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 1.467 2008/07/22 05:18:01 shane Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*

** SQLITE_OK returned.
*/
static int readMasterJournal(sqlite3_file *pJrnl, char *zMaster, int nMaster){
  int rc;
  u32 len;
  i64 szJ;
  u32 cksum;
  u32 u;                   /* Unsigned loop counter */
  unsigned char aMagic[8]; /* A buffer to hold the magic header */

  zMaster[0] = '\0';

  rc = sqlite3OsFileSize(pJrnl, &szJ);
  if( rc!=SQLITE_OK || szJ<16 ) return rc;

  rc = sqlite3OsRead(pJrnl, zMaster, len, szJ-16-len);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  zMaster[len] = '\0';

  /* See if the checksum matches the master journal name */
  for(u=0; u<len; u++){
    cksum -= zMaster[u];
   }
  if( cksum ){
    /* If the checksum doesn't add up, then one or more of the disk sectors
    ** containing the master journal filename is corrupted. This means
    ** definitely roll back, so just return SQLITE_OK and report a (nul)
    ** master-journal filename.
    */

** If an I/O or malloc() error occurs, the journal-file is not deleted
** and an error code is returned.
*/
static int pager_playback(Pager *pPager, int isHot){
  sqlite3_vfs *pVfs = pPager->pVfs;
  i64 szJ;                 /* Size of the journal file in bytes */
  u32 nRec;                /* Number of Records in the journal */
  u32 u;                   /* Unsigned loop counter */
  Pgno mxPg = 0;           /* Size of the original file in pages */
  int rc;                  /* Result code of a subroutine */
  int res = 1;             /* Value returned by sqlite3OsAccess() */
  char *zMaster = 0;       /* Name of master journal file if any */

  /* Figure out how many records are in the journal.  Abort early if
  ** the journal is empty.

      if( rc!=SQLITE_OK ){
        goto end_playback;
      }
    }

    /* Copy original pages out of the journal and back into the database file.
    */
    for(u=0; u<nRec; u++){
      rc = pager_playback_one_page(pPager, pPager->jfd, pPager->journalOff, 1);
      if( rc!=SQLITE_OK ){
        if( rc==SQLITE_DONE ){
          rc = SQLITE_OK;
          pPager->journalOff = szJ;
          break;
        }else{

**
*************************************************************************
** This file contains code used for creating, destroying, and populating
** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
** to version 2.8.7, all this code was combined into the vdbe.c source file.
** But that file was getting too big so this subroutines were split out.
**
** $Id: vdbeaux.c,v 1.399 2008/07/22 05:18:01 shane Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

  const void *pKey,      /* The binary record */
  void *pSpace,          /* Space available to hold resulting object */
  int szSpace            /* Size of pSpace[] in bytes */
){
  const unsigned char *aKey = (const unsigned char *)pKey;
  UnpackedRecord *p;
  int nByte;
  int idx, d;
  u16 u;                 /* Unsigned loop counter */
  u32 szHdr;
  Mem *pMem;
  
  assert( sizeof(Mem)>sizeof(*p) );
  nByte = sizeof(Mem)*(pKeyInfo->nField+2);
  if( nByte>szSpace ){
    p = sqlite3DbMallocRaw(pKeyInfo->db, nByte);
    if( p==0 ) return 0;
    p->needFree = 1;
  }else{
    p = pSpace;
    p->needFree = 0;
  }
  p->pKeyInfo = pKeyInfo;
  p->nField = pKeyInfo->nField + 1;
  p->needDestroy = 1;
  p->aMem = pMem = &((Mem*)p)[1];
  idx = getVarint32(aKey, szHdr);
  d = szHdr;
  u = 0;
  while( idx<szHdr && u<p->nField ){
    u32 serial_type;

    idx += getVarint32( aKey+idx, serial_type);
    if( d>=nKey && sqlite3VdbeSerialTypeLen(serial_type)>0 ) break;
    pMem->enc = pKeyInfo->enc;
    pMem->db = pKeyInfo->db;
    pMem->flags = 0;
    pMem->zMalloc = 0;
    d += sqlite3VdbeSerialGet(&aKey[d], serial_type, pMem);
    pMem++;
    u++;
  }
  p->nField = u;
  return (void*)p;
}

/*
** This routine destroys a UnpackedRecord object
*/
void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord *p){