Advance Blender 5.2 web parity through M12-03D

web/app/src/sequencer/SequencerMediaProxyCache.ts

@@ -42,7 +42,13 @@ async function sha256(data: ArrayBuffer): Promise<string> {
   return Array.from(new Uint8Array(result), (value) => value.toString(16).padStart(2, "0")).join("");
 }
 
-function waitForLoadedFrame(video: HTMLVideoElement, timeoutMs: number): Promise<void> {
+function cancelled(signal: AbortSignal | undefined): void {
+  if (signal?.aborted) {
+    throw new SequencerMediaCacheValidationError("SEQUENCER_CANCELLED", "Movie proxy generation was cancelled");
+  }
+}
+
+function waitForLoadedFrame(video: HTMLVideoElement, timeoutMs: number, signal?: AbortSignal): Promise<void> {
   if (video.readyState >= HTMLMediaElement.HAVE_CURRENT_DATA) return Promise.resolve();
   return new Promise((resolve, reject) => {
     const timeout = window.setTimeout(() => finish(new Error("timeout")), timeoutMs);
@@ -50,12 +56,16 @@ function waitForLoadedFrame(video: HTMLVideoElement, timeoutMs: number): Promise
       window.clearTimeout(timeout);
       video.removeEventListener("loadeddata", ready);
       video.removeEventListener("error", failed);
+      signal?.removeEventListener("abort", aborted);
       if (error) reject(error); else resolve();
     };
     const ready = (): void => finish();
     const failed = (): void => finish(new Error("decode"));
+    const aborted = (): void => finish(new SequencerMediaCacheValidationError("SEQUENCER_CANCELLED", "Movie proxy generation was cancelled"));
     video.addEventListener("loadeddata", ready, { once: true });
     video.addEventListener("error", failed, { once: true });
+    signal?.addEventListener("abort", aborted, { once: true });
+    if (signal?.aborted) aborted();
   });
 }
 
@@ -64,7 +74,9 @@ export async function generateInitialSequencerMovieProxyFrame(
   capabilityValue: unknown,
   profileValue: unknown,
   sourceData: ArrayBuffer,
+  signal?: AbortSignal,
 ): Promise<SequencerGeneratedProxyFrameIR> {
+  cancelled(signal);
   const source = parseSequencerCodecProbeRequest(sourceValue);
   const capability = parseSequencerCodecProbeResult(capabilityValue);
   const profile = parseSequencerMediaProxyProfile(profileValue);
@@ -75,6 +87,7 @@ export async function generateInitialSequencerMovieProxyFrame(
   if (!(sourceData instanceof ArrayBuffer) || sourceData.byteLength !== source.byteLength || await sha256(sourceData) !== source.sourceSha256) {
     throw new SequencerMediaCacheValidationError("SEQUENCER_CACHE_SOURCE_MISMATCH", "Movie proxy source bytes failed identity verification");
   }
+  cancelled(signal);
   if (typeof document === "undefined" || typeof HTMLMediaElement === "undefined") {
     throw new SequencerMediaCacheValidationError("SEQUENCER_CODEC_UNSUPPORTED", "HTML media proxy generation is unavailable");
   }
@@ -87,7 +100,8 @@ export async function generateInitialSequencerMovieProxyFrame(
   try {
     video.src = url;
     video.load();
-    await waitForLoadedFrame(video, 10_000);
+    await waitForLoadedFrame(video, 10_000, signal);
+    cancelled(signal);
     const canvas = document.createElement("canvas");
     canvas.width = profile.width;
     canvas.height = profile.height;
@@ -97,6 +111,7 @@ export async function generateInitialSequencerMovieProxyFrame(
     }
     context.clearRect(0, 0, profile.width, profile.height);
     context.drawImage(video, 0, 0, profile.width, profile.height);
+    cancelled(signal);
     const pixels = context.getImageData(0, 0, profile.width, profile.height).data;
     const data = pixels.buffer.slice(pixels.byteOffset, pixels.byteOffset + pixels.byteLength);
     return {