react-native/React/Base/RCTCache.m

369 lines
9.3 KiB
Objective-C

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
// Adapted from https://github.com/nicklockwood/OSCache
#import "RCTCache.h"
#import "RCTAssert.h"
#import <TargetConditionals.h>
#if TARGET_OS_IPHONE
#import <UIKit/UIKit.h>
#endif
@interface RCTCacheEntry : NSObject
@property (nonatomic, strong) NSObject *object;
@property (nonatomic, assign) NSUInteger cost;
@property (nonatomic, assign) NSInteger sequenceNumber;
@end
@implementation RCTCacheEntry
@end
@interface RCTCache_Private : NSObject
@property (nonatomic, unsafe_unretained) id<RCTCacheDelegate> delegate;
@property (nonatomic, assign) NSUInteger countLimit;
@property (nonatomic, assign) NSUInteger totalCostLimit;
@property (nonatomic, copy) NSString *name;
@property (nonatomic, strong) NSMutableDictionary *cache;
@property (nonatomic, assign) NSUInteger totalCost;
@property (nonatomic, assign) NSInteger sequenceNumber;
@end
@implementation RCTCache_Private
{
BOOL _delegateRespondsToWillEvictObject;
BOOL _delegateRespondsToShouldEvictObject;
BOOL _currentlyCleaning;
NSMutableArray *_entryPool;
NSLock *_lock;
}
- (id)init
{
if ((self = [super init]))
{
//create storage
_cache = [[NSMutableDictionary alloc] init];
_entryPool = [[NSMutableArray alloc] init];
_lock = [[NSLock alloc] init];
_totalCost = 0;
#if TARGET_OS_IPHONE
//clean up in the event of a memory warning
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(cleanUpAllObjects) name:UIApplicationDidReceiveMemoryWarningNotification object:nil];
#endif
}
return self;
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
- (void)setDelegate:(id<RCTCacheDelegate>)delegate
{
_delegate = delegate;
_delegateRespondsToShouldEvictObject = [delegate respondsToSelector:@selector(cache:shouldEvictObject:)];
_delegateRespondsToWillEvictObject = [delegate respondsToSelector:@selector(cache:willEvictObject:)];
}
- (void)setCountLimit:(NSUInteger)countLimit
{
[_lock lock];
_countLimit = countLimit;
[_lock unlock];
[self cleanUp:NO];
}
- (void)setTotalCostLimit:(NSUInteger)totalCostLimit
{
[_lock lock];
_totalCostLimit = totalCostLimit;
[_lock unlock];
[self cleanUp:NO];
}
- (NSUInteger)count
{
return [_cache count];
}
- (void)cleanUp:(BOOL)keepEntries
{
[_lock lock];
NSUInteger maxCount = _countLimit ?: INT_MAX;
NSUInteger maxCost = _totalCostLimit ?: INT_MAX;
NSUInteger totalCount = _cache.count;
NSMutableArray *keys = [_cache.allKeys mutableCopy];
while (totalCount > maxCount || _totalCost > maxCost)
{
NSInteger lowestSequenceNumber = INT_MAX;
RCTCacheEntry *lowestEntry = nil;
id lowestKey = nil;
//remove oldest items until within limit
for (id key in keys)
{
RCTCacheEntry *entry = _cache[key];
if (entry.sequenceNumber < lowestSequenceNumber)
{
lowestSequenceNumber = entry.sequenceNumber;
lowestEntry = entry;
lowestKey = key;
}
}
if (lowestKey)
{
[keys removeObject:lowestKey];
if (!_delegateRespondsToShouldEvictObject ||
[_delegate cache:(RCTCache *)self shouldEvictObject:lowestEntry.object])
{
if (_delegateRespondsToWillEvictObject)
{
_currentlyCleaning = YES;
[self.delegate cache:(RCTCache *)self willEvictObject:lowestEntry.object];
_currentlyCleaning = NO;
}
[_cache removeObjectForKey:lowestKey];
_totalCost -= lowestEntry.cost;
totalCount --;
if (keepEntries)
{
[_entryPool addObject:lowestEntry];
lowestEntry.object = nil;
}
}
}
}
[_lock unlock];
}
- (void)cleanUpAllObjects
{
[_lock lock];
if (_delegateRespondsToShouldEvictObject || _delegateRespondsToWillEvictObject)
{
NSArray *keys = [_cache allKeys];
if (_delegateRespondsToShouldEvictObject)
{
//sort, oldest first (in case we want to use that information in our eviction test)
keys = [keys sortedArrayUsingComparator:^NSComparisonResult(id key1, id key2) {
RCTCacheEntry *entry1 = self->_cache[key1];
RCTCacheEntry *entry2 = self->_cache[key2];
return (NSComparisonResult)MIN(1, MAX(-1, entry1.sequenceNumber - entry2.sequenceNumber));
}];
}
//remove all items individually
for (id key in keys)
{
RCTCacheEntry *entry = _cache[key];
if (!_delegateRespondsToShouldEvictObject || [_delegate cache:(RCTCache *)self shouldEvictObject:entry.object])
{
if (_delegateRespondsToWillEvictObject)
{
_currentlyCleaning = YES;
[_delegate cache:(RCTCache *)self willEvictObject:entry.object];
_currentlyCleaning = NO;
}
[_cache removeObjectForKey:key];
_totalCost -= entry.cost;
}
}
}
else
{
_totalCost = 0;
[_cache removeAllObjects];
_sequenceNumber = 0;
}
[_lock unlock];
}
- (void)resequence
{
//sort, oldest first
NSArray *entries = [[_cache allValues] sortedArrayUsingComparator:^NSComparisonResult(RCTCacheEntry *entry1, RCTCacheEntry *entry2) {
return (NSComparisonResult)MIN(1, MAX(-1, entry1.sequenceNumber - entry2.sequenceNumber));
}];
//renumber items
NSInteger index = 0;
for (RCTCacheEntry *entry in entries)
{
entry.sequenceNumber = index++;
}
}
- (id)objectForKey:(id)key
{
[_lock lock];
RCTCacheEntry *entry = _cache[key];
entry.sequenceNumber = _sequenceNumber++;
if (_sequenceNumber < 0)
{
[self resequence];
}
id object = entry.object;
[_lock unlock];
return object;
}
- (id)objectForKeyedSubscript:(id<NSCopying>)key
{
return [self objectForKey:key];
}
- (void)setObject:(id)obj forKey:(id)key
{
[self setObject:obj forKey:key cost:0];
}
- (void)setObject:(id)obj forKeyedSubscript:(id<NSCopying>)key
{
[self setObject:obj forKey:key cost:0];
}
- (void)setObject:(id)obj forKey:(id)key cost:(NSUInteger)g
{
if (!obj)
{
[self removeObjectForKey:key];
return;
}
RCTAssert(!_currentlyCleaning, @"It is not possible to modify cache from within the implementation of this delegate method.");
[_lock lock];
_totalCost -= [_cache[key] cost];
_totalCost += g;
RCTCacheEntry *entry = _cache[key];
if (!entry) {
entry = [[RCTCacheEntry alloc] init];
_cache[key] = entry;
}
entry.object = obj;
entry.cost = g;
entry.sequenceNumber = _sequenceNumber++;
if (_sequenceNumber < 0)
{
[self resequence];
}
[_lock unlock];
[self cleanUp:YES];
}
- (void)removeObjectForKey:(id)key
{
RCTAssert(!_currentlyCleaning, @"It is not possible to modify cache from within the implementation of this delegate method.");
[_lock lock];
RCTCacheEntry *entry = _cache[key];
if (entry) {
_totalCost -= entry.cost;
entry.object = nil;
[_entryPool addObject:entry];
[_cache removeObjectForKey:key];
}
[_lock unlock];
}
- (void)removeAllObjects
{
RCTAssert(!_currentlyCleaning, @"It is not possible to modify cache from within the implementation of this delegate method.");
[_lock lock];
_totalCost = 0;
_sequenceNumber = 0;
for (RCTCacheEntry *entry in _cache.allValues)
{
entry.object = nil;
[_entryPool addObject:entry];
}
[_cache removeAllObjects];
[_lock unlock];
}
- (NSUInteger)countByEnumeratingWithState:(NSFastEnumerationState *)state
objects:(id __unsafe_unretained [])buffer
count:(NSUInteger)len
{
[_lock lock];
NSUInteger count = [_cache countByEnumeratingWithState:state objects:buffer count:len];
[_lock unlock];
return count;
}
- (void)enumerateKeysAndObjectsUsingBlock:(void (^)(id key, id obj, BOOL *stop))block
{
[_lock lock];
[_cache enumerateKeysAndObjectsUsingBlock:block];
[_lock unlock];
}
//handle unimplemented methods
- (BOOL)isKindOfClass:(Class)aClass
{
//pretend that we're an RCTCache if anyone asks
if (aClass == [RCTCache class] || aClass == [NSCache class])
{
return YES;
}
return [super isKindOfClass:aClass];
}
- (NSMethodSignature *)methodSignatureForSelector:(SEL)selector
{
//protect against calls to unimplemented NSCache methods
NSMethodSignature *signature = [super methodSignatureForSelector:selector];
if (!signature)
{
signature = [NSCache instanceMethodSignatureForSelector:selector];
}
return signature;
}
- (void)forwardInvocation:(NSInvocation *)invocation
{
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wnonnull"
[invocation invokeWithTarget:nil];
#pragma clang diagnostic pop
}
@end
@implementation RCTCache
+ (id)alloc
{
return (RCTCache *)[RCTCache_Private alloc];
}
- (id)objectForKeyedSubscript:(__unused id<NSCopying>)key { return nil; }
- (void)setObject:(__unused id)obj forKeyedSubscript:(__unused id<NSCopying>)key {}
- (void)enumerateKeysAndObjectsUsingBlock:(__unused void (^)(id, id, BOOL *))block { }
- (NSUInteger)countByEnumeratingWithState:(__unused NSFastEnumerationState *)state
objects:(__unused __unsafe_unretained id [])buffer
count:(__unused NSUInteger)len { return 0; }
@end