1 files changed, 132 insertions, 0 deletions
diff --git a/dom/ipc/CoalescedTouchData.cpp b/dom/ipc/CoalescedTouchData.cpp
new file mode 100644
index 0000000000..3c3bc71a0c
--- /dev/null
+++ b/dom/ipc/CoalescedTouchData.cpp
@@ -0,0 +1,132 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CoalescedTouchData.h"
+#include "BrowserChild.h"
+#include "mozilla/dom/PointerEventHandler.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+static const uint32_t sMaxTouchMoveIdentifiers = 10;
+
+void CoalescedTouchData::CreateCoalescedTouchEvent(
+    const WidgetTouchEvent& aEvent) {
+  MOZ_ASSERT(IsEmpty());
+  mCoalescedInputEvent = MakeUnique<WidgetTouchEvent>(aEvent);
+  for (size_t i = 0; i < mCoalescedInputEvent->mTouches.Length(); i++) {
+    const RefPtr<Touch>& touch = mCoalescedInputEvent->mTouches[i];
+    touch->mCoalescedWidgetEvents = MakeAndAddRef<WidgetPointerEventHolder>();
+    // Add an initial event into coalesced events, so
+    // the relevant pointer event would at least contain one coalesced event.
+    WidgetPointerEvent* event =
+        touch->mCoalescedWidgetEvents->mEvents.AppendElement(WidgetPointerEvent(
+            aEvent.IsTrusted(), ePointerMove, aEvent.mWidget));
+    PointerEventHandler::InitPointerEventFromTouch(*event, aEvent, *touch,
+                                                   i == 0);
+    event->mFlags.mBubbles = false;
+    event->mFlags.mCancelable = false;
+  }
+}
+
+void CoalescedTouchData::Coalesce(const WidgetTouchEvent& aEvent,
+                                  const ScrollableLayerGuid& aGuid,
+                                  const uint64_t& aInputBlockId,
+                                  const nsEventStatus& aApzResponse) {
+  MOZ_ASSERT(aEvent.mMessage == eTouchMove);
+  if (IsEmpty()) {
+    CreateCoalescedTouchEvent(aEvent);
+    mGuid = aGuid;
+    mInputBlockId = aInputBlockId;
+    mApzResponse = aApzResponse;
+  } else {
+    MOZ_ASSERT(mGuid == aGuid);
+    MOZ_ASSERT(mInputBlockId == aInputBlockId);
+    MOZ_ASSERT(mCoalescedInputEvent->mModifiers == aEvent.mModifiers);
+    MOZ_ASSERT(mCoalescedInputEvent->mInputSource == aEvent.mInputSource);
+
+    for (size_t i = 0; i < aEvent.mTouches.Length(); i++) {
+      const RefPtr<Touch>& touch = aEvent.mTouches[i];
+      // Get the same touch in the original event
+      RefPtr<Touch> sameTouch = GetTouch(touch->Identifier());
+      // The checks in CoalescedTouchData::CanCoalesce ensure it should never
+      // be null.
+      MOZ_ASSERT(sameTouch);
+      MOZ_ASSERT(sameTouch->mCoalescedWidgetEvents);
+      MOZ_ASSERT(!sameTouch->mCoalescedWidgetEvents->mEvents.IsEmpty());
+      if (!sameTouch->Equals(touch)) {
+        sameTouch->SetSameAs(touch);
+        WidgetPointerEvent* event =
+            sameTouch->mCoalescedWidgetEvents->mEvents.AppendElement(
+                WidgetPointerEvent(aEvent.IsTrusted(), ePointerMove,
+                                   aEvent.mWidget));
+        PointerEventHandler::InitPointerEventFromTouch(*event, aEvent, *touch,
+                                                       i == 0);
+        event->mFlags.mBubbles = false;
+        event->mFlags.mCancelable = false;
+      }
+    }
+
+    mCoalescedInputEvent->mTimeStamp = aEvent.mTimeStamp;
+  }
+}
+
+bool CoalescedTouchData::CanCoalesce(const WidgetTouchEvent& aEvent,
+                                     const ScrollableLayerGuid& aGuid,
+                                     const uint64_t& aInputBlockId,
+                                     const nsEventStatus& aApzResponse) {
+  MOZ_ASSERT(!IsEmpty());
+  if (mGuid != aGuid || mInputBlockId != aInputBlockId ||
+      mCoalescedInputEvent->mModifiers != aEvent.mModifiers ||
+      mCoalescedInputEvent->mInputSource != aEvent.mInputSource ||
+      aEvent.mTouches.Length() > sMaxTouchMoveIdentifiers) {
+    return false;
+  }
+
+  // Ensures both touchmove events have the same touches
+  if (aEvent.mTouches.Length() != mCoalescedInputEvent->mTouches.Length()) {
+    return false;
+  }
+  for (const RefPtr<Touch>& touch : aEvent.mTouches) {
+    if (!GetTouch(touch->Identifier())) {
+      return false;
+    }
+  }
+
+  // If one of them is eIgnore and the other one is eConsumeDoDefault,
+  // we always coalesce them to eConsumeDoDefault.
+  if (mApzResponse != aApzResponse) {
+    if (mApzResponse == nsEventStatus::nsEventStatus_eIgnore &&
+        aApzResponse == nsEventStatus::nsEventStatus_eConsumeDoDefault) {
+      mApzResponse = aApzResponse;
+    } else if (mApzResponse != nsEventStatus::nsEventStatus_eConsumeDoDefault ||
+               aApzResponse != nsEventStatus::nsEventStatus_eIgnore) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+Touch* CoalescedTouchData::GetTouch(int32_t aIdentifier) {
+  for (const RefPtr<Touch>& touch : mCoalescedInputEvent->mTouches) {
+    if (touch->Identifier() == aIdentifier) {
+      return touch;
+    }
+  }
+  return nullptr;
+}
+
+void CoalescedTouchMoveFlusher::WillRefresh(mozilla::TimeStamp aTime) {
+  MOZ_ASSERT(mRefreshDriver);
+  mBrowserChild->ProcessPendingCoalescedTouchData();
+}
+
+CoalescedTouchMoveFlusher::CoalescedTouchMoveFlusher(
+    BrowserChild* aBrowserChild)
+    : CoalescedInputFlusher(aBrowserChild) {}
+
+CoalescedTouchMoveFlusher::~CoalescedTouchMoveFlusher() { RemoveObserver(); }