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tweak NSCache changes

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git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@28582 72102866-910b-0410-8b05-ffd578937521
This commit is contained in:
Richard Frith-MacDonald 2009-09-01 04:40:07 +00:00
parent c00f54bafb
commit 6bbe31c18d
3 changed files with 309 additions and 185 deletions
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15
ChangeLog
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@ -1,5 +1,18 @@
2009-08-31 David Chisnall <csdavec@swan.ac.uk>
2009-09-01 Richard Frith-Macdonald <rfm@gnu.org>
* Headers/Foundation/NSCache.h:
* Source/NSCache.m:
Great additions... tweaked with whitespace changes to conform to
coding standards, addition of copyright headers, addition of standard
prevention of multiple inclusion, include changes to build independant
of any existing installation.
2009-08-31 David Chisnall <csdavec@swan.ac.uk>
* Headers/Foundation/NSCache.h:
* Headers/Foundation/Foundation.h:
* Source/NSCache.m:
* Source/GNUmakefile:
Added NSCache implementation.
2009-08-31 Richard Frith-Macdonald <rfm@gnu.org>

125
Headers/Foundation/NSCache.h
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@ -1,104 +1,152 @@
/* Interface for NSCache for GNUStep
Copyright (C) 2009 Free Software Foundation, Inc.
Written by: David Chisnall <csdavec@swan.ac.uk>
Created: 2009
This file is part of the GNUstep Base Library.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser 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 Lesser General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02111 USA.
*/
#ifndef __NSCache_h_GNUSTEP_BASE_INCLUDE
#define __NSCache_h_GNUSTEP_BASE_INCLUDE
#import <GNUstepBase/GSVersionMacros.h>
#if OS_API_VERSION(MAC_OS_X_VERSION_10_6, GS_API_LATEST)
#import <Foundation/NSObjCRuntime.h>
#import <Foundation/NSObject.h>
#if defined(__cplusplus)
extern "C" {
#endif
@class NSString;
@class NSMutableDictionary;
@class NSMutableArray;
#ifndef __has_feature
#define __has_feature(x) 0
#endif
@interface NSCache : NSObject
{
#if !__has_feature(objc_nonfragile_abi) || defined(EXPOSE_GSCACHE_IVARS)
@private
/** The maximum total cost of all cache objects. */
NSUInteger _costLimit;
/** Total cost of currently-stored objects. */
NSUInteger _totalCost;
/** The maximum number of objects in the cache. */
NSUInteger _countLimit;
/** The delegate object, notified when objects are about to be evicted. */
id _delegate;
/** Flag indicating whether discarded objects should be evicted */
BOOL _evictsObjectsWithDiscardedContent;
/** Name of this cache. */
NSString *_name;
/** The mapping from names to objects in this cache. */
NSMutableDictionary *_objects;
/** LRU ordering of all potentially-evictable objects in this cache. */
NSMutableArray *_accesses;
/** Total number of accesses to objects */
int64_t _totalAccesses;
@private
/** The maximum total cost of all cache objects. */
NSUInteger _costLimit;
/** Total cost of currently-stored objects. */
NSUInteger _totalCost;
/** The maximum number of objects in the cache. */
NSUInteger _countLimit;
/** The delegate object, notified when objects are about to be evicted. */
id _delegate;
/** Flag indicating whether discarded objects should be evicted */
BOOL _evictsObjectsWithDiscardedContent;
/** Name of this cache. */
NSString *_name;
/** The mapping from names to objects in this cache. */
NSMutableDictionary *_objects;
/** LRU ordering of all potentially-evictable objects in this cache. */
NSMutableArray *_accesses;
/** Total number of accesses to objects */
int64_t _totalAccesses;
#endif
}
/**
* Returns the maximum number of objects that are supported by this cache.
*/
- (NSUInteger)countLimit;
- (NSUInteger) countLimit;
/**
* Returns the cache's delegate.
*/
- (id)delegate;
- (id) delegate;
/**
* Returns whether objects stored in this cache which implement the
* NSDiscardableContent protocol are removed from the cache when their contents
* are evicted.
*/
- (BOOL)evictsObjectsWithDiscardedContent;
- (BOOL) evictsObjectsWithDiscardedContent;
/**
* Returns the name associated with this cache.
*/
- (NSString*)name;
- (NSString*) name;
/**
* Returns an object associated with the specified key in this cache.
*/
- (id)objectForKey: (id)key;
- (id) objectForKey: (id)key;
/**
* Removes all objects from this cache.
*/
- (void)removeAllObjects;
- (void) removeAllObjects;
/**
* Removes the object associated with the given key.
*/
- (void)removeObjectForKey: (id)key;
- (void) removeObjectForKey: (id)key;
/**
* Sets the maximum number of objects permitted in this cache. This limit is
* advisory; caches may choose to disregard it temporarily or permanently. A
* limit of 0 is used to indicate no limit; this is the default.
*/
- (void)setCountLimit: (NSUInteger)lim;;
- (void) setCountLimit: (NSUInteger)lim;;
/**
* Sets the delegate for this cache. The delegate will be notified when an
* object is being evicted or removed from the cache.
*/
- (void)setDelegate:(id)del;
- (void) setDelegate: (id)del;
/**
* Sets whether this cache will evict objects that conform to the
* NSDiscardableContent protocol, or simply discard their contents.
*/
- (void)setEvictsObjectsWithDiscardedContent:(BOOL)b;
- (void) setEvictsObjectsWithDiscardedContent: (BOOL)b;
/**
* Sets the name for this cache.
*/
- (void)setName: (NSString*)cacheName;
- (void) setName: (NSString*)cacheName;
/**
* Adds an object and its associated cost. The cache will endeavor to keep the
* total cost below the value set with -setTotalCostLimit: by discarding the
* contents of objects which implement the NSDiscardableContent protocol.
*/
- (void)setObject: (id)obj forKey: (id)key cost: (NSUInteger)num;
- (void) setObject: (id)obj forKey: (id)key cost: (NSUInteger)num;
/**
* Adds an object to the cache without associating a cost with it.
*/
- (void)setObject: (id)obj forKey: (id)key;
- (void) setObject: (id)obj forKey: (id)key;
/**
* Sets the maximum total cost for objects stored in this cache. This limit is
* advisory; caches may choose to disregard it temporarily or permanently. A
* limit of 0 is used to indicate no limit; this is the default.
*/
- (void)setTotalCostLimit: (NSUInteger)lim;
- (void) setTotalCostLimit: (NSUInteger)lim;
@end
/**
* Protocol implemented by NSCache delegate objects.
*/
@ -107,6 +155,13 @@
* Delegate method, called just before the cache removes an object, either as
* the result of user action or due to the cache becoming full.
*/
- (void)cache: (NSCache*)cache willEvictObject: (id)obj;
- (void) cache: (NSCache*)cache willEvictObject: (id)obj;
@end
#if defined(__cplusplus)
}
#endif
#endif //OS_API_VERSION(MAC_OS_X_VERSION_10_6, GS_API_LATEST)
#endif /* __NSCache_h_GNUSTEP_BASE_INCLUDE */

354
Source/NSCache.m
View file

@ -1,5 +1,36 @@
/* Implementation for NSCache for GNUStep
Copyright (C) 2009 Free Software Foundation, Inc.
Written by: David Chisnall <csdavec@swan.ac.uk>
Created: 2009
This file is part of the GNUstep Base Library.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser 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 Lesser General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02111 USA.
*/
#import "config.h"
#define EXPOSE_GSCACHE_IVARS 1
#import <Foundation/Foundation.h>
#import "Foundation/NSArray.h"
#import "Foundation/NSCache.h"
#import "Foundation/NSDictionary.h"
#import "Foundation/NSEnumerator.h"
#import "Foundation/NSString.h"
/**
* _GSCachedObject is effectively used as a structure containing the various
@ -9,134 +40,157 @@
*/
@interface _GSCachedObject : NSObject
{
@public
id object;
NSString *key;
int accessCount;
NSUInteger cost;
BOOL isEvictable;
@public
id object;
NSString *key;
int accessCount;
NSUInteger cost;
BOOL isEvictable;
}
@end
@interface NSCache (EvictionPolicy)
/** The method controlling eviction policy in an NSCache. */
- (void)_evictObjectsToMakeSpaceForObjectWithCost: (NSUInteger)cost;
- (void) _evictObjectsToMakeSpaceForObjectWithCost: (NSUInteger)cost;
@end
@implementation NSCache
- (id)init
- (id) init
{
if (nil == (self = [super init])) { return nil; }
_objects = [NSMutableDictionary new];
_accesses = [NSMutableArray new];
return self;
if (nil == (self = [super init]))
{
return nil;
}
_objects = [NSMutableDictionary new];
_accesses = [NSMutableArray new];
return self;
}
- (NSUInteger)countLimit
- (NSUInteger) countLimit
{
return _countLimit;
return _countLimit;
}
- (id)delegate
- (id) delegate
{
return _delegate;
return _delegate;
}
- (BOOL)evictsObjectsWithDiscardedContent
- (BOOL) evictsObjectsWithDiscardedContent
{
return _evictsObjectsWithDiscardedContent;
return _evictsObjectsWithDiscardedContent;
}
- (NSString*)name
- (NSString*) name
{
return _name;
return _name;
}
- (id)objectForKey: (id)key
- (id) objectForKey: (id)key
{
_GSCachedObject *obj = [_objects objectForKey: key];
if (nil == obj)
{
return nil;
}
if (obj->isEvictable)
{
// Move the object to the end of the access list.
[_accesses removeObjectIdenticalTo: obj];
[_accesses addObject: obj];
}
obj->accessCount++;
_totalAccesses++;
return obj->object;
_GSCachedObject *obj = [_objects objectForKey: key];
if (nil == obj)
{
return nil;
}
if (obj->isEvictable)
{
// Move the object to the end of the access list.
[_accesses removeObjectIdenticalTo: obj];
[_accesses addObject: obj];
}
obj->accessCount++;
_totalAccesses++;
return obj->object;
}
- (void)removeAllObjects
- (void) removeAllObjects
{
NSEnumerator *e = [_objects objectEnumerator];
_GSCachedObject *obj;
while (nil != (obj = [e nextObject]))
{
[_delegate cache: self willEvictObject: obj->object];
}
[_objects removeAllObjects];
[_accesses removeAllObjects];
_totalAccesses = 0;
NSEnumerator *e = [_objects objectEnumerator];
_GSCachedObject *obj;
while (nil != (obj = [e nextObject]))
{
[_delegate cache: self willEvictObject: obj->object];
}
[_objects removeAllObjects];
[_accesses removeAllObjects];
_totalAccesses = 0;
}
- (void)removeObjectForKey: (id)key
- (void) removeObjectForKey: (id)key
{
_GSCachedObject *obj = [_objects objectForKey: key];
if (nil != obj)
{
[_delegate cache: self willEvictObject: obj->object];
_totalAccesses -= obj->accessCount;
[_objects removeObjectForKey: key];
[_accesses removeObjectIdenticalTo: obj];
}
_GSCachedObject *obj = [_objects objectForKey: key];
if (nil != obj)
{
[_delegate cache: self willEvictObject: obj->object];
_totalAccesses -= obj->accessCount;
[_objects removeObjectForKey: key];
[_accesses removeObjectIdenticalTo: obj];
}
}
- (void)setCountLimit: (NSUInteger)lim
- (void) setCountLimit: (NSUInteger)lim
{
_countLimit = lim;
_countLimit = lim;
}
- (void)setDelegate:(id)del
- (void) setDelegate:(id)del
{
_delegate = del;
_delegate = del;
}
- (void)setEvictsObjectsWithDiscardedContent:(BOOL)b
- (void) setEvictsObjectsWithDiscardedContent:(BOOL)b
{
_evictsObjectsWithDiscardedContent = b;
_evictsObjectsWithDiscardedContent = b;
}
- (void)setName: (NSString*)cacheName
- (void) setName: (NSString*)cacheName
{
ASSIGN(_name, cacheName);
ASSIGN(_name, cacheName);
}
- (void)setObject: (id)obj forKey: (id)key cost: (NSUInteger)num
- (void) setObject: (id)obj forKey: (id)key cost: (NSUInteger)num
{
_GSCachedObject *old = [_objects objectForKey: key];
if (nil != old)
{
[self removeObjectForKey: old->key];
}
[self _evictObjectsToMakeSpaceForObjectWithCost: num];
_GSCachedObject *new = [_GSCachedObject new];
// Retained here, released when obj is dealloc'd
new->object = RETAIN(obj);
new->key = RETAIN(key);
new->cost = num;
if ([obj conformsToProtocol: @protocol(NSDiscardableContent)])
{
new->isEvictable = YES;
[_accesses addObject: new];
}
[_objects setObject: new forKey: key];
RELEASE(obj);
_totalCost += num;
_GSCachedObject *old = [_objects objectForKey: key];
if (nil != old)
{
[self removeObjectForKey: old->key];
}
[self _evictObjectsToMakeSpaceForObjectWithCost: num];
_GSCachedObject *new = [_GSCachedObject new];
// Retained here, released when obj is dealloc'd
new->object = RETAIN(obj);
new->key = RETAIN(key);
new->cost = num;
if ([obj conformsToProtocol: @protocol(NSDiscardableContent)])
{
new->isEvictable = YES;
[_accesses addObject: new];
}
[_objects setObject: new forKey: key];
RELEASE(obj);
_totalCost += num;
}
- (void)setObject: (id)obj forKey: (id)key
- (void) setObject: (id)obj forKey: (id)key
{
[self setObject: obj forKey: key cost: 0];
[self setObject: obj forKey: key cost: 0];
}
- (void)setTotalCostLimit: (NSUInteger)lim
- (void) setTotalCostLimit: (NSUInteger)lim
{
_costLimit = lim;
_costLimit = lim;
}
- (NSUInteger)totalCostLimit
{
return _costLimit;
return _costLimit;
}
/**
* This method is the one that handles the eviction policy. This
* implementation uses a relatively simple LRU/LFU hybrid. The NSCache
@ -146,82 +200,84 @@
*/
- (void)_evictObjectsToMakeSpaceForObjectWithCost: (NSUInteger)cost
{
NSUInteger spaceNeeded = 0;
NSUInteger count = [_objects count];
NSUInteger spaceNeeded = 0;
NSUInteger count = [_objects count];
if (_costLimit > 0 && _totalCost + cost > _costLimit)
if (_costLimit > 0 && _totalCost + cost > _costLimit)
{
spaceNeeded = _totalCost + cost - _costLimit;
}
// Only evict if we need the space.
if (count > 0 && (spaceNeeded > 0 || count >= _countLimit))
{
NSMutableArray *evictedKeys = nil;
// Round up slightly.
NSUInteger averageAccesses = (_totalAccesses / count * 0.2) + 1;
NSEnumerator *e = [_accesses objectEnumerator];
_GSCachedObject *obj;
if (_evictsObjectsWithDiscardedContent)
{
spaceNeeded = _totalCost + cost - _costLimit;
evictedKeys = [[NSMutableArray alloc] init];
}
// Only evict if we need the space.
if (count > 0 && (spaceNeeded > 0 || count >= _countLimit))
while (nil != (obj = [e nextObject]))
{
NSMutableArray *evictedKeys = nil;
// Round up slightly.
NSUInteger averageAccesses = (_totalAccesses / count * 0.2) + 1;
NSEnumerator *e = [_accesses objectEnumerator];
_GSCachedObject *obj;
// Don't evict frequently accessed objects.
if (obj->accessCount < averageAccesses && obj->isEvictable)
{
[obj->object discardContentIfPossible];
if ([obj->object isContentDiscarded])
{
NSUInteger cost = obj->cost;
if (_evictsObjectsWithDiscardedContent)
{
evictedKeys = [[NSMutableArray alloc] init];
}
while (nil != (obj = [e nextObject]))
{
// Don't evict frequently accessed objects.
if (obj->accessCount < averageAccesses && obj->isEvictable)
{
[obj->object discardContentIfPossible];
if ([obj->object isContentDiscarded])
{
NSUInteger cost = obj->cost;
// Evicted objects have no cost.
obj->cost = 0;
// Don't try evicting this again in future; it's gone already.
obj->isEvictable = NO;
// Remove this object as well as its contents if required
if (_evictsObjectsWithDiscardedContent)
{
[evictedKeys addObject: obj->key];
}
_totalCost -= cost;
// If we've freed enough space, give up
if (cost > spaceNeeded)
{
break;
}
spaceNeeded -= cost;
}
}
}
// Evict all of the objects whose content we have discarded if required
if (_evictsObjectsWithDiscardedContent)
{
NSString *key;
e = [evictedKeys objectEnumerator];
while (nil != (key = [e nextObject]))
{
[self removeObjectForKey: key];
}
// Evicted objects have no cost.
obj->cost = 0;
// Don't try evicting this again in future; it's gone already.
obj->isEvictable = NO;
// Remove this object as well as its contents if required
if (_evictsObjectsWithDiscardedContent)
{
[evictedKeys addObject: obj->key];
}
_totalCost -= cost;
// If we've freed enough space, give up
if (cost > spaceNeeded)
{
break;
}
spaceNeeded -= cost;
}
}
}
// Evict all of the objects whose content we have discarded if required
if (_evictsObjectsWithDiscardedContent)
{
NSString *key;
e = [evictedKeys objectEnumerator];
while (nil != (key = [e nextObject]))
{
[self removeObjectForKey: key];
}
}
}
}
- (void)dealloc
- (void) dealloc
{
[_name release];
[_objects release];
[_accesses release];
[super dealloc];
[_name release];
[_objects release];
[_accesses release];
[super dealloc];
}
@end
@implementation _GSCachedObject
- (void)dealloc
{
[object release];
[key release];
[super dealloc];
[object release];
[key release];
[super dealloc];
}
@end