test(dash): [PKG-DASH-05] isolate SDK paused-seek buffer metric deadlock

test/browser/dash-buffer-observer.js

@@ -0,0 +1,50 @@
+// Runs inside the page. Every SDK operation still uses the native SourceBuffer.
+export function observeDashBuffers() {
+  const buffers = []
+  const events = []
+  const ranges = value => Array.from({ length: value.length }, (_, index) => [value.start(index), value.end(index)])
+  function snapshot() {
+    const video = window.art?.video || window.nativeVideo
+    const dash = window.art?.dash || window.nativeDash
+    const metrics = dash?.getDashMetrics()
+    let processors
+    try {
+      processors = dash?.getActiveStream()?.getProcessors().map((processor) => {
+        const buffer = processor.getBufferController()
+        return { type: processor.getType(), level: processor.getBufferLevel(), target: processor.getScheduleController().getBufferTarget(), complete: processor.isBufferingCompleted(), pruning: buffer.getIsPruningInProgress(), hasTarget: video ? buffer.hasBufferAtTime(video.currentTime) : null }
+      })
+    }
+    catch (error) {
+      // SDK initialization/teardown and generations expose different internals.
+      processors = { unavailable: String(error) }
+    }
+    return {
+      time: video?.currentTime,
+      paused: video?.paused,
+      seeking: video?.seeking,
+      readyState: video?.readyState,
+      video: video ? ranges(video.buffered) : [],
+      levels: metrics ? { video: metrics.getCurrentBufferLevel('video'), audio: metrics.getCurrentBufferLevel('audio') } : null,
+      processors,
+      buffers: buffers.map(({ source, buffer, mime }) => {
+        try {
+          return { mime, sourceState: source.readyState, updating: buffer.updating, ranges: ranges(buffer.buffered), timestampOffset: buffer.timestampOffset }
+        }
+        catch (error) {
+          return { mime, sourceState: source.readyState, error: error.name }
+        }
+      }),
+    }
+  }
+  const mark = name => events.push({ name, at: performance.now(), ...snapshot() })
+  for (const Source of new Set([window.MediaSource, window.ManagedMediaSource].filter(Boolean))) {
+    const addSourceBuffer = Source.prototype.addSourceBuffer
+    Source.prototype.addSourceBuffer = function (...args) {
+      const buffer = Reflect.apply(addSourceBuffer, this, args)
+      buffers.push({ source: this, buffer, mime: args[0] })
+      buffer.addEventListener('updateend', () => mark('sourcebuffer:updateend'))
+      return buffer
+    }
+  }
+  window.dashBuffers = { snapshot, mark, events }
+}