stasis-aries-wal/src/lladd/logger/inMemoryLog.c

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2006-04-12 01:40:47 +00:00
#include "inMemoryLog.h"
#include <libdfa/rw.h>
#include <string.h>
#include <assert.h>
static rwl * flushedLSN_lock;
static lsn_t nextAvailableLSN;
static lsn_t globalOffset;
static rwl * globalOffset_lock;
static LogEntry ** buffer;
static lsn_t bufferLen;
int open_InMemoryLog() {
flushedLSN_lock = initlock();
globalOffset_lock = initlock();
globalOffset = 0;
nextAvailableLSN = 0;
buffer = malloc(4096 * 1024 * sizeof (LogEntry *));
bufferLen =4096 * 1024;
return 0;
}
int writeLogEntry_InMemoryLog(LogEntry *e) {
writelock(flushedLSN_lock, 0);
lsn_t bufferOffset;
int done = 0;
do{
readlock(globalOffset_lock,0);
bufferOffset = nextAvailableLSN - globalOffset;
if(bufferOffset > bufferLen) {
unlock(globalOffset_lock);
writelock(globalOffset_lock,0);
abort(); // really, need to extend log.
} else {
done = 1;
}
} while (!done);
e->LSN = nextAvailableLSN;
// printf ("lsn: %ld\n", e->LSN);
buffer[bufferOffset] = e;
// printf("lsn: %ld type: %d\n", e->LSN, e->type);
nextAvailableLSN++;
unlock(globalOffset_lock);
unlock(flushedLSN_lock);
return 0;
}
lsn_t flushedLSN_InMemoryLog() {
return nextAvailableLSN;
}
int truncateLog_InMemoryLog(lsn_t lsn) {
abort();
}
lsn_t firstLogEntry_InMemoryLog() {
return globalOffset;
}
void close_InMemoryLog() {
if(buffer) {
lsn_t firstEmptyOffset = nextAvailableLSN-globalOffset;
for(lsn_t i = 0; i < firstEmptyOffset; i++) {
assert(buffer[i]->LSN == i+globalOffset);
free(buffer[i]);
}
free(buffer);
nextAvailableLSN = 0;
globalOffset = 0;
bufferLen = 0;
buffer = 0;
}
}
LogEntry * readLSNEntry_InMemoryLog(lsn_t LSN) {
// printf("lsn: %ld\n", LSN);
if(LSN >= nextAvailableLSN) { return 0; }
assert(LSN-globalOffset >= 0 && LSN-globalOffset< bufferLen);
readlock(globalOffset_lock, 0);
LogEntry * ptr = buffer[LSN - globalOffset];
unlock(globalOffset_lock);
assert(ptr);
assert(ptr->LSN == LSN);
//printf("lsn: %ld prevlsn: %ld\n", ptr->LSN, ptr->prevLSN);
return ptr;
}