refactor(core): CORE-15 type subtitles and own request and track lifetimes

packages/artplayer/src/subtitle/track.ts

@@ -0,0 +1,83 @@
+import type { SubtitleView } from './types'
+import { releaseSubtitleURL, subtitleState } from './state'
+
+export function replaceSubtitleTrack(subtitle: SubtitleView, kind: string, url: string): void {
+  const state = subtitleState(subtitle)
+  if (state.scope.closed)
+    return
+  const revision = ++state.trackRevision
+  const { art } = subtitle
+  const { template } = art
+  const previous = template.$track
+  const parent = previous.parentNode
+  const next = previous.nextSibling
+  const track = document.createElement('track')
+  const scope = state.scope.child()
+  scope.add(() => {
+    track.onload = null
+    track.onerror = null
+  })
+  let committed = false
+  try {
+    track.default = true
+    track.kind = kind
+    track.src = url
+    track.label = art.option.subtitle.name || 'Artplayer'
+    track.track.mode = 'hidden'
+    track.onload = () => {
+      if (!scope.closed && template.$track === track)
+        art.emit('subtitleLoad', subtitle.cues, subtitle.option)
+    }
+    track.onerror = () => {
+      if (!scope.closed && template.$track === track)
+        art.notice.show = new Error('Failed to load subtitle track')
+    }
+    if (scope.closed || state.trackRevision !== revision) {
+      scope.dispose()
+      return
+    }
+    previous.remove()
+    template.$video.appendChild(track)
+    template.$track = track
+    const textTrack = subtitle.textTrack
+    const cleanup = textTrack
+      ? art.proxy(textTrack, 'cuechange', () => {
+          if (!scope.closed && template.$track === track)
+            subtitle.update()
+        })
+      : () => {}
+    scope.add(() => {
+      art.events.remove(cleanup)
+    })
+    if (scope.closed || state.trackRevision !== revision) {
+      scope.dispose()
+      track.remove()
+      return
+    }
+    const previousScope = state.track
+    state.track = scope
+    subtitle.destroyEvent = cleanup
+    previous.onload = null
+    previous.onerror = null
+    committed = true
+    try {
+      previousScope?.dispose()
+    }
+    finally {
+      if (state.ownedURL && state.ownedURL !== url)
+        releaseSubtitleURL(state)
+    }
+  }
+  catch (error) {
+    if (committed)
+      throw error
+    scope.dispose()
+    track.remove()
+    if (state.scope.closed || state.trackRevision !== revision)
+      throw error
+    template.$track = previous
+    if (parent)
+      parent.insertBefore(previous, next?.parentNode === parent ? next : null)
+    throw error
+  }
+}