mc == NULL || mc->mc_dbi >= txn->mt_numdbs)
return EINVAL;
if (txn->mt_cursors)
return EINVAL;
mdb_cursor_init(mc, txn, mc->mc_dbi, mc->mc_xcursor);
return MDB_SUCCESS;
}
/* Return the count of duplicate data items for the current key */
int
mdb_cursor_count(MDB_cursor *mc, size_t *countp)
{
MDB_node *leaf;
if (mc == NULL || countp == NULL)
return EINVAL;
if (!(mc->mc_db->md_flags & MDB_DUPSORT))
return EINVAL;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
*countp = 1;
} else {
if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
return EINVAL;
*countp = mc->mc_xcursor->mx_db.md_entries;
}
return MDB_SUCCESS;
}
void
mdb_cursor_close(MDB_cursor *mc)
{
if (mc != NULL) {
/* remove from txn, if tracked */
if (mc->mc_txn->mt_cursors) {
MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];
while (*prev && *prev != mc) prev = &(*prev)->mc_next;
if (*prev == mc)
*prev = mc->mc_next;
}
if (mc->mc_flags & C_ALLOCD)
free(mc);
}
}
MDB_txn *
mdb_cursor_txn(MDB_cursor *mc)
{
if (!mc) return NULL;
return mc->mc_txn;
}
MDB_dbi
mdb_cursor_dbi(MDB_cursor *mc)
{
if (!mc) return 0;
return mc->mc_dbi;
}
/** Replace the key for a node with a new key.
* @param[in] mp The page containing the node to operate on.
* @param[in] indx The index of the node to operate on.
* @param[in] key The new key to use.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_update_key(MDB_page *mp, indx_t indx, MDB_val *key)
{
MDB_node *node;
char *base;
size_t len;
int delta, delta0;
indx_t ptr, i, numkeys;
DKBUF;
node = NODEPTR(mp, indx);
ptr = mp->mp_ptrs[indx];
#if MDB_DEBUG
{
MDB_val k2;
char kbuf2[(MAXKEYSIZE*2+1)];
k2.mv_data = NODEKEY(node);
k2.mv_size = node->mn_ksize;
DPRINTF("update key %u (ofs %u) [%s] to [%s] on page %zu",
indx, ptr,
mdb_dkey(&k2, kbuf2),
DKEY(key),
mp->mp_pgno);
}
#endif
delta0 = delta = key->mv_size - node->mn_ksize;
/* Must be 2-byte aligned. If new key is
* shorter by 1, the shift will be skipped.
*/
delta += (delta & 1);
if (delta) {
if (delta > 0 && SIZELEFT(mp) < delta) {
DPRINTF("OUCH! Not enough room, delta = %d", delta);
return MDB_PAGE_FULL;
}
numkeys = NUMKEYS(mp);
for (i = 0; i < numkeys; i++) {
if (mp->mp_ptrs[i] <= ptr)
mp->mp_ptrs[i] -= delta;
}
base = (char *)mp + mp->mp_upper;
len = ptr - mp->mp_upper + NODESIZE;
memmove(base - delta, base, len);
mp->mp_upper -= delta;
node = NODEPTR(mp, indx);
}
/* But even if no shift was needed, update ksize */
if (delta0)
node->mn_ksize = key->mv_size;
if (key->mv_size)
memcpy(NODEKEY(node), key->mv_data, key->mv_size);
return MDB_SUCCESS;
}
/** Move a node from csrc to cdst.
*/
static int
mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst)
{
int rc;
MDB_node *srcnode;
MDB_val key, data;
pgno_t srcpg;
unsigned short flags;
DKBUF;
/* Mark src and dst as dirty. */
if ((rc = mdb_page_touch(csrc)) ||
(rc = mdb_page_touch(cdst)))
return rc;
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0); /* fake */
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
data.mv_size = 0;
data.mv_data = NULL;
srcpg = 0;
flags = 0;
} else {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);
assert(!((long)srcnode&1));
srcpg = NODEPGNO(srcnode);
flags = srcnode->mn_flags;
if (csrc->mc_ki[csrc->mc_top] == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
unsigned int snum = csrc->mc_snum;
MDB_node *s2;
/* must find the lowest key below src */
mdb_page_search_root(csrc, NULL, 0);
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
} else {
s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
key.mv_size = NODEKSZ(s2);
key.mv_data = NODEKEY(s2);
}
csrc->mc_snum = snum--;
csrc->mc_top = snum;
} else {
key.mv_size = NODEKSZ(srcnode);
key.mv_data = NODEKEY(srcnode);
}
data.mv_size = NODEDSZ(srcnode);
data.mv_data = NODEDATA(srcnode);
}
if (IS_BRANCH(cdst->mc_pg[cdst->mc_top]) && cdst->mc_ki[cdst->mc_top] == 0) {
unsigned int snum = cdst->mc_snum;
MDB_node *s2;
MDB_val bkey;
/* must find the lowest key below dst */
mdb_page_search_root(cdst, NULL, 0);
if (IS_LEAF2(cdst->mc_pg[cdst->mc_top])) {
bkey.mv_size = cdst->mc_db->md_pad;
bkey.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, bkey.mv_size);
} else {
s2 = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
bkey.mv_size = NODEKSZ(s2);
bkey.mv_data = NODEKEY(s2);
}
cdst->mc_snum = snum--;
cdst->mc_top = snum;
rc = mdb_update_key(cdst->mc_pg[cdst->mc_top], 0, &bkey);
}
DPRINTF("moving %s node %u [%s] on page %zu to node %u on page %zu",
IS_LEAF(csrc->mc_pg[csrc->mc_top]) ? "leaf" : "branch",
csrc->mc_ki[csrc->mc_top],
DKEY(&key),
csrc->mc_pg[csrc->mc_top]->mp_pgno,
cdst->mc_ki[cdst->mc_top], cdst->mc_pg[cdst->mc_top]->mp_pgno);
/* Add the node to the destination page.
*/
rc = mdb_node_add(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, srcpg, flags);
if (rc != MDB_SUCCESS)
return rc;
/* Delete the node from the source page.
*/
mdb_node_del(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = csrc->mc_dbi;
MDB_page *mp = csrc->mc_pg[csrc->mc_top];
if (csrc->mc_flags & C_SUB)
dbi--;
for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (m2 == csrc) continue;
if (csrc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3->mc_pg[csrc->mc_top] == mp && m3->mc_ki[csrc->mc_top] ==
csrc->mc_ki[csrc->mc_top]) {
m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
}
}
}
/* Update the parent separators.
*/
if (csrc->mc_ki[csrc->mc_top] == 0) {
if (csrc->mc_ki[csrc->mc_top-1] != 0) {
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
} else {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
key.mv_size = NODEKSZ(srcnode);
key.mv_data = NODEKEY(srcnode);
}
DPRINTF("update separator for source page %zu to [%s]",
csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key));
if ((rc = mdb_update_key(csrc->mc_pg[csrc->mc_top-1], csrc->mc_ki[csrc->mc_top-1],
&key)) != MDB_SUCCESS)
return rc;
}
if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
MDB_val nullkey;
nullkey.mv_size = 0;
rc = mdb_update_key(csrc->mc_pg[csrc->mc_top], 0, &nullkey);
assert(rc == MDB_SUCCESS);
}
}
if (cdst->mc_ki[cdst->mc_top] == 0) {
if (cdst->mc_ki[cdst->mc_top-1] != 0) {
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, key.mv_size);
} else {
srcnode = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
key.mv_size = NODEKSZ(srcnode);
key.mv_data = NODEKEY(srcnode);
}
DPRINTF("update separator for destination page %zu to [%s]",
cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key));
if ((rc = mdb_update_key(cdst->mc_pg[cdst->mc_top-1], cdst->mc_ki[cdst->mc_top-1],
&key)) != MDB_SUCCESS)
return rc;
}
if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {
MDB_val nullkey;
nullkey.mv_size = 0;
rc = mdb_update_key(cdst->mc_pg[cdst->mc_top], 0, &nullkey);
assert(rc == MDB_SUCCESS);
}
}
return MDB_SUCCESS;
}
/** Merge one page into another.
* The nodes from the page pointed to by \b csrc will
* be copied to the page pointed to by \b cdst and then
* the \b csrc page will be freed.
* @param[in] csrc Cursor pointing to the source page.
* @param[in] cdst Cursor pointing to the destination page.
*/
static int
mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
{
int rc;
indx_t i, j;
MDB_node *srcnode;
MDB_val key, data;
unsigned nkeys;
DPRINTF("merging page %zu into %zu", csrc->mc_pg[csrc->mc_top]->mp_pgno,
cdst->mc_pg[cdst->mc_top]->mp_pgno);
assert(csrc->mc_snum > 1); /* can't merge root page */
assert(cdst->mc_snum > 1);
/* Mark dst as dirty. */
if ((rc = mdb_page_touch(cdst)))
return rc;
/* Move all nodes from src to dst.
*/
j = nkeys = NUMKEYS(cdst->mc_pg[cdst->mc_top]);
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = METADATA(csrc->mc_pg[csrc->mc_top]);
for (i = 0; i < NUMKEYS(csrc->mc_pg[csrc->mc_top]); i++, j++) {
rc = mdb_node_add(cdst, j, &key, NULL, 0, 0);
if (rc != MDB_SUCCESS)
return rc;
key.mv_data = (char *)key.mv_data + key.mv_size;
}
} else {
for (i = 0; i < NUMKEYS(csrc->mc_pg[csrc->mc_top]); i++, j++) {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], i);
if (i == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
unsigned int snum = csrc->mc_snum;
MDB_node *s2;
/* must find the lowest key below src */
mdb_page_search_root(csrc, NULL, 0);
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
} else {
s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
key.mv_size = NODEKSZ(s2);
key.mv_data = NODEKEY(s2);
}
csrc->mc_snum = snum--;
csrc->mc_top = snum;
} else {
key.mv_size = srcnode->mn_ksize;
key.mv_data = NODEKEY(srcnode);
}
data.mv_size = NODEDSZ(srcnode);
data.mv_data = NODEDATA(srcnode);
rc = mdb_node_add(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);
if (rc != MDB_SUCCESS)
return rc;
}
}
DPRINTF("dst page %zu now has %u keys (%.1f%% filled)",
cdst->mc_pg[cdst->mc_top]->mp_pgno, NUMKEYS(cdst->mc_pg[cdst->mc_top]), (float)PAGEFILL(cdst->mc_txn->mt_env, cdst->mc_pg[cdst->mc_top]) / 10);
/* Unlink the src page from parent and add to free list.
*/
mdb_node_del(csrc->mc_pg[csrc->mc_top-1], csrc->mc_ki[csrc->mc_top-1], 0);
if (csrc->mc_ki[csrc->mc_top-1] == 0) {
key.mv_size = 0;
if ((rc = mdb_update_key(csrc->mc_pg[csrc->mc_top-1], 0, &key)) != MDB_SUCCESS)
return rc;
}
mdb_midl_append(&csrc->mc_txn->mt_free_pgs, csrc->mc_pg[csrc->mc_top]->mp_pgno);
if (IS_LEAF(csrc->mc_pg[csrc->mc_top]))
csrc->mc_db->md_leaf_pages--;
else
csrc->mc_db->md_branch_pages--;
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = csrc->mc_dbi;
MDB_page *mp = cdst->mc_pg[cdst->mc_top];
if (csrc->mc_flags & C_SUB)
dbi--;
for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (csrc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == csrc) continue;
if (m3->mc_snum < csrc->mc_snum) continue;
if (m3->mc_pg[csrc->mc_top] == csrc->mc_pg[csrc->mc_top]) {
m3->mc_pg[csrc->mc_top] = mp;
m3->mc_ki[csrc->mc_top] += nkeys;
}
}
}
mdb_cursor_pop(csrc);
return mdb_rebalance(csrc);
}
/** Copy the contents of a cursor.
* @param[in] csrc The cursor to copy from.
* @param[out] cdst The cursor to copy to.
*/
static void
mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst)
{
unsigned int i;
cdst->mc_txn = csrc->mc_txn;
cdst->mc_dbi = csrc->mc_dbi;
cdst->mc_db = csrc->mc_db;
cdst->mc_dbx = csrc->mc_dbx;
cdst->mc_snum = csrc->mc_snum;
cdst->mc_top = csrc->mc_top;
cdst->mc_flags = csrc->mc_flags;
for (i=0; i<csrc->mc_snum; i++) {
cdst->mc_pg[i] = csrc->mc_pg[i];
cdst->mc_ki[i] = csrc->mc_ki[i];
}
}
/** Rebalance the tree after a delete operation.
* @param[in] mc Cursor pointing to the page where rebalancing
* should begin.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_rebalance(MDB_cursor *mc)
{
MDB_node *node;
int rc;
unsigned int ptop;
MDB_cursor mn;
#if MDB_DEBUG
{
pgno_t pgno;
COPY_PGNO(pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
DPRINTF("rebalancing %s page %zu (has %u keys, %.1f%% full)",
IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",
pgno, NUMKEYS(mc->mc_pg[mc->mc_top]), (float)PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) / 10);
}
#endif
if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= FILL_THRESHOLD) {
#if MDB_DEBUG
pgno_t pgno;
COPY_PGNO(pgno, mc->mc_pg[mc->mc_top]->mp_pgno);
DPRINTF("no need to rebalance page %zu, above fill threshold",
pgno);
#endif
return MDB_SUCCESS;
}
if (mc->mc_snum < 2) {
MDB_page *mp = mc->mc_pg[0];
if (NUMKEYS(mp) == 0) {
DPUTS("tree is completely empty");
mc->mc_db->md_root = P_INVALID;
mc->mc_db->md_depth = 0;
mc->mc_db->md_leaf_pages = 0;
mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
mc->mc_snum = 0;
mc->mc_top = 0;
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
if (mc->mc_flags & C_SUB)
dbi--;
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (m2 == mc) continue;
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3->mc_snum < mc->mc_snum) continue;
if (m3->mc_pg[0] == mp) {
m3->mc_snum = 0;
m3->mc_top = 0;
}
}
}
} else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {
DPUTS("collapsing root page!");
mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));
if ((rc = mdb_page_get(mc->mc_txn, mc->mc_db->md_root,
&mc->mc_pg[0])))
return rc;
mc->mc_db->md_depth--;
mc->mc_db->md_branch_pages--;
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
if (mc->mc_flags & C_SUB)
dbi--;
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (m2 == mc) continue;
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3->mc_snum < mc->mc_snum) continue;
if (m3->mc_pg[0] == mp) {
m3->mc_pg[0] = mc->mc_pg[0];
}
}
}
} else
DPUTS("root page doesn't need rebalancing");
return MDB_SUCCESS;
}
/* The parent (branch page) must have at least 2 pointers,
* otherwise the tree is invalid.
*/
ptop = mc->mc_top-1;
assert(NUMKEYS(mc->mc_pg[ptop]) > 1);
/* Leaf page fill factor is below the threshold.
* Try to move keys from left or right neighbor, or
* merge with a neighbor page.
*/
/* Find neighbors.
*/
mdb_cursor_copy(mc, &mn);
mn.mc_xcursor = NULL;
if (mc->mc_ki[ptop] == 0) {
/* We're the leftmost leaf in our parent.
*/
DPUTS("reading right neighbor");
mn.mc_ki[ptop]++;
node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mn.mc_pg[mn.mc_top])))
return rc;
mn.mc_ki[mn.mc_top] = 0;
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
} else {
/* There is at least one neighbor to the left.
*/
DPUTS("reading left neighbor");
mn.mc_ki[ptop]--;
node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mn.mc_pg[mn.mc_top])))
return rc;
mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;
mc->mc_ki[mc->mc_top] = 0;
}
DPRINTF("found neighbor page %zu (%u keys, %.1f%% full)",
mn.mc_pg[mn.mc_top]->mp_pgno, NUMKEYS(mn.mc_pg[mn.mc_top]), (float)PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) / 10);
/* If the neighbor page is above threshold and has at least two
* keys, move one key from it.
*
* Otherwise we should try to merge them.
*/
if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= FILL_THRESHOLD && NUMKEYS(mn.mc_pg[mn.mc_top]) >= 2)
return mdb_node_move(&mn, mc);
else { /* FIXME: if (has_enough_room()) */
mc->mc_flags &= ~C_INITIALIZED;
if (mc->mc_ki[ptop] == 0)
return mdb_page_merge(&mn, mc);
else
return mdb_page_merge(mc, &mn);
}
}
/** Complete a delete operation started by #mdb_cursor_del(). */
static int
mdb_cursor_del0(MDB_cursor *mc, MDB_node *leaf)
{
int rc;
/* add overflow pages to free list */
if (!IS_LEAF2(mc->mc_pg[mc->mc_top]) && F_ISSET(leaf->mn_flags, F_BIGDATA)) {
int i, ovpages;
pgno_t pg;
memcpy(&pg, NODEDATA(leaf), sizeof(pg));
ovpages = OVPAGES(NODEDSZ(leaf), mc->mc_txn->mt_env->me_psize);
mc->mc_db->md_overflow_pages -= ovpages;
for (i=0; i<ovpages; i++) {
DPRINTF("freed ov page %zu", pg);
mdb_midl_append(&mc->mc_txn->mt_free_pgs, pg);
pg++;
}
}
mdb_node_del(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], mc->mc_db->md_pad);
mc->mc_db->md_entries--;
rc = mdb_rebalance(mc);
if (rc != MDB_SUCCESS)
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
int
mdb_del(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data)
{
MDB_cursor mc;
MDB_xcursor mx;
MDB_cursor_op op;
MDB_val rdata, *xdata;
int rc, exact;
DKBUF;
assert(key != NULL);
DPRINTF("====> delete db %u key [%s]", dbi, DKEY(key));
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
return EACCES;
}
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
mdb_cursor_init(&mc, txn, dbi, &mx);
exact = 0;
if (data) {
op = MDB_GET_BOTH;
rdata = *data;
xdata = &rdata;
} else {
op = MDB_SET;
xdata = NULL;
}
rc = mdb_cursor_set(&mc, key, xdata, op, &exact);
if (rc == 0)
rc = mdb_cursor_del(&mc, data ? 0 : MDB_NODUPDATA);
return rc;
}
/** Split a page and insert a new node.
* @param[in,out] mc Cursor pointing to the page and desired insertion index.
* The cursor will be updated to point to the actual page and index where
* the node got inserted after the split.
* @param[in] newkey The key for the newly inserted node.
* @param[in] newdata The data for the newly inserted node.
* @param[in] newpgno The page number, if the new node is a branch node.
* @param[in] nflags The #NODE_ADD_FLAGS for the new node.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno,
unsigned int nflags)
{
unsigned int flags;
int rc = MDB_SUCCESS, ins_new = 0, new_root = 0, newpos = 1, did_split = 0;
indx_t newindx;
pgno_t pgno = 0;
unsigned int i, j, split_indx, nkeys, pmax;
MDB_node *node;
MDB_val sepkey, rkey, xdata, *rdata = &xdata;
MDB_page *copy;
MDB_page *mp, *rp, *pp;
unsigned int ptop;
MDB_cursor mn;
DKBUF;
mp = mc->mc_pg[mc->mc_top];
newindx = mc->mc_ki[mc->mc_top];
DPRINTF("-----> splitting %s page %zu and adding [%s] at index %i",
IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,
DKEY(newkey), mc->mc_ki[mc->mc_top]);
/* Create a right sibling. */
if ((rc = mdb_page_new(mc, mp->mp_flags, 1, &rp)))
return rc;
DPRINTF("new right sibling: page %zu", rp->mp_pgno);
if (mc->mc_snum < 2) {
if ((rc = mdb_page_new(mc, P_BRANCH, 1, &pp)))
return rc;
/* shift current top to make room for new parent */
mc->mc_pg[1] = mc->mc_pg[0];
mc->mc_ki[1] = mc->mc_ki[0];
mc->mc_pg[0] = pp;
mc->mc_ki[0] = 0;
mc->mc_db->md_root = pp->mp_pgno;
DPRINTF("root split! new root = %zu", pp->mp_pgno);
mc->mc_db->md_depth++;
new_root = 1;
/* Add left (implicit) pointer. */
if ((rc = mdb_node_add(mc, 0, NULL, NULL, mp->mp_pgno, 0)) != MDB_SUCCESS) {
/* undo the pre-push */
mc->mc_pg[0] = mc->mc_pg[1];
mc->mc_ki[0] = mc->mc_ki[1];
mc->mc_db->md_root = mp->mp_pgno;
mc->mc_db->md_depth--;
return rc;
}
mc->mc_snum = 2;
mc->mc_top = 1;
ptop = 0;
} else {
ptop = mc->mc_top-1;
DPRINTF("parent branch page is %zu", mc->mc_pg[ptop]->mp_pgno);
}
mc->mc_flags |= C_SPLITTING;
mdb_cursor_copy(mc, &mn);
mn.mc_pg[mn.mc_top] = rp;
mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;
if (nflags & MDB_APPEND) {
mn.mc_ki[mn.mc_top] = 0;
sepkey = *newkey;
split_indx = newindx;
nkeys = 0;
goto newsep;
}
nkeys = NUMKEYS(mp);
split_indx = nkeys / 2;
if (newindx < split_indx)
newpos = 0;
if (IS_LEAF2(rp)) {
char *split, *ins;
int x;
unsigned int lsize, rsize, ksize;
/* Move half of the keys to the right sibling */
copy = NULL;
x = mc->mc_ki[mc->mc_top] - split_indx;
ksize = mc->mc_db->md_pad;
split = LEAF2KEY(mp, split_indx, ksize);
rsize = (nkeys - split_indx) * ksize;
lsize = (nkeys - split_indx) * sizeof(indx_t);
mp->mp_lower -= lsize;
rp->mp_lower += lsize;
mp->mp_upper += rsize - lsize;
rp->mp_upper -= rsize - lsize;
sepkey.mv_size = ksize;
if (newindx == split_indx) {
sepkey.mv_data = newkey->mv_data;
} else {
sepkey.mv_data = split;
}
if (x<0) {
ins = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], ksize);
memcpy(rp->mp_ptrs, split, rsize);
sepkey.mv_data = rp->mp_ptrs;
memmove(ins+ksize, ins, (split_indx - mc->mc_ki[mc->mc_top]) * ksize);
memcpy(ins, newkey->mv_data, ksize);
mp->mp_lower += sizeof(indx_t);
mp->mp_upper -= ksize - sizeof(indx_t);
} else {
if (x)
memcpy(rp->mp_ptrs, split, x * ksize);
ins = LEAF2KEY(rp, x, ksize);
memcpy(ins, newkey->mv_data, ksize);
memcpy(ins+ksize, split + x * ksize, rsize - x * ksize);
rp->mp_lower += sizeof(indx_t);
rp->mp_upper -= ksize - sizeof(indx_t);
mc->mc_ki[mc->mc_top] = x;
mc->mc_pg[mc->mc_top] = rp;
}
goto newsep;
}
/* For leaf pages, check the split point based on what
* fits where, since otherwise mdb_node_add can fail.
*
* This check is only needed when the data items are
* relatively large, such that being off by one will
* make the difference between success or failure.
*
* It's also relevant if a page happens to be laid out
* such that one half of its nodes are all "small" and
* the other half of its nodes are "large." If the new
* item is also "large" and falls on the half with
* "large" nodes, it also may not fit.
*/
if (IS_LEAF(mp)) {
unsigned int psize, nsize;
/* Maximum free space in an empty page */
pmax = mc->mc_txn->mt_env->me_psize - PAGEHDRSZ;
nsize = mdb_leaf_size(mc->mc_txn->mt_env, newkey, newdata);
if ((nkeys < 20) || (nsize > pmax/16)) {
if (newindx <= split_indx) {
psize = nsize;
newpos = 0;
for (i=0; i<split_indx; i++) {
node = NODEPTR(mp, i);
psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
if (F_ISSET(node->mn_flags, F_BIGDATA))
psize += sizeof(pgno_t);
else
psize += NODEDSZ(node);
psize += psize & 1;
if (psize > pmax) {
if (i <= newindx) {
split_indx = newindx;
if (i < newindx)
newpos = 1;
}
else
split_indx = i;
break;
}
}
} else {
psize = nsize;
for (i=nkeys-1; i>=split_indx; i--) {
node = NODEPTR(mp, i);
psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
if (F_ISSET(node->mn_flags, F_BIGDATA))
psize += sizeof(pgno_t);
else
psize += NODEDSZ(node);
psize += psize & 1;
if (psize > pmax) {
if (i >= newindx) {
split_indx = newindx;
newpos = 0;
} else
split_indx = i+1;
break;
}
}
}
}
}
/* First find the separating key between the split pages.
* The case where newindx == split_indx is ambiguous; the
* new item could go to the new page or stay on the original
* page. If newpos == 1 it goes to the new page.
*/
if (newindx == split_indx && newpos) {
sepkey.mv_size = newkey->mv_size;
sepkey.mv_data = newkey->mv_data;
} else {
node = NODEPTR(mp, split_indx);
sepkey.mv_size = node->mn_ksize;
sepkey.mv_data = NODEKEY(node);
}
newsep:
DPRINTF("separator is [%s]", DKEY(&sepkey));
/* Copy separator key to the parent.
*/
if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(mc->mc_txn->mt_env, &sepkey)) {
mn.mc_snum--;
mn.mc_top--;
did_split = 1;
rc = mdb_page_split(&mn, &sepkey, NULL, rp->mp_pgno, 0);
/* root split? */
if (mn.mc_snum == mc->mc_snum) {
mc->mc_pg[mc->mc_snum] = mc->mc_pg[mc->mc_top];
mc->mc_ki[mc->mc_snum] = mc->mc_ki[mc->mc_top];
mc->mc_pg[mc->mc_top] = mc->mc_pg[ptop];
mc->mc_ki[mc->mc_top] = mc->mc_ki[ptop];
mc->mc_snum++;
mc->mc_top++;
ptop++;
}
/* Right page might now have changed parent.
* Check if left page also changed parent.
*/
if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
for (i=0; i<ptop; i++) {
mc->mc_pg[i] = mn.mc_pg[i];
mc->mc_ki[i] = mn.mc_ki[i];
}
mc->mc_pg[ptop] = mn.mc_pg[ptop];
mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
}
} else {
mn.mc_top--;
rc = mdb_node_add(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);
mn.mc_top++;
}
mc->mc_flags ^= C_SPLITTING;
if (rc != MDB_SUCCESS) {
return rc;
}
if (nflags & MDB_APPEND) {
mc->mc_pg[mc->mc_top] = rp;
mc->mc_ki[mc->mc_top] = 0;
rc = mdb_node_add(mc, 0, newkey, newdata, newpgno, nflags);
if (rc)
return rc;
for (i=0; i<mc->mc_top; i++)
mc->mc_ki[i] = mn.mc_ki[i];
goto done;
}
if (IS_LEAF2(rp)) {
goto done;
}
/* Move half of the keys to the right sibling. */
/* grab a page to hold a temporary copy */
copy = mdb_page_malloc(mc);
if (copy == NULL)
return ENOMEM;
copy->mp_pgno = mp->mp_pgno;
copy->mp_flags = mp->mp_flags;
copy->mp_lower = PAGEHDRSZ;
copy->mp_upper = mc->mc_txn->mt_env->me_psize;
mc->mc_pg[mc->mc_top] = copy;
for (i = j = 0; i <= nkeys; j++) {
if (i == split_indx) {
/* Insert in right sibling. */
/* Reset insert index for right sibling. */
if (i != newindx || (newpos ^ ins_new)) {
j = 0;
mc->mc_pg[mc->mc_top] = rp;
}
}
if (i == newindx && !ins_new) {
/* Insert the original entry that caused the split. */
rkey.mv_data = newkey->mv_data;
rkey.mv_size = newkey->mv_size;
if (IS_LEAF(mp)) {
rdata = newdata;
} else
pgno = newpgno;
flags = nflags;
ins_new = 1;
/* Update index for the new key. */
mc->mc_ki[mc->mc_top] = j;
} else if (i == nkeys) {
break;
} else {
node = NODEPTR(mp, i);
rkey.mv_data = NODEKEY(node);
rkey.mv_size = node->mn_ksize;
if (IS_LEAF(mp)) {
xdata.mv_data = NODEDATA(node);
xdata.mv_size = NODEDSZ(node);
rdata = &xdata;
} else
pgno = NODEPGNO(node);
flags = node->mn_flags;
i++;
}
if (!IS_LEAF(mp) && j == 0) {
/* First branch index doesn't need key data. */
rkey.mv_size = 0;
}
rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);
if (rc) break;
}
nkeys = NUMKEYS(copy);
for (i=0; i<nkeys; i++)
mp->mp_ptrs[i] = copy->mp_ptrs[i];
mp->mp_lower = copy->mp_lower;
mp->mp_upper = copy->mp_upper;
memcpy(NODEPTR(mp, nkeys-1), NODEPTR(copy, nkeys-1),
mc->mc_txn->mt_env->me_psize - copy->mp_upper);
/* reset back to original page */
if (newindx < split_indx || (!newpos && newindx == split_indx)) {
mc->mc_pg[mc->mc_top] = mp;
if (nflags & MDB_RESERVE) {
node = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (!(node->mn_flags & F_BIGDATA))
newdata->mv_data = NODEDATA(node);
}
} else {
mc->mc_ki[ptop]++;
}
/* return tmp page to freelist */
copy->mp_next = mc->mc_txn->mt_env->me_dpages;
VGMEMP_FREE(mc->mc_txn->mt_env, copy);
mc->mc_txn->mt_env->me_dpages = copy;
done:
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
int fixup = NUMKEYS(mp);
if (mc->mc_flags & C_SUB)
dbi--;
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (m2 == mc) continue;
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (!(m3->mc_flags & C_INITIALIZED))
continue;
if (m3->mc_flags & C_SPLITTING)
continue;
if (new_root) {
int k;
/* root split */
for (k=m3->mc_top; k>=0; k--) {
m3->mc_ki[k+1] = m3->mc_ki[k];
m3->mc_pg[k+1] = m3->mc_pg[k];
}
if (m3->mc_ki[0] >= split_indx) {
m3->mc_ki[0] = 1;
} else {
m3->mc_ki[0] = 0;
}
m3->mc_pg[0] = mc->mc_pg[0];
m3->mc_snum++;
m3->mc_top++;
}
if (m3->mc_pg[mc->mc_top] == mp) {
if (m3->mc_ki[mc->mc_top] >= newindx && !(nflags & MDB_SPLIT_REPLACE))
m3->mc_ki[mc->mc_top]++;
if (m3->mc_ki[mc->mc_top] >= fixup) {
m3->mc_pg[mc->mc_top] = rp;
m3->mc_ki[mc->mc_top] -= fixup;
m3->mc_ki[ptop] = mn.mc_ki[ptop];
}
} else if (!did_split && m3->mc_pg[ptop] == mc->mc_pg[ptop] &&
m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {
m3->mc_ki[ptop]++;
}
}
}
return rc;
}
int
mdb_put(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data, unsigned int flags)
{
MDB_cursor mc;
MDB_xcursor mx;
assert(key != NULL);
assert(data != NULL);
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
return EACCES;
}
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
if ((flags & (MDB_NOOVERWRITE|MDB_NODUPDATA|MDB_RESERVE|MDB_APPEND)) != flags)
return EINVAL;
mdb_cursor_init(&mc, txn, dbi, &mx);
return mdb_cursor_put(&mc, key, data, flags);
}
/** Only a subset of the @ref mdb_env flags can be changed
* at runtime. Changing other flags requires closing the environment
* and re-opening it with the new flags.
*/
#define CHANGEABLE (MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC)
int
mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)
{
if ((flag & CHANGEABLE) != flag)
return EINVAL;
if (onoff)
env->me_flags |= flag;
else
env->me_flags &= ~flag;
return MDB_SUCCESS;
}
int
mdb_env_get_flags(MDB_env *env, unsigned int *arg)
{
if (!env || !arg)
return EINVAL;
*arg = env->me_flags;
return MDB_SUCCESS;
}
int
mdb_env_get_path(MDB_env *env, const char **arg)
{
if (!env || !arg)
return EINVAL;
*arg = env->me_path;
return MDB_SUCCESS;
}
/** Common code for #mdb_stat() and #mdb_env_stat().
* @param[in] env the environment to operate in.
* @param[in] db the #MDB_db record containing the stats to return.
* @param[out] arg the address of an #MDB_stat structure to receive the stats.
* @return 0, this function always succeeds.
*/
static int
mdb_stat0(MDB_env *env, MDB_db *db, MDB_stat *arg)
{
arg->ms_psize = env->me_psize;
arg->ms_depth = db->md_depth;
arg->ms_branch_pages = db->md_branch_pages;
arg->ms_leaf_pages = db->md_leaf_pages;
arg->ms_overflow_pages = db->md_overflow_pages;
arg->ms_entries = db->md_entries;
return MDB_SUCCESS;
}
int
mdb_env_stat(MDB_env *env, MDB_stat *arg)
{
int toggle;
if (env == NULL || arg == NULL)
return EINVAL;
toggle = mdb_env_pick_meta(env);
return mdb_stat0(env, &env->me_metas[toggle]->mm_dbs[MAIN_DBI], arg);
}
/** Set the default comparison functions for a database.
* Called immediately after a database is opened to set the defaults.
* The user can then override them with #mdb_set_compare() or
* #mdb_set_dupsort().
* @param[in] txn A transaction handle returned by #mdb_txn_begin()
* @param[in] dbi A database handle returned by #mdb_open()
*/
static void
mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)
{
uint16_t f = txn->mt_dbs[dbi].md_flags;
txn->mt_dbxs[dbi].md_cmp =
(f & MDB_REVERSEKEY) ? mdb_cmp_memnr :
(f & MDB_INTEGERKEY) ? mdb_cmp_cint : mdb_cmp_memn;
txn->mt_dbxs[dbi].md_dcmp =
!(f & MDB_DUPSORT) ? 0 :
((f & MDB_INTEGERDUP)
? ((f & MDB_DUPFIXED) ? mdb_cmp_int : mdb_cmp_cint)
: ((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));
}
int mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
{
MDB_val key, data;
MDB_dbi i;
MDB_cursor mc;
int rc, dbflag, exact;
unsigned int unused = 0;
size_t len;
if (txn->mt_dbxs[FREE_DBI].md_cmp == NULL) {
mdb_default_cmp(txn, FREE_DBI);
}
/* main DB? */
if (!name) {
*dbi = MAIN_DBI;
if (flags & (MDB_DUPSORT|MDB_REVERSEKEY|MDB_INTEGERKEY))
txn->mt_dbs[MAIN_DBI].md_flags |= (flags & (MDB_DUPSORT|MDB_REVERSEKEY|MDB_INTEGERKEY));
mdb_default_cmp(txn, MAIN_DBI);
return MDB_SUCCESS;
}
if (txn->mt_dbxs[MAIN_DBI].md_cmp == NULL) {
mdb_default_cmp(txn, MAIN_DBI);
}
/* Is the DB already open? */
len = strlen(name);
for (i=2; i<txn->mt_numdbs; i++) {
if (!txn->mt_dbxs[i].md_name.mv_size) {
/* Remember this free slot */
if (!unused) unused = i;
continue;
}
if (len == txn->mt_dbxs[i].md_name.mv_size &&
!strncmp(name, txn->mt_dbxs[i].md_name.mv_data, len)) {
*dbi = i;
return MDB_SUCCESS;
}
}
/* If no free slot and max hit, fail */
if (!unused && txn->mt_numdbs >= txn->mt_env->me_maxdbs - 1)
return MDB_DBS_FULL;
/* Find the DB info */
dbflag = 0;
exact = 0;
key.mv_size = len;
key.mv_data = (void *)name;
mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
rc = mdb_cursor_set(&mc, &key, &data, MDB_SET, &exact);
if (rc == MDB_SUCCESS) {
/* make sure this is actually a DB */
MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);
if (!(node->mn_flags & F_SUBDATA))
return EINVAL;
} else if (rc == MDB_NOTFOUND && (flags & MDB_CREATE)) {
/* Create if requested */
MDB_db dummy;
data.mv_size = sizeof(MDB_db);
data.mv_data = &dummy;
memset(&dummy, 0, sizeof(dummy));
dummy.md_root = P_INVALID;
dummy.md_flags = flags & 0xffff;
rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA);
dbflag = DB_DIRTY;
}
/* OK, got info, add to table */
if (rc == MDB_SUCCESS) {
unsigned int slot = unused ? unused : txn->mt_numdbs;
txn->mt_dbxs[slot].md_name.mv_data = strdup(name);
txn->mt_dbxs[slot].md_name.mv_size = len;
txn->mt_dbxs[slot].md_rel = NULL;
txn->mt_dbflags[slot] = dbflag;
memcpy(&txn->mt_dbs[slot], data.mv_data, sizeof(MDB_db));
*dbi = slot;
txn->mt_env->me_dbflags[slot] = txn->mt_dbs[slot].md_flags;
mdb_default_cmp(txn, slot);
if (!unused) {
txn->mt_numdbs++;
txn->mt_env->me_numdbs++;
}
}
return rc;
}
int mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)
{
if (txn == NULL || arg == NULL || dbi >= txn->mt_numdbs)
return EINVAL;
return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);
}
void mdb_close(MDB_env *env, MDB_dbi dbi)
{
char *ptr;
if (dbi <= MAIN_DBI || dbi >= env->me_numdbs)
return;
ptr = env->me_dbxs[dbi].md_name.mv_data;
env->me_dbxs[dbi].md_name.mv_data = NULL;
env->me_dbxs[dbi].md_name.mv_size = 0;
free(ptr);
}
/** Add all the DB's pages to the free list.
* @param[in] mc Cursor on the DB to free.
* @param[in] subs non-Zero to check for sub-DBs in this DB.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_drop0(MDB_cursor *mc, int subs)
{
int rc;
rc = mdb_page_search(mc, NULL, 0);
if (rc == MDB_SUCCESS) {
MDB_node *ni;
MDB_cursor mx;
unsigned int i;
/* LEAF2 pages have no nodes, cannot have sub-DBs */
if (!subs || IS_LEAF2(mc->mc_pg[mc->mc_top]))
mdb_cursor_pop(mc);
mdb_cursor_copy(mc, &mx);
while (mc->mc_snum > 0) {
if (IS_LEAF(mc->mc_pg[mc->mc_top])) {
for (i=0; i<NUMKEYS(mc->mc_pg[mc->mc_top]); i++) {
ni = NODEPTR(mc->mc_pg[mc->mc_top], i);
if (ni->mn_flags & F_SUBDATA) {
mdb_xcursor_init1(mc, ni);
rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
if (rc)
return rc;
}
}
} else {
for (i=0; i<NUMKEYS(mc->mc_pg[mc->mc_top]); i++) {
pgno_t pg;
ni = NODEPTR(mc->mc_pg[mc->mc_top], i);
pg = NODEPGNO(ni);
/* free it */
mdb_midl_append(&mc->mc_txn->mt_free_pgs, pg);
}
}
if (!mc->mc_top)
break;
rc = mdb_cursor_sibling(mc, 1);
if (rc) {
/* no more siblings, go back to beginning
* of previous level. (stack was already popped
* by mdb_cursor_sibling)
*/
for (i=1; i<mc->mc_top; i++)
mc->mc_pg[i] = mx.mc_pg[i];
}
}
/* free it */
mdb_midl_append(&mc->mc_txn->mt_free_pgs,
mc->mc_db->md_root);
}
return 0;
}
int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
{
MDB_cursor *mc;
int rc;
if (!txn || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
return EACCES;
rc = mdb_cursor_open(txn, dbi, &mc);
if (rc)
return rc;
rc = mdb_drop0(mc, mc->mc_db->md_flags & MDB_DUPSORT);
if (rc)
goto leave;
/* Can't delete the main DB */
if (del && dbi > MAIN_DBI) {
rc = mdb_del(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL);
if (!rc)
mdb_close(txn->mt_env, dbi);
} else {
/* reset the DB record, mark it dirty */
txn->mt_dbflags[dbi] |= DB_DIRTY;
txn->mt_dbs[dbi].md_depth = 0;
txn->mt_dbs[dbi].md_branch_pages = 0;
txn->mt_dbs[dbi].md_leaf_pages = 0;
txn->mt_dbs[dbi].md_overflow_pages = 0;
txn->mt_dbs[dbi].md_entries = 0;
txn->mt_dbs[dbi].md_root = P_INVALID;
if (!txn->mt_u.dirty_list[0].mid) {
MDB_cursor m2;
MDB_val key, data;
/* make sure we have at least one dirty page in this txn
* otherwise these changes will be ignored.
*/
key.mv_size = sizeof(txnid_t);
key.mv_data = &txn->mt_txnid;
data.mv_size = sizeof(MDB_ID);
data.mv_data = txn->mt_free_pgs;
mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
rc = mdb_cursor_put(&m2, &key, &data, 0);
}
}
leave:
mdb_cursor_close(mc);
return rc;
}
int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
{
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
txn->mt_dbxs[dbi].md_cmp = cmp;
return MDB_SUCCESS;
}
int mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
{
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
txn->mt_dbxs[dbi].md_dcmp = cmp;
return MDB_SUCCESS;
}
int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel)
{
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
txn->mt_dbxs[dbi].md_rel = rel;
return MDB_SUCCESS;
}
int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx)
{
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
txn->mt_dbxs[dbi].md_relctx = ctx;
return MDB_SUCCESS;
}
/** @} */
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