import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

dom/base/nsLineBreaker.cpp

@@ -0,0 +1,498 @@
+/* -*- 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 "nsILineBreaker.h"
+#include "gfxTextRun.h" // for the gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_* values
+#include "nsHyphenationManager.h"
+#include "nsHyphenator.h"
+#include "mozilla/gfx/2D.h"
+
+nsLineBreaker::nsLineBreaker()
+  : mCurrentWordLanguage(nullptr),
+    mCurrentWordContainsMixedLang(false),
+    mCurrentWordContainsComplexChar(false),
+    mAfterBreakableSpace(false), mBreakHere(false),
+    mWordBreak(nsILineBreaker::kWordBreak_Normal)
+{
+}
+
+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 start
+  // of the word.
+  // The only space character a word can contain is NBSP.
+  bool capitalizeNextChar = true;
+  for (uint32_t i = 0; i < aLength; ++i) {
+    uint32_t ch = aWord[i];
+    if (capitalizeNextChar) {
+      if (NS_IS_HIGH_SURROGATE(ch) && i + 1 < aLength &&
+          NS_IS_LOW_SURROGATE(aWord[i + 1])) {
+        ch = SURROGATE_TO_UCS4(ch, aWord[i + 1]);
+      }
+      if (nsContentUtils::IsAlphanumeric(ch)) {
+        aCapitalization[i] = true;
+        capitalizeNextChar = false;
+      }
+      if (!IS_IN_BMP(ch)) {
+        ++i;
+      }
+    }
+    if (ch == 0xA0 /*NBSP*/) {
+      capitalizeNextChar = true;
+    }
+  }
+}
+
+nsresult
+nsLineBreaker::FlushCurrentWord()
+{
+  uint32_t length = mCurrentWord.Length();
+  AutoTArray<uint8_t,4000> breakState;
+  if (!breakState.AppendElements(length))
+    return NS_ERROR_OUT_OF_MEMORY;
+  
+  nsTArray<bool> capitalizationState;
+
+  if (!mCurrentWordContainsComplexChar) {
+    // For break-strict set everything internal to "break", otherwise
+    // to "no break"!
+    memset(breakState.Elements(),
+           mWordBreak == nsILineBreaker::kWordBreak_BreakAll ?
+             gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NORMAL :
+             gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NONE,
+           length*sizeof(uint8_t));
+  } else {
+    nsContentUtils::LineBreaker()->
+      GetJISx4051Breaks(mCurrentWord.Elements(), length, mWordBreak,
+                        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());
+    }
+  }
+
+  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 (ti->mFlags & BREAK_NEED_CAPITALIZATION) {
+        if (capitalizationState.Length() == 0) {
+          if (!capitalizationState.AppendElements(length))
+            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;
+  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(nsIAtom* 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))
+      return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  bool noCapitalizationNeeded = true;
+  nsTArray<bool> capitalizationState;
+  if (aSink && (aFlags & BREAK_NEED_CAPITALIZATION)) {
+    if (!capitalizationState.AppendElements(aLength))
+      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 == nsILineBreaker::kWordBreak_BreakAll)  ?
+          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 (wordHasComplexChar) {
+            // Save current start-of-word state because GetJISx4051Breaks will
+            // set it to false
+            uint8_t currentStart = breakState[wordStart];
+            nsContentUtils::LineBreaker()->
+              GetJISx4051Breaks(aText + wordStart, offset - wordStart,
+                                mWordBreak,
+                                breakState.Elements() + wordStart);
+            breakState[wordStart] = currentStart;
+          }
+          if (hyphenator) {
+            FindHyphenationPoints(hyphenator,
+                                  aText + wordStart, aText + offset,
+                                  breakState.Elements() + wordStart);
+          }
+        }
+        if (!noCapitalizationNeeded) {
+          SetupCapitalization(aText + wordStart, offset - wordStart,
+                              capitalizationState.Elements() + wordStart);
+        }
+      }
+      wordHasComplexChar = 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(nsIAtom* 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))
+      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 == nsILineBreaker::kWordBreak_BreakAll) ?
+          gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NORMAL :
+          gfxTextRun::CompressedGlyph::FLAG_BREAK_TYPE_NONE;
+    }
+    mBreakHere = false;
+    mAfterBreakableSpace = isBreakableSpace;
+
+    if (isSpace) {
+      if (offset > wordStart && wordHasComplexChar) {
+        if (aSink && !(aFlags & BREAK_SUPPRESS_INSIDE)) {
+          // Save current start-of-word state because GetJISx4051Breaks will
+          // set it to false
+          uint8_t currentStart = breakState[wordStart];
+          nsContentUtils::LineBreaker()->
+            GetJISx4051Breaks(aText + wordStart, offset - wordStart,
+                              mWordBreak,
+                              breakState.Elements() + wordStart);
+          breakState[wordStart] = currentStart;
+        }
+        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(nsIAtom *aHyphenationLanguage)
+{
+  if (mCurrentWordLanguage && mCurrentWordLanguage != aHyphenationLanguage) {
+    mCurrentWordContainsMixedLang = true;
+  } else {
+    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;
+  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;
+}