author Iulian Moraru <>
Fri, 07 May 2021 22:40:08 +0300
changeset 578910 950445712e58889c9ed92c22d63e5ee0e6880fec
parent 572568 00afc841497293ea739793df69e7db1ddb577f57
permissions -rw-r--r--
Backed out changeset 7f3071ee22e0 (bug 1710046) for causing gecko decision failure. CLOSED TREE

/* -*- 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 */

/* rendering object for CSS :first-letter pseudo-element */

#include "nsFirstLetterFrame.h"
#include "nsPresContext.h"
#include "nsPresContextInlines.h"
#include "mozilla/ComputedStyle.h"
#include "mozilla/PresShell.h"
#include "mozilla/PresShellInlines.h"
#include "mozilla/RestyleManager.h"
#include "mozilla/ServoStyleSet.h"
#include "nsIContent.h"
#include "nsLayoutUtils.h"
#include "nsLineLayout.h"
#include "nsGkAtoms.h"
#include "nsFrameManager.h"
#include "nsPlaceholderFrame.h"
#include "nsCSSFrameConstructor.h"

using namespace mozilla;
using namespace mozilla::layout;

nsFirstLetterFrame* NS_NewFirstLetterFrame(PresShell* aPresShell,
                                           ComputedStyle* aStyle) {
  return new (aPresShell)
      nsFirstLetterFrame(aStyle, aPresShell->GetPresContext());



nsresult nsFirstLetterFrame::GetFrameName(nsAString& aResult) const {
  return MakeFrameName(u"Letter"_ns, aResult);

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

void nsFirstLetterFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
                              nsIFrame* aPrevInFlow) {
  RefPtr<ComputedStyle> newSC;
  if (aPrevInFlow) {
    // Get proper ComputedStyle for ourselves.  We're creating the frame
    // that represents everything *except* the first letter, so just create
    // a ComputedStyle that inherits from our style parent, with no extra rules.
    nsIFrame* styleParent =
        CorrectStyleParentFrame(aParent, PseudoStyleType::firstLetter);
    ComputedStyle* parentComputedStyle = styleParent->Style();
    newSC = PresContext()->StyleSet()->ResolveStyleForFirstLetterContinuation(

  nsContainerFrame::Init(aContent, aParent, aPrevInFlow);

void nsFirstLetterFrame::SetInitialChildList(ChildListID aListID,
                                             nsFrameList& aChildList) {
  MOZ_ASSERT(aListID == kPrincipalList,
             "Principal child list is the only "
             "list that nsFirstLetterFrame should set via this function");
  for (nsIFrame* f : aChildList) {
    MOZ_ASSERT(f->GetParent() == this, "Unexpected parent");
               "We should not have kids that are containers!");
    nsLayoutUtils::MarkDescendantsDirty(f);  // Drops cached textruns


nsresult nsFirstLetterFrame::GetChildFrameContainingOffset(
    int32_t inContentOffset, bool inHint, int32_t* outFrameContentOffset,
    nsIFrame** outChildFrame) {
  nsIFrame* kid = mFrames.FirstChild();
  if (kid) {
    return kid->GetChildFrameContainingOffset(
        inContentOffset, inHint, outFrameContentOffset, outChildFrame);
  return nsIFrame::GetChildFrameContainingOffset(
      inContentOffset, inHint, outFrameContentOffset, outChildFrame);

// Needed for non-floating first-letter frames and for the continuations
// following the first-letter that we also use nsFirstLetterFrame for.
/* virtual */
void nsFirstLetterFrame::AddInlineMinISize(
    gfxContext* aRenderingContext, nsIFrame::InlineMinISizeData* aData) {
  DoInlineMinISize(aRenderingContext, aData);

// Needed for non-floating first-letter frames and for the continuations
// following the first-letter that we also use nsFirstLetterFrame for.
/* virtual */
void nsFirstLetterFrame::AddInlinePrefISize(
    gfxContext* aRenderingContext, nsIFrame::InlinePrefISizeData* aData) {
  DoInlinePrefISize(aRenderingContext, aData);

// Needed for floating first-letter frames.
/* virtual */
nscoord nsFirstLetterFrame::GetMinISize(gfxContext* aRenderingContext) {
  return nsLayoutUtils::MinISizeFromInline(this, aRenderingContext);

// Needed for floating first-letter frames.
/* virtual */
nscoord nsFirstLetterFrame::GetPrefISize(gfxContext* aRenderingContext) {
  return nsLayoutUtils::PrefISizeFromInline(this, aRenderingContext);

/* virtual */
nsIFrame::SizeComputationResult nsFirstLetterFrame::ComputeSize(
    gfxContext* aRenderingContext, WritingMode aWM, const LogicalSize& aCBSize,
    nscoord aAvailableISize, const LogicalSize& aMargin,
    const LogicalSize& aBorderPadding, const StyleSizeOverrides& aSizeOverrides,
    ComputeSizeFlags aFlags) {
  if (GetPrevInFlow()) {
    // We're wrapping the text *after* the first letter, so behave like an
    // inline frame.
  return nsContainerFrame::ComputeSize(aRenderingContext, aWM, aCBSize,
                                       aAvailableISize, aMargin, aBorderPadding,
                                       aSizeOverrides, aFlags);

void nsFirstLetterFrame::Reflow(nsPresContext* aPresContext,
                                ReflowOutput& aMetrics,
                                const ReflowInput& aReflowInput,
                                nsReflowStatus& aReflowStatus) {
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aMetrics, aReflowStatus);
             "Caller should pass a fresh reflow status!");

  // Grab overflow list

  nsIFrame* kid = mFrames.FirstChild();

  // Setup reflow input for our child
  WritingMode wm = aReflowInput.GetWritingMode();
  LogicalSize availSize = aReflowInput.AvailableSize();
  const auto bp = aReflowInput.ComputedLogicalBorderPadding(wm);
               "should no longer use unconstrained inline size");
  availSize.ISize(wm) -= bp.IStartEnd(wm);
  if (NS_UNCONSTRAINEDSIZE != availSize.BSize(wm)) {
    availSize.BSize(wm) -= bp.BStartEnd(wm);

  WritingMode lineWM = aMetrics.GetWritingMode();
  ReflowOutput kidMetrics(lineWM);

  // Reflow the child
  if (!aReflowInput.mLineLayout) {
    // When there is no lineLayout provided, we provide our own. The
    // only time that the first-letter-frame is not reflowing in a
    // line context is when its floating.
    WritingMode kidWritingMode = WritingModeForLine(wm, kid);
    LogicalSize kidAvailSize = availSize.ConvertTo(kidWritingMode, wm);
    ReflowInput rs(aPresContext, aReflowInput, kid, kidAvailSize);
    nsLineLayout ll(aPresContext, nullptr, &aReflowInput, nullptr, nullptr);

        bp.IStart(wm), bp.BStart(wm), availSize.ISize(wm), NS_UNCONSTRAINEDSIZE,
        false, true, kidWritingMode,
        nsSize(aReflowInput.AvailableWidth(), aReflowInput.AvailableHeight()));
    rs.mLineLayout = &ll;

    kid->Reflow(aPresContext, kidMetrics, rs, aReflowStatus);


    // In the floating first-letter case, we need to set this ourselves;
    // nsLineLayout::BeginSpan will set it in the other case
    mBaseline = kidMetrics.BlockStartAscent();

    // Place and size the child and update the output metrics
    LogicalSize convertedSize = kidMetrics.Size(wm);
    kid->SetRect(nsRect(bp.IStart(wm), bp.BStart(wm), convertedSize.ISize(wm),
    kid->FinishAndStoreOverflow(&kidMetrics, rs.mStyleDisplay);
    kid->DidReflow(aPresContext, nullptr);

    convertedSize.ISize(wm) += bp.IStartEnd(wm);
    convertedSize.BSize(wm) += bp.BStartEnd(wm);
    aMetrics.SetSize(wm, convertedSize);
    aMetrics.SetBlockStartAscent(kidMetrics.BlockStartAscent() + bp.BStart(wm));

    // Ensure that the overflow rect contains the child textframe's
    // overflow rect.
    // Note that if this is floating, the overline/underline drawable
    // area is in the overflow rect of the child textframe.
    ConsiderChildOverflow(aMetrics.mOverflowAreas, kid);

    FinishAndStoreOverflow(&aMetrics, aReflowInput.mStyleDisplay);
  } else {
    // Pretend we are a span and reflow the child frame
    nsLineLayout* ll = aReflowInput.mLineLayout;
    bool pushedFrame;

    ll->SetInFirstLetter(Style()->GetPseudoType() ==
    ll->BeginSpan(this, &aReflowInput, bp.IStart(wm), availSize.ISize(wm),
    ll->ReflowFrame(kid, aReflowStatus, &kidMetrics, pushedFrame);
    NS_ASSERTION(lineWM.IsVertical() == wm.IsVertical(),
                 "we're assuming we can mix sizes between lineWM and wm "
                 "since we shouldn't have orthogonal writing modes within "
                 "a line.");
    aMetrics.ISize(lineWM) = ll->EndSpan(this) + bp.IStartEnd(wm);

    if (mComputedStyle->StyleTextReset()->mInitialLetterSize != 0.0f) {
      aMetrics.SetBlockStartAscent(kidMetrics.BlockStartAscent() +
      aMetrics.BSize(lineWM) = kidMetrics.BSize(lineWM) + bp.BStartEnd(wm);
    } else {
      nsLayoutUtils::SetBSizeFromFontMetrics(this, aMetrics, bp, lineWM, wm);

  if (!aReflowStatus.IsInlineBreakBefore()) {
    // Create a continuation or remove existing continuations based on
    // the reflow completion status.
    if (aReflowStatus.IsComplete()) {
      if (aReflowInput.mLineLayout) {
      nsIFrame* kidNextInFlow = kid->GetNextInFlow();
      if (kidNextInFlow) {
        // Remove all of the childs next-in-flows
        kidNextInFlow->GetParent()->DeleteNextInFlowChild(kidNextInFlow, true);
    } else {
      // Create a continuation for the child frame if it doesn't already
      // have one.
      if (!IsFloating()) {
        // And then push it to our overflow list
        nsFrameList overflow = mFrames.RemoveFramesAfter(kid);
        if (overflow.NotEmpty()) {
      } else if (!kid->GetNextInFlow()) {
        // For floating first letter frames (if a continuation wasn't already
        // created for us) we need to put the continuation with the rest of the
        // text that the first letter frame was made out of.
        nsIFrame* continuation;
        CreateContinuationForFloatingParent(kid, &continuation, true);

  NS_FRAME_SET_TRUNCATION(aReflowStatus, aReflowInput, aMetrics);

/* virtual */
bool nsFirstLetterFrame::CanContinueTextRun() const {
  // We can continue a text run through a first-letter frame.
  return true;

void nsFirstLetterFrame::CreateContinuationForFloatingParent(
    nsIFrame* aChild, nsIFrame** aContinuation, bool aIsFluid) {
               "can only call this on floating first letter frames");
  MOZ_ASSERT(aContinuation, "bad args");

  *aContinuation = nullptr;

  mozilla::PresShell* presShell = PresShell();
  nsPlaceholderFrame* placeholderFrame = GetPlaceholderFrame();
  nsContainerFrame* parent = placeholderFrame->GetParent();

  nsIFrame* continuation = presShell->FrameConstructor()->CreateContinuingFrame(
      aChild, parent, aIsFluid);

  // The continuation will have gotten the first letter style from its
  // prev continuation, so we need to repair the ComputedStyle so it
  // doesn't have the first letter styling.
  // Note that getting parent frame's ComputedStyle is different from getting
  // this frame's ComputedStyle's parent in the presence of ::first-line,
  // which we do want the continuation to inherit from.
  ComputedStyle* parentSC = parent->Style();
  if (parentSC) {
    RefPtr<ComputedStyle> newSC;
    newSC =

  // XXX Bidi may not be involved but we have to use the list name
  // kNoReflowPrincipalList because this is just like creating a continuation
  // except we have to insert it in a different place and we don't want a
  // reflow command to try to be issued.
  nsFrameList temp(continuation, continuation);
  parent->InsertFrames(kNoReflowPrincipalList, placeholderFrame, nullptr, temp);

  *aContinuation = continuation;

void nsFirstLetterFrame::DrainOverflowFrames(nsPresContext* aPresContext) {
  // Check for an overflow list with our prev-in-flow
  nsFirstLetterFrame* prevInFlow = (nsFirstLetterFrame*)GetPrevInFlow();
  if (prevInFlow) {
    AutoFrameListPtr overflowFrames(aPresContext,
    if (overflowFrames) {
      NS_ASSERTION(mFrames.IsEmpty(), "bad overflow list");

      // When pushing and pulling frames we need to check for whether any
      // views need to be reparented.
      nsContainerFrame::ReparentFrameViewList(*overflowFrames, prevInFlow,
      mFrames.InsertFrames(this, nullptr, *overflowFrames);

  // It's also possible that we have an overflow list for ourselves
  AutoFrameListPtr overflowFrames(aPresContext, StealOverflowFrames());
  if (overflowFrames) {
    NS_ASSERTION(mFrames.NotEmpty(), "overflow list w/o frames");
    mFrames.AppendFrames(nullptr, *overflowFrames);

  // Now repair our first frames ComputedStyle (since we only reflow
  // one frame there is no point in doing any other ones until they
  // are reflowed)
  nsIFrame* kid = mFrames.FirstChild();
  if (kid) {
    nsIContent* kidContent = kid->GetContent();
    if (kidContent) {
      NS_ASSERTION(kidContent->IsText(), "should contain only text nodes");
      ComputedStyle* parentSC;
      if (prevInFlow) {
        // This is for the rest of the content not in the first-letter.
        nsIFrame* styleParent =
            CorrectStyleParentFrame(GetParent(), PseudoStyleType::firstLetter);
        parentSC = styleParent->Style();
      } else {
        // And this for the first-letter style.
        parentSC = mComputedStyle;
      RefPtr<ComputedStyle> sc =
          aPresContext->StyleSet()->ResolveStyleForText(kidContent, parentSC);

nscoord nsFirstLetterFrame::GetLogicalBaseline(WritingMode aWritingMode) const {
  return mBaseline;

LogicalSides nsFirstLetterFrame::GetLogicalSkipSides() const {
  if (GetPrevContinuation()) {
    // We shouldn't get calls to GetSkipSides for later continuations since
    // they have separate ComputedStyles with initial values for all the
    // properties that could trigger a call to GetSkipSides.  Then again,
    // it's not really an error to call GetSkipSides on any frame, so
    // that's why we handle it properly.
    return LogicalSides(mWritingMode, eLogicalSideBitsAll);
  return LogicalSides(mWritingMode);  // first continuation displays all sides