path: root/SmartDeviceLink/public/SDLFileManager.m

//
//  SDLFileManager.m
//  SmartDeviceLink-iOS
//
//  Created by Joel Fischer on 10/14/15.
//  Copyright © 2015 smartdevicelink. All rights reserved.
//

#import "SDLFileManager.h"

#import "SDLConnectionManagerType.h"
#import "SDLLogMacros.h"
#import "SDLDeleteFileOperation.h"
#import "SDLError.h"
#import "SDLErrorConstants.h"
#import "SDLFile.h"
#import "SDLFileManagerConfiguration.h"
#import "SDLFileWrapper.h"
#import "SDLGlobals.h"
#import "SDLListFilesOperation.h"
#import "SDLManager.h"
#import "SDLNotificationConstants.h"
#import "SDLPutFile.h"
#import "SDLStateMachine.h"
#import "SDLUploadFileOperation.h"
#import "SDLVersion.h"


NS_ASSUME_NONNULL_BEGIN

typedef NSString SDLFileManagerState;
SDLFileManagerState *const SDLFileManagerStateShutdown = @"Shutdown";
SDLFileManagerState *const SDLFileManagerStateFetchingInitialList = @"FetchingInitialList";
SDLFileManagerState *const SDLFileManagerStateReady = @"Ready";
SDLFileManagerState *const SDLFileManagerStateStartupError = @"StartupError";


#pragma mark - SDLFileManager class

@interface SDLFileManager ()

@property (weak, nonatomic) id<SDLConnectionManagerType> connectionManager;

// Remote state
@property (strong, nonatomic) NSMutableSet<SDLFileName *> *mutableRemoteFileNames;
@property (assign, nonatomic, readwrite) NSUInteger bytesAvailable;

// Local state
@property (strong, nonatomic) NSOperationQueue *transactionQueue;
@property (strong, nonatomic) NSMutableSet<SDLFileName *> *uploadedEphemeralFileNames;
@property (strong, nonatomic) SDLStateMachine *stateMachine;
@property (copy, nonatomic, nullable) SDLFileManagerStartupCompletionHandler startupCompletionHandler;

@property (strong, nonatomic) NSMutableDictionary<SDLFileName *, NSNumber<SDLUInt> *> *failedFileUploadsCount;
@property (assign, nonatomic) NSUInteger maxFileUploadAttempts;
@property (assign, nonatomic) NSUInteger maxArtworkUploadAttempts;

@end

#pragma mark Constants

@implementation SDLFileManager

#pragma mark - Lifecycle

- (instancetype)initWithConnectionManager:(id<SDLConnectionManagerType>)manager configuration:(SDLFileManagerConfiguration *)configuration {
    self = [super init];
    if (!self) {
        return nil;
    }

    _connectionManager = manager;
    _bytesAvailable = 0;

    _mutableRemoteFileNames = [NSMutableSet set];
    _transactionQueue = [[NSOperationQueue alloc] init];
    _transactionQueue.name = @"com.sdl.fileManager.transactionQueue";
    _transactionQueue.underlyingQueue = [SDLGlobals sharedGlobals].sdlProcessingQueue;
    _transactionQueue.maxConcurrentOperationCount = 1;
    _uploadedEphemeralFileNames = [[NSMutableSet<SDLFileName *> alloc] init];

    _stateMachine = [[SDLStateMachine alloc] initWithTarget:self initialState:SDLFileManagerStateShutdown states:[self.class sdl_stateTransitionDictionary]];

    _failedFileUploadsCount = [NSMutableDictionary dictionary];
    _maxFileUploadAttempts = configuration.fileRetryCount + 1;
    _maxArtworkUploadAttempts = configuration.artworkRetryCount + 1;

    return self;
}

#pragma mark - Setup / Shutdown

- (void)startWithCompletionHandler:(nullable SDLFileManagerStartupCompletionHandler)handler {
    if ([self.currentState isEqualToString:SDLFileManagerStateShutdown]) {
        self.startupCompletionHandler = handler;
        [self.stateMachine transitionToState:SDLFileManagerStateFetchingInitialList];
    } else {
        // If we already started, just tell the handler we're started.
        handler(YES, nil);
    }
}

- (void)stop {
    [self.stateMachine transitionToState:SDLFileManagerStateShutdown];
}

- (void)dealloc {
    if (self.currentState != SDLFileManagerStateShutdown) {
        [self.stateMachine transitionToState:SDLFileManagerStateShutdown];
    }
}

#pragma mark - Getters

- (NSSet<SDLFileName *> *)remoteFileNames {
    return [NSSet setWithSet:self.mutableRemoteFileNames];
}

- (NSString *)currentState {
    return self.stateMachine.currentState;
}

- (NSArray<__kindof NSOperation *> *)pendingTransactions {
    return self.transactionQueue.operations;
}

- (BOOL)suspended {
    return self.transactionQueue.suspended;
}


#pragma mark Setters

- (void)setSuspended:(BOOL)suspended {
    self.transactionQueue.suspended = suspended;
}


#pragma mark - State

+ (NSDictionary<SDLState *, SDLAllowableStateTransitions *> *)sdl_stateTransitionDictionary {
    return @{
             SDLFileManagerStateShutdown: @[SDLFileManagerStateFetchingInitialList],
             SDLFileManagerStateFetchingInitialList: @[SDLFileManagerStateShutdown, SDLFileManagerStateReady, SDLFileManagerStateStartupError],
             SDLFileManagerStateReady: @[SDLFileManagerStateShutdown],
             SDLFileManagerStateStartupError: @[SDLFileManagerStateShutdown]
             };
}

- (void)didEnterStateStartupError {
    if (self.startupCompletionHandler != nil) {
        self.startupCompletionHandler(NO, [NSError sdl_fileManager_unableToStartError]);
        self.startupCompletionHandler = nil;
    }
}

- (void)didEnterStateShutdown {
    [self.transactionQueue cancelAllOperations];
    [self.mutableRemoteFileNames removeAllObjects];
    [self.class sdl_clearTemporaryFileDirectory];
    self.bytesAvailable = 0;

    // Clear the failed uploads tracking so failed files can be uploaded again when a new connection has been established with Core
    _failedFileUploadsCount = [NSMutableDictionary dictionary];

    if (self.startupCompletionHandler != nil) {
        self.startupCompletionHandler(NO, [NSError sdl_fileManager_unableToStartError]);
        self.startupCompletionHandler = nil;
    }
}

- (void)didEnterStateFetchingInitialList {
    __weak typeof(self) weakSelf = self;
    [self sdl_listRemoteFilesWithCompletionHandler:^(BOOL success, NSUInteger bytesAvailable, NSArray<NSString *> *_Nonnull fileNames, NSError *_Nullable error) {
        // If we've already shut down by this point, just stay in the shutdown state
        if ([weakSelf.stateMachine.currentState isEqualToString:SDLFileManagerStateShutdown]) {
            BLOCK_RETURN;
        }

        // If there was an error, we'll pass the error to the startup handler and cancel out
        if (error != nil) {
            if ([error.userInfo[@"resultCode"] isEqualToEnum:SDLResultDisallowed]) {
                // HAX: In the case we are DISALLOWED we still want to transition to a ready state. Some head units return DISALLOWED for this RPC but otherwise work.
                SDLLogW(@"ListFiles is disallowed. Certain file manager APIs may not work properly.");
                [weakSelf.stateMachine transitionToState:SDLFileManagerStateReady];
                BLOCK_RETURN;
            } else if ([error.userInfo[@"resultCode"] isEqualToEnum:SDLResultEncryptionNeeded]) {
                // If the module rejects the ListFiles request because it requires that the request be encrypted, we still want to transition to a ready state. Unfortunately, since we do not know what files are on the module already, we may end up doing unnecessary duplicate file uploads.
                SDLLogE(@"ListFiles must be encrypted but was not when the file manager started. We do not know which files have already been uploaded to the module. All files will need to be re-uploaded. Certain file manager APIs may not work properly.");
                [weakSelf.stateMachine transitionToState:SDLFileManagerStateReady];
                BLOCK_RETURN;
            }
            [weakSelf.stateMachine transitionToState:SDLFileManagerStateStartupError];
            BLOCK_RETURN;
        }

        // If no error, make sure we're in the ready state
        [weakSelf.stateMachine transitionToState:SDLFileManagerStateReady];
    }];
}

- (void)didEnterStateReady {
    if (self.startupCompletionHandler != nil) {
        self.startupCompletionHandler(YES, nil);
        self.startupCompletionHandler = nil;
    }
}


#pragma mark - Private Listing Remote Files

- (void)sdl_listRemoteFilesWithCompletionHandler:(SDLFileManagerListFilesCompletionHandler)handler {
    __weak typeof(self) weakSelf = self;
    SDLListFilesOperation *listOperation = [[SDLListFilesOperation alloc] initWithConnectionManager:self.connectionManager completionHandler:^(BOOL success, NSUInteger bytesAvailable, NSArray<NSString *> *_Nonnull fileNames, NSError *_Nullable error) {
        if (error != nil || !success) {
            handler(success, bytesAvailable, fileNames, error);
            BLOCK_RETURN;
        }

        // If there was no error, set our properties and call back to the startup completion handler
        [weakSelf.mutableRemoteFileNames addObjectsFromArray:fileNames];
        weakSelf.bytesAvailable = bytesAvailable;

        handler(success, bytesAvailable, fileNames, error);
    }];

    [self.transactionQueue addOperation:listOperation];
}


#pragma mark - Deleting

- (void)deleteRemoteFileWithName:(SDLFileName *)name completionHandler:(nullable SDLFileManagerDeleteCompletionHandler)handler {
    __weak typeof(self) weakSelf = self;
    SDLDeleteFileOperation *deleteOperation = [[SDLDeleteFileOperation alloc] initWithFileName:name connectionManager:self.connectionManager remoteFileNames:self.remoteFileNames completionHandler:^(BOOL success, NSUInteger bytesAvailable, NSError *_Nullable error) {
        __strong typeof(weakSelf) strongSelf = weakSelf;

        // Mutate self based on the changes
        if (success) {
            strongSelf.bytesAvailable = bytesAvailable;
            [strongSelf.mutableRemoteFileNames removeObject:name];
        }

        if (handler != nil) {
            handler(success, bytesAvailable, error);
        }
    }];

    [self.transactionQueue addOperation:deleteOperation];
}

- (void)deleteRemoteFilesWithNames:(NSArray<SDLFileName *> *)names completionHandler:(nullable SDLFileManagerMultiDeleteCompletionHandler)completionHandler {
    if (names.count == 0) {
        @throw [NSException sdl_missingFilesException];
    }

    NSMutableDictionary *failedDeletes = [[NSMutableDictionary alloc] init];

    dispatch_group_t deleteFilesTask = dispatch_group_create();
    dispatch_group_enter(deleteFilesTask);
    __weak typeof(self) weakself = self;
    for (NSString *name in names) {
        dispatch_group_enter(deleteFilesTask);
        [self deleteRemoteFileWithName:name completionHandler:^(BOOL success, NSUInteger bytesAvailable, NSError * _Nullable error) {
            if (!success) {
                failedDeletes[name] = error;
            }
            dispatch_group_leave(deleteFilesTask);
        }];
    }
    dispatch_group_leave(deleteFilesTask);

    // When all files to be deleted
    dispatch_group_notify(deleteFilesTask, [SDLGlobals sharedGlobals].sdlProcessingQueue, ^{
        if (completionHandler == nil) { return; }
        if (failedDeletes.count > 0) {
            return completionHandler([NSError sdl_fileManager_unableToDelete_ErrorWithUserInfo:failedDeletes]);
        }
        return completionHandler(nil);
    });
}

#pragma mark - Uploading
#pragma mark Files

- (BOOL)hasUploadedFile:(SDLFile *)file {
    // HAX: [#827](https://github.com/smartdevicelink/sdl_ios/issues/827) Older versions of Core had a bug where list files would cache incorrectly.
    if ([[SDLGlobals sharedGlobals].rpcVersion isLessThanVersion:[SDLVersion versionWithMajor:4 minor:4 patch:0]]) {
        if (file.persistent && [self.remoteFileNames containsObject:file.name]) {
            // HAX: If it's a persistent file, the bug won't present itself; just check if it's on the remote system
            return YES;
        } else if (!file.persistent && [self.remoteFileNames containsObject:file.name] && [self.uploadedEphemeralFileNames containsObject:file.name]) {
            // HAX: If it's an ephemeral file, the bug will present itself; check that it's a remote file AND that we've uploaded it this session
            return YES;
        }
    } else if ([self.remoteFileNames containsObject:file.name]) {
        // If not connected to a system where the bug presents itself, we can trust the `remoteFileNames`
        return YES;
    }

    return NO;
}

- (void)uploadFiles:(NSArray<SDLFile *> *)files completionHandler:(nullable SDLFileManagerMultiUploadCompletionHandler)completionHandler {
    [self uploadFiles:files progressHandler:nil completionHandler:completionHandler];
}

- (void)uploadFiles:(NSArray<SDLFile *> *)files progressHandler:(nullable SDLFileManagerMultiUploadProgressHandler)progressHandler completionHandler:(nullable SDLFileManagerMultiUploadCompletionHandler)completionHandler {
    if (files.count == 0) {
        @throw [NSException sdl_missingFilesException];
    }

    NSMutableDictionary *failedUploads = [[NSMutableDictionary alloc] init];
    float totalBytesToUpload = (progressHandler == nil ? 0.0 : [self sdl_totalBytesToUpload:files]);
    __block float totalBytesUploaded = 0.0;

    dispatch_group_t uploadFilesTask = dispatch_group_create();
    dispatch_group_enter(uploadFilesTask);

    // Wait for all files to be uploaded
    dispatch_group_notify(uploadFilesTask, [SDLGlobals sharedGlobals].sdlProcessingQueue, ^{
        if (completionHandler == nil) { return; }
        if (failedUploads.count > 0) {
            return completionHandler([NSError sdl_fileManager_unableToUpload_ErrorWithUserInfo:failedUploads]);
        }
        return completionHandler(nil);
    });

    for(NSUInteger i = 0; i < files.count; i++) {
        SDLFile *file = files[i];
        dispatch_group_enter(uploadFilesTask);
        __weak typeof(self) weakself = self;
        [self uploadFile:file completionHandler:^(BOOL success, NSUInteger bytesAvailable, NSError * _Nullable error) {
            if (!success) {
                failedUploads[file.name] = error;
            }

            // Send an update for each file sent to the remote
            if (progressHandler != nil) {
                totalBytesUploaded += file.fileSize;
                float uploadPercentage = [weakself sdl_uploadPercentage:totalBytesToUpload uploadedBytes:totalBytesUploaded];
                BOOL continueWithRemainingUploads = progressHandler(file.name, uploadPercentage, error);
                if (!continueWithRemainingUploads) {
                    // Cancel any remaining files waiting to be uploaded
                    for(NSUInteger j = i + 1; j < files.count; j++) {
                        SDLFile *cancelFile = files[j];
                        for (SDLUploadFileOperation *op in weakself.transactionQueue.operations) {
                            if ([op.fileWrapper.file isEqual:cancelFile]) {
                                [op cancel];
                                break;
                            }
                        }
                    }

                    dispatch_group_leave(uploadFilesTask);
                    BLOCK_RETURN;
                }
            }
            dispatch_group_leave(uploadFilesTask);
        }];
    }
    dispatch_group_leave(uploadFilesTask);
}

- (void)uploadFile:(SDLFile *)file completionHandler:(nullable SDLFileManagerUploadCompletionHandler)handler {
    if (file == nil || file.data.length == 0) {
        if (handler != nil) {
            handler(NO, self.bytesAvailable, [NSError sdl_fileManager_dataMissingError]);
        }
        return;
    }

    if (file.isStaticIcon) {
        if (handler != nil) {
            handler(NO, self.bytesAvailable, [NSError sdl_fileManager_staticIconError]);
        }
        return;
    }

    // Make sure we are able to send files
    if (![self.currentState isEqualToString:SDLFileManagerStateReady]) {
        if (handler != nil) {
            handler(NO, self.bytesAvailable, [NSError sdl_fileManager_unableToUploadError]);
        }
        return;
    }

    // If we didn't error out over the overwrite, then continue on
    [self sdl_uploadFile:file completionHandler:handler];
}

- (void)sdl_uploadFile:(SDLFile *)file completionHandler:(nullable SDLFileManagerUploadCompletionHandler)handler {
    SDLFile *fileCopy = [file copy];

    __weak typeof(self) weakSelf = self;
    SDLFileWrapper *fileWrapper = [SDLFileWrapper wrapperWithFile:fileCopy completionHandler:^(BOOL success, NSUInteger bytesAvailable, NSError *_Nullable error) {
        if (success) {
            weakSelf.bytesAvailable = bytesAvailable;
            [weakSelf.mutableRemoteFileNames addObject:fileCopy.name];

            if (!file.persistent) {
                [weakSelf.uploadedEphemeralFileNames addObject:fileCopy.name];
            }
        } else if (error.code != SDLFileManagerErrorCannotOverwrite) {
            weakSelf.failedFileUploadsCount = [weakSelf.class sdl_incrementFailedUploadCountForFileName:fileCopy.name failedFileUploadsCount:weakSelf.failedFileUploadsCount];

            NSUInteger maxUploadCount = [fileCopy isMemberOfClass:[SDLArtwork class]] ? weakSelf.maxArtworkUploadAttempts : weakSelf.maxFileUploadAttempts;
            if ([weakSelf sdl_canFileBeUploadedAgain:fileCopy maxUploadCount:maxUploadCount failedFileUploadsCount:weakSelf.failedFileUploadsCount]) {
                SDLLogD(@"Attempting to resend file with name %@ after a failed upload attempt", file.name);
                return [weakSelf sdl_uploadFile:fileCopy completionHandler:handler];
            }
        }

        if (handler != nil) {
            handler(success, bytesAvailable, error);
        }
    }];

    SDLUploadFileOperation *uploadOperation = [[SDLUploadFileOperation alloc] initWithFile:fileWrapper connectionManager:self.connectionManager fileManager:self];
    [self.transactionQueue addOperation:uploadOperation];
}

#pragma mark Artworks

- (BOOL)fileNeedsUpload:(nullable SDLFile *)file {
    if (file == nil || file.isStaticIcon) { return NO; }

    return (file.overwrite || ![self hasUploadedFile:file]);
}

- (void)uploadArtwork:(SDLArtwork *)artwork completionHandler:(nullable SDLFileManagerUploadArtworkCompletionHandler)completion {
    __weak typeof(self) weakself = self;
    [self uploadFile:artwork completionHandler:^(BOOL success, NSUInteger bytesAvailable, NSError * _Nullable error) {
        if (completion == nil) { return; }
        if ([weakself sdl_isErrorCannotOverwriteError:error]) {
            // Artwork with same name already uploaded to remote
            return completion(YES, artwork.name, bytesAvailable, nil);
        }
        completion(success, artwork.name, bytesAvailable, error);
    }];
}

- (void)uploadArtworks:(NSArray<SDLArtwork *> *)artworks completionHandler:(nullable SDLFileManagerMultiUploadArtworkCompletionHandler)completion {
    [self uploadArtworks:artworks progressHandler:nil completionHandler:completion];
}

- (void)uploadArtworks:(NSArray<SDLArtwork *> *)artworks progressHandler:(nullable SDLFileManagerMultiUploadArtworkProgressHandler)progressHandler completionHandler:(nullable SDLFileManagerMultiUploadArtworkCompletionHandler)completion {
    if (artworks.count == 0) {
        @throw [NSException sdl_missingFilesException];
    }

    __weak typeof(self) weakself = self;
    [self uploadFiles:artworks progressHandler:^BOOL(SDLFileName * _Nonnull fileName, float uploadPercentage, NSError * _Nullable error) {
        if (progressHandler == nil) { return YES; }
        if ([weakself sdl_isErrorCannotOverwriteError:error]) {
            return progressHandler(fileName, uploadPercentage, nil);
        }
        return progressHandler(fileName, uploadPercentage, error);
    } completionHandler:^(NSError * _Nullable error) {
        if (completion == nil) { return; }

        NSMutableSet<NSString *> *successfulArtworkUploadNames = [NSMutableSet set];
        for (SDLArtwork *artwork in artworks) {
            [successfulArtworkUploadNames addObject:artwork.name];
        }
        NSMutableDictionary *unsuccessfulArtworkUploadErrorUserInfo = [[NSMutableDictionary alloc] initWithDictionary:error.userInfo];

        if (error != nil) {
            for (NSString *erroredArtworkName in error.userInfo) {
                if (![weakself sdl_isErrorCannotOverwriteError:error.userInfo[erroredArtworkName]]) {
                    [successfulArtworkUploadNames removeObject:erroredArtworkName];
                } else {
                    // An overwrite error means that an artwork with the same name is already uploaded to the remote
                    [unsuccessfulArtworkUploadErrorUserInfo removeObjectForKey:erroredArtworkName];
                }
            }
        }

        return completion([NSArray arrayWithArray:[successfulArtworkUploadNames allObjects]], unsuccessfulArtworkUploadErrorUserInfo.count == 0 ? nil : [[NSError alloc] initWithDomain:error.domain code:error.code userInfo:unsuccessfulArtworkUploadErrorUserInfo]);
    }];
}

#pragma mark Helpers

/**
 *  Checks an error returned by Core to see if it is a "can not overwrite" error.
 *
 *  @param error    The error returned by SDL Core
 *  @return         True if the error is an overwrite error; false if not
 */
- (BOOL)sdl_isErrorCannotOverwriteError:(NSError * _Nullable)error {
    if (error != nil && error.domain == SDLErrorDomainFileManager && error.code == SDLFileManagerErrorCannotOverwrite) {
        return YES;
    }
    return NO;
}

/**
 *  Computes the total amount of bytes to be uploaded to the remote. This total is computed by summing up the file size of all files to be uploaded to the remote
 *
 *  @param files All the files being uploaded to the remote
 *  @return The total byte count
 */
- (float)sdl_totalBytesToUpload:(NSArray<SDLFile *> *)files {
    float totalBytes = 0.0;
    for(SDLFile *file in files) {
        totalBytes += file.fileSize;
    }

    return totalBytes;
}

/**
 * Computes the percentage of files uploaded to the remote. This percentage is a decimal number between 0.0 - 1.0. It is calculated by dividing the total number of bytes in files successfully or unsuccessfully uploaded by the total number of bytes in all files to be uploaded.
 *
 *  @param totalBytes      The total number of bytes in all files to be uploaded
 *  @param uploadedBytes   The total number of bytes in files successfully or unsuccessfully uploaded
 *  @return                The upload percentage
 */
- (float)sdl_uploadPercentage:(float)totalBytes uploadedBytes:(float)uploadedBytes {
    if (totalBytes == 0 || uploadedBytes == 0) {
        return 0.0;
    }
    return uploadedBytes / totalBytes;
}

#pragma mark Reuploads

/**
 *  Checks if an artwork needs to be uploaded to Core. The arwork should not be sent to Core if the artwork is already on Core or if the artwork is not on Core after the maximum number of repeated upload attempts has been reached.
 *
 *  @param file             The file to be uploaded to Core
 *  @param maxUploadCount   The max number of times the file is allowed to be uploaded to Core
 *  @return                 True if the file still needs to be (re)sent to Core; false if not.
 */
- (BOOL)sdl_canFileBeUploadedAgain:(nullable SDLFile *)file maxUploadCount:(NSUInteger)maxUploadCount failedFileUploadsCount:(NSMutableDictionary<SDLFileName *, NSNumber<SDLUInt> *> *)failedFileUploadsCount {
    if (![self.currentState isEqualToString:SDLFileManagerStateReady]) {
        SDLLogW(@"File named %@ failed to upload. The file manager has shutdown so the file upload will not retry.", file.name);
        return NO;
    }

    if (!file) {
        SDLLogE(@"File can not be uploaded because it is not a valid file.");
        return NO;
    }

    if ([self hasUploadedFile:file]) {
        SDLLogD(@"File named %@ has already been uploaded.", file.name);
        return NO;
    }

    NSNumber *failedUploadCount = failedFileUploadsCount[file.name];
    BOOL canFileBeUploadedAgain = (failedUploadCount == nil) ? YES : (failedUploadCount.unsignedIntegerValue < maxUploadCount);
    if (!canFileBeUploadedAgain) {
        SDLLogE(@"File named %@ failed to upload. Max number of upload attempts reached.", file.name);
    }

    return canFileBeUploadedAgain;
}

/**
 *  Increments the number of upload attempts for a file name by 1.
 *
 *  @param fileName The name used to upload the file to Core
 */
+ (NSMutableDictionary<SDLFileName *, NSNumber<SDLUInt> *> *)sdl_incrementFailedUploadCountForFileName:(SDLFileName *)fileName failedFileUploadsCount:(NSMutableDictionary<SDLFileName *, NSNumber<SDLUInt> *> *)failedFileUploadsCount {
    NSNumber *currentFailedUploadCount = failedFileUploadsCount[fileName];
    NSNumber *newFailedUploadCount = (currentFailedUploadCount != nil) ? @(currentFailedUploadCount.integerValue + 1) : @1;
    failedFileUploadsCount[fileName] = newFailedUploadCount;
    SDLLogW(@"File with name %@ failed to upload %@ times", fileName, newFailedUploadCount);
    return failedFileUploadsCount;
}

#pragma mark - Temporary Files

+ (NSURL *)temporaryFileDirectory {
    NSURL *directoryURL = [self.class sdl_temporaryFileDirectoryName];
    if (![[NSFileManager defaultManager] fileExistsAtPath:[directoryURL path]]) {
        [[NSFileManager defaultManager] createDirectoryAtURL:directoryURL withIntermediateDirectories:NO attributes:nil error:nil];
    }

    return directoryURL;
}

+ (NSURL *)sdl_temporaryFileDirectoryName {
    return [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent:@"SDL"]];
}

+ (void)sdl_clearTemporaryFileDirectory {
    NSError *error = nil;
    if (![[NSFileManager defaultManager] fileExistsAtPath:[self.class sdl_temporaryFileDirectoryName].absoluteString]) {
        [[NSFileManager defaultManager] removeItemAtURL:[self.class sdl_temporaryFileDirectoryName] error:&error];
    }

    if (error != nil) {
        SDLLogW(@"[Error clearing temporary file directory] %@", error);
    }
}


@end


NS_ASSUME_NONNULL_END