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/memory/scoped_ptr.h"
  11 #include "cc/input/input_handler.h"
  12 #include "content/common/content_export.h"
  13 #include "third_party/WebKit/public/platform/WebGestureCurve.h"
  14 #include "third_party/WebKit/public/platform/WebGestureCurveTarget.h"
  15 #include "third_party/WebKit/public/web/WebActiveWheelFlingParameters.h"
  16 #include "third_party/WebKit/public/web/WebInputEvent.h"
  17
  18 namespace content {
  19
  20 class InputHandlerProxyClient;
  21
  22 // This class is a proxy between the content input event filtering and the
  23 // compositor's input handling logic. InputHandlerProxy instances live entirely
  24 // on the compositor thread. Each InputHandler instance handles input events
  25 // intended for a specific WebWidget.
  26 class CONTENT_EXPORT InputHandlerProxy
  27     : public cc::InputHandlerClient,
  28       public NON_EXPORTED_BASE(blink::WebGestureCurveTarget) {
  29  public:
  30   InputHandlerProxy(cc::InputHandler* input_handler,
  31                     InputHandlerProxyClient* client);
  32   virtual ~InputHandlerProxy();
  33
  34   enum EventDisposition {
  35     DID_HANDLE,
  36     DID_NOT_HANDLE,
  37     DROP_EVENT
  38   };
  39   EventDisposition HandleInputEventWithLatencyInfo(
  40       const blink::WebInputEvent& event,
  41       ui::LatencyInfo* latency_info);
  42   EventDisposition HandleInputEvent(const blink::WebInputEvent& event);
  43
  44   // cc::InputHandlerClient implementation.
  45   virtual void WillShutdown() override;
  46   virtual void Animate(base::TimeTicks time) override;
  47   virtual void MainThreadHasStoppedFlinging() override;
  48   virtual void DidOverscroll(
  49       const gfx::PointF& causal_event_viewport_point,
  50       const gfx::Vector2dF& accumulated_overscroll,
  51       const gfx::Vector2dF& latest_overscroll_delta) override;
  52
  53   // blink::WebGestureCurveTarget implementation.
  54   virtual bool scrollBy(const blink::WebFloatSize& offset,
  55                         const blink::WebFloatSize& velocity);
  56
  57   bool gesture_scroll_on_impl_thread_for_testing() const {
  58     return gesture_scroll_on_impl_thread_;
  59   }
  60
  61  private:
  62   EventDisposition HandleGestureFling(const blink::WebGestureEvent& event);
  63
  64   // Returns true if the event should be suppressed due to to an active,
  65   // boost-enabled fling, in which case further processing should cease.
  66   bool FilterInputEventForFlingBoosting(const blink::WebInputEvent& event);
  67
  68   // Schedule a time in the future after which a boost-enabled fling will
  69   // terminate without further momentum from the user (see |Animate()|).
  70   void ExtendBoostedFlingTimeout(const blink::WebGestureEvent& event);
  71
  72   // Returns true if we scrolled by the increment.
  73   bool TouchpadFlingScroll(const blink::WebFloatSize& increment);
  74
  75   // Returns true if we actually had an active fling to cancel, also notifying
  76   // the client that the fling has ended. Note that if a boosted fling is active
  77   // and suppressing an active scroll sequence, a synthetic GestureScrollBegin
  78   // will be injected to resume scrolling.
  79   bool CancelCurrentFling();
  80
  81   // Returns true if we actually had an active fling to cancel.
  82   bool CancelCurrentFlingWithoutNotifyingClient();
  83
  84   scoped_ptr<blink::WebGestureCurve> fling_curve_;
  85   // Parameters for the active fling animation, stored in case we need to
  86   // transfer it out later.
  87   blink::WebActiveWheelFlingParameters fling_parameters_;
  88
  89   InputHandlerProxyClient* client_;
  90   cc::InputHandler* input_handler_;
  91
  92   // Time at which an active fling should expire due to a deferred cancellation
  93   // event. A call to |Animate()| after this time will end the fling.
  94   double deferred_fling_cancel_time_seconds_;
  95
  96   // The last event that extended the lifetime of the boosted fling. If the
  97   // event was a scroll gesture, a GestureScrollBegin will be inserted if the
  98   // fling terminates (via |CancelCurrentFling()|).
  99   blink::WebGestureEvent last_fling_boost_event_;
 100
 101 #ifndef NDEBUG
 102   bool expect_scroll_update_end_;
 103 #endif
 104   bool gesture_scroll_on_impl_thread_;
 105   bool gesture_pinch_on_impl_thread_;
 106   // This is always false when there are no flings on the main thread, but
 107   // conservative in the sense that we might not be actually flinging when it is
 108   // true.
 109   bool fling_may_be_active_on_main_thread_;
 110   // The axes on which the current fling is allowed to scroll.  If a given fling
 111   // has overscrolled on a particular axis, further fling scrolls on that axis
 112   // will be disabled.
 113   bool disallow_horizontal_fling_scroll_;
 114   bool disallow_vertical_fling_scroll_;
 115
 116   // Whether an active fling has seen an |Animate()| call. This is useful for
 117   // determining if the fling start time should be re-initialized.
 118   bool has_fling_animation_started_;
 119
 120   // Non-zero only within the scope of |scrollBy|.
 121   gfx::Vector2dF current_fling_velocity_;
 122
 123   bool smooth_scroll_enabled_;
 124
 125   DISALLOW_COPY_AND_ASSIGN(InputHandlerProxy);
 126 };
 127
 128 }  // namespace content
 129
 130 #endif  // CONTENT_RENDERER_INPUT_INPUT_HANDLER_PROXY_H_