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// Copyright 2018 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_BROWSER_RENDERER_HOST_INPUT_TOUCHPAD_PINCH_EVENT_QUEUE_H_
#define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCHPAD_PINCH_EVENT_QUEUE_H_
#include <memory>
#include "base/containers/circular_deque.h"
#include "base/optional.h"
#include "content/common/content_export.h"
#include "content/common/input/event_with_latency_info.h"
#include "content/public/common/input_event_ack_source.h"
#include "content/public/common/input_event_ack_state.h"
#include "third_party/blink/public/platform/web_input_event.h"
namespace ui {
class LatencyInfo;
} // namespace ui
namespace content {
class QueuedTouchpadPinchEvent;
// Interface with which TouchpadPinchEventQueue can forward synthetic mouse
// wheel events and notify of pinch events.
class CONTENT_EXPORT TouchpadPinchEventQueueClient {
public:
virtual ~TouchpadPinchEventQueueClient() = default;
virtual void SendMouseWheelEventForPinchImmediately(
const MouseWheelEventWithLatencyInfo& event) = 0;
virtual void OnGestureEventForPinchAck(
const GestureEventWithLatencyInfo& event,
InputEventAckSource ack_source,
InputEventAckState ack_result) = 0;
};
// A queue for sending synthetic mouse wheel events for touchpad pinches.
// In order for a page to prevent touchpad pinch zooming, we send synthetic
// wheel events which may be cancelled. Once we've determined whether a page
// has prevented the pinch, the TouchpadPinchEventQueueClient may proceed with
// handling the pinch.
// See README.md for further details.
class CONTENT_EXPORT TouchpadPinchEventQueue {
public:
// The |client| must outlive the TouchpadPinchEventQueue.
TouchpadPinchEventQueue(TouchpadPinchEventQueueClient* client);
~TouchpadPinchEventQueue();
// Adds the given touchpad pinch |event| to the queue. The event may be
// coalesced with previously queued events.
void QueueEvent(const GestureEventWithLatencyInfo& event);
// Notifies the queue that a synthetic mouse wheel event has been processed
// by the renderer.
void ProcessMouseWheelAck(InputEventAckSource ack_source,
InputEventAckState ack_result,
const ui::LatencyInfo& latency_info);
bool has_pending() const WARN_UNUSED_RESULT;
private:
void TryForwardNextEventToRenderer();
const bool touchpad_async_pinch_events_;
TouchpadPinchEventQueueClient* client_;
base::circular_deque<std::unique_ptr<QueuedTouchpadPinchEvent>> pinch_queue_;
std::unique_ptr<QueuedTouchpadPinchEvent> pinch_event_awaiting_ack_;
base::Optional<bool> first_event_prevented_;
DISALLOW_COPY_AND_ASSIGN(TouchpadPinchEventQueue);
};
} // namespace content
#endif // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCHPAD_PINCH_EVENT_QUEUE_H_
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