fix(iframe): [PKG-IFRAME-03] own pending requests and cancellation

packages/artplayer-tool-iframe/src/requests.ts

@@ -0,0 +1,94 @@
+export interface Packet {
+  type: string
+  data?: any
+  id?: number
+}
+
+export interface Callbacks {
+  resove: (value?: any) => void
+  reject: (reason?: any) => void
+}
+
+export interface RequestHost {
+  $iframe: HTMLIFrameElement
+  promises: Record<number, Callbacks>
+  injected: boolean
+  destroyed: boolean
+}
+
+interface Pending {
+  id?: number
+  timer?: ReturnType<typeof setTimeout>
+  callbacks: Callbacks
+}
+
+const requests = new WeakMap<RequestHost, Set<Pending>>()
+let lastId = 0
+
+export function postRequest(host: RequestHost, { type, data }: Packet): Promise<any> {
+  return new Promise((resolve, reject) => {
+    if (host.destroyed) {
+      reject(new Error('The instance has been destroyed'))
+      return
+    }
+    const pending = requests.get(host) || new Set<Pending>()
+    requests.set(host, pending)
+    const finish = (request: Pending) => {
+      if (!pending.delete(request))
+        return false
+      if (request.timer !== undefined)
+        clearTimeout(request.timer)
+      if (request.id !== undefined)
+        delete host.promises[request.id]
+      if (!pending.size)
+        requests.delete(host)
+      return true
+    }
+    const request: Pending = {
+      callbacks: {
+        resove(value) {
+          if (finish(request))
+            resolve(value)
+        },
+        reject(error) {
+          if (finish(request))
+            reject(error)
+        },
+      },
+    }
+    pending.add(request)
+    const loop = () => {
+      request.timer = undefined
+      if (!pending.has(request))
+        return
+      if (host.destroyed) {
+        request.callbacks.reject(new Error('The instance has been destroyed'))
+        return
+      }
+      try {
+        if (host.injected) {
+          const id = Math.max(Date.now(), lastId + 1)
+          lastId = id
+          request.id = id
+          host.promises[id] = request.callbacks
+          host.$iframe.contentWindow!.postMessage({ type, data, id }, '*')
+        }
+        else {
+          request.timer = setTimeout(loop, 200)
+        }
+      }
+      catch (error) {
+        request.callbacks.reject(error)
+      }
+    }
+    loop()
+  })
+}
+
+export function cancelRequests(host: RequestHost): void {
+  const pending = requests.get(host)
+  if (!pending)
+    return
+  for (const request of [...pending])
+    request.callbacks.reject(new Error('The instance has been destroyed'))
+}