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-rw-r--r--dom/base/nsLineBreaker.cpp553
1 files changed, 553 insertions, 0 deletions
diff --git a/dom/base/nsLineBreaker.cpp b/dom/base/nsLineBreaker.cpp
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+++ b/dom/base/nsLineBreaker.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsLineBreaker.h"
+#include "nsContentUtils.h"
+#include "gfxTextRun.h" // for the gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_* values
+#include "nsHyphenationManager.h"
+#include "nsHyphenator.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/intl/LineBreaker.h" // for LineBreaker::ComputeBreakPositions
+#include "mozilla/intl/Locale.h"
+#include "mozilla/intl/UnicodeProperties.h"
+
+using mozilla::AutoRestore;
+using mozilla::intl::LineBreaker;
+using mozilla::intl::LineBreakRule;
+using mozilla::intl::Locale;
+using mozilla::intl::LocaleParser;
+using mozilla::intl::UnicodeProperties;
+using mozilla::intl::WordBreakRule;
+
+nsLineBreaker::nsLineBreaker()
+ : mCurrentWordLanguage(nullptr),
+ mCurrentWordContainsMixedLang(false),
+ mCurrentWordContainsComplexChar(false),
+ mScriptIsChineseOrJapanese(false),
+ mAfterBreakableSpace(false),
+ mBreakHere(false),
+ mWordBreak(WordBreakRule::Normal),
+ mLineBreak(LineBreakRule::Auto),
+ mWordContinuation(false) {}
+
+nsLineBreaker::~nsLineBreaker() {
+ NS_ASSERTION(mCurrentWord.Length() == 0,
+ "Should have Reset() before destruction!");
+}
+
+static void SetupCapitalization(const char16_t* aWord, uint32_t aLength,
+ bool* aCapitalization) {
+ // Capitalize the first alphanumeric character after a space or punctuation.
+ using mozilla::intl::GeneralCategory;
+ bool capitalizeNextChar = true;
+ for (uint32_t i = 0; i < aLength; ++i) {
+ uint32_t ch = aWord[i];
+ if (i + 1 < aLength && NS_IS_SURROGATE_PAIR(ch, aWord[i + 1])) {
+ ch = SURROGATE_TO_UCS4(ch, aWord[i + 1]);
+ }
+ auto category = UnicodeProperties::CharType(ch);
+ switch (category) {
+ case GeneralCategory::Uppercase_Letter:
+ case GeneralCategory::Lowercase_Letter:
+ case GeneralCategory::Titlecase_Letter:
+ case GeneralCategory::Modifier_Letter:
+ case GeneralCategory::Other_Letter:
+ case GeneralCategory::Decimal_Number:
+ case GeneralCategory::Letter_Number:
+ case GeneralCategory::Other_Number:
+ if (capitalizeNextChar) {
+ aCapitalization[i] = true;
+ capitalizeNextChar = false;
+ }
+ break;
+ case GeneralCategory::Space_Separator:
+ case GeneralCategory::Line_Separator:
+ case GeneralCategory::Paragraph_Separator:
+ case GeneralCategory::Dash_Punctuation:
+ case GeneralCategory::Initial_Punctuation:
+ /* These punctuation categories are excluded, for examples like
+ * "what colo[u]r" -> "What Colo[u]r?" (rather than "What Colo[U]R?")
+ * and
+ * "snake_case" -> "Snake_case" (to match word selection behavior)
+ case GeneralCategory::Open_Punctuation:
+ case GeneralCategory::Close_Punctuation:
+ case GeneralCategory::Connector_Punctuation:
+ */
+ capitalizeNextChar = true;
+ break;
+ case GeneralCategory::Final_Punctuation:
+ /* Special-case: exclude Unicode single-close-quote/apostrophe,
+ for examples like "Lowe’s" etc. */
+ if (ch != 0x2019) {
+ capitalizeNextChar = true;
+ }
+ break;
+ case GeneralCategory::Other_Punctuation:
+ /* Special-case: exclude ASCII apostrophe, for "Lowe's" etc. */
+ if (ch != '\'') {
+ capitalizeNextChar = true;
+ }
+ break;
+ default:
+ break;
+ }
+ if (!IS_IN_BMP(ch)) {
+ ++i;
+ }
+ }
+}
+
+nsresult nsLineBreaker::FlushCurrentWord() {
+ uint32_t length = mCurrentWord.Length();
+ AutoTArray<uint8_t, 4000> breakState;
+ if (!breakState.AppendElements(length, mozilla::fallible)) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+
+ if (mLineBreak == LineBreakRule::Anywhere) {
+ memset(breakState.Elements(),
+ gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NORMAL,
+ length * sizeof(uint8_t));
+ } else if (!mCurrentWordContainsComplexChar) {
+ // For break-strict set everything internal to "break", otherwise
+ // to "no break"!
+ memset(breakState.Elements(),
+ mWordBreak == WordBreakRule::BreakAll
+ ? gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NORMAL
+ : gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NONE,
+ length * sizeof(uint8_t));
+ } else {
+ LineBreaker::ComputeBreakPositions(
+ mCurrentWord.Elements(), length, mWordBreak, mLineBreak,
+ mScriptIsChineseOrJapanese, breakState.Elements());
+ }
+
+ bool autoHyphenate = mCurrentWordLanguage && !mCurrentWordContainsMixedLang;
+ uint32_t i;
+ for (i = 0; autoHyphenate && i < mTextItems.Length(); ++i) {
+ TextItem* ti = &mTextItems[i];
+ if (!(ti->mFlags & BREAK_USE_AUTO_HYPHENATION)) {
+ autoHyphenate = false;
+ }
+ }
+ if (autoHyphenate) {
+ RefPtr<nsHyphenator> hyphenator =
+ nsHyphenationManager::Instance()->GetHyphenator(mCurrentWordLanguage);
+ if (hyphenator) {
+ FindHyphenationPoints(hyphenator, mCurrentWord.Elements(),
+ mCurrentWord.Elements() + length,
+ breakState.Elements());
+ }
+ }
+
+ nsTArray<bool> capitalizationState;
+ uint32_t offset = 0;
+ for (i = 0; i < mTextItems.Length(); ++i) {
+ TextItem* ti = &mTextItems[i];
+ NS_ASSERTION(ti->mLength > 0, "Zero length word contribution?");
+
+ if ((ti->mFlags & BREAK_SUPPRESS_INITIAL) && ti->mSinkOffset == 0) {
+ breakState[offset] = gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NONE;
+ }
+ if (ti->mFlags & BREAK_SUPPRESS_INSIDE) {
+ uint32_t exclude = ti->mSinkOffset == 0 ? 1 : 0;
+ memset(breakState.Elements() + offset + exclude,
+ gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NONE,
+ (ti->mLength - exclude) * sizeof(uint8_t));
+ }
+
+ // Don't set the break state for the first character of the word, because
+ // it was already set correctly earlier and we don't know what the true
+ // value should be.
+ uint32_t skipSet = i == 0 ? 1 : 0;
+ if (ti->mSink) {
+ ti->mSink->SetBreaks(ti->mSinkOffset + skipSet, ti->mLength - skipSet,
+ breakState.Elements() + offset + skipSet);
+
+ if (!mWordContinuation && (ti->mFlags & BREAK_NEED_CAPITALIZATION)) {
+ if (capitalizationState.Length() == 0) {
+ if (!capitalizationState.AppendElements(length, mozilla::fallible)) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ };
+ memset(capitalizationState.Elements(), false, length * sizeof(bool));
+ SetupCapitalization(mCurrentWord.Elements(), length,
+ capitalizationState.Elements());
+ }
+ ti->mSink->SetCapitalization(ti->mSinkOffset, ti->mLength,
+ capitalizationState.Elements() + offset);
+ }
+ }
+
+ offset += ti->mLength;
+ }
+
+ mCurrentWord.Clear();
+ mTextItems.Clear();
+ mCurrentWordContainsComplexChar = false;
+ mCurrentWordContainsMixedLang = false;
+ mCurrentWordLanguage = nullptr;
+ mWordContinuation = false;
+ return NS_OK;
+}
+
+// If the aFlags parameter to AppendText has all these bits set,
+// then we don't need to worry about finding break opportunities
+// in the appended text.
+#define NO_BREAKS_NEEDED_FLAGS \
+ (BREAK_SUPPRESS_INITIAL | BREAK_SUPPRESS_INSIDE | \
+ BREAK_SKIP_SETTING_NO_BREAKS)
+
+nsresult nsLineBreaker::AppendText(nsAtom* aHyphenationLanguage,
+ const char16_t* aText, uint32_t aLength,
+ uint32_t aFlags, nsILineBreakSink* aSink) {
+ NS_ASSERTION(aLength > 0, "Appending empty text...");
+
+ uint32_t offset = 0;
+
+ // Continue the current word
+ if (mCurrentWord.Length() > 0) {
+ NS_ASSERTION(!mAfterBreakableSpace && !mBreakHere,
+ "These should not be set");
+
+ while (offset < aLength && !IsSpace(aText[offset])) {
+ mCurrentWord.AppendElement(aText[offset]);
+ if (!mCurrentWordContainsComplexChar && IsComplexChar(aText[offset])) {
+ mCurrentWordContainsComplexChar = true;
+ }
+ UpdateCurrentWordLanguage(aHyphenationLanguage);
+ ++offset;
+ }
+
+ if (offset > 0) {
+ mTextItems.AppendElement(TextItem(aSink, 0, offset, aFlags));
+ }
+
+ if (offset == aLength) return NS_OK;
+
+ // We encountered whitespace, so we're done with this word
+ nsresult rv = FlushCurrentWord();
+ if (NS_FAILED(rv)) return rv;
+ }
+
+ AutoTArray<uint8_t, 4000> breakState;
+ if (aSink) {
+ if (!breakState.AppendElements(aLength, mozilla::fallible)) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+ }
+
+ bool noCapitalizationNeeded = true;
+ nsTArray<bool> capitalizationState;
+ if (aSink && (aFlags & BREAK_NEED_CAPITALIZATION)) {
+ if (!capitalizationState.AppendElements(aLength, mozilla::fallible)) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+ memset(capitalizationState.Elements(), false, aLength * sizeof(bool));
+ noCapitalizationNeeded = false;
+ }
+
+ uint32_t start = offset;
+ bool noBreaksNeeded =
+ !aSink || ((aFlags & NO_BREAKS_NEEDED_FLAGS) == NO_BREAKS_NEEDED_FLAGS &&
+ !mBreakHere && !mAfterBreakableSpace);
+ if (noBreaksNeeded && noCapitalizationNeeded) {
+ // Skip to the space before the last word, since either the break data
+ // here is not needed, or no breaks are set in the sink and there cannot
+ // be any breaks in this chunk; and we don't need to do word-initial
+ // capitalization. All we need is the context for the next chunk (if any).
+ offset = aLength;
+ while (offset > start) {
+ --offset;
+ if (IsSpace(aText[offset])) break;
+ }
+ }
+ uint32_t wordStart = offset;
+ bool wordHasComplexChar = false;
+
+ RefPtr<nsHyphenator> hyphenator;
+ if ((aFlags & BREAK_USE_AUTO_HYPHENATION) &&
+ !(aFlags & BREAK_SUPPRESS_INSIDE) && aHyphenationLanguage) {
+ hyphenator =
+ nsHyphenationManager::Instance()->GetHyphenator(aHyphenationLanguage);
+ }
+
+ for (;;) {
+ char16_t ch = aText[offset];
+ bool isSpace = IsSpace(ch);
+ bool isBreakableSpace = isSpace && !(aFlags & BREAK_SUPPRESS_INSIDE);
+
+ if (aSink && !noBreaksNeeded) {
+ breakState[offset] =
+ mBreakHere || (mAfterBreakableSpace && !isBreakableSpace) ||
+ mWordBreak == WordBreakRule::BreakAll ||
+ mLineBreak == LineBreakRule::Anywhere
+ ? gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NORMAL
+ : gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NONE;
+ }
+ mBreakHere = false;
+ mAfterBreakableSpace = isBreakableSpace;
+
+ if (isSpace || ch == '\n') {
+ if (offset > wordStart && aSink) {
+ if (!(aFlags & BREAK_SUPPRESS_INSIDE)) {
+ if (mLineBreak == LineBreakRule::Anywhere) {
+ memset(breakState.Elements() + wordStart,
+ gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NORMAL,
+ offset - wordStart);
+ } else if (wordHasComplexChar) {
+ // Save current start-of-word state because ComputeBreakPositions()
+ // will set it to false.
+ AutoRestore<uint8_t> saveWordStartBreakState(breakState[wordStart]);
+ LineBreaker::ComputeBreakPositions(
+ aText + wordStart, offset - wordStart, mWordBreak, mLineBreak,
+ mScriptIsChineseOrJapanese, breakState.Elements() + wordStart);
+ }
+ if (hyphenator) {
+ FindHyphenationPoints(hyphenator, aText + wordStart, aText + offset,
+ breakState.Elements() + wordStart);
+ }
+ }
+ if (!mWordContinuation && !noCapitalizationNeeded) {
+ SetupCapitalization(aText + wordStart, offset - wordStart,
+ capitalizationState.Elements() + wordStart);
+ }
+ }
+ wordHasComplexChar = false;
+ mWordContinuation = false;
+ ++offset;
+ if (offset >= aLength) break;
+ wordStart = offset;
+ } else {
+ if (!wordHasComplexChar && IsComplexChar(ch)) {
+ wordHasComplexChar = true;
+ }
+ ++offset;
+ if (offset >= aLength) {
+ // Save this word
+ mCurrentWordContainsComplexChar = wordHasComplexChar;
+ uint32_t len = offset - wordStart;
+ char16_t* elems = mCurrentWord.AppendElements(len);
+ if (!elems) return NS_ERROR_OUT_OF_MEMORY;
+ memcpy(elems, aText + wordStart, sizeof(char16_t) * len);
+ mTextItems.AppendElement(TextItem(aSink, wordStart, len, aFlags));
+ // Ensure that the break-before for this word is written out
+ offset = wordStart + 1;
+ UpdateCurrentWordLanguage(aHyphenationLanguage);
+ break;
+ }
+ }
+ }
+
+ if (aSink) {
+ if (!noBreaksNeeded) {
+ aSink->SetBreaks(start, offset - start, breakState.Elements() + start);
+ }
+ if (!noCapitalizationNeeded) {
+ aSink->SetCapitalization(start, offset - start,
+ capitalizationState.Elements() + start);
+ }
+ }
+ return NS_OK;
+}
+
+void nsLineBreaker::FindHyphenationPoints(nsHyphenator* aHyphenator,
+ const char16_t* aTextStart,
+ const char16_t* aTextLimit,
+ uint8_t* aBreakState) {
+ nsDependentSubstring string(aTextStart, aTextLimit);
+ AutoTArray<bool, 200> hyphens;
+ if (NS_SUCCEEDED(aHyphenator->Hyphenate(string, hyphens))) {
+ for (uint32_t i = 0; i + 1 < string.Length(); ++i) {
+ if (hyphens[i]) {
+ aBreakState[i + 1] =
+ gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_HYPHEN;
+ }
+ }
+ }
+}
+
+nsresult nsLineBreaker::AppendText(nsAtom* aHyphenationLanguage,
+ const uint8_t* aText, uint32_t aLength,
+ uint32_t aFlags, nsILineBreakSink* aSink) {
+ NS_ASSERTION(aLength > 0, "Appending empty text...");
+
+ if (aFlags & (BREAK_NEED_CAPITALIZATION | BREAK_USE_AUTO_HYPHENATION)) {
+ // Defer to the Unicode path if capitalization or hyphenation is required
+ nsAutoString str;
+ const char* cp = reinterpret_cast<const char*>(aText);
+ CopyASCIItoUTF16(nsDependentCSubstring(cp, cp + aLength), str);
+ return AppendText(aHyphenationLanguage, str.get(), aLength, aFlags, aSink);
+ }
+
+ uint32_t offset = 0;
+
+ // Continue the current word
+ if (mCurrentWord.Length() > 0) {
+ NS_ASSERTION(!mAfterBreakableSpace && !mBreakHere,
+ "These should not be set");
+
+ while (offset < aLength && !IsSpace(aText[offset])) {
+ mCurrentWord.AppendElement(aText[offset]);
+ if (!mCurrentWordContainsComplexChar &&
+ IsComplexASCIIChar(aText[offset])) {
+ mCurrentWordContainsComplexChar = true;
+ }
+ ++offset;
+ }
+
+ if (offset > 0) {
+ mTextItems.AppendElement(TextItem(aSink, 0, offset, aFlags));
+ }
+
+ if (offset == aLength) {
+ // We did not encounter whitespace so the word hasn't finished yet.
+ return NS_OK;
+ }
+
+ // We encountered whitespace, so we're done with this word
+ nsresult rv = FlushCurrentWord();
+ if (NS_FAILED(rv)) return rv;
+ }
+
+ AutoTArray<uint8_t, 4000> breakState;
+ if (aSink) {
+ if (!breakState.AppendElements(aLength, mozilla::fallible)) {
+ return NS_ERROR_OUT_OF_MEMORY;
+ }
+ }
+
+ uint32_t start = offset;
+ bool noBreaksNeeded =
+ !aSink || ((aFlags & NO_BREAKS_NEEDED_FLAGS) == NO_BREAKS_NEEDED_FLAGS &&
+ !mBreakHere && !mAfterBreakableSpace);
+ if (noBreaksNeeded) {
+ // Skip to the space before the last word, since either the break data
+ // here is not needed, or no breaks are set in the sink and there cannot
+ // be any breaks in this chunk; all we need is the context for the next
+ // chunk (if any)
+ offset = aLength;
+ while (offset > start) {
+ --offset;
+ if (IsSpace(aText[offset])) break;
+ }
+ }
+ uint32_t wordStart = offset;
+ bool wordHasComplexChar = false;
+
+ for (;;) {
+ uint8_t ch = aText[offset];
+ bool isSpace = IsSpace(ch);
+ bool isBreakableSpace = isSpace && !(aFlags & BREAK_SUPPRESS_INSIDE);
+
+ if (aSink) {
+ // Consider word-break style. Since the break position of CJK scripts
+ // will be set by nsILineBreaker, we don't consider CJK at this point.
+ breakState[offset] =
+ mBreakHere || (mAfterBreakableSpace && !isBreakableSpace) ||
+ mWordBreak == WordBreakRule::BreakAll ||
+ mLineBreak == LineBreakRule::Anywhere
+ ? gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NORMAL
+ : gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NONE;
+ }
+ mBreakHere = false;
+ mAfterBreakableSpace = isBreakableSpace;
+
+ if (isSpace) {
+ if (offset > wordStart && aSink && !(aFlags & BREAK_SUPPRESS_INSIDE)) {
+ if (mLineBreak == LineBreakRule::Anywhere) {
+ memset(breakState.Elements() + wordStart,
+ gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NORMAL,
+ offset - wordStart);
+ } else if (wordHasComplexChar) {
+ // Save current start-of-word state because ComputeBreakPositions()
+ // will set it to false.
+ AutoRestore<uint8_t> saveWordStartBreakState(breakState[wordStart]);
+ LineBreaker::ComputeBreakPositions(
+ aText + wordStart, offset - wordStart, mWordBreak, mLineBreak,
+ mScriptIsChineseOrJapanese, breakState.Elements() + wordStart);
+ }
+ }
+
+ wordHasComplexChar = false;
+ ++offset;
+ if (offset >= aLength) break;
+ wordStart = offset;
+ } else {
+ if (!wordHasComplexChar && IsComplexASCIIChar(ch)) {
+ wordHasComplexChar = true;
+ }
+ ++offset;
+ if (offset >= aLength) {
+ // Save this word
+ mCurrentWordContainsComplexChar = wordHasComplexChar;
+ uint32_t len = offset - wordStart;
+ char16_t* elems = mCurrentWord.AppendElements(len);
+ if (!elems) return NS_ERROR_OUT_OF_MEMORY;
+ uint32_t i;
+ for (i = wordStart; i < offset; ++i) {
+ elems[i - wordStart] = aText[i];
+ }
+ mTextItems.AppendElement(TextItem(aSink, wordStart, len, aFlags));
+ // Ensure that the break-before for this word is written out
+ offset = wordStart + 1;
+ break;
+ }
+ }
+ }
+
+ if (!noBreaksNeeded) {
+ aSink->SetBreaks(start, offset - start, breakState.Elements() + start);
+ }
+ return NS_OK;
+}
+
+void nsLineBreaker::UpdateCurrentWordLanguage(nsAtom* aHyphenationLanguage) {
+ if (mCurrentWordLanguage && mCurrentWordLanguage != aHyphenationLanguage) {
+ mCurrentWordContainsMixedLang = true;
+ mScriptIsChineseOrJapanese = false;
+ } else {
+ if (aHyphenationLanguage && !mCurrentWordLanguage) {
+ Locale loc;
+ auto result =
+ LocaleParser::TryParse(nsAtomCString(aHyphenationLanguage), loc);
+
+ if (result.isErr()) {
+ return;
+ }
+ if (loc.Script().Missing() && loc.AddLikelySubtags().isErr()) {
+ return;
+ }
+ mScriptIsChineseOrJapanese =
+ loc.Script().EqualTo("Hans") || loc.Script().EqualTo("Hant") ||
+ loc.Script().EqualTo("Jpan") || loc.Script().EqualTo("Hrkt");
+ }
+ mCurrentWordLanguage = aHyphenationLanguage;
+ }
+}
+
+nsresult nsLineBreaker::AppendInvisibleWhitespace(uint32_t aFlags) {
+ nsresult rv = FlushCurrentWord();
+ if (NS_FAILED(rv)) return rv;
+
+ bool isBreakableSpace = !(aFlags & BREAK_SUPPRESS_INSIDE);
+ if (mAfterBreakableSpace && !isBreakableSpace) {
+ mBreakHere = true;
+ }
+ mAfterBreakableSpace = isBreakableSpace;
+ mWordContinuation = false;
+ return NS_OK;
+}
+
+nsresult nsLineBreaker::Reset(bool* aTrailingBreak) {
+ nsresult rv = FlushCurrentWord();
+ if (NS_FAILED(rv)) return rv;
+
+ *aTrailingBreak = mBreakHere || mAfterBreakableSpace;
+ mBreakHere = false;
+ mAfterBreakableSpace = false;
+ return NS_OK;
+}