/* -*- 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/. */ #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); AutoTArray<char16_t,100> mCurrentWord; // All the items that contribute to mCurrentWord AutoTArray<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_*/