tor-browser

The Tor Browser
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HitTestInfo.cpp (2273B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #include "HitTestInfo.h"
      8 
      9 #include "mozilla/StaticPtr.h"
     10 #include "mozilla/layers/ScrollableLayerGuid.h"
     11 #include "mozilla/webrender/WebRenderAPI.h"
     12 #include "nsDisplayList.h"
     13 #include "nsIFrame.h"
     14 
     15 using namespace mozilla::gfx;
     16 
     17 namespace mozilla {
     18 
     19 static StaticAutoPtr<const HitTestInfo> gEmptyHitTestInfo;
     20 
     21 const HitTestInfo& HitTestInfo::Empty() {
     22  if (!gEmptyHitTestInfo) {
     23    gEmptyHitTestInfo = new HitTestInfo();
     24  }
     25 
     26  return *gEmptyHitTestInfo;
     27 }
     28 
     29 void HitTestInfo::Shutdown() { gEmptyHitTestInfo = nullptr; }
     30 
     31 using ViewID = layers::ScrollableLayerGuid::ViewID;
     32 
     33 ViewID HitTestInfo::GetViewId(wr::DisplayListBuilder& aBuilder,
     34                              const ActiveScrolledRoot* aASR) const {
     35  if (mScrollTarget) {
     36    return *mScrollTarget;
     37  }
     38 
     39  Maybe<ViewID> fixedTarget = aBuilder.GetContainingFixedPosScrollTarget(aASR);
     40 
     41  if (fixedTarget) {
     42    return *fixedTarget;
     43  }
     44 
     45  // If the input ASR is non-null and we have a parent scroll ASR, return the
     46  // view id from that ASR.
     47  if (aASR) {
     48    return aASR->GetNearestScrollASRViewId();
     49  }
     50 
     51  return layers::ScrollableLayerGuid::NULL_SCROLL_ID;
     52 }
     53 
     54 void HitTestInfo::Initialize(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame) {
     55  if (!aBuilder->BuildCompositorHitTestInfo()) {
     56    return;
     57  }
     58 
     59  mInfo = aFrame->GetCompositorHitTestInfo(aBuilder);
     60  if (mInfo != gfx::CompositorHitTestInvisibleToHit) {
     61    mArea = aFrame->GetCompositorHitTestArea(aBuilder);
     62    InitializeScrollTarget(aBuilder);
     63  }
     64 }
     65 
     66 void HitTestInfo::InitializeScrollTarget(nsDisplayListBuilder* aBuilder) {
     67  if (aBuilder->GetCurrentScrollbarDirection().isSome()) {
     68    // In the case of scrollbar frames, we use the scrollbar's target
     69    // scrollframe instead of the scrollframe with which the scrollbar actually
     70    // moves.
     71    MOZ_ASSERT(Info().contains(CompositorHitTestFlags::eScrollbar));
     72    mScrollTarget = Some(aBuilder->GetCurrentScrollbarTarget());
     73  }
     74 }
     75 
     76 }  // namespace mozilla