refactor(thumbnail): [PKG-TOOL-THUMB-04] type runtime modules and retain emitter attribution

packages/artplayer-tool-thumbnail/src/lifecycle.ts

@@ -0,0 +1,83 @@
+import type ArtplayerToolThumbnail from './index'
+import type { Cleanup, LifecycleState } from './types'
+
+const states = new WeakMap<ArtplayerToolThumbnail, LifecycleState>()
+
+export function stateFor(tool: ArtplayerToolThumbnail): LifecycleState {
+  if (!states.has(tool)) {
+    states.set(tool, {
+      closed: false,
+      epoch: 0,
+      inputEpoch: 0,
+      job: null,
+      video: null,
+      sourceUrl: null,
+      thumbnailUrl: null,
+      sourceUrls: new Set(),
+      thumbnailUrls: new Set(),
+      sourceListeners: [],
+      loading: false,
+    })
+  }
+  return states.get(tool)!
+}
+
+export function cancellation(reason: string) {
+  const error = new Error(`Thumbnail task cancelled: ${reason}`)
+  error.name = 'AbortError'
+  return error
+}
+
+export function revoke(urls: Set<string>, url: string | undefined) {
+  if (!url)
+    return
+  urls.delete(url)
+  URL.revokeObjectURL(url)
+}
+
+export function cleanupAll(callbacks: Cleanup[]) {
+  let failure: unknown
+  for (const callback of callbacks) {
+    try {
+      callback()
+    }
+    catch (error) {
+      failure ||= error
+    }
+  }
+  if (failure)
+    throw failure
+}
+
+export function closeState(tool: ArtplayerToolThumbnail, reason = 'destroyed') {
+  const state = stateFor(tool)
+  if (state.closed)
+    return false
+  state.closed = true
+  state.epoch++
+  state.job?.cancel(reason)
+  return true
+}
+
+export function releaseMedia(tool: ArtplayerToolThumbnail) {
+  const state = stateFor(tool)
+  const sources = new Set([...state.sourceUrls, tool.videoUrl])
+  const thumbnails = new Set([...state.thumbnailUrls, tool.thumbnailUrl])
+  const media: Cleanup[] = []
+  for (const video of new Set([state.video, tool.video])) {
+    if (video) {
+      media.push(
+        () => video.pause?.(),
+        () => video.removeAttribute?.('src'),
+        () => video.load?.(),
+        () => video.parentNode?.removeChild(video),
+      )
+    }
+  }
+  cleanupAll([
+    ...state.sourceListeners.splice(0),
+    ...media,
+    ...[...sources].map(url => () => revoke(state.sourceUrls, url)),
+    ...[...thumbnails].map(url => () => revoke(state.thumbnailUrls, url)),
+  ])
+}