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

packages/artplayer/src/subtitle/state.ts

@@ -0,0 +1,45 @@
+import type ResourceScope from '../lifecycle/scope'
+import { getScope } from '../lifecycle/instance'
+import SubtitleRequest from './request'
+
+export interface SubtitleState {
+  scope: ResourceScope
+  request?: SubtitleRequest
+  track?: ResourceScope
+  ownedURL?: string
+  revision: number
+  render: number
+  trackRevision: number
+}
+
+const states = new WeakMap<object, SubtitleState>()
+
+export function initSubtitleState(subtitle: object, art: object): SubtitleState {
+  const scope = getScope(art).child()
+  const state: SubtitleState = { scope, revision: 0, render: 0, trackRevision: 0 }
+  states.set(subtitle, state)
+  scope.add(() => {
+    releaseSubtitleURL(state)
+  })
+  return state
+}
+
+export function subtitleState(subtitle: object): SubtitleState {
+  return states.get(subtitle)!
+}
+
+export function beginSubtitleRequest(state: SubtitleState): SubtitleRequest {
+  const previous = state.request
+  const request = new SubtitleRequest(state.scope)
+  state.request = request
+  state.revision += 1
+  previous?.cancel()
+  return request
+}
+
+export function releaseSubtitleURL(state: SubtitleState): void {
+  const url = state.ownedURL
+  state.ownedURL = undefined
+  if (url)
+    URL.revokeObjectURL(url)
+}