164 lines
4.2 KiB
C++
164 lines
4.2 KiB
C++
/*
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* Copyright (C) 2012 Intel Corporation
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) version 3.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#ifndef INCL_SYNCEVOLUTION_TMPFILE
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#define INCL_SYNCEVOLUTION_TMPFILE
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#include <stdexcept>
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#include <string>
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#include <pcrecpp.h>
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/**
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* Exception class for TmpFile.
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*/
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class TmpFileException : public std::runtime_error
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{
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public:
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TmpFileException(const std::string &what)
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: std::runtime_error(what)
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{ }
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};
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/**
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* Class for handling temporary files, either read/write access
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* or memory mapped. Optionally creates a pipe instead of a plain file.
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*
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* Reading is done mapping the plain file into memory (file) or simply
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* reading from the file descriptor (file or pipe).
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*
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* Closing and removing a mapped file is supported by calling close()
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* after map().
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*/
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class TmpFile
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{
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public:
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enum Type {
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FILE,
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PIPE
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};
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TmpFile();
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virtual ~TmpFile();
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/**
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* Create a temporary file or pipe.
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*/
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void create(Type type = FILE);
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/**
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* Map a view of file and optionally return pointer and/or size.
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*
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* File should already have a correct size.
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*
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* @param mapptr Pointer to variable for mapped pointer. (can be NULL)
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* @param mapsize Pointer to variable for mapped size. (can be NULL)
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*/
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void map(void **mapptr = 0, size_t *mapsize = 0);
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/**
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* Unmap a view of file.
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*/
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void unmap();
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/**
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* File descriptor, ready for reading from start of file or pipe
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* after create().
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*/
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int getFD() const { return m_fd; }
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/**
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* FILE by default, otherwise the value given to create().
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*/
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Type getType() const { return m_type; }
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/**
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* Returns amount of bytes not mapped into memory yet, zero if none.
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*/
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size_t moreData() const;
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/**
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* Remove the file. If the process crashes, the file will be removed,
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* but the process itself can still map and use the file content.
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*/
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void remove();
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/**
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* Remove and close the file.
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*
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* Calling this after map() will make the file disappear from
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* filesystem but the mapping will be valid until unmapped or
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* instance of this class is destroyed.
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*/
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void close();
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/**
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* Retrieve file name of the file.
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*
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* @return file name
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*/
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const std::string & filename() const
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{ return m_filename; }
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/**
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* Retrieve descriptor of the file.
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*
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* @return descriptor
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*/
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int fd()
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{ return m_fd; }
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/**
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* Size of the mapping.
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*
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* @return mapped size
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*/
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size_t size() const
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{ return m_mapsize; }
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/**
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* Pointer to the mapping.
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*
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* @return pointer to the mapping
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*/
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operator void *()
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{ return m_mapptr; }
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/**
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* @overload
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*/
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operator const void *() const
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{ return m_mapptr; }
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/**
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* Retrieve pcrecpp::StringPiece object for the mapped view.
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*
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* @return pcrecpp::StringPiece of the mapped view
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*/
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pcrecpp::StringPiece stringPiece();
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protected:
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Type m_type;
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int m_fd;
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void *m_mapptr;
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size_t m_mapsize;
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std::string m_filename;
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};
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#endif // INCL_SYNCEVOLUTION_TMPFILE
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