fix: Do not close JS stream reader if closed

unoplatform · Apr 19, 2021 · 4fa0db3 · 4fa0db3
1 parent 3207821
commit 4fa0db3
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Showing 2 changed files with 34 additions and 2 deletions.
diff --git a/src/Uno.UI/WasmScripts/Uno.UI.js b/src/Uno.UI/WasmScripts/Uno.UI.js
@@ -3540,6 +3540,7 @@ var Uno;
                 }
                 static async readAsync(streamId, targetArrayPointer, offset, count, position) {
                     var streamReader;
+                    var readerNeedsRelease = true;
                     try {
                         const instance = NativeFileReadStream._streamMap.get(streamId);
                         var totalRead = 0;
@@ -3553,10 +3554,23 @@ var Uno;
                             totalRead += chunk.value.length;
                             chunk = await streamReader.read();
                         }
+                        // If this is the end of stream, it closed itself
+                        readerNeedsRelease = !chunk.done;
                         return totalRead.toString();
                     }
                     finally {
-                        if (streamReader) {
+                        // Reader must be released only if the underlying stream has not already closed it.				
+                        // Otherwise the release operation sets a new Promise.reject as reader.closed which
+                        // raises silent but observable exception in Chromium-based browsers.
+                        if (streamReader && readerNeedsRelease) {
+                            // Silently handling TypeError exceptions on closed event as the releaseLock()
+                            // raises one in case of a successful close.
+                            streamReader.closed.catch(reason => {
+                                if (!(reason instanceof TypeError)) {
+                                    throw reason;
+                                }
+                            });
+                            streamReader.cancel();
                             streamReader.releaseLock();
                         }
                     }

diff --git a/src/Uno.UI/ts/Windows/Storage/Streams/NativeFileReadStream.ts b/src/Uno.UI/ts/Windows/Storage/Streams/NativeFileReadStream.ts
@@ -20,12 +20,14 @@
 
 		public static async readAsync(streamId: string, targetArrayPointer: number, offset: number, count: number, position: number): Promise<string> {
 			var streamReader: ReadableStreamDefaultReader;
+			var readerNeedsRelease = true;
 			try {
 				const instance = NativeFileReadStream._streamMap.get(streamId);
 
 				var totalRead = 0;
 				var stream = await instance._file.slice(position, position + count).stream();
 				streamReader = stream.getReader();
+
 				var chunk = await streamReader.read();
 				while (!chunk.done && chunk.value) {
 					for (var i = 0; i < chunk.value.length; i++) {
@@ -36,10 +38,26 @@
 					chunk = await streamReader.read();
 				}
 
+				// If this is the end of stream, it closed itself
+				readerNeedsRelease = !chunk.done;
+
 				return totalRead.toString();
 			}
 			finally {
-				if (streamReader) {
+				// Reader must be released only if the underlying stream has not already closed it.				
+				// Otherwise the release operation sets a new Promise.reject as reader.closed which
+				// raises silent but observable exception in Chromium-based browsers.
+				if (streamReader && readerNeedsRelease) {
+
+					// Silently handling TypeError exceptions on closed event as the releaseLock()
+					// raises one in case of a successful close.
+					streamReader.closed.catch(reason => {
+						if (!(reason instanceof TypeError)) {
+							throw reason;
+						}
+					});
+
+					streamReader.cancel();
 					streamReader.releaseLock();
 				}
 			}