webkitgtk-2.16.5HEADwebkitgtk-2.16.5master

1 files changed, 214 insertions, 0 deletions

diff --git a/Source/WebCore/rendering/BreakLines.h b/Source/WebCore/rendering/BreakLines.h
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+/*
+ * Copyright (C) 2005, 2007, 2010, 2013, 2016 Apple Inc. All rights reserved.
+ * Copyright (C) 2011 Google Inc. All rights 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 <unicode/ubrk.h>
+#include <wtf/ASCIICType.h>
+#include <wtf/StdLibExtras.h>
+#include <wtf/text/TextBreakIterator.h>
+#include <wtf/unicode/CharacterNames.h>
+
+namespace WebCore {
+
+static const UChar lineBreakTableFirstCharacter = '!';
+static const UChar lineBreakTableLastCharacter = 127;
+static const unsigned lineBreakTableColumnCount = (lineBreakTableLastCharacter - lineBreakTableFirstCharacter) / 8 + 1;
+
+WEBCORE_EXPORT extern const unsigned char lineBreakTable[][lineBreakTableColumnCount];
+
+enum class NonBreakingSpaceBehavior {
+    IgnoreNonBreakingSpace,
+    TreatNonBreakingSpaceAsBreak,
+};
+
+enum class CanUseShortcut {
+    Yes,
+    No
+};
+
+template<NonBreakingSpaceBehavior nonBreakingSpaceBehavior>
+static inline bool isBreakableSpace(UChar character)
+{
+    switch (character) {
+    case ' ':
+    case '\n':
+    case '\t':
+        return true;
+    case noBreakSpace:
+        return nonBreakingSpaceBehavior == NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak;
+    default:
+        return false;
+    }
+}
+
+inline bool shouldBreakAfter(UChar lastCharacter, UChar character, UChar nextCharacter)
+{
+    // Don't allow line breaking between '-' and a digit if the '-' may mean a minus sign in the context,
+    // while allow breaking in 'ABCD-1234' and '1234-5678' which may be in long URLs.
+    if (character == '-' && isASCIIDigit(nextCharacter))
+        return isASCIIAlphanumeric(lastCharacter);
+
+    // If both ch and nextCh are ASCII characters, use a lookup table for enhanced speed and for compatibility
+    // with other browsers (see comments for asciiLineBreakTable for details).
+    if (character >= lineBreakTableFirstCharacter && character <= lineBreakTableLastCharacter && nextCharacter >= lineBreakTableFirstCharacter && nextCharacter <= lineBreakTableLastCharacter) {
+        const unsigned char* tableRow = lineBreakTable[character - lineBreakTableFirstCharacter];
+        unsigned nextCharacterIndex = nextCharacter - lineBreakTableFirstCharacter;
+        return tableRow[nextCharacterIndex / 8] & (1 << (nextCharacterIndex % 8));
+    }
+    // Otherwise defer to the Unicode algorithm by returning false.
+    return false;
+}
+
+template<NonBreakingSpaceBehavior nonBreakingSpaceBehavior>
+inline bool needsLineBreakIterator(UChar character)
+{
+    if (nonBreakingSpaceBehavior == NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak)
+        return character > lineBreakTableLastCharacter;
+    return character > lineBreakTableLastCharacter && character != noBreakSpace;
+}
+
+// When in non-loose mode, we can use the ASCII shortcut table.
+template<typename CharacterType, NonBreakingSpaceBehavior nonBreakingSpaceBehavior, CanUseShortcut canUseShortcut>
+inline unsigned nextBreakablePosition(LazyLineBreakIterator& lazyBreakIterator, const CharacterType* string, unsigned length, unsigned startPosition)
+{
+    std::optional<unsigned> nextBreak;
+
+    CharacterType lastLastCharacter = startPosition > 1 ? string[startPosition - 2] : static_cast<CharacterType>(lazyBreakIterator.secondToLastCharacter());
+    CharacterType lastCharacter = startPosition > 0 ? string[startPosition - 1] : static_cast<CharacterType>(lazyBreakIterator.lastCharacter());
+    unsigned priorContextLength = lazyBreakIterator.priorContextLength();
+    for (unsigned i = startPosition; i < length; i++) {
+        CharacterType character = string[i];
+
+        if (isBreakableSpace<nonBreakingSpaceBehavior>(character) || (canUseShortcut == CanUseShortcut::Yes && shouldBreakAfter(lastLastCharacter, lastCharacter, character)))
+            return i;
+
+        if (canUseShortcut == CanUseShortcut::No || needsLineBreakIterator<nonBreakingSpaceBehavior>(character) || needsLineBreakIterator<nonBreakingSpaceBehavior>(lastCharacter)) {
+            if (!nextBreak || nextBreak.value() < i) {
+                // Don't break if positioned at start of primary context and there is no prior context.
+                if (i || priorContextLength) {
+                    UBreakIterator* breakIterator = lazyBreakIterator.get(priorContextLength);
+                    if (breakIterator) {
+                        int candidate = ubrk_following(breakIterator, i - 1 + priorContextLength);
+                        if (candidate == UBRK_DONE)
+                            nextBreak = std::nullopt;
+                        else {
+                            unsigned result = candidate;
+                            ASSERT(result >= priorContextLength);
+                            nextBreak = result - priorContextLength;
+                        }
+                    }
+                }
+            }
+            if (i == nextBreak && !isBreakableSpace<nonBreakingSpaceBehavior>(lastCharacter))
+                return i;
+        }
+
+        lastLastCharacter = lastCharacter;
+        lastCharacter = character;
+    }
+
+    return length;
+}
+
+template<typename CharacterType, NonBreakingSpaceBehavior nonBreakingSpaceBehavior>
+inline unsigned nextBreakablePositionKeepingAllWords(const CharacterType* string, unsigned length, unsigned startPosition)
+{
+    for (unsigned i = startPosition; i < length; i++) {
+        if (isBreakableSpace<nonBreakingSpaceBehavior>(string[i]))
+            return i;
+    }
+    return length;
+}
+
+inline unsigned nextBreakablePositionKeepingAllWords(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition)
+{
+    auto stringView = lazyBreakIterator.stringView();
+    if (stringView.is8Bit())
+        return nextBreakablePositionKeepingAllWords<LChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak>(stringView.characters8(), stringView.length(), startPosition);
+    return nextBreakablePositionKeepingAllWords<UChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak>(stringView.characters16(), stringView.length(), startPosition);
+}
+
+inline unsigned nextBreakablePositionKeepingAllWordsIgnoringNBSP(LazyLineBreakIterator& iterator, unsigned startPosition)
+{
+    auto stringView = iterator.stringView();
+    if (stringView.is8Bit())
+        return nextBreakablePositionKeepingAllWords<LChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace>(stringView.characters8(), stringView.length(), startPosition);
+    return nextBreakablePositionKeepingAllWords<UChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace>(stringView.characters16(), stringView.length(), startPosition);
+}
+
+inline unsigned nextBreakablePosition(LazyLineBreakIterator& iterator, unsigned startPosition)
+{
+    auto stringView = iterator.stringView();
+    if (stringView.is8Bit())
+        return nextBreakablePosition<LChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak, CanUseShortcut::Yes>(iterator, stringView.characters8(), stringView.length(), startPosition);
+    return nextBreakablePosition<UChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak, CanUseShortcut::Yes>(iterator, stringView.characters16(), stringView.length(), startPosition);
+}
+
+inline unsigned nextBreakablePositionIgnoringNBSP(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition)
+{
+    auto stringView = lazyBreakIterator.stringView();
+    if (stringView.is8Bit())
+        return nextBreakablePosition<LChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace, CanUseShortcut::Yes>(lazyBreakIterator, stringView.characters8(), stringView.length(), startPosition);
+    return nextBreakablePosition<UChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace, CanUseShortcut::Yes>(lazyBreakIterator, stringView.characters16(), stringView.length(), startPosition);
+}
+
+inline unsigned nextBreakablePositionWithoutShortcut(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition)
+{
+    auto stringView = lazyBreakIterator.stringView();
+    if (stringView.is8Bit())
+        return nextBreakablePosition<LChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak, CanUseShortcut::No>(lazyBreakIterator, stringView.characters8(), stringView.length(), startPosition);
+    return nextBreakablePosition<UChar, NonBreakingSpaceBehavior::TreatNonBreakingSpaceAsBreak, CanUseShortcut::No>(lazyBreakIterator, stringView.characters16(), stringView.length(), startPosition);
+}
+
+inline unsigned nextBreakablePositionIgnoringNBSPWithoutShortcut(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition)
+{
+    auto stringView = lazyBreakIterator.stringView();
+    if (stringView.is8Bit())
+        return nextBreakablePosition<LChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace, CanUseShortcut::No>(lazyBreakIterator, stringView.characters8(), stringView.length(), startPosition);
+    return nextBreakablePosition<UChar, NonBreakingSpaceBehavior::IgnoreNonBreakingSpace, CanUseShortcut::No>(lazyBreakIterator, stringView.characters16(), stringView.length(), startPosition);
+}
+
+inline bool isBreakable(LazyLineBreakIterator& lazyBreakIterator, unsigned startPosition, std::optional<unsigned>& nextBreakable, bool breakNBSP, bool canUseShortcut, bool keepAllWords)
+{
+    if (nextBreakable && nextBreakable.value() >= startPosition)
+        return startPosition == nextBreakable;
+
+    if (keepAllWords) {
+        if (breakNBSP)
+            nextBreakable = nextBreakablePositionKeepingAllWords(lazyBreakIterator, startPosition);
+        else
+            nextBreakable = nextBreakablePositionKeepingAllWordsIgnoringNBSP(lazyBreakIterator, startPosition);
+    } else if (!canUseShortcut) {
+        if (breakNBSP)
+            nextBreakable = nextBreakablePositionWithoutShortcut(lazyBreakIterator, startPosition);
+        else
+            nextBreakable = nextBreakablePositionIgnoringNBSPWithoutShortcut(lazyBreakIterator, startPosition);
+    } else {
+        if (breakNBSP)
+            nextBreakable = nextBreakablePosition(lazyBreakIterator, startPosition);
+        else
+            nextBreakable = nextBreakablePositionIgnoringNBSP(lazyBreakIterator, startPosition);
+    }
+    return startPosition == nextBreakable;
+}
+
+} // namespace WebCore