Changeset 251642 in webkit

Timestamp:

Oct 27, 2019, 10:18:58 AM (7 years ago)

Author:

Alan Bujtas

Message:

[LFC][IFC] Do not expand runs with collapsed trailing whitespace
​https://bugs.webkit.org/show_bug.cgi?id=203468
<rdar://problem/56653689>

Reviewed by Antti Koivisto.

Runs are supposed to be a continuous chunk of content. Runs with trailing
collapsed whitespace can't accommodate additional trailing content.

• layout/inlineformatting/InlineLine.cpp:

(WebCore::Layout::Line::close):
(WebCore::Layout::Line::Run::isWhitespace const): Deleted.
(WebCore::Layout::Line::Run::canBeExtended const): Deleted.

• layout/inlineformatting/InlineLine.h:

(WebCore::Layout::Line::Run::expand):
(WebCore::Layout::Line::Run::isWhitespace const):
(WebCore::Layout::Line::Run::setIsCollapsed):
(WebCore::Layout::Line::Run::canBeExtended const):
(WebCore::Layout::Line::Run::setCollapsesToZeroAdvanceWidth):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• layout/inlineformatting/InlineLine.cpp (modified) (2 diffs)
• layout/inlineformatting/InlineLine.h (modified) (4 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-10-27  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC][IFC] Do not expand runs with collapsed trailing whitespace
+        https://bugs.webkit.org/show_bug.cgi?id=203468
+        <rdar://problem/56653689>
+
+        Reviewed by Antti Koivisto.
+
+        Runs are supposed to be a continuous chunk of content. Runs with trailing
+        collapsed whitespace can't accommodate additional trailing content.
+
+        * layout/inlineformatting/InlineLine.cpp:
+        (WebCore::Layout::Line::close):
+        (WebCore::Layout::Line::Run::isWhitespace const): Deleted.
+        (WebCore::Layout::Line::Run::canBeExtended const): Deleted.
+        * layout/inlineformatting/InlineLine.h:
+        (WebCore::Layout::Line::Run::expand):
+        (WebCore::Layout::Line::Run::isWhitespace const):
+        (WebCore::Layout::Line::Run::setIsCollapsed):
+        (WebCore::Layout::Line::Run::canBeExtended const):
+        (WebCore::Layout::Line::Run::setCollapsesToZeroAdvanceWidth):
+
 2019-10-27  Zalan Bujtas  <zalan@apple.com>
 

trunk/Source/WebCore/layout/inlineformatting/InlineLine.cpp

@@ -44 +44 @@
 }
 
-bool Line::Run::isWhitespace() const
-{
-    if (!isText())
-        return false;
-    return downcast<InlineTextItem>(m_inlineItem).isWhitespace();
-}
-
-bool Line::Run::canBeExtended() const
-{
-    if (!isText())
-        return false;
-    // Non-collapsed text runs can be merged into one continuous run.
-    if (isCollapsedToZeroAdvanceWidth())
-        return false;
-    return !isCollapsed();
-}
-
 Line::Line(const InlineFormattingContext& inlineFormattingContext, const InitialConstraints& initialConstraints, Optional<TextAlignMode> horizontalAlignment, SkipAlignment skipAlignment)
     : m_inlineFormattingContext(inlineFormattingContext)
@@ -139 +122 @@
         }
         auto& currentRun = m_runList[index];
-        if (!currentRun->isText() || &currentRun->layoutBox() != &previousRun->layoutBox()) {
-            // Do not merge runs from different boxes (<span>foo</span><span>bar</span>)
-            // or within the same layout box but with preserved \n
-            // (<span>text\n<span <- both the "text" and "\" belong to the same layout box)
+        // Do not merge runs from different boxes (<span>foo</span><span>bar</span>)
+        // or within the same layout box but with preserved \n
+        // (<span>text\n<span <- both the "text" and "\" belong to the same layout box)
+        auto canAppendToPreviousRun = currentRun->isText() && &currentRun->layoutBox() ==  &previousRun->layoutBox();
+        if (!canAppendToPreviousRun) {
             ++index;
             continue;

trunk/Source/WebCore/layout/inlineformatting/InlineLine.h

@@ -91 +91 @@
         void expand(const Run&);
 
-        void setIsCollapsed() { m_isCollapsed = true; }
+        void setIsCollapsed();
         void setCollapsesToZeroAdvanceWidth();
 
@@ -101 +101 @@
         bool m_isCollapsed { false };
         bool m_collapsedToZeroAdvanceWidth { false };
+        bool m_hasTrailingCollapsedContent { false };
     };
     using RunList = Vector<std::unique_ptr<Run>>;
@@ -156 +157 @@
     ASSERT(other.isText());
     ASSERT(!isCollapsedToZeroAdvanceWidth());
+    ASSERT(!m_hasTrailingCollapsedContent);
 
     auto& otherDisplayRun = other.displayRun();
     m_displayRun.expandHorizontally(otherDisplayRun.logicalWidth());
     m_displayRun.textContext()->expand(*otherDisplayRun.textContext());
+    m_hasTrailingCollapsedContent = other.isCollapsed();
+}
+
+inline bool Line::Run::isWhitespace() const
+{
+    return isText() && downcast<InlineTextItem>(m_inlineItem).isWhitespace();
+}
+
+inline void Line::Run::setIsCollapsed()
+{
+    ASSERT(isWhitespace());
+    m_isCollapsed = true;
+    m_hasTrailingCollapsedContent = true;
+}
+
+inline bool Line::Run::canBeExtended() const
+{
+    return isText() && !m_hasTrailingCollapsedContent;
 }
 
@@ -170 +190 @@
 inline void Line::Run::setCollapsesToZeroAdvanceWidth()
 {
+    setIsCollapsed();
     m_collapsedToZeroAdvanceWidth = true;
-    m_isCollapsed = true;
     m_displayRun.setLogicalWidth({ });
 }