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 1.310 2006/01/24 14:21:24 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

** with root-page iRoot. Usually, this is called just before cursor
** pExcept is used to modify the table (BtreeDelete() or BtreeInsert()).
*/
static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
  BtCursor *p;
  if( sqlite3ThreadDataReadOnly()->useSharedData ){
    for(p=pBt->pCursor; p; p=p->pNext){
      if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) && 
          p->eState==CURSOR_VALID ){
        int rc = saveCursorPosition(p);
        if( SQLITE_OK!=rc ){
          return rc;
        }
      }
    }
  }

** are no active cursors, it also releases the read lock.
*/
int sqlite3BtreeRollback(Btree *p){
  int rc = SQLITE_OK;
  BtShared *pBt = p->pBt;
  MemPage *pPage1;

  rc = saveAllCursors(pBt, 0, 0);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  btreeIntegrity(p);
  unlockAllTables(p);

  if( p->inTrans==TRANS_WRITE ){
    assert( TRANS_WRITE==pBt->inTransaction );

    rc = sqlite3pager_rollback(pBt->pPager);

# 2005 January 19
#
# 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: shared2.test,v 1.3 2006/01/24 14:21:24 danielk1977 Exp $

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

ifcapable !shared_cache {
  finish_test

        DELETE FROM numbers;
      } db1
    }
  }
  list $a $count
} {32 64}

# Rollback data into or out of a table while a read-uncommitted 
# cursor is scanning it.
#
do_test shared2-2.1 {
  execsql {
    INSERT INTO numbers VALUES(1, 'Medium length text field');
    INSERT INTO numbers VALUES(2, 'Medium length text field');
    INSERT INTO numbers VALUES(3, 'Medium length text field');
    INSERT INTO numbers VALUES(4, 'Medium length text field');
    BEGIN;
    DELETE FROM numbers WHERE (a%2)=0;
  } db1
  set res [list]
  db2 eval {
    SELECT a FROM numbers ORDER BY a;
  } {
    lappend res $a
    if {$a==3} {
      execsql {ROLLBACK} db1
    }
  }
  set res
} {1 3 4}
do_test shared2-2.2 {
  execsql {
    BEGIN;
    INSERT INTO numbers VALUES(5, 'Medium length text field');
    INSERT INTO numbers VALUES(6, 'Medium length text field');
  } db1
  set res [list]
  db2 eval {
    SELECT a FROM numbers ORDER BY a;
  } {
    lappend res $a
    if {$a==5} {
      execsql {ROLLBACK} db1
    }
  }
  set res
} {1 2 3 4 5}

db1 close
db2 close

do_test shared2-3.2 {
  sqlite3_thread_cleanup
  sqlite3_enable_shared_cache 1
} {0}

sqlite3_enable_shared_cache $::enable_shared_cache
finish_test