refactor(mediabunny): [PKG-MB-04] checkpoint typed shim and event cleanup

packages/artplayer-proxy-mediabunny/src/shim-frames.ts

@@ -0,0 +1,61 @@
+import type { EnginePort } from './engine-types'
+
+interface FrameOwner {
+  engine: Pick<EnginePort, 'currentTime' | 'videoWidth' | 'videoHeight'>
+}
+
+interface FrameState {
+  closed: boolean
+  frames: Set<number>
+}
+
+// Keep resource bookkeeping off the observable shim own-property/canvas surface.
+const states = new WeakMap<FrameOwner, FrameState>()
+function state(owner: FrameOwner): FrameState {
+  let value = states.get(owner)
+  if (!value) {
+    value = { closed: false, frames: new Set() }
+    states.set(owner, value)
+  }
+  return value
+}
+
+export function requestFrame(owner: FrameOwner, callback: VideoFrameRequestCallback): number {
+  const resource = state(owner)
+  if (resource.closed)
+    return 0
+  const id = requestAnimationFrame((time) => {
+    resource.frames.delete(id)
+    if (resource.closed)
+      return
+    callback(time, {
+      presentationTime: owner.engine.currentTime,
+      expectedDisplayTime: time + 16.6,
+      width: owner.engine.videoWidth,
+      height: owner.engine.videoHeight,
+      mediaTime: owner.engine.currentTime,
+      presentedFrames: 0,
+      processingDuration: 0,
+      captureTime: time,
+      receiveTime: time,
+      rtpTimestamp: 0,
+    })
+  })
+  resource.frames.add(id)
+  return id
+}
+
+export function cancelFrame(owner: FrameOwner, id: number): void {
+  state(owner).frames.delete(id)
+  cancelAnimationFrame(id)
+}
+
+export function closeFrames(owner: FrameOwner): boolean {
+  const resource = state(owner)
+  if (resource.closed)
+    return false
+  resource.closed = true
+  for (const id of resource.frames) cancelAnimationFrame(id)
+  resource.frames.clear()
+  return true
+}