Change the behavior of the sqlite3_wal_hook() callback. It should now return

SQLITE_OK or an error code and the error code is propagated back up the 
stack.  If a checkpoint is desired, the callback should invoke
sqlite3_wal_callback() itself.

FossilOrigin-Name: 1b14195e05fe5551992a39246ec3bcf6a33bbfac

4 files changed, 26 insertions, 25 deletions

diff --git a/src/main.c b/src/main.c
index 962c857d6..4cd90663f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1189,19 +1189,20 @@ void *sqlite3_rollback_hook(
 #ifndef SQLITE_OMIT_WAL
 /*
 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
-** Return non-zero, indicating to the caller that a checkpoint should be run,
-** if the number of frames in the log file is greater than 
-** sqlite3.pWalArg cast to an integer (the value configured by
+** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
+** is greater than sqlite3.pWalArg cast to an integer (the value configured by
 ** wal_autocheckpoint()).
 */ 
 int sqlite3WalDefaultHook(
-  void *p,               /* Argument */
+  void *pClientData,     /* Argument */
   sqlite3 *db,           /* Connection */
-  const char *zNotUsed,  /* Database */
+  const char *zDb,       /* Database */
   int nFrame             /* Size of WAL */
 ){
-  UNUSED_PARAMETER(zNotUsed);
-  return ( nFrame>=SQLITE_PTR_TO_INT(p));
+  if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
+    sqlite3_wal_checkpoint(db, zDb);
+  }
+  return SQLITE_OK;
 }
 #endif /* SQLITE_OMIT_WAL */
 
@@ -1218,13 +1219,11 @@ int sqlite3WalDefaultHook(
 */
 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
 #ifndef SQLITE_OMIT_WAL
-  sqlite3_mutex_enter(db->mutex);
   if( nFrame>0 ){
     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
   }else{
     sqlite3_wal_hook(db, 0, 0);
   }
-  sqlite3_mutex_leave(db->mutex);
 #endif
   return SQLITE_OK;
 }
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 2672690b7..e59b02c74 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -5780,9 +5780,10 @@ void sqlite3_log(int iErrCode, const char *zFormat, ...);
 ** is the number of pages currently in the log file, including those that
 ** were just committed.
 **
-** If an invocation of the callback function returns non-zero, then a
-** checkpoint is automatically run on the database. If zero is returned,
-** no special action is taken.
+** The callback function should normally return SQLITE_OK.  If an error
+** code is returned, that error will propagate back up through the
+** SQLite code base to cause the statement that provoked the callback
+** to fail.
 **
 ** A single database handle may have at most a single log callback 
 ** registered at one time. Calling [sqlite3_wal_hook()] replaces any
diff --git a/src/tclsqlite.c b/src/tclsqlite.c
index d9d6a7d8a..d8d0fd2b9 100644
--- a/src/tclsqlite.c
+++ b/src/tclsqlite.c
@@ -123,7 +123,7 @@ struct SqliteDb {
   SqlFunc *pFunc;            /* List of SQL functions */
   Tcl_Obj *pUpdateHook;      /* Update hook script (if any) */
   Tcl_Obj *pRollbackHook;    /* Rollback hook script (if any) */
-  Tcl_Obj *pLogHook;         /* WAL hook script (if any) */
+  Tcl_Obj *pWalHook;         /* WAL hook script (if any) */
   Tcl_Obj *pUnlockNotify;    /* Unlock notify script (if any) */
   SqlCollate *pCollate;      /* List of SQL collation functions */
   int rc;                    /* Return code of most recent sqlite3_exec() */
@@ -486,8 +486,8 @@ static void DbDeleteCmd(void *db){
   if( pDb->pRollbackHook ){
     Tcl_DecrRefCount(pDb->pRollbackHook);
   }
-  if( pDb->pLogHook ){
-    Tcl_DecrRefCount(pDb->pLogHook);
+  if( pDb->pWalHook ){
+    Tcl_DecrRefCount(pDb->pWalHook);
   }
   if( pDb->pCollateNeeded ){
     Tcl_DecrRefCount(pDb->pCollateNeeded);
@@ -593,19 +593,22 @@ static void DbRollbackHandler(void *clientData){
   }
 }
 
-static int DbLogHandler(
+/*
+** This procedure handles wal_hook callbacks.
+*/
+static int DbWalHandler(
   void *clientData, 
   sqlite3 *db, 
   const char *zDb, 
   int nEntry
 ){
-  int ret = 0;
+  int ret = SQLITE_OK;
   Tcl_Obj *p;
   SqliteDb *pDb = (SqliteDb*)clientData;
   Tcl_Interp *interp = pDb->interp;
-  assert(pDb->pLogHook);
+  assert(pDb->pWalHook);
 
-  p = Tcl_DuplicateObj(pDb->pLogHook);
+  p = Tcl_DuplicateObj(pDb->pWalHook);
   Tcl_IncrRefCount(p);
   Tcl_ListObjAppendElement(interp, p, Tcl_NewStringObj(zDb, -1));
   Tcl_ListObjAppendElement(interp, p, Tcl_NewIntObj(nEntry));
@@ -2775,7 +2778,7 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
     if( choice==DB_UPDATE_HOOK ){
       ppHook = &pDb->pUpdateHook;
     }else if( choice==DB_WAL_HOOK ){
-      ppHook = &pDb->pLogHook;
+      ppHook = &pDb->pWalHook;
     }else{
       ppHook = &pDb->pRollbackHook;
     }
@@ -2801,7 +2804,7 @@ static int DbObjCmd(void *cd, Tcl_Interp *interp, int objc,Tcl_Obj *const*objv){
 
     sqlite3_update_hook(pDb->db, (pDb->pUpdateHook?DbUpdateHandler:0), pDb);
     sqlite3_rollback_hook(pDb->db,(pDb->pRollbackHook?DbRollbackHandler:0),pDb);
-    sqlite3_wal_hook(pDb->db,(pDb->pLogHook?DbLogHandler:0),pDb);
+    sqlite3_wal_hook(pDb->db,(pDb->pWalHook?DbWalHandler:0),pDb);
 
     break;
   }
diff --git a/src/vdbeapi.c b/src/vdbeapi.c
index 2a8c1dd18..2f5aaa36d 100644
--- a/src/vdbeapi.c
+++ b/src/vdbeapi.c
@@ -318,10 +318,8 @@ static int doWalCallbacks(sqlite3 *db){
     Btree *pBt = db->aDb[i].pBt;
     if( pBt ){
       int nEntry = sqlite3PagerWalCallback(sqlite3BtreePager(pBt));
-      if( db->xWalCallback && nEntry>0 && rc==SQLITE_OK
-       && db->xWalCallback(db->pWalArg, db, db->aDb[i].zName, nEntry)
-      ){
-        rc = sqlite3Checkpoint(db, i);
+      if( db->xWalCallback && nEntry>0 && rc==SQLITE_OK ){
+        rc = db->xWalCallback(db->pWalArg, db, db->aDb[i].zName, nEntry);
       }
     }
   }