1/*
2 File: JAHPQNSURLSessionDemux.m
3 Abstract: A general class to demux NSURLSession delegate callbacks.
4 Version: 1.1
5
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44 Copyright (C) 2014 Apple Inc. All Rights Reserved.
45
46 */
47
48#import "JAHPQNSURLSessionDemux.h"
49
50@interface JAHPQNSURLSessionDemuxTaskInfo : NSObject
51
52- (instancetype)initWithTask:(NSURLSessionDataTask *)task delegate:(id<NSURLSessionDataDelegate>)delegate modes:(NSArray *)modes;
53
54@property (atomic, strong, readonly ) NSURLSessionDataTask *        task;
55@property (atomic, strong, readonly ) id<NSURLSessionDataDelegate>  delegate;
56@property (atomic, strong, readonly ) NSThread *                    thread;
57@property (atomic, copy,   readonly ) NSArray *                     modes;
58
59- (void)performBlock:(dispatch_block_t)block;
60
61- (void)invalidate;
62
63@end
64
65@interface JAHPQNSURLSessionDemuxTaskInfo ()
66
67@property (atomic, strong, readwrite) id<NSURLSessionDataDelegate>  delegate;
68@property (atomic, strong, readwrite) NSThread *                    thread;
69
70@end
71
72@implementation JAHPQNSURLSessionDemuxTaskInfo
73
74- (instancetype)initWithTask:(NSURLSessionDataTask *)task delegate:(id<NSURLSessionDataDelegate>)delegate modes:(NSArray *)modes
75{
76    assert(task != nil);
77    assert(delegate != nil);
78    assert(modes != nil);
79
80    self = [super init];
81    if (self != nil) {
82        self->_task = task;
83        self->_delegate = delegate;
84        self->_thread = [NSThread currentThread];
85        self->_modes = [modes copy];
86    }
87    return self;
88}
89
90- (void)performBlock:(dispatch_block_t)block
91{
92    assert(self.delegate != nil);
93    assert(self.thread != nil);
94    [self performSelector:@selector(performBlockOnClientThread:) onThread:self.thread withObject:[block copy] waitUntilDone:NO modes:self.modes];
95}
96
97- (void)performBlockOnClientThread:(dispatch_block_t)block
98{
99    assert([NSThread currentThread] == self.thread);
100    block();
101}
102
103- (void)invalidate
104{
105    self.delegate = nil;
106    self.thread = nil;
107}
108
109@end
110
111@interface JAHPQNSURLSessionDemux () <NSURLSessionDataDelegate>
112
113@property (atomic, strong, readonly ) NSMutableDictionary * taskInfoByTaskID;       // keys NSURLSessionTask taskIdentifier, values are SessionManager
114@property (atomic, strong, readonly ) NSOperationQueue *    sessionDelegateQueue;
115
116@end
117
118@implementation JAHPQNSURLSessionDemux
119
120- (instancetype)init
121{
122    return [self initWithConfiguration:nil];
123}
124
125- (instancetype)initWithConfiguration:(NSURLSessionConfiguration *)configuration
126{
127    // configuration may be nil
128    self = [super init];
129    if (self != nil) {
130        if (configuration == nil) {
131            configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
132        }
133        self->_configuration = [configuration copy];
134
135        self->_taskInfoByTaskID = [[NSMutableDictionary alloc] init];
136
137        self->_sessionDelegateQueue = [[NSOperationQueue alloc] init];
138        [self->_sessionDelegateQueue setMaxConcurrentOperationCount:1];
139        [self->_sessionDelegateQueue setName:@"JAHPQNSURLSessionDemux"];
140
141        self->_session = [NSURLSession sessionWithConfiguration:self->_configuration delegate:self delegateQueue:self->_sessionDelegateQueue];
142        self->_session.sessionDescription = @"JAHPQNSURLSessionDemux";
143    }
144    return self;
145}
146
147- (NSURLSessionDataTask *)dataTaskWithRequest:(NSURLRequest *)request delegate:(id<NSURLSessionDataDelegate>)delegate modes:(NSArray *)modes
148{
149    NSURLSessionDataTask *          task;
150    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
151
152    assert(request != nil);
153    assert(delegate != nil);
154    // modes may be nil
155
156    if ([modes count] == 0) {
157        modes = @[ NSDefaultRunLoopMode ];
158    }
159
160    task = [self.session dataTaskWithRequest:request];
161    assert(task != nil);
162
163    taskInfo = [[JAHPQNSURLSessionDemuxTaskInfo alloc] initWithTask:task delegate:delegate modes:modes];
164
165    @synchronized (self) {
166        self.taskInfoByTaskID[@(task.taskIdentifier)] = taskInfo;
167    }
168
169    return task;
170}
171
172- (JAHPQNSURLSessionDemuxTaskInfo *)taskInfoForTask:(NSURLSessionTask *)task
173{
174    // rdar://21484589
175    // This is called from each NSURLSessionTaskDelegate
176    // method implemented by JAHPQNSURLSessionDemux,
177    // which are called from the NSURLSession delegateQueue,
178    // which is a different thread than self.clientThread.
179    // It is possible that -stopLoading was called on self.clientThread
180    // just before this method if so, we cannot make the
181    // assertion (task != nil).
182
183    // rdar://24042545
184    // URLSession:task:didCompleteWithError: should always
185    // be the last NSURLSessionTaskDelegate method called.
186    // Although, it is possible that this is not always
187    // the case. Therefore we cannot make the assertion
188    // (self.taskInfoByTaskID[@(task.taskIdentifier)] != nil)
189    // because [self.taskInfoByTaskID removeObjectForKey:@(taskInfo.task.taskIdentifier)]
190    // is called in URLSession:task:didCompleteWithError:.
191    JAHPQNSURLSessionDemuxTaskInfo *    result;
192
193    @synchronized (self) {
194        result = self.taskInfoByTaskID[@(task.taskIdentifier)];
195    }
196    return result;
197}
198
199- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task willPerformHTTPRedirection:(NSHTTPURLResponse *)response newRequest:(NSURLRequest *)newRequest completionHandler:(void (^)(NSURLRequest *))completionHandler
200{
201    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
202
203    taskInfo = [self taskInfoForTask:task];
204    if (taskInfo && [taskInfo.delegate respondsToSelector:@selector(URLSession:task:willPerformHTTPRedirection:newRequest:completionHandler:)]) {
205        [taskInfo performBlock:^{
206            [taskInfo.delegate URLSession:session task:task willPerformHTTPRedirection:response newRequest:newRequest completionHandler:completionHandler];
207        }];
208    } else {
209        completionHandler(newRequest);
210    }
211}
212
213- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler
214{
215    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
216
217    taskInfo = [self taskInfoForTask:task];
218    if (taskInfo && [taskInfo.delegate respondsToSelector:@selector(URLSession:task:didReceiveChallenge:completionHandler:)]) {
219        [taskInfo performBlock:^{
220            [taskInfo.delegate URLSession:session task:task didReceiveChallenge:challenge completionHandler:completionHandler];
221        }];
222    } else {
223        completionHandler(NSURLSessionAuthChallengePerformDefaultHandling, nil);
224    }
225}
226
227- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task needNewBodyStream:(void (^)(NSInputStream *bodyStream))completionHandler
228{
229    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
230
231    taskInfo = [self taskInfoForTask:task];
232    if (taskInfo && [taskInfo.delegate respondsToSelector:@selector(URLSession:task:needNewBodyStream:)]) {
233        [taskInfo performBlock:^{
234            [taskInfo.delegate URLSession:session task:task needNewBodyStream:completionHandler];
235        }];
236    } else {
237        completionHandler(nil);
238    }
239}
240
241- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didSendBodyData:(int64_t)bytesSent totalBytesSent:(int64_t)totalBytesSent totalBytesExpectedToSend:(int64_t)totalBytesExpectedToSend
242{
243    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
244
245    taskInfo = [self taskInfoForTask:task];
246    if (taskInfo && [taskInfo.delegate respondsToSelector:@selector(URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:)]) {
247        [taskInfo performBlock:^{
248            [taskInfo.delegate URLSession:session task:task didSendBodyData:bytesSent totalBytesSent:totalBytesSent totalBytesExpectedToSend:totalBytesExpectedToSend];
249        }];
250    }
251}
252
253- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
254{
255    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
256
257    taskInfo = [self taskInfoForTask:task];
258
259    // This is our last delegate callback so we remove our task info record.
260
261    @synchronized (self) {
262        [self.taskInfoByTaskID removeObjectForKey:@(taskInfo.task.taskIdentifier)];
263    }
264
265    // Call the delegate if required.  In that case we invalidate the task info on the client thread
266    // after calling the delegate, otherwise the client thread side of the -performBlock: code can
267    // find itself with an invalidated task info.
268
269    if ([taskInfo.delegate respondsToSelector:@selector(URLSession:task:didCompleteWithError:)]) {
270        [taskInfo performBlock:^{
271            [taskInfo.delegate URLSession:session task:task didCompleteWithError:error];
272            [taskInfo invalidate];
273        }];
274    } else {
275        [taskInfo invalidate];
276    }
277}
278
279- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler
280{
281    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
282
283    taskInfo = [self taskInfoForTask:dataTask];
284    if (taskInfo && [taskInfo.delegate respondsToSelector:@selector(URLSession:dataTask:didReceiveResponse:completionHandler:)]) {
285        [taskInfo performBlock:^{
286            [taskInfo.delegate URLSession:session dataTask:dataTask didReceiveResponse:response completionHandler:completionHandler];
287        }];
288    } else {
289        completionHandler(NSURLSessionResponseAllow);
290    }
291}
292
293- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didBecomeDownloadTask:(NSURLSessionDownloadTask *)downloadTask
294{
295    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
296
297    taskInfo = [self taskInfoForTask:dataTask];
298    if (taskInfo && [taskInfo.delegate respondsToSelector:@selector(URLSession:dataTask:didBecomeDownloadTask:)]) {
299        [taskInfo performBlock:^{
300            [taskInfo.delegate URLSession:session dataTask:dataTask didBecomeDownloadTask:downloadTask];
301        }];
302    }
303}
304
305- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data
306{
307    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
308
309    taskInfo = [self taskInfoForTask:dataTask];
310    if (taskInfo && [taskInfo.delegate respondsToSelector:@selector(URLSession:dataTask:didReceiveData:)]) {
311        [taskInfo performBlock:^{
312            [taskInfo.delegate URLSession:session dataTask:dataTask didReceiveData:data];
313        }];
314    }
315}
316
317- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask willCacheResponse:(NSCachedURLResponse *)proposedResponse completionHandler:(void (^)(NSCachedURLResponse *cachedResponse))completionHandler
318{
319    JAHPQNSURLSessionDemuxTaskInfo *    taskInfo;
320
321    taskInfo = [self taskInfoForTask:dataTask];
322    if (taskInfo && [taskInfo.delegate respondsToSelector:@selector(URLSession:dataTask:willCacheResponse:completionHandler:)]) {
323        [taskInfo performBlock:^{
324            [taskInfo.delegate URLSession:session dataTask:dataTask willCacheResponse:proposedResponse completionHandler:completionHandler];
325        }];
326    } else {
327        completionHandler(proposedResponse);
328    }
329}
330
331@end
332
333