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a89752dfe7
git-svn-id: http://encfs.googlecode.com/svn/trunk@121 db9cf616-1c43-0410-9cb8-a902689de0d6
70 lines
2.2 KiB
C++
70 lines
2.2 KiB
C++
/*****************************************************************************
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* Author: Valient Gough <vgough@pobox.com>
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*
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*****************************************************************************
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* Copyright (c) 2004, Valient Gough
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*
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* This program is free software: you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or (at your
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* option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
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* for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _BlockFileIO_incl_
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#define _BlockFileIO_incl_
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#include "fs/FileIO.h"
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#include "fs/FSConfig.h"
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namespace encfs {
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/*
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Implements block scatter / gather interface. Requires derived classes to
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implement readOneBlock() / writeOneBlock() at a minimum.
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When a partial block write is requested it will be turned into a read of
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the existing block, merge with the write request, and a write of the full
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block.
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*/
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class BlockFileIO : public FileIO {
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public:
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BlockFileIO(int blockSize, const FSConfigPtr &cfg);
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virtual ~BlockFileIO();
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// implemented in terms of blocks.
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virtual ssize_t read(const IORequest &req) const;
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virtual bool write(const IORequest &req);
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virtual int blockSize() const;
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protected:
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int blockTruncate(off_t size, FileIO *base);
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void padFile(off_t oldSize, off_t newSize, bool forceWrite);
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// same as read(), except that the request.offset field is guarenteed to be
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// block aligned, and the request size will not be larger then 1 block.
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virtual ssize_t readOneBlock(const IORequest &req) const = 0;
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virtual bool writeOneBlock(const IORequest &req) = 0;
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ssize_t cacheReadOneBlock(const IORequest &req) const;
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bool cacheWriteOneBlock(const IORequest &req);
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int _blockSize;
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bool _allowHoles;
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// cache last block for speed...
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mutable IORequest _cache;
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};
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} // namespace encfs
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#endif
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