[ServiceWorker] Allow waitUntil to be called multiple times asynchronously

third_party/WebKit/Source/modules/serviceworkers/WaitUntilObserver.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WaitUntilObserver_h
 #define WaitUntilObserver_h
 
 #include "modules/ModulesExport.h"
 #include "modules/serviceworkers/ServiceWorkerGlobalScopeClient.h"
 #include "platform/Timer.h"
 #include "platform/wtf/Forward.h"
+#include "platform/wtf/Functional.h"
 
 namespace blink {
 
 class ExceptionState;
 class ExecutionContext;
 class ScriptPromise;
 class ScriptState;
 
 // Created for each ExtendableEvent instance.
 class MODULES_EXPORT WaitUntilObserver final
     : public GarbageCollectedFinalized<WaitUntilObserver> {
  public:
+  using PromiseSettledCallback = Function<void(const ScriptValue&)>;
+
   enum EventType {
     kActivate,
     kFetch,
     kInstall,
     kMessage,
     kNotificationClick,
     kNotificationClose,
     kPaymentRequest,
     kPush,
     kSync,
     kBackgroundFetchAbort,
     kBackgroundFetchClick,
     kBackgroundFetchFail,
     kBackgroundFetched
   };
 
   static WaitUntilObserver* Create(ExecutionContext*, EventType, int event_id);
 
   // Must be called before dispatching the event.
   void WillDispatchEvent();
   // Must be called after dispatching the event. If |event_dispatch_failed| is
   // true, then DidDispatchEvent() immediately reports to
   // ServiceWorkerGlobalScopeClient that the event finished, without waiting for
   // all waitUntil promises to settle.
   void DidDispatchEvent(bool event_dispatch_failed);
 
-  // Observes the promise and delays calling the continuation until
-  // the given promise is resolved or rejected.
-  void WaitUntil(ScriptState*, ScriptPromise, ExceptionState&);
-
-  // These methods can be called when the lifecycle of ExtendableEvent
-  // observed by this WaitUntilObserver should be extended by other reason
-  // than ExtendableEvent.waitUntil.
-  // Note: There is no need to call decrementPendingActivity() after the context
-  // is being destroyed.
-  void IncrementPendingActivity();
-  void DecrementPendingActivity();
+  // Observes the promise and delays reporting to ServiceWorkerGlobalScopeClient
+  // that the event completed until the given promise is resolved or rejected.
+  // WaitUntil may be called multiple times. The event is extended until all
+  // promises have settled.
+  // If provided, |on_promise_fulfilled| or |on_promise_rejected| is invoked
+  // once |script_promise| fulfills or rejects. This enables the caller to do
+  // custom handling.
+  void WaitUntil(
+      ScriptState*,
+      ScriptPromise /* script_promise */,
+      ExceptionState&,
+      std::unique_ptr<PromiseSettledCallback> on_promise_fulfilled = nullptr,
+      std::unique_ptr<PromiseSettledCallback> on_promise_rejected = nullptr);
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   friend class InternalsServiceWorker;
   class ThenFunction;
 
   enum class EventDispatchState {
-    // Event dispatch has not yet finished.
+    // Event dispatch has not yet started.
     kInitial,
+    // Event dispatch has started but not yet finished.
+    kDispatching,
     // Event dispatch completed. There may still be outstanding waitUntil
     // promises that must settle before notifying ServiceWorkerGlobalScopeClient
     // that the event finished.
-    kCompleted,
+    kDispatched,
     // Event dispatch failed. Any outstanding waitUntil promises are ignored.
     kFailed
   };
 
   WaitUntilObserver(ExecutionContext*, EventType, int event_id);
 
-  // Called when a promise passed to a waitUntil() call that is associated with
-  // this observer was fulfilled.
+  void IncrementPendingPromiseCount();
+  void DecrementPendingPromiseCount();
+
+  // Enqueued as a microtask when a promise passed to a waitUntil() call that is
+  // associated with this observer was fulfilled.
   void OnPromiseFulfilled();
-  // Called when a promise passed to a waitUntil() call that is associated with
-  // this observer was rejected.
+  // Enqueued as a microtask when a promise passed to a waitUntil() call that is
+  // associated with this observer was rejected.
   void OnPromiseRejected();
 
   void ConsumeWindowInteraction(TimerBase*);
 
+  void MaybeCompleteEvent();
+
   Member<ExecutionContext> execution_context_;
   EventType type_;
   int event_id_;
-  int pending_activity_ = 0;
+  int pending_promises_ = 0;
   EventDispatchState event_dispatch_state_ = EventDispatchState::kInitial;
   bool has_rejected_promise_ = false;
   double event_dispatch_time_ = 0;
   TaskRunnerTimer<WaitUntilObserver> consume_window_interaction_timer_;
 };
 
 }  // namespace blink
 
 #endif  // WaitUntilObserver_h