tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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BRFrame.cpp (11367B)

      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 /* rendering object for HTML <br> elements */
      8 
      9 #include "gfxContext.h"
     10 #include "mozilla/CaretAssociationHint.h"
     11 #include "mozilla/PresShell.h"
     12 #include "mozilla/TextControlElement.h"
     13 #include "mozilla/dom/HTMLBRElement.h"
     14 #include "nsBlockFrame.h"
     15 #include "nsCOMPtr.h"
     16 #include "nsComputedDOMStyle.h"
     17 #include "nsContainerFrame.h"
     18 #include "nsFontMetrics.h"
     19 #include "nsGkAtoms.h"
     20 #include "nsHTMLParts.h"
     21 #include "nsIFrame.h"
     22 #include "nsLayoutUtils.h"
     23 #include "nsLineLayout.h"
     24 #include "nsPresContext.h"
     25 #include "nsStyleConsts.h"
     26 #include "nsTextFrame.h"
     27 
     28 // FOR SELECTION
     29 #include "nsIContent.h"
     30 // END INCLUDES FOR SELECTION
     31 
     32 using namespace mozilla;
     33 
     34 namespace mozilla {
     35 
     36 class BRFrame final : public nsIFrame {
     37 public:
     38  NS_DECL_FRAMEARENA_HELPERS(BRFrame)
     39 
     40  friend nsIFrame* ::NS_NewBRFrame(mozilla::PresShell* aPresShell,
     41                                   ComputedStyle* aStyle);
     42 
     43  ContentOffsets CalcContentOffsetsFromFramePoint(
     44      const nsPoint& aPoint) override;
     45 
     46  FrameSearchResult PeekOffsetNoAmount(bool aForward,
     47                                       int32_t* aOffset) override;
     48  FrameSearchResult PeekOffsetCharacter(
     49      bool aForward, int32_t* aOffset,
     50      PeekOffsetCharacterOptions aOptions =
     51          PeekOffsetCharacterOptions()) override;
     52  FrameSearchResult PeekOffsetWord(bool aForward, bool aWordSelectEatSpace,
     53                                   bool aIsKeyboardSelect, int32_t* aOffset,
     54                                   PeekWordState* aState,
     55                                   bool aTrimSpaces) override;
     56 
     57  void Reflow(nsPresContext* aPresContext, ReflowOutput& aMetrics,
     58              const ReflowInput& aReflowInput,
     59              nsReflowStatus& aStatus) override;
     60  void AddInlineMinISize(const IntrinsicSizeInput& aInput,
     61                         InlineMinISizeData* aData) override;
     62  void AddInlinePrefISize(const IntrinsicSizeInput& aInput,
     63                          InlinePrefISizeData* aData) override;
     64 
     65  Maybe<nscoord> GetNaturalBaselineBOffset(
     66      WritingMode aWM, BaselineSharingGroup aBaselineGroup,
     67      BaselineExportContext) const override;
     68 
     69 #ifdef ACCESSIBILITY
     70  mozilla::a11y::AccType AccessibleType() override;
     71 #endif
     72 
     73 #ifdef DEBUG_FRAME_DUMP
     74  nsresult GetFrameName(nsAString& aResult) const override {
     75    return MakeFrameName(u"BR"_ns, aResult);
     76  }
     77 #endif
     78 
     79 protected:
     80  BRFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
     81      : nsIFrame(aStyle, aPresContext, kClassID),
     82        mAscent(NS_INTRINSIC_ISIZE_UNKNOWN) {}
     83 
     84  virtual ~BRFrame();
     85 
     86  nscoord mAscent;
     87 };
     88 
     89 }  // namespace mozilla
     90 
     91 nsIFrame* NS_NewBRFrame(mozilla::PresShell* aPresShell, ComputedStyle* aStyle) {
     92  return new (aPresShell) BRFrame(aStyle, aPresShell->GetPresContext());
     93 }
     94 
     95 NS_IMPL_FRAMEARENA_HELPERS(BRFrame)
     96 
     97 BRFrame::~BRFrame() = default;
     98 
     99 void BRFrame::Reflow(nsPresContext* aPresContext, ReflowOutput& aMetrics,
    100                     const ReflowInput& aReflowInput, nsReflowStatus& aStatus) {
    101  MarkInReflow();
    102  DO_GLOBAL_REFLOW_COUNT("BRFrame");
    103  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
    104 
    105  WritingMode wm = aReflowInput.GetWritingMode();
    106  LogicalSize finalSize(wm);
    107  finalSize.BSize(wm) = 0;  // BR frames with block size 0 are ignored in quirks
    108                            // mode by nsLineLayout::VerticalAlignFrames .
    109                            // However, it's not always 0.  See below.
    110  finalSize.ISize(wm) = 0;
    111  aMetrics.SetBlockStartAscent(0);
    112 
    113  // Only when the BR is operating in a line-layout situation will it
    114  // behave like a BR. Additionally, we suppress breaks from BR inside
    115  // of ruby frames. To determine if we're inside ruby, we have to rely
    116  // on the *parent's* ShouldSuppressLineBreak() method, instead of our
    117  // own, because we may have custom "display" value that makes our
    118  // ShouldSuppressLineBreak() return false.
    119  nsLineLayout* ll = aReflowInput.mLineLayout;
    120  if (ll && !GetParent()->Style()->ShouldSuppressLineBreak()) {
    121    // Note that the compatibility mode check excludes AlmostStandards
    122    // mode, since this is the inline box model.  See bug 161691.
    123    if (ll->LineIsEmpty() ||
    124        aPresContext->CompatibilityMode() == eCompatibility_FullStandards) {
    125      // The line is logically empty; any whitespace is trimmed away.
    126      //
    127      // If this frame is going to terminate the line we know
    128      // that nothing else will go on the line. Therefore, in this
    129      // case, we provide some height for the BR frame so that it
    130      // creates some vertical whitespace.  It's necessary to use the
    131      // line-height rather than the font size because the
    132      // quirks-mode fix that doesn't apply the block's min
    133      // line-height makes this necessary to make BR cause a line
    134      // of the full line-height
    135 
    136      // We also do this in strict mode because BR should act like a
    137      // normal inline frame.  That line-height is used is important
    138      // here for cases where the line-height is less than 1.
    139      RefPtr<nsFontMetrics> fm =
    140          nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
    141      if (fm) {
    142        nscoord logicalHeight = aReflowInput.GetLineHeight();
    143        finalSize.BSize(wm) = logicalHeight;
    144        aMetrics.SetBlockStartAscent(nsLayoutUtils::GetCenteredFontBaseline(
    145            fm, logicalHeight, wm.IsLineInverted()));
    146      } else {
    147        aMetrics.SetBlockStartAscent(aMetrics.BSize(wm) = 0);
    148      }
    149    }
    150 
    151    // Return our reflow status
    152    aStatus.SetInlineLineBreakAfter(
    153        aReflowInput.mStyleDisplay->UsedClear(aReflowInput.GetCBWritingMode()));
    154    ll->SetLineEndsInBR(true);
    155  }
    156 
    157  aMetrics.SetSize(wm, finalSize);
    158  aMetrics.SetOverflowAreasToDesiredBounds();
    159 
    160  mAscent = aMetrics.BlockStartAscent();
    161 }
    162 
    163 /* virtual */
    164 void BRFrame::AddInlineMinISize(const IntrinsicSizeInput& aInput,
    165                                InlineMinISizeData* aData) {
    166  if (!GetParent()->Style()->ShouldSuppressLineBreak()) {
    167    aData->ForceBreak();
    168  }
    169 }
    170 
    171 /* virtual */
    172 void BRFrame::AddInlinePrefISize(const IntrinsicSizeInput& aInput,
    173                                 InlinePrefISizeData* aData) {
    174  if (!GetParent()->Style()->ShouldSuppressLineBreak()) {
    175    aData->ForceBreak();
    176  }
    177 }
    178 
    179 Maybe<nscoord> BRFrame::GetNaturalBaselineBOffset(
    180    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
    181    BaselineExportContext) const {
    182  if (aBaselineGroup == BaselineSharingGroup::Last) {
    183    return Nothing{};
    184  }
    185  return Some(mAscent);
    186 }
    187 
    188 nsIFrame::ContentOffsets BRFrame::CalcContentOffsetsFromFramePoint(
    189    const nsPoint& aPoint) {
    190  ContentOffsets offsets;
    191  offsets.content = mContent->GetParent();
    192  if (offsets.content) {
    193    offsets.offset = offsets.content->ComputeIndexOf_Deprecated(mContent);
    194    offsets.secondaryOffset = offsets.offset;
    195    offsets.associate = CaretAssociationHint::After;
    196  }
    197  return offsets;
    198 }
    199 
    200 nsIFrame::FrameSearchResult BRFrame::PeekOffsetNoAmount(bool aForward,
    201                                                        int32_t* aOffset) {
    202  NS_ASSERTION(aOffset && *aOffset <= 1, "aOffset out of range");
    203  int32_t startOffset = *aOffset;
    204  // If we hit the end of a BR going backwards, go to its beginning and stay
    205  // there.
    206  if (!aForward && startOffset != 0) {
    207    *aOffset = 0;
    208    return FOUND;
    209  }
    210  // Otherwise, stop if we hit the beginning, continue (forward) if we hit the
    211  // end.
    212  return (startOffset == 0) ? FOUND : CONTINUE;
    213 }
    214 
    215 nsIFrame::FrameSearchResult BRFrame::PeekOffsetCharacter(
    216    bool aForward, int32_t* aOffset, PeekOffsetCharacterOptions aOptions) {
    217  NS_ASSERTION(aOffset && *aOffset <= 1, "aOffset out of range");
    218  // Keep going. The actual line jumping will stop us.
    219  return CONTINUE;
    220 }
    221 
    222 nsIFrame::FrameSearchResult BRFrame::PeekOffsetWord(
    223    bool aForward, bool aWordSelectEatSpace, bool aIsKeyboardSelect,
    224    int32_t* aOffset, PeekWordState* aState, bool aTrimSpaces) {
    225  NS_ASSERTION(aOffset && *aOffset <= 1, "aOffset out of range");
    226  // Keep going. The actual line jumping will stop us.
    227  return CONTINUE;
    228 }
    229 
    230 #ifdef ACCESSIBILITY
    231 a11y::AccType BRFrame::AccessibleType() {
    232  dom::HTMLBRElement* brElement = dom::HTMLBRElement::FromNode(mContent);
    233 
    234  if (!brElement->IsPaddingForEmptyLastLine()) {
    235    // Even if this <br> is a "padding <br> element" used when there is no text
    236    // in an editor, it may be surrounded by before/after pseudo element
    237    // content. Therefore, we need to treat it as a normal <br>.
    238    return a11y::eHTMLBRType;
    239  }
    240 
    241  // If it's a padding <br> element used in the anonymous subtree of <textarea>,
    242  // we don't need to expose it as a line break because of in an replaced
    243  // content.
    244  if (brElement->IsInNativeAnonymousSubtree()) {
    245    const auto* textControlElement = TextControlElement::FromNodeOrNull(
    246        brElement->GetClosestNativeAnonymousSubtreeRootParentOrHost());
    247    if (textControlElement &&
    248        textControlElement->IsSingleLineTextControlOrTextArea()) {
    249      return a11y::eNoType;
    250    }
    251  }
    252 
    253  // If this <br> is a "padding <br> element" used when there is an empty last
    254  // line before a block boundary in an HTML editor, this is required only for
    255  // the empty last line visible in the CSS layout world.  Therefore, this is
    256  // meaningless so that this should not appear in the flattened text.  On the
    257  // other hand, if this is a padding <br> element used when there is no
    258  // visible things in the parent block in an editor, this is required to give
    259  // one-line height to the block.  So, basically, this is meaningless, but
    260  // this may be surrounded by before/after pseudo content.  Then, they appear
    261  // in different lines because of this line break.  So, this is not meaningless
    262  // in such case.  For now, we should treat this is meaningless only in the
    263  // former case.  We can assume that if this is a padding <br>, it directly
    264  // follows a block boundary because our editor does not keep empty nodes at
    265  // least intentionally.
    266  // XXX This does not treat complicated layout cases.  However, our editor
    267  // must not work well with such layout.  So, this should be okay for the
    268  // web apps in the wild.
    269  nsIFrame* const parentFrame = GetParent();
    270  if (HasAnyStateBits(NS_FRAME_OUT_OF_FLOW) || !parentFrame) {
    271    return a11y::eHTMLBRType;
    272  }
    273  nsIFrame* const currentBlock =
    274      nsBlockFrame::GetNearestAncestorBlock(parentFrame);
    275  nsIContent* const currentBlockContent =
    276      currentBlock ? currentBlock->GetContent() : nullptr;
    277  for (nsIContent* previousContent =
    278           brElement->GetPrevNode(currentBlockContent);
    279       previousContent;
    280       previousContent = previousContent->GetPrevNode(currentBlockContent)) {
    281    nsIFrame* const precedingContentFrame = previousContent->GetPrimaryFrame();
    282    if (!precedingContentFrame || precedingContentFrame->IsEmpty()) {
    283      continue;
    284    }
    285    if (precedingContentFrame->IsBlockFrameOrSubclass()) {
    286      break;  // Reached a child block.
    287    }
    288    // FIXME: Oh, this should be a11y::eNoType because it's a meaningless <br>.
    289    return a11y::eHTMLBRType;
    290  }
    291  return a11y::eHTMLBRType;
    292 }
    293 
    294 #endif