| // Copyright 2016 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 CONTENT_RENDERER_INPUT_MAIN_THREAD_EVENT_QUEUE_H_ |
| #define CONTENT_RENDERER_INPUT_MAIN_THREAD_EVENT_QUEUE_H_ |
| |
| #include <deque> |
| #include "content/common/content_export.h" |
| #include "content/common/input/event_with_latency_info.h" |
| #include "content/common/input/input_event_ack_state.h" |
| #include "content/common/input/input_event_dispatch_type.h" |
| #include "content/common/input/web_input_event_queue.h" |
| #include "third_party/WebKit/public/web/WebInputEvent.h" |
| #include "ui/events/latency_info.h" |
| |
| namespace content { |
| |
| template <typename BaseClass, typename BaseType> |
| class EventWithDispatchType : public BaseClass { |
| public: |
| EventWithDispatchType(const BaseType& e, |
| const ui::LatencyInfo& l, |
| InputEventDispatchType t) |
| : BaseClass(e, l), type(t) {} |
| |
| InputEventDispatchType type; |
| |
| bool CanCoalesceWith(const EventWithDispatchType& other) const |
| WARN_UNUSED_RESULT { |
| return other.type == type && BaseClass::CanCoalesceWith(other); |
| } |
| |
| void CoalesceWith(const EventWithDispatchType& other) { |
| BaseClass::CoalesceWith(other); |
| } |
| }; |
| |
| using PendingMouseWheelEvent = |
| EventWithDispatchType<MouseWheelEventWithLatencyInfo, |
| blink::WebMouseWheelEvent>; |
| |
| using PendingTouchEvent = |
| EventWithDispatchType<TouchEventWithLatencyInfo, blink::WebTouchEvent>; |
| |
| class CONTENT_EXPORT MainThreadEventQueueClient { |
| public: |
| // Send an |event| that was previously queued (possibly |
| // coalesced with another event) to the |routing_id|'s |
| // channel. Implementors must implement this callback. |
| virtual void SendEventToMainThread(int routing_id, |
| const blink::WebInputEvent* event, |
| const ui::LatencyInfo& latency, |
| InputEventDispatchType dispatch_type) = 0; |
| }; |
| |
| // MainThreadEventQueue implements a series of queues (one touch |
| // and one mouse wheel) for events that need to be queued between |
| // the compositor and main threads. When an event is sent |
| // from the compositor to main it can either be sent directly if no |
| // outstanding events of that type are in flight; or it needs to |
| // wait in a queue until the main thread has finished processing |
| // the in-flight event. This class tracks the state and queues |
| // for the event types. Methods on this class should only be called |
| // from the compositor thread. |
| // |
| // Below some example flows are how the code behaves. |
| // Legend: B=Browser, C=Compositor, M=Main Thread, NB=Non-blocking |
| // BL=Blocking, PT=Post Task, ACK=Acknowledgement |
| // |
| // Normal blocking event sent to main thread. |
| // B C M |
| // ---(BL)--> |
| // ---(PT)--> |
| // <-------(ACK)------ |
| // |
| // Non-blocking event sent to main thread. |
| // B C M |
| // ---(NB)--> |
| // ---(PT)--> |
| // <--(PT)--- |
| // |
| // Non-blocking followed by blocking event sent to main thread. |
| // B C M |
| // ---(NB)--> |
| // ---(PT)--> |
| // ---(BL)--> |
| // <--(PT)--- // Notify from NB event. |
| // ---(PT)--> // Release blocking event. |
| // <--(PT)--- // Notify from BL event. |
| // <-------(ACK)------ |
| // |
| class CONTENT_EXPORT MainThreadEventQueue { |
| public: |
| MainThreadEventQueue(int routing_id, MainThreadEventQueueClient* client); |
| ~MainThreadEventQueue(); |
| |
| // Called once the compositor has handled |event| and indicated that it is |
| // a non-blocking event to be queued to the main thread. |
| bool HandleEvent(const blink::WebInputEvent* event, |
| const ui::LatencyInfo& latency, |
| InputEventDispatchType dispatch_type, |
| InputEventAckState ack_result); |
| |
| // Call once the main thread has handled an outstanding |type| event |
| // in flight. |
| void EventHandled(blink::WebInputEvent::Type type); |
| |
| private: |
| friend class MainThreadEventQueueTest; |
| int routing_id_; |
| MainThreadEventQueueClient* client_; |
| WebInputEventQueue<PendingMouseWheelEvent> wheel_events_; |
| WebInputEventQueue<PendingTouchEvent> touch_events_; |
| |
| DISALLOW_COPY_AND_ASSIGN(MainThreadEventQueue); |
| }; |
| |
| } // namespace content |
| |
| #endif // CONTENT_RENDERER_INPUT_MAIN_THREAD_EVENT_QUEUE_H_ |