Bug 1679645 - Cache the selection state in nsTextFrame rather than in nsDisplayText r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D108646

layout/generic/nsTextFrame.cpp

@@ -4899,12 +4899,10 @@ void nsTextFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
   bool isTextTransparent =
       NS_GET_A(st->mWebkitTextFillColor.CalcColor(this)) == 0 &&
       NS_GET_A(st->mWebkitTextStrokeColor.CalcColor(this)) == 0;
-  Maybe<bool> isSelected;
   if ((HasAnyStateBits(TEXT_NO_RENDERED_GLYPHS) ||
        (isTextTransparent && !StyleText()->HasTextShadow())) &&
       aBuilder->IsForPainting() && !SVGUtils::IsInSVGTextSubtree(this)) {
-    isSelected.emplace(IsSelected());
-    if (!isSelected.value()) {
+    if (!IsSelected()) {
       TextDecorations textDecs;
       GetTextDecorations(PresContext(), eResolvedColors, textDecs);
       if (!textDecs.HasDecorationLines()) {
@@ -4916,7 +4914,7 @@ void nsTextFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
     }
   }
 
-  aLists.Content()->AppendNewToTop<nsDisplayText>(aBuilder, this, isSelected);
+  aLists.Content()->AppendNewToTop<nsDisplayText>(aBuilder, this);
 }
 
 UniquePtr<SelectionDetails> nsTextFrame::GetSelectionDetails() {
@@ -7430,7 +7428,14 @@ bool nsTextFrame::CombineSelectionUnderlineRect(nsPresContext* aPresContext,
 bool nsTextFrame::IsFrameSelected() const {
   NS_ASSERTION(!GetContent() || GetContent()->IsMaybeSelected(),
                "use the public IsSelected() instead");
-  return GetContent()->IsSelected(GetContentOffset(), GetContentEnd());
+  if (mIsSelected == nsTextFrame::SelectionState::Unknown) {
+    const bool isSelected =
+        GetContent()->IsSelected(GetContentOffset(), GetContentEnd());
+    mIsSelected = isSelected ? nsTextFrame::SelectionState::Selected
+                             : nsTextFrame::SelectionState::NotSelected;
+  }
+
+  return mIsSelected == nsTextFrame::SelectionState::Selected;
 }
 
 void nsTextFrame::SelectionStateChanged(uint32_t aStart, uint32_t aEnd,
@@ -7440,6 +7445,8 @@ void nsTextFrame::SelectionStateChanged(uint32_t aStart, uint32_t aEnd,
                "Should only be called for primary frame");
   DEBUG_VERIFY_NOT_DIRTY(mState);
 
+  mIsSelected = nsTextFrame::SelectionState::Unknown;
+
   // Selection is collapsed, which can't affect text frame rendering
   if (aStart == aEnd) return;
 
@@ -9049,6 +9056,7 @@ void nsTextFrame::ReflowText(nsLineLayout& aLineLayout, nscoord aAvailableWidth,
                              DrawTarget* aDrawTarget, ReflowOutput& aMetrics,
                              nsReflowStatus& aStatus) {
   MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+  mIsSelected = nsTextFrame::SelectionState::Unknown;
 
 #ifdef NOISY_REFLOW
   ListTag(stdout);

layout/generic/nsTextFrame.h

@@ -202,7 +202,8 @@ class nsTextFrame : public nsIFrame {
         mNextContinuation(nullptr),
         mContentOffset(0),
         mContentLengthHint(0),
-        mAscent(0) {}
+        mAscent(0),
+        mIsSelected(SelectionState::Unknown) {}
 
   NS_DECL_FRAMEARENA_HELPERS(nsTextFrame)
 
@@ -802,6 +803,14 @@ class nsTextFrame : public nsIFrame {
   int32_t mContentLengthHint;
   nscoord mAscent;
 
+  // Cached selection state.
+  enum class SelectionState : uint8_t {
+    Unknown,
+    Selected,
+    NotSelected,
+  };
+  mutable SelectionState mIsSelected;
+
   /**
    * Return true if the frame is part of a Selection.
    * Helper method to implement the public IsSelected() API.

layout/painting/nsDisplayList.cpp

@@ -8752,25 +8752,24 @@ bool nsDisplayPerspective::ComputeVisibility(nsDisplayListBuilder* aBuilder,
 }
 
 nsDisplayText::nsDisplayText(nsDisplayListBuilder* aBuilder,
-                             nsTextFrame* aFrame,
-                             const Maybe<bool>& aIsSelected)
+                             nsTextFrame* aFrame)
     : nsPaintedDisplayItem(aBuilder, aFrame),
       mOpacity(1.0f),
       mVisIStartEdge(0),
       mVisIEndEdge(0) {
   MOZ_COUNT_CTOR(nsDisplayText);
-  mIsFrameSelected = aIsSelected;
   mBounds = mFrame->InkOverflowRectRelativeToSelf() + ToReferenceFrame();
   // Bug 748228
   mBounds.Inflate(mFrame->PresContext()->AppUnitsPerDevPixel());
 }
 
 bool nsDisplayText::CanApplyOpacity() const {
-  if (IsSelected()) {
+  auto* f = static_cast<nsTextFrame*>(mFrame);
+
+  if (f->IsSelected()) {
     return false;
   }
 
-  nsTextFrame* f = static_cast<nsTextFrame*>(mFrame);
   const nsStyleText* textStyle = f->StyleText();
   if (textStyle->HasTextShadow()) {
     return false;
@@ -8841,7 +8840,7 @@ bool nsDisplayText::CreateWebRenderCommands(
   // view. Also if we're selected we might have some shadows from the
   // ::selected and ::inctive-selected pseudo-selectors. So don't do this
   // optimization if we have shadows or a selection.
-  if (!(IsSelected() || f->StyleText()->HasTextShadow())) {
+  if (!(f->IsSelected() || f->StyleText()->HasTextShadow())) {
     nsRect visible = GetPaintRect();
     visible.Inflate(3 * appUnitsPerDevPixel);
     bounds = bounds.Intersect(visible);
@@ -8927,23 +8926,13 @@ void nsDisplayText::RenderToContext(gfxContext* aCtx,
   }
 
   f->PaintText(params, mVisIStartEdge, mVisIEndEdge, ToReferenceFrame(),
-               IsSelected(), mOpacity);
+               f->IsSelected(), mOpacity);
 
   if (willClip) {
     aCtx->PopClip();
   }
 }
 
-bool nsDisplayText::IsSelected() const {
-  if (mIsFrameSelected.isNothing()) {
-    MOZ_ASSERT((nsTextFrame*)do_QueryFrame(mFrame));
-    auto* f = static_cast<nsTextFrame*>(mFrame);
-    mIsFrameSelected.emplace(f->IsSelected());
-  }
-
-  return mIsFrameSelected.value();
-}
-
 class nsDisplayTextGeometry : public nsDisplayItemGenericGeometry {
  public:
   nsDisplayTextGeometry(nsDisplayText* aItem, nsDisplayListBuilder* aBuilder)

layout/painting/nsDisplayList.h

@@ -7119,19 +7119,16 @@ class nsDisplayPerspective : public nsPaintedDisplayItem {
  */
 class nsDisplayText final : public nsPaintedDisplayItem {
  public:
-  nsDisplayText(nsDisplayListBuilder* aBuilder, nsTextFrame* aFrame,
-                const mozilla::Maybe<bool>& aIsSelected);
+  nsDisplayText(nsDisplayListBuilder* aBuilder, nsTextFrame* aFrame);
   MOZ_COUNTED_DTOR_OVERRIDE(nsDisplayText)
 
   NS_DISPLAY_DECL_NAME("Text", TYPE_TEXT)
 
   bool RestoreState() final {
-    if (!nsPaintedDisplayItem::RestoreState() && mIsFrameSelected.isNothing() &&
-        mOpacity == 1.0f) {
+    if (!nsPaintedDisplayItem::RestoreState() && mOpacity == 1.0f) {
       return false;
     }
 
-    mIsFrameSelected.reset();
     mOpacity = 1.0f;
     return true;
   }
@@ -7195,8 +7192,6 @@ class nsDisplayText final : public nsPaintedDisplayItem {
                : nullptr;
   }
 
-  bool IsSelected() const;
-
   struct ClipEdges {
     ClipEdges(const nsIFrame* aFrame, const nsPoint& aToReferenceFrame,
               nscoord aVisIStartEdge, nscoord aVisIEndEdge) {
@@ -7237,9 +7232,6 @@ class nsDisplayText final : public nsPaintedDisplayItem {
   // regardless of bidi directionality; top and bottom in vertical modes).
   nscoord mVisIStartEdge;
   nscoord mVisIEndEdge;
-
-  // Cached result of mFrame->IsSelected().  Only initialized when needed.
-  mutable mozilla::Maybe<bool> mIsFrameSelected;
 };
 
 /**