Merge pull request #1586 from oanapopescu/nsurlsession

Updated image downloader with a single session that manages all tasks

@@ -13,7 +13,7 @@
 static NSString *const kProgressCallbackKey = @"progress";
 static NSString *const kCompletedCallbackKey = @"completed";
 
-@interface SDWebImageDownloader ()
+@interface SDWebImageDownloader () <NSURLSessionTaskDelegate, NSURLSessionDataDelegate>
 
 @property (strong, nonatomic) NSOperationQueue *downloadQueue;
 @property (weak, nonatomic) NSOperation *lastAddedOperation;
@@ -23,6 +23,9 @@ static NSString *const kCompletedCallbackKey = @"completed";
 // This queue is used to serialize the handling of the network responses of all the download operation in a single queue
 @property (SDDispatchQueueSetterSementics, nonatomic) dispatch_queue_t barrierQueue;
 
+// The session in which data tasks will run
+@property (strong, nonatomic) NSURLSession *session;
+
 @end
 
 @implementation SDWebImageDownloader
@@ -74,11 +77,26 @@ static NSString *const kCompletedCallbackKey = @"completed";
 #endif
         _barrierQueue = dispatch_queue_create("com.hackemist.SDWebImageDownloaderBarrierQueue", DISPATCH_QUEUE_CONCURRENT);
         _downloadTimeout = 15.0;
+
+        NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration];
+        sessionConfig.timeoutIntervalForRequest = _downloadTimeout;
+
+        /**
+         *  Create the session for this task
+         *  We send nil as delegate queue so that the session creates a serial operation queue for performing all delegate
+         *  method calls and completion handler calls.
+         */
+        self.session = [NSURLSession sessionWithConfiguration:sessionConfig
+                                                     delegate:self
+                                                delegateQueue:nil];
     }
     return self;
 }
 
 - (void)dealloc {
+    [self.session invalidateAndCancel];
+    self.session = nil;
+
     [self.downloadQueue cancelAllOperations];
     SDDispatchQueueRelease(_barrierQueue);
 }
@@ -133,6 +151,7 @@ static NSString *const kCompletedCallbackKey = @"completed";
             request.allHTTPHeaderFields = wself.HTTPHeaders;
         }
         operation = [[wself.operationClass alloc] initWithRequest:request
+                                                        inSession:self.session
                                                           options:options
                                                          progress:^(NSInteger receivedSize, NSInteger expectedSize) {
                                                              SDWebImageDownloader *sself = wself;
@@ -233,4 +252,66 @@ static NSString *const kCompletedCallbackKey = @"completed";
     [self.downloadQueue cancelAllOperations];
 }
 
+#pragma mark Helper methods
+
+- (SDWebImageDownloaderOperation *)operationWithTask:(NSURLSessionTask *)task {
+    SDWebImageDownloaderOperation *returnOperation = nil;
+    for (SDWebImageDownloaderOperation *operation in self.downloadQueue.operations) {
+        if (operation.dataTask.taskIdentifier == task.taskIdentifier) {
+            returnOperation = operation;
+            break;
+        }
+    }
+    return returnOperation;
+}
+
+#pragma mark NSURLSessionDataDelegate
+
+- (void)URLSession:(NSURLSession *)session
+          dataTask:(NSURLSessionDataTask *)dataTask
+didReceiveResponse:(NSURLResponse *)response
+ completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler {
+
+    // Identify the operation that runs this task and pass it the delegate method
+    SDWebImageDownloaderOperation *dataOperation = [self operationWithTask:dataTask];
+
+    [dataOperation URLSession:session dataTask:dataTask didReceiveResponse:response completionHandler:completionHandler];
+}
+
+- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
+
+    // Identify the operation that runs this task and pass it the delegate method
+    SDWebImageDownloaderOperation *dataOperation = [self operationWithTask:dataTask];
+
+    [dataOperation URLSession:session dataTask:dataTask didReceiveData:data];
+}
+
+- (void)URLSession:(NSURLSession *)session
+          dataTask:(NSURLSessionDataTask *)dataTask
+ willCacheResponse:(NSCachedURLResponse *)proposedResponse
+ completionHandler:(void (^)(NSCachedURLResponse *cachedResponse))completionHandler {
+
+    // Identify the operation that runs this task and pass it the delegate method
+    SDWebImageDownloaderOperation *dataOperation = [self operationWithTask:dataTask];
+
+    [dataOperation URLSession:session dataTask:dataTask willCacheResponse:proposedResponse completionHandler:completionHandler];
+}
+
+#pragma mark NSURLSessionTaskDelegate
+
+- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
+    // Identify the operation that runs this task and pass it the delegate method
+    SDWebImageDownloaderOperation *dataOperation = [self operationWithTask:task];
+
+    [dataOperation URLSession:session task:task didCompleteWithError:error];
+}
+
+- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler {
+
+    // Identify the operation that runs this task and pass it the delegate method
+    SDWebImageDownloaderOperation *dataOperation = [self operationWithTask:task];
+
+    [dataOperation URLSession:session task:task didReceiveChallenge:challenge completionHandler:completionHandler];
+}
+
 @end

@@ -15,13 +15,18 @@ extern NSString *const SDWebImageDownloadReceiveResponseNotification;
 extern NSString *const SDWebImageDownloadStopNotification;
 extern NSString *const SDWebImageDownloadFinishNotification;
 
-@interface SDWebImageDownloaderOperation : NSOperation <SDWebImageOperation>
+@interface SDWebImageDownloaderOperation : NSOperation <SDWebImageOperation, NSURLSessionTaskDelegate, NSURLSessionDataDelegate>
 
 /**
- * The request used by the operation's connection.
+ * The request used by the operation's task.
  */
 @property (strong, nonatomic, readonly) NSURLRequest *request;
 
+/**
+ * The operation's task
+ */
+@property (strong, nonatomic, readonly) NSURLSessionTask *dataTask;
+
 
 @property (assign, nonatomic) BOOL shouldDecompressImages;
 
@@ -53,6 +58,7 @@ extern NSString *const SDWebImageDownloadFinishNotification;
  *  @see SDWebImageDownloaderOperation
  *
  *  @param request        the URL request
+ *  @param session        the URL session in which this operation will run
  *  @param options        downloader options
  *  @param progressBlock  the block executed when a new chunk of data arrives. 
  *                        @note the progress block is executed on a background queue
@@ -63,9 +69,32 @@ extern NSString *const SDWebImageDownloadFinishNotification;
  *  @return the initialized instance
  */
 - (id)initWithRequest:(NSURLRequest *)request
+            inSession:(NSURLSession *)session
               options:(SDWebImageDownloaderOptions)options
              progress:(SDWebImageDownloaderProgressBlock)progressBlock
             completed:(SDWebImageDownloaderCompletedBlock)completedBlock
             cancelled:(SDWebImageNoParamsBlock)cancelBlock;
 
+/**
+ *  Initializes a `SDWebImageDownloaderOperation` object
+ *
+ *  @see SDWebImageDownloaderOperation
+ *
+ *  @param request        the URL request
+ *  @param options        downloader options
+ *  @param progressBlock  the block executed when a new chunk of data arrives.
+ *                        @note the progress block is executed on a background queue
+ *  @param completedBlock the block executed when the download is done.
+ *                        @note the completed block is executed on the main queue for success. If errors are found, there is a chance the block will be executed on a background queue
+ *  @param cancelBlock    the block executed if the download (operation) is cancelled
+ *
+ *  @return the initialized instance. The operation will run in a separate session created for this operation
+ */
+- (id)initWithRequest:(NSURLRequest *)request
+              options:(SDWebImageDownloaderOptions)options
+             progress:(SDWebImageDownloaderProgressBlock)progressBlock
+            completed:(SDWebImageDownloaderCompletedBlock)completedBlock
+            cancelled:(SDWebImageNoParamsBlock)cancelBlock
+__deprecated_msg("Method deprecated. Use `initWithRequest:inSession:options:progress:completed:cancelled`");
+
 @end

@@ -17,7 +17,7 @@ NSString *const SDWebImageDownloadReceiveResponseNotification = @"SDWebImageDown
 NSString *const SDWebImageDownloadStopNotification = @"SDWebImageDownloadStopNotification";
 NSString *const SDWebImageDownloadFinishNotification = @"SDWebImageDownloadFinishNotification";
 
-@interface SDWebImageDownloaderOperation () <NSURLSessionTaskDelegate>
+@interface SDWebImageDownloaderOperation ()
 
 @property (copy, nonatomic) SDWebImageDownloaderProgressBlock progressBlock;
 @property (copy, nonatomic) SDWebImageDownloaderCompletedBlock completedBlock;
@@ -27,8 +27,13 @@ NSString *const SDWebImageDownloadFinishNotification = @"SDWebImageDownloadFinis
 @property (assign, nonatomic, getter = isFinished) BOOL finished;
 @property (strong, nonatomic) NSMutableData *imageData;
 
-@property (strong, nonatomic) NSURLSession *session;
-@property (strong, nonatomic) NSURLSessionDataTask *dataTask;
+// This is weak because it is injected by whoever manages this session. If this gets nil-ed out, we won't be able to run
+// the task associated with this operation
+@property (weak, nonatomic) NSURLSession *unownedSession;
+// This is set if we're using not using an injected NSURLSession. We're responsible of invalidating this one
+@property (strong, nonatomic) NSURLSession *ownedSession;
+
+@property (strong, nonatomic, readwrite) NSURLSessionTask *dataTask;
 
 @property (strong, atomic) NSThread *thread;
 
@@ -52,6 +57,21 @@ NSString *const SDWebImageDownloadFinishNotification = @"SDWebImageDownloadFinis
              progress:(SDWebImageDownloaderProgressBlock)progressBlock
             completed:(SDWebImageDownloaderCompletedBlock)completedBlock
             cancelled:(SDWebImageNoParamsBlock)cancelBlock {
+
+    return [self initWithRequest:request
+                       inSession:nil
+                         options:options
+                        progress:progressBlock
+                       completed:completedBlock
+                       cancelled:cancelBlock];
+}
+
+- (id)initWithRequest:(NSURLRequest *)request
+            inSession:(NSURLSession *)session
+              options:(SDWebImageDownloaderOptions)options
+             progress:(SDWebImageDownloaderProgressBlock)progressBlock
+            completed:(SDWebImageDownloaderCompletedBlock)completedBlock
+            cancelled:(SDWebImageNoParamsBlock)cancelBlock {
     if ((self = [super init])) {
         _request = request;
         _shouldDecompressImages = YES;
@@ -62,6 +82,7 @@ NSString *const SDWebImageDownloadFinishNotification = @"SDWebImageDownloadFinis
         _executing = NO;
         _finished = NO;
         _expectedSize = 0;
+        _unownedSession = session;
         responseFromCached = YES; // Initially wrong until `- URLSession:dataTask:willCacheResponse:completionHandler: is called or not called
     }
     return self;
@@ -93,20 +114,24 @@ NSString *const SDWebImageDownloadFinishNotification = @"SDWebImageDownloadFinis
             }];
         }
 #endif
-        NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration];
-        sessionConfig.timeoutIntervalForRequest = 15;
-        
-        /**
-         *  Create the session for this task
-         *  We send nil as delegate queue so that the session creates a serial operation queue for performing all delegate
-         *  method calls and completion handler calls.
-         */
-        self.session = [NSURLSession sessionWithConfiguration:sessionConfig
-                                                     delegate:self
-                                                delegateQueue:nil];
+        NSURLSession *session = self.unownedSession;
+        if (!self.unownedSession) {
+            NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration];
+            sessionConfig.timeoutIntervalForRequest = 15;
+            
+            /**
+             *  Create the session for this task
+             *  We send nil as delegate queue so that the session creates a serial operation queue for performing all delegate
+             *  method calls and completion handler calls.
+             */
+            self.ownedSession = [NSURLSession sessionWithConfiguration:sessionConfig
+                                                              delegate:self
+                                                         delegateQueue:nil];
+            session = self.ownedSession;
+        }
         
+        self.dataTask = [session dataTaskWithRequest:self.request];
         self.executing = YES;
-        self.dataTask = [self.session dataTaskWithRequest:self.request];
         self.thread = [NSThread currentThread];
     }
     
@@ -188,8 +213,10 @@ NSString *const SDWebImageDownloadFinishNotification = @"SDWebImageDownloadFinis
     self.dataTask = nil;
     self.imageData = nil;
     self.thread = nil;
-    [self.session invalidateAndCancel];
-    self.session = nil;
+    if (self.ownedSession) {
+        [self.ownedSession invalidateAndCancel];
+        self.ownedSession = nil;
+    }
 }
 
 - (void)setFinished:(BOOL)finished {
@@ -208,7 +235,7 @@ NSString *const SDWebImageDownloadFinishNotification = @"SDWebImageDownloadFinis
     return YES;
 }
 
-#pragma mark NSURLSessionTaskDelegate
+#pragma mark NSURLSessionDataDelegate
 
 - (void)URLSession:(NSURLSession *)session
           dataTask:(NSURLSessionDataTask *)dataTask
@@ -339,32 +366,24 @@ didReceiveResponse:(NSURLResponse *)response
     }
 }
 
-+ (UIImageOrientation)orientationFromPropertyValue:(NSInteger)value {
-    switch (value) {
-        case 1:
-            return UIImageOrientationUp;
-        case 3:
-            return UIImageOrientationDown;
-        case 8:
-            return UIImageOrientationLeft;
-        case 6:
-            return UIImageOrientationRight;
-        case 2:
-            return UIImageOrientationUpMirrored;
-        case 4:
-            return UIImageOrientationDownMirrored;
-        case 5:
-            return UIImageOrientationLeftMirrored;
-        case 7:
-            return UIImageOrientationRightMirrored;
-        default:
-            return UIImageOrientationUp;
+- (void)URLSession:(NSURLSession *)session
+          dataTask:(NSURLSessionDataTask *)dataTask
+ willCacheResponse:(NSCachedURLResponse *)proposedResponse
+ completionHandler:(void (^)(NSCachedURLResponse *cachedResponse))completionHandler {
+
+    responseFromCached = NO; // If this method is called, it means the response wasn't read from cache
+    NSCachedURLResponse *cachedResponse = proposedResponse;
+
+    if (self.request.cachePolicy == NSURLRequestReloadIgnoringLocalCacheData) {
+        // Prevents caching of responses
+        cachedResponse = nil;
+    }
+    if (completionHandler) {
+        completionHandler(cachedResponse);
     }
 }
 
-- (UIImage *)scaledImageForKey:(NSString *)key image:(UIImage *)image {
-    return SDScaledImageForKey(key, image);
-}
+#pragma mark NSURLSessionTaskDelegate
 
 - (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
     @synchronized(self) {
@@ -419,32 +438,7 @@ didReceiveResponse:(NSURLResponse *)response
     [self done];
 }
 
-- (void)URLSession:(NSURLSession *)session
-          dataTask:(NSURLSessionDataTask *)dataTask
- willCacheResponse:(NSCachedURLResponse *)proposedResponse
- completionHandler:(void (^)(NSCachedURLResponse *cachedResponse))completionHandler {
-    
-    responseFromCached = NO; // If this method is called, it means the response wasn't read from cache
-    NSCachedURLResponse *cachedResponse = proposedResponse;
-
-    if (self.request.cachePolicy == NSURLRequestReloadIgnoringLocalCacheData) {
-        // Prevents caching of responses
-        cachedResponse = nil;
-    }
-    if (completionHandler) {
-        completionHandler(cachedResponse);
-    }
-}
-
-- (BOOL)shouldContinueWhenAppEntersBackground {
-    return self.options & SDWebImageDownloaderContinueInBackground;
-}
-
-- (void)URLSession:(NSURLSession *)session
-              task:(NSURLSessionTask *)task
-didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge
- completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition,
-                             NSURLCredential *credential))completionHandler {
+- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler {
     
     NSURLSessionAuthChallengeDisposition disposition = NSURLSessionAuthChallengePerformDefaultHandling;
     __block NSURLCredential *credential = nil;
@@ -474,4 +468,37 @@ didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge
     }
 }
 
+#pragma mark Helper methods
+
++ (UIImageOrientation)orientationFromPropertyValue:(NSInteger)value {
+    switch (value) {
+        case 1:
+            return UIImageOrientationUp;
+        case 3:
+            return UIImageOrientationDown;
+        case 8:
+            return UIImageOrientationLeft;
+        case 6:
+            return UIImageOrientationRight;
+        case 2:
+            return UIImageOrientationUpMirrored;
+        case 4:
+            return UIImageOrientationDownMirrored;
+        case 5:
+            return UIImageOrientationLeftMirrored;
+        case 7:
+            return UIImageOrientationRightMirrored;
+        default:
+            return UIImageOrientationUp;
+    }
+}
+
+- (UIImage *)scaledImageForKey:(NSString *)key image:(UIImage *)image {
+    return SDScaledImageForKey(key, image);
+}
+
+- (BOOL)shouldContinueWhenAppEntersBackground {
+    return self.options & SDWebImageDownloaderContinueInBackground;
+}
+
 @end