feat(S3): implements suspend and resume features for multipart upload tasks

AWSS3/AWSS3TransferUtility+HeaderHelper.m

@@ -52,7 +52,7 @@ - (void)assignRequestParameters:(AWSS3GetPreSignedURLRequest *)getPreSignedURLRe
 
 @implementation AWSS3TransferUtility (HeaderHelper)
 
--(void) filterAndAssignHeaders:(NSDictionary<NSString *, NSString *> *) requestHeaders
+- (void)filterAndAssignHeaders:(NSDictionary<NSString *, NSString *> *) requestHeaders
         getPresignedURLRequest:(AWSS3GetPreSignedURLRequest *) getPresignedURLRequest
                     URLRequest: (NSMutableURLRequest *) URLRequest {
 

AWSS3/AWSS3TransferUtility.h

@@ -620,6 +620,30 @@ handleEventsForBackgroundURLSession:(NSString *)identifier
                                                     expression:(nullable AWSS3TransferUtilityDownloadExpression *)expression
                                              completionHandler:(nullable AWSS3TransferUtilityDownloadCompletionHandlerBlock)completionHandler;
 
+///**
+// Suspends multipart upload
+// @param multipartUploadTask task
+// */
+//- (nullable NSError *)suspendMultipartUpload:(AWSS3TransferUtilityMultiPartUploadTask *)multipartUploadTask;
+
+/**
+ Suspends all multipart uploads.
+ @param completionHandler completion handler
+ */
+- (void)suspendAllMultipartUploadsWithCompletionHandler:(nullable AWSS3TransferUtilityMultiPartUploadSuspendBlock)completionHandler;
+
+///**
+//  Resumes a multipart upload.
+// @param multiPartUploadTask   The task to resume
+// */
+//- (nullable NSError *)resumeMultipartUpload:(nonnull AWSS3TransferUtilityMultiPartUploadTask *)multiPartUploadTask;
+
+/**
+  Resumes all multipart uploads.
+ @param completionHandler completion handler  
+ */
+- (void)resumeAllMultipartUploadsWithCompletionHandler:(nullable AWSS3TransferUtilityMultiPartUploadResumeBlock)completionHandler;
+
 /**
  Assigns progress feedback and completion handler blocks. This method should be called when the app was suspended while the transfer is still happening.
 

AWSS3/AWSS3TransferUtilityDatabaseHelper.m

@@ -127,6 +127,9 @@ + (void) updateTransferRequestInDB: (NSString *) transferID
                             status: (AWSS3TransferUtilityTransferStatusType) status
                        retry_count: (NSUInteger) retryCount
                      databaseQueue: (AWSFMDatabaseQueue *) databaseQueue {
+    if (eTag == nil) {
+        eTag = @"";
+    }
     NSString *const AWSS3TransferUtilityUpdateTransferUtilityStatusAndETag = @"UPDATE awstransfer "
     @"SET status=:status, etag = :etag, session_task_id = :session_task_id, retry_count = :retry_count "
     @"WHERE transfer_id=:transfer_id and "

AWSS3/AWSS3TransferUtilityTasks.h

@@ -87,6 +87,20 @@ typedef void (^AWSS3TransferUtilityMultiPartProgressBlock) (AWSS3TransferUtility
                                                             NSProgress *progress);
 
 
+/**
+ The suspend multipart upload completion handler.
+
+ @param error    Returns the error object when the suspending failed. Returns `nil` on success.
+ */
+typedef void (^AWSS3TransferUtilityMultiPartUploadSuspendBlock) (NSError * _Nullable error);
+
+/**
+ The resume multipart upload completion handler.
+
+ @param error    Returns the error object when the resume failed. Returns `nil` on success.
+ */
+typedef void (^AWSS3TransferUtilityMultiPartUploadResumeBlock) (NSError * _Nullable error);
+
 #pragma mark - AWSS3TransferUtilityTasks
 
 /**
@@ -140,6 +154,11 @@ typedef void (^AWSS3TransferUtilityMultiPartProgressBlock) (AWSS3TransferUtility
  */
 @property (nullable, readonly) NSHTTPURLResponse *response;
 
+/**
+ Error after operation.
+ */
+@property (nullable, readonly) NSError *error;
+
 /**
  Cancels the task.
  */