Implement compositor thread VSync aligned event queue

content/common/input/event_with_latency_info.cc

 // Copyright 2016 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 "content/common/input/event_with_latency_info.h"
 
-#include <bitset>
-#include <limits>
-
-using blink::WebGestureEvent;
 using blink::WebInputEvent;
-using blink::WebKeyboardEvent;
-using blink::WebMouseEvent;
-using blink::WebMouseWheelEvent;
-using blink::WebTouchEvent;
-using std::numeric_limits;
 
 namespace content {
-namespace {
-
-const int kInvalidTouchIndex = -1;
-
-float GetUnacceleratedDelta(float accelerated_delta, float acceleration_ratio) {
-  return accelerated_delta * acceleration_ratio;
-}
-
-float GetAccelerationRatio(float accelerated_delta, float unaccelerated_delta) {
-  if (unaccelerated_delta == 0.f || accelerated_delta == 0.f)
-    return 1.f;
-  return unaccelerated_delta / accelerated_delta;
-}
-
-// Returns |kInvalidTouchIndex| iff |event| lacks a touch with an ID of |id|.
-int GetIndexOfTouchID(const WebTouchEvent& event, int id) {
-  for (unsigned i = 0; i < event.touchesLength; ++i) {
-    if (event.touches[i].id == id)
-      return i;
-  }
-  return kInvalidTouchIndex;
-}
-
-WebInputEvent::DispatchType MergeDispatchTypes(
-    WebInputEvent::DispatchType type_1,
-    WebInputEvent::DispatchType type_2) {
-  static_assert(WebInputEvent::DispatchType::Blocking <
-                    WebInputEvent::DispatchType::EventNonBlocking,
-                "Enum not ordered correctly");
-  static_assert(WebInputEvent::DispatchType::EventNonBlocking <
-                    WebInputEvent::DispatchType::ListenersNonBlockingPassive,
-                "Enum not ordered correctly");
-  static_assert(
-      WebInputEvent::DispatchType::ListenersNonBlockingPassive <
-          WebInputEvent::DispatchType::ListenersForcedNonBlockingDueToFling,
-      "Enum not ordered correctly");
-  return static_cast<WebInputEvent::DispatchType>(
-      std::min(static_cast<int>(type_1), static_cast<int>(type_2)));
-}
-
-}  // namespace
-
-namespace internal {
-
-bool CanCoalesce(const WebMouseEvent& event_to_coalesce,
-                 const WebMouseEvent& event) {
-  return event.type == event_to_coalesce.type &&
-         event.type == WebInputEvent::MouseMove;
-}
-
-void Coalesce(const WebMouseEvent& event_to_coalesce, WebMouseEvent* event) {
-  DCHECK(CanCoalesce(event_to_coalesce, *event));
-  // Accumulate movement deltas.
-  int x = event->movementX;
-  int y = event->movementY;
-  *event = event_to_coalesce;
-  event->movementX += x;
-  event->movementY += y;
-}
-
-bool CanCoalesce(const WebMouseWheelEvent& event_to_coalesce,
-                 const WebMouseWheelEvent& event) {
-  return event.modifiers == event_to_coalesce.modifiers &&
-         event.scrollByPage == event_to_coalesce.scrollByPage &&
-         event.phase == event_to_coalesce.phase &&
-         event.momentumPhase == event_to_coalesce.momentumPhase &&
-         event.hasPreciseScrollingDeltas ==
-             event_to_coalesce.hasPreciseScrollingDeltas;
-}
-
-void Coalesce(const WebMouseWheelEvent& event_to_coalesce,
-              WebMouseWheelEvent* event) {
-  DCHECK(CanCoalesce(event_to_coalesce, *event));
-  float unaccelerated_x =
-      GetUnacceleratedDelta(event->deltaX, event->accelerationRatioX) +
-      GetUnacceleratedDelta(event_to_coalesce.deltaX,
-                            event_to_coalesce.accelerationRatioX);
-  float unaccelerated_y =
-      GetUnacceleratedDelta(event->deltaY, event->accelerationRatioY) +
-      GetUnacceleratedDelta(event_to_coalesce.deltaY,
-                            event_to_coalesce.accelerationRatioY);
-  float old_deltaX = event->deltaX;
-  float old_deltaY = event->deltaY;
-  float old_wheelTicksX = event->wheelTicksX;
-  float old_wheelTicksY = event->wheelTicksY;
-  float old_movementX = event->movementX;
-  float old_movementY = event->movementY;
-  *event = event_to_coalesce;
-  event->deltaX += old_deltaX;
-  event->deltaY += old_deltaY;
-  event->wheelTicksX += old_wheelTicksX;
-  event->wheelTicksY += old_wheelTicksY;
-  event->movementX += old_movementX;
-  event->movementY += old_movementY;
-  event->accelerationRatioX =
-      GetAccelerationRatio(event->deltaX, unaccelerated_x);
-  event->accelerationRatioY =
-      GetAccelerationRatio(event->deltaY, unaccelerated_y);
-}
-
-bool CanCoalesce(const WebTouchEvent& event_to_coalesce,
-                 const WebTouchEvent& event) {
-  if (event.type != event_to_coalesce.type ||
-      event.type != WebInputEvent::TouchMove ||
-      event.modifiers != event_to_coalesce.modifiers ||
-      event.touchesLength != event_to_coalesce.touchesLength ||
-      event.touchesLength > WebTouchEvent::kTouchesLengthCap)
-    return false;
-
-  static_assert(WebTouchEvent::kTouchesLengthCap <= sizeof(int32_t) * 8U,
-                "suboptimal kTouchesLengthCap size");
-  // Ensure that we have a 1-to-1 mapping of pointer ids between touches.
-  std::bitset<WebTouchEvent::kTouchesLengthCap> unmatched_event_touches(
-      (1 << event.touchesLength) - 1);
-  for (unsigned i = 0; i < event_to_coalesce.touchesLength; ++i) {
-    int event_touch_index =
-        GetIndexOfTouchID(event, event_to_coalesce.touches[i].id);
-    if (event_touch_index == kInvalidTouchIndex)
-      return false;
-    if (!unmatched_event_touches[event_touch_index])
-      return false;
-    unmatched_event_touches[event_touch_index] = false;
-  }
-  return unmatched_event_touches.none();
-}
-
-void Coalesce(const WebTouchEvent& event_to_coalesce, WebTouchEvent* event) {
-  DCHECK(CanCoalesce(event_to_coalesce, *event));
-  // The WebTouchPoints include absolute position information. So it is
-  // sufficient to simply replace the previous event with the new event->
-  // However, it is necessary to make sure that all the points have the
-  // correct state, i.e. the touch-points that moved in the last event, but
-  // didn't change in the current event, will have Stationary state. It is
-  // necessary to change them back to Moved state.
-  WebTouchEvent old_event = *event;
-  *event = event_to_coalesce;
-  for (unsigned i = 0; i < event->touchesLength; ++i) {
-    int i_old = GetIndexOfTouchID(old_event, event->touches[i].id);
-    if (old_event.touches[i_old].state == blink::WebTouchPoint::StateMoved)
-      event->touches[i].state = blink::WebTouchPoint::StateMoved;
-  }
-  event->movedBeyondSlopRegion |= old_event.movedBeyondSlopRegion;
-  event->dispatchType = MergeDispatchTypes(old_event.dispatchType,
-                                           event_to_coalesce.dispatchType);
-}
-
-bool CanCoalesce(const WebGestureEvent& event_to_coalesce,
-                 const WebGestureEvent& event) {
-  if (event.type != event_to_coalesce.type ||
-      event.sourceDevice != event_to_coalesce.sourceDevice ||
-      event.modifiers != event_to_coalesce.modifiers)
-    return false;
-
-  if (event.type == WebInputEvent::GestureScrollUpdate)
-    return true;
-
-  // GesturePinchUpdate scales can be combined only if they share a focal point,
-  // e.g., with double-tap drag zoom.
-  if (event.type == WebInputEvent::GesturePinchUpdate &&
-      event.x == event_to_coalesce.x && event.y == event_to_coalesce.y)
-    return true;
-
-  return false;
-}
-
-void Coalesce(const WebGestureEvent& event_to_coalesce,
-              WebGestureEvent* event) {
-  DCHECK(CanCoalesce(event_to_coalesce, *event));
-  if (event->type == WebInputEvent::GestureScrollUpdate) {
-    event->data.scrollUpdate.deltaX +=
-        event_to_coalesce.data.scrollUpdate.deltaX;
-    event->data.scrollUpdate.deltaY +=
-        event_to_coalesce.data.scrollUpdate.deltaY;
-    DCHECK_EQ(
-        event->data.scrollUpdate.previousUpdateInSequencePrevented,
-        event_to_coalesce.data.scrollUpdate.previousUpdateInSequencePrevented);
-  } else if (event->type == WebInputEvent::GesturePinchUpdate) {
-    event->data.pinchUpdate.scale *= event_to_coalesce.data.pinchUpdate.scale;
-    // Ensure the scale remains bounded above 0 and below Infinity so that
-    // we can reliably perform operations like log on the values.
-    if (event->data.pinchUpdate.scale < numeric_limits<float>::min())
-      event->data.pinchUpdate.scale = numeric_limits<float>::min();
-    else if (event->data.pinchUpdate.scale > numeric_limits<float>::max())
-      event->data.pinchUpdate.scale = numeric_limits<float>::max();
-  }
-}
-
-bool CanCoalesce(const blink::WebInputEvent& event_to_coalesce,
-                 const blink::WebInputEvent& event) {
-  if (blink::WebInputEvent::isGestureEventType(event_to_coalesce.type) &&
-      blink::WebInputEvent::isGestureEventType(event.type)) {
-    return CanCoalesce(
-        static_cast<const blink::WebGestureEvent&>(event_to_coalesce),
-        static_cast<const blink::WebGestureEvent&>(event));
-  }
-  if (blink::WebInputEvent::isMouseEventType(event_to_coalesce.type) &&
-      blink::WebInputEvent::isMouseEventType(event.type)) {
-    return CanCoalesce(
-        static_cast<const blink::WebMouseEvent&>(event_to_coalesce),
-        static_cast<const blink::WebMouseEvent&>(event));
-  }
-  if (blink::WebInputEvent::isTouchEventType(event_to_coalesce.type) &&
-      blink::WebInputEvent::isTouchEventType(event.type)) {
-    return CanCoalesce(
-        static_cast<const blink::WebTouchEvent&>(event_to_coalesce),
-        static_cast<const blink::WebTouchEvent&>(event));
-  }
-  if (event_to_coalesce.type == blink::WebInputEvent::MouseWheel &&
-      event.type == blink::WebInputEvent::MouseWheel) {
-    return CanCoalesce(
-        static_cast<const blink::WebMouseWheelEvent&>(event_to_coalesce),
-        static_cast<const blink::WebMouseWheelEvent&>(event));
-  }
-  return false;
-}
-
-void Coalesce(const blink::WebInputEvent& event_to_coalesce,
-              blink::WebInputEvent* event) {
-  if (blink::WebInputEvent::isGestureEventType(event_to_coalesce.type) &&
-      blink::WebInputEvent::isGestureEventType(event->type)) {
-    Coalesce(static_cast<const blink::WebGestureEvent&>(event_to_coalesce),
-             static_cast<blink::WebGestureEvent*>(event));
-    return;
-  }
-  if (blink::WebInputEvent::isMouseEventType(event_to_coalesce.type) &&
-      blink::WebInputEvent::isMouseEventType(event->type)) {
-    Coalesce(static_cast<const blink::WebMouseEvent&>(event_to_coalesce),
-             static_cast<blink::WebMouseEvent*>(event));
-    return;
-  }
-  if (blink::WebInputEvent::isTouchEventType(event_to_coalesce.type) &&
-      blink::WebInputEvent::isTouchEventType(event->type)) {
-    Coalesce(static_cast<const blink::WebTouchEvent&>(event_to_coalesce),
-             static_cast<blink::WebTouchEvent*>(event));
-    return;
-  }
-  if (event_to_coalesce.type == blink::WebInputEvent::MouseWheel &&
-      event->type == blink::WebInputEvent::MouseWheel) {
-    Coalesce(static_cast<const blink::WebMouseWheelEvent&>(event_to_coalesce),
-             static_cast<blink::WebMouseWheelEvent*>(event));
-  }
-}
-
-}  // namespace internal
 
 ScopedWebInputEventWithLatencyInfo::ScopedWebInputEventWithLatencyInfo(
     ui::ScopedWebInputEvent event,
     const ui::LatencyInfo& latency_info)
     : event_(std::move(event)), latency_(latency_info) {
 }
 
 ScopedWebInputEventWithLatencyInfo::~ScopedWebInputEventWithLatencyInfo() {}
 
 bool ScopedWebInputEventWithLatencyInfo::CanCoalesceWith(
     const ScopedWebInputEventWithLatencyInfo& other) const {
-  return internal::CanCoalesce(other.event(), event());
+  return ui::CanCoalesce(other.event(), event());
 }
 
 void ScopedWebInputEventWithLatencyInfo::CoalesceWith(
     const ScopedWebInputEventWithLatencyInfo& other) {
   // |other| should be a newer event than |this|.
   if (other.latency_.trace_id() >= 0 && latency_.trace_id() >= 0)
     DCHECK_GT(other.latency_.trace_id(), latency_.trace_id());
 
   // New events get coalesced into older events, and the newer timestamp
   // should always be preserved.
   const double time_stamp_seconds = other.event().timeStampSeconds;
-  internal::Coalesce(other.event(), event_.get());
+  ui::Coalesce(other.event(), event_.get());
   event_->timeStampSeconds = time_stamp_seconds;
 
   // When coalescing two input events, we keep the oldest LatencyInfo
   // since it will represent the longest latency.
   other.latency_ = latency_;
   other.latency_.set_coalesced();
 }
 
 const blink::WebInputEvent& ScopedWebInputEventWithLatencyInfo::event() const {
   return *event_;
 }
 
 blink::WebInputEvent& ScopedWebInputEventWithLatencyInfo::event() {
   return *event_;
 }
 
 }  // namespace content