tor-browser

nsInlineFrame.cpp (41739B)

---

/* -*- 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/. */

/* rendering object for CSS display:inline objects */

#include "nsInlineFrame.h"

#include "gfxContext.h"
#include "mozilla/ComputedStyle.h"
#include "mozilla/Likely.h"
#include "mozilla/PresShell.h"
#include "mozilla/RestyleManager.h"
#include "mozilla/SVGTextFrame.h"
#include "mozilla/ServoStyleSet.h"
#include "nsBlockFrame.h"
#include "nsCSSAnonBoxes.h"
#include "nsDisplayList.h"
#include "nsGkAtoms.h"
#include "nsLayoutUtils.h"
#include "nsLineLayout.h"
#include "nsPlaceholderFrame.h"
#include "nsPresContext.h"
#include "nsPresContextInlines.h"
#include "nsStyleChangeList.h"

#ifdef DEBUG
#  undef NOISY_PUSHING
#endif

using namespace mozilla;
using namespace mozilla::layout;

//////////////////////////////////////////////////////////////////////

// Basic nsInlineFrame methods

nsInlineFrame* NS_NewInlineFrame(PresShell* aPresShell, ComputedStyle* aStyle) {
 return new (aPresShell) nsInlineFrame(aStyle, aPresShell->GetPresContext());
}

NS_IMPL_FRAMEARENA_HELPERS(nsInlineFrame)

NS_QUERYFRAME_HEAD(nsInlineFrame)
 NS_QUERYFRAME_ENTRY(nsInlineFrame)
NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)

#ifdef DEBUG_FRAME_DUMP
nsresult nsInlineFrame::GetFrameName(nsAString& aResult) const {
 return MakeFrameName(u"Inline"_ns, aResult);
}
#endif

void nsInlineFrame::InvalidateFrame(uint32_t aDisplayItemKey,
                                   bool aRebuildDisplayItems) {
 if (IsInSVGTextSubtree()) {
   nsIFrame* svgTextFrame = nsLayoutUtils::GetClosestFrameOfType(
       GetParent(), LayoutFrameType::SVGText);
   svgTextFrame->InvalidateFrame();
   return;
 }
 nsContainerFrame::InvalidateFrame(aDisplayItemKey, aRebuildDisplayItems);
}

void nsInlineFrame::InvalidateFrameWithRect(const nsRect& aRect,
                                           uint32_t aDisplayItemKey,
                                           bool aRebuildDisplayItems) {
 if (IsInSVGTextSubtree()) {
   nsIFrame* svgTextFrame = nsLayoutUtils::GetClosestFrameOfType(
       GetParent(), LayoutFrameType::SVGText);
   svgTextFrame->InvalidateFrame();
   return;
 }
 nsContainerFrame::InvalidateFrameWithRect(aRect, aDisplayItemKey,
                                           aRebuildDisplayItems);
}

/* virtual */
bool nsInlineFrame::IsSelfEmpty() {
#if 0
 // I used to think inline frames worked this way, but it seems they
 // don't.  At least not in our codebase.
 if (GetPresContext()->CompatibilityMode() == eCompatibility_FullStandards) {
   return false;
 }
#endif
 const nsStyleMargin* margin = StyleMargin();
 const nsStyleBorder* border = StyleBorder();
 const nsStylePadding* padding = StylePadding();
 const auto anchorResolutionParams = AnchorPosResolutionParams::From(this);
 // Block-start and -end ignored, since they shouldn't affect things, but this
 // doesn't really match with nsLineLayout.cpp's setting of
 // ZeroEffectiveSpanBox, anymore, so what should this really be?
 WritingMode wm = GetWritingMode();
 bool haveStart, haveEnd;

 const auto IsMarginZero = [](const nsStyleMargin& aStyleMargin,
                              mozilla::Side aSide,
                              const AnchorPosResolutionParams& aParams) {
   const auto margin = aStyleMargin.GetMargin(aSide, aParams);
   if (!margin->IsLengthPercentage()) {
     return true;
   }
   const auto& lp = margin->AsLengthPercentage();
   return lp.Resolve(nscoord_MAX) == 0 && lp.Resolve(0) == 0;
 };

 auto HaveSide = [&](mozilla::Side aSide) -> bool {
   return border->GetComputedBorderWidth(aSide) != 0 ||
          !nsLayoutUtils::IsPaddingZero(padding->mPadding.Get(aSide)) ||
          !IsMarginZero(*margin, aSide, anchorResolutionParams);
 };
 // Initially set up haveStart and haveEnd in terms of visual (LTR/TTB)
 // coordinates; we'll exchange them later if bidi-RTL is in effect to
 // get logical start and end flags.
 if (wm.IsVertical()) {
   haveStart = HaveSide(eSideTop);
   haveEnd = HaveSide(eSideBottom);
 } else {
   haveStart = HaveSide(eSideLeft);
   haveEnd = HaveSide(eSideRight);
 }
 if (haveStart || haveEnd) {
   // We skip this block and return false for box-decoration-break:clone since
   // in that case all the continuations will have the border/padding/margin.
   if (HasAnyStateBits(NS_FRAME_PART_OF_IBSPLIT) &&
       StyleBorder()->mBoxDecorationBreak == StyleBoxDecorationBreak::Slice) {
     // When direction=rtl, we need to consider logical rather than visual
     // start and end, so swap the flags.
     if (wm.IsBidiRTL()) {
       std::swap(haveStart, haveEnd);
     }
     // For ib-split frames, ignore things we know we'll skip in GetSkipSides.
     // XXXbz should we be doing this for non-ib-split frames too, in a more
     // general way?

     // Get the first continuation eagerly, as a performance optimization, to
     // avoid having to get it twice..
     nsIFrame* firstCont = FirstContinuation();
     return (!haveStart || firstCont->FrameIsNonFirstInIBSplit()) &&
            (!haveEnd || firstCont->FrameIsNonLastInIBSplit());
   }
   return false;
 }
 return true;
}

bool nsInlineFrame::IsEmpty() {
 if (!IsSelfEmpty()) {
   return false;
 }

 for (nsIFrame* kid : mFrames) {
   if (!kid->IsEmpty()) {
     return false;
   }
 }

 return true;
}

nscoord nsInlineFrame::GetCaretBaseline() const {
 if (mBaseline == 0 && mRect.IsEmpty()) {
   nsBlockFrame* container = do_QueryFrame(FindLineContainer());
   // TODO(emilio): Ideally we'd want to find out if only our line is empty,
   // but that's non-trivial to do, and realistically empty inlines and text
   // will get placed into a non-empty line unless all lines are empty, I
   // believe...
   if (container && container->LinesAreEmpty()) {
     nscoord blockSize = container->ContentBSize(GetWritingMode());
     return GetFontMetricsDerivedCaretBaseline(blockSize);
   }
 }
 return nsIFrame::GetCaretBaseline();
}

nsIFrame::FrameSearchResult nsInlineFrame::PeekOffsetCharacter(
   bool aForward, int32_t* aOffset, PeekOffsetCharacterOptions aOptions) {
 // Override the implementation in nsFrame, to skip empty inline frames
 NS_ASSERTION(aOffset && *aOffset <= 1, "aOffset out of range");
 int32_t startOffset = *aOffset;
 if (startOffset < 0) {
   startOffset = 1;
 }
 if (aForward == (startOffset == 0)) {
   // We're before the frame and moving forward, or after it and moving
   // backwards: skip to the other side, but keep going.
   *aOffset = 1 - startOffset;
 }
 return CONTINUE;
}

void nsInlineFrame::Destroy(DestroyContext& aContext) {
 nsFrameList* overflowFrames = GetOverflowFrames();
 if (overflowFrames) {
   // Fixup the parent pointers for any child frames on the OverflowList.
   // nsIFrame::DestroyFrom depends on that to find the sticky scroll
   // container (an ancestor).
   overflowFrames->ApplySetParent(this);
 }
 nsContainerFrame::Destroy(aContext);
}

void nsInlineFrame::StealFrame(nsIFrame* aChild) {
 if (MaybeStealOverflowContainerFrame(aChild)) {
   return;
 }

 nsInlineFrame* parent = this;
 do {
   if (parent->mFrames.StartRemoveFrame(aChild)) {
     return;
   }

   // We didn't find the child in our principal child list.
   // Maybe it's on the overflow list?
   nsFrameList* frameList = parent->GetOverflowFrames();
   if (frameList && frameList->ContinueRemoveFrame(aChild)) {
     if (frameList->IsEmpty()) {
       parent->DestroyOverflowList();
     }
     return;
   }

   // Due to our "lazy reparenting" optimization 'aChild' might not actually
   // be on any of our child lists, but instead in one of our next-in-flows.
   parent = static_cast<nsInlineFrame*>(parent->GetNextInFlow());
 } while (parent);

 MOZ_ASSERT_UNREACHABLE("nsInlineFrame::StealFrame: can't find aChild");
}

void nsInlineFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
                                    const nsDisplayListSet& aLists) {
 BuildDisplayListForInline(aBuilder, aLists);

 // The sole purpose of this is to trigger display of the selection
 // window for Named Anchors, which don't have any children and
 // normally don't have any size, but in Editor we use CSS to display
 // an image to represent this "hidden" element.
 if (!mFrames.FirstChild()) {
   DisplaySelectionOverlay(aBuilder, aLists.Content());
 }
}

//////////////////////////////////////////////////////////////////////
// Reflow methods

/* virtual */
void nsInlineFrame::AddInlineMinISize(const IntrinsicSizeInput& aInput,
                                     InlineMinISizeData* aData) {
 DoInlineMinISize(aInput, aData);
}

/* virtual */
void nsInlineFrame::AddInlinePrefISize(const IntrinsicSizeInput& aInput,
                                      InlinePrefISizeData* aData) {
 DoInlinePrefISize(aInput, aData);
}

/* virtual */
nsIFrame::SizeComputationResult nsInlineFrame::ComputeSize(
   const SizeComputationInput& aSizingInput, WritingMode aWM,
   const LogicalSize& aCBSize, nscoord aAvailableISize,
   const LogicalSize& aMargin, const LogicalSize& aBorderPadding,
   const StyleSizeOverrides& aSizeOverrides, ComputeSizeFlags aFlags) {
 // Inlines and text don't compute size before reflow.
 return {LogicalSize(aWM, NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE),
         AspectRatioUsage::None};
}

nsRect nsInlineFrame::ComputeTightBounds(DrawTarget* aDrawTarget) const {
 // be conservative
 if (Style()->HasTextDecorationLines()) {
   return InkOverflowRect();
 }
 return ComputeSimpleTightBounds(aDrawTarget);
}

static void ReparentChildListStyle(nsPresContext* aPresContext,
                                  const nsFrameList::Slice& aFrames,
                                  nsIFrame* aParentFrame) {
 RestyleManager* restyleManager = aPresContext->RestyleManager();

 for (nsIFrame* f : aFrames) {
   NS_ASSERTION(f->GetParent() == aParentFrame, "Bogus parentage");
   restyleManager->ReparentComputedStyleForFirstLine(f);
   nsLayoutUtils::MarkDescendantsDirty(f);
 }
}

void nsInlineFrame::Reflow(nsPresContext* aPresContext,
                          ReflowOutput& aReflowOutput,
                          const ReflowInput& aReflowInput,
                          nsReflowStatus& aStatus) {
 MarkInReflow();
 DO_GLOBAL_REFLOW_COUNT("nsInlineFrame");
 MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");

 if (!aReflowInput.mLineLayout) {
   NS_ERROR("must have non-null aReflowInput.mLineLayout");
   return;
 }
 if (IsFrameTreeTooDeep(aReflowInput, aReflowOutput, aStatus)) {
   return;
 }

 bool lazilySetParentPointer = false;

 // Check for an overflow list with our prev-in-flow
 nsInlineFrame* prevInFlow = (nsInlineFrame*)GetPrevInFlow();
 if (prevInFlow) {
   AutoFrameListPtr prevOverflowFrames(aPresContext,
                                       prevInFlow->StealOverflowFrames());
   if (prevOverflowFrames) {
     // Check if we should do the lazilySetParentPointer optimization.
     // Only do it in simple cases where we're being reflowed for the
     // first time, nothing (e.g. bidi resolution) has already given
     // us children, and there's no next-in-flow, so all our frames
     // will be taken from prevOverflowFrames.
     if (HasAnyStateBits(NS_FRAME_FIRST_REFLOW) && mFrames.IsEmpty() &&
         !GetNextInFlow()) {
       // If our child list is empty, just put the new frames into it.
       // Note that we don't set the parent pointer for the new frames. Instead
       // wait to do this until we actually reflow the frame. If the overflow
       // list contains thousands of frames this is a big performance issue
       // (see bug #5588)
       mFrames = std::move(*prevOverflowFrames);
       lazilySetParentPointer = true;
     } else {
       // Insert the new frames at the beginning of the child list
       // and set their parent pointer
       const nsFrameList::Slice& newFrames =
           mFrames.InsertFrames(this, nullptr, std::move(*prevOverflowFrames));
       // If our prev in flow was under the first continuation of a first-line
       // frame then we need to reparent the ComputedStyles to remove the
       // the special first-line styling. In the lazilySetParentPointer case
       // we reparent the ComputedStyles when we set their parents in
       // nsInlineFrame::ReflowFrames and nsInlineFrame::ReflowInlineFrame.
       if (aReflowInput.mLineLayout->GetInFirstLine()) {
         ReparentChildListStyle(aPresContext, newFrames, this);
       }
     }
   }
 }

 // It's also possible that we have an overflow list for ourselves
#ifdef DEBUG
 if (HasAnyStateBits(NS_FRAME_FIRST_REFLOW)) {
   // If it's our initial reflow, then we should not have an overflow list.
   // However, add an assertion in case we get reflowed more than once with
   // the initial reflow reason
   nsFrameList* overflowFrames = GetOverflowFrames();
   NS_ASSERTION(!overflowFrames || overflowFrames->IsEmpty(),
                "overflow list is not empty for initial reflow");
 }
#endif
 if (!HasAnyStateBits(NS_FRAME_FIRST_REFLOW)) {
   DrainSelfOverflowListInternal(aReflowInput.mLineLayout->GetInFirstLine());
 }

 // Set our own reflow input (additional state above and beyond aReflowInput).
 InlineReflowInput irs;
 irs.mPrevFrame = nullptr;
 irs.mLineContainer = aReflowInput.mLineLayout->LineContainerFrame();
 irs.mLineLayout = aReflowInput.mLineLayout;
 irs.mNextInFlow = (nsInlineFrame*)GetNextInFlow();
 irs.mSetParentPointer = lazilySetParentPointer;

 if (mFrames.IsEmpty()) {
   // Try to pull over one frame before starting so that we know
   // whether we have an anonymous block or not.
   (void)PullOneFrame(aPresContext, irs);
 }

 ReflowFrames(aPresContext, aReflowInput, irs, aReflowOutput, aStatus);

 ReflowAbsoluteFrames(aPresContext, aReflowOutput, aReflowInput, aStatus);

 // Note: the line layout code will properly compute our
 // overflow-rect state for us.
}

nsresult nsInlineFrame::AttributeChanged(int32_t aNameSpaceID,
                                        nsAtom* aAttribute,
                                        AttrModType aModType) {
 nsresult rv =
     nsContainerFrame::AttributeChanged(aNameSpaceID, aAttribute, aModType);

 if (NS_FAILED(rv)) {
   return rv;
 }

 if (IsInSVGTextSubtree()) {
   SVGTextFrame* f = static_cast<SVGTextFrame*>(
       nsLayoutUtils::GetClosestFrameOfType(this, LayoutFrameType::SVGText));
   f->HandleAttributeChangeInDescendant(mContent->AsElement(), aNameSpaceID,
                                        aAttribute);
 }

 return NS_OK;
}

bool nsInlineFrame::DrainSelfOverflowListInternal(bool aInFirstLine) {
 AutoFrameListPtr overflowFrames(PresContext(), StealOverflowFrames());
 if (!overflowFrames || overflowFrames->IsEmpty()) {
   return false;
 }

 // The frames on our own overflowlist may have been pushed by a
 // previous lazilySetParentPointer Reflow so we need to ensure the
 // correct parent pointer.  This is sometimes skipped by Reflow.
 nsIFrame* firstChild = overflowFrames->FirstChild();
 RestyleManager* restyleManager = PresContext()->RestyleManager();
 for (nsIFrame* f = firstChild; f; f = f->GetNextSibling()) {
   f->SetParent(this);
   if (MOZ_UNLIKELY(aInFirstLine)) {
     restyleManager->ReparentComputedStyleForFirstLine(f);
     nsLayoutUtils::MarkDescendantsDirty(f);
   }
 }
 mFrames.AppendFrames(nullptr, std::move(*overflowFrames));
 return true;
}

/* virtual */
bool nsInlineFrame::DrainSelfOverflowList() {
 nsIFrame* lineContainer = nsLayoutUtils::FindNearestBlockAncestor(this);
 // Add the eInFirstLine flag if we have a ::first-line ancestor frame.
 // No need to look further than the nearest line container though.
 bool inFirstLine = false;
 for (nsIFrame* p = GetParent(); p != lineContainer; p = p->GetParent()) {
   if (p->IsLineFrame()) {
     inFirstLine = true;
     break;
   }
 }
 return DrainSelfOverflowListInternal(inFirstLine);
}

/* virtual */
bool nsInlineFrame::CanContinueTextRun() const {
 // We can continue a text run through an inline frame
 return true;
}

/* virtual */
void nsInlineFrame::PullOverflowsFromPrevInFlow() {
 nsInlineFrame* prevInFlow = static_cast<nsInlineFrame*>(GetPrevInFlow());
 if (prevInFlow) {
   nsPresContext* presContext = PresContext();
   AutoFrameListPtr prevOverflowFrames(presContext,
                                       prevInFlow->StealOverflowFrames());
   if (prevOverflowFrames) {
     mFrames.InsertFrames(this, nullptr, std::move(*prevOverflowFrames));
   }
 }
}

void nsInlineFrame::ReflowFrames(nsPresContext* aPresContext,
                                const ReflowInput& aReflowInput,
                                InlineReflowInput& irs,
                                ReflowOutput& aReflowOutput,
                                nsReflowStatus& aStatus) {
 MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");

 nsLineLayout* lineLayout = aReflowInput.mLineLayout;
 bool inFirstLine = aReflowInput.mLineLayout->GetInFirstLine();
 RestyleManager* restyleManager = aPresContext->RestyleManager();
 WritingMode frameWM = aReflowInput.GetWritingMode();
 WritingMode lineWM = aReflowInput.mLineLayout->GetWritingMode();
 LogicalMargin framePadding =
     aReflowInput.ComputedLogicalBorderPadding(frameWM);
 nscoord startEdge = 0;
 const bool boxDecorationBreakClone = MOZ_UNLIKELY(
     StyleBorder()->mBoxDecorationBreak == StyleBoxDecorationBreak::Clone);
 // Don't offset by our start borderpadding if we have a prev continuation or
 // if we're in a part of an {ib} split other than the first one. For
 // box-decoration-break:clone we always offset our start since all
 // continuations have border/padding.
 if ((!GetPrevContinuation() && !FrameIsNonFirstInIBSplit()) ||
     boxDecorationBreakClone) {
   startEdge = framePadding.IStart(frameWM);
 }
 nscoord availableISize = aReflowInput.AvailableISize();
 NS_ASSERTION(availableISize != NS_UNCONSTRAINEDSIZE,
              "should no longer use available widths");
 // Subtract off inline axis border+padding from availableISize
 availableISize -= startEdge;
 availableISize -= framePadding.IEnd(frameWM);
 lineLayout->BeginSpan(this, &aReflowInput, startEdge,
                       startEdge + availableISize, &mBaseline);

 // First reflow our principal children.
 nsIFrame* frame = mFrames.FirstChild();
 bool done = false;
 while (frame) {
   // Check if we should lazily set the child frame's parent pointer.
   if (irs.mSetParentPointer) {
     nsIFrame* child = frame;
     do {
       child->SetParent(this);
       if (inFirstLine) {
         restyleManager->ReparentComputedStyleForFirstLine(child);
         nsLayoutUtils::MarkDescendantsDirty(child);
       }
       // We also need to do the same for |frame|'s next-in-flows that are in
       // the sibling list. Otherwise, if we reflow |frame| and it's complete
       // we'll crash when trying to delete its next-in-flow.
       // This scenario doesn't happen often, but it can happen.
       nsIFrame* nextSibling = child->GetNextSibling();
       child = child->GetNextInFlow();
       if (MOZ_UNLIKELY(child)) {
         while (child != nextSibling && nextSibling) {
           nextSibling = nextSibling->GetNextSibling();
         }
         if (!nextSibling) {
           child = nullptr;
         }
       }
       MOZ_ASSERT(!child || mFrames.ContainsFrame(child));
     } while (child);

     // Fix the parent pointer for ::first-letter child frame next-in-flows,
     // so nsFirstLetterFrame::Reflow can destroy them safely (bug 401042).
     nsIFrame* realFrame = nsPlaceholderFrame::GetRealFrameFor(frame);
     if (realFrame->IsLetterFrame()) {
       nsIFrame* child = realFrame->PrincipalChildList().FirstChild();
       if (child) {
         NS_ASSERTION(child->IsTextFrame(), "unexpected frame type");
         nsIFrame* nextInFlow = child->GetNextInFlow();
         for (; nextInFlow; nextInFlow = nextInFlow->GetNextInFlow()) {
           NS_ASSERTION(nextInFlow->IsTextFrame(), "unexpected frame type");
           if (mFrames.ContainsFrame(nextInFlow)) {
             nextInFlow->SetParent(this);
             if (inFirstLine) {
               restyleManager->ReparentComputedStyleForFirstLine(nextInFlow);
               nsLayoutUtils::MarkDescendantsDirty(nextInFlow);
             }
           } else {
#ifdef DEBUG
             // Once we find a next-in-flow that isn't ours none of the
             // remaining next-in-flows should be either.
             for (; nextInFlow; nextInFlow = nextInFlow->GetNextInFlow()) {
               NS_ASSERTION(!mFrames.ContainsFrame(nextInFlow),
                            "unexpected letter frame flow");
             }
#endif
             break;
           }
         }
       }
     }
   }
   MOZ_ASSERT(frame->GetParent() == this);

   if (!done) {
     bool reflowingFirstLetter = lineLayout->GetFirstLetterStyleOK();
     ReflowInlineFrame(aPresContext, aReflowInput, irs, frame, aStatus);
     done = aStatus.IsInlineBreak() ||
            (!reflowingFirstLetter && aStatus.IsIncomplete());
     if (done) {
       if (!irs.mSetParentPointer) {
         break;
       }
       // Keep reparenting the remaining siblings, but don't reflow them.
       nsFrameList* pushedFrames = GetOverflowFrames();
       if (pushedFrames && pushedFrames->FirstChild() == frame) {
         // Don't bother if |frame| was pushed to our overflow list.
         break;
       }
     } else {
       irs.mPrevFrame = frame;
     }
   }
   frame = frame->GetNextSibling();
 }

 // Attempt to pull frames from our next-in-flow until we can't
 if (!done && GetNextInFlow()) {
   while (true) {
     bool reflowingFirstLetter = lineLayout->GetFirstLetterStyleOK();
     if (!frame) {  // Could be non-null if we pulled a first-letter frame and
                    // it created a continuation, since we don't push those.
       frame = PullOneFrame(aPresContext, irs);
     }
#ifdef NOISY_PUSHING
     printf("%p pulled up %p\n", this, frame);
#endif
     if (!frame) {
       break;
     }
     ReflowInlineFrame(aPresContext, aReflowInput, irs, frame, aStatus);
     if (aStatus.IsInlineBreak() ||
         (!reflowingFirstLetter && aStatus.IsIncomplete())) {
       break;
     }
     irs.mPrevFrame = frame;
     frame = frame->GetNextSibling();
   }
 }

 NS_ASSERTION(!aStatus.IsComplete() || !GetOverflowFrames(),
              "We can't be complete AND have overflow frames!");

 // If after reflowing our children they take up no area then make
 // sure that we don't either.
 //
 // Note: CSS demands that empty inline elements still affect the
 // line-height calculations. However, continuations of an inline
 // that are empty we force to empty so that things like collapsed
 // whitespace in an inline element don't affect the line-height.
 aReflowOutput.ISize(lineWM) = lineLayout->EndSpan(this);

 // Compute final width.

 // XXX Note that that the padding start and end are in the frame's
 //     writing mode, but the metrics' inline-size is in the line's
 //     writing mode. This makes sense if the line and frame are both
 //     vertical or both horizontal, but what should happen with
 //     orthogonal inlines?

 // Make sure to not include our start border and padding if we have a prev
 // continuation or if we're in a part of an {ib} split other than the first
 // one.  For box-decoration-break:clone we always include our start border
 // and padding since all continuations have them.
 if ((!GetPrevContinuation() && !FrameIsNonFirstInIBSplit()) ||
     boxDecorationBreakClone) {
   aReflowOutput.ISize(lineWM) += framePadding.IStart(frameWM);
 }

 /*
  * We want to only apply the end border and padding if we're the last
  * continuation and either not in an {ib} split or the last part of it.  To
  * be the last continuation we have to be complete (so that we won't get a
  * next-in-flow) and have no non-fluid continuations on our continuation
  * chain.  For box-decoration-break:clone we always apply the end border and
  * padding since all continuations have them.
  */
 if ((aStatus.IsComplete() && !LastInFlow()->GetNextContinuation() &&
      !FrameIsNonLastInIBSplit()) ||
     boxDecorationBreakClone) {
   aReflowOutput.ISize(lineWM) += framePadding.IEnd(frameWM);
 }

 nsLayoutUtils::SetBSizeFromFontMetrics(this, aReflowOutput, framePadding,
                                        lineWM, frameWM);

 // For now our overflow area is zero. The real value will be
 // computed in |nsLineLayout::RelativePositionFrames|.
 aReflowOutput.mOverflowAreas.Clear();

#ifdef NOISY_FINAL_SIZE
 ListTag(stdout);
 printf(": metrics=%d,%d ascent=%d\n", aReflowOutput.Width(),
        aReflowOutput.Height(), aReflowOutput.BlockStartAscent());
#endif
}

// Returns whether there's any remaining frame to pull.
/* static */
bool nsInlineFrame::HasFramesToPull(nsInlineFrame* aNextInFlow) {
 while (aNextInFlow) {
   if (!aNextInFlow->mFrames.IsEmpty()) {
     return true;
   }
   if (const nsFrameList* overflow = aNextInFlow->GetOverflowFrames()) {
     if (!overflow->IsEmpty()) {
       return true;
     }
   }
   aNextInFlow = static_cast<nsInlineFrame*>(aNextInFlow->GetNextInFlow());
 }
 return false;
}

void nsInlineFrame::ReflowInlineFrame(nsPresContext* aPresContext,
                                     const ReflowInput& aReflowInput,
                                     InlineReflowInput& irs, nsIFrame* aFrame,
                                     nsReflowStatus& aStatus) {
 nsLineLayout* lineLayout = aReflowInput.mLineLayout;
 bool reflowingFirstLetter = lineLayout->GetFirstLetterStyleOK();
 bool pushedFrame;
 aStatus.Reset();
 lineLayout->ReflowFrame(aFrame, aStatus, nullptr, pushedFrame);

 if (aStatus.IsInlineBreakBefore()) {
   if (aFrame != mFrames.FirstChild()) {
     // Change break-before status into break-after since we have
     // already placed at least one child frame. This preserves the
     // break-type so that it can be propagated upward.
     UsedClear oldClearType = aStatus.FloatClearType();
     aStatus.Reset();
     aStatus.SetIncomplete();
     aStatus.SetInlineLineBreakAfter(oldClearType);
     PushFrames(aPresContext, aFrame, irs.mPrevFrame, irs);
   } else {
     // Preserve reflow status when breaking-before our first child
     // and propagate it upward without modification.
   }
   return;
 }

 // Create a next-in-flow if needed.
 if (!aStatus.IsFullyComplete()) {
   CreateNextInFlow(aFrame);
 }

 if (aStatus.IsInlineBreakAfter()) {
   nsIFrame* nextFrame = aFrame->GetNextSibling();
   if (nextFrame) {
     aStatus.SetIncomplete();
     PushFrames(aPresContext, nextFrame, aFrame, irs);
   } else {
     // We must return an incomplete status if there are more child
     // frames remaining in a next-in-flow that follows this frame.
     if (HasFramesToPull(static_cast<nsInlineFrame*>(GetNextInFlow()))) {
       aStatus.SetIncomplete();
     }
   }
   return;
 }

 if (!aStatus.IsFullyComplete() && !reflowingFirstLetter) {
   nsIFrame* nextFrame = aFrame->GetNextSibling();
   if (nextFrame) {
     PushFrames(aPresContext, nextFrame, aFrame, irs);
   }
 }
}

nsIFrame* nsInlineFrame::PullOneFrame(nsPresContext* aPresContext,
                                     InlineReflowInput& irs) {
 nsIFrame* frame = nullptr;
 nsInlineFrame* nextInFlow = irs.mNextInFlow;

#ifdef DEBUG
 bool willPull = HasFramesToPull(nextInFlow);
#endif

 while (nextInFlow) {
   frame = nextInFlow->mFrames.FirstChild();
   if (!frame) {
     // The nextInFlow's principal list has no frames, try its overflow list.
     nsFrameList* overflowFrames = nextInFlow->GetOverflowFrames();
     if (overflowFrames) {
       frame = overflowFrames->RemoveFirstChild();
       if (overflowFrames->IsEmpty()) {
         // We're stealing the only frame - delete the overflow list.
         nextInFlow->DestroyOverflowList();
       } else {
         // We leave the remaining frames on the overflow list (rather than
         // putting them on nextInFlow's principal list) so we don't have to
         // set up the parent for them.
       }
       // ReparentFloatsForInlineChild needs it to be on a child list -
       // we remove it again below.
       nextInFlow->mFrames = nsFrameList(frame, frame);
     }
   }

   if (frame) {
     // If our block has no next continuation, then any floats belonging to
     // the pulled frame must belong to our block already. This check ensures
     // we do no extra work in the common non-vertical-breaking case.
     if (irs.mLineContainer && irs.mLineContainer->GetNextContinuation()) {
       // The blockChildren.ContainsFrame check performed by
       // ReparentFloatsForInlineChild will be fast because frame's ancestor
       // will be the first child of its containing block.
       ReparentFloatsForInlineChild(irs.mLineContainer, frame, false);
     }
     nextInFlow->mFrames.RemoveFirstChild();
     // nsFirstLineFrame::PullOneFrame calls ReparentComputedStyle.

     mFrames.InsertFrame(this, irs.mPrevFrame, frame);
     if (irs.mLineLayout) {
       irs.mLineLayout->SetDirtyNextLine();
     }
     break;
   }
   nextInFlow = static_cast<nsInlineFrame*>(nextInFlow->GetNextInFlow());
   irs.mNextInFlow = nextInFlow;
 }

 MOZ_ASSERT(!!frame == willPull);
 return frame;
}

void nsInlineFrame::PushFrames(nsPresContext* aPresContext,
                              nsIFrame* aFromChild, nsIFrame* aPrevSibling,
                              InlineReflowInput& aState) {
#ifdef NOISY_PUSHING
 printf("%p pushing aFromChild %p, disconnecting from prev sib %p\n", this,
        aFromChild, aPrevSibling);
#endif

 PushChildrenToOverflow(aFromChild, aPrevSibling);
 if (aState.mLineLayout) {
   aState.mLineLayout->SetDirtyNextLine();
 }
}

//////////////////////////////////////////////////////////////////////

LogicalSides nsInlineFrame::GetLogicalSkipSides() const {
 LogicalSides skip(mWritingMode);
 if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                  StyleBoxDecorationBreak::Clone)) {
   return skip;
 }

 if (!IsFirst()) {
   nsInlineFrame* prev = (nsInlineFrame*)GetPrevContinuation();
   if (HasAnyStateBits(NS_INLINE_FRAME_BIDI_VISUAL_STATE_IS_SET) ||
       (prev && (prev->mRect.height || prev->mRect.width))) {
     // Prev continuation is not empty therefore we don't render our start
     // border edge.
     skip += LogicalSide::IStart;
   } else {
     // If the prev continuation is empty, then go ahead and let our start
     // edge border render.
   }
 }
 if (!IsLast()) {
   nsInlineFrame* next = (nsInlineFrame*)GetNextContinuation();
   if (HasAnyStateBits(NS_INLINE_FRAME_BIDI_VISUAL_STATE_IS_SET) ||
       (next && (next->mRect.height || next->mRect.width))) {
     // Next continuation is not empty therefore we don't render our end
     // border edge.
     skip += LogicalSide::IEnd;
   } else {
     // If the next continuation is empty, then go ahead and let our end
     // edge border render.
   }
 }

 if (HasAnyStateBits(NS_FRAME_PART_OF_IBSPLIT)) {
   // All but the last part of an {ib} split should skip the "end" side (as
   // determined by this frame's direction) and all but the first part of such
   // a split should skip the "start" side.  But figuring out which part of
   // the split we are involves getting our first continuation, which might be
   // expensive.  So don't bother if we already have the relevant bits set.
   if (skip != LogicalSides(mWritingMode, LogicalSides::IBoth)) {
     // We're missing one of the skip bits, so check whether we need to set it.
     // Only get the first continuation once, as an optimization.
     nsIFrame* firstContinuation = FirstContinuation();
     if (firstContinuation->FrameIsNonLastInIBSplit()) {
       skip += LogicalSide::IEnd;
     }
     if (firstContinuation->FrameIsNonFirstInIBSplit()) {
       skip += LogicalSide::IStart;
     }
   }
 }

 return skip;
}

Maybe<nscoord> nsInlineFrame::GetNaturalBaselineBOffset(
   WritingMode aWM, BaselineSharingGroup aBaselineGroup,
   BaselineExportContext) const {
 if (aBaselineGroup == BaselineSharingGroup::Last) {
   return Nothing{};
 }
 // TODO(dshin): Some functions seem to rely on this returning
 // NS_INTRINSIC_ISIZE_UNKNOWN. e.g. /css/css-pseudo/target-text-008.html
 return Some(mBaseline);
}

#ifdef ACCESSIBILITY
a11y::AccType nsInlineFrame::AccessibleType() {
 // FIXME(emilio): This is broken, if the image has its default `display` value
 // overridden. Should be somewhere else.
 if (mContent->IsHTMLElement(
         nsGkAtoms::img)) {  // Create accessible for broken <img>
   return a11y::eHyperTextType;
 }

 return a11y::eNoType;
}
#endif

void nsInlineFrame::UpdateStyleOfOwnedAnonBoxesForIBSplit(
   ServoRestyleState& aRestyleState) {
 MOZ_ASSERT(HasAnyStateBits(NS_FRAME_OWNS_ANON_BOXES),
            "Why did we get called?");
 MOZ_ASSERT(HasAnyStateBits(NS_FRAME_PART_OF_IBSPLIT),
            "Why did we have the NS_FRAME_OWNS_ANON_BOXES bit set?");
 // Note: this assert _looks_ expensive, but it's cheap in all the cases when
 // it passes!
 MOZ_ASSERT(nsLayoutUtils::FirstContinuationOrIBSplitSibling(this) == this,
            "Only the primary frame of the inline in a block-inside-inline "
            "split should have NS_FRAME_OWNS_ANON_BOXES");
 MOZ_ASSERT(mContent->GetPrimaryFrame() == this,
            "We should be the primary frame for our element");

 nsIFrame* blockFrame = GetProperty(nsIFrame::IBSplitSibling());
 MOZ_ASSERT(blockFrame, "Why did we have an IB split?");

 // The later inlines need to get our style.
 ComputedStyle* ourStyle = Style();

 // The anonymous block's style inherits from ours, and we already have our new
 // ComputedStyle.
 RefPtr<ComputedStyle> newContext =
     aRestyleState.StyleSet().ResolveInheritingAnonymousBoxStyle(
         PseudoStyleType::mozBlockInsideInlineWrapper, ourStyle);

 // We're guaranteed that newContext only differs from the old ComputedStyle on
 // the block in things they might inherit from us.  And changehint processing
 // guarantees walking the continuation and ib-sibling chains, so our existing
 // changehint being in aChangeList is good enough.  So we don't need to touch
 // aChangeList at all here.

 while (blockFrame) {
   MOZ_ASSERT(!blockFrame->GetPrevContinuation(),
              "Must be first continuation");

   MOZ_ASSERT(blockFrame->Style()->GetPseudoType() ==
                  PseudoStyleType::mozBlockInsideInlineWrapper,
              "Unexpected kind of ComputedStyle");

   for (nsIFrame* cont = blockFrame; cont;
        cont = cont->GetNextContinuation()) {
     cont->SetComputedStyle(newContext);
   }

   nsIFrame* nextInline = blockFrame->GetProperty(nsIFrame::IBSplitSibling());
   MOZ_ASSERT(nextInline, "There is always a trailing inline in an IB split");

   for (nsIFrame* cont = nextInline; cont;
        cont = cont->GetNextContinuation()) {
     cont->SetComputedStyle(ourStyle);
   }
   blockFrame = nextInline->GetProperty(nsIFrame::IBSplitSibling());
 }
}

//////////////////////////////////////////////////////////////////////

// nsLineFrame implementation

nsFirstLineFrame* NS_NewFirstLineFrame(PresShell* aPresShell,
                                      ComputedStyle* aStyle) {
 return new (aPresShell)
     nsFirstLineFrame(aStyle, aPresShell->GetPresContext());
}

NS_IMPL_FRAMEARENA_HELPERS(nsFirstLineFrame)

void nsFirstLineFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
                           nsIFrame* aPrevInFlow) {
 nsInlineFrame::Init(aContent, aParent, aPrevInFlow);
 if (!aPrevInFlow) {
   MOZ_ASSERT(Style()->GetPseudoType() == PseudoStyleType::firstLine);
   return;
 }

 // This frame is a continuation - fixup the computed style if aPrevInFlow
 // is the first-in-flow (the only one with a ::first-line pseudo).
 if (aPrevInFlow->Style()->GetPseudoType() == PseudoStyleType::firstLine) {
   MOZ_ASSERT(FirstInFlow() == aPrevInFlow);
   // Create a new ComputedStyle that is a child of the parent
   // ComputedStyle thus removing the ::first-line style. This way
   // we behave as if an anonymous (unstyled) span was the child
   // of the parent frame.
   ComputedStyle* parentContext = aParent->Style();
   RefPtr<ComputedStyle> newSC =
       PresContext()->StyleSet()->ResolveInheritingAnonymousBoxStyle(
           PseudoStyleType::mozLineFrame, parentContext);
   SetComputedStyle(newSC);
 } else {
   MOZ_ASSERT(FirstInFlow() != aPrevInFlow);
   MOZ_ASSERT(aPrevInFlow->Style()->GetPseudoType() ==
              PseudoStyleType::mozLineFrame);
 }
}

#ifdef DEBUG_FRAME_DUMP
nsresult nsFirstLineFrame::GetFrameName(nsAString& aResult) const {
 return MakeFrameName(u"Line"_ns, aResult);
}
#endif

nsIFrame* nsFirstLineFrame::PullOneFrame(nsPresContext* aPresContext,
                                        InlineReflowInput& irs) {
 nsIFrame* frame = nsInlineFrame::PullOneFrame(aPresContext, irs);
 if (frame && !GetPrevInFlow()) {
   // We are a first-line frame. Fixup the child frames
   // style-context that we just pulled.
   NS_ASSERTION(frame->GetParent() == this, "Incorrect parent?");
   aPresContext->RestyleManager()->ReparentComputedStyleForFirstLine(frame);
   nsLayoutUtils::MarkDescendantsDirty(frame);
 }
 return frame;
}

void nsFirstLineFrame::Reflow(nsPresContext* aPresContext,
                             ReflowOutput& aReflowOutput,
                             const ReflowInput& aReflowInput,
                             nsReflowStatus& aStatus) {
 MarkInReflow();
 MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");

 if (nullptr == aReflowInput.mLineLayout) {
   return;  // XXX does this happen? why?
 }

 // Check for an overflow list with our prev-in-flow
 nsFirstLineFrame* prevInFlow = (nsFirstLineFrame*)GetPrevInFlow();
 if (prevInFlow) {
   AutoFrameListPtr prevOverflowFrames(aPresContext,
                                       prevInFlow->StealOverflowFrames());
   if (prevOverflowFrames) {
     // Reparent the new frames and their ComputedStyles.
     const nsFrameList::Slice& newFrames =
         mFrames.InsertFrames(this, nullptr, std::move(*prevOverflowFrames));
     ReparentChildListStyle(aPresContext, newFrames, this);
   }
 }

 // It's also possible that we have an overflow list for ourselves.
 DrainSelfOverflowList();

 // Set our own reflow input (additional state above and beyond aReflowInput).
 InlineReflowInput irs;
 irs.mPrevFrame = nullptr;
 irs.mLineContainer = aReflowInput.mLineLayout->LineContainerFrame();
 irs.mLineLayout = aReflowInput.mLineLayout;
 irs.mNextInFlow = (nsInlineFrame*)GetNextInFlow();

 bool wasEmpty = mFrames.IsEmpty();
 if (wasEmpty) {
   // Try to pull over one frame before starting so that we know
   // whether we have an anonymous block or not.
   PullOneFrame(aPresContext, irs);
 }

 if (nullptr == GetPrevInFlow()) {
   // XXX This is pretty sick, but what we do here is to pull-up, in
   // advance, all of the next-in-flows children. We re-resolve their
   // style while we are at at it so that when we reflow they have
   // the right style.
   //
   // All of this is so that text-runs reflow properly.
   irs.mPrevFrame = mFrames.LastChild();
   for (;;) {
     nsIFrame* frame = PullOneFrame(aPresContext, irs);
     if (!frame) {
       break;
     }
     irs.mPrevFrame = frame;
   }
   irs.mPrevFrame = nullptr;
 }

 NS_ASSERTION(!aReflowInput.mLineLayout->GetInFirstLine(),
              "Nested first-line frames? BOGUS");
 aReflowInput.mLineLayout->SetInFirstLine(true);
 ReflowFrames(aPresContext, aReflowInput, irs, aReflowOutput, aStatus);
 aReflowInput.mLineLayout->SetInFirstLine(false);

 ReflowAbsoluteFrames(aPresContext, aReflowOutput, aReflowInput, aStatus);

 // Note: the line layout code will properly compute our overflow state for us
}

/* virtual */
void nsFirstLineFrame::PullOverflowsFromPrevInFlow() {
 nsFirstLineFrame* prevInFlow =
     static_cast<nsFirstLineFrame*>(GetPrevInFlow());
 if (prevInFlow) {
   nsPresContext* presContext = PresContext();
   AutoFrameListPtr prevOverflowFrames(presContext,
                                       prevInFlow->StealOverflowFrames());
   if (prevOverflowFrames) {
     // Assume that our prev-in-flow has the same line container that we do.
     const nsFrameList::Slice& newFrames =
         mFrames.InsertFrames(this, nullptr, std::move(*prevOverflowFrames));
     ReparentChildListStyle(presContext, newFrames, this);
   }
 }
}

/* virtual */
bool nsFirstLineFrame::DrainSelfOverflowList() {
 AutoFrameListPtr overflowFrames(PresContext(), StealOverflowFrames());
 if (overflowFrames) {
   bool result = !overflowFrames->IsEmpty();
   const nsFrameList::Slice& newFrames =
       mFrames.AppendFrames(nullptr, std::move(*overflowFrames));
   ReparentChildListStyle(PresContext(), newFrames, this);
   return result;
 }
 return false;
}