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