stasis-aries-wal/src/lladd/operations/nestedTopActions.c

128 lines
5.5 KiB
C

/*---
This software is copyrighted by the Regents of the University of
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The authors hereby grant permission to use, copy, modify, distribute,
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provided that the new terms are clearly indicated on the first page of
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FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, AND
THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE
MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
GOVERNMENT USE: If you are acquiring this software on behalf of the
U.S. government, the Government shall have only "Restricted Rights" in
the software and related documentation as defined in the Federal
Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2). If you are
acquiring the software on behalf of the Department of Defense, the
software shall be classified as "Commercial Computer Software" and the
Government shall have only "Restricted Rights" as defined in Clause
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authors grant the U.S. Government and others acting in its behalf
permission to use and distribute the software in accordance with the
terms specified in this license.
---*/
/**********************************************
* $Id$
*
* Decrements the given reference by one
*********************************************/
#include <lladd/transactional.h>
#include <lladd/common.h>
#include <lladd/operations/nestedTopActions.h>
#include <lladd/logger/logger2.h>
#include <pbl/pbl.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
#include <assert.h>
/** @todo Remove extern declaration of transactional_2_mutex from nestedTopActions.c */
extern pthread_mutex_t transactional_2_mutex;
/*#include <lladd/bufferManager.h>*/
extern TransactionLog XactionTable[];
pblHashTable_t * nestedTopActions = NULL;
/** @todo this really should be set somewhere globally. */
void initNestedTopActions() {
nestedTopActions = pblHtCreate();
}
/** @todo TbeginNestedTopAction's API might not be quite right.
Are there cases where we need to pass a recordid in?
@return a handle that must be passed into TendNestedTopAction
*/
void * TbeginNestedTopAction(int xid, int op, const byte * dat, int datSize) {
recordid rid = NULLRID;
rid.page = datSize;
LogEntry * e = LogUpdate(&XactionTable[xid % MAX_TRANSACTIONS], NULL, rid, op, dat);
DEBUG("Begin Nested Top Action e->LSN: %ld\n", e->LSN);
lsn_t * prevLSN = malloc(sizeof(lsn_t));
*prevLSN = e->LSN;
pthread_mutex_lock(&transactional_2_mutex);
void * ret = pblHtLookup(nestedTopActions, &xid, sizeof(int));
if(ret) {
pblHtRemove(nestedTopActions, &xid, sizeof(int));
}
pblHtInsert(nestedTopActions, &xid, sizeof(int), prevLSN);
pthread_mutex_unlock(&transactional_2_mutex);
FreeLogEntry(e);
return ret;
}
/**
Call this function at the end of a nested top action.
@return the lsn of the CLR. Most users (everyone?) will ignore this.
@todo LogCLR()'s API is useless. Make it private, and implement a better
public version. (Then rewrite TendNestedTopAction)
*/
lsn_t TendNestedTopAction(int xid, void * handle) {
pthread_mutex_lock(&transactional_2_mutex);
lsn_t * prevLSN = pblHtLookup(nestedTopActions, &xid, sizeof(int));
pblHtRemove(nestedTopActions, &xid, sizeof(int));
if(handle) {
pblHtInsert(nestedTopActions, &xid, sizeof(int), handle);
}
// This action wasn't really undone -- This is a nested top action!
lsn_t undoneLSN = XactionTable[xid % MAX_TRANSACTIONS].prevLSN;
recordid undoneRID = NULLRID; // Not correct, but this field is unused anyway. ;)
// Write a CLR.
lsn_t clrLSN = LogCLR(xid, undoneLSN, undoneRID, *prevLSN);
// Ensure that the next action in this transaction points to the CLR.
XactionTable[xid % MAX_TRANSACTIONS].prevLSN = clrLSN;
DEBUG("NestedTopAction CLR %d, LSN: %ld type: %ld (undoing: %ld, next to undo: %ld)\n", e->xid,
clrLSN, undoneLSN, *prevLSN);
free(prevLSN);
pthread_mutex_unlock(&transactional_2_mutex);
return clrLSN;
}