SQLite

** 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 1.364 2007/08/21 14:27:02 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*

** on success or an error code is something goes wrong.
*/
static int write32bits(sqlite3_file *fd, i64 offset, u32 val){
  char ac[4];
  put32bits(ac, val);
  return sqlite3OsWrite(fd, ac, 4, offset);
}

/*
** If file pFd is open, call sqlite3OsUnlock() on it.
*/
static int osUnlock(sqlite3_file *pFd, int eLock){
  if( !pFd->pMethods ){
    return SQLITE_OK;
  }
  return sqlite3OsUnlock(pFd, eLock);
}

/*
** This function should be called when an error occurs within the pager
** code. The first argument is a pointer to the pager structure, the
** second the error-code about to be returned by a pager API function. 
** The value returned is a copy of the second argument to this function. 
**

/*
** Unlock the database file.
*/
static void pager_unlock(Pager *pPager){
  if( !pPager->exclusiveMode ){
    if( !MEMDB ){
      osUnlock(pPager->fd, NO_LOCK);
      pPager->dbSize = -1;
      IOTRACE(("UNLOCK %p\n", pPager))
    }
    pPager->state = PAGER_UNLOCK;
    pPager->changeCountDone = 0;
  }
}

    pPager->nRec = 0;
  }else{
    assert( pPager->aInJournal==0 );
    assert( pPager->dirtyCache==0 || pPager->useJournal==0 );
  }

  if( !pPager->exclusiveMode ){
    rc2 = osUnlock(pPager->fd, SHARED_LOCK);
    pPager->state = PAGER_SHARED;
  }else if( pPager->state==PAGER_SYNCED ){
    pPager->state = PAGER_EXCLUSIVE;
  }
  pPager->origDbSize = 0;
  pPager->setMaster = 0;
  pPager->needSync = 0;

/*
** Truncate the main file of the given pager to the number of pages
** indicated. Also truncate the cached representation of the file.
*/
static int pager_truncate(Pager *pPager, int nPage){
  int rc = SQLITE_OK;
  if( pPager->state>=PAGER_EXCLUSIVE && pPager->fd->pMethods ){
    rc = sqlite3OsTruncate(pPager->fd, pPager->pageSize*(i64)nPage);
  }
  if( rc==SQLITE_OK ){
    pPager->dbSize = nPage;
    pager_truncate_cache(pPager);
  }
  return rc;
}

/*
** Set the sectorSize for the given pager.
**
** The sector size is the larger of the sector size reported
** by sqlite3OsSectorSize() and the pageSize.
*/
static void setSectorSize(Pager *pPager){
  assert(pPager->fd->pMethods||pPager->tempFile);
  if( !pPager->tempFile ){
    /* Sector size doesn't matter for temporary files. Also, the file
    ** may not have been opened yet, in whcih case the OsSectorSize()
    ** call will segfault.
    */
    pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
  }
  if( pPager->sectorSize<pPager->pageSize ){
    pPager->sectorSize = pPager->pageSize;
  }
}

/*
** Playback the journal and thus restore the database file to

          int fout = 0;
          rc = sqlite3OsOpen(pVfs, pPager->zFilename, pPager->fd, oflag, &fout);
          readOnly = (fout&SQLITE_OPEN_READONLY);
        }
      }
    }
  }else{
    /* If a temporary file is requested, it is not opened immediately.
    ** In this case we accept the default page size and delay actually
    ** opening the file until the first call to OsWrite().
    */ 
    /* rc = sqlite3PagerOpentemp(pVfs, pPager->fd, pPager->zFilename); */

    tempFile = 1;

    pPager->state = PAGER_EXCLUSIVE;
  }

  if( pPager && rc==SQLITE_OK ){
    pPager->pTmpSpace = (char *)sqlite3_malloc(SQLITE_DEFAULT_PAGE_SIZE);
  }

  /* If an error occured in either of the blocks above, free the memory 

  pPager->noSync = pPager->tempFile || !useJournal;
  pPager->fullSync = (pPager->noSync?0:1);
  pPager->sync_flags = SQLITE_SYNC_NORMAL;
  /* pPager->pFirst = 0; */
  /* pPager->pFirstSynced = 0; */
  /* pPager->pLast = 0; */
  pPager->nExtra = FORCE_ALIGNMENT(nExtra);
  assert(pPager->fd->pMethods||memDb||tempFile);
  if( !memDb ){
    setSectorSize(pPager);
  }
  /* pPager->pBusyHandler = 0; */
  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
  *ppPager = pPager;
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT

** these cases sqlite3OsRead() will return an error, to which the correct 
** response is to zero the memory at pDest and continue.  A real IO error 
** will presumably recur and be picked up later (Todo: Think about this).
*/
int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
  int rc = SQLITE_OK;
  memset(pDest, 0, N);
  assert(MEMDB||pPager->fd->pMethods||pPager->tempFile);
  if( pPager->fd->pMethods ){
    IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
    rc = sqlite3OsRead(pPager->fd, pDest, N, 0);
    if( rc==SQLITE_IOERR_SHORT_READ ){
      rc = SQLITE_OK;
    }
  }
  return rc;
}

/*
** Return the total number of pages in the disk file associated with
** pPager. 
**
** If the PENDING_BYTE lies on the page directly after the end of the
** file, then consider this page part of the file too. For example, if
** PENDING_BYTE is byte 4096 (the first byte of page 5) and the size of the
** file is 4096 bytes, 5 is returned instead of 4.
*/
int sqlite3PagerPagecount(Pager *pPager){
  i64 n = 0;
  int rc;
  assert( pPager!=0 );
  if( pPager->errCode ){
    return 0;
  }
  if( pPager->dbSize>=0 ){
    n = pPager->dbSize;
  } else {
    assert(pPager->fd->pMethods||pPager->tempFile);
    if( (pPager->fd->pMethods)
     && (rc = sqlite3OsFileSize(pPager->fd, &n))!=SQLITE_OK ){
      pager_error(pPager, rc);
      return 0;
    }
    if( n>0 && n<pPager->pageSize ){
      n = 1;
    }else{
      n /= pPager->pageSize;

  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  pList = sort_pagelist(pList);
  while( pList ){

    /* If the file has not yet been opened, open it now. */
    if( !pPager->fd->pMethods ){
      assert(pPager->tempFile);
      rc = sqlite3PagerOpentemp(pPager->pVfs, pPager->fd, pPager->zFilename);
      if( rc ) return rc;
    }

    assert( pList->dirty );
    /* If there are dirty pages in the page cache with page numbers greater
    ** 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 ){

/*
** Read the content of page pPg out of the database file.
*/
static int readDbPage(Pager *pPager, PgHdr *pPg, Pgno pgno){
  int rc;
  i64 offset;
  assert( MEMDB==0 );
  assert(pPager->fd->pMethods||pPager->tempFile);
  if( !pPager->fd->pMethods ){
    return SQLITE_IOERR_SHORT_READ;
  }
  offset = (pgno-1)*(i64)pPager->pageSize;
  rc = sqlite3OsRead(pPager->fd, PGHDR_TO_DATA(pPg), pPager->pageSize, offset);
  PAGER_INCR(sqlite3_pager_readdb_count);
  PAGER_INCR(pPager->nRead);
  IOTRACE(("PGIN %p %d\n", pPager, pgno));
  if( pgno==1 ){
    memcpy(&pPager->dbFileVers, &((u8*)PGHDR_TO_DATA(pPg))[24],

#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests for the conflict resolution extension
# to SQLite.
#
# $Id: conflict.test,v 1.30 2007/08/21 14:27:02 danielk1977 Exp $

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

ifcapable !conflict {
  finish_test
  return

#   cmd    An UPDATE command to execute against table t1
#   t0     True if there is an error from $cmd
#   t1     Content of "b" column of t1 assuming no error in $cmd
#   t2     Content of "x" column of t3
#   t3     Number of temporary files for tables
#   t4     Number of temporary files for statement journals
#
# Update: Since temporary table files are now opened lazily, and none
# of the following tests use large quantities of data, t3 is always 0.
#
foreach {i conf1 cmd t0 t1 t2 t3 t4} {
  1 {}       UPDATE                  1 {6 7 8 9}  1 0 1
  2 REPLACE  UPDATE                  0 {7 6 9}    1 0 0
  3 IGNORE   UPDATE                  0 {6 7 3 9}  1 0 0
  4 FAIL     UPDATE                  1 {6 7 3 4}  1 0 0
  5 ABORT    UPDATE                  1 {1 2 3 4}  1 0 1
  6 ROLLBACK UPDATE                  1 {1 2 3 4}  0 0 0
  7 REPLACE  {UPDATE OR IGNORE}      0 {6 7 3 9}  1 0 0
  8 IGNORE   {UPDATE OR REPLACE}     0 {7 6 9}    1 0 0
  9 FAIL     {UPDATE OR IGNORE}      0 {6 7 3 9}  1 0 0
 10 ABORT    {UPDATE OR REPLACE}     0 {7 6 9}    1 0 0
 11 ROLLBACK {UPDATE OR IGNORE}      0 {6 7 3 9}  1 0 0
 12 {}       {UPDATE OR IGNORE}      0 {6 7 3 9}  1 0 0
 13 {}       {UPDATE OR REPLACE}     0 {7 6 9}    1 0 0
 14 {}       {UPDATE OR FAIL}        1 {6 7 3 4}  1 0 0
 15 {}       {UPDATE OR ABORT}       1 {1 2 3 4}  1 0 1
 16 {}       {UPDATE OR ROLLBACK}    1 {1 2 3 4}  0 0 0
} {
  if {$t0} {set t1 {column a is not unique}}
  if {[info exists TEMP_STORE] && $TEMP_STORE>=2} {
    set t3 $t4