Only fail a StorageTask once (#5245)

Author: paulb777

FirebaseStorage/CHANGELOG.md

@@ -1,3 +1,7 @@
+# Unreleased
+- [fixed] Fix a rare case where a StorageTask would call its completion callbacks more than
+  once. (#5245)
+
 # 3.6.0
 - [added] Added watchOS support for Firebase Storage. (#4955)
 

FirebaseStorage/Sources/FIRStorageReference.m

@@ -174,6 +174,7 @@ - (FIRStorageUploadTask *)putData:(NSData *)uploadData
                                              metadata:metadata];
 
   if (completion) {
+    __block BOOL completed = NO;
     dispatch_queue_t callbackQueue = _storage.fetcherServiceForApp.callbackQueue;
     if (!callbackQueue) {
       callbackQueue = dispatch_get_main_queue();
@@ -182,13 +183,19 @@ - (FIRStorageUploadTask *)putData:(NSData *)uploadData
     [task observeStatus:FIRStorageTaskStatusSuccess
                 handler:^(FIRStorageTaskSnapshot *_Nonnull snapshot) {
                   dispatch_async(callbackQueue, ^{
-                    completion(snapshot.metadata, nil);
+                    if (!completed) {
+                      completed = YES;
+                      completion(snapshot.metadata, nil);
+                    }
                   });
                 }];
     [task observeStatus:FIRStorageTaskStatusFailure
                 handler:^(FIRStorageTaskSnapshot *_Nonnull snapshot) {
                   dispatch_async(callbackQueue, ^{
-                    completion(nil, snapshot.error);
+                    if (!completed) {
+                      completed = YES;
+                      completion(nil, snapshot.error);
+                    }
                   });
                 }];
   }
@@ -222,6 +229,7 @@ - (FIRStorageUploadTask *)putFile:(NSURL *)fileURL
                                              metadata:metadata];
 
   if (completion) {
+    __block BOOL completed = NO;
     dispatch_queue_t callbackQueue = _storage.fetcherServiceForApp.callbackQueue;
     if (!callbackQueue) {
       callbackQueue = dispatch_get_main_queue();
@@ -230,13 +238,19 @@ - (FIRStorageUploadTask *)putFile:(NSURL *)fileURL
     [task observeStatus:FIRStorageTaskStatusSuccess
                 handler:^(FIRStorageTaskSnapshot *_Nonnull snapshot) {
                   dispatch_async(callbackQueue, ^{
-                    completion(snapshot.metadata, nil);
+                    if (!completed) {
+                      completed = YES;
+                      completion(snapshot.metadata, nil);
+                    }
                   });
                 }];
     [task observeStatus:FIRStorageTaskStatusFailure
                 handler:^(FIRStorageTaskSnapshot *_Nonnull snapshot) {
                   dispatch_async(callbackQueue, ^{
-                    completion(nil, snapshot.error);
+                    if (!completed) {
+                      completed = YES;
+                      completion(nil, snapshot.error);
+                    }
                   });
                 }];
   }
@@ -248,6 +262,7 @@ - (FIRStorageUploadTask *)putFile:(NSURL *)fileURL
 
 - (FIRStorageDownloadTask *)dataWithMaxSize:(int64_t)size
                                  completion:(FIRStorageVoidDataError)completion {
+  __block BOOL completed = NO;
   FIRStorageDownloadTask *task =
       [[FIRStorageDownloadTask alloc] initWithReference:self
                                          fetcherService:_storage.fetcherServiceForApp
@@ -263,13 +278,20 @@ - (FIRStorageDownloadTask *)dataWithMaxSize:(int64_t)size
               handler:^(FIRStorageTaskSnapshot *_Nonnull snapshot) {
                 FIRStorageDownloadTask *task = snapshot.task;
                 dispatch_async(callbackQueue, ^{
-                  completion(task.downloadData, nil);
+                  if (!completed) {
+                    completed = YES;
+                    completion(task.downloadData, nil);
+                  }
                 });
               }];
+
   [task observeStatus:FIRStorageTaskStatusFailure
               handler:^(FIRStorageTaskSnapshot *_Nonnull snapshot) {
                 dispatch_async(callbackQueue, ^{
-                  completion(nil, snapshot.error);
+                  if (!completed) {
+                    completed = YES;
+                    completion(nil, snapshot.error);
+                  }
                 });
               }];
   [task
@@ -302,6 +324,7 @@ - (FIRStorageDownloadTask *)writeToFile:(NSURL *)fileURL
                                           dispatchQueue:_storage.dispatchQueue
                                                    file:fileURL];
   if (completion) {
+    __block BOOL completed = NO;
     dispatch_queue_t callbackQueue = _storage.fetcherServiceForApp.callbackQueue;
     if (!callbackQueue) {
       callbackQueue = dispatch_get_main_queue();
@@ -310,13 +333,19 @@ - (FIRStorageDownloadTask *)writeToFile:(NSURL *)fileURL
     [task observeStatus:FIRStorageTaskStatusSuccess
                 handler:^(FIRStorageTaskSnapshot *_Nonnull snapshot) {
                   dispatch_async(callbackQueue, ^{
-                    completion(fileURL, nil);
+                    if (!completed) {
+                      completed = YES;
+                      completion(fileURL, nil);
+                    }
                   });
                 }];
     [task observeStatus:FIRStorageTaskStatusFailure
                 handler:^(FIRStorageTaskSnapshot *_Nonnull snapshot) {
                   dispatch_async(callbackQueue, ^{
-                    completion(nil, snapshot.error);
+                    if (!completed) {
+                      completed = YES;
+                      completion(nil, snapshot.error);
+                    }
                   });
                 }];
   }