1 files changed, 269 insertions, 0 deletions
diff --git a/layout/generic/BRFrame.cpp b/layout/generic/BRFrame.cpp
new file mode 100644
index 0000000000..5cb7c104d9
--- /dev/null
+++ b/layout/generic/BRFrame.cpp
@@ -0,0 +1,269 @@
+/* -*- 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 HTML <br> elements */
+
+#include "mozilla/PresShell.h"
+#include "mozilla/dom/HTMLBRElement.h"
+#include "gfxContext.h"
+#include "nsCOMPtr.h"
+#include "nsContainerFrame.h"
+#include "nsFontMetrics.h"
+#include "nsHTMLParts.h"
+#include "nsIFrame.h"
+#include "nsPresContext.h"
+#include "nsLineLayout.h"
+#include "nsStyleConsts.h"
+#include "nsGkAtoms.h"
+#include "nsLayoutUtils.h"
+
+// FOR SELECTION
+#include "nsIContent.h"
+// END INCLUDES FOR SELECTION
+
+using namespace mozilla;
+
+namespace mozilla {
+
+class BRFrame final : public nsIFrame {
+ public:
+  NS_DECL_FRAMEARENA_HELPERS(BRFrame)
+
+  friend nsIFrame* ::NS_NewBRFrame(mozilla::PresShell* aPresShell,
+                                   ComputedStyle* aStyle);
+
+  ContentOffsets CalcContentOffsetsFromFramePoint(
+      const nsPoint& aPoint) override;
+
+  FrameSearchResult PeekOffsetNoAmount(bool aForward,
+                                       int32_t* aOffset) override;
+  FrameSearchResult PeekOffsetCharacter(
+      bool aForward, int32_t* aOffset,
+      PeekOffsetCharacterOptions aOptions =
+          PeekOffsetCharacterOptions()) override;
+  FrameSearchResult PeekOffsetWord(bool aForward, bool aWordSelectEatSpace,
+                                   bool aIsKeyboardSelect, int32_t* aOffset,
+                                   PeekWordState* aState,
+                                   bool aTrimSpaces) override;
+
+  void Reflow(nsPresContext* aPresContext, ReflowOutput& aMetrics,
+              const ReflowInput& aReflowInput,
+              nsReflowStatus& aStatus) override;
+  void AddInlineMinISize(gfxContext* aRenderingContext,
+                         InlineMinISizeData* aData) override;
+  void AddInlinePrefISize(gfxContext* aRenderingContext,
+                          InlinePrefISizeData* aData) override;
+  nscoord GetMinISize(gfxContext* aRenderingContext) override;
+  nscoord GetPrefISize(gfxContext* aRenderingContext) override;
+
+  Maybe<nscoord> GetNaturalBaselineBOffset(
+      WritingMode aWM, BaselineSharingGroup aBaselineGroup,
+      BaselineExportContext) const override;
+
+  bool IsFrameOfType(uint32_t aFlags) const override {
+    return nsIFrame::IsFrameOfType(
+        aFlags & ~(nsIFrame::eReplaced | nsIFrame::eLineParticipant));
+  }
+
+#ifdef ACCESSIBILITY
+  mozilla::a11y::AccType AccessibleType() override;
+#endif
+
+#ifdef DEBUG_FRAME_DUMP
+  nsresult GetFrameName(nsAString& aResult) const override {
+    return MakeFrameName(u"BR"_ns, aResult);
+  }
+#endif
+
+ protected:
+  BRFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
+      : nsIFrame(aStyle, aPresContext, kClassID),
+        mAscent(NS_INTRINSIC_ISIZE_UNKNOWN) {}
+
+  virtual ~BRFrame();
+
+  nscoord mAscent;
+};
+
+}  // namespace mozilla
+
+nsIFrame* NS_NewBRFrame(mozilla::PresShell* aPresShell, ComputedStyle* aStyle) {
+  return new (aPresShell) BRFrame(aStyle, aPresShell->GetPresContext());
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(BRFrame)
+
+BRFrame::~BRFrame() = default;
+
+void BRFrame::Reflow(nsPresContext* aPresContext, ReflowOutput& aMetrics,
+                     const ReflowInput& aReflowInput, nsReflowStatus& aStatus) {
+  MarkInReflow();
+  DO_GLOBAL_REFLOW_COUNT("BRFrame");
+  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aMetrics, aStatus);
+  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+
+  WritingMode wm = aReflowInput.GetWritingMode();
+  LogicalSize finalSize(wm);
+  finalSize.BSize(wm) = 0;  // BR frames with block size 0 are ignored in quirks
+                            // mode by nsLineLayout::VerticalAlignFrames .
+                            // However, it's not always 0.  See below.
+  finalSize.ISize(wm) = 0;
+  aMetrics.SetBlockStartAscent(0);
+
+  // Only when the BR is operating in a line-layout situation will it
+  // behave like a BR. Additionally, we suppress breaks from BR inside
+  // of ruby frames. To determine if we're inside ruby, we have to rely
+  // on the *parent's* ShouldSuppressLineBreak() method, instead of our
+  // own, because we may have custom "display" value that makes our
+  // ShouldSuppressLineBreak() return false.
+  nsLineLayout* ll = aReflowInput.mLineLayout;
+  if (ll && !GetParent()->Style()->ShouldSuppressLineBreak()) {
+    // Note that the compatibility mode check excludes AlmostStandards
+    // mode, since this is the inline box model.  See bug 161691.
+    if (ll->LineIsEmpty() ||
+        aPresContext->CompatibilityMode() == eCompatibility_FullStandards) {
+      // The line is logically empty; any whitespace is trimmed away.
+      //
+      // If this frame is going to terminate the line we know
+      // that nothing else will go on the line. Therefore, in this
+      // case, we provide some height for the BR frame so that it
+      // creates some vertical whitespace.  It's necessary to use the
+      // line-height rather than the font size because the
+      // quirks-mode fix that doesn't apply the block's min
+      // line-height makes this necessary to make BR cause a line
+      // of the full line-height
+
+      // We also do this in strict mode because BR should act like a
+      // normal inline frame.  That line-height is used is important
+      // here for cases where the line-height is less than 1.
+      RefPtr<nsFontMetrics> fm =
+          nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
+      if (fm) {
+        nscoord logicalHeight = aReflowInput.GetLineHeight();
+        finalSize.BSize(wm) = logicalHeight;
+        aMetrics.SetBlockStartAscent(nsLayoutUtils::GetCenteredFontBaseline(
+            fm, logicalHeight, wm.IsLineInverted()));
+      } else {
+        aMetrics.SetBlockStartAscent(aMetrics.BSize(wm) = 0);
+      }
+
+      // XXX temporary until I figure out a better solution; see the
+      // code in nsLineLayout::VerticalAlignFrames that zaps minY/maxY
+      // if the width is zero.
+      // XXX This also fixes bug 10036!
+      // Warning: nsTextControlFrame::CalculateSizeStandard depends on
+      // the following line, see bug 228752.
+      // The code below in AddInlinePrefISize also adds 1 appunit to width
+      finalSize.ISize(wm) = 1;
+    }
+
+    // Return our reflow status
+    aStatus.SetInlineLineBreakAfter(aReflowInput.mStyleDisplay->mClear);
+    ll->SetLineEndsInBR(true);
+  }
+
+  aMetrics.SetSize(wm, finalSize);
+  aMetrics.SetOverflowAreasToDesiredBounds();
+
+  mAscent = aMetrics.BlockStartAscent();
+}
+
+/* virtual */
+void BRFrame::AddInlineMinISize(gfxContext* aRenderingContext,
+                                nsIFrame::InlineMinISizeData* aData) {
+  if (!GetParent()->Style()->ShouldSuppressLineBreak()) {
+    aData->ForceBreak();
+  }
+}
+
+/* virtual */
+void BRFrame::AddInlinePrefISize(gfxContext* aRenderingContext,
+                                 nsIFrame::InlinePrefISizeData* aData) {
+  if (!GetParent()->Style()->ShouldSuppressLineBreak()) {
+    // Match the 1 appunit width assigned in the Reflow method above
+    aData->mCurrentLine += 1;
+    aData->ForceBreak();
+  }
+}
+
+/* virtual */
+nscoord BRFrame::GetMinISize(gfxContext* aRenderingContext) {
+  nscoord result = 0;
+  DISPLAY_MIN_INLINE_SIZE(this, result);
+  return result;
+}
+
+/* virtual */
+nscoord BRFrame::GetPrefISize(gfxContext* aRenderingContext) {
+  nscoord result = 0;
+  DISPLAY_PREF_INLINE_SIZE(this, result);
+  return result;
+}
+
+Maybe<nscoord> BRFrame::GetNaturalBaselineBOffset(
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
+    BaselineExportContext) const {
+  if (aBaselineGroup == BaselineSharingGroup::Last) {
+    return Nothing{};
+  }
+  return Some(mAscent);
+}
+
+nsIFrame::ContentOffsets BRFrame::CalcContentOffsetsFromFramePoint(
+    const nsPoint& aPoint) {
+  ContentOffsets offsets;
+  offsets.content = mContent->GetParent();
+  if (offsets.content) {
+    offsets.offset = offsets.content->ComputeIndexOf_Deprecated(mContent);
+    offsets.secondaryOffset = offsets.offset;
+    offsets.associate = CARET_ASSOCIATE_AFTER;
+  }
+  return offsets;
+}
+
+nsIFrame::FrameSearchResult BRFrame::PeekOffsetNoAmount(bool aForward,
+                                                        int32_t* aOffset) {
+  NS_ASSERTION(aOffset && *aOffset <= 1, "aOffset out of range");
+  int32_t startOffset = *aOffset;
+  // If we hit the end of a BR going backwards, go to its beginning and stay
+  // there.
+  if (!aForward && startOffset != 0) {
+    *aOffset = 0;
+    return FOUND;
+  }
+  // Otherwise, stop if we hit the beginning, continue (forward) if we hit the
+  // end.
+  return (startOffset == 0) ? FOUND : CONTINUE;
+}
+
+nsIFrame::FrameSearchResult BRFrame::PeekOffsetCharacter(
+    bool aForward, int32_t* aOffset, PeekOffsetCharacterOptions aOptions) {
+  NS_ASSERTION(aOffset && *aOffset <= 1, "aOffset out of range");
+  // Keep going. The actual line jumping will stop us.
+  return CONTINUE;
+}
+
+nsIFrame::FrameSearchResult BRFrame::PeekOffsetWord(
+    bool aForward, bool aWordSelectEatSpace, bool aIsKeyboardSelect,
+    int32_t* aOffset, PeekWordState* aState, bool aTrimSpaces) {
+  NS_ASSERTION(aOffset && *aOffset <= 1, "aOffset out of range");
+  // Keep going. The actual line jumping will stop us.
+  return CONTINUE;
+}
+
+#ifdef ACCESSIBILITY
+a11y::AccType BRFrame::AccessibleType() {
+  dom::HTMLBRElement* brElement = dom::HTMLBRElement::FromNode(mContent);
+  if (brElement->IsPaddingForEmptyEditor() ||
+      brElement->IsPaddingForEmptyLastLine()) {
+    // This <br> is a "padding <br> element" used when there is no text or an
+    // empty last line in an editor.
+    return a11y::eNoType;
+  }
+
+  return a11y::eHTMLBRType;
+}
+#endif