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 1.240 2006/01/16 15:14:28 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

  int tempFile = 0;
  int memDb = 0;
  int readOnly = 0;
  int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
  int noReadlock = (flags & PAGER_NO_READLOCK)!=0;
  char zTemp[SQLITE_TEMPNAME_SIZE];
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  const ThreadData *pTsdro = sqlite3ThreadDataReadOnly();
#endif

  /* If malloc() has already failed return SQLITE_NOMEM. Before even
  ** testing for this, set *ppPager to NULL so the caller knows the pager
  ** structure was never allocated. 
  */
  *ppPager = 0;

  /* pPager->pLast = 0; */
  pPager->nExtra = FORCE_ALIGNMENT(nExtra);
  pPager->sectorSize = PAGER_SECTOR_SIZE;
  /* pPager->pBusyHandler = 0; */
  /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
  *ppPager = pPager;
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  if( pTsdro->useMemoryManagement ){
    ThreadData *pTsd = sqlite3ThreadData();
    pPager->pNext = pTsd->pPager;
    pTsd->pPager = pPager;
  }
#endif
  return SQLITE_OK;
}

/*
** Set the busy handler function.
*/

** is made to roll it back. If an error occurs during the rollback 
** a hot journal may be left in the filesystem but no error is returned
** to the caller.
*/
int sqlite3pager_close(Pager *pPager){
  PgHdr *pPg, *pNext;
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  const ThreadData *pTsd = sqlite3ThreadDataReadOnly();
#endif

  switch( pPager->state ){
    case PAGER_RESERVED:
    case PAGER_SYNCED: 
    case PAGER_EXCLUSIVE: {
      /* We ignore any IO errors that occur during the rollback

  ** }
  */

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  /* Remove the pager from the linked list of pagers starting at 
  ** ThreadData.pPager if memory-management is enabled.
  */
  if( pTsd->useMemoryManagement ){
    if( pPager==pTsd->pPager ){
      pTsd->pPager = pPager->pNext;
    }else{
      Pager *pTmp;
      for(pTmp = pTsd->pPager; pTmp->pNext!=pPager; pTmp=pTmp->pNext);
      pTmp->pNext = pPager->pNext;
    }
  }
#endif

  sqliteFree(pPager);
  return SQLITE_OK;
}

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the printf() interface to SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.191 2006/01/15 02:30:58 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

  int objc,              /* Number of arguments */
  Tcl_Obj *CONST objv[]  /* Command arguments */
){
  extern int sqlite3OutstandingMallocs(Tcl_Interp *interp);

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  if( objc==2 ){
    const ThreadData *pTd = sqlite3ThreadDataReadOnly();
    const char *zArg = Tcl_GetString(objv[1]);
    if( 0==strcmp(zArg, "-bytes") ){
      Tcl_SetObjResult(interp, Tcl_NewIntObj(pTd->nAlloc));
    }else if( 0==strcmp(zArg, "-maxbytes") ){
      Tcl_SetObjResult(interp, Tcl_NewWideIntObj(pTd->nMaxAlloc));
    }else if( 0==strcmp(zArg, "-clearmaxbytes") ){
      pTd->nMaxAlloc = pTd->nAlloc;

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.171 2006/01/15 11:39:18 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <stdarg.h>
#include <ctype.h>

/*

** sqlite3Malloc(), sqlite3Realloc() or sqlite3ReallocOrFree().
**
** The number of bytes allocated does not include any overhead inserted by 
** any malloc() wrapper functions that may be called. So the value returned
** is the number of bytes that were available to SQLite using pointer p, 
** regardless of how much memory was actually allocated.
*/
#if 0          /* This is never actually used */
int sqlite3AllocSize(void *p){
  return OSSIZEOF(p);
}
#endif

/*
** Make a copy of a string in memory obtained from sqliteMalloc(). These 
** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This
** is because when memory debugging is turned on, these two functions are 
** called via macros that record the current file and line number in the
** ThreadData structure.

#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# This file contains test cases focused on the two memory-management APIs, 
# sqlite3_soft_heap_limit() and sqlite3_release_memory().
#
# $Id: malloc5.test,v 1.5 2006/01/09 09:59:49 danielk1977 Exp $

#---------------------------------------------------------------------------
# NOTES ON EXPECTED BEHAVIOUR
#
#---------------------------------------------------------------------------

# Skip these tests if OMIT_MEMORY_MANAGEMENT was defined at compile time.
ifcapable !memorymanage {
   finish_test
   return
}

sqlite3_enable_memory_management 1
sqlite3 db test.db

do_test malloc5-1.1 {
  # Simplest possible test. Call sqlite3_release_memory when there is exactly
  # one unused page in a single pager cache. This test case set's the 
  # value of the ::pgalloc variable, which is used in subsequent tests.
  #

} [list 20000 [expr int(20000.0 * 4999.5)] [expr int(20000.0 * 4999.5)]]

# Restore the soft heap limit.
sqlite3_soft_heap_limit $::soft_limit
finish_test

catch {db close}
sqlite3_enable_memory_management 0