SQLite: Check-in [8a9f3e66]

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Overview

Comment:	Add asserts to make sure that database connection locks are held when accessing the lookaside memory allocation buffers. No defects were found. (CVS 6374)
Downloads:	Tarball \| ZIP archive \| SQL archive
Timelines:	family \| ancestors \| descendants \| both \| trunk
Files:	files \| file ages \| folders
SHA1:	8a9f3e66069146ad1b1bc2686567882dc87603a9
User & Date:	drh 2009-03-23 17:49:15

Context

2009-03-23
21:37		Clarify the meaning of a comment. No changes to code. (CVS 6375) (check-in: 7c2df04b user: drh tags: trunk)
17:49		Add asserts to make sure that database connection locks are held when accessing the lookaside memory allocation buffers. No defects were found. (CVS 6374) (check-in: 8a9f3e66 user: drh tags: trunk)
17:11		Fix an obscure race condition that can occur when multiple threads, shared cache and DDL statements are combined. Enhance notify2.test to test this scenario. (CVS 6373) (check-in: 92ec5975 user: danielk1977 tags: trunk)

Changes

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Changes to src/malloc.c.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** Memory allocation functions used throughout sqlite.
**
** $Id: malloc.c,v 1.59 2009/03/23 04:33:33 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>

/*
** This routine runs when the memory allocator sees that the
** total memory allocation is about to exceed the soft heap
................................................................................
** Return the size of a memory allocation previously obtained from
** sqlite3Malloc() or sqlite3_malloc().
*/
int sqlite3MallocSize(void *p){
  return sqlite3GlobalConfig.m.xSize(p);
}
int sqlite3DbMallocSize(sqlite3 *db, void *p){

  if( p==0 ){
    return 0;
  }else if( isLookaside(db, p) ){
    return db->lookaside.sz;
  }else{
    return sqlite3GlobalConfig.m.xSize(p);
  }
................................................................................
}

/*
** Free memory that might be associated with a particular database
** connection.
*/
void sqlite3DbFree(sqlite3 *db, void *p){

  if( isLookaside(db, p) ){
    LookasideSlot *pBuf = (LookasideSlot*)p;
    pBuf->pNext = db->lookaside.pFree;
    db->lookaside.pFree = pBuf;
    db->lookaside.nOut--;
  }else{
    sqlite3_free(p);
................................................................................
** that all prior mallocs (ex: "a") worked too.
*/
void *sqlite3DbMallocRaw(sqlite3 *db, int n){
  void *p;
#ifndef SQLITE_OMIT_LOOKASIDE
  if( db ){
    LookasideSlot *pBuf;

    if( db->mallocFailed ){
      return 0;
    }
    if( db->lookaside.bEnabled && n<=db->lookaside.sz
         && (pBuf = db->lookaside.pFree)!=0 ){
      db->lookaside.pFree = pBuf->pNext;
      db->lookaside.nOut++;
................................................................................

/*
** Resize the block of memory pointed to by p to n bytes. If the
** resize fails, set the mallocFailed flag in the connection object.
*/
void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){
  void *pNew = 0;

  if( db->mallocFailed==0 ){
    if( p==0 ){
      return sqlite3DbMallocRaw(db, n);
    }
    if( isLookaside(db, p) ){
      if( n<=db->lookaside.sz ){
        return p;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** Memory allocation functions used throughout sqlite.
**
** $Id: malloc.c,v 1.60 2009/03/23 17:49:15 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>

/*
** This routine runs when the memory allocator sees that the
** total memory allocation is about to exceed the soft heap
................................................................................
** Return the size of a memory allocation previously obtained from
** sqlite3Malloc() or sqlite3_malloc().
*/
int sqlite3MallocSize(void *p){
  return sqlite3GlobalConfig.m.xSize(p);
}
int sqlite3DbMallocSize(sqlite3 *db, void *p){
  assert( db==0 || sqlite3_mutex_held(db->mutex) );
  if( p==0 ){
    return 0;
  }else if( isLookaside(db, p) ){
    return db->lookaside.sz;
  }else{
    return sqlite3GlobalConfig.m.xSize(p);
  }
................................................................................
}

/*
** Free memory that might be associated with a particular database
** connection.
*/
void sqlite3DbFree(sqlite3 *db, void *p){
  assert( db==0 || sqlite3_mutex_held(db->mutex) );
  if( isLookaside(db, p) ){
    LookasideSlot *pBuf = (LookasideSlot*)p;
    pBuf->pNext = db->lookaside.pFree;
    db->lookaside.pFree = pBuf;
    db->lookaside.nOut--;
  }else{
    sqlite3_free(p);
................................................................................
** that all prior mallocs (ex: "a") worked too.
*/
void *sqlite3DbMallocRaw(sqlite3 *db, int n){
  void *p;
#ifndef SQLITE_OMIT_LOOKASIDE
  if( db ){
    LookasideSlot *pBuf;
    assert( sqlite3_mutex_held(db->mutex) );
    if( db->mallocFailed ){
      return 0;
    }
    if( db->lookaside.bEnabled && n<=db->lookaside.sz
         && (pBuf = db->lookaside.pFree)!=0 ){
      db->lookaside.pFree = pBuf->pNext;
      db->lookaside.nOut++;
................................................................................

/*
** Resize the block of memory pointed to by p to n bytes. If the
** resize fails, set the mallocFailed flag in the connection object.
*/
void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){
  void *pNew = 0;
  assert( sqlite3_mutex_held(db->mutex) );
  if( db->mallocFailed==0 ){
    if( p==0 ){
      return sqlite3DbMallocRaw(db, n);
    }
    if( isLookaside(db, p) ){
      if( n<=db->lookaside.sz ){
        return p;