| // 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 THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_PLATFORM_EVENT_DISPATCHER_H_ |
| #define THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_PLATFORM_EVENT_DISPATCHER_H_ |
| |
| #include "third_party/blink/renderer/core/core_export.h" |
| #include "third_party/blink/renderer/platform/heap/handle.h" |
| |
| namespace blink { |
| class PlatformEventController; |
| class LocalFrame; |
| |
| class CORE_EXPORT PlatformEventDispatcher : public GarbageCollectedMixin { |
| public: |
| // Adds a controller to be notified when a change event occurs and starts |
| // listening for change events. |frame| is the frame that will be passed to |
| // the dispatcher's StartListening method. The caller must provide a valid, |
| // non-nullptr frame. |
| // |
| // Note that the frame associated with the controller's document may be |
| // nullptr if the document was shut down, which can occur when a frame |
| // navigates from an initial empty document to another same-origin document. |
| // If the controller was initialized with the initial empty document, it may |
| // need to provide a valid frame from another source, for instance the |
| // DOMWindow. |
| // TODO(crbug.com/850619): fix all the callsites, currently not all of them |
| // (and unittests) are guaranteed to pass a non-nullptr frame. |
| void AddController(PlatformEventController*, LocalFrame* frame); |
| |
| // Removes a controller from |controllers_| and stops listening if there are |
| // no more registered controllers. |
| void RemoveController(PlatformEventController*); |
| |
| void Trace(blink::Visitor*) override; |
| |
| protected: |
| PlatformEventDispatcher(); |
| |
| void NotifyControllers(); |
| |
| virtual void StartListening(LocalFrame* frame) = 0; |
| virtual void StopListening() = 0; |
| |
| private: |
| void PurgeControllers(); |
| |
| HeapHashSet<WeakMember<PlatformEventController>> controllers_; |
| bool is_dispatching_; |
| bool is_listening_; |
| }; |
| |
| } // namespace blink |
| |
| #endif // THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_PLATFORM_EVENT_DISPATCHER_H_ |