content/renderer/input/input_handler_proxy.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_RENDERER_INPUT_INPUT_HANDLER_PROXY_H_
   6 #define CONTENT_RENDERER_INPUT_INPUT_HANDLER_PROXY_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/containers/hash_tables.h"
  10 #include "base/gtest_prod_util.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "cc/input/input_handler.h"
  13 #include "content/common/content_export.h"
  14 #include "third_party/WebKit/public/platform/WebGestureCurve.h"
  15 #include "third_party/WebKit/public/platform/WebGestureCurveTarget.h"
  16 #include "third_party/WebKit/public/web/WebActiveWheelFlingParameters.h"
  17 #include "third_party/WebKit/public/web/WebInputEvent.h"
  18
  19 namespace content {
  20
  21 class InputHandlerProxyClient;
  22 class InputScrollElasticityController;
  23
  24 // This class is a proxy between the content input event filtering and the
  25 // compositor's input handling logic. InputHandlerProxy instances live entirely
  26 // on the compositor thread. Each InputHandler instance handles input events
  27 // intended for a specific WebWidget.
  28 class CONTENT_EXPORT InputHandlerProxy
  29     : public cc::InputHandlerClient,
  30       public NON_EXPORTED_BASE(blink::WebGestureCurveTarget) {
  31  public:
  32   InputHandlerProxy(cc::InputHandler* input_handler,
  33                     InputHandlerProxyClient* client);
  34   virtual ~InputHandlerProxy();
  35
  36   InputScrollElasticityController* scroll_elasticity_controller() {
  37     return scroll_elasticity_controller_.get();
  38   }
  39
  40   enum EventDisposition {
  41     DID_HANDLE,
  42     DID_NOT_HANDLE,
  43     DROP_EVENT
  44   };
  45   EventDisposition HandleInputEventWithLatencyInfo(
  46       const blink::WebInputEvent& event,
  47       ui::LatencyInfo* latency_info);
  48   EventDisposition HandleInputEvent(const blink::WebInputEvent& event);
  49
  50   // cc::InputHandlerClient implementation.
  51   void WillShutdown() override;
  52   void Animate(base::TimeTicks time) override;
  53   void MainThreadHasStoppedFlinging() override;
  54   void ReconcileElasticOverscrollAndRootScroll() override;
  55
  56   // blink::WebGestureCurveTarget implementation.
  57   virtual bool scrollBy(const blink::WebFloatSize& offset,
  58                         const blink::WebFloatSize& velocity);
  59
  60   bool gesture_scroll_on_impl_thread_for_testing() const {
  61     return gesture_scroll_on_impl_thread_;
  62   }
  63
  64  private:
  65   // Helper functions for handling more complicated input events.
  66   EventDisposition HandleMouseWheel(
  67       const blink::WebMouseWheelEvent& event);
  68   EventDisposition HandleGestureScrollBegin(
  69       const blink::WebGestureEvent& event);
  70   EventDisposition HandleGestureScrollUpdate(
  71       const blink::WebGestureEvent& event);
  72   EventDisposition HandleGestureScrollEnd(
  73       const blink::WebGestureEvent& event);
  74   EventDisposition HandleGestureFlingStart(
  75       const blink::WebGestureEvent& event);
  76   EventDisposition HandleTouchStart(
  77       const blink::WebTouchEvent& event);
  78
  79   // Returns true if the event should be suppressed due to to an active,
  80   // boost-enabled fling, in which case further processing should cease.
  81   bool FilterInputEventForFlingBoosting(const blink::WebInputEvent& event);
  82
  83   // Schedule a time in the future after which a boost-enabled fling will
  84   // terminate without further momentum from the user (see |Animate()|).
  85   void ExtendBoostedFlingTimeout(const blink::WebGestureEvent& event);
  86
  87   // Returns true if we scrolled by the increment.
  88   bool TouchpadFlingScroll(const blink::WebFloatSize& increment);
  89
  90   // Returns true if we actually had an active fling to cancel, also notifying
  91   // the client that the fling has ended. Note that if a boosted fling is active
  92   // and suppressing an active scroll sequence, a synthetic GestureScrollBegin
  93   // will be injected to resume scrolling.
  94   bool CancelCurrentFling();
  95
  96   // Returns true if we actually had an active fling to cancel.
  97   bool CancelCurrentFlingWithoutNotifyingClient();
  98
  99   // Used to send overscroll messages to the browser.
 100   void HandleOverscroll(
 101       const gfx::Point& causal_event_viewport_point,
 102       const cc::InputHandlerScrollResult& scroll_result);
 103
 104   scoped_ptr<blink::WebGestureCurve> fling_curve_;
 105   // Parameters for the active fling animation, stored in case we need to
 106   // transfer it out later.
 107   blink::WebActiveWheelFlingParameters fling_parameters_;
 108
 109   InputHandlerProxyClient* client_;
 110   cc::InputHandler* input_handler_;
 111
 112   // Time at which an active fling should expire due to a deferred cancellation
 113   // event. A call to |Animate()| after this time will end the fling.
 114   double deferred_fling_cancel_time_seconds_;
 115
 116   // The last event that extended the lifetime of the boosted fling. If the
 117   // event was a scroll gesture, a GestureScrollBegin will be inserted if the
 118   // fling terminates (via |CancelCurrentFling()|).
 119   blink::WebGestureEvent last_fling_boost_event_;
 120
 121 #ifndef NDEBUG
 122   bool expect_scroll_update_end_;
 123 #endif
 124   bool gesture_scroll_on_impl_thread_;
 125   bool gesture_pinch_on_impl_thread_;
 126   // This is always false when there are no flings on the main thread, but
 127   // conservative in the sense that we might not be actually flinging when it is
 128   // true.
 129   bool fling_may_be_active_on_main_thread_;
 130   // The axes on which the current fling is allowed to scroll.  If a given fling
 131   // has overscrolled on a particular axis, further fling scrolls on that axis
 132   // will be disabled.
 133   bool disallow_horizontal_fling_scroll_;
 134   bool disallow_vertical_fling_scroll_;
 135
 136   // Whether an active fling has seen an |Animate()| call. This is useful for
 137   // determining if the fling start time should be re-initialized.
 138   bool has_fling_animation_started_;
 139
 140   // Non-zero only within the scope of |scrollBy|.
 141   gfx::Vector2dF current_fling_velocity_;
 142
 143   // Used to animate rubber-band over-scroll effect on Mac.
 144   scoped_ptr<InputScrollElasticityController> scroll_elasticity_controller_;
 145
 146   bool smooth_scroll_enabled_;
 147
 148   bool uma_latency_reporting_enabled_;
 149
 150   DISALLOW_COPY_AND_ASSIGN(InputHandlerProxy);
 151 };
 152
 153 }  // namespace content
 154
 155 #endif  // CONTENT_RENDERER_INPUT_INPUT_HANDLER_PROXY_H_