Bug 1931466: Ensure inline elements in an empty linebox as having zero BSize and no baseline. r=layout-reviewers,dholbert,jfkthame

Differential Revision: https://phabricator.services.mozilla.com/D229191
2024-11-23 04:41:11 +00:00 · 2024-11-19 19:39:21 +00:00 · 2024-11-19 19:39:21 +00:00 · 429486d08f
commit 429486d08f
parent 8f4f441cae
17 changed files with 169 additions and 33 deletions
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@ -4990,7 +4990,10 @@ void nsBlockFrame::DoReflowInlineFrames(

  aLineLayout.BeginLineReflow(
      iStart, aState.mBCoord, availISize, availBSize,
-      aFloatAvailableSpace.HasFloats(), false, /*XXX isTopOfPage*/
+      aFloatAvailableSpace.HasFloats(), false /*XXX isTopOfPage*/,
+      HasOutsideMarker() || Style()->IsAnonBox()
+          ? CollapseEmptyInlineFramesInLine::Preserve
+          : CollapseEmptyInlineFramesInLine::Collapse,
      lineWM, aState.mContainerSize, aState.mInsetForBalance);

  aState.mFlags.mIsLineLayoutEmpty = false;
--- a/layout/generic/nsFirstLetterFrame.cpp
+++ b/layout/generic/nsFirstLetterFrame.cpp
@ -222,9 +222,11 @@ void nsFirstLetterFrame::Reflow(nsPresContext* aPresContext,
    ReflowInput rs(aPresContext, aReflowInput, kid, kidAvailSize);
    nsLineLayout ll(aPresContext, nullptr, aReflowInput, nullptr, nullptr);

+    // This frame does not get constructed for an empty inline frame, so
+    // `CollapseEmptyInlineFramesInLine` should not matter.
    ll.BeginLineReflow(
        bp.IStart(wm), bp.BStart(wm), availSize.ISize(wm), NS_UNCONSTRAINEDSIZE,
-        false, true, kidWritingMode,
+        false, true, CollapseEmptyInlineFramesInLine::Collapse, kidWritingMode,
        nsSize(aReflowInput.AvailableWidth(), aReflowInput.AvailableHeight()));
    rs.mLineLayout = &ll;
    ll.SetInFirstLetter(true);
--- a/layout/generic/nsInlineFrame.cpp
+++ b/layout/generic/nsInlineFrame.cpp
@ -850,6 +850,8 @@ Maybe<nscoord> nsInlineFrame::GetNaturalBaselineBOffset(
  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);
 }

--- a/layout/generic/nsLineLayout.cpp
+++ b/layout/generic/nsLineLayout.cpp
@ -91,12 +91,11 @@ nsLineLayout::nsLineLayout(nsPresContext* aPresContext,
  }
 }

-void nsLineLayout::BeginLineReflow(nscoord aICoord, nscoord aBCoord,
-                                   nscoord aISize, nscoord aBSize,
-                                   bool aImpactedByFloats, bool aIsTopOfPage,
-                                   WritingMode aWritingMode,
-                                   const nsSize& aContainerSize,
-                                   nscoord aInset) {
+void nsLineLayout::BeginLineReflow(
+    nscoord aICoord, nscoord aBCoord, nscoord aISize, nscoord aBSize,
+    bool aImpactedByFloats, bool aIsTopOfPage,
+    CollapseEmptyInlineFramesInLine aCollapseEmptyInlineFramesInLine,
+    WritingMode aWritingMode, const nsSize& aContainerSize, nscoord aInset) {
  MOZ_ASSERT(nullptr == mRootSpan, "bad linelayout user");
  LAYOUT_WARN_IF_FALSE(aISize != NS_UNCONSTRAINEDSIZE,
                       "have unconstrained width; this should only result from "
@ -149,6 +148,9 @@ void nsLineLayout::BeginLineReflow(nscoord aICoord, nscoord aBCoord,
  psd->mIStart = aICoord;
  psd->mICoord = aICoord;
  psd->mIEnd = aICoord + aISize;
+  psd->mDoCollapseEmptyInlineFramesInLine =
+      aCollapseEmptyInlineFramesInLine ==
+      CollapseEmptyInlineFramesInLine::Collapse;
  // Set up inset to be used for text-wrap:balance implementation, but only if
  // the available size is greater than inset.
  psd->mInset = aISize > aInset ? aInset : 0;
@ -354,6 +356,7 @@ nsLineLayout::PerSpanData* nsLineLayout::NewPerSpanData() {
  psd->mContainsFloat = false;
  psd->mHasNonemptyContent = false;
  psd->mBaseline = nullptr;
+  psd->mDoCollapseEmptyInlineFramesInLine = false;

 #ifdef DEBUG
  outerLineLayout->mSpansAllocated++;
@ -1490,6 +1493,34 @@ void nsLineLayout::VerticalAlignLine() {
  // this operation is set to zero so that the y coordinates for all
  // of the placed children will be relative to there.
  PerSpanData* psd = mRootSpan;
+  if (mLineIsEmpty && psd->mDoCollapseEmptyInlineFramesInLine) {
+    // This line is empty, and should be consisting of only inline elements.
+    // (inline-block elements would make the line non-empty).
+    WritingMode lineWM = psd->mWritingMode;
+    for (PerFrameData* pfd = psd->mFirstFrame; pfd; pfd = pfd->mNext) {
+      // Ideally, if the frame would collapse itself - but it depends on
+      // knowing that the line is empty.
+      if (!pfd->mFrame->IsInlineFrame() && !pfd->mFrame->IsRubyFrame()) {
+        continue;
+      }
+      // Collapse the physical size to 0.
+      pfd->mBounds.BStart(lineWM) = mBStartEdge;
+      pfd->mBounds.BSize(lineWM) = 0;
+      // Initialize mBlockDirAlign (though it doesn't make much difference
+      // because we don't align empty boxes).
+      pfd->mBlockDirAlign = VALIGN_OTHER;
+      pfd->mFrame->SetRect(lineWM, pfd->mBounds, ContainerSize());
+    }
+
+    mFinalLineBSize = 0;
+    if (mGotLineBox) {
+      mLineBox->SetBounds(psd->mWritingMode, psd->mIStart, mBStartEdge,
+                          psd->mICoord - psd->mIStart, 0, ContainerSize());
+
+      mLineBox->SetLogicalAscent(0);
+    }
+    return;
+  }
  VerticalAlignFrames(psd);

  // *** Note that comments here still use the anachronistic term
--- a/layout/generic/nsLineLayout.h
+++ b/layout/generic/nsLineLayout.h
@ -20,6 +20,18 @@
 class nsFloatManager;
 struct nsStyleText;

+/**
+ * Flag indicating if inline frames within a line should be collapsed
+ * to zero block-size if all frames within it are empty.
+ * Declared as typed enum for clearer semantics in function calls, though
+ * it is reflected as a boolean in
+ * PerSpanData::mDoCollapseEmptyInlineFramesInLine.
+ */
+enum class CollapseEmptyInlineFramesInLine {
+  Preserve,
+  Collapse,
+};
+
 class nsLineLayout {
  using BlockReflowState = mozilla::BlockReflowState;
  using ReflowInput = mozilla::ReflowInput;
@ -49,13 +61,14 @@ class nsLineLayout {

  int32_t GetLineNumber() const { return mLineNumber; }

-  void BeginLineReflow(nscoord aICoord, nscoord aBCoord, nscoord aISize,
-                       nscoord aBSize, bool aImpactedByFloats,
-                       bool aIsTopOfPage, mozilla::WritingMode aWritingMode,
-                       const nsSize& aContainerSize,
-                       // aInset is used during text-wrap:balance to reduce
-                       // the effective available space on the line.
-                       nscoord aInset = 0);
+  void BeginLineReflow(
+      nscoord aICoord, nscoord aBCoord, nscoord aISize, nscoord aBSize,
+      bool aImpactedByFloats, bool aIsTopOfPage,
+      CollapseEmptyInlineFramesInLine aCollapseEmptyInlineFramesInLine,
+      mozilla::WritingMode aWritingMode, const nsSize& aContainerSize,
+      // aInset is used during text-wrap:balance to reduce
+      // the effective available space on the line.
+      nscoord aInset = 0);

  /**
   * Returns true if the line had to use an overflow-wrap break position.
@ -497,6 +510,7 @@ class nsLineLayout {
    mozilla::WritingMode mWritingMode;
    bool mContainsFloat;
    bool mHasNonemptyContent;
+    bool mDoCollapseEmptyInlineFramesInLine;

    nscoord mIStart;
    nscoord mICoord;
--- a/layout/generic/nsRubyBaseContainerFrame.cpp
+++ b/layout/generic/nsRubyBaseContainerFrame.cpp
@ -341,9 +341,9 @@ void nsRubyBaseContainerFrame::Reflow(nsPresContext* aPresContext,
    // If the writing mode is vertical-rl, the horizontal position of
    // rt frames will be updated when reflowing this text container,
    // hence leave container size 0 here for now.
-    lineLayout->BeginLineReflow(0, 0, reflowInput->ComputedISize(),
-                                NS_UNCONSTRAINEDSIZE, false, false, reflowWM,
-                                nsSize(0, 0));
+    lineLayout->BeginLineReflow(
+        0, 0, reflowInput->ComputedISize(), NS_UNCONSTRAINEDSIZE, false, false,
+        CollapseEmptyInlineFramesInLine::Collapse, reflowWM, nsSize(0, 0));
    lineLayout->AttachRootFrameToBaseLineLayout();
  }

--- a/layout/reftests/css-ui/caret-color-01-ref.html
+++ b/layout/reftests/css-ui/caret-color-01-ref.html
@ -10,7 +10,7 @@ div {
  background: green;
 }
 </style>
-<div><span></span></div>
+<div><span>&nbsp;</span></div>
 <script>
 let $div = document.querySelector('div');
 let $span = document.querySelector('span');
--- a/layout/reftests/css-visited/caret-color-on-visited-1-ref.html
+++ b/layout/reftests/css-visited/caret-color-on-visited-1-ref.html
@ -10,7 +10,7 @@ div {
  background: green;
 }
 </style>
-<div><span></span></div>
+<div><span>&nbsp;</span></div>
 <script>
 let $div = document.querySelector('div');
 let $span = document.querySelector('span');
--- a/testing/web-platform/meta/FileAPI/url/url-in-tags.window.js.ini
+++ b/testing/web-platform/meta/FileAPI/url/url-in-tags.window.js.ini
@ -2,5 +2,3 @@
  max-asserts: 3
  expected:
    if (os == "android") and fission: [OK, TIMEOUT]
-  [Blob URL fragment is implemented.]
-    expected: FAIL
--- a/testing/web-platform/meta/css/CSS2/positioning/abspos-inline-008.xht.ini
+++ b/testing/web-platform/meta/css/CSS2/positioning/abspos-inline-008.xht.ini
@ -1,2 +0,0 @@
-[abspos-inline-008.xht]
-  expected: FAIL
--- a/testing/web-platform/meta/css/CSS2/positioning/toogle-abspos-on-relpos-inline-child.html.ini
+++ b/testing/web-platform/meta/css/CSS2/positioning/toogle-abspos-on-relpos-inline-child.html.ini
@ -1,2 +0,0 @@
-[toogle-abspos-on-relpos-inline-child.html]
-  expected: FAIL
--- a/testing/web-platform/meta/css/css-break/out-of-flow-in-multicolumn-116.html.ini
+++ b/testing/web-platform/meta/css/css-break/out-of-flow-in-multicolumn-116.html.ini
@ -1,2 +0,0 @@
-[out-of-flow-in-multicolumn-116.html]
-  expected: FAIL
--- a/testing/web-platform/meta/css/css-position/position-absolute-in-inline-001.html.ini
+++ b/testing/web-platform/meta/css/css-position/position-absolute-in-inline-001.html.ini
@ -1,5 +0,0 @@
-[position-absolute-in-inline-001.html]
-  expected:
-    if (os == "android") and fission: [OK, TIMEOUT]
-  [absolute inside inline container location should be correct.]
-    expected: FAIL
--- a/testing/web-platform/tests/css/css-inline/empty-span-size-001-ref.html
+++ b/testing/web-platform/tests/css/css-inline/empty-span-size-001-ref.html
@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<link rel="author" title="David Shin" href="mailto:dshin@mozilla.com">
+<link rel="help" href="https://drafts.csswg.org/css-inline-3/#invisible-line-boxes">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1931466">
+<style>
+.container {
+  border: 1px solid;
+}
+
+ul {
+  margin: 0;
+}
+
+.button {
+  box-sizing: border-box;
+  border-left: 1px solid;
+  width: 1px;
+  height: 11px;
+  display: inline-block;
+  vertical-align: top;
+}
+</style>
+<div class="container"></div><br>
+<div class="container"><span style="border: 1px solid; border-right: 2px solid;"></span></div><br>
+<div class="container"><ul><li>&nbsp;</li><li>&nbsp;</li></ul></div><br>
+<div class="container"><div class="button"></div><span>&nbsp;</span></div><br>
--- a/testing/web-platform/tests/css/css-inline/empty-span-size-001.html
+++ b/testing/web-platform/tests/css/css-inline/empty-span-size-001.html
@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<link rel="author" title="David Shin" href="mailto:dshin@mozilla.com">
+<link rel="help" href="https://drafts.csswg.org/css-inline-3/#invisible-line-boxes">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1931466">
+<link rel="match" href="empty-span-size-001-ref.html">
+<style>
+.container, .has-height {
+  border: 1px solid;
+}
+
+.inline {
+  outline: 1px solid;
+}
+
+input {
+  outline: 1px solid;
+  background: transparent;
+  padding: 0;
+  border: 0;
+  line-height: 10px;
+  vertical-align: top;
+}
+
+ul {
+  margin: 0;
+}
+
+li {
+  width: 0;
+}
+</style>
+<!-- Empty inline element in empty line has a height of zero. -->
+<div class="container"><span class="inline"></span></div><br>
+<!-- ... But not if the line has a meaningful height. -->
+<div class="container"><span class="inline"></span><span class="has-height"></span><span class="inline"></span></div><br>
+<!-- ... Or if the line is present in some kind of context that gives a meaningful height. -->
+<div class="container"><ul><li></li><li></li></ul></div><br>
+<div class="container"><input type="button" value=""></div><br>
--- a/testing/web-platform/tests/css/css-inline/empty-span-size-002-ref.html
+++ b/testing/web-platform/tests/css/css-inline/empty-span-size-002-ref.html
@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<link rel="author" title="David Shin" href="mailto:dshin@mozilla.com">
+<link rel="help" href="https://drafts.csswg.org/css-inline-3/#invisible-line-boxes">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1931466">
+<style>
+.container {
+  border: 1px solid;
+}
+
+ul {
+  margin: 0;
+}
+</style>
+<div class="container"></div><br>
+<div class="container"><span style="border: 1px solid; border-right: 2px solid;"></span></div><br>
--- a/testing/web-platform/tests/css/css-inline/empty-span-size-002.html
+++ b/testing/web-platform/tests/css/css-inline/empty-span-size-002.html
@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<link rel="author" title="David Shin" href="mailto:dshin@mozilla.com">
+<link rel="help" href="https://drafts.csswg.org/css-inline-3/#invisible-line-boxes">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1931466">
+<link rel="match" href="empty-span-size-002-ref.html">
+<style>
+.container, .has-height {
+  border: 1px solid;
+}
+
+.inline {
+  outline: 1px solid;
+}
+</style>
+<!-- Empty inline element in empty line has a height of zero. -->
+<div class="container"><ruby class="inline"></ruby></div><br>
+<!-- ... But not if the line has a meaningful height. -->
+<div class="container"><ruby class="inline"></ruby><ruby class="has-height"></ruby><ruby class="inline"></ruby></div><br>