The Tor Browser: content/base/public/nsLineBreaker.h@6474c204b198 (annotated)

content/base/public/nsLineBreaker.h@6474c204b198 (annotated)

content/base/public/nsLineBreaker.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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/. */
 #ifndef NSLINEBREAKER_H_
 #define NSLINEBREAKER_H_
 #include "nsString.h"
 #include "nsTArray.h"
 #include "nsILineBreaker.h"
 class nsIAtom;
 class nsHyphenator;
 /**
  * A receiver of line break data.
  */
 class nsILineBreakSink {
 public:
   /**
    * Sets the break data for a substring of the associated text chunk.
    * One or more of these calls will be performed; the union of all substrings
    * will cover the entire text chunk. Substrings may overlap (i.e., we may
    * set the break-before state of a character more than once).
    * @param aBreakBefore the break-before states for the characters in the substring.
    * These are enum values from gfxTextRun::CompressedGlyph:
    *    FLAG_BREAK_TYPE_NONE     - no linebreak is allowed here
    *    FLAG_BREAK_TYPE_NORMAL   - a normal (whitespace) linebreak
    *    FLAG_BREAK_TYPE_HYPHEN   - a hyphenation point
    */
   virtual void SetBreaks(uint32_t aStart, uint32_t aLength, uint8_t* aBreakBefore) = 0;
   /**
    * Indicates which characters should be capitalized. Only called if
    * BREAK_NEED_CAPITALIZATION was requested.
    */
   virtual void SetCapitalization(uint32_t aStart, uint32_t aLength, bool* aCapitalize) = 0;
 };
 /**
  * A line-breaking state machine. You feed text into it via AppendText calls
  * and it computes the possible line breaks. Because break decisions can
  * require a lot of context, the breaks for a piece of text are sometimes not
  * known until later text has been seen (or all text ends). So breaks are
  * returned via a call to SetBreaks on the nsILineBreakSink object passed
  * with each text chunk, which might happen during the corresponding AppendText
  * call, or might happen during a later AppendText call or even a Reset()
  * call.
  *
  * The linebreak results MUST NOT depend on how the text is broken up
  * into AppendText calls.
  *
  * The current strategy is that we break the overall text into
  * whitespace-delimited "words". Then those words are passed to the nsILineBreaker
  * service for deeper analysis if they contain a "complex" character as described
  * below.
  *
  * This class also handles detection of which characters should be capitalized
  * for text-transform:capitalize. This is a good place to handle that because
  * we have all the context we need.
  */
 class nsLineBreaker {
 public:
   nsLineBreaker();
   ~nsLineBreaker();
   static inline bool IsSpace(char16_t u) { return NS_IsSpace(u); }
   static inline bool IsComplexASCIIChar(char16_t u)
   {
     return !((0x0030 <= u && u <= 0x0039) ||
              (0x0041 <= u && u <= 0x005A) ||
              (0x0061 <= u && u <= 0x007A) ||
              (0x000a == u));
   }
   static inline bool IsComplexChar(char16_t u)
   {
     return IsComplexASCIIChar(u) ||
            NS_NeedsPlatformNativeHandling(u) ||
            (0x1100 <= u && u <= 0x11ff) || // Hangul Jamo
            (0x2000 <= u && u <= 0x21ff) || // Punctuations and Symbols
            (0x2e80 <= u && u <= 0xd7ff) || // several CJK blocks
            (0xf900 <= u && u <= 0xfaff) || // CJK Compatibility Idographs
            (0xff00 <= u && u <= 0xffef);   // Halfwidth and Fullwidth Forms
   }
   // Break opportunities exist at the end of each run of breakable whitespace
   // (see IsSpace above). Break opportunities can also exist between pairs of
   // non-whitespace characters, as determined by nsILineBreaker. We pass a whitespace-
   // delimited word to nsILineBreaker if it contains at least one character
   // matching IsComplexChar.
   // We provide flags to control on a per-chunk basis where breaks are allowed.
   // At any character boundary, exactly one text chunk governs whether a
   // break is allowed at that boundary.
   //
   // We operate on text after whitespace processing has been applied, so
   // other characters (e.g. tabs and newlines) may have been converted to
   // spaces.
   /**
    * Flags passed with each chunk of text.
    */
   enum {
     /*
      * Do not introduce a break opportunity at the start of this chunk of text.
      */
     BREAK_SUPPRESS_INITIAL = 0x01,
     /**
      * Do not introduce a break opportunity in the interior of this chunk of text.
      * Also, whitespace in this chunk is treated as non-breakable.
      */
     BREAK_SUPPRESS_INSIDE = 0x02,
     /**
      * The sink currently is already set up to have no breaks in it;
      * if no breaks are possible, nsLineBreaker does not need to call
      * SetBreaks on it. This is useful when handling large quantities of
      * preformatted text; the textruns will never have any breaks set on them,
      * and there is no need to ever actually scan the text for breaks, except
      * at the end of textruns in case context is needed for following breakable
      * text.
      */
     BREAK_SKIP_SETTING_NO_BREAKS = 0x04,
     /**
      * We need to be notified of characters that should be capitalized
      * (as in text-transform:capitalize) in this chunk of text.
      */
     BREAK_NEED_CAPITALIZATION = 0x08,
     /**
      * Auto-hyphenation is enabled, so we need to get a hyphenator
      * (if available) and use it to find breakpoints.
      */
     BREAK_USE_AUTO_HYPHENATION = 0x10
   };
   /**
    * Append "invisible whitespace". This acts like whitespace, but there is
    * no actual text associated with it. Only the BREAK_SUPPRESS_INSIDE flag
    * is relevant here.
    */
   nsresult AppendInvisibleWhitespace(uint32_t aFlags);
   /**
    * Feed Unicode text into the linebreaker for analysis. aLength must be
    * nonzero.
    * @param aSink can be null if the breaks are not actually needed (we may
    * still be setting up state for later breaks)
    */
   nsresult AppendText(nsIAtom* aHyphenationLanguage, const char16_t* aText, uint32_t aLength,
                       uint32_t aFlags, nsILineBreakSink* aSink);
   /**
    * Feed 8-bit text into the linebreaker for analysis. aLength must be nonzero.
    * @param aSink can be null if the breaks are not actually needed (we may
    * still be setting up state for later breaks)
    */
   nsresult AppendText(nsIAtom* aHyphenationLanguage, const uint8_t* aText, uint32_t aLength,
                       uint32_t aFlags, nsILineBreakSink* aSink);
   /**
    * Reset all state. This means the current run has ended; any outstanding
    * calls through nsILineBreakSink are made, and all outstanding references to
    * nsILineBreakSink objects are dropped.
    * After this call, this linebreaker can be reused.
    * This must be called at least once between any call to AppendText() and
    * destroying the object.
    * @param aTrailingBreak this is set to true when there is a break opportunity
    * at the end of the text. This will normally only be declared true when there
    * is breakable whitespace at the end.
    */
   nsresult Reset(bool* aTrailingBreak);
   /*
    * Set word-break mode for linebreaker.  This is set by word-break property.
    * @param aMode is nsILineBreaker::kWordBreak_* value.
    */
   void SetWordBreak(uint8_t aMode) { mWordBreak = aMode; }
 private:
   // This is a list of text sources that make up the "current word" (i.e.,
   // run of text which does not contain any whitespace). All the mLengths
   // are are nonzero, these cannot overlap.
   struct TextItem {
     TextItem(nsILineBreakSink* aSink, uint32_t aSinkOffset, uint32_t aLength,
              uint32_t aFlags)
       : mSink(aSink), mSinkOffset(aSinkOffset), mLength(aLength), mFlags(aFlags) {}
     nsILineBreakSink* mSink;
     uint32_t          mSinkOffset;
     uint32_t          mLength;
     uint32_t          mFlags;
   };
   // State for the nonwhitespace "word" that started in previous text and hasn't
   // finished yet.
   // When the current word ends, this computes the linebreak opportunities
   // *inside* the word (excluding either end) and sets them through the
   // appropriate sink(s). Then we clear the current word state.
   nsresult FlushCurrentWord();
   void UpdateCurrentWordLanguage(nsIAtom *aHyphenationLanguage);
   void FindHyphenationPoints(nsHyphenator *aHyphenator,
                              const char16_t *aTextStart,
                              const char16_t *aTextLimit,
                              uint8_t *aBreakState);
   nsAutoTArray<char16_t,100> mCurrentWord;
   // All the items that contribute to mCurrentWord
   nsAutoTArray<TextItem,2>    mTextItems;
   nsIAtom*                    mCurrentWordLanguage;
   bool                        mCurrentWordContainsMixedLang;
   bool                        mCurrentWordContainsComplexChar;
   // True if the previous character was breakable whitespace
   bool                        mAfterBreakableSpace;
   // True if a break must be allowed at the current position because
   // a run of breakable whitespace ends here
   bool                        mBreakHere;
   // line break mode by "word-break" style
   uint8_t                     mWordBreak;
 };
 #endif /*NSLINEBREAKER_H_*/

The Tor Browser / annotate

content/base/public/nsLineBreaker.h@6474c204b198 (annotated)

content/base/public/nsLineBreaker.h