93 lines
3.5 KiB
C++
93 lines
3.5 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is nsDiskCacheBlockFile.h, released
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* April 12, 2001.
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 2001
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Gordon Sheridan <gordon@netscape.com>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef _nsDiskCacheBlockFile_h_
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#define _nsDiskCacheBlockFile_h_
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#include "nsILocalFile.h"
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#include "nspr.h"
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const unsigned short kBitMapBytes = 4096;
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/******************************************************************************
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* nsDiskCacheBlockFile
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*
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* The structure of a cache block file is a 4096 bytes bit map, followed by
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* some number of blocks of mBlockSize. The creator of a
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* nsDiskCacheBlockFile object must provide the block size for a given file.
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*
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*****************************************************************************/
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class nsDiskCacheBlockFile {
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public:
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nsDiskCacheBlockFile()
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: mFD(nsnull)
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, mBlockSize(0)
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, mEndOfFile(0)
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, mBitMap(nsnull)
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, mBitMapDirty(PR_FALSE)
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{}
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~nsDiskCacheBlockFile() { (void) Close(PR_TRUE); }
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nsresult Open( nsILocalFile * blockFile, PRUint32 blockSize);
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nsresult Close(PRBool flush);
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nsresult Trim();
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PRInt32 AllocateBlocks( PRInt32 numBlocks);
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nsresult DeallocateBlocks( PRInt32 startBlock, PRInt32 numBlocks);
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nsresult WriteBlocks( void * buffer, PRInt32 startBlock, PRInt32 numBlocks);
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nsresult ReadBlocks( void * buffer, PRInt32 startBlock, PRInt32 numBlocks);
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private:
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nsresult FlushBitMap();
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nsresult ValidateFile(); // called by Open()
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nsresult VerifyAllocation( PRInt32 startBlock, PRInt32 numBLocks);
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PRInt32 LastBlock();
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/**
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* Data members
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*/
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PRFileDesc * mFD;
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PRUint32 mBlockSize;
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PRUint32 mEndOfFile;
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PRUint8 * mBitMap; // XXX future: array of bit map blocks
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PRBool mBitMapDirty;
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};
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#endif // _nsDiskCacheBlockFile_h_
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