libs-base/Source/NSAutoreleasePool.m

/* Implementation of auto release pool for delayed disposal
   Copyright (C) 1995 Free Software Foundation, Inc.
   
   Written by:  R. Andrew McCallum <mccallum@gnu.ai.mit.edu>
   Date: January 1995
   
   This file is part of the GNU Objective C Class Library.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
   
   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.
   
   You should have received a copy of the GNU Library General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */ 

#include <objects/stdobjects.h>
#include <foundation/NSAutoreleasePool.h>

#include <objects/collhash.h>
#include <objects/eltfuncs.h>
#include <objects/objc-malloc.h>
#include <limits.h>

/* Doesn't handle multi-threaded stuff.
   Doesn't handle exceptions. */

/* Put the stuff from initialize into a runtime init function. 
   This class should be made more efficient, especially:
     [[NSAutorelease alloc] init]
     [current_pool addObject:o] (REALLOC-case)
   */

static NSAutoreleasePool *current_pool = nil;

/* When this is `NO', autoreleased objects are never actually sent a 
   `release' message.  Memory use grows, and grows, and... */
static BOOL autorelease_enabled = YES;

/* When this is `YES', every call to addObject, checks to make sure 
   isn't being set up to release itself too many times. */
static BOOL double_release_check_enabled = NO;

/* When the released_count gets over this value, we call error:.
   In the future, I may change this to raise an exception or call 
   a function instead. */
static unsigned pool_count_warning_threshhold = UINT_MAX;

#define DEFAULT_SIZE 64

@implementation NSAutoreleasePool

/* This method not in OpenStep */
- parentAutoreleasePool
{
  return parent;
}

/* This method not in OpenStep */
- (unsigned) autoreleaseCount
{
  return released_count;
}

/* This method not in OpenStep */
- (unsigned) autoreleaseCountForObject: anObject
{
  unsigned count = 0;
  int i;

  for (i = 0; i < released_count; i++)
    if (released[i] == anObject)
      count++;
  return count;
}

/* This method not in OpenStep */
+ (unsigned) autoreleaseCountForObject: anObject
{
  unsigned count;
  id pool = current_pool;
  while (pool)
    {
      count += [pool autoreleaseCountForObject:anObject];
      pool = [pool parentAutoreleasePool];
    }
  return count;
}

+ currentPool
{
  return current_pool;
}

+ (void) addObject: anObj
{
  [current_pool addObject:anObj];
}

- (void) addObject: anObj
{
  if (!autorelease_enabled)
    return;

  if (double_release_check_enabled)
    {
      unsigned release_count = [[self class] autoreleaseCountForObject:anObj];
      unsigned retain_count = [anObj retainCount];
      if (release_count > retain_count + 1)
	[self error:"Autorelease would release object too many times."];
    }

  if (released_count >= pool_count_warning_threshhold)
    [self error:"AutoreleasePool count threshhold exceeded."];

  released_count++;
  if (released_count == released_size)
    {
      released_size *= 2;
      OBJC_REALLOC(released, id, released_size);
    }
  released[released_count] = anObj;
}

- init
{
  parent = current_pool;
  current_pool = self;
  OBJC_MALLOC(released, id, DEFAULT_SIZE);
  released_size = DEFAULT_SIZE;
  released_count = 0;
  return self;
}

- (id) retain
{
  [self error:"Don't call `-retain' on a NSAutoreleasePool"];
  return self;
}

- (oneway void) release
{
  [self dealloc];
}

- (void) dealloc
{
  int i;

  if (parent)
    current_pool = parent;
  else
    current_pool = [[NSAutoreleasePool alloc] init];
  for (i = 0; i < released_count; i++)
    [released[i] release];
  OBJC_FREE(released);
  NSDeallocateObject(self);
}

- autorelease
{
  [self error:"Don't call `-autorelease' on a NSAutoreleasePool"];
  return self;
}

+ (void) enableRelease: (BOOL)enable
{
  autorelease_enabled = enable;
}

+ (void) enableDoubleReleaseCheck: (BOOL)enable
{
  double_release_check_enabled = enable;
}

+ (void) setPoolCountThreshhold: (unsigned)c
{
  pool_count_warning_threshhold = c;
}

@end