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/*
* This file is part of the SDWebImage package.
* (c) Olivier Poitrey <rs@dailymotion.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
#import "SDWebImageDownloaderOperation.h"
#import "SDWebImageError.h"
#import "SDInternalMacros.h"
// iOS 8 Foundation.framework extern these symbol but the define is in CFNetwork.framework. We just fix this without import CFNetwork.framework
#if (__IPHONE_OS_VERSION_MIN_REQUIRED && __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_9_0)
const float NSURLSessionTaskPriorityHigh = 0.75;
const float NSURLSessionTaskPriorityDefault = 0.5;
const float NSURLSessionTaskPriorityLow = 0.25;
#endif
static NSString *const kProgressCallbackKey = @"progress";
static NSString *const kCompletedCallbackKey = @"completed";
typedef NSMutableDictionary<NSString *, id> SDCallbacksDictionary;
@interface SDWebImageDownloaderOperation ()
@property (strong, nonatomic, nonnull) NSMutableArray<SDCallbacksDictionary *> *callbackBlocks;
@property (assign, nonatomic, readwrite) SDWebImageDownloaderOptions options;
@property (copy, nonatomic, readwrite, nullable) SDWebImageContext *context;
@property (assign, nonatomic, getter = isExecuting) BOOL executing;
@property (assign, nonatomic, getter = isFinished) BOOL finished;
@property (strong, nonatomic, nullable) NSMutableData *imageData;
@property (copy, nonatomic, nullable) NSData *cachedData; // for `SDWebImageDownloaderIgnoreCachedResponse`
@property (assign, nonatomic) NSUInteger expectedSize; // may be 0
@property (assign, nonatomic) NSUInteger receivedSize;
@property (strong, nonatomic, nullable, readwrite) NSURLResponse *response;
@property (strong, nonatomic, nullable) NSError *responseError;
@property (assign, nonatomic) double previousProgress; // previous progress percent
// 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, nullable) NSURLSession *unownedSession;
// This is set if we're using not using an injected NSURLSession. We're responsible of invalidating this one
@property (strong, nonatomic, nullable) NSURLSession *ownedSession;
@property (strong, nonatomic, readwrite, nullable) NSURLSessionTask *dataTask;
@property (strong, nonatomic, nonnull) dispatch_semaphore_t callbacksLock; // a lock to keep the access to `callbackBlocks` thread-safe
@property (strong, nonatomic, nonnull) dispatch_queue_t coderQueue; // the queue to do image decoding
#if SD_UIKIT
@property (assign, nonatomic) UIBackgroundTaskIdentifier backgroundTaskId;
#endif
@end
@implementation SDWebImageDownloaderOperation
@synthesize executing = _executing;
@synthesize finished = _finished;
- (nonnull instancetype)init {
return [self initWithRequest:nil inSession:nil options:0];
}
- (instancetype)initWithRequest:(NSURLRequest *)request inSession:(NSURLSession *)session options:(SDWebImageDownloaderOptions)options {
return [self initWithRequest:request inSession:session options:options context:nil];
}
- (nonnull instancetype)initWithRequest:(nullable NSURLRequest *)request
inSession:(nullable NSURLSession *)session
options:(SDWebImageDownloaderOptions)options
context:(nullable SDWebImageContext *)context {
if ((self = [super init])) {
_request = [request copy];
_options = options;
_context = [context copy];
_callbackBlocks = [NSMutableArray new];
_executing = NO;
_finished = NO;
_expectedSize = 0;
_unownedSession = session;
_callbacksLock = dispatch_semaphore_create(1);
_coderQueue = dispatch_queue_create("com.hackemist.SDWebImageDownloaderOperationCoderQueue", DISPATCH_QUEUE_SERIAL);
#if SD_UIKIT
_backgroundTaskId = UIBackgroundTaskInvalid;
#endif
}
return self;
}
- (nullable id)addHandlersForProgress:(nullable SDWebImageDownloaderProgressBlock)progressBlock
completed:(nullable SDWebImageDownloaderCompletedBlock)completedBlock {
SDCallbacksDictionary *callbacks = [NSMutableDictionary new];
if (progressBlock) callbacks[kProgressCallbackKey] = [progressBlock copy];
if (completedBlock) callbacks[kCompletedCallbackKey] = [completedBlock copy];
SD_LOCK(self.callbacksLock);
[self.callbackBlocks addObject:callbacks];
SD_UNLOCK(self.callbacksLock);
return callbacks;
}
- (nullable NSArray<id> *)callbacksForKey:(NSString *)key {
SD_LOCK(self.callbacksLock);
NSMutableArray<id> *callbacks = [[self.callbackBlocks valueForKey:key] mutableCopy];
SD_UNLOCK(self.callbacksLock);
// We need to remove [NSNull null] because there might not always be a progress block for each callback
[callbacks removeObjectIdenticalTo:[NSNull null]];
return [callbacks copy]; // strip mutability here
}
- (BOOL)cancel:(nullable id)token {
BOOL shouldCancel = NO;
SD_LOCK(self.callbacksLock);
[self.callbackBlocks removeObjectIdenticalTo:token];
if (self.callbackBlocks.count == 0) {
shouldCancel = YES;
}
SD_UNLOCK(self.callbacksLock);
if (shouldCancel) {
[self cancel];
}
return shouldCancel;
}
- (void)start {
@synchronized (self) {
if (self.isCancelled) {
self.finished = YES;
[self reset];
return;
}
#if SD_UIKIT
Class UIApplicationClass = NSClassFromString(@"UIApplication");
BOOL hasApplication = UIApplicationClass && [UIApplicationClass respondsToSelector:@selector(sharedApplication)];
if (hasApplication && [self shouldContinueWhenAppEntersBackground]) {
__weak typeof(self) wself = self;
UIApplication * app = [UIApplicationClass performSelector:@selector(sharedApplication)];
self.backgroundTaskId = [app beginBackgroundTaskWithExpirationHandler:^{
[wself cancel];
}];
}
#endif
NSURLSession *session = self.unownedSession;
if (!session) {
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.
*/
session = [NSURLSession sessionWithConfiguration:sessionConfig
delegate:self
delegateQueue:nil];
self.ownedSession = session;
}
if (self.options & SDWebImageDownloaderIgnoreCachedResponse) {
// Grab the cached data for later check
NSURLCache *URLCache = session.configuration.URLCache;
if (!URLCache) {
URLCache = [NSURLCache sharedURLCache];
}
NSCachedURLResponse *cachedResponse;
// NSURLCache's `cachedResponseForRequest:` is not thread-safe, see https://developer.apple.com/documentation/foundation/nsurlcache#2317483
@synchronized (URLCache) {
cachedResponse = [URLCache cachedResponseForRequest:self.request];
}
if (cachedResponse) {
self.cachedData = cachedResponse.data;
}
}
self.dataTask = [session dataTaskWithRequest:self.request];
self.executing = YES;
}
if (self.dataTask) {
if (self.options & SDWebImageDownloaderHighPriority) {
self.dataTask.priority = NSURLSessionTaskPriorityHigh;
} else if (self.options & SDWebImageDownloaderLowPriority) {
self.dataTask.priority = NSURLSessionTaskPriorityLow;
}
[self.dataTask resume];
for (SDWebImageDownloaderProgressBlock progressBlock in [self callbacksForKey:kProgressCallbackKey]) {
progressBlock(0, NSURLResponseUnknownLength, self.request.URL);
}
__block typeof(self) strongSelf = self;
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStartNotification object:strongSelf];
});
} else {
[self callCompletionBlocksWithError:[NSError errorWithDomain:SDWebImageErrorDomain code:SDWebImageErrorInvalidDownloadOperation userInfo:@{NSLocalizedDescriptionKey : @"Task can't be initialized"}]];
[self done];
}
}
- (void)cancel {
@synchronized (self) {
[self cancelInternal];
}
}
- (void)cancelInternal {
if (self.isFinished) return;
[super cancel];
if (self.dataTask) {
[self.dataTask cancel];
__block typeof(self) strongSelf = self;
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStopNotification object:strongSelf];
});
// As we cancelled the task, its callback won't be called and thus won't
// maintain the isFinished and isExecuting flags.
if (self.isExecuting) self.executing = NO;
if (!self.isFinished) self.finished = YES;
}
[self reset];
}
- (void)done {
self.finished = YES;
self.executing = NO;
[self reset];
}
- (void)reset {
SD_LOCK(self.callbacksLock);
[self.callbackBlocks removeAllObjects];
SD_UNLOCK(self.callbacksLock);
@synchronized (self) {
self.dataTask = nil;
if (self.ownedSession) {
[self.ownedSession invalidateAndCancel];
self.ownedSession = nil;
}
#if SD_UIKIT
if (self.backgroundTaskId != UIBackgroundTaskInvalid) {
// If backgroundTaskId != UIBackgroundTaskInvalid, sharedApplication is always exist
UIApplication * app = [UIApplication performSelector:@selector(sharedApplication)];
[app endBackgroundTask:self.backgroundTaskId];
self.backgroundTaskId = UIBackgroundTaskInvalid;
}
#endif
}
}
- (void)setFinished:(BOOL)finished {
[self willChangeValueForKey:@"isFinished"];
_finished = finished;
[self didChangeValueForKey:@"isFinished"];
}
- (void)setExecuting:(BOOL)executing {
[self willChangeValueForKey:@"isExecuting"];
_executing = executing;
[self didChangeValueForKey:@"isExecuting"];
}
- (BOOL)isConcurrent {
return YES;
}
#pragma mark NSURLSessionDataDelegate
- (void)URLSession:(NSURLSession *)session
dataTask:(NSURLSessionDataTask *)dataTask
didReceiveResponse:(NSURLResponse *)response
completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler {
NSURLSessionResponseDisposition disposition = NSURLSessionResponseAllow;
NSInteger expected = (NSInteger)response.expectedContentLength;
expected = expected > 0 ? expected : 0;
self.expectedSize = expected;
self.response = response;
NSInteger statusCode = [response respondsToSelector:@selector(statusCode)] ? ((NSHTTPURLResponse *)response).statusCode : 200;
BOOL valid = statusCode >= 200 && statusCode < 400;
if (!valid) {
self.responseError = [NSError errorWithDomain:SDWebImageErrorDomain code:SDWebImageErrorInvalidDownloadStatusCode userInfo:@{SDWebImageErrorDownloadStatusCodeKey : @(statusCode)}];
}
//'304 Not Modified' is an exceptional one
//URLSession current behavior will return 200 status code when the server respond 304 and URLCache hit. But this is not a standard behavior and we just add a check
if (statusCode == 304 && !self.cachedData) {
valid = NO;
self.responseError = [NSError errorWithDomain:SDWebImageErrorDomain code:SDWebImageErrorCacheNotModified userInfo:nil];
}
if (valid) {
for (SDWebImageDownloaderProgressBlock progressBlock in [self callbacksForKey:kProgressCallbackKey]) {
progressBlock(0, expected, self.request.URL);
}
} else {
// Status code invalid and marked as cancelled. Do not call `[self.dataTask cancel]` which may mass up URLSession life cycle
disposition = NSURLSessionResponseCancel;
}
__block typeof(self) strongSelf = self;
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadReceiveResponseNotification object:strongSelf];
});
if (completionHandler) {
completionHandler(disposition);
}
}
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
if (!self.imageData) {
self.imageData = [[NSMutableData alloc] initWithCapacity:self.expectedSize];
}
[self.imageData appendData:data];
self.receivedSize = self.imageData.length;
if (self.expectedSize == 0) {
// Unknown expectedSize, immediately call progressBlock and return
for (SDWebImageDownloaderProgressBlock progressBlock in [self callbacksForKey:kProgressCallbackKey]) {
progressBlock(self.receivedSize, self.expectedSize, self.request.URL);
}
return;
}
// Get the finish status
BOOL finished = (self.receivedSize >= self.expectedSize);
// Get the current progress
double currentProgress = (double)self.receivedSize / (double)self.expectedSize;
double previousProgress = self.previousProgress;
double progressInterval = currentProgress - previousProgress;
// Check if we need callback progress
if (!finished && (progressInterval < self.minimumProgressInterval)) {
return;
}
self.previousProgress = currentProgress;
if (self.options & SDWebImageDownloaderProgressiveLoad) {
// Get the image data
NSData *imageData = [self.imageData copy];
// progressive decode the image in coder queue
dispatch_async(self.coderQueue, ^{
@autoreleasepool {
UIImage *image = SDImageLoaderDecodeProgressiveImageData(imageData, self.request.URL, finished, self, [[self class] imageOptionsFromDownloaderOptions:self.options], self.context);
if (image) {
// We do not keep the progressive decoding image even when `finished`=YES. Because they are for view rendering but not take full function from downloader options. And some coders implementation may not keep consistent between progressive decoding and normal decoding.
[self callCompletionBlocksWithImage:image imageData:nil error:nil finished:NO];
}
}
});
}
for (SDWebImageDownloaderProgressBlock progressBlock in [self callbacksForKey:kProgressCallbackKey]) {
progressBlock(self.receivedSize, self.expectedSize, self.request.URL);
}
}
- (void)URLSession:(NSURLSession *)session
dataTask:(NSURLSessionDataTask *)dataTask
willCacheResponse:(NSCachedURLResponse *)proposedResponse
completionHandler:(void (^)(NSCachedURLResponse *cachedResponse))completionHandler {
NSCachedURLResponse *cachedResponse = proposedResponse;
if (!(self.options & SDWebImageDownloaderUseNSURLCache)) {
// Prevents caching of responses
cachedResponse = nil;
}
if (completionHandler) {
completionHandler(cachedResponse);
}
}
#pragma mark NSURLSessionTaskDelegate
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
@synchronized(self) {
self.dataTask = nil;
__block typeof(self) strongSelf = self;
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadStopNotification object:strongSelf];
if (!error) {
[[NSNotificationCenter defaultCenter] postNotificationName:SDWebImageDownloadFinishNotification object:strongSelf];
}
});
}
// make sure to call `[self done]` to mark operation as finished
if (error) {
// custom error instead of URLSession error
if (self.responseError) {
error = self.responseError;
}
[self callCompletionBlocksWithError:error];
[self done];
} else {
if ([self callbacksForKey:kCompletedCallbackKey].count > 0) {
NSData *imageData = [self.imageData copy];
self.imageData = nil;
if (imageData) {
/** if you specified to only use cached data via `SDWebImageDownloaderIgnoreCachedResponse`,
* then we should check if the cached data is equal to image data
*/
if (self.options & SDWebImageDownloaderIgnoreCachedResponse && [self.cachedData isEqualToData:imageData]) {
self.responseError = [NSError errorWithDomain:SDWebImageErrorDomain code:SDWebImageErrorCacheNotModified userInfo:nil];
// call completion block with not modified error
[self callCompletionBlocksWithError:self.responseError];
[self done];
} else {
// decode the image in coder queue
dispatch_async(self.coderQueue, ^{
@autoreleasepool {
UIImage *image = SDImageLoaderDecodeImageData(imageData, self.request.URL, [[self class] imageOptionsFromDownloaderOptions:self.options], self.context);
CGSize imageSize = image.size;
if (imageSize.width == 0 || imageSize.height == 0) {
[self callCompletionBlocksWithError:[NSError errorWithDomain:SDWebImageErrorDomain code:SDWebImageErrorBadImageData userInfo:@{NSLocalizedDescriptionKey : @"Downloaded image has 0 pixels"}]];
} else {
[self callCompletionBlocksWithImage:image imageData:imageData error:nil finished:YES];
}
[self done];
}
});
}
} else {
[self callCompletionBlocksWithError:[NSError errorWithDomain:SDWebImageErrorDomain code:SDWebImageErrorBadImageData userInfo:@{NSLocalizedDescriptionKey : @"Image data is nil"}]];
[self done];
}
} else {
[self done];
}
}
}
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler {
NSURLSessionAuthChallengeDisposition disposition = NSURLSessionAuthChallengePerformDefaultHandling;
__block NSURLCredential *credential = nil;
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
if (!(self.options & SDWebImageDownloaderAllowInvalidSSLCertificates)) {
disposition = NSURLSessionAuthChallengePerformDefaultHandling;
} else {
credential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust];
disposition = NSURLSessionAuthChallengeUseCredential;
}
} else {
if (challenge.previousFailureCount == 0) {
if (self.credential) {
credential = self.credential;
disposition = NSURLSessionAuthChallengeUseCredential;
} else {
disposition = NSURLSessionAuthChallengeCancelAuthenticationChallenge;
}
} else {
disposition = NSURLSessionAuthChallengeCancelAuthenticationChallenge;
}
}
if (completionHandler) {
completionHandler(disposition, credential);
}
}
#pragma mark Helper methods
+ (SDWebImageOptions)imageOptionsFromDownloaderOptions:(SDWebImageDownloaderOptions)downloadOptions {
SDWebImageOptions options = 0;
if (downloadOptions & SDWebImageDownloaderScaleDownLargeImages) options |= SDWebImageScaleDownLargeImages;
if (downloadOptions & SDWebImageDownloaderDecodeFirstFrameOnly) options |= SDWebImageDecodeFirstFrameOnly;
if (downloadOptions & SDWebImageDownloaderPreloadAllFrames) options |= SDWebImagePreloadAllFrames;
if (downloadOptions & SDWebImageDownloaderAvoidDecodeImage) options |= SDWebImageAvoidDecodeImage;
return options;
}
- (BOOL)shouldContinueWhenAppEntersBackground {
return self.options & SDWebImageDownloaderContinueInBackground;
}
- (void)callCompletionBlocksWithError:(nullable NSError *)error {
[self callCompletionBlocksWithImage:nil imageData:nil error:error finished:YES];
}
- (void)callCompletionBlocksWithImage:(nullable UIImage *)image
imageData:(nullable NSData *)imageData
error:(nullable NSError *)error
finished:(BOOL)finished {
NSArray<id> *completionBlocks = [self callbacksForKey:kCompletedCallbackKey];
dispatch_main_async_safe(^{
for (SDWebImageDownloaderCompletedBlock completedBlock in completionBlocks) {
completedBlock(image, imageData, error, finished);
}
});
}
@end
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