refactor(mediabunny): [PKG-MB-06] own audio clocks, buffers and context lifecycle

packages/artplayer-proxy-mediabunny/src/audio-context.ts

@@ -0,0 +1,92 @@
+interface ContextHost {
+  audioContext: AudioContext | null
+  gainNode: GainNode | null
+  volume: number
+  muted: boolean
+}
+
+export default class ContextOwner {
+  private closed = false
+  private resumes = new WeakMap<AudioContext, Promise<void>>()
+
+  constructor(private host: ContextHost) {}
+
+  ensure(sampleRate?: number): AudioContext | null {
+    if (this.closed)
+      return null
+    if (this.host.audioContext)
+      return this.host.audioContext
+    const Context = window.AudioContext || (window as Window & { webkitAudioContext?: typeof AudioContext }).webkitAudioContext
+    let context: AudioContext
+    try {
+      context = new Context({ sampleRate })
+    }
+    catch {
+      context = new Context()
+    }
+    if (this.closed) {
+      void context.close().catch(error => console.warn('MediaBunny obsolete context cleanup:', error))
+      return null
+    }
+    let gain: GainNode | null = null
+    try {
+      gain = context.createGain()
+      gain.connect(context.destination)
+      const volume = this.host.muted ? 0 : this.host.volume
+      gain.gain.value = volume * volume
+      if (this.closed) {
+        gain.disconnect()
+        void context.close().catch(error => console.warn('MediaBunny obsolete context cleanup:', error))
+        return null
+      }
+      this.host.audioContext = context
+      this.host.gainNode = gain
+      return context
+    }
+    catch (error) {
+      try {
+        gain?.disconnect()
+      }
+      catch (failure) { console.warn('MediaBunny gain setup cleanup:', failure) }
+      void context.close().catch(failure => console.warn('MediaBunny context setup cleanup:', failure))
+      throw error
+    }
+  }
+
+  updateGain(): void {
+    if (!this.host.gainNode)
+      return
+    const volume = this.host.muted ? 0 : this.host.volume
+    this.host.gainNode.gain.value = volume * volume
+  }
+
+  resume(context: AudioContext): Promise<void> {
+    const previous = this.resumes.get(context)
+    if (previous)
+      return previous
+    const pending = context.resume()
+    this.resumes.set(context, pending)
+    const clear = () => {
+      if (this.resumes.get(context) === pending)
+        this.resumes.delete(context)
+    }
+    pending.then(clear, clear)
+    return pending
+  }
+
+  destroy(): void {
+    if (this.closed)
+      return
+    this.closed = true
+    const { audioContext: context, gainNode: gain } = this.host
+    this.host.audioContext = null
+    this.host.gainNode = null
+    try {
+      gain?.disconnect()
+    }
+    finally {
+      if (context)
+        void context.close().catch(error => console.warn('MediaBunny context close error:', error))
+    }
+  }
+}