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   void WillShutdown() override;
  46   void Animate(base::TimeTicks time) override;
  47   void MainThreadHasStoppedFlinging() override;
  48   void DidOverscroll(const gfx::PointF& causal_event_viewport_point,
  49                      const gfx::Vector2dF& accumulated_overscroll,
  50                      const gfx::Vector2dF& latest_overscroll_delta) override;
  51
  52   // blink::WebGestureCurveTarget implementation.
  53   virtual bool scrollBy(const blink::WebFloatSize& offset,
  54                         const blink::WebFloatSize& velocity);
  55
  56   bool gesture_scroll_on_impl_thread_for_testing() const {
  57     return gesture_scroll_on_impl_thread_;
  58   }
  59
  60  private:
  61   EventDisposition HandleGestureFling(const blink::WebGestureEvent& event);
  62
  63   // Returns true if the event should be suppressed due to to an active,
  64   // boost-enabled fling, in which case further processing should cease.
  65   bool FilterInputEventForFlingBoosting(const blink::WebInputEvent& event);
  66
  67   // Schedule a time in the future after which a boost-enabled fling will
  68   // terminate without further momentum from the user (see |Animate()|).
  69   void ExtendBoostedFlingTimeout(const blink::WebGestureEvent& event);
  70
  71   // Returns true if we scrolled by the increment.
  72   bool TouchpadFlingScroll(const blink::WebFloatSize& increment);
  73
  74   // Returns true if we actually had an active fling to cancel, also notifying
  75   // the client that the fling has ended. Note that if a boosted fling is active
  76   // and suppressing an active scroll sequence, a synthetic GestureScrollBegin
  77   // will be injected to resume scrolling.
  78   bool CancelCurrentFling();
  79
  80   // Returns true if we actually had an active fling to cancel.
  81   bool CancelCurrentFlingWithoutNotifyingClient();
  82
  83   scoped_ptr<blink::WebGestureCurve> fling_curve_;
  84   // Parameters for the active fling animation, stored in case we need to
  85   // transfer it out later.
  86   blink::WebActiveWheelFlingParameters fling_parameters_;
  87
  88   InputHandlerProxyClient* client_;
  89   cc::InputHandler* input_handler_;
  90
  91   // Time at which an active fling should expire due to a deferred cancellation
  92   // event. A call to |Animate()| after this time will end the fling.
  93   double deferred_fling_cancel_time_seconds_;
  94
  95   // The last event that extended the lifetime of the boosted fling. If the
  96   // event was a scroll gesture, a GestureScrollBegin will be inserted if the
  97   // fling terminates (via |CancelCurrentFling()|).
  98   blink::WebGestureEvent last_fling_boost_event_;
  99
 100 #ifndef NDEBUG
 101   bool expect_scroll_update_end_;
 102 #endif
 103   bool gesture_scroll_on_impl_thread_;
 104   bool gesture_pinch_on_impl_thread_;
 105   // This is always false when there are no flings on the main thread, but
 106   // conservative in the sense that we might not be actually flinging when it is
 107   // true.
 108   bool fling_may_be_active_on_main_thread_;
 109   // The axes on which the current fling is allowed to scroll.  If a given fling
 110   // has overscrolled on a particular axis, further fling scrolls on that axis
 111   // will be disabled.
 112   bool disallow_horizontal_fling_scroll_;
 113   bool disallow_vertical_fling_scroll_;
 114
 115   // Whether an active fling has seen an |Animate()| call. This is useful for
 116   // determining if the fling start time should be re-initialized.
 117   bool has_fling_animation_started_;
 118
 119   // Non-zero only within the scope of |scrollBy|.
 120   gfx::Vector2dF current_fling_velocity_;
 121
 122   bool smooth_scroll_enabled_;
 123
 124   DISALLOW_COPY_AND_ASSIGN(InputHandlerProxy);
 125 };
 126
 127 }  // namespace content
 128
 129 #endif  // CONTENT_RENDERER_INPUT_INPUT_HANDLER_PROXY_H_