Enable hyphens: auto and none in BreakingContext

third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h

Index: third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h
diff --git a/third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h b/third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h
index 7b5d2a0a98770914df9efc22daa3aa66bbd6a2a1..7e1eeb5ca803c765f862772fecab5f315f1a2d7e 100644
--- a/third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h
+++ b/third_party/WebKit/Source/core/layout/line/BreakingContextInlineHeaders.h
@@ -40,6 +40,7 @@
 #include "core/layout/line/TrailingObjects.h"
 #include "core/layout/line/WordMeasurement.h"
 #include "core/paint/PaintLayer.h"
+#include "platform/text/Hyphenation.h"
 #include "platform/text/TextBreakIterator.h"
 #include "wtf/Allocator.h"
 #include "wtf/Vector.h"
@@ -99,7 +100,7 @@ public:
     void handleReplaced();
     bool handleText(WordMeasurements&, bool& hyphenated);
     void prepareForNextCharacter(const LineLayoutText&, bool& prohibitBreakInside, bool previousCharacterIsSpace);
-    bool canBreakAtWhitespace(bool breakWords, WordMeasurement&, bool stoppedIgnoringSpaces, bool& hyphenated, float charWidth, float& hyphenWidth, bool betweenWords, bool midWordBreak, bool canBreakMidWord, bool previousCharacterIsSpace, float lastWidthMeasurement, const LineLayoutText&, const Font&, bool applyWordSpacing, float wordSpacing);
+    bool canBreakAtWhitespace(bool breakWords, WordMeasurement&, bool stoppedIgnoringSpaces, float charWidth, bool& hyphenated, bool disableSoftHyphen, float& hyphenWidth, bool betweenWords, bool midWordBreak, bool canBreakMidWord, bool previousCharacterIsSpace, float lastWidthMeasurement, const LineLayoutText&, const Font&, bool applyWordSpacing, float wordSpacing);
     bool trailingSpaceExceedsAvailableWidth(bool canBreakMidWord, const LineLayoutText&, WordMeasurement&, bool applyWordSpacing, bool wordSpacing, const Font&);
     WordMeasurement& calculateWordWidth(WordMeasurements&, LineLayoutText&, unsigned lastSpace, float& lastWidthMeasurement, float wordSpacingForWordMeasurement, const Font&, float wordTrailingSpaceWidth, UChar);
     void stopIgnoringSpaces(unsigned& lastSpace);
@@ -117,6 +118,7 @@ private:
     bool rewindToMidWordBreak(WordMeasurement&, int end, float width);
     bool rewindToFirstMidWordBreak(LineLayoutText, const ComputedStyle&, const Font&, bool breakAll, WordMeasurement&);
     bool rewindToMidWordBreak(LineLayoutText, const ComputedStyle&, const Font&, bool breakAll, WordMeasurement&);
+    bool hyphenate(LineLayoutText, const ComputedStyle&, const Font&, const Hyphenation&, float lastSpaceWordSpacing, WordMeasurement&);
 
     InlineBidiResolver& m_resolver;
 
@@ -560,8 +562,8 @@ ALWAYS_INLINE bool BreakingContext::rewindToMidWordBreak(
     wordMeasurement.endOffset = end;
     wordMeasurement.width = width;
 
-    m_current.moveTo(m_current.getLineLayoutItem(), end);
-    m_lineBreak.moveTo(m_current.getLineLayoutItem(), m_current.offset());
+    m_current.moveTo(m_current.getLineLayoutItem(), end, m_current.nextBreakablePosition());
+    m_lineBreak.moveTo(m_current.getLineLayoutItem(), end, m_current.nextBreakablePosition());
     return true;
 }
 
@@ -622,6 +624,46 @@ ALWAYS_INLINE bool BreakingContext::rewindToMidWordBreak(LineLayoutText text,
     return rewindToMidWordBreak(wordMeasurement, end, rect.width());
 }
 
+ALWAYS_INLINE bool BreakingContext::hyphenate(LineLayoutText text,
+    const ComputedStyle& style, const Font& font,
+    const Hyphenation& hyphenation, float lastSpaceWordSpacing,
+    WordMeasurement& wordMeasurement)
+{
+    const unsigned minimumPrefixLength = 2;
+    const unsigned minimumSuffixLength = 2;
+    unsigned start = wordMeasurement.startOffset;
+    unsigned len = wordMeasurement.endOffset - start;
+    if (len <= minimumSuffixLength)
+        return false;
+
+    float hyphenWidth = text.hyphenWidth(font, textDirectionFromUnicode(m_resolver.position().direction()));
+    float maxPrefixWidth = m_width.availableWidth() + LayoutUnit::epsilon()

[eae, 2016/05/16 16:43:26]

Do we need epsilon here? If we can ceil a floor to layout unit instead
LayoutUnit::fromFloatCeil that might allow us to not have to add epsilon.

[kojii, 2016/05/16 17:29:34]

When tests use ch/em that should exactly fit, this is needed. And also this is
aligned with LineWidth::fitsOnLine() adds epsilon. In break-all, without
epsilon, we can fit slightly less in existing tests.

But from the test in this CL, it doesn't fit when it's "3ch" (so the test has
"3.1ch"), and this is a new code path, so this can be removed if I adjust tests
to have slight buffer for other widths too. PS7 removes epsilon without
modifying tests, will add ".1ch" to tests if any fail.

[eae, 2016/05/16 17:32:38]

Thanks. We're trying to remove epsilon from LineWidth::fitsOnLine.

+        - m_width.currentWidth() - hyphenWidth - lastSpaceWordSpacing;
+
+    // If the maximum width available for the prefix before the hyphen is small, then it is very unlikely
+    // that an hyphenation opportunity exists, so do not bother to look for it.
+    const int minPrefixWidthNumerator = 5;

[eae, 2016/05/16 16:43:25]

Where did you get these numbers from?

[kojii, 2016/05/16 17:29:34]

From our removal patch (crrev.com/20526006). ToT WebKit has the same number.

[eae, 2016/05/16 17:32:38]

Ok, could you add a quick comment explaining the numbers?

+    const int minPrefixWidthDenominator = 4;
+    if (maxPrefixWidth <= font.getFontDescription().computedSize() * minPrefixWidthNumerator / minPrefixWidthDenominator)
+        return false;
+
+    TextRun run = constructTextRun(font, text, start, len, style);
+    run.setTabSize(!m_collapseWhiteSpace, style.getTabSize());
+    run.setXPos(m_width.currentWidth());
+    unsigned maxPrefixLength = font.offsetForPosition(run, maxPrefixWidth, false);
+    if (maxPrefixLength < minimumPrefixLength)
+        return false;
+
+    unsigned prefixLength = hyphenation.lastHyphenLocation(
+        text.text().createView(start, len),
+        std::min(maxPrefixLength, len - minimumSuffixLength) + 1);
+    if (!prefixLength || prefixLength < minimumPrefixLength)
+        return false;
+
+    FloatRect rect = font.selectionRectForText(run, FloatPoint(), 0, 0, prefixLength);

[eae, 2016/05/16 16:43:25]

Calling shaper.getCharacterRange instead of selection rect would be better as
that gives access to the actual character positions and doesn't do the snapping
or height adjustments.

[kojii, 2016/05/16 17:29:34]

Done.

[eae, 2016/05/16 17:32:38]

Thanks!`

+    return rewindToMidWordBreak(wordMeasurement, start + prefixLength, rect.width());
+}
+
 inline bool BreakingContext::handleText(WordMeasurements& wordMeasurements, bool& hyphenated)
 {
     if (!m_current.offset())
@@ -660,6 +702,9 @@ inline bool BreakingContext::handleText(WordMeasurements& wordMeasurements, bool
     // See: fast/css3-text/css3-word-break/word-break-all-wrap-with-floats.html
     float widthMeasurementAtLastBreakOpportunity = 0;
 
+    Hyphenation* hyphenation = style.getHyphens() == HyphensAuto
+        ? Hyphenation::get(font.getFontDescription().locale()) : nullptr;
+    bool disableSoftHyphen = style.getHyphens() == HyphensNone;
     float hyphenWidth = 0;
 
     if (layoutText.isSVGInlineText()) {
@@ -705,7 +750,7 @@ inline bool BreakingContext::handleText(WordMeasurements& wordMeasurements, bool
             m_width.setTrailingWhitespaceWidth(0);
         }
 
-        if (c == softHyphenCharacter && m_autoWrap && !hyphenWidth) {
+        if (c == softHyphenCharacter && m_autoWrap && !hyphenWidth && !disableSoftHyphen) {
             hyphenWidth = layoutText.hyphenWidth(font, textDirectionFromUnicode(m_resolver.position().direction()));
             m_width.addUncommittedWidth(hyphenWidth);
         }
@@ -726,7 +771,8 @@ inline bool BreakingContext::handleText(WordMeasurements& wordMeasurements, bool
 
         // Determine if we are in the whitespace between words.
         int nextBreakablePosition = m_current.nextBreakablePosition();
-        bool betweenWords = c == newlineCharacter || (m_currWS != PRE && !m_atStart && m_layoutTextInfo.m_lineBreakIterator.isBreakable(m_current.offset(), nextBreakablePosition, lineBreakType));
+        bool betweenWords = c == newlineCharacter || (m_currWS != PRE && !m_atStart && m_layoutTextInfo.m_lineBreakIterator.isBreakable(m_current.offset(), nextBreakablePosition, lineBreakType)
+            && (!disableSoftHyphen || m_current.previousInSameNode() != softHyphenCharacter));
         m_current.setNextBreakablePosition(nextBreakablePosition);
 
         // If we're in the middle of a word or at the start of a new one and can't break there, then continue to the next character.
@@ -788,18 +834,31 @@ inline bool BreakingContext::handleText(WordMeasurements& wordMeasurements, bool
             m_width.fitBelowFloats(m_lineInfo.isFirstLine());
 
         midWordBreak = false;
-        if (canBreakMidWord && !m_width.fitsOnLine()) {
-            m_width.addUncommittedWidth(-wordMeasurement.width);
-            if (rewindToMidWordBreak(layoutText, style, font, breakAll, wordMeasurement)) {
-                lastWidthMeasurement = wordMeasurement.width + lastSpaceWordSpacing;
-                midWordBreak = true;
+        if (!m_width.fitsOnLine()) {
+            if (canBreakMidWord) {
+                m_width.addUncommittedWidth(-wordMeasurement.width);
+                if (rewindToMidWordBreak(layoutText, style, font, breakAll, wordMeasurement)) {
+                    lastWidthMeasurement = wordMeasurement.width + lastSpaceWordSpacing;
+                    midWordBreak = true;
+                }
+                m_width.addUncommittedWidth(wordMeasurement.width);
+            } else if (hyphenation) {
+                m_width.addUncommittedWidth(-wordMeasurement.width);
+                DCHECK(lastSpace == static_cast<unsigned>(wordMeasurement.startOffset));
+                DCHECK(m_current.offset() == static_cast<unsigned>(wordMeasurement.endOffset));
+                if (hyphenate(layoutText, style, font, *hyphenation, lastSpaceWordSpacing, wordMeasurement)) {
+                    m_width.addUncommittedWidth(wordMeasurement.width);
+                    hyphenated = true;
+                    m_atEnd = true;
+                    return false;
+                }
+                m_width.addUncommittedWidth(wordMeasurement.width);
             }
-            m_width.addUncommittedWidth(wordMeasurement.width);
         }
 
         // If there is a soft-break available at this whitespace position then take it.
         applyWordSpacing = wordSpacing && m_currentCharacterIsSpace;
-        if (canBreakAtWhitespace(breakWords, wordMeasurement, stoppedIgnoringSpaces, hyphenated, charWidth, hyphenWidth, betweenWords, midWordBreak, canBreakMidWord, previousCharacterIsSpace, lastWidthMeasurement, layoutText, font, applyWordSpacing, wordSpacing))
+        if (canBreakAtWhitespace(breakWords, wordMeasurement, stoppedIgnoringSpaces, charWidth, hyphenated, disableSoftHyphen, hyphenWidth, betweenWords, midWordBreak, canBreakMidWord, previousCharacterIsSpace, lastWidthMeasurement, layoutText, font, applyWordSpacing, wordSpacing))
             return false;
 
         // If there is a hard-break available at this whitespace position then take it.
@@ -882,10 +941,23 @@ inline bool BreakingContext::handleText(WordMeasurements& wordMeasurements, bool
     if (midWordBreak) {
         m_width.commit();
         m_atEnd = true;
-    } else if (!m_width.fitsOnLine() && !hyphenated
-        && m_lineBreak.previousInSameNode() == softHyphenCharacter) {
-        hyphenated = true;
-        m_atEnd = true;
+    } else if (!m_width.fitsOnLine()) {
+        if (hyphenation && (m_nextObject || m_lineInfo.isEmpty())) {
+            m_width.addUncommittedWidth(-wordMeasurement.width);
+            DCHECK(lastSpace == static_cast<unsigned>(wordMeasurement.startOffset));
+            DCHECK(m_current.offset() == static_cast<unsigned>(wordMeasurement.endOffset));
+            if (hyphenate(layoutText, style, font, *hyphenation, lastSpaceWordSpacing, wordMeasurement)) {
+                hyphenated = true;
+                m_atEnd = true;
+            }
+            m_width.addUncommittedWidth(wordMeasurement.width);
+        }
+        if (!hyphenated
+            && m_lineBreak.previousInSameNode() == softHyphenCharacter
+            && !disableSoftHyphen) {
+            hyphenated = true;
+            m_atEnd = true;
+        }
     }
     return false;
 }
@@ -961,7 +1033,7 @@ inline bool BreakingContext::trailingSpaceExceedsAvailableWidth(bool canBreakMid
     return false;
 }
 
-inline bool BreakingContext::canBreakAtWhitespace(bool breakWords, WordMeasurement& wordMeasurement, bool stoppedIgnoringSpaces, bool& hyphenated, float charWidth, float& hyphenWidth, bool betweenWords, bool midWordBreak, bool canBreakMidWord, bool previousCharacterIsSpace, float lastWidthMeasurement, const LineLayoutText& layoutText, const Font& font, bool applyWordSpacing, float wordSpacing)
+inline bool BreakingContext::canBreakAtWhitespace(bool breakWords, WordMeasurement& wordMeasurement, bool stoppedIgnoringSpaces, float charWidth, bool& hyphenated, bool disableSoftHyphen, float& hyphenWidth, bool betweenWords, bool midWordBreak, bool canBreakMidWord, bool previousCharacterIsSpace, float lastWidthMeasurement, const LineLayoutText& layoutText, const Font& font, bool applyWordSpacing, float wordSpacing)
 {
     if (!m_autoWrap && !breakWords)
         return false;
@@ -978,7 +1050,7 @@ inline bool BreakingContext::canBreakAtWhitespace(bool breakWords, WordMeasureme
             m_lineInfo.setPreviousLineBrokeCleanly(true);
             wordMeasurement.endOffset = m_lineBreak.offset();
         }
-        if (m_lineBreak.getLineLayoutItem() && m_lineBreak.offset() && m_lineBreak.getLineLayoutItem().isText() && LineLayoutText(m_lineBreak.getLineLayoutItem()).textLength() && LineLayoutText(m_lineBreak.getLineLayoutItem()).characterAt(m_lineBreak.offset() - 1) == softHyphenCharacter)
+        if (m_lineBreak.getLineLayoutItem() && m_lineBreak.offset() && m_lineBreak.getLineLayoutItem().isText() && LineLayoutText(m_lineBreak.getLineLayoutItem()).textLength() && LineLayoutText(m_lineBreak.getLineLayoutItem()).characterAt(m_lineBreak.offset() - 1) == softHyphenCharacter && !disableSoftHyphen)
             hyphenated = true;
         if (m_lineBreak.offset() && m_lineBreak.offset() != (unsigned)wordMeasurement.endOffset && !wordMeasurement.width) {
             if (charWidth) {