SQLite

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.550 2008/12/18 15:45:07 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

    }
#endif
  }


trans_begun:
  if( rc==SQLITE_OK && wrflag ){
    /* This call makes sure that the pager has the correct number of
    ** open savepoints. If the second parameter is greater than 0 and
    ** the sub-journal is not already open, then it will be opened here.
    */
    rc = sqlite3PagerOpenSavepoint(pBt->pPager, p->db->nSavepoint);
  }

  btreeIntegrity(p);
  sqlite3BtreeLeave(p);
  return rc;
}

#ifndef SQLITE_OMIT_AUTOVACUUM

      rc = SQLITE_OK;
    }else{
      /* At the pager level, a statement transaction is a savepoint with
      ** an index greater than all savepoints created explicitly using
      ** SQL statements. It is illegal to open, release or rollback any
      ** such savepoints while the statement transaction savepoint is active.
      */

      rc = sqlite3PagerOpenSavepoint(pBt->pPager, p->db->nSavepoint+1);
    }
    pBt->inStmt = 1;
  }
  sqlite3BtreeLeave(p);
  return rc;
}

  sqlite3BtreeLeave(p);
  return rc;
}

/*
** The second argument to this function, op, is always SAVEPOINT_ROLLBACK
** or SAVEPOINT_RELEASE. This function either releases or rolls back the
** savepoint identified by parameter iSavepoint, depending on the value 
** of op.
**
** Normally, iSavepoint is greater than or equal to zero. However, if op is
** SAVEPOINT_ROLLBACK, then iSavepoint may also be -1. In this case the 
** contents of the entire transaction are rolled back. This is different
** from a normal transaction rollback, as no locks are released and the
** transaction remains open.
*/
int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
  int rc = SQLITE_OK;
  if( p && p->inTrans==TRANS_WRITE ){
    BtShared *pBt = p->pBt;
    assert( pBt->inStmt==0 );
    assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.516 2008/12/18 15:45:07 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/

    u32 nJRec;         /* Number of Journal Records */
    u32 dummy;
    rc = readJournalHdr(pPager, szJ, &nJRec, &dummy);
    assert( rc!=SQLITE_DONE );
    if( nJRec==0 ){
      nJRec = (szJ - pPager->journalOff) / (pPager->pageSize+8);
    }
    for(ii=0; rc==SQLITE_OK && ii<nJRec && pPager->journalOff<szJ; ii++){
      rc = pager_playback_one_page(pPager, 1, pPager->journalOff, pDone);
      assert( rc!=SQLITE_DONE );
    }
  }
  assert( rc!=SQLITE_OK || pPager->journalOff==szJ );

  /* Now roll back pages from the sub-journal. */

    ** than Pager.dbSize, this means sqlite3PagerTruncate() was called to
    ** make the file smaller (presumably by auto-vacuum code). Do not write
    ** any such pages to the file.
    */
    if( pList->pgno<=pPager->dbSize && 0==(pList->flags&PGHDR_DONT_WRITE) ){
      i64 offset = (pList->pgno-1)*(i64)pPager->pageSize;
      char *pData = CODEC2(pPager, pList->pData, pList->pgno, 6);

      PAGERTRACE4("STORE %d page %d hash(%08x)\n",
                   PAGERID(pPager), pList->pgno, pager_pagehash(pList));
      IOTRACE(("PGOUT %p %d\n", pPager, pList->pgno));
      rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize, offset);
      PAGER_INCR(sqlite3_pager_writedb_count);
      PAGER_INCR(pPager->nWrite);
      if( pList->pgno==1 ){

  PgHdr *pPgHdr;
  u32 change_counter;
  int rc = SQLITE_OK;

#ifndef SQLITE_ENABLE_ATOMIC_WRITE
  assert( isDirect==0 );  /* isDirect is only true for atomic writes */
#endif
  if( !pPager->changeCountDone && pPager->dbSize>0 ){
    /* Open page 1 of the file for writing. */
    rc = sqlite3PagerGet(pPager, 1, &pPgHdr);
    if( rc!=SQLITE_OK ) return rc;

    if( !isDirect ){
      rc = sqlite3PagerWrite(pPgHdr);
      if( rc!=SQLITE_OK ){

/*
** Ensure that there are at least nSavepoint savepoints open.
*/
int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
  int rc = SQLITE_OK;

  if( nSavepoint>pPager->nSavepoint && pPager->useJournal ){
    int ii;

    /* Either the sub-journal is open or there are no active savepoints. */
    assert( pPager->nSavepoint==0 || pPager->sjfd->pMethods );

    /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
    ** if the allocation fails. Otherwise, zero the new portion in case a 

    );
    pPager->aSavepoint = aNew;
    ii = pPager->nSavepoint;
    pPager->nSavepoint = nSavepoint;

    /* Populate the PagerSavepoint structures just allocated. */
    for(/* no-op */; ii<nSavepoint; ii++){
      assert( pPager->dbSizeValid );
      aNew[ii].nOrig = pPager->dbSize;
      aNew[ii].iOffset = (pPager->journalOpen ? pPager->journalOff : 0);
      aNew[ii].iSubRec = pPager->stmtNRec;
      aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
      if( !aNew[ii].pInSavepoint ){
        return SQLITE_NOMEM;
      }

# 2008 December 15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# $Id: savepoint2.test,v 1.1 2008/12/18 15:45:07 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Tests in this file are quite similar to those run by trans.test and
# avtrans.test.
#

proc signature {} {
  return [db eval {SELECT count(*), md5sum(x) FROM t3}]
}



do_test savepoint2-1 {
  execsql {
    PRAGMA cache_size=10;
  }
  db close
  sqlite3 db test.db
  execsql {
    BEGIN;
    CREATE TABLE t3(x TEXT);
    INSERT INTO t3 VALUES(randstr(10,400));
    INSERT INTO t3 VALUES(randstr(10,400));
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    INSERT INTO t3 SELECT randstr(10,400) FROM t3;
    COMMIT;
    SELECT count(*) FROM t3;
  }
} {1024}

unset -nocomplain ::sig
unset -nocomplain SQL

set iterations 20

set SQL(1) {
  DELETE FROM t3 WHERE random()%10!=0;
  INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
  INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
}
set SQL(2) {
  DELETE FROM t3 WHERE random()%10!=0;
  INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
  DELETE FROM t3 WHERE random()%10!=0;
  INSERT INTO t3 SELECT randstr(10,10)||x FROM t3;
} 
set SQL(3) {
  UPDATE t3 SET x = randstr(10, 400) WHERE random()%10;
  INSERT INTO t3 SELECT x FROM t3 WHERE random()%10;
  DELETE FROM t3 WHERE random()%10;
}
set SQL(4) {
  INSERT INTO t3 SELECT randstr(10,400) FROM t3 WHERE (random()%10 == 0);
}



for {set ii 2} {$ii < ($iterations+2)} {incr ii} {

  # Record the database signature. Optionally (every second run) open a
  # transaction. In all cases open savepoint "one", which may or may
  # not be a transaction savepoint, depending on whether or not a real
  # transaction has been opened.
  #
  do_test savepoint2-$ii.1 {
    if {$ii % 2} { execsql BEGIN }
    set ::sig(one) [signature]
    execsql "SAVEPOINT one"
  } {}

  # Execute some SQL on the database. Then rollback to savepoint "one".
  # Check that the database signature is as it was when "one" was opened.
  # 
  do_test savepoint2-$ii.2 {
    execsql $SQL(1)
    execsql "ROLLBACK to one"
    signature
  } $::sig(one)
  integrity_check savepoint2-$ii.2.1

  # Execute some SQL. Then open savepoint "two". Savepoint "two" is therefore
  # nested in savepoint "one".
  #
  do_test savepoint2-$ii.3 {
    execsql $SQL(1)
    set ::sig(two) [signature]
    execsql "SAVEPOINT two"
  } {}

  # More SQL changes. The rollback to savepoint "two". Check that the 
  # signature is as it was when savepoint "two" was opened.
  #
  do_test savepoint2-$ii.4 {
    execsql $SQL(2)
    execsql "ROLLBACK to two"
    signature
  } $::sig(two)
  integrity_check savepoint2-$ii.4.1

  # More SQL changes. The rollback to savepoint "two". Check that the 
  # signature is as it was when savepoint "two" was opened.
  #
  do_test savepoint2-$ii.5 {
    execsql $SQL(2)
    execsql "SAVEPOINT three"
    execsql $SQL(3)
    execsql "RELEASE three"
    execsql "ROLLBACK to one"
    signature
  } $::sig(one)

  # By this point the database is in the same state as it was at the 
  # top of the for{} loop (everything having been rolled back by the 
  # "ROLLBACK TO one" command above). So make a few changes to the 
  # database and COMMIT the open transaction, so that the next iteration
  # of the for{} loop works on a different dataset.
  # 
  # The transaction being committed here may have been opened normally using
  # "BEGIN", or may have been opened using a transaction savepoint created
  # by the "SAVEPOINT one" statement.
  #
  do_test savepoint2-$ii.6 {
    execsql $SQL(4)
    execsql COMMIT
    sqlite3_get_autocommit db
  } {1}
  integrity_check savepoint2-$ii.6.1
}

unset -nocomplain ::sig
unset -nocomplain SQL

finish_test