content/browser/renderer_host/input/gesture_event_queue.cc

   1 // Copyright 2014 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 #include "content/browser/renderer_host/input/gesture_event_queue.h"
   6
   7 #include "base/trace_event/trace_event.h"
   8 #include "content/browser/renderer_host/input/touchpad_tap_suppression_controller.h"
   9 #include "content/browser/renderer_host/input/touchscreen_tap_suppression_controller.h"
  10
  11 using blink::WebGestureEvent;
  12 using blink::WebInputEvent;
  13
  14 namespace content {
  15 namespace {
  16
  17 // Whether |event_in_queue| is GesturePinchUpdate or GestureScrollUpdate and
  18 // has the same modifiers/source as the new scroll/pinch event. Compatible
  19 // scroll and pinch event pairs can be logically coalesced.
  20 bool IsCompatibleScrollorPinch(
  21     const GestureEventWithLatencyInfo& new_event,
  22     const GestureEventWithLatencyInfo& event_in_queue) {
  23   DCHECK(new_event.event.type == WebInputEvent::GestureScrollUpdate ||
  24          new_event.event.type == WebInputEvent::GesturePinchUpdate)
  25       << "Invalid event type for pinch/scroll coalescing: "
  26       << WebInputEventTraits::GetName(new_event.event.type);
  27   DLOG_IF(WARNING, new_event.event.timeStampSeconds <
  28                        event_in_queue.event.timeStampSeconds)
  29       << "Event time not monotonic?\n";
  30   return (event_in_queue.event.type == WebInputEvent::GestureScrollUpdate ||
  31           event_in_queue.event.type == WebInputEvent::GesturePinchUpdate) &&
  32          event_in_queue.event.modifiers == new_event.event.modifiers &&
  33          event_in_queue.event.sourceDevice == new_event.event.sourceDevice;
  34 }
  35
  36 // Returns the transform matrix corresponding to the gesture event.
  37 gfx::Transform GetTransformForEvent(
  38     const GestureEventWithLatencyInfo& gesture_event) {
  39   gfx::Transform gesture_transform;
  40   if (gesture_event.event.type == WebInputEvent::GestureScrollUpdate) {
  41     gesture_transform.Translate(gesture_event.event.data.scrollUpdate.deltaX,
  42                                 gesture_event.event.data.scrollUpdate.deltaY);
  43   } else if (gesture_event.event.type == WebInputEvent::GesturePinchUpdate) {
  44     float scale = gesture_event.event.data.pinchUpdate.scale;
  45     gesture_transform.Translate(-gesture_event.event.x, -gesture_event.event.y);
  46     gesture_transform.Scale(scale, scale);
  47     gesture_transform.Translate(gesture_event.event.x, gesture_event.event.y);
  48   } else {
  49     NOTREACHED() << "Invalid event type for transform retrieval: "
  50                  << WebInputEventTraits::GetName(gesture_event.event.type);
  51   }
  52   return gesture_transform;
  53 }
  54
  55 }  // namespace
  56
  57 GestureEventQueue::Config::Config() {
  58 }
  59
  60 GestureEventQueue::GestureEventQueue(
  61     GestureEventQueueClient* client,
  62     TouchpadTapSuppressionControllerClient* touchpad_client,
  63     const Config& config)
  64     : client_(client),
  65       fling_in_progress_(false),
  66       scrolling_in_progress_(false),
  67       ignore_next_ack_(false),
  68       touchpad_tap_suppression_controller_(
  69           touchpad_client,
  70           config.touchpad_tap_suppression_config),
  71       touchscreen_tap_suppression_controller_(
  72           this,
  73           config.touchscreen_tap_suppression_config),
  74       debounce_interval_(config.debounce_interval) {
  75   DCHECK(client);
  76   DCHECK(touchpad_client);
  77 }
  78
  79 GestureEventQueue::~GestureEventQueue() { }
  80
  81 void GestureEventQueue::QueueEvent(
  82     const GestureEventWithLatencyInfo& gesture_event) {
  83   TRACE_EVENT0("input", "GestureEventQueue::QueueEvent");
  84   if (!ShouldForwardForBounceReduction(gesture_event) ||
  85       !ShouldForwardForGFCFiltering(gesture_event) ||
  86       !ShouldForwardForTapSuppression(gesture_event)) {
  87     return;
  88   }
  89
  90   QueueAndForwardIfNecessary(gesture_event);
  91 }
  92
  93 bool GestureEventQueue::ShouldDiscardFlingCancelEvent(
  94     const GestureEventWithLatencyInfo& gesture_event) const {
  95   if (coalesced_gesture_events_.empty() && fling_in_progress_)
  96     return false;
  97   GestureQueue::const_reverse_iterator it =
  98       coalesced_gesture_events_.rbegin();
  99   while (it != coalesced_gesture_events_.rend()) {
 100     if (it->event.type == WebInputEvent::GestureFlingStart)
 101       return false;
 102     if (it->event.type == WebInputEvent::GestureFlingCancel)
 103       return true;
 104     it++;
 105   }
 106   return true;
 107 }
 108
 109 bool GestureEventQueue::ShouldForwardForBounceReduction(
 110     const GestureEventWithLatencyInfo& gesture_event) {
 111   if (debounce_interval_ <= base::TimeDelta())
 112     return true;
 113   switch (gesture_event.event.type) {
 114     case WebInputEvent::GestureScrollUpdate:
 115       if (!scrolling_in_progress_) {
 116         debounce_deferring_timer_.Start(
 117             FROM_HERE,
 118             debounce_interval_,
 119             this,
 120             &GestureEventQueue::SendScrollEndingEventsNow);
 121       } else {
 122         // Extend the bounce interval.
 123         debounce_deferring_timer_.Reset();
 124       }
 125       scrolling_in_progress_ = true;
 126       debouncing_deferral_queue_.clear();
 127       return true;
 128     case WebInputEvent::GesturePinchBegin:
 129     case WebInputEvent::GesturePinchEnd:
 130     case WebInputEvent::GesturePinchUpdate:
 131       // TODO(rjkroege): Debounce pinch (http://crbug.com/147647)
 132       return true;
 133     default:
 134       if (scrolling_in_progress_) {
 135         debouncing_deferral_queue_.push_back(gesture_event);
 136         return false;
 137       }
 138       return true;
 139   }
 140 }
 141
 142 bool GestureEventQueue::ShouldForwardForGFCFiltering(
 143     const GestureEventWithLatencyInfo& gesture_event) const {
 144   return gesture_event.event.type != WebInputEvent::GestureFlingCancel ||
 145       !ShouldDiscardFlingCancelEvent(gesture_event);
 146 }
 147
 148 bool GestureEventQueue::ShouldForwardForTapSuppression(
 149     const GestureEventWithLatencyInfo& gesture_event) {
 150   switch (gesture_event.event.type) {
 151     case WebInputEvent::GestureFlingCancel:
 152       if (gesture_event.event.sourceDevice ==
 153           blink::WebGestureDeviceTouchscreen)
 154         touchscreen_tap_suppression_controller_.GestureFlingCancel();
 155       else
 156         touchpad_tap_suppression_controller_.GestureFlingCancel();
 157       return true;
 158     case WebInputEvent::GestureTapDown:
 159     case WebInputEvent::GestureShowPress:
 160     case WebInputEvent::GestureTapUnconfirmed:
 161     case WebInputEvent::GestureTapCancel:
 162     case WebInputEvent::GestureTap:
 163     case WebInputEvent::GestureDoubleTap:
 164       if (gesture_event.event.sourceDevice ==
 165           blink::WebGestureDeviceTouchscreen) {
 166         return !touchscreen_tap_suppression_controller_.FilterTapEvent(
 167             gesture_event);
 168       }
 169       return true;
 170     default:
 171       return true;
 172   }
 173 }
 174
 175 void GestureEventQueue::QueueAndForwardIfNecessary(
 176     const GestureEventWithLatencyInfo& gesture_event) {
 177   switch (gesture_event.event.type) {
 178     case WebInputEvent::GestureFlingCancel:
 179       fling_in_progress_ = false;
 180       break;
 181     case WebInputEvent::GestureFlingStart:
 182       fling_in_progress_ = true;
 183       break;
 184     case WebInputEvent::GesturePinchUpdate:
 185     case WebInputEvent::GestureScrollUpdate:
 186       QueueScrollOrPinchAndForwardIfNecessary(gesture_event);
 187       return;
 188     default:
 189       break;
 190   }
 191
 192   coalesced_gesture_events_.push_back(gesture_event);
 193   if (coalesced_gesture_events_.size() == 1)
 194     client_->SendGestureEventImmediately(gesture_event);
 195 }
 196
 197 void GestureEventQueue::ProcessGestureAck(InputEventAckState ack_result,
 198                                           WebInputEvent::Type type,
 199                                           const ui::LatencyInfo& latency) {
 200   TRACE_EVENT0("input", "GestureEventQueue::ProcessGestureAck");
 201
 202   if (coalesced_gesture_events_.empty()) {
 203     DLOG(ERROR) << "Received unexpected ACK for event type " << type;
 204     return;
 205   }
 206
 207   // It's possible that the ack for the second event in an in-flight, coalesced
 208   // Gesture{Scroll,Pinch}Update pair is received prior to the first event ack.
 209   // TODO(jdduke): Unify GSU/GPU pairs into a single event, crbug.com/359115.
 210   size_t event_index = 0;
 211   if (ignore_next_ack_ &&
 212       coalesced_gesture_events_.size() > 1 &&
 213       coalesced_gesture_events_[0].event.type != type &&
 214       coalesced_gesture_events_[1].event.type == type) {
 215     event_index = 1;
 216   }
 217   GestureEventWithLatencyInfo event_with_latency =
 218       coalesced_gesture_events_[event_index];
 219   DCHECK_EQ(event_with_latency.event.type, type);
 220   event_with_latency.latency.AddNewLatencyFrom(latency);
 221
 222   // Ack'ing an event may enqueue additional gesture events.  By ack'ing the
 223   // event before the forwarding of queued events below, such additional events
 224   // can be coalesced with existing queued events prior to dispatch.
 225   client_->OnGestureEventAck(event_with_latency, ack_result);
 226
 227   const bool processed = (INPUT_EVENT_ACK_STATE_CONSUMED == ack_result);
 228   if (type == WebInputEvent::GestureFlingCancel) {
 229     if (event_with_latency.event.sourceDevice ==
 230         blink::WebGestureDeviceTouchscreen)
 231       touchscreen_tap_suppression_controller_.GestureFlingCancelAck(processed);
 232     else
 233       touchpad_tap_suppression_controller_.GestureFlingCancelAck(processed);
 234   }
 235   DCHECK_LT(event_index, coalesced_gesture_events_.size());
 236   coalesced_gesture_events_.erase(coalesced_gesture_events_.begin() +
 237                                   event_index);
 238
 239   if (ignore_next_ack_) {
 240     ignore_next_ack_ = false;
 241     return;
 242   }
 243
 244   if (coalesced_gesture_events_.empty())
 245     return;
 246
 247   const GestureEventWithLatencyInfo& first_gesture_event =
 248       coalesced_gesture_events_.front();
 249
 250   // TODO(jdduke): Unify GSU/GPU pairs into a single event, crbug.com/359115.
 251   // Check for the coupled GesturePinchUpdate before sending either event,
 252   // handling the case where the first GestureScrollUpdate ack is synchronous.
 253   GestureEventWithLatencyInfo second_gesture_event;
 254   if (first_gesture_event.event.type == WebInputEvent::GestureScrollUpdate &&
 255       coalesced_gesture_events_.size() > 1 &&
 256       coalesced_gesture_events_[1].event.type ==
 257           WebInputEvent::GesturePinchUpdate) {
 258     second_gesture_event = coalesced_gesture_events_[1];
 259     ignore_next_ack_ = true;
 260   }
 261
 262   client_->SendGestureEventImmediately(first_gesture_event);
 263   if (second_gesture_event.event.type != WebInputEvent::Undefined)
 264     client_->SendGestureEventImmediately(second_gesture_event);
 265 }
 266
 267 TouchpadTapSuppressionController*
 268     GestureEventQueue::GetTouchpadTapSuppressionController() {
 269   return &touchpad_tap_suppression_controller_;
 270 }
 271
 272 void GestureEventQueue::FlingHasBeenHalted() {
 273   fling_in_progress_ = false;
 274 }
 275
 276 void GestureEventQueue::ForwardGestureEvent(
 277     const GestureEventWithLatencyInfo& gesture_event) {
 278   QueueAndForwardIfNecessary(gesture_event);
 279 }
 280
 281 void GestureEventQueue::SendScrollEndingEventsNow() {
 282   scrolling_in_progress_ = false;
 283   if (debouncing_deferral_queue_.empty())
 284     return;
 285   GestureQueue debouncing_deferral_queue;
 286   debouncing_deferral_queue.swap(debouncing_deferral_queue_);
 287   for (GestureQueue::const_iterator it = debouncing_deferral_queue.begin();
 288        it != debouncing_deferral_queue.end(); it++) {
 289     if (ShouldForwardForGFCFiltering(*it) &&
 290         ShouldForwardForTapSuppression(*it)) {
 291       QueueAndForwardIfNecessary(*it);
 292     }
 293   }
 294 }
 295
 296 void GestureEventQueue::QueueScrollOrPinchAndForwardIfNecessary(
 297     const GestureEventWithLatencyInfo& gesture_event) {
 298   DCHECK_GE(coalesced_gesture_events_.size(), EventsInFlightCount());
 299   const size_t unsent_events_count =
 300       coalesced_gesture_events_.size() - EventsInFlightCount();
 301   if (!unsent_events_count) {
 302     coalesced_gesture_events_.push_back(gesture_event);
 303     if (coalesced_gesture_events_.size() == 1) {
 304       client_->SendGestureEventImmediately(gesture_event);
 305     } else if (coalesced_gesture_events_.size() == 2) {
 306       DCHECK(!ignore_next_ack_);
 307       // If there is an in-flight scroll, the new pinch can be forwarded
 308       // immediately, avoiding a potential frame delay between the two
 309       // (similarly for an in-flight pinch with a new scroll).
 310       const GestureEventWithLatencyInfo& first_event =
 311           coalesced_gesture_events_.front();
 312       if (gesture_event.event.type != first_event.event.type &&
 313           IsCompatibleScrollorPinch(gesture_event, first_event)) {
 314         ignore_next_ack_ = true;
 315         client_->SendGestureEventImmediately(gesture_event);
 316       }
 317     }
 318     return;
 319   }
 320
 321   GestureEventWithLatencyInfo* last_event = &coalesced_gesture_events_.back();
 322   if (last_event->CanCoalesceWith(gesture_event)) {
 323     last_event->CoalesceWith(gesture_event);
 324     return;
 325   }
 326
 327   if (!IsCompatibleScrollorPinch(gesture_event, *last_event)) {
 328     coalesced_gesture_events_.push_back(gesture_event);
 329     return;
 330   }
 331
 332   GestureEventWithLatencyInfo scroll_event;
 333   GestureEventWithLatencyInfo pinch_event;
 334   scroll_event.event.modifiers |= gesture_event.event.modifiers;
 335   scroll_event.event.sourceDevice = gesture_event.event.sourceDevice;
 336   scroll_event.event.timeStampSeconds = gesture_event.event.timeStampSeconds;
 337   // Keep the oldest LatencyInfo.
 338   DCHECK_LE(last_event->latency.trace_id(), gesture_event.latency.trace_id());
 339   scroll_event.latency = last_event->latency;
 340   pinch_event = scroll_event;
 341   scroll_event.event.type = WebInputEvent::GestureScrollUpdate;
 342   pinch_event.event.type = WebInputEvent::GesturePinchUpdate;
 343   pinch_event.event.x = gesture_event.event.type ==
 344       WebInputEvent::GesturePinchUpdate ?
 345           gesture_event.event.x : last_event->event.x;
 346   pinch_event.event.y = gesture_event.event.type ==
 347       WebInputEvent::GesturePinchUpdate ?
 348           gesture_event.event.y : last_event->event.y;
 349
 350   gfx::Transform combined_scroll_pinch = GetTransformForEvent(*last_event);
 351   // Only include the second-to-last event in the coalesced pair if it exists
 352   // and can be combined with the new event.
 353   if (unsent_events_count > 1) {
 354     const GestureEventWithLatencyInfo& second_last_event =
 355         coalesced_gesture_events_[coalesced_gesture_events_.size() - 2];
 356     if (IsCompatibleScrollorPinch(gesture_event, second_last_event)) {
 357       // Keep the oldest LatencyInfo.
 358       DCHECK_LE(second_last_event.latency.trace_id(),
 359                 scroll_event.latency.trace_id());
 360       scroll_event.latency = second_last_event.latency;
 361       pinch_event.latency = second_last_event.latency;
 362       combined_scroll_pinch.PreconcatTransform(
 363           GetTransformForEvent(second_last_event));
 364       coalesced_gesture_events_.pop_back();
 365     }
 366   }
 367   combined_scroll_pinch.ConcatTransform(GetTransformForEvent(gesture_event));
 368   coalesced_gesture_events_.pop_back();
 369
 370   float combined_scale =
 371       SkMScalarToFloat(combined_scroll_pinch.matrix().get(0, 0));
 372   float combined_scroll_pinch_x =
 373       SkMScalarToFloat(combined_scroll_pinch.matrix().get(0, 3));
 374   float combined_scroll_pinch_y =
 375       SkMScalarToFloat(combined_scroll_pinch.matrix().get(1, 3));
 376   scroll_event.event.data.scrollUpdate.deltaX =
 377       (combined_scroll_pinch_x + pinch_event.event.x) / combined_scale -
 378       pinch_event.event.x;
 379   scroll_event.event.data.scrollUpdate.deltaY =
 380       (combined_scroll_pinch_y + pinch_event.event.y) / combined_scale -
 381       pinch_event.event.y;
 382   coalesced_gesture_events_.push_back(scroll_event);
 383   pinch_event.event.data.pinchUpdate.scale = combined_scale;
 384   coalesced_gesture_events_.push_back(pinch_event);
 385 }
 386
 387 size_t GestureEventQueue::EventsInFlightCount() const {
 388   if (coalesced_gesture_events_.empty())
 389     return 0;
 390
 391   if (!ignore_next_ack_)
 392     return 1;
 393
 394   DCHECK_GT(coalesced_gesture_events_.size(), 1U);
 395   return 2;
 396 }
 397
 398 }  // namespace content