SQLite

  if( db->lookaside.bMalloced ){
    sqlite3_free(db->lookaside.pStart);
  }
  sqlite3_free(db);
  return SQLITE_OK;
}


/*
** Invoke the transaction-hook.
*/
void sqlite3TransactionHook(sqlite3 *db, int op, int iLevel){
  assert( op==SQLITE_BEGIN || op==SQLITE_COMMIT || op==SQLITE_ROLLBACK );
  assert( op==SQLITE_BEGIN || iLevel<db->iOpenTrans || iLevel==0 );
  assert( op==SQLITE_BEGIN || iLevel<db->iOpenTrans || db->iOpenTrans==0 );
  assert( op!=SQLITE_BEGIN || iLevel==db->iOpenTrans || iLevel==0 );
  assert( op!=SQLITE_BEGIN || iLevel==db->iOpenTrans || db->iOpenTrans==1 );

  if( op==SQLITE_BEGIN && iLevel!=db->iOpenTrans ) return;
  if( op!=SQLITE_BEGIN && iLevel>=db->iOpenTrans ) return;

  if( db->xTransCallback ){
    db->xTransCallback(db->pTransArg, op, iLevel);
  }
  db->iOpenTrans = iLevel + (op==SQLITE_BEGIN);
}

/*
** Rollback all database files.
*/
void sqlite3RollbackAll(sqlite3 *db){
  int i;
  int inTrans = 0;
  assert( sqlite3_mutex_held(db->mutex) );

  /* Any deferred constraint violations have now been resolved. */
  db->nDeferredCons = 0;

  /* If one has been configured, invoke the rollback-hook callback */
  if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
    db->xRollbackCallback(db->pRollbackArg);
  }

  /* If a transaction-hook is configured, invoke it now to report on 
  ** the rollback operation. */
  sqlite3TransactionHook(db, SQLITE_ROLLBACK, 0);
}

/*
** Return a static string that describes the kind of error specified in the
** argument.
*/
const char *sqlite3ErrStr(int rc){

  sqlite3_mutex_enter(db->mutex);
  pRet = db->pPreUpdateArg;
  db->xPreUpdateCallback = xCallback;
  db->pPreUpdateArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
}

/*
** Register a callback to be invoked each time a transaction or savepoint
** is opened, committed or rolled back.
*/
void *sqlite3_transaction_hook(
  sqlite3 *db,                              /* Database handle */
  void(*xCallback)(void *, int, int),       /* Callback function */
  void *pArg                                /* First callback argument */
){
  void *pRet;
  sqlite3_mutex_enter(db->mutex);
  pRet = db->pTransArg;
  db->xTransCallback = xCallback;
  db->pTransArg = pArg;
  sqlite3_mutex_leave(db->mutex);
  return pRet;
}

#ifndef SQLITE_OMIT_WAL
/*
** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
** 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()).

** documentation for additional information about the meaning and use of
** each of these values.
*/
#define SQLITE_CHECKPOINT_PASSIVE 0
#define SQLITE_CHECKPOINT_FULL    1
#define SQLITE_CHECKPOINT_RESTART 2


/*
** CAPI3REF: The pre-update hook.
** 
** The preupdate_old() API may only be used from within an SQLITE_UPDATE or
** SQLITE_DELETE pre-update callback. The preupdate_modified() API may only 
** be used from within an SQLITE_UPDATE pre-update callback.
*/
SQLITE_EXPERIMENTAL void *sqlite3_preupdate_hook(
  sqlite3 *db,
  void(*xPreUpdate)(
    void *pCtx,                   /* Copy of third arg to preupdate_hook() */
    sqlite3 *db,                  /* Database handle */
    int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
    char const *zDb,              /* Database name */
    char const *zName,            /* Table name */
    sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
    sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
  ),
  void*
);
SQLITE_EXPERIMENTAL int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
SQLITE_EXPERIMENTAL int sqlite3_preupdate_modified(sqlite3 *, int, int *);
SQLITE_EXPERIMENTAL int sqlite3_preupdate_count(sqlite3 *);

/*



** CAPI3REF: The transaction hook.
*/
SQLITE_EXPERIMENTAL
void *sqlite3_transaction_hook(sqlite3 *, void(*)(void *, int, int), void *);

#define SQLITE_BEGIN    1
#define SQLITE_COMMIT   2
#define SQLITE_ROLLBACK 3


/*
** Undo the hack that converts floating point types to integer for
** builds on processors without floating point support.
*/
#ifdef SQLITE_OMIT_FLOATING_POINT

  void *pUpdateArg;
  void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);
  void *pPreUpdateArg;          /* First argument to xPreUpdateCallback */
  void (*xPreUpdateCallback)(   /* Registered using sqlite3_preupdate_hook() */
    void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64
  );
  PreUpdate *pPreUpdate;        /* Context for active pre-update callback */
  void *pTransArg;              /* First argument to xTransCallback */
  void (*xTransCallback)(void*,int,int);
  int iOpenTrans;               /* Open transaction (xTransCallback) plus 1 */
#ifndef SQLITE_OMIT_WAL
  int (*xWalCallback)(void *, sqlite3 *, const char *, int);
  void *pWalArg;
#endif
  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
  void *pCollNeededArg;

void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
Vdbe *sqlite3GetVdbe(Parse*);
void sqlite3PrngSaveState(void);
void sqlite3PrngRestoreState(void);
void sqlite3PrngResetState(void);
void sqlite3RollbackAll(sqlite3*);
void sqlite3TransactionHook(sqlite3 *, int, int);
void sqlite3CodeVerifySchema(Parse*, int);
void sqlite3BeginTransaction(Parse*, int);
void sqlite3CommitTransaction(Parse*);
void sqlite3RollbackTransaction(Parse*);
void sqlite3Savepoint(Parse*, int, Token*);
void sqlite3CloseSavepoints(sqlite3 *);
int sqlite3ExprIsConstant(Expr*);

  char *zAuth;               /* The authorization callback routine */
  int disableAuth;           /* Disable the authorizer if it exists */
  char *zNull;               /* Text to substitute for an SQL NULL value */
  SqlFunc *pFunc;            /* List of SQL functions */
  Tcl_Obj *pUpdateHook;      /* Update hook script (if any) */
  Tcl_Obj *pPreUpdateHook;   /* Pre-update hook script (if any) */
  Tcl_Obj *pRollbackHook;    /* Rollback hook script (if any) */
  Tcl_Obj *pTransHook;       /* Transaction 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() */
  Tcl_Obj *pCollateNeeded;   /* Collation needed script */
  SqlPreparedStmt *stmtList; /* List of prepared statements*/
  SqlPreparedStmt *stmtLast; /* Last statement in the list */

static void DbRollbackHandler(void *clientData){
  SqliteDb *pDb = (SqliteDb*)clientData;
  assert(pDb->pRollbackHook);
  if( TCL_OK!=Tcl_EvalObjEx(pDb->interp, pDb->pRollbackHook, 0) ){
    Tcl_BackgroundError(pDb->interp);
  }
}

/*
** sqlite3_transaction_hook() callback.
*/
static void DbTransHandler(void *clientData, int op, int iLevel){
  static const char *azStr[] = { "BEGIN", "COMMIT", "ROLLBACK" };
  SqliteDb *pDb = (SqliteDb*)clientData;
  Tcl_Interp *interp = pDb->interp;
  Tcl_Obj *pScript;

  assert(pDb->pTransHook);
  assert( SQLITE_BEGIN==1 );
  assert( SQLITE_COMMIT==2 );
  assert( SQLITE_ROLLBACK==3 );

  pScript = Tcl_DuplicateObj(pDb->pTransHook);
  Tcl_IncrRefCount(pScript);
  Tcl_ListObjAppendElement(interp, pScript, Tcl_NewStringObj(azStr[op-1], -1));
  Tcl_ListObjAppendElement(interp, pScript, Tcl_NewIntObj(iLevel));
  if( TCL_OK!=Tcl_EvalObjEx(interp, pScript, 0) ){
    Tcl_BackgroundError(interp);
  }
  Tcl_DecrRefCount(pScript);
}

/*
** This procedure handles wal_hook callbacks.
*/
static int DbWalHandler(
  void *clientData, 
  sqlite3 *db, 

    }
  }

  sqlite3_preupdate_hook(db, (pDb->pPreUpdateHook?DbPreUpdateHandler:0), pDb);
  sqlite3_update_hook(db, (pDb->pUpdateHook?DbUpdateHandler:0), pDb);
  sqlite3_rollback_hook(db, (pDb->pRollbackHook?DbRollbackHandler:0), pDb);
  sqlite3_wal_hook(db, (pDb->pWalHook?DbWalHandler:0), pDb);
  sqlite3_transaction_hook(db, (pDb->pTransHook?DbTransHandler:0), pDb);
}

/*
** The "sqlite" command below creates a new Tcl command for each
** connection it opens to an SQLite database.  This routine is invoked
** whenever one of those connection-specific commands is executed
** in Tcl.  For example, if you run Tcl code like this:

    "errorcode",          "eval",              "exists",
    "function",           "incrblob",          "interrupt",
    "last_insert_rowid",  "nullvalue",         "onecolumn",
    "preupdate",
    "profile",            "progress",          "rekey",
    "restore",            "rollback_hook",     "status",
    "timeout",            "total_changes",     "trace",
    "transaction",        "transaction_hook",
    "unlock_notify",     "update_hook",
    "version",            "wal_hook",          0
  };
  enum DB_enum {
    DB_AUTHORIZER,        DB_BACKUP,           DB_BUSY,
    DB_CACHE,             DB_CHANGES,          DB_CLOSE,
    DB_COLLATE,           DB_COLLATION_NEEDED, DB_COMMIT_HOOK,
    DB_COMPLETE,          DB_COPY,             DB_ENABLE_LOAD_EXTENSION,
    DB_ERRORCODE,         DB_EVAL,             DB_EXISTS,
    DB_FUNCTION,          DB_INCRBLOB,         DB_INTERRUPT,
    DB_LAST_INSERT_ROWID, DB_NULLVALUE,        DB_ONECOLUMN,
    DB_PREUPDATE,
    DB_PROFILE,           DB_PROGRESS,         DB_REKEY,
    DB_RESTORE,           DB_ROLLBACK_HOOK,    DB_STATUS,
    DB_TIMEOUT,           DB_TOTAL_CHANGES,    DB_TRACE,
    DB_TRANSACTION,       DB_TRANSACTION_HOOK,
    DB_UNLOCK_NOTIFY,     DB_UPDATE_HOOK,
    DB_VERSION,           DB_WAL_HOOK
  };
  /* don't leave trailing commas on DB_enum, it confuses the AIX xlc compiler */

  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUBCOMMAND ...");
    return TCL_ERROR;

    break;
  }

  /*
  **    $db wal_hook ?script?
  **    $db update_hook ?script?
  **    $db rollback_hook ?script?
  **    $db transaction_hook ?script?
  */
  case DB_WAL_HOOK: 
  case DB_UPDATE_HOOK: 
  case DB_ROLLBACK_HOOK:
  case DB_TRANSACTION_HOOK: {
    sqlite3 *db = pDb->db;

    /* set ppHook to point at pUpdateHook or pRollbackHook, depending on 
    ** whether [$db update_hook] or [$db rollback_hook] was invoked.
    */
    Tcl_Obj **ppHook; 
    if( choice==DB_WAL_HOOK ) ppHook = &pDb->pWalHook;
    if( choice==DB_UPDATE_HOOK ) ppHook = &pDb->pUpdateHook;
    if( choice==DB_ROLLBACK_HOOK ) ppHook = &pDb->pRollbackHook;
    if( choice==DB_TRANSACTION_HOOK ) ppHook = &pDb->pTransHook;
    if( objc>3 ){
       Tcl_WrongNumArgs(interp, 2, objv, "?SCRIPT?");
       return TCL_ERROR;
    }

    DbHookCmd(interp, pDb, (objc==3 ? objv[2] : 0), ppHook);
    break;

        ** "transaction savepoint". */
        if( db->autoCommit ){
          db->autoCommit = 0;
          db->isTransactionSavepoint = 1;
        }else{
          db->nSavepoint++;
        }

        sqlite3TransactionHook(db, SQLITE_BEGIN, db->nSavepoint);
    
        /* Link the new savepoint into the database handle's list. */
        pNew->pNext = db->pSavepoint;
        db->pSavepoint = pNew;
        pNew->nDeferredCons = db->nDeferredCons;
      }
    }

          }
        }
        if( p1==SAVEPOINT_ROLLBACK && (db->flags&SQLITE_InternChanges)!=0 ){
          sqlite3ExpirePreparedStatements(db);
          sqlite3ResetInternalSchema(db, 0);
          db->flags = (db->flags | SQLITE_InternChanges);
        }

        assert( SAVEPOINT_ROLLBACK+1==SQLITE_ROLLBACK );
        assert( SAVEPOINT_RELEASE+1==SQLITE_COMMIT );
        sqlite3TransactionHook(db, p1+1, iSavepoint+1);
        if( p1==SAVEPOINT_ROLLBACK ){
          sqlite3TransactionHook(db, SQLITE_BEGIN, iSavepoint+1);
        }
      }
  
      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all 
      ** savepoints nested inside of the savepoint being operated on. */
      while( db->pSavepoint!=pSavepoint ){
        pTmp = db->pSavepoint;
        db->pSavepoint = pTmp->pNext;

    if( iRollback ){
      assert( desiredAutoCommit==1 );
      sqlite3RollbackAll(db);
      db->autoCommit = 1;
    }else if( (rc = sqlite3VdbeCheckFk(p, 1))!=SQLITE_OK ){
      goto vdbe_return;
    }else{
      if( desiredAutoCommit==0 ){
        sqlite3TransactionHook(db, SQLITE_BEGIN, 0);
      }
      db->autoCommit = (u8)desiredAutoCommit;
      if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
        p->pc = pc;
        db->autoCommit = (u8)(1-desiredAutoCommit);
        p->rc = rc = SQLITE_BUSY;
        goto vdbe_return;
      }

      assert( sqlite3BtreeIsInTrans(pBt) );
      if( p->iStatement==0 ){
        assert( db->nStatement>=0 && db->nSavepoint>=0 );
        db->nStatement++; 
        p->iStatement = db->nSavepoint + db->nStatement;
      }
      rc = sqlite3BtreeBeginStmt(pBt, p->iStatement);
      sqlite3TransactionHook(db, SQLITE_BEGIN, p->iStatement);

      /* Store the current value of the database handles deferred constraint
      ** counter. If the statement transaction needs to be rolled back,
      ** the value of this counter needs to be restored too.  */
      p->nStmtDefCons = db->nDeferredCons;
    }
  }

#ifndef SQLITE_OMIT_TRACE
    if( db->xProfile && !db->init.busy ){
      sqlite3OsCurrentTimeInt64(db->pVfs, &p->startTime);
    }
#endif

    db->activeVdbeCnt++;
    if( p->readOnly==0 ){ 
      /* If this statement will open an implicit transaction, invoke the
      ** transaction-hook here. */
      if( db->autoCommit && db->writeVdbeCnt==0 ){
        assert( db->nSavepoint==0 );
        sqlite3TransactionHook(db, SQLITE_BEGIN, 0);
      }
      db->writeVdbeCnt++;
    }
    p->pc = 0;
  }
#ifndef SQLITE_OMIT_EXPLAIN
  if( p->explain ){
    rc = sqlite3VdbeList(p);
  }else
#endif /* SQLITE_OMIT_EXPLAIN */

    }
    sqlite3EndBenignMalloc();
    enable_simulated_io_errors();

    sqlite3VtabCommit(db);
  }
#endif

  /* If a transaction-hook is configured, invoke it now to report on the
  ** successful commit operation. */
  if( rc==SQLITE_OK ){
    sqlite3TransactionHook(db, SQLITE_COMMIT, 0);
  }

  return rc;
}

/* 
** This routine checks that the sqlite3.activeVdbeCnt count variable
** matches the number of vdbe's in the list sqlite3.pVdbe that are

        }
        if( rc==SQLITE_OK ){
          rc = rc2;
        }
      }
    }
    db->nStatement--;
    assert( SAVEPOINT_ROLLBACK+1==SQLITE_ROLLBACK );
    assert( SAVEPOINT_RELEASE+1==SQLITE_COMMIT );
    sqlite3TransactionHook(db, eOp+1, p->iStatement);
    p->iStatement = 0;

    /* If the statement transaction is being rolled back, also restore the 
    ** database handles deferred constraint counter to the value it had when 
    ** the statement transaction was opened.  */
    if( eOp==SAVEPOINT_ROLLBACK ){
      db->nDeferredCons = p->nStmtDefCons;

do_execsql_test 7.5.2.0 {
  CREATE TABLE t8(a, b);
  INSERT INTO t8 VALUES('one', 'two');
  INSERT INTO t8 VALUES('three', 'four');
  ALTER TABLE t8 ADD COLUMN c DEFAULT 'xxx';
}

# At time of writing, these two are broken. They demonstraight that the
# sqlite3_preupdate_old() method does not handle the case where ALTER TABLE
# has been used to add a column with a default value other than NULL.
#
do_preupdate_test 7.5.2.1 {
  DELETE FROM t8 WHERE a = 'one'
} {
  DELETE main t8 1 1   one two xxx
}

do_preupdate_test 7.5.2.2 {
  UPDATE t8 SET b = 'five'
} {
  UPDATE main t8 2 2   three four xxx
}

#----------------------------------------------------------------------------
# The following tests - hook-8.* - test the transaction hook.
#
db close
forcedelete test.db
sqlite3 db test.db

proc transaction_hook {op iLevel} {
  lappend ::transaction_hook $op $iLevel
}
db transaction_hook transaction_hook

proc do_transaction_test {tn sql x} {
  set X [list]
  foreach elem $x {lappend X $elem}

  uplevel do_test $tn [list "
    set ::transaction_hook \[list\]
    catchsql { $sql }
    set ::transaction_hook
  "] [list $X]
}

do_transaction_test 8.1.1 "CREATE TABLE t1(x)" {BEGIN 0 COMMIT 0}
do_transaction_test 8.1.2 "BEGIN"              {BEGIN 0}
do_transaction_test 8.1.3 "COMMIT"             {COMMIT 0}
do_transaction_test 8.1.4 "BEGIN ; ROLLBACK"   {BEGIN 0 ROLLBACK 0}

do_execsql_test 8.2.0 {
  CREATE TABLE t2(a PRIMARY KEY, b);
  INSERT INTO t2 VALUES(1, 'one');
  INSERT INTO t2 VALUES(2, 'two');
  INSERT INTO t2 VALUES(3, 'three');
}
do_transaction_test 8.2.1 {
  INSERT INTO t2 VALUES(2, 'xxx')
} {BEGIN 0 ROLLBACK 0}

do_transaction_test 8.2.2 {
  BEGIN; INSERT INTO t2 SELECT a-2, b FROM t2;
} {BEGIN 0 BEGIN 1 ROLLBACK 1}

do_transaction_test 8.2.3 {
  INSERT OR ROLLBACK INTO t2 SELECT a-2, b FROM t2;
} {ROLLBACK 0}

do_transaction_test 8.2.4 {
  BEGIN; INSERT INTO t2 SELECT a+3, b FROM t2;
} {BEGIN 0 BEGIN 1 COMMIT 1}

do_transaction_test 8.2.5 "COMMIT" {COMMIT 0}

do_transaction_test 8.3.1 {SELECT * FROM t2} {}

do_transaction_test 8.4.1 {
  SAVEPOINT top;
  RELEASE top;
} {BEGIN 0 COMMIT 0}

do_transaction_test 8.4.2 {
  SAVEPOINT top;
  ROLLBACK TO top;
  RELEASE top;
} {BEGIN 0 ROLLBACK 0 BEGIN 0 COMMIT 0}

do_transaction_test 8.4.3 {
  SAVEPOINT zero;
    SAVEPOINT one;
      SAVEPOINT two;
        SAVEPOINT three;
  ROLLBACK TO zero;
    SAVEPOINT one;
      SAVEPOINT two;
        SAVEPOINT three;
    ROLLBACK TO one;
      SAVEPOINT two;
  RELEASE zero;

  SAVEPOINT zero;
    SAVEPOINT one;
      SAVEPOINT two;
      RELEASE two;
      SAVEPOINT two;
        SAVEPOINT three;
    RELEASE one;
  ROLLBACK TO zero;
  RELEASE zero;
} {
  BEGIN 0 BEGIN 1 BEGIN 2 BEGIN 3 ROLLBACK 0 BEGIN 0 
  BEGIN 1 BEGIN 2 BEGIN 3 ROLLBACK 1 BEGIN 1 BEGIN 2 
  COMMIT 0

  BEGIN 0 BEGIN 1 BEGIN 2 COMMIT 2 BEGIN 2 BEGIN 3 COMMIT 1 
  ROLLBACK 0 BEGIN 0 COMMIT 0
}

do_transaction_test 8.4.4 {
  BEGIN;
    SAVEPOINT zero;
      SAVEPOINT one;
        SAVEPOINT two;
          SAVEPOINT three;
    ROLLBACK TO zero;
      SAVEPOINT one;
        SAVEPOINT two;
          SAVEPOINT three;
      ROLLBACK TO one;
        SAVEPOINT two;
    RELEASE zero;
  
    SAVEPOINT zero;
      SAVEPOINT one;
        SAVEPOINT two;
        RELEASE two;
        SAVEPOINT two;
          SAVEPOINT three;
      RELEASE one;
    ROLLBACK TO zero;
    RELEASE zero;
  COMMIT;
} {
  BEGIN 0
  BEGIN 1 BEGIN 2 BEGIN 3 BEGIN 4 ROLLBACK 1 BEGIN 1 
  BEGIN 2 BEGIN 3 BEGIN 4 ROLLBACK 2 BEGIN 2 BEGIN 3 
  COMMIT 1

  BEGIN 1 BEGIN 2 BEGIN 3 COMMIT 3 BEGIN 3 BEGIN 4 COMMIT 2 
  ROLLBACK 1 BEGIN 1 COMMIT 1
  COMMIT 0
}

finish_test

  set v [catch {sqlite3 bogus} msg]
  regsub {really_sqlite3} $msg {sqlite3} msg
  lappend v $msg
} [list 1 "wrong # args: should be \"$r\""]
do_test tcl-1.2 {
  set v [catch {db bogus} msg]
  lappend v $msg
} {1 {bad option "bogus": must be authorizer, backup, busy, cache, changes, close, collate, collation_needed, commit_hook, complete, copy, enable_load_extension, errorcode, eval, exists, function, incrblob, interrupt, last_insert_rowid, nullvalue, onecolumn, preupdate, profile, progress, rekey, restore, rollback_hook, status, timeout, total_changes, trace, transaction, transaction_hook, unlock_notify, update_hook, version, or wal_hook}}
do_test tcl-1.2.1 {
  set v [catch {db cache bogus} msg]
  lappend v $msg
} {1 {bad option "bogus": must be flush or size}}
do_test tcl-1.2.2 {
  set v [catch {db cache} msg]
  lappend v $msg