Support GestureBegin and GestureEnd in ui::GestureProvider

ui/events/gesture_detection/gesture_provider.cc

 // Copyright 2014 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.
 
 #include "ui/events/gesture_detection/gesture_provider.h"
 
 #include <cmath>
 
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
@@ skipping 58 matching lines @@
   GestureEventDetails tap_details(type, 1, 0);
   tap_details.set_bounding_box(
       gfx::RectF(event.GetTouchMajor(), event.GetTouchMajor()));
   return tap_details;
 }
 
 }  // namespace
 
 // GestureProvider:::Config
 
-GestureProvider::Config::Config() : disable_click_delay(false) {}
+GestureProvider::Config::Config()
+    : disable_click_delay(false), gesture_begin_end_types_enabled(false) {}
 
 GestureProvider::Config::~Config() {}
 
 // GestureProvider::ScaleGestureListener
 
 class GestureProvider::ScaleGestureListenerImpl
     : public ScaleGestureDetector::ScaleGestureListener {
  public:
   ScaleGestureListenerImpl(const ScaleGestureDetector::Config& config,
                            GestureProvider* provider)
@@ skipping 507 matching lines @@
 };
 
 // GestureProvider
 
 GestureProvider::GestureProvider(const Config& config,
                                  GestureProviderClient* client)
     : client_(client),
       needs_show_press_event_(false),
       needs_tap_ending_event_(false),
       touch_scroll_in_progress_(false),
-      pinch_in_progress_(false) {
+      pinch_in_progress_(false),
+      gesture_begin_end_types_enabled_(false) {

[jdduke (slow), 2014/04/03 22:03:28]

gesture_begin_end_types_enabled_(config.gesture_begin_end_types_enabled) {

The double-tap/multi-touch toggles can all occur at different points in the
provider lifetime, so we need explicit setters, but this flag should be set only
once.

[tdresser, 2014/04/04 16:39:31]

Done.

   DCHECK(client);
   InitGestureDetectors(config);
 }
 
 GestureProvider::~GestureProvider() {}
 
 bool GestureProvider::OnTouchEvent(const MotionEvent& event) {
   TRACE_EVENT1("input", "GestureProvider::OnTouchEvent",
                "action", GetMotionEventActionName(event.GetAction()));
   if (!CanHandle(event))
     return false;
 
-  const bool was_touch_scrolling_ = touch_scroll_in_progress_;
+  OnTouchEventHandlingBegin(event);
+
+  const bool was_touch_scrolling = touch_scroll_in_progress_;
   const bool in_scale_gesture =
       scale_gesture_listener_->IsScaleGestureDetectionInProgress();
 
-  if (event.GetAction() == MotionEvent::ACTION_DOWN) {
-    current_down_event_ = event.Clone();
-    touch_scroll_in_progress_ = false;
-    needs_show_press_event_ = true;
-    current_longpress_time_ = base::TimeTicks();
-    SendTapCancelIfNecessary(event);
-  }
 
   bool handled = gesture_listener_->OnTouchEvent(event, in_scale_gesture);

[jdduke (slow), 2014/04/03 22:03:28]

I guess we'll no longer need the |handled| variable (see below).

[tdresser, 2014/04/04 16:39:31]

Done.

   handled |= scale_gesture_listener_->OnTouchEvent(event);
 
-  if (event.GetAction() == MotionEvent::ACTION_UP ||
-      event.GetAction() == MotionEvent::ACTION_CANCEL) {
-    // "Last finger raised" could be an end to movement, but it should
-    // only terminate scrolling if the event did not cause a fling.
-    if (was_touch_scrolling_ && !handled)
-      EndTouchScrollIfNecessary(event.GetEventTime(), true);
-
-    // We shouldn't necessarily cancel a tap on ACTION_UP, as the double-tap
-    // timeout may yet trigger a SINGLE_TAP.
-    if (event.GetAction() == MotionEvent::ACTION_CANCEL)
-      SendTapCancelIfNecessary(event);
-
-    current_down_event_.reset();
-  }
+  OnTouchEventHandlingEnd(event, handled, was_touch_scrolling);
 
   return true;
 }
 
 void GestureProvider::ResetGestureDetectors() {
   if (!current_down_event_)
     return;
   scoped_ptr<MotionEvent> cancel_event = current_down_event_->Cancel();
   gesture_listener_->OnTouchEvent(*cancel_event, false);
   scale_gesture_listener_->OnTouchEvent(*cancel_event);
 }
 
 void GestureProvider::SetMultiTouchSupportEnabled(bool enabled) {
   scale_gesture_listener_->set_ignore_detector_events(!enabled);
 }
 
 void GestureProvider::SetDoubleTapSupportForPlatformEnabled(bool enabled) {
   gesture_listener_->SetDoubleTapSupportForPlatformEnabled(enabled);
 }
 
 void GestureProvider::SetDoubleTapSupportForPageEnabled(bool enabled) {
   gesture_listener_->SetDoubleTapSupportForPageEnabled(enabled);
 }
 
+void GestureProvider::SetBeginEndTypesEnabled(bool enabled) {
+  gesture_begin_end_types_enabled_ = enabled;
+}
+
 bool GestureProvider::IsScrollInProgress() const {
   // TODO(wangxianzhu): Also return true when fling is active once the UI knows
   // exactly when the fling ends.
   return touch_scroll_in_progress_;
 }
 
 bool GestureProvider::IsPinchInProgress() const { return pinch_in_progress_; }
 
 bool GestureProvider::IsDoubleTapInProgress() const {
   return gesture_listener_->IsDoubleTapInProgress();
 }
 
 bool GestureProvider::IsClickDelayDisabled() const {
   return gesture_listener_->IsClickDelayDisabled();
 }
 
 void GestureProvider::InitGestureDetectors(const Config& config) {
   TRACE_EVENT0("input", "GestureProvider::InitGestureDetectors");
   gesture_listener_.reset(
       new GestureListenerImpl(config.gesture_detector_config,
                               config.snap_scroll_controller_config,
                               config.disable_click_delay,
                               this));
 
   scale_gesture_listener_.reset(
       new ScaleGestureListenerImpl(config.scale_gesture_detector_config, this));
+  gesture_begin_end_types_enabled_ = config.gesture_begin_end_types_enabled;
 }
 
 bool GestureProvider::CanHandle(const MotionEvent& event) const {
   return event.GetAction() == MotionEvent::ACTION_DOWN || current_down_event_;
 }
 
 void GestureProvider::Fling(base::TimeTicks time,
                             float x,
                             float y,
                             float velocity_x,
@@ skipping 18 matching lines @@
       ET_SCROLL_FLING_START, velocity_x, velocity_y);
   Send(CreateGesture(ET_SCROLL_FLING_START, time, x, y, fling_details));
 }
 
 void GestureProvider::Send(const GestureEventData& gesture) {
   DCHECK(!gesture.time.is_null());
   // The only valid events that should be sent without an active touch sequence
   // are SHOW_PRESS and TAP, potentially triggered by the double-tap
   // delay timing out.
   DCHECK(current_down_event_ || gesture.type == ET_GESTURE_TAP ||
-         gesture.type == ET_GESTURE_SHOW_PRESS);
+         gesture.type == ET_GESTURE_SHOW_PRESS ||
+         gesture.type == ET_GESTURE_BEGIN || gesture.type == ET_GESTURE_END);

[jdduke (slow), 2014/04/03 22:03:28]

If we send GESTURE_END before resetting the down event in
OnTouchEventHandlingEnd, we shouldn't need these extra exceptions.

[tdresser, 2014/04/04 16:39:31]

Done.

 
   switch (gesture.type) {
     case ET_GESTURE_TAP_DOWN:
       needs_tap_ending_event_ = true;
       break;
     case ET_GESTURE_TAP_UNCONFIRMED:
       needs_show_press_event_ = false;
       break;
     case ET_GESTURE_TAP:
       if (needs_show_press_event_)
@@ skipping 63 matching lines @@
 
 void GestureProvider::EndTouchScrollIfNecessary(base::TimeTicks time,
                                                 bool send_scroll_end_event) {
   if (!touch_scroll_in_progress_)
     return;
   touch_scroll_in_progress_ = false;
   if (send_scroll_end_event)
     Send(CreateGesture(ET_GESTURE_SCROLL_END, time, 0, 0));
 }
 
+void GestureProvider::OnTouchEventHandlingBegin(const MotionEvent& event) {
+  switch (event.GetAction()) {
+    case MotionEvent::ACTION_DOWN:
+      current_down_event_ = event.Clone();
+      touch_scroll_in_progress_ = false;
+      needs_show_press_event_ = true;

[jdduke (slow), 2014/04/03 22:03:28]

Hmm, this show press assignment looks funky (pretty sure that's my bad).  Could
you change this to |needs_show_press_event_ = false;|, and then when we send a
TAP_DOWN set it to true?

[tdresser, 2014/04/04 16:39:31]

Done.

+      current_longpress_time_ = base::TimeTicks();
+      SendTapCancelIfNecessary(event);
+      if (gesture_begin_end_types_enabled_)
+        Send(CreateGesture(ET_GESTURE_BEGIN, event));
+      break;
+    case MotionEvent::ACTION_POINTER_DOWN:
+      if (gesture_begin_end_types_enabled_)
+        Send(CreateGesture(ET_GESTURE_BEGIN, event));
+      break;
+    case MotionEvent::ACTION_POINTER_UP:
+    case MotionEvent::ACTION_UP:
+    case MotionEvent::ACTION_CANCEL:
+    case MotionEvent::ACTION_MOVE:
+      break;
+  }
+}
+
+void GestureProvider::OnTouchEventHandlingEnd(
+    const MotionEvent& event, bool handled, bool was_touch_scrolling) {
+  switch (event.GetAction()) {
+    case MotionEvent::ACTION_UP:
+    case MotionEvent::ACTION_CANCEL:
+      // "Last finger raised" could be an end to movement, but it should
+      // only terminate scrolling if the event did not cause a fling.
+      if (was_touch_scrolling && !handled)
+        EndTouchScrollIfNecessary(event.GetEventTime(), true);

[jdduke (slow), 2014/04/03 22:03:28]

This will probably fail during rebase after
https://codereview.chromium.org/200623003/.  In short, you shouldn't need the
|handled| or |was_touch_scrolling| arguments.

[tdresser, 2014/04/04 16:39:31]

Done.

+
+      // We shouldn't necessarily cancel a tap on ACTION_UP, as the double-tap
+      // timeout may yet trigger a SINGLE_TAP.
+      if (event.GetAction() == MotionEvent::ACTION_CANCEL)
+        SendTapCancelIfNecessary(event);
+
+      current_down_event_.reset();
+      if (gesture_begin_end_types_enabled_)

[jdduke (slow), 2014/04/03 22:03:28]

This should come before resetting the down event (see comment above).

[tdresser, 2014/04/04 16:39:31]

Done.

+        Send(CreateGesture(ET_GESTURE_END, event));
+      break;
+    case MotionEvent::ACTION_POINTER_UP:
+      if (gesture_begin_end_types_enabled_)
+        Send(CreateGesture(ET_GESTURE_END, event));
+      break;
+    case MotionEvent::ACTION_DOWN:
+    case MotionEvent::ACTION_POINTER_DOWN:
+    case MotionEvent::ACTION_MOVE:
+      break;
+  }
+}
+
 }  //  namespace ui