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nsCacheMetaData.h
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00001 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
00002  *
00003  * ***** BEGIN LICENSE BLOCK *****
00004  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
00005  *
00006  * The contents of this file are subject to the Mozilla Public License Version
00007  * 1.1 (the "License"); you may not use this file except in compliance with
00008  * the License. You may obtain a copy of the License at
00009  * http://www.mozilla.org/MPL/
00010  *
00011  * Software distributed under the License is distributed on an "AS IS" basis,
00012  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00013  * for the specific language governing rights and limitations under the
00014  * License.
00015  *
00016  * The Original Code is nsCacheMetaData.h, released
00017  * February 22, 2001.
00018  *
00019  * The Initial Developer of the Original Code is
00020  * Netscape Communications Corporation.
00021  * Portions created by the Initial Developer are Copyright (C) 2001
00022  * the Initial Developer. All Rights Reserved.
00023  *
00024  * Contributor(s):
00025  *   Gordon Sheridan <gordon@netscape.com>
00026  *
00027  * Alternatively, the contents of this file may be used under the terms of
00028  * either the GNU General Public License Version 2 or later (the "GPL"), or
00029  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00030  * in which case the provisions of the GPL or the LGPL are applicable instead
00031  * of those above. If you wish to allow use of your version of this file only
00032  * under the terms of either the GPL or the LGPL, and not to allow others to
00033  * use your version of this file under the terms of the MPL, indicate your
00034  * decision by deleting the provisions above and replace them with the notice
00035  * and other provisions required by the GPL or the LGPL. If you do not delete
00036  * the provisions above, a recipient may use your version of this file under
00037  * the terms of any one of the MPL, the GPL or the LGPL.
00038  *
00039  * ***** END LICENSE BLOCK ***** */
00040 
00041 #ifndef _nsCacheMetaData_h_
00042 #define _nsCacheMetaData_h_
00043 
00044 #include "nspr.h"
00045 #include "pldhash.h"
00046 #include "nscore.h"
00047 #include "nsIAtom.h"
00048 
00049 class nsICacheMetaDataVisitor;
00050 
00051 class nsCacheMetaData {
00052 public:
00053     nsCacheMetaData();
00054     ~nsCacheMetaData()  { Clear(); }
00055 
00056     void                  Clear();
00057     PRBool                IsEmpty() { return (mData == nsnull); }
00058 
00059     const char *          GetElement(const char * key);
00060 
00061     nsresult              SetElement(const char * key,
00062                                      const char * value);
00063 
00064     PRUint32              Size(void) { return mMetaSize; }
00065 
00066     nsresult              FlattenMetaData(char * buffer, PRUint32 bufSize);
00067 
00068     nsresult              UnflattenMetaData(const char * buffer, PRUint32 bufSize);
00069 
00070     nsresult              VisitElements(nsICacheMetaDataVisitor * visitor);
00071 
00072 private:
00073 
00074     struct MetaElement
00075     {
00076         struct MetaElement * mNext;
00077         nsCOMPtr<nsIAtom>    mKey;
00078         char                 mValue[1]; // actually, bigger than 1
00079 
00080         // MetaElement and mValue are allocated together via:
00081         void *operator new(size_t size,
00082                            const char *value,
00083                            PRUint32 valueSize) CPP_THROW_NEW;
00084     };
00085 
00086     MetaElement * mData;
00087     PRUint32      mMetaSize;
00088 };
00089 
00090 #endif // _nsCacheMetaData_h