Fossil

    int (*xHook)(void);         /* Functions to call at db_end_transaction() */
    int sequence;               /* Call functions in sequence order */
  } aHook[5];
  char *azDeleteOnFail[3];  /* Files to delete on a failure */
  char *azBeforeCommit[5];  /* Commands to run prior to COMMIT */
  int nBeforeCommit;        /* Number of entries in azBeforeCommit */
  int nPriorChanges;        /* sqlite3_total_changes() at transaction start */
  const char *zStartFile;   /* File in which transaction was started */
  int iStartLine;           /* Line of zStartFile where transaction started */
} db = {0, 0, 0, 0, 0, 0, };

/*
** Arrange for the given file to be deleted on a failure.
*/
void db_delete_on_failure(const char *zFilename){
  assert( db.nDeleteOnFail<count(db.azDeleteOnFail) );
  db.azDeleteOnFail[db.nDeleteOnFail++] = fossil_strdup(zFilename);
}

/*
** Return the transaction nesting depth.  0 means we are currently
** not in a transaction.
*/
int db_transaction_nesting_depth(void){
  return db.nBegin;
}

/*
** Return a pointer to a string that is the code point where the
** current transaction was started.
*/
char *db_transaction_start_point(void){
  return mprintf("%s:%d", db.zStartFile, db.iStartLine);
}

/*
** This routine is called by the SQLite commit-hook mechanism
** just prior to each commit.  All this routine does is verify
** that nBegin really is zero.  That insures that transactions
** cannot commit by any means other than by calling db_end_transaction()
** below.
**
** This is just a safety and sanity check.
*/
static int db_verify_at_commit(void *notUsed){
  if( db.nBegin ){
    fossil_panic("illegal commit attempt");
    return 1;
  }
  return 0;
}

/*
** Silently add the filename and line number as parameter to each
** db_begin_transaction call.
*/
#if INTERFACE
#define db_begin_transaction() db_begin_transaction_real(__FILE__,__LINE__)
#endif

/*
** Begin and end a nested transaction
*/
void db_begin_transaction_real(const char *zStartFile, int iStartLine){
  if( db.nBegin==0 ){
    db_multi_exec("BEGIN");
    sqlite3_commit_hook(g.db, db_verify_at_commit, 0);
    db.nPriorChanges = sqlite3_total_changes(g.db);
    db.doRollback = 0;
    db.zStartFile = zStartFile;
    db.iStartLine = iStartLine;
  }
  db.nBegin++;
}
void db_end_transaction(int rollbackFlag){
  if( g.db==0 ) return;
  if( db.nBegin<=0 ){
    fossil_warning("Extra call to db_end_transaction");

}
void db_column_blob(Stmt *pStmt, int N, Blob *pBlob){
  blob_append(pBlob, sqlite3_column_blob(pStmt->pStmt, N),
              sqlite3_column_bytes(pStmt->pStmt, N));
}
Blob db_column_text_as_blob(Stmt *pStmt, int N){
  Blob x;
  blob_init(&x, (char*)sqlite3_column_text(pStmt->pStmt,N),
            sqlite3_column_bytes(pStmt->pStmt,N));
  return x;
}

/*
** Initialize a blob to an ephemeral copy of the content of a
** column in the current row.  The data in the blob will become

    fprintf(stderr, "-- PCACHE_OVFLOW          %10d %10d\n", cur, hiwtr);
    fprintf(stderr, "-- prepared statements    %10d\n", db.nPrepare);
  }
  while( db.pAllStmt ){
    db_finalize(db.pAllStmt);
  }
  if( db.nBegin && reportErrors ){
    fossil_warning("Transaction started at %s:%d never commits",
                   db.zStartFile, db.iStartLine);
    db_end_transaction(1);
  }
  pStmt = 0;
  g.dbIgnoreErrors++; /* Stop "database locked" warnings from PRAGMA optimize */
  sqlite3_exec(g.db, "PRAGMA optimize", 0, 0, 0);
  g.dbIgnoreErrors--;
  db_close_config();

** This routine is called after certain webpages have been run and
** have already responded.
*/
void email_auto_exec(void){
  int iJulianDay;
  if( g.db==0 ) return;
  if( db_transaction_nesting_depth()!=0 ){
    fossil_warning("Called email_auto_exec() from within transaction "
                   "started at %z", db_transaction_start_point());
    return;
  }
  db_begin_transaction();
  if( !email_tables_exist() ) goto autoexec_done;
  if( !db_get_boolean("email-autoexec",0) ) goto autoexec_done;
  email_send_alerts(0);
  iJulianDay = db_int(0, "SELECT julianday('now')");