Add untested implementations of experimental APIs sqlite3_snapshot_get(), _open() and _free().
FossilOrigin-Name: 0715eb00aa8891400cd50a15509d3d7b13789626
diff --git a/src/main.c b/src/main.c
index d552f7f..902954b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3866,3 +3866,85 @@
pBt = sqlite3DbNameToBtree(db, zDbName);
return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
}
+
+#ifdef SQLITE_ENABLE_SNAPSHOT
+/*
+** Obtain a snapshot handle for the snapshot of database zDb currently
+** being read by handle db.
+*/
+int sqlite3_snapshot_get(
+ sqlite3 *db,
+ const char *zDb,
+ sqlite3_snapshot **ppSnapshot
+){
+ int rc = SQLITE_ERROR;
+#ifndef SQLITE_OMIT_WAL
+ int iDb;
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+ if( !sqlite3SafetyCheckOk(db) ){
+ return SQLITE_MISUSE_BKPT;
+ }
+#endif
+ sqlite3_mutex_enter(db->mutex);
+
+ iDb = sqlite3FindDbName(db, zDb);
+ if( iDb==0 || iDb>1 ){
+ Btree *pBt = db->aDb[iDb].pBt;
+ if( 0!=sqlite3BtreeIsInReadTrans(pBt)
+ && 0==sqlite3BtreeIsInTrans(pBt)
+ ){
+ rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
+ }
+ }
+
+ sqlite3_mutex_leave(db->mutex);
+#endif /* SQLITE_OMIT_WAL */
+ return rc;
+}
+
+/*
+** Open a read-transaction on the snapshot idendified by pSnapshot.
+*/
+int sqlite3_snapshot_open(
+ sqlite3 *db,
+ const char *zDb,
+ sqlite3_snapshot *pSnapshot
+){
+ int rc = SQLITE_ERROR;
+#ifndef SQLITE_OMIT_WAL
+
+#ifdef SQLITE_ENABLE_API_ARMOR
+ if( !sqlite3SafetyCheckOk(db) ){
+ return SQLITE_MISUSE_BKPT;
+ }
+#endif
+ sqlite3_mutex_enter(db->mutex);
+ if( db->autoCommit==0 ){
+ int iDb;
+ iDb = sqlite3FindDbName(db, zDb);
+ if( iDb==0 || iDb>1 ){
+ Btree *pBt = db->aDb[iDb].pBt;
+ if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
+ rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
+ if( rc==SQLITE_OK ){
+ rc = sqlite3BtreeBeginTrans(pBt, 0);
+ sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
+ }
+ }
+ }
+ }
+
+ sqlite3_mutex_leave(db->mutex);
+#endif /* SQLITE_OMIT_WAL */
+ return rc;
+}
+
+/*
+** Free a snapshot handle obtained from sqlite3_snapshot_get().
+*/
+void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
+ sqlite3_free(pSnapshot);
+}
+#endif /* SQLITE_ENABLE_SNAPSHOT */
+