PSPDFThreadSafeMutableDictionary.m

//
// PSPDFThreadSafeMutableDictionary.m
//
// Copyright (c) 2013 Peter Steinberger, PSPDFKit GmbH. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#import <Foundation/Foundation.h>

// Dictionary-Subclasss whose primitive operations are thread safe.
@interface PSPDFThreadSafeMutableDictionary : NSMutableDictionary
@end

// ----------------------------------------------------------------

#import "PSPDFThreadSafeMutableDictionary.h"
#import <libkern/OSAtomic.h>

@implementation PSPDFThreadSafeMutableDictionary {
    OSSpinLock _lock;
    NSMutableDictionary *_dictionary; // Class Cluster
}

///////////////////////////////////////////////////////////////////////////////////////////
#pragma mark - NSObject

- (id)init {
    return [self initWithCapacity:0];
}

- (id)initWithObjects:(NSArray *)objects forKeys:(NSArray *)keys {
    if ((self = [self initWithCapacity:objects.count])) {
        [objects enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
            _dictionary[keys[idx]] = obj;
        }];
    }
    return self;
}

- (id)initWithCapacity:(NSUInteger)capacity {
    if ((self = [super init])) {
        _dictionary = [[NSMutableDictionary alloc] initWithCapacity:capacity];
        _lock = OS_SPINLOCK_INIT;
    }
    return self;
}

///////////////////////////////////////////////////////////////////////////////////////////
#pragma mark - NSMutableDictionary

- (void)setObject:(id)anObject forKey:(id<NSCopying>)aKey {
    OSSpinLockLock(&_lock);
    _dictionary[aKey] = anObject;
    OSSpinLockUnlock(&_lock);
}

- (void)removeObjectForKey:(id)aKey {
    OSSpinLockLock(&_lock);
    [_dictionary removeObjectForKey:aKey];
    OSSpinLockUnlock(&_lock);
}

- (NSUInteger)count {
    OSSpinLockLock(&_lock);
    NSUInteger count = _dictionary.count;
    OSSpinLockUnlock(&_lock);
    return count;
}

- (id)objectForKey:(id)aKey {
    OSSpinLockLock(&_lock);
    id obj = _dictionary[aKey];
    OSSpinLockUnlock(&_lock);
    return obj;
}

- (NSEnumerator *)keyEnumerator {
    OSSpinLockLock(&_lock);
    NSEnumerator *keyEnumerator = [_dictionary keyEnumerator];
    OSSpinLockUnlock(&_lock);
    return keyEnumerator;
}

@end