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Diffstat (limited to 'Source/WebCore/rendering/line/BreakingContext.h')
| -rw-r--r-- | Source/WebCore/rendering/line/BreakingContext.h | 1367 |
1 files changed, 1367 insertions, 0 deletions
diff --git a/Source/WebCore/rendering/line/BreakingContext.h b/Source/WebCore/rendering/line/BreakingContext.h new file mode 100644 index 000000000..d94d17a65 --- /dev/null +++ b/Source/WebCore/rendering/line/BreakingContext.h @@ -0,0 +1,1367 @@ +/* + * Copyright (C) 2000 Lars Knoll (knoll@kde.org) + * Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All right reserved. + * Copyright (C) 2010 Google Inc. All rights reserved. + * Copyright (C) 2013 ChangSeok Oh <shivamidow@gmail.com> + * Copyright (C) 2013 Adobe Systems Inc. All right reserved. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public License + * along with this library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + * Boston, MA 02110-1301, USA. + * + */ + +#pragma once + +#include "BreakLines.h" +#include "Hyphenation.h" +#include "LineBreaker.h" +#include "LineInfo.h" +#include "LineLayoutState.h" +#include "LineWidth.h" +#include "RenderCombineText.h" +#include "RenderCounter.h" +#include "RenderInline.h" +#include "RenderLineBreak.h" +#include "RenderListMarker.h" +#include "RenderRubyRun.h" +#include "RenderSVGInlineText.h" +#include "TrailingObjects.h" +#include <wtf/Optional.h> +#include <wtf/text/StringView.h> +#include <wtf/unicode/CharacterNames.h> + +namespace WebCore { + +// We don't let our line box tree for a single line get any deeper than this. +const unsigned cMaxLineDepth = 200; + +struct WordMeasurement { + WordMeasurement() + : renderer(0) + , width(0) + , startOffset(0) + , endOffset(0) + { + } + + RenderText* renderer; + float width; + unsigned startOffset; + unsigned endOffset; + HashSet<const Font*> fallbackFonts; +}; + +struct WordTrailingSpace { + WordTrailingSpace(const RenderStyle& style, TextLayout* textLayout = nullptr) + : m_style(style) + , m_textLayout(textLayout) + { + } + + std::optional<float> width(HashSet<const Font*>& fallbackFonts) + { + if (m_state == WordTrailingSpaceState::Computed) + return m_width; + + const FontCascade& font = m_style.fontCascade(); + if (font.enableKerning() && !m_textLayout) + m_width = font.width(RenderBlock::constructTextRun(&space, 1, m_style), &fallbackFonts) + font.wordSpacing(); + m_state = WordTrailingSpaceState::Computed; + return m_width; + } + +private: + enum class WordTrailingSpaceState { Uninitialized, Computed }; + WordTrailingSpaceState m_state { WordTrailingSpaceState::Uninitialized }; + std::optional<float> m_width; + const RenderStyle& m_style; + TextLayout* m_textLayout { nullptr }; +}; + +class BreakingContext { +public: + BreakingContext(LineBreaker& lineBreaker, InlineBidiResolver& resolver, LineInfo& inLineInfo, LineLayoutState& layoutState, LineWidth& lineWidth, RenderTextInfo& inRenderTextInfo, FloatingObject* inLastFloatFromPreviousLine, bool appliedStartWidth, RenderBlockFlow& block) + : m_lineBreaker(lineBreaker) + , m_resolver(resolver) + , m_current(resolver.position()) +#if ENABLE(CSS_TRAILING_WORD) + , m_lineBreakHistory(InlineIterator(resolver.position()), block.style().trailingWord() == TrailingWord::PartiallyBalanced ? 5 : 1) +#else + , m_lineBreakHistory(InlineIterator(resolver.position()), 1) +#endif + , m_block(block) + , m_lastObject(m_current.renderer()) + , m_nextObject(nullptr) + , m_currentStyle(nullptr) + , m_blockStyle(block.style()) + , m_lineInfo(inLineInfo) + , m_renderTextInfo(inRenderTextInfo) + , m_lastFloatFromPreviousLine(inLastFloatFromPreviousLine) + , m_width(lineWidth) + , m_lineLayoutState(layoutState) + , m_currWS(NORMAL) + , m_lastWS(NORMAL) + , m_preservesNewline(false) + , m_atStart(true) + , m_ignoringSpaces(false) + , m_currentCharacterIsSpace(false) + , m_currentCharacterIsWS(false) + , m_appliedStartWidth(appliedStartWidth) + , m_includeEndWidth(true) + , m_autoWrap(false) + , m_autoWrapWasEverTrueOnLine(false) + , m_floatsFitOnLine(true) + , m_collapseWhiteSpace(false) + , m_startingNewParagraph(m_lineInfo.previousLineBrokeCleanly()) + , m_allowImagesToBreak(!block.document().inQuirksMode() || !block.isTableCell() || !m_blockStyle.logicalWidth().isIntrinsicOrAuto()) + , m_atEnd(false) + , m_hadUncommittedWidthBeforeCurrent(false) + , m_lineWhitespaceCollapsingState(resolver.whitespaceCollapsingState()) + { + m_lineInfo.setPreviousLineBrokeCleanly(false); + } + + RenderObject* currentObject() { return m_current.renderer(); } + InlineIterator lineBreak() { return m_lineBreakHistory.current(); } + LineWidth& lineWidth() { return m_width; } + bool atEnd() { return m_atEnd; } + + bool fitsOnLineOrHangsAtEnd() const { return m_width.fitsOnLine() || m_hangsAtEnd; } + + void initializeForCurrentObject(); + + void increment(); + + void handleBR(EClear&); + void handleOutOfFlowPositioned(Vector<RenderBox*>& positionedObjects); + void handleFloat(); + void handleEmptyInline(); + void handleReplaced(); + bool handleText(WordMeasurements&, bool& hyphenated, unsigned& consecutiveHyphenatedLines); + bool canBreakAtThisPosition(); + void commitAndUpdateLineBreakIfNeeded(); + InlineIterator handleEndOfLine(); +#if ENABLE(CSS_TRAILING_WORD) + InlineIterator optimalLineBreakLocationForTrailingWord(); +#endif + + float computeAdditionalBetweenWordsWidth(RenderText&, TextLayout*, UChar, WordTrailingSpace&, HashSet<const Font*>& fallbackFonts, WordMeasurements&, const FontCascade&, bool isFixedPitch, unsigned lastSpace, float lastSpaceWordSpacing, float wordSpacingForWordMeasurement, unsigned offset); + + void clearLineBreakIfFitsOnLine(bool ignoringTrailingSpace = false) + { + if (m_width.fitsOnLine(ignoringTrailingSpace) || m_lastWS == NOWRAP || m_hangsAtEnd) + m_lineBreakHistory.clear(); + m_hangsAtEnd = false; + } + + void commitLineBreakClear() + { + m_width.commit(); + m_lineBreakHistory.clear(); + m_hangsAtEnd = false; + } + + void commitLineBreakAtCurrentWidth(RenderObject& object, unsigned offset = 0, std::optional<unsigned> nextBreak = std::optional<unsigned>()) + { + m_width.commit(); + m_lineBreakHistory.moveTo(object, offset, nextBreak); + m_hangsAtEnd = false; + } + +private: + // This class keeps a sliding window of the past n locations for an InlineIterator. + class InlineIteratorHistory : private Vector<InlineIterator, 1> { + public: + InlineIteratorHistory() = delete; + InlineIteratorHistory(const InlineIterator& initial, size_t capacity) + : m_capacity(capacity) + { + ASSERT(capacity > 0); + this->append(initial); + } + + void push(std::function<void(InlineIterator& modifyMe)> updater) + { + ASSERT(!this->isEmpty()); + if (m_capacity != 1) + this->insert(0, InlineIterator(this->at(0))); + updater(this->at(0)); + if (m_capacity != 1) + this->resize(m_capacity); + } + + void update(std::function<void(InlineIterator& modifyMe)> updater) + { + ASSERT(!this->isEmpty()); + updater(this->at(0)); + } + + RenderObject* renderer() const { return this->at(0).renderer(); } + unsigned offset() const { return this->at(0).offset(); } + std::optional<unsigned> nextBreakablePosition() const { return this->at(0).nextBreakablePosition(); } + bool atTextParagraphSeparator() const { return this->at(0).atTextParagraphSeparator(); } + UChar previousInSameNode() const { return this->at(0).previousInSameNode(); } + const InlineIterator& get(size_t i) const { return this->at(i); }; + const InlineIterator& current() const { return get(0); } + size_t historyLength() const { return this->size(); } + + void moveTo(RenderObject& object, unsigned offset, std::optional<unsigned> nextBreak = std::nullopt) + { + push([&](InlineIterator& modifyMe) { + modifyMe.moveTo(object, offset, nextBreak); + }); + } + + void increment() + { + update([](InlineIterator& modifyMe) { + modifyMe.increment(); + }); + } + + void clear() + { + push([](InlineIterator& modifyMe) { + modifyMe.clear(); + }); + } + + private: + const size_t m_capacity; + }; + + LineBreaker& m_lineBreaker; + InlineBidiResolver& m_resolver; + + InlineIterator m_current; + InlineIteratorHistory m_lineBreakHistory; + InlineIterator m_startOfIgnoredSpaces; + + RenderBlockFlow& m_block; + RenderObject* m_lastObject; + RenderObject* m_nextObject; + + const RenderStyle* m_currentStyle; + + // Firefox and Opera will allow a table cell to grow to fit an image inside it under + // very specific circumstances (in order to match common WinIE renderings). + // Not supporting the quirk has caused us to mis-render some real sites. (See Bugzilla 10517.) + const RenderStyle& m_blockStyle; + + LineInfo& m_lineInfo; + + RenderTextInfo& m_renderTextInfo; + + FloatingObject* m_lastFloatFromPreviousLine; + + LineWidth m_width; + + LineLayoutState& m_lineLayoutState; + + EWhiteSpace m_currWS; + EWhiteSpace m_lastWS; + + bool m_preservesNewline; + bool m_atStart; + + // This variable is used only if whitespace isn't set to PRE, and it tells us whether + // or not we are currently ignoring whitespace. + bool m_ignoringSpaces; + + // This variable tracks whether the very last character we saw was a space. We use + // this to detect when we encounter a second space so we know we have to terminate + // a run. + bool m_currentCharacterIsSpace; + bool m_currentCharacterIsWS; + bool m_appliedStartWidth; + bool m_includeEndWidth; + bool m_autoWrap; + bool m_autoWrapWasEverTrueOnLine; + bool m_floatsFitOnLine; + bool m_collapseWhiteSpace; + bool m_startingNewParagraph; + bool m_allowImagesToBreak; + bool m_atEnd; + bool m_hadUncommittedWidthBeforeCurrent; + + bool m_hangsAtEnd { false }; + + LineWhitespaceCollapsingState& m_lineWhitespaceCollapsingState; + + TrailingObjects m_trailingObjects; +}; + +inline void BreakingContext::initializeForCurrentObject() +{ + m_hadUncommittedWidthBeforeCurrent = !!m_width.uncommittedWidth(); + + m_currentStyle = &m_current.renderer()->style(); // FIXME: Should this be &lineStyle(*m_current.renderer(), m_lineInfo); ? + + ASSERT(m_currentStyle); + + m_nextObject = bidiNextSkippingEmptyInlines(m_block, m_current.renderer()); + if (m_nextObject && m_nextObject->parent() && !m_nextObject->parent()->isDescendantOf(m_current.renderer()->parent())) + m_includeEndWidth = true; + + m_currWS = m_current.renderer()->isReplaced() ? m_current.renderer()->parent()->style().whiteSpace() : m_currentStyle->whiteSpace(); + m_lastWS = m_lastObject->isReplaced() ? m_lastObject->parent()->style().whiteSpace() : m_lastObject->style().whiteSpace(); + + m_autoWrap = RenderStyle::autoWrap(m_currWS); + m_autoWrapWasEverTrueOnLine = m_autoWrapWasEverTrueOnLine || m_autoWrap; + + m_preservesNewline = m_current.renderer()->isSVGInlineText() ? false : RenderStyle::preserveNewline(m_currWS); + + m_collapseWhiteSpace = RenderStyle::collapseWhiteSpace(m_currWS); +} + +inline void BreakingContext::increment() +{ + // Clear out our character space bool, since inline <pre>s don't collapse whitespace + // with adjacent inline normal/nowrap spans. + if (!m_collapseWhiteSpace) + m_currentCharacterIsSpace = false; + + if (m_nextObject) + m_current.moveToStartOf(*m_nextObject); + else + m_current.clear(); + m_atStart = false; +} + +inline void BreakingContext::handleBR(EClear& clear) +{ + if (fitsOnLineOrHangsAtEnd()) { + RenderObject& br = *m_current.renderer(); + m_lineBreakHistory.push([&](InlineIterator& modifyMe) { + modifyMe.moveToStartOf(br); + modifyMe.increment(); + }); + + // A <br> always breaks a line, so don't let the line be collapsed + // away. Also, the space at the end of a line with a <br> does not + // get collapsed away. It only does this if the previous line broke + // cleanly. Otherwise the <br> has no effect on whether the line is + // empty or not. + if (m_startingNewParagraph) + m_lineInfo.setEmpty(false, &m_block, &m_width); + m_trailingObjects.clear(); + m_lineInfo.setPreviousLineBrokeCleanly(true); + + // A <br> with clearance always needs a linebox in case the lines below it get dirtied later and + // need to check for floats to clear - so if we're ignoring spaces, stop ignoring them and add a + // run for this object. + if (m_ignoringSpaces && m_currentStyle->clear() != CNONE) + m_lineWhitespaceCollapsingState.ensureLineBoxInsideIgnoredSpaces(br); + // If we were preceded by collapsing space and are in a right-aligned container we need to ensure the space gets + // collapsed away so that it doesn't push the text out from the container's right-hand edge. + // FIXME: Do this regardless of the container's alignment - will require rebaselining a lot of test results. + else if (m_ignoringSpaces && (m_blockStyle.textAlign() == RIGHT || m_blockStyle.textAlign() == WEBKIT_RIGHT)) + m_lineWhitespaceCollapsingState.stopIgnoringSpaces(InlineIterator(0, m_current.renderer(), m_current.offset())); + + if (!m_lineInfo.isEmpty()) + clear = m_currentStyle->clear(); + } + m_atEnd = true; +} + +inline LayoutUnit borderPaddingMarginStart(const RenderInline& child) +{ + return child.marginStart() + child.paddingStart() + child.borderStart(); +} + +inline LayoutUnit borderPaddingMarginEnd(const RenderInline& child) +{ + return child.marginEnd() + child.paddingEnd() + child.borderEnd(); +} + +inline bool shouldAddBorderPaddingMargin(RenderObject* child) +{ + if (!child) + return true; + // When deciding whether we're at the edge of an inline, adjacent collapsed whitespace is the same as no sibling at all. + if (is<RenderText>(*child) && !downcast<RenderText>(*child).textLength()) + return true; +#if ENABLE(CSS_BOX_DECORATION_BREAK) + if (is<RenderLineBreak>(*child) && child->parent()->style().boxDecorationBreak() == DCLONE) + return true; +#endif + return false; +} + +inline RenderObject* previousInFlowSibling(RenderObject* child) +{ + do { + child = child->previousSibling(); + } while (child && child->isOutOfFlowPositioned()); + return child; +} + +inline LayoutUnit inlineLogicalWidth(RenderObject* child, bool checkStartEdge = true, bool checkEndEdge = true) +{ + unsigned lineDepth = 1; + LayoutUnit extraWidth = 0; + RenderElement* parent = child->parent(); + while (is<RenderInline>(*parent) && lineDepth++ < cMaxLineDepth) { + const auto& parentAsRenderInline = downcast<RenderInline>(*parent); + if (!isEmptyInline(parentAsRenderInline)) { + checkStartEdge = checkStartEdge && shouldAddBorderPaddingMargin(previousInFlowSibling(child)); + if (checkStartEdge) + extraWidth += borderPaddingMarginStart(parentAsRenderInline); + checkEndEdge = checkEndEdge && shouldAddBorderPaddingMargin(child->nextSibling()); + if (checkEndEdge) + extraWidth += borderPaddingMarginEnd(parentAsRenderInline); + if (!checkStartEdge && !checkEndEdge) + return extraWidth; + } + child = parent; + parent = child->parent(); + } + return extraWidth; +} + +inline void BreakingContext::handleOutOfFlowPositioned(Vector<RenderBox*>& positionedObjects) +{ + // If our original display wasn't an inline type, then we can determine our static inline position now. + auto& box = downcast<RenderBox>(*m_current.renderer()); + bool isInlineType = box.style().isOriginalDisplayInlineType(); + if (!isInlineType) + m_block.setStaticInlinePositionForChild(box, m_block.logicalHeight(), m_block.startOffsetForContent(m_block.logicalHeight())); + else { + // If our original display was an INLINE type, then we can determine our static y position now. + box.layer()->setStaticBlockPosition(m_block.logicalHeight()); + } + + // If we're ignoring spaces, we have to stop and include this object and + // then start ignoring spaces again. + if (isInlineType || box.container()->isRenderInline()) { + if (m_ignoringSpaces) + m_lineWhitespaceCollapsingState.ensureLineBoxInsideIgnoredSpaces(box); + m_trailingObjects.appendBoxIfNeeded(box); + } else + positionedObjects.append(&box); + + m_width.addUncommittedWidth(inlineLogicalWidth(&box)); + // Reset prior line break context characters. + m_renderTextInfo.lineBreakIterator.resetPriorContext(); +} + +inline void BreakingContext::handleFloat() +{ + auto& floatBox = downcast<RenderBox>(*m_current.renderer()); + const auto& floatingObject = *m_lineBreaker.insertFloatingObject(floatBox); + // check if it fits in the current line. + // If it does, position it now, otherwise, position + // it after moving to next line (in clearFloats() func) + if (m_floatsFitOnLine && m_width.fitsOnLineExcludingTrailingWhitespace(m_block.logicalWidthForFloat(floatingObject))) { + m_lineBreaker.positionNewFloatOnLine(floatingObject, m_lastFloatFromPreviousLine, m_lineInfo, m_width); + if (m_lineBreakHistory.renderer() == m_current.renderer()) { + ASSERT(!m_lineBreakHistory.offset()); + m_lineBreakHistory.increment(); + } + } else + m_floatsFitOnLine = false; + // Update prior line break context characters, using U+FFFD (OBJECT REPLACEMENT CHARACTER) for floating element. + m_renderTextInfo.lineBreakIterator.updatePriorContext(replacementCharacter); +} + +// This is currently just used for list markers and inline flows that have line boxes. Neither should +// have an effect on whitespace at the start of the line. +inline bool shouldSkipWhitespaceAfterStartObject(RenderBlockFlow& block, RenderObject* o, LineWhitespaceCollapsingState& lineWhitespaceCollapsingState) +{ + RenderObject* next = bidiNextSkippingEmptyInlines(block, o); + while (next && next->isFloatingOrOutOfFlowPositioned()) + next = bidiNextSkippingEmptyInlines(block, next); + + if (is<RenderText>(next) && downcast<RenderText>(*next).textLength() > 0) { + RenderText& nextText = downcast<RenderText>(*next); + UChar nextChar = nextText.characterAt(0); + if (nextText.style().isCollapsibleWhiteSpace(nextChar)) { + lineWhitespaceCollapsingState.startIgnoringSpaces(InlineIterator(nullptr, o, 0)); + return true; + } + } + + return false; +} + +inline void BreakingContext::handleEmptyInline() +{ + RenderInline& flowBox = downcast<RenderInline>(*m_current.renderer()); + + // This should only end up being called on empty inlines + ASSERT(isEmptyInline(flowBox)); + + // Now that some inline flows have line boxes, if we are already ignoring spaces, we need + // to make sure that we stop to include this object and then start ignoring spaces again. + // If this object is at the start of the line, we need to behave like list markers and + // start ignoring spaces. + bool requiresLineBox = alwaysRequiresLineBox(flowBox); + if (requiresLineBox || requiresLineBoxForContent(flowBox, m_lineInfo)) { + // An empty inline that only has line-height, vertical-align or font-metrics will only get a + // line box to affect the height of the line if the rest of the line is not empty. + if (requiresLineBox) + m_lineInfo.setEmpty(false, &m_block, &m_width); + if (m_ignoringSpaces) { + m_trailingObjects.clear(); + m_lineWhitespaceCollapsingState.ensureLineBoxInsideIgnoredSpaces(*m_current.renderer()); + } else if (m_blockStyle.collapseWhiteSpace() && m_resolver.position().renderer() == m_current.renderer() + && shouldSkipWhitespaceAfterStartObject(m_block, m_current.renderer(), m_lineWhitespaceCollapsingState)) { + // Like with list markers, we start ignoring spaces to make sure that any + // additional spaces we see will be discarded. + m_currentCharacterIsSpace = true; + m_currentCharacterIsWS = true; + m_ignoringSpaces = true; + } else + m_trailingObjects.appendBoxIfNeeded(flowBox); + } + + float inlineWidth = inlineLogicalWidth(m_current.renderer()) + borderPaddingMarginStart(flowBox) + borderPaddingMarginEnd(flowBox); + m_width.addUncommittedWidth(inlineWidth); + if (m_hangsAtEnd && inlineWidth) + m_hangsAtEnd = false; +} + +inline void BreakingContext::handleReplaced() +{ + auto& replacedBox = downcast<RenderBox>(*m_current.renderer()); + + if (m_atStart) + m_width.updateAvailableWidth(replacedBox.logicalHeight()); + + // Break on replaced elements if either has normal white-space. + if (((m_autoWrap || RenderStyle::autoWrap(m_lastWS)) && (!m_current.renderer()->isImage() || m_allowImagesToBreak) + && (!m_current.renderer()->isRubyRun() || downcast<RenderRubyRun>(m_current.renderer())->canBreakBefore(m_renderTextInfo.lineBreakIterator))) || replacedBox.isAnonymousInlineBlock()) { + if (auto* renderer = m_current.renderer()) + commitLineBreakAtCurrentWidth(*renderer); + else + commitLineBreakClear(); + if (m_width.committedWidth() && replacedBox.isAnonymousInlineBlock()) { + // Always force a break before an anonymous inline block if there is content on the line + // already. + m_atEnd = true; + return; + } + } else + m_hangsAtEnd = false; + + if (replacedBox.isAnonymousInlineBlock()) + m_block.layoutBlockChild(replacedBox, m_lineLayoutState.marginInfo(), + m_lineLayoutState.prevFloatBottomFromAnonymousInlineBlock(), m_lineLayoutState.maxFloatBottomFromAnonymousInlineBlock()); + + if (m_ignoringSpaces) + m_lineWhitespaceCollapsingState.stopIgnoringSpaces(InlineIterator(0, m_current.renderer(), 0)); + + m_lineInfo.setEmpty(false, &m_block, &m_width); + m_ignoringSpaces = false; + m_currentCharacterIsSpace = false; + m_currentCharacterIsWS = false; + m_trailingObjects.clear(); + + // Optimize for a common case. If we can't find whitespace after the list + // item, then this is all moot. + LayoutUnit replacedLogicalWidth = m_block.logicalWidthForChild(replacedBox) + m_block.marginStartForChild(replacedBox) + m_block.marginEndForChild(replacedBox) + inlineLogicalWidth(m_current.renderer()); + if (is<RenderListMarker>(*m_current.renderer())) { + if (m_blockStyle.collapseWhiteSpace() && shouldSkipWhitespaceAfterStartObject(m_block, m_current.renderer(), m_lineWhitespaceCollapsingState)) { + // Like with inline flows, we start ignoring spaces to make sure that any + // additional spaces we see will be discarded. + m_currentCharacterIsSpace = true; + m_currentCharacterIsWS = false; + m_ignoringSpaces = true; + } + if (downcast<RenderListMarker>(*m_current.renderer()).isInside()) + m_width.addUncommittedReplacedWidth(replacedLogicalWidth); + } else + m_width.addUncommittedReplacedWidth(replacedLogicalWidth); + if (is<RenderRubyRun>(*m_current.renderer())) { + m_width.applyOverhang(downcast<RenderRubyRun>(m_current.renderer()), m_lastObject, m_nextObject); + downcast<RenderRubyRun>(m_current.renderer())->updatePriorContextFromCachedBreakIterator(m_renderTextInfo.lineBreakIterator); + } else { + // Update prior line break context characters, using U+FFFD (OBJECT REPLACEMENT CHARACTER) for replaced element. + m_renderTextInfo.lineBreakIterator.updatePriorContext(replacementCharacter); + } + + if (replacedBox.isAnonymousInlineBlock()) { + m_atEnd = true; + m_lineInfo.setPreviousLineBrokeCleanly(true); + } +} + +inline float firstPositiveWidth(const WordMeasurements& wordMeasurements) +{ + for (size_t i = 0; i < wordMeasurements.size(); ++i) { + if (wordMeasurements[i].width > 0) + return wordMeasurements[i].width; + } + return 0; +} + +inline bool iteratorIsBeyondEndOfRenderCombineText(const InlineIterator& iter, RenderCombineText& renderer) +{ + return iter.renderer() == &renderer && iter.offset() >= renderer.textLength(); +} + +inline void nextCharacter(UChar& currentCharacter, UChar& lastCharacter, UChar& secondToLastCharacter) +{ + secondToLastCharacter = lastCharacter; + lastCharacter = currentCharacter; +} + +// FIXME: Don't let counters mark themselves as needing pref width recalcs during layout +// so we don't need this hack. +inline void updateCounterIfNeeded(RenderText& renderText) +{ + if (!renderText.preferredLogicalWidthsDirty() || !is<RenderCounter>(renderText)) + return; + downcast<RenderCounter>(renderText).updateCounter(); +} + +inline float measureHyphenWidth(RenderText& renderer, const FontCascade& font, HashSet<const Font*>* fallbackFonts = 0) +{ + const RenderStyle& style = renderer.style(); + return font.width(RenderBlock::constructTextRun(style.hyphenString().string(), style), fallbackFonts); +} + +ALWAYS_INLINE float textWidth(RenderText& text, unsigned from, unsigned len, const FontCascade& font, float xPos, bool isFixedPitch, bool collapseWhiteSpace, HashSet<const Font*>& fallbackFonts, TextLayout* layout = nullptr) +{ + const RenderStyle& style = text.style(); + + GlyphOverflow glyphOverflow; + if (isFixedPitch || (!from && len == text.textLength()) || style.hasTextCombine()) + return text.width(from, len, font, xPos, &fallbackFonts, &glyphOverflow); + + if (layout) + return FontCascade::width(*layout, from, len, &fallbackFonts); + + TextRun run = RenderBlock::constructTextRun(text, from, len, style); + run.setCharactersLength(text.textLength() - from); + ASSERT(run.charactersLength() >= run.length()); + + run.setCharacterScanForCodePath(!text.canUseSimpleFontCodePath()); + run.setTabSize(!collapseWhiteSpace, style.tabSize()); + run.setXPos(xPos); + return font.width(run, &fallbackFonts, &glyphOverflow); +} + +// Adding a pair of whitespace collapsing transitions before a character will split it out into a new line box. +inline void ensureCharacterGetsLineBox(LineWhitespaceCollapsingState& lineWhitespaceCollapsingState, InlineIterator& textParagraphSeparator) +{ + InlineIterator transition(0, textParagraphSeparator.renderer(), textParagraphSeparator.offset()); + lineWhitespaceCollapsingState.startIgnoringSpaces(InlineIterator(0, textParagraphSeparator.renderer(), textParagraphSeparator.offset() - 1)); + lineWhitespaceCollapsingState.stopIgnoringSpaces(InlineIterator(0, textParagraphSeparator.renderer(), textParagraphSeparator.offset())); +} + +inline void tryHyphenating(RenderText& text, const FontCascade& font, const AtomicString& localeIdentifier, unsigned consecutiveHyphenatedLines, int consecutiveHyphenatedLinesLimit, int minimumPrefixLimit, int minimumSuffixLimit, unsigned lastSpace, unsigned pos, float xPos, float availableWidth, bool isFixedPitch, bool collapseWhiteSpace, int lastSpaceWordSpacing, InlineIterator& lineBreak, std::optional<unsigned> nextBreakable, bool& hyphenated) +{ + // Map 'hyphenate-limit-{before,after}: auto;' to 2. + unsigned minimumPrefixLength; + unsigned minimumSuffixLength; + + if (minimumPrefixLimit < 0) + minimumPrefixLength = 2; + else + minimumPrefixLength = static_cast<unsigned>(minimumPrefixLimit); + + if (minimumSuffixLimit < 0) + minimumSuffixLength = 2; + else + minimumSuffixLength = static_cast<unsigned>(minimumSuffixLimit); + + if (pos - lastSpace <= minimumSuffixLength) + return; + + if (consecutiveHyphenatedLinesLimit >= 0 && consecutiveHyphenatedLines >= static_cast<unsigned>(consecutiveHyphenatedLinesLimit)) + return; + + float hyphenWidth = measureHyphenWidth(text, font); + + float maxPrefixWidth = availableWidth - xPos - hyphenWidth - lastSpaceWordSpacing; + if (!enoughWidthForHyphenation(maxPrefixWidth, font.pixelSize())) + return; + + const RenderStyle& style = text.style(); + TextRun run = RenderBlock::constructTextRun(text, lastSpace, pos - lastSpace, style); + run.setCharactersLength(text.textLength() - lastSpace); + ASSERT(run.charactersLength() >= run.length()); + + run.setTabSize(!collapseWhiteSpace, style.tabSize()); + run.setXPos(xPos + lastSpaceWordSpacing); + + unsigned prefixLength = font.offsetForPosition(run, maxPrefixWidth, false); + if (prefixLength < minimumPrefixLength) + return; + + prefixLength = lastHyphenLocation(StringView(text.text()).substring(lastSpace, pos - lastSpace), std::min(prefixLength, pos - lastSpace - minimumSuffixLength) + 1, localeIdentifier); + if (!prefixLength || prefixLength < minimumPrefixLength) + return; + + // When lastSpace is a space, which it always is except sometimes at the beginning of a line or after collapsed + // space, it should not count towards hyphenate-limit-before. + if (prefixLength == minimumPrefixLength) { + UChar characterAtLastSpace = text.characterAt(lastSpace); + if (characterAtLastSpace == ' ' || characterAtLastSpace == '\n' || characterAtLastSpace == '\t' || characterAtLastSpace == noBreakSpace) + return; + } + + ASSERT(pos - lastSpace - prefixLength >= minimumSuffixLength); + +#if !ASSERT_DISABLED + HashSet<const Font*> fallbackFonts; + float prefixWidth = hyphenWidth + textWidth(text, lastSpace, prefixLength, font, xPos, isFixedPitch, collapseWhiteSpace, fallbackFonts) + lastSpaceWordSpacing; + ASSERT(xPos + prefixWidth <= availableWidth); +#else + UNUSED_PARAM(isFixedPitch); +#endif + + lineBreak.moveTo(text, lastSpace + prefixLength, nextBreakable); + hyphenated = true; +} + +inline float BreakingContext::computeAdditionalBetweenWordsWidth(RenderText& renderText, TextLayout* textLayout, UChar currentCharacter, WordTrailingSpace& wordTrailingSpace, HashSet<const Font*>& fallbackFonts, WordMeasurements& wordMeasurements, const FontCascade& font, bool isFixedPitch, unsigned lastSpace, float lastSpaceWordSpacing, float wordSpacingForWordMeasurement, unsigned offset) +{ + wordMeasurements.grow(wordMeasurements.size() + 1); + WordMeasurement& wordMeasurement = wordMeasurements.last(); + + wordMeasurement.renderer = &renderText; + wordMeasurement.endOffset = offset; + wordMeasurement.startOffset = lastSpace; + + float additionalTempWidth = 0; + std::optional<float> wordTrailingSpaceWidth; + if (currentCharacter == ' ') + wordTrailingSpaceWidth = wordTrailingSpace.width(fallbackFonts); + if (wordTrailingSpaceWidth) + additionalTempWidth = textWidth(renderText, lastSpace, offset + 1 - lastSpace, font, m_width.currentWidth(), isFixedPitch, m_collapseWhiteSpace, wordMeasurement.fallbackFonts, textLayout) - wordTrailingSpaceWidth.value(); + else + additionalTempWidth = textWidth(renderText, lastSpace, offset - lastSpace, font, m_width.currentWidth(), isFixedPitch, m_collapseWhiteSpace, wordMeasurement.fallbackFonts, textLayout); + + if (wordMeasurement.fallbackFonts.isEmpty() && !fallbackFonts.isEmpty()) + wordMeasurement.fallbackFonts.swap(fallbackFonts); + fallbackFonts.clear(); + + wordMeasurement.width = additionalTempWidth + wordSpacingForWordMeasurement; + additionalTempWidth += lastSpaceWordSpacing; + return additionalTempWidth; +} + +inline bool BreakingContext::handleText(WordMeasurements& wordMeasurements, bool& hyphenated, unsigned& consecutiveHyphenatedLines) +{ + if (!m_current.offset()) + m_appliedStartWidth = false; + + RenderObject& renderObject = *m_current.renderer(); + RenderText& renderText = downcast<RenderText>(renderObject); + + bool isSVGText = renderText.isSVGInlineText(); + + // If we have left a no-wrap inline and entered an autowrap inline while ignoring spaces + // then we need to mark the start of the autowrap inline as a potential linebreak now. + if (m_autoWrap && !RenderStyle::autoWrap(m_lastWS) && m_ignoringSpaces) + commitLineBreakAtCurrentWidth(renderText); + + if (renderText.style().hasTextCombine() && is<RenderCombineText>(*m_current.renderer())) { + auto& combineRenderer = downcast<RenderCombineText>(*m_current.renderer()); + combineRenderer.combineText(); + // The length of the renderer's text may have changed. Increment stale iterator positions + if (iteratorIsBeyondEndOfRenderCombineText(m_lineBreakHistory.current(), combineRenderer)) { + ASSERT(iteratorIsBeyondEndOfRenderCombineText(m_resolver.position(), combineRenderer)); + m_lineBreakHistory.increment(); + m_resolver.increment(); + } + } + + const RenderStyle& style = lineStyle(renderText, m_lineInfo); + const FontCascade& font = style.fontCascade(); + bool isFixedPitch = font.isFixedPitch(); + bool canHyphenate = style.hyphens() == HyphensAuto && WebCore::canHyphenate(style.locale()); + bool canHangPunctuationAtStart = style.hangingPunctuation() & FirstHangingPunctuation; + bool canHangPunctuationAtEnd = style.hangingPunctuation() & LastHangingPunctuation; + bool canHangStopOrCommaAtLineEnd = style.hangingPunctuation() & AllowEndHangingPunctuation; + int endPunctuationIndex = canHangPunctuationAtEnd && m_collapseWhiteSpace ? renderText.lastCharacterIndexStrippingSpaces() : renderText.textLength() - 1; + unsigned lastSpace = m_current.offset(); + float wordSpacing = m_currentStyle->fontCascade().wordSpacing(); + float lastSpaceWordSpacing = 0; + float wordSpacingForWordMeasurement = 0; + + float wrapWidthOffset = m_width.uncommittedWidth() + inlineLogicalWidth(m_current.renderer(), !m_appliedStartWidth, true); + float wrapW = wrapWidthOffset; + float charWidth = 0; + bool breakNBSP = m_autoWrap && m_currentStyle->nbspMode() == SPACE; + // Auto-wrapping text should wrap in the middle of a word only if it could not wrap before the word, + // which is only possible if the word is the first thing on the line. + bool breakWords = m_currentStyle->breakWords() && ((m_autoWrap && (!m_width.committedWidth() && !m_width.hasCommittedReplaced())) || m_currWS == PRE); + bool midWordBreak = false; + bool breakAll = m_currentStyle->wordBreak() == BreakAllWordBreak && m_autoWrap; + bool keepAllWords = m_currentStyle->wordBreak() == KeepAllWordBreak; + float hyphenWidth = 0; + auto iteratorMode = mapLineBreakToIteratorMode(m_blockStyle.lineBreak()); + bool canUseLineBreakShortcut = iteratorMode == LineBreakIteratorMode::Default; + bool isLineEmpty = m_lineInfo.isEmpty(); + + if (isSVGText) { + breakWords = false; + breakAll = false; + } + + if (m_renderTextInfo.text != &renderText) { + updateCounterIfNeeded(renderText); + m_renderTextInfo.text = &renderText; + m_renderTextInfo.font = &font; + m_renderTextInfo.layout = font.createLayout(renderText, m_width.currentWidth(), m_collapseWhiteSpace); + m_renderTextInfo.lineBreakIterator.resetStringAndReleaseIterator(renderText.text(), style.locale(), iteratorMode); + } else if (m_renderTextInfo.layout && m_renderTextInfo.font != &font) { + m_renderTextInfo.font = &font; + m_renderTextInfo.layout = font.createLayout(renderText, m_width.currentWidth(), m_collapseWhiteSpace); + } + + TextLayout* textLayout = m_renderTextInfo.layout.get(); + + // Non-zero only when kerning is enabled and TextLayout isn't used, in which case we measure + // words with their trailing space, then subtract its width. + HashSet<const Font*> fallbackFonts; + UChar lastCharacterFromPreviousRenderText = m_renderTextInfo.lineBreakIterator.lastCharacter(); + UChar lastCharacter = m_renderTextInfo.lineBreakIterator.lastCharacter(); + UChar secondToLastCharacter = m_renderTextInfo.lineBreakIterator.secondToLastCharacter(); + WordTrailingSpace wordTrailingSpace(style, textLayout); + for (; m_current.offset() < renderText.textLength(); m_current.fastIncrementInTextNode()) { + bool previousCharacterIsSpace = m_currentCharacterIsSpace; + bool previousCharacterIsWS = m_currentCharacterIsWS; + UChar c = m_current.current(); + m_currentCharacterIsSpace = c == ' ' || c == '\t' || (!m_preservesNewline && (c == '\n')); + + if (canHangPunctuationAtStart && m_width.isFirstLine() && !m_width.committedWidth() && !wrapW && !inlineLogicalWidth(m_current.renderer(), true, false)) { + m_width.addUncommittedWidth(-renderText.hangablePunctuationStartWidth(m_current.offset())); + canHangPunctuationAtStart = false; + } + + if (canHangPunctuationAtEnd && !m_nextObject && (int)m_current.offset() == endPunctuationIndex && !inlineLogicalWidth(m_current.renderer(), false, true)) { + m_width.addUncommittedWidth(-renderText.hangablePunctuationEndWidth(endPunctuationIndex)); + canHangPunctuationAtEnd = false; + } + + if (!m_collapseWhiteSpace || !m_currentCharacterIsSpace) + m_lineInfo.setEmpty(false, &m_block, &m_width); + + if (c == softHyphen && m_autoWrap && !hyphenWidth && style.hyphens() != HyphensNone) { + hyphenWidth = measureHyphenWidth(renderText, font, &fallbackFonts); + m_width.addUncommittedWidth(hyphenWidth); + } + + bool applyWordSpacing = false; + + m_currentCharacterIsWS = m_currentCharacterIsSpace || (breakNBSP && c == noBreakSpace); + + if ((breakAll || breakWords) && !midWordBreak && (!m_currentCharacterIsSpace || style.whiteSpace() != PRE_WRAP)) { + wrapW += charWidth; + bool midWordBreakIsBeforeSurrogatePair = U16_IS_LEAD(c) && m_current.offset() + 1 < renderText.textLength() && U16_IS_TRAIL(renderText[m_current.offset() + 1]); + charWidth = textWidth(renderText, m_current.offset(), midWordBreakIsBeforeSurrogatePair ? 2 : 1, font, m_width.committedWidth() + wrapW, isFixedPitch, m_collapseWhiteSpace, fallbackFonts, textLayout); + midWordBreak = m_width.committedWidth() + wrapW + charWidth > m_width.availableWidth(); + } + + std::optional<unsigned> nextBreakablePosition = m_current.nextBreakablePosition(); + bool betweenWords = c == '\n' || (m_currWS != PRE && !m_atStart && isBreakable(m_renderTextInfo.lineBreakIterator, m_current.offset(), nextBreakablePosition, breakNBSP, canUseLineBreakShortcut, keepAllWords) + && (style.hyphens() != HyphensNone || (m_current.previousInSameNode() != softHyphen))); + m_current.setNextBreakablePosition(nextBreakablePosition); + + if (canHangStopOrCommaAtLineEnd && renderText.isHangableStopOrComma(c) && m_width.fitsOnLine()) { + // We need to see if a measurement that excludes the stop would fit. If so, then we should hang + // the stop/comma at the end. First measure including the comma. + m_hangsAtEnd = false; + float inlineStartWidth = !m_appliedStartWidth ? inlineLogicalWidth(m_current.renderer(), true, false) : LayoutUnit(); + float widthIncludingComma = computeAdditionalBetweenWordsWidth(renderText, textLayout, c, wordTrailingSpace, fallbackFonts, wordMeasurements, font, isFixedPitch, lastSpace, lastSpaceWordSpacing, wordSpacingForWordMeasurement, m_current.offset() + 1) + inlineStartWidth; + m_width.addUncommittedWidth(widthIncludingComma); + if (!m_width.fitsOnLine()) { + // See if we fit without the comma involved. If we do, then this is a potential hang point. + float widthWithoutStopOrComma = computeAdditionalBetweenWordsWidth(renderText, textLayout, lastCharacter, wordTrailingSpace, fallbackFonts, wordMeasurements, font, isFixedPitch, lastSpace, lastSpaceWordSpacing, wordSpacingForWordMeasurement, m_current.offset()) + inlineStartWidth; + m_width.addUncommittedWidth(widthWithoutStopOrComma - widthIncludingComma); + if (m_width.fitsOnLine()) + m_hangsAtEnd = true; + } else + m_width.addUncommittedWidth(-widthIncludingComma); + } + + if (betweenWords || midWordBreak) { + bool stoppedIgnoringSpaces = false; + if (m_ignoringSpaces) { + lastSpaceWordSpacing = 0; + if (!m_currentCharacterIsSpace) { + // Stop ignoring spaces and begin at this new point. + m_ignoringSpaces = false; + wordSpacingForWordMeasurement = 0; + lastSpace = m_current.offset(); // e.g., "Foo goo", don't add in any of the ignored spaces. + m_lineWhitespaceCollapsingState.stopIgnoringSpaces(InlineIterator(0, m_current.renderer(), m_current.offset())); + stoppedIgnoringSpaces = true; + } else { + // Just keep ignoring these spaces. + nextCharacter(c, lastCharacter, secondToLastCharacter); + continue; + } + } + + float additionalTempWidth = computeAdditionalBetweenWordsWidth(renderText, textLayout, c, wordTrailingSpace, fallbackFonts, wordMeasurements, font, isFixedPitch, lastSpace, lastSpaceWordSpacing, wordSpacingForWordMeasurement, m_current.offset()); + m_width.addUncommittedWidth(additionalTempWidth); + + WordMeasurement& wordMeasurement = wordMeasurements.last(); + + if (m_collapseWhiteSpace && previousCharacterIsSpace && m_currentCharacterIsSpace && additionalTempWidth) + m_width.setTrailingWhitespaceWidth(additionalTempWidth); + + if (!m_appliedStartWidth) { + float inlineStartWidth = inlineLogicalWidth(m_current.renderer(), true, false); + m_width.addUncommittedWidth(inlineStartWidth); + m_appliedStartWidth = true; + if (m_hangsAtEnd && inlineStartWidth) + m_hangsAtEnd = false; + } + + applyWordSpacing = wordSpacing && m_currentCharacterIsSpace; + + if (!m_width.hasCommitted() && m_autoWrap && !fitsOnLineOrHangsAtEnd()) + m_width.fitBelowFloats(m_lineInfo.isFirstLine()); + + if (m_autoWrap || breakWords) { + // If we break only after white-space, consider the current character + // as candidate width for this line. + bool lineWasTooWide = false; + if (fitsOnLineOrHangsAtEnd() && m_currentCharacterIsWS && m_currentStyle->breakOnlyAfterWhiteSpace() && !midWordBreak) { + float charWidth = textWidth(renderText, m_current.offset(), 1, font, m_width.currentWidth(), isFixedPitch, m_collapseWhiteSpace, wordMeasurement.fallbackFonts, textLayout) + (applyWordSpacing ? wordSpacing : 0); + // Check if line is too big even without the extra space + // at the end of the line. If it is not, do nothing. + // If the line needs the extra whitespace to be too long, + // then move the line break to the space and skip all + // additional whitespace. + if (!m_width.fitsOnLineIncludingExtraWidth(charWidth)) { + lineWasTooWide = true; + m_lineBreakHistory.push([&](InlineIterator& modifyMe) { + modifyMe.moveTo(renderObject, m_current.offset(), m_current.nextBreakablePosition()); + m_lineBreaker.skipTrailingWhitespace(modifyMe, m_lineInfo); + }); + } + } + if ((lineWasTooWide || !m_width.fitsOnLine()) && !m_hangsAtEnd) { + // Don't try to hyphenate at the final break of a block, since this means there is + // no more content, and a hyphenated single word would end up on a line by itself. This looks + // bad so just don't allow it. + if (canHyphenate && !m_width.fitsOnLine() && (m_nextObject || !renderText.containsOnlyWhitespace(m_current.offset(), renderText.textLength() - m_current.offset()) || isLineEmpty)) { + m_lineBreakHistory.push([&](InlineIterator& modifyMe) { + tryHyphenating(renderText, font, style.locale(), consecutiveHyphenatedLines, m_blockStyle.hyphenationLimitLines(), style.hyphenationLimitBefore(), style.hyphenationLimitAfter(), lastSpace, m_current.offset(), m_width.currentWidth() - additionalTempWidth, m_width.availableWidth(), isFixedPitch, m_collapseWhiteSpace, lastSpaceWordSpacing, modifyMe, m_current.nextBreakablePosition(), m_lineBreaker.m_hyphenated); + }); + if (m_lineBreaker.m_hyphenated) { + m_atEnd = true; + return false; + } + } + if (m_lineBreakHistory.atTextParagraphSeparator()) { + if (!stoppedIgnoringSpaces && m_current.offset() > 0) + ensureCharacterGetsLineBox(m_lineWhitespaceCollapsingState, m_current); + m_lineBreakHistory.increment(); + m_lineInfo.setPreviousLineBrokeCleanly(true); + wordMeasurement.endOffset = m_lineBreakHistory.offset(); + } + // Check if the last breaking position is a soft-hyphen. + if (!hyphenated && style.hyphens() != HyphensNone) { + std::optional<unsigned> lastBreakingPositon; + const RenderObject* rendererAtBreakingPosition = nullptr; + if (m_lineBreakHistory.offset() || m_lineBreakHistory.nextBreakablePosition()) { + lastBreakingPositon = m_lineBreakHistory.offset(); + rendererAtBreakingPosition = m_lineBreakHistory.renderer(); + } else if (m_current.nextBreakablePosition() && m_current.nextBreakablePosition().value() <= m_current.offset()) { + // We might just be right after the soft-hyphen + lastBreakingPositon = m_current.nextBreakablePosition().value(); + rendererAtBreakingPosition = m_current.renderer(); + } + if (lastBreakingPositon) { + std::optional<UChar> characterBeforeBreakingPosition; + // When last breaking position points to the start of the current context, we need to look at the last character from + // the previous non-empty text renderer. + if (!lastBreakingPositon.value()) + characterBeforeBreakingPosition = lastCharacterFromPreviousRenderText; + else if (is<RenderText>(rendererAtBreakingPosition)) { + const auto& textRenderer = downcast<RenderText>(*rendererAtBreakingPosition); + ASSERT(lastBreakingPositon.value() >= 1 && textRenderer.textLength() > (lastBreakingPositon.value() - 1)); + characterBeforeBreakingPosition = textRenderer.characterAt(lastBreakingPositon.value() - 1); + } + if (characterBeforeBreakingPosition) + hyphenated = characterBeforeBreakingPosition.value() == softHyphen; + } + } + if (m_lineBreakHistory.offset() && m_lineBreakHistory.offset() != (unsigned)wordMeasurement.endOffset && !wordMeasurement.width) { + if (charWidth) { + wordMeasurement.endOffset = m_lineBreakHistory.offset(); + wordMeasurement.width = charWidth; + } + } + // Didn't fit. Jump to the end unless there's still an opportunity to collapse whitespace. + if (m_ignoringSpaces || !m_collapseWhiteSpace || !m_currentCharacterIsSpace || !previousCharacterIsSpace) { + m_atEnd = true; + return false; + } + } else { + if (!betweenWords || (midWordBreak && !m_autoWrap)) + m_width.addUncommittedWidth(-additionalTempWidth); + if (hyphenWidth) { + // Subtract the width of the soft hyphen out since we fit on a line. + m_width.addUncommittedWidth(-hyphenWidth); + hyphenWidth = 0; + } + } + } + + if (c == '\n' && m_preservesNewline) { + if (!stoppedIgnoringSpaces && m_current.offset()) + ensureCharacterGetsLineBox(m_lineWhitespaceCollapsingState, m_current); + commitLineBreakAtCurrentWidth(renderObject, m_current.offset(), m_current.nextBreakablePosition()); + m_lineBreakHistory.increment(); + m_lineInfo.setPreviousLineBrokeCleanly(true); + return true; + } + + if (m_autoWrap && betweenWords) { + commitLineBreakAtCurrentWidth(renderObject, m_current.offset(), m_current.nextBreakablePosition()); + wrapWidthOffset = 0; + wrapW = wrapWidthOffset; + // Auto-wrapping text should not wrap in the middle of a word once it has had an + // opportunity to break after a word. + breakWords = false; + } + + if (midWordBreak && !U16_IS_TRAIL(c) && !(U_GET_GC_MASK(c) & U_GC_M_MASK)) { + // Remember this as a breakable position in case + // adding the end width forces a break. + m_lineBreakHistory.moveTo(renderObject, m_current.offset(), m_current.nextBreakablePosition()); + midWordBreak &= (breakWords || breakAll); + } + + if (betweenWords) { + lastSpaceWordSpacing = applyWordSpacing ? wordSpacing : 0; + wordSpacingForWordMeasurement = (applyWordSpacing && wordMeasurement.width) ? wordSpacing : 0; + lastSpace = m_current.offset(); + } + + if (!m_ignoringSpaces && m_currentStyle->collapseWhiteSpace()) { + // If we encounter a newline, or if we encounter a second space, + // we need to break up this run and enter a mode where we start collapsing spaces. + if (m_currentCharacterIsSpace && previousCharacterIsSpace) { + m_ignoringSpaces = true; + + // We just entered a mode where we are ignoring + // spaces. Create a transition to terminate the run + // before the second space. + m_lineWhitespaceCollapsingState.startIgnoringSpaces(m_startOfIgnoredSpaces); + m_trailingObjects.updateWhitespaceCollapsingTransitionsForTrailingBoxes(m_lineWhitespaceCollapsingState, InlineIterator(), TrailingObjects::DoNotCollapseFirstSpace); + } + } + // Measuring the width of complex text character-by-character, rather than measuring it all together, + // could produce considerably different width values. + if (!renderText.canUseSimpleFontCodePath() && midWordBreak && m_width.fitsOnLine()) { + midWordBreak = false; + wrapW = wrapWidthOffset + additionalTempWidth; + } + isLineEmpty = m_lineInfo.isEmpty(); + } else { + if (m_ignoringSpaces) { + // Stop ignoring spaces and begin at this new point. + m_ignoringSpaces = false; + lastSpaceWordSpacing = applyWordSpacing ? wordSpacing : 0; + wordSpacingForWordMeasurement = (applyWordSpacing && wordMeasurements.last().width) ? wordSpacing : 0; + lastSpace = m_current.offset(); // e.g., "Foo goo", don't add in any of the ignored spaces. + m_lineWhitespaceCollapsingState.stopIgnoringSpaces(InlineIterator(nullptr, m_current.renderer(), m_current.offset())); + } + if (m_hangsAtEnd && !renderText.isHangableStopOrComma(c)) + m_hangsAtEnd = false; + } + + if (isSVGText && m_current.offset()) { + // Force creation of new InlineBoxes for each absolute positioned character (those that start new text chunks). + if (downcast<RenderSVGInlineText>(renderText).characterStartsNewTextChunk(m_current.offset())) + ensureCharacterGetsLineBox(m_lineWhitespaceCollapsingState, m_current); + } + + if (m_currentCharacterIsSpace && !previousCharacterIsSpace) { + m_startOfIgnoredSpaces.setRenderer(m_current.renderer()); + m_startOfIgnoredSpaces.setOffset(m_current.offset()); + // Spaces after right-aligned text and before a line-break get collapsed away completely so that the trailing + // space doesn't seem to push the text out from the right-hand edge. + // FIXME: Do this regardless of the container's alignment - will require rebaselining a lot of test results. + if (m_nextObject && m_startOfIgnoredSpaces.offset() && m_nextObject->isBR() && (m_blockStyle.textAlign() == RIGHT || m_blockStyle.textAlign() == WEBKIT_RIGHT)) { + m_startOfIgnoredSpaces.setOffset(m_startOfIgnoredSpaces.offset() - 1); + // If there's just a single trailing space start ignoring it now so it collapses away. + if (m_current.offset() == renderText.textLength() - 1) + m_lineWhitespaceCollapsingState.startIgnoringSpaces(m_startOfIgnoredSpaces); + } + } + + if (!m_currentCharacterIsWS && previousCharacterIsWS) { + if (m_autoWrap && m_currentStyle->breakOnlyAfterWhiteSpace()) + m_lineBreakHistory.moveTo(renderObject, m_current.offset(), m_current.nextBreakablePosition()); + } + + if (m_collapseWhiteSpace && m_currentCharacterIsSpace && !m_ignoringSpaces) + m_trailingObjects.setTrailingWhitespace(downcast<RenderText>(m_current.renderer())); + else if (!m_currentStyle->collapseWhiteSpace() || !m_currentCharacterIsSpace) + m_trailingObjects.clear(); + + m_atStart = false; + nextCharacter(c, lastCharacter, secondToLastCharacter); + } + + m_renderTextInfo.lineBreakIterator.setPriorContext(lastCharacter, secondToLastCharacter); + + wordMeasurements.grow(wordMeasurements.size() + 1); + WordMeasurement& wordMeasurement = wordMeasurements.last(); + wordMeasurement.renderer = &renderText; + + // IMPORTANT: current.m_pos is > length here! + float additionalTempWidth = m_ignoringSpaces ? 0 : textWidth(renderText, lastSpace, m_current.offset() - lastSpace, font, m_width.currentWidth(), isFixedPitch, m_collapseWhiteSpace, wordMeasurement.fallbackFonts, textLayout); + wordMeasurement.startOffset = lastSpace; + wordMeasurement.endOffset = m_current.offset(); + wordMeasurement.width = m_ignoringSpaces ? 0 : additionalTempWidth + wordSpacingForWordMeasurement; + additionalTempWidth += lastSpaceWordSpacing; + + float inlineLogicalTempWidth = inlineLogicalWidth(m_current.renderer(), !m_appliedStartWidth, m_includeEndWidth); + m_width.addUncommittedWidth(additionalTempWidth + inlineLogicalTempWidth); + if (m_hangsAtEnd && inlineLogicalTempWidth) + m_hangsAtEnd = false; + + if (wordMeasurement.fallbackFonts.isEmpty() && !fallbackFonts.isEmpty()) + wordMeasurement.fallbackFonts.swap(fallbackFonts); + fallbackFonts.clear(); + + if (m_collapseWhiteSpace && m_currentCharacterIsSpace && additionalTempWidth) + m_width.setTrailingWhitespaceWidth(additionalTempWidth, inlineLogicalTempWidth); + + m_includeEndWidth = false; + + if (!fitsOnLineOrHangsAtEnd()) { + // Don't try to hyphenate at the final break of a block, since this means there is + // no more content, and a hyphenated single word would end up on a line by itself. This looks + // bad so just don't allow it. + if (canHyphenate && (m_nextObject || isLineEmpty)) { + m_lineBreakHistory.push([&](InlineIterator& modifyMe) { + tryHyphenating(renderText, font, style.locale(), consecutiveHyphenatedLines, m_blockStyle.hyphenationLimitLines(), style.hyphenationLimitBefore(), style.hyphenationLimitAfter(), lastSpace, m_current.offset(), m_width.currentWidth() - additionalTempWidth, m_width.availableWidth(), isFixedPitch, m_collapseWhiteSpace, lastSpaceWordSpacing, modifyMe, m_current.nextBreakablePosition(), m_lineBreaker.m_hyphenated); + }); + } + + if (!hyphenated && m_lineBreakHistory.previousInSameNode() == softHyphen && style.hyphens() != HyphensNone) { + hyphenated = true; + m_atEnd = true; + } + } + return false; +} + +inline bool textBeginsWithBreakablePosition(RenderText& nextText) +{ + UChar c = nextText.characterAt(0); + return c == ' ' || c == '\t' || (c == '\n' && !nextText.preservesNewline()); +} + +inline bool BreakingContext::canBreakAtThisPosition() +{ + // If we are no-wrap and have found a line-breaking opportunity already then we should take it. + if (m_width.committedWidth() && !m_width.fitsOnLine(m_currentCharacterIsSpace) && m_currWS == NOWRAP) + return true; + + // Avoid breaking on empty inlines. + if (is<RenderInline>(*m_current.renderer()) && isEmptyInline(downcast<RenderInline>(*m_current.renderer()))) + return false; + + // Avoid breaking before empty inlines (as long as the current object isn't replaced). + if (!m_current.renderer()->isReplaced() && is<RenderInline>(m_nextObject) && isEmptyInline(downcast<RenderInline>(*m_nextObject))) + return false; + + // Return early if we autowrap and the current character is a space as we will always want to break at such a position. + if (m_autoWrap && m_currentCharacterIsSpace) + return true; + + if (m_nextObject && m_nextObject->isLineBreakOpportunity()) + return m_autoWrap; + + bool nextIsAutoWrappingText = is<RenderText>(m_nextObject) && (m_autoWrap || m_nextObject->style().autoWrap()); + if (!nextIsAutoWrappingText) + return m_autoWrap; + RenderText& nextRenderText = downcast<RenderText>(*m_nextObject); + bool currentIsTextOrEmptyInline = is<RenderText>(*m_current.renderer()) || (is<RenderInline>(*m_current.renderer()) && isEmptyInline(downcast<RenderInline>(*m_current.renderer()))); + if (!currentIsTextOrEmptyInline) + return m_autoWrap && !m_current.renderer()->isRubyRun(); + + bool canBreakHere = !m_currentCharacterIsSpace && textBeginsWithBreakablePosition(nextRenderText); + + // See if attempting to fit below floats creates more available width on the line. + if (!m_width.fitsOnLine() && !m_width.hasCommitted()) + m_width.fitBelowFloats(m_lineInfo.isFirstLine()); + + bool canPlaceOnLine = m_width.fitsOnLine() || !m_autoWrapWasEverTrueOnLine; + + if (canPlaceOnLine && canBreakHere) + commitLineBreakAtCurrentWidth(nextRenderText); + + return canBreakHere; +} + +inline void BreakingContext::commitAndUpdateLineBreakIfNeeded() +{ + bool checkForBreak = canBreakAtThisPosition(); + + if (checkForBreak && !m_width.fitsOnLine(m_ignoringSpaces) && !m_hangsAtEnd) { + // if we have floats, try to get below them. + if (m_currentCharacterIsSpace && !m_ignoringSpaces && m_currentStyle->collapseWhiteSpace()) + m_trailingObjects.clear(); + + if (m_width.committedWidth()) { + m_atEnd = true; + return; + } + + if (!m_hangsAtEnd) + m_width.fitBelowFloats(m_lineInfo.isFirstLine()); + + // |width| may have been adjusted because we got shoved down past a float (thus + // giving us more room), so we need to retest, and only jump to + // the end label if we still don't fit on the line. -dwh + if (!m_width.fitsOnLine(m_ignoringSpaces)) { + m_atEnd = true; + return; + } + } else if (m_blockStyle.autoWrap() && !m_width.fitsOnLine() && !m_width.hasCommitted() && !m_hangsAtEnd) { + // If the container autowraps but the current child does not then we still need to ensure that it + // wraps and moves below any floats. + m_width.fitBelowFloats(m_lineInfo.isFirstLine()); + } + + if (!m_current.renderer()->isFloatingOrOutOfFlowPositioned()) { + m_lastObject = m_current.renderer(); + if (m_lastObject->isReplaced() && m_autoWrap && !m_lastObject->isRubyRun() && (!m_lastObject->isImage() || m_allowImagesToBreak) && (!is<RenderListMarker>(*m_lastObject) || downcast<RenderListMarker>(*m_lastObject).isInside())) { + if (m_nextObject) + commitLineBreakAtCurrentWidth(*m_nextObject); + else + commitLineBreakClear(); + } + } +} + +inline TrailingObjects::CollapseFirstSpaceOrNot checkWhitespaceCollapsingTransitions(LineWhitespaceCollapsingState& lineWhitespaceCollapsingState, const InlineIterator& lBreak) +{ + // Check to see if our last transition is a start point beyond the line break. If so, + // shave it off the list, and shave off a trailing space if the previous end point doesn't + // preserve whitespace. + if (lBreak.renderer() && lineWhitespaceCollapsingState.numTransitions() && !(lineWhitespaceCollapsingState.numTransitions() % 2)) { + const InlineIterator* transitions = lineWhitespaceCollapsingState.transitions().data(); + const InlineIterator& endpoint = transitions[lineWhitespaceCollapsingState.numTransitions() - 2]; + const InlineIterator& startpoint = transitions[lineWhitespaceCollapsingState.numTransitions() - 1]; + InlineIterator currpoint = endpoint; + while (!currpoint.atEnd() && currpoint != startpoint && currpoint != lBreak) + currpoint.increment(); + if (currpoint == lBreak) { + // We hit the line break before the start point. Shave off the start point. + lineWhitespaceCollapsingState.decrementNumTransitions(); + if (endpoint.renderer()->style().collapseWhiteSpace() && endpoint.renderer()->isText()) { + lineWhitespaceCollapsingState.decrementTransitionAt(lineWhitespaceCollapsingState.numTransitions() - 1); + return TrailingObjects::DoNotCollapseFirstSpace; + } + } + } + return TrailingObjects::CollapseFirstSpace; +} + +inline InlineIterator BreakingContext::handleEndOfLine() +{ + if (m_lineBreakHistory.current() == m_resolver.position()) { + if (!m_lineBreakHistory.renderer() || !m_lineBreakHistory.renderer()->isBR()) { + // we just add as much as possible + if (m_blockStyle.whiteSpace() == PRE && !m_current.offset()) { + if (m_lastObject) + commitLineBreakAtCurrentWidth(*m_lastObject, m_lastObject->isText() ? m_lastObject->length() : 0); + else + commitLineBreakClear(); + } + else if (m_lineBreakHistory.renderer()) { + // Don't ever break in the middle of a word if we can help it. + // There's no room at all. We just have to be on this line, + // even though we'll spill out. + commitLineBreakAtCurrentWidth(*m_current.renderer(), m_current.offset()); + } + } + // make sure we consume at least one char/object. + if (m_lineBreakHistory.current() == m_resolver.position()) + m_lineBreakHistory.increment(); + } else if (!m_current.offset() && !m_width.committedWidth() && m_width.uncommittedWidth() && !m_hadUncommittedWidthBeforeCurrent) { + // Do not push the current object to the next line, when this line has some content, but it is still considered empty. + // Empty inline elements like <span></span> can produce such lines and now we just ignore these break opportunities + // at the start of a line, if no width has been committed yet. + // Behave as if it was actually empty and consume at least one object. + m_lineBreakHistory.increment(); + } + + // Sanity check our whitespace collapsing transitions. + TrailingObjects::CollapseFirstSpaceOrNot collapsed = checkWhitespaceCollapsingTransitions(m_lineWhitespaceCollapsingState, m_lineBreakHistory.current()); + + m_trailingObjects.updateWhitespaceCollapsingTransitionsForTrailingBoxes(m_lineWhitespaceCollapsingState, m_lineBreakHistory.current(), collapsed); + + // We might have made lineBreak an iterator that points past the end + // of the object. Do this adjustment to make it point to the start + // of the next object instead to avoid confusing the rest of the + // code. + if (m_lineBreakHistory.offset()) { + m_lineBreakHistory.update([](InlineIterator& modifyMe) { + modifyMe.setOffset(modifyMe.offset() - 1); + modifyMe.increment(); + }); + } + +#if ENABLE(CSS_TRAILING_WORD) + if (m_blockStyle.trailingWord() == TrailingWord::PartiallyBalanced) + return optimalLineBreakLocationForTrailingWord(); +#endif + return m_lineBreakHistory.current(); +} + +#if ENABLE(CSS_TRAILING_WORD) +inline InlineIterator BreakingContext::optimalLineBreakLocationForTrailingWord() +{ + const unsigned longTrailingWordLength = 20; + const float optimalTrailingLineRatio = 0.1; + InlineIterator lineBreak = m_lineBreakHistory.current(); + if (!lineBreak.renderer() || !m_lineInfo.isFirstLine() || bidiNextSkippingEmptyInlines(*lineBreak.root(), lineBreak.renderer()) || !is<RenderText>(lineBreak.renderer())) + return lineBreak; + RenderText& renderText = downcast<RenderText>(*lineBreak.renderer()); + // Don't even bother measuring if our remaining line has many characters + if (renderText.textLength() == lineBreak.offset() || renderText.textLength() - lineBreak.offset() > longTrailingWordLength) + return lineBreak; + bool canUseLineBreakShortcut = m_renderTextInfo.lineBreakIterator.mode() == LineBreakIteratorMode::Default; + bool breakNBSP = m_autoWrap && m_currentStyle->nbspMode() == SPACE; + std::optional<unsigned> nextBreakablePosition = lineBreak.nextBreakablePosition(); + isBreakable(m_renderTextInfo.lineBreakIterator, lineBreak.offset() + 1, nextBreakablePosition, breakNBSP, canUseLineBreakShortcut, m_currentStyle->wordBreak() == KeepAllWordBreak); + if (!nextBreakablePosition || nextBreakablePosition.value() != renderText.textLength()) + return lineBreak; + const RenderStyle& style = lineStyle(renderText, m_lineInfo); + const FontCascade& font = style.fontCascade(); + HashSet<const Font*> dummyFonts; + InlineIterator best = lineBreak; + for (size_t i = 1; i < m_lineBreakHistory.historyLength(); ++i) { + const InlineIterator& candidate = m_lineBreakHistory.get(i); + if (candidate.renderer() != lineBreak.renderer()) + return best; + float width = textWidth(renderText, candidate.offset(), renderText.textLength() - candidate.offset(), font, 0, font.isFixedPitch(), m_collapseWhiteSpace, dummyFonts); + if (width > m_width.availableWidth()) + return best; + if (width / m_width.availableWidth() > optimalTrailingLineRatio) // Subsequent line is long enough + return candidate; + best = candidate; + } + return best; +} +#endif + +} |