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#import "platform/background_downloader_ios.h"
#include "platform/downloader_utils.hpp"
@interface TaskInfo : NSObject
@property(nonatomic, strong) NSURLSessionTask *task;
@property(nonatomic, copy) DownloadCompleteBlock completion;
@property(nonatomic, copy) DownloadProgressBlock progress;
- (instancetype)initWithTask:(NSURLSessionTask *)task
completion:(DownloadCompleteBlock)completion
progress:(DownloadProgressBlock)progress;
@end
@implementation TaskInfo
- (instancetype)initWithTask:(NSURLSessionTask *)task
completion:(DownloadCompleteBlock)completion
progress:(DownloadProgressBlock)progress {
self = [super init];
if (self) {
_task = task;
_completion = completion;
_progress = progress;
}
return self;
}
@end
@interface MapFileSaveStrategy : NSObject
- (NSURL *)getLocationForWebUrl:(NSURL *)webUrl;
@end
@implementation MapFileSaveStrategy
- (NSURL *)getLocationForWebUrl:(NSURL *)webUrl {
NSString *path = @(downloader::GetFilePathByUrl(webUrl.path.UTF8String).c_str());
return [NSURL fileURLWithPath:path];
}
@end
@interface BackgroundDownloader () <NSURLSessionDownloadDelegate>
@property(nonatomic, strong) NSURLSession *session;
@property(nonatomic, strong) NSMutableDictionary *tasks;
@property(nonatomic, strong) NSMutableDictionary *restoredTasks;
@property(nonatomic, strong) NSHashTable *subscribers;
@property(nonatomic, strong) MapFileSaveStrategy *saveStrategy;
@end
@implementation BackgroundDownloader
+ (BackgroundDownloader *)sharedBackgroundMapDownloader {
static dispatch_once_t dispatchOnce;
static BackgroundDownloader *backgroundDownloader;
dispatch_once(&dispatchOnce, ^{
MapFileSaveStrategy *mapFileSaveStrategy = [[MapFileSaveStrategy alloc] init];
backgroundDownloader = [[BackgroundDownloader alloc] initWithSessionName:@"background_map_downloader"
saveStrategy:mapFileSaveStrategy];
});
return backgroundDownloader;
}
- (instancetype)initWithSessionName:(NSString *)name saveStrategy:(MapFileSaveStrategy *)saveStrategy {
self = [super init];
if (self) {
NSURLSessionConfiguration *configuration =
[NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:name];
[configuration setSessionSendsLaunchEvents:YES];
_session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:nil];
_tasks = [NSMutableDictionary dictionary];
_subscribers = [NSHashTable weakObjectsHashTable];
_saveStrategy = saveStrategy;
_restoredTasks = [NSMutableDictionary dictionary];
[_session getAllTasksWithCompletionHandler:^(NSArray<__kindof NSURLSessionTask *> *_Nonnull downloadTasks) {
dispatch_async(dispatch_get_main_queue(), ^{
for (NSURLSessionTask *downloadTask in downloadTasks) {
TaskInfo *info = [self.tasks objectForKey:@(downloadTask.taskIdentifier)];
if (info)
continue;
NSString *urlString = downloadTask.currentRequest.URL.path;
BOOL isTaskReplaced = NO;
/// Replacing task with another one which was added into queue earlier (on previous application session).
for (TaskInfo *info in self.tasks) {
if (![info.task.currentRequest.URL.path isEqualToString:urlString])
continue;
TaskInfo *newInfo = [[TaskInfo alloc] initWithTask:downloadTask
completion:info.completion
progress:info.progress];
[self.tasks setObject:newInfo forKey:@(downloadTask.taskIdentifier)];
[info.task cancel];
[self.tasks removeObjectForKey:@(info.task.taskIdentifier)];
isTaskReplaced = YES;
break;
}
if (!isTaskReplaced)
[self.restoredTasks setObject:downloadTask forKey:urlString];
}
});
}];
}
return self;
}
- (void)subscribe:(id<BackgroundDownloaderSubscriber>)subscriber {
[self.subscribers addObject:subscriber];
}
- (void)unsubscribe:(id<BackgroundDownloaderSubscriber>)subscriber {
[self.subscribers removeObject:subscriber];
}
- (NSUInteger)downloadWithUrl:(NSURL *)url
completion:(DownloadCompleteBlock)completion
progress:(DownloadProgressBlock)progress {
NSUInteger taskIdentifier;
NSURLSessionTask *restoredTask = [self.restoredTasks objectForKey:url.path];
if (restoredTask) {
TaskInfo *info = [[TaskInfo alloc] initWithTask:restoredTask completion:completion progress:progress];
[self.tasks setObject:info forKey:@(restoredTask.taskIdentifier)];
[self.restoredTasks removeObjectForKey:url.path];
taskIdentifier = restoredTask.taskIdentifier;
} else {
NSURLSessionTask *task = [self.session downloadTaskWithURL:url];
TaskInfo *info = [[TaskInfo alloc] initWithTask:task completion:completion progress:progress];
[self.tasks setObject:info forKey:@(task.taskIdentifier)];
[task resume];
taskIdentifier = task.taskIdentifier;
}
if ([self.tasks count] == 1) {
for (id<BackgroundDownloaderSubscriber> subscriber in self.subscribers)
[subscriber didStartDownloading];
}
return taskIdentifier;
}
- (void)cancelTaskWithIdentifier:(NSUInteger)taskIdentifier {
BOOL needNotify = [self.tasks count] > 0;
TaskInfo *info = self.tasks[@(taskIdentifier)];
if (info) {
[info.task cancel];
[self.tasks removeObjectForKey:@(taskIdentifier)];
} else {
for (NSString *key in self.restoredTasks) {
NSURLSessionTask *restoredTask = self.restoredTasks[key];
if (restoredTask.taskIdentifier == taskIdentifier) {
[restoredTask cancel];
[self.restoredTasks removeObjectForKey:key];
break;
}
}
}
if (needNotify && [self.tasks count] == 0) {
for (id<BackgroundDownloaderSubscriber> subscriber in self.subscribers)
[subscriber didFinishDownloading];
}
}
- (void)clear {
BOOL needNotify = [self.tasks count] > 0;
for (TaskInfo *info in self.tasks) {
[info.task cancel];
}
for (NSURLSessionTask *restoredTask in self.restoredTasks) {
[restoredTask cancel];
}
[self.tasks removeAllObjects];
[self.restoredTasks removeAllObjects];
if (needNotify) {
for (id<BackgroundDownloaderSubscriber> subscriber in self.subscribers)
[subscriber didFinishDownloading];
}
}
#pragma mark - NSURLSessionDownloadDelegate implementation
- (void)finishDownloading:(NSURLSessionTask *)downloadTask error:(nullable NSError *)error {
[self.restoredTasks removeObjectForKey:downloadTask.currentRequest.URL.path];
TaskInfo *info = [self.tasks objectForKey:@(downloadTask.taskIdentifier)];
if (!info)
return;
info.completion(error);
[self.tasks removeObjectForKey:@(downloadTask.taskIdentifier)];
if ([self.tasks count] == 0) {
for (id<BackgroundDownloaderSubscriber> subscriber in self.subscribers)
[subscriber didFinishDownloading];
}
}
- (void)URLSession:(NSURLSession *)session
downloadTask:(NSURLSessionDownloadTask *)downloadTask
didFinishDownloadingToURL:(NSURL *)location {
NSURL *destinationUrl = [self.saveStrategy getLocationForWebUrl:downloadTask.currentRequest.URL];
NSError *error;
[[NSFileManager defaultManager] moveItemAtURL:location.filePathURL toURL:destinationUrl error:&error];
dispatch_async(dispatch_get_main_queue(), ^{
[self finishDownloading:downloadTask error:error];
});
}
- (void)URLSession:(NSURLSession *)session
downloadTask:(NSURLSessionDownloadTask *)downloadTask
didWriteData:(int64_t)bytesWritten
totalBytesWritten:(int64_t)totalBytesWritten
totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite {
dispatch_async(dispatch_get_main_queue(), ^{
TaskInfo *info = [self.tasks objectForKey:@(downloadTask.taskIdentifier)];
if (!info)
return;
info.progress(totalBytesWritten, totalBytesExpectedToWrite);
});
}
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)downloadTask didCompleteWithError:(NSError *)error {
dispatch_async(dispatch_get_main_queue(), ^{
if (error && error.code != NSURLErrorCancelled)
[self finishDownloading:downloadTask error:error];
});
}
- (void)URLSessionDidFinishEventsForBackgroundURLSession:(NSURLSession *)session {
dispatch_async(dispatch_get_main_queue(), ^{
if (self.backgroundCompletionHandler != nil)
self.backgroundCompletionHandler();
});
}
@end
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