gfx/thebes/gfxTextRunCache.h

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  * ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is Mozilla Foundation code.
  16  *
  17  * The Initial Developer of the Original Code is Mozilla Foundation.
  18  * Portions created by the Initial Developer are Copyright (C) 2006
  19  * the Initial Developer. All Rights Reserved.
  20  *
  21  * Contributor(s):
  22  *   Vladimir Vukicevic <vladimir@pobox.com>
  23  *
  24  * Alternatively, the contents of this file may be used under the terms of
  25  * either the GNU General Public License Version 2 or later (the "GPL"), or
  26  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  27  * in which case the provisions of the GPL or the LGPL are applicable instead
  28  * of those above. If you wish to allow use of your version of this file only
  29  * under the terms of either the GPL or the LGPL, and not to allow others to
  30  * use your version of this file under the terms of the MPL, indicate your
  31  * decision by deleting the provisions above and replace them with the notice
  32  * and other provisions required by the GPL or the LGPL. If you do not delete
  33  * the provisions above, a recipient may use your version of this file under
  34  * the terms of any one of the MPL, the GPL or the LGPL.
  35  *
  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #ifndef GFX_TEXT_RUN_CACHE_H
  39 #define GFX_TEXT_RUN_CACHE_H
  40
  41 #include "gfxFont.h"
  42
  43 /**
  44  * A simple textrun cache for textruns that do not carry state
  45  * (e.g., actual or potential linebreaks) and do not need complex initialization.
  46  * The lifetimes of these textruns are managed by the cache (they are auto-expired
  47  * after a certain period of time).
  48  */
  49 class THEBES_API gfxTextRunCache {
  50 public:
  51     /**
  52      * Get a textrun for the given text, using a global cache. The textrun
  53      * must be released via ReleaseTextRun, not deleted.
  54      * Do not set any state in the textrun (e.g. actual or potential linebreaks).
  55      * Flags IS_8BIT and IS_ASCII are automatically set appropriately.
  56      * Flag IS_PERSISTENT must NOT be set unless aText is guaranteed to live
  57      * forever.
  58      * The string can contain any characters, invalid ones will be stripped
  59      * properly.
  60      */
  61     static gfxTextRun *MakeTextRun(const PRUnichar *aText, PRUint32 aLength,
  62                                    gfxFontGroup *aFontGroup,
  63                                    gfxContext *aRefContext,
  64                                    PRUint32 aAppUnitsPerDevUnit,
  65                                    PRUint32 aFlags);
  66
  67     /**
  68      * As above, but allows a full Parameters object to be passed in.
  69      */
  70     static gfxTextRun *MakeTextRun(const PRUnichar *aText, PRUint32 aLength,
  71                                    gfxFontGroup *aFontGroup,
  72                                    const gfxTextRunFactory::Parameters* aParams,
  73                                    PRUint32 aFlags);
  74
  75     /**
  76      * Get a textrun for the given text, using a global cache. The textrun
  77      * must be released via ReleaseTextRun, not deleted.
  78      * Do not set any state in the textrun (e.g. actual or potential linebreaks).
  79      * Flags IS_8BIT, IS_ASCII and HAS_SURROGATES are automatically set
  80      * appropriately.
  81      * Flag IS_PERSISTENT must NOT be set unless aText is guaranteed to live
  82      * forever.
  83      * The string can contain any characters, invalid ones will be stripped
  84      * properly.
  85      */
  86     static gfxTextRun *MakeTextRun(const PRUint8 *aText, PRUint32 aLength,
  87                                    gfxFontGroup *aFontGroup,
  88                                    gfxContext *aRefContext,
  89                                    PRUint32 aAppUnitsPerDevUnit,
  90                                    PRUint32 aFlags);
  91
  92     /**
  93      * Release a previously acquired textrun. Consider using AutoTextRun
  94      * instead of calling this.
  95      */
  96     static void ReleaseTextRun(gfxTextRun *aTextRun);
  97
  98     class AutoTextRun {
  99     public:
 100         AutoTextRun(gfxTextRun *aTextRun) : mTextRun(aTextRun) {}
 101         AutoTextRun() : mTextRun(nsnull) {}
 102         AutoTextRun& operator=(gfxTextRun *aTextRun) {
 103             gfxTextRunCache::ReleaseTextRun(mTextRun);
 104             mTextRun = aTextRun;
 105             return *this;
 106         }
 107         ~AutoTextRun() {
 108             gfxTextRunCache::ReleaseTextRun(mTextRun);
 109         }
 110         gfxTextRun *get() { return mTextRun; }
 111         gfxTextRun *operator->() { return mTextRun; }
 112     private:
 113         gfxTextRun *mTextRun;
 114     };
 115
 116 protected:
 117     friend class gfxPlatform;
 118
 119     static nsresult Init();
 120     static void Shutdown();
 121 };
 122
 123 #endif /* GFX_TEXT_RUN_CACHE_H */