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IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY 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 252.227-7013 (c) (1) of DFARs. Notwithstanding the foregoing, the 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. ---*/ /** * @file * * Interface to Stasis' log file. * * @ingroup LOGGING_DISCIPLINE * * $Id$ * */ #ifndef __LOGGER2_H__ #define __LOGGER2_H__ #include /** A callback function that allows logHandle's iterator to stop returning log entries depending on the context in which it was called. */ typedef int (guard_fcn_t)(const LogEntry *, void *); typedef struct stasis_log_t stasis_log_t; /** Contains the state needed by the logging layer to perform operations on a transaction. */ typedef struct { int xid; lsn_t prevLSN; lsn_t recLSN; } TransactionLog; /** This is the log implementation that is being used. Before Stasis is intialized it will be set to a default value. It may be changed before Tinit() is called by assigning to it. The default can be overridden at compile time by defining USE_LOGGER. (eg: gcc ... -DUSE_LOGGER=LOG_TO_FOO) @see constants.h for a list of recognized log implementations. (The constants are named LOG_TO_*) */ extern int loggerType; struct stasis_log_t { /** Needed by sizeofLogEntry */ lsn_t (*sizeof_internal_entry)(struct stasis_log_t* log, const LogEntry * e); /** Append a log entry to the end of the log. @param e This call sets e->LSN to entry's offset. @return 0 on success */ int (*write_entry)(struct stasis_log_t* log, LogEntry * e); /** Read a log entry, given its LSN. @param lsn The lsn of the log entry to be read. */ const LogEntry* (*read_entry)(struct stasis_log_t* log, lsn_t lsn); /** Given a log entry, return the LSN of the next entry. */ lsn_t (*next_entry)(struct stasis_log_t* log, const LogEntry * e); /** This function returns the LSN of the most recent log entry that has not been flushed to disk. If the entire log is flushed, this function returns the LSN of the entry that will be allocated the next time the log is appended to. */ lsn_t (*first_unstable_lsn)(struct stasis_log_t* log); /** Force any enqueued, unwritten entries to disk */ void (*force_tail)(struct stasis_log_t* log); /** @param lsn The first lsn that will be available after truncation. @return 0 on success */ int (*truncate)(struct stasis_log_t* log, lsn_t lsn); /** Returns the LSN of the first entry of the log. If the log is empty, return the LSN that will be assigned to the next log entry that is appended to the log. */ lsn_t (*truncation_point)(struct stasis_log_t* log); /** @return 0 on success */ int (*deinit)(struct stasis_log_t* log); int (*is_durable)(); }; /** @todo get rid of this! */ extern stasis_log_t* stasis_log_file; void LogForce(stasis_log_t* log, lsn_t lsn); /** Inform the logging layer that a new transaction has begun, and obtain a handle. */ TransactionLog LogTransBegin(stasis_log_t* log, int xid); /** Write a transaction PREPARE to the log tail. Blocks until the prepare record is stable. @return the lsn of the prepare log entry */ lsn_t LogTransPrepare(stasis_log_t* log, TransactionLog * l); /** Write a transaction COMMIT to the log tail. Blocks until the commit record is stable. @return the lsn of the commit log entry. */ lsn_t LogTransCommit(stasis_log_t* log, TransactionLog * l); /** Write a transaction ABORT to the log tail. Does not force the log. @return the lsn of the abort log entry. */ lsn_t LogTransAbort(stasis_log_t* log, TransactionLog * l); /** Write a end transaction record @see XEND @todo Implement LogEnd */ void LogEnd (stasis_log_t* log, TransactionLog * l); /** LogUpdate writes an UPDATELOG log record to the log tail. It also interprets its operation argument to the extent necessary for allocating and laying out the log entry. Finally, it updates the state of the parameter l. */ LogEntry * LogUpdate(stasis_log_t* log, TransactionLog * l, Page * p, unsigned int operation, const byte * arg, size_t arg_size); /** Write a compensation log record. These records are used to allow for efficient recovery, and possibly for log truncation. They record the completion of undo operations, amongst other things. @return the lsn of the CLR entry that was written to the log. (Needed so that the lsn slot of the page in question can be updated.) */ lsn_t LogCLR(stasis_log_t* log, const LogEntry * e); lsn_t LogDummyCLR(stasis_log_t* log, int xid, lsn_t prev_lsn, lsn_t compensated_lsn); #endif