stasis-aries-wal/stasis/logger/logWriter.h

101 lines
4 KiB
C

/*---
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The authors hereby grant permission to use, copy, modify, distribute,
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authorized uses. Modifications to this software may be copyrighted by
their authors and need not follow the licensing terms described here,
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
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THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, AND
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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.
---*/
/**
* @file
*
* New version of logstreamer; designed to work with logEntry, and has
* a simplified API.
*
* logstreamer is the implementation of writing the log tail
* It must be bufferred -- in that when something is written to the log tail it
* is not immediately written to disk, but rather just to memory. But
* logstreamer must be able to force flush to disk, which will be done when a
* commit log entry is written to the log tail
*
* Note: using the stdio FILEs for this, and by default it is "fully" buffered.
* The log tail may be flushed to disk without an explicit call to fflush (when
* the program terminates, the file closes), but this is acceptable because it
* never hurts to have more flushes to disk, as long as it doesn't hurt
* performance.
*
* @todo Everything in this file cores on failure (no error handling yet)
* @todo logWriter is optimized for forward operation, scanning backwards
* (as in abort()) is very slow. Perhaps we should maintian a
* 'write behind' buffer?
*
* $Id$
*
*/
#ifndef __LOGWRITER_H__
#define __LOGWRITER_H__
#include <stasis/common.h>
#include <stasis/logger/logger2.h>
#include <stasis/logger/logEntry.h>
BEGIN_C_DECLS
/**
Start a new log stream by opening the log file for reading. This
is stasis's default log implementation, and uses safe writes to
perform truncation.
@return NULL on error
*/
stasis_log_t* openLogWriter(const char * filename,
int filemode,
int fileperm);
/**
Actually deletes the log file that may have been written to disk! Danger!!
Only use after calling closeLogStream AND you are sure there are no active
(or future active) transactions!
@todo This only exists because the tests use it...once the logfile
name isn't hardcoded, remove this function.
*/
void deleteLogWriter();
END_C_DECLS
#endif /* __LLADD_LOGGER_LOGWRITER_H */