139 lines
3.5 KiB
C++
139 lines
3.5 KiB
C++
/*=========================================================================
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Program: Insight Segmentation & Registration Toolkit
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Module: $RCSfile$
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Language: C++
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Date: $Date$
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Version: $Revision$
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Copyright (c) 2002 Insight Consortium. All rights reserved.
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See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
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This software is distributed WITHOUT ANY WARRANTY; without even
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the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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PURPOSE. See the above copyright notices for more information.
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=========================================================================*/
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#ifndef cmGeneratedFileStream_h
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#define cmGeneratedFileStream_h
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#include "cmStandardIncludes.h"
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/** \class cmGeneratedFileStream
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* \brief Output stream for generated files that does copy-if-different.
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*
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* Many files generated by CMake don't change each time they are generated.
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* This class can be used in place of std::ofstream to open a file and
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* write output to it. The class will automatically write output to a
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* temporary file and copy it over an existing file only if the generated
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* file has changed.
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*/
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class cmGeneratedFileStream
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{
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public:
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/**
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* The constructor takes the name of the file to be generated. It
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* automatically generates a name for the temporary file.
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*/
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cmGeneratedFileStream(const char* name):
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m_Name(name),
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m_TempName(m_Name+".tmp"),
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m_Stream(m_TempName.c_str()),
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m_Copied(false),
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m_AlwaysCopy(false)
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{}
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/**
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* The destructor ensures that the file has been closed and copied if
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* it has changed.
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*/
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~cmGeneratedFileStream() { this->DoCopy(); }
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/**
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* Get the real output stream.
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*/
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std::ostream& GetStream() { return m_Stream; }
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/**
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* Allow a test for whether the file is open.
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*/
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operator bool() { return m_Stream.good(); }
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/**
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* Close the file stream. This will cause the copy-if-different to the
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* real file name to occur.
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*/
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void close() { this->DoCopy(); }
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/**
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* If always copy is true, then copy the file all the time without
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* checking for differences. The default is false.
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*/
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bool SetAlwaysCopy(bool v) { m_AlwaysCopy = v; return v;}
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private:
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/**
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* The name of the real file where output will be copied if it has changed.
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*/
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std::string m_Name;
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/**
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* The name of the temporary file.
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*/
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std::string m_TempName;
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/**
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* The real output stream used to write to the file.
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*/
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std::ofstream m_Stream;
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/**
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* Whether the temporary file has already been copied to the real file.
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*/
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bool m_Copied;
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/**
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* If always copy is true, then copy the file all the time without
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* checking for differences. The default is false.
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*/
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bool m_AlwaysCopy;
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/**
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* Closes the temporary file and does the copy-if-different to the
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* real file.
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*/
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void DoCopy()
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{
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if(!m_Copied)
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{
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m_Stream.close();
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if(m_AlwaysCopy)
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{
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cmSystemTools::cmCopyFile(m_TempName.c_str(), m_Name.c_str());
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}
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else
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{
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cmSystemTools::CopyFileIfDifferent(m_TempName.c_str(),
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m_Name.c_str());
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}
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cmSystemTools::RemoveFile(m_TempName.c_str());
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m_Copied = true;
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}
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}
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};
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/**
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* Allow a cmGeneratedFileStream to be used just as a real std::ostream
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* would be.
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*/
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template <class T>
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std::ostream& operator << (cmGeneratedFileStream& l, const T& r)
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{
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std::ostream& os = l.GetStream();
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os << r;
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return os;
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}
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#endif
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