mirrors
/
SDWebImage
mirror of https://github.com/SDWebImage/SDWebImage.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Use dispatch_barrier to handle NSMutableDictionary thread unsafety instead of main thread dispatching

This commit is contained in:
Olivier Poitrey 2012-11-06 03:31:03 +01:00
parent 13210a6925
commit 570965f6cf
1 changed files with 73 additions and 57 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

130
SDWebImage/SDWebImageDownloader.m
View File

@ -20,6 +20,7 @@ NSString *const kCompletedCallbackKey = @"completed";
@property (strong, nonatomic) NSOperationQueue *downloadQueue; @property (strong, nonatomic) NSOperationQueue *downloadQueue;
@property (strong, nonatomic) NSMutableDictionary *URLCallbacks; @property (strong, nonatomic) NSMutableDictionary *URLCallbacks;
@property (assign, nonatomic) dispatch_queue_t barrierQueue;
@end @end
@ -65,6 +66,7 @@ NSString *const kCompletedCallbackKey = @"completed";
_downloadQueue = NSOperationQueue.new; _downloadQueue = NSOperationQueue.new;
_downloadQueue.maxConcurrentOperationCount = 10; _downloadQueue.maxConcurrentOperationCount = 10;
_URLCallbacks = NSMutableDictionary.new; _URLCallbacks = NSMutableDictionary.new;
_barrierQueue = dispatch_queue_create("com.hackemist.SDWebImageDownloaderBarrierQueue", DISPATCH_QUEUE_CONCURRENT);
} }
return self; return self;
} }
@ -82,71 +84,85 @@ NSString *const kCompletedCallbackKey = @"completed";
- (NSOperation *)downloadImageWithURL:(NSURL *)url options:(SDWebImageDownloaderOptions)options progress:(void (^)(NSUInteger, long long))progressBlock completed:(void (^)(UIImage *, NSError *, BOOL))completedBlock - (NSOperation *)downloadImageWithURL:(NSURL *)url options:(SDWebImageDownloaderOptions)options progress:(void (^)(NSUInteger, long long))progressBlock completed:(void (^)(UIImage *, NSError *, BOOL))completedBlock
{ {
__block SDWebImageDownloaderOperation *operation; __block SDWebImageDownloaderOperation *operation;
__weak SDWebImageDownloader *wself = self;
dispatch_async(dispatch_get_main_queue(), ^ // NSDictionary isn't thread safe [self addProgressCallback:progressBlock andCompletedBlock:completedBlock forURL:url createCallback:^
{ {
BOOL performDownload = NO; // In order to prevent from potential duplicate caching (NSURLCache + SDImageCache) we disable the cache for image requests
NSMutableURLRequest *request = [NSMutableURLRequest.alloc initWithURL:url cachePolicy:NSURLCacheStorageNotAllowed timeoutInterval:15];
if (!self.URLCallbacks[url]) request.HTTPShouldHandleCookies = NO;
request.HTTPShouldUsePipelining = YES;
[request addValue:@"image/*" forHTTPHeaderField:@"Accept"];
operation = [SDWebImageDownloaderOperation.alloc initWithRequest:request options:options progress:^(NSUInteger receivedSize, long long expectedSize)
{ {
self.URLCallbacks[url] = NSMutableArray.new; if (!wself) return;
performDownload = YES; SDWebImageDownloader *sself = wself;
} NSArray *callbacksForURL = [sself removeAndReturnCallbacksForURL:url];
for (NSDictionary *callbacks in callbacksForURL)
// Handle single download of simultaneous download request for the same URL
{
NSMutableArray *callbacksForURL = self.URLCallbacks[url];
NSMutableDictionary *callbacks = NSMutableDictionary.new;
if (progressBlock) callbacks[kProgressCallbackKey] = progressBlock;
if (completedBlock) callbacks[kCompletedCallbackKey] = completedBlock;
[callbacksForURL addObject:callbacks];
self.URLCallbacks[url] = callbacksForURL;
}
if (performDownload)
{
// In order to prevent from potential duplicate caching (NSURLCache + SDImageCache) we disable the cache for image requests
NSMutableURLRequest *request = [NSMutableURLRequest.alloc initWithURL:url cachePolicy:NSURLCacheStorageNotAllowed timeoutInterval:15];
request.HTTPShouldHandleCookies = NO;
request.HTTPShouldUsePipelining = YES;
[request addValue:@"image/*" forHTTPHeaderField:@"Accept"];
operation = [SDWebImageDownloaderOperation.alloc initWithRequest:request options:options progress:^(NSUInteger receivedSize, long long expectedSize)
{ {
dispatch_async(dispatch_get_main_queue(), ^ SDWebImageDownloaderProgressBlock callback = callbacks[kProgressCallbackKey];
{ if (callback) callback(receivedSize, expectedSize);
NSMutableArray *callbacksForURL = self.URLCallbacks[url];
for (NSDictionary *callbacks in callbacksForURL)
{
SDWebImageDownloaderProgressBlock callback = callbacks[kProgressCallbackKey];
if (callback) callback(receivedSize, expectedSize);
}
});
} }
completed:^(UIImage *image, NSError *error, BOOL finished)
{
dispatch_async(dispatch_get_main_queue(), ^
{
NSMutableArray *callbacksForURL = self.URLCallbacks[url];
[self.URLCallbacks removeObjectForKey:url];
for (NSDictionary *callbacks in callbacksForURL)
{
SDWebImageDownloaderCompletedBlock callback = callbacks[kCompletedCallbackKey];
if (callback) callback(image, error, finished);
}
});
}
cancelled:^
{
dispatch_async(dispatch_get_main_queue(), ^
{
[self.URLCallbacks removeObjectForKey:url];
});
}];
[self.downloadQueue addOperation:operation];
} }
}); completed:^(UIImage *image, NSError *error, BOOL finished)
{
if (!wself) return;
SDWebImageDownloader *sself = wself;
NSArray *callbacksForURL = [sself removeAndReturnCallbacksForURL:url];
for (NSDictionary *callbacks in callbacksForURL)
{
SDWebImageDownloaderCompletedBlock callback = callbacks[kCompletedCallbackKey];
if (callback) callback(image, error, finished);
}
}
cancelled:^
{
if (!wself) return;
SDWebImageDownloader *sself = wself;
[sself removeAndReturnCallbacksForURL:url];
}];
[self.downloadQueue addOperation:operation];
}];
return operation; return operation;
} }
- (void)addProgressCallback:(void (^)(NSUInteger, long long))progressBlock andCompletedBlock:(void (^)(UIImage *, NSError *, BOOL))completedBlock forURL:(NSURL *)url createCallback:(void (^)())createCallback
{
dispatch_barrier_async(self.barrierQueue, ^
{
BOOL first = NO;
if (!self.URLCallbacks[url])
{
self.URLCallbacks[url] = NSMutableArray.new;
first = YES;
}
// Handle single download of simultaneous download request for the same URL
NSMutableArray *callbacksForURL = self.URLCallbacks[url];
NSMutableDictionary *callbacks = NSMutableDictionary.new;
if (progressBlock) callbacks[kProgressCallbackKey] = progressBlock;
if (completedBlock) callbacks[kCompletedCallbackKey] = completedBlock;
[callbacksForURL addObject:callbacks];
self.URLCallbacks[url] = callbacksForURL;
if (first)
{
createCallback();
}
});
}
- (NSArray *)removeAndReturnCallbacksForURL:(NSURL *)url
{
__block NSArray *callbacksForURL;
dispatch_barrier_sync(self.barrierQueue, ^
{
callbacksForURL = self.URLCallbacks[url];
[self.URLCallbacks removeObjectForKey:url];
});
return callbacksForURL;
}
@end @end