fix: cancel CDN download tasks on dealloc to prevent use-after-free

Source/Renderer/CDNFileAssetLoader.mm

@@ -12,26 +12,50 @@
 #import <RiveRuntime/RiveRuntime-Swift.h>
 
 @implementation CDNFileAssetLoader
-{}
+{
+    NSMutableArray<NSURLSessionTask*>* _activeTasks;
+}
+
+- (instancetype)init
+{
+    if (self = [super init])
+    {
+        _activeTasks = [NSMutableArray array];
+    }
+    return self;
+}
+
+- (void)dealloc
+{
+    for (NSURLSessionTask* task in _activeTasks)
+    {
+        [task cancel];
+    }
+}
 
 - (bool)loadContentsWithAsset:(RiveFileAsset*)asset
                       andData:(NSData*)data
                    andFactory:(RiveFactory*)factory
 {
     // TODO: Error handling
-    // TODO: Track tasks, so we can cancel them if we garbage collect the asset
-    // loader
 
     if ([[asset cdnUuid] length] > 0)
     {
         NSURL* URL =
             [NSURL URLWithString:[NSString stringWithFormat:@"%@/%@",
                                                             [asset cdnBaseUrl],
                                                             [asset cdnUuid]]];
-        NSURLSessionTask* task = [[NSURLSession sharedSession]
+        __block NSURLSessionTask* task = nil;
+        __weak CDNFileAssetLoader* weakSelf = self;
+        task = [[NSURLSession sharedSession]
             downloadTaskWithURL:URL
               completionHandler:^(
                   NSURL* location, NSURLResponse* response, NSError* error) {
+                CDNFileAssetLoader* strongSelf = weakSelf;
+                if (strongSelf)
+                {
+                    [strongSelf->_activeTasks removeObject:task];
+                }
                 if (!error)
                 {
                     // Load the data into the reader
@@ -65,9 +89,8 @@ - (bool)loadContentsWithAsset:(RiveFileAsset*)asset
                 }
               }];
 
-        // Kick off the http download
-        // QUESTION: Do we need to tie this into the RiveFile so we can wait for
-        // these loads to be completed?
+        // Track and start the download
+        [_activeTasks addObject:task];
         [task resume];
         return true;
     }