gecko/gfx/thebes/gfxTextRunWordCache.h

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 * The Original Code is Mozilla Foundation code.
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 * The Initial Developer of the Original Code is Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2006
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 * Contributor(s):
 *   Vladimir Vukicevic <vladimir@pobox.com>
 *   Ehsan Akhgari <ehsan.akhgari@gmail.com>
 *   Jonathan Kew <jfkthame@gmail.com>
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#ifndef GFX_TEXT_RUN_WORD_CACHE_H
#define GFX_TEXT_RUN_WORD_CACHE_H

#include "gfxFont.h"

/**
 * Cache individual "words" (strings delimited by white-space or white-space-like
 * characters that don't involve kerning or ligatures) in textruns.
  */
class THEBES_API gfxTextRunWordCache {
public:
    enum {
      TEXT_IN_CACHE = 0x10000000,

      /**
       * nsTextFrameThebes sets these, but they're defined here rather than in
       * nsTextFrameUtils.h because the cache also needs to check the _INCOMING flag
       */
      TEXT_TRAILING_ARABICCHAR = 0x20000000,
      /**
       * When set, the previous character for this textrun was an Arabic
       * character.  This is used for the context detection necessary for
       * bidi.numeral implementation.
       */
      TEXT_INCOMING_ARABICCHAR = 0x40000000,

      TEXT_UNUSED_FLAGS = 0x80000000
    };

    /**
     * Create a textrun using cached words.
     * Invalid characters (see gfxFontGroup::IsInvalidChar) will be automatically
     * treated as invisible missing.
     * @param aFlags the flag TEXT_IS_ASCII must be set by the caller,
     * if applicable; TEXT_IN_CACHE is added if we have a reference to
     * the textrun in the cache and RemoveTextRun must be called when the
     * textrun dies.
     */
    static gfxTextRun *MakeTextRun(const PRUnichar *aText, PRUint32 aLength,
                                   gfxFontGroup *aFontGroup,
                                   const gfxFontGroup::Parameters *aParams,
                                   PRUint32 aFlags);
    /**
     * Create a textrun using cached words.
     * Invalid characters (see gfxFontGroup::IsInvalidChar) will be automatically
     * treated as invisible missing.
     * @param aFlags the flag TEXT_IS_ASCII must be set by the caller,
     * if applicable; TEXT_IN_CACHE is added if we have a reference to
     * the textrun in the cache and RemoveTextRun must be called when the
     * textrun dies.
     */
    static gfxTextRun *MakeTextRun(const PRUint8 *aText, PRUint32 aLength,
                                   gfxFontGroup *aFontGroup,
                                   const gfxFontGroup::Parameters *aParams,
                                   PRUint32 aFlags);

    /**
     * Remove a textrun from the cache. This must be called before aTextRun
     * is deleted! The text in the textrun must still be valid.
     */
    static void RemoveTextRun(gfxTextRun *aTextRun);

    /**
     * Flush the textrun cache. This must be called if a configuration
     * change that would affect textruns is applied.
     */
    static void Flush();

    /**
     * If aTotal is NULL, just clears the TEXT_RUN_MEMORY_ACCOUNTED flag
     * on each textRun found.
     * If aTotal is non-NULL, adds the storage used for each textRun to the
     * total, and sets the TEXT_RUN_MEMORY_ACCOUNTED flag to avoid double-
     * accounting. (Runs with this flag already set will be skipped.)
     */
    static void ComputeStorage(PRUint64 *aTotal);

protected:
    friend class gfxPlatform;

    static nsresult Init();
    static void Shutdown();
};

#endif /* GFX_TEXT_RUN_WORD_CACHE_H */