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Add the sqlite3_snapshot_cmp() API.

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FossilOrigin-Name: c698a21af740ca1019c3a771fb83e569cd6bf23e
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dan
2016-04-11 19:59:52 +00:00
parent 244b9d6ec6
commit ad2d5baf1f
6 changed files with 112 additions and 11 deletions
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17
src/wal.c
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@@ -3399,6 +3399,23 @@ int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot){
void sqlite3WalSnapshotOpen(Wal *pWal, sqlite3_snapshot *pSnapshot){
pWal->pSnapshot = (WalIndexHdr*)pSnapshot;
}
/*
** Return a +ve value if snapshot p1 is newer than p2. A -ve value if
** p1 is older than p2 and zero if p1 and p2 are the same snapshot.
*/
int sqlite3_snapshot_cmp(sqlite3_snapshot *p1, sqlite3_snapshot *p2){
WalIndexHdr *pHdr1 = (WalIndexHdr*)p1;
WalIndexHdr *pHdr2 = (WalIndexHdr*)p2;
/* aSalt[0] is a copy of the value stored in the wal file header. It
** is incremented each time the wal file is restarted. */
if( pHdr1->aSalt[0]<pHdr2->aSalt[0] ) return -1;
if( pHdr1->aSalt[0]>pHdr2->aSalt[0] ) return +1;
if( pHdr1->mxFrame<pHdr2->mxFrame ) return -1;
if( pHdr1->mxFrame>pHdr2->mxFrame ) return +1;
return 0;
}
#endif /* SQLITE_ENABLE_SNAPSHOT */
#ifdef SQLITE_ENABLE_ZIPVFS