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/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
file LICENSE.rst or https://cmake.org/licensing for details. */
#pragma once
#include "cmConfigure.h" // IWYU pragma: keep
#include <string>
#include "cmsys/FStream.hxx"
#include "cm_codecvt_Encoding.hxx"
// This is the first base class of cmGeneratedFileStream. It will be
// created before and destroyed after the ofstream portion and can
// therefore be used to manage the temporary file.
class cmGeneratedFileStreamBase
{
protected:
// This constructor does not prepare the temporary file. The open
// method must be used.
cmGeneratedFileStreamBase();
// This constructor prepares the temporary output file.
cmGeneratedFileStreamBase(std::string const& name);
// The destructor renames the temporary output file to the real name.
~cmGeneratedFileStreamBase();
// Internal methods to handle the temporary file. Open is always
// called before the real stream is opened. Close is always called
// after the real stream is closed and Okay is set to whether the
// real stream was still valid for writing when it was closed.
void Open(std::string const& name);
bool Close();
// Internal file replacement implementation.
int RenameFile(std::string const& oldname, std::string const& newname);
// Internal file compression implementation.
int CompressFile(std::string const& oldname, std::string const& newname);
// The name of the final destination file for the output.
std::string Name;
// The extension of the temporary file.
std::string TempExt;
// The name of the temporary file.
std::string TempName;
// Whether to do a copy-if-different.
bool CopyIfDifferent = false;
// Whether the real file stream was valid when it was closed.
bool Okay = false;
// Whether the destination file is compressed
bool Compress = false;
// Whether the destination file is compressed
bool CompressExtraExtension = true;
};
/** \class cmGeneratedFileStream
* \brief Output stream for generated files.
*
* File generation should be atomic so that if CMake is killed then a
* generated file is either the original version or the complete new
* version. This stream is used to make sure file generation is
* atomic. Optionally the output file is only replaced if its
* contents have changed to prevent the file modification time from
* being updated.
*/
class cmGeneratedFileStream
: private cmGeneratedFileStreamBase
, public cmsys::ofstream
{
public:
using Stream = cmsys::ofstream;
using Encoding = codecvt_Encoding;
/**
* This constructor prepares a default stream. The open method must
* be used before writing to the stream.
*/
cmGeneratedFileStream(codecvt_Encoding encoding = codecvt_Encoding::None);
/**
* This constructor takes the name of the file to be generated. It
* automatically generates a name for the temporary file. If the
* file cannot be opened an error message is produced unless the
* second argument is set to true.
*/
cmGeneratedFileStream(std::string const& name, bool quiet = false,
codecvt_Encoding encoding = codecvt_Encoding::None);
/**
* The destructor checks the stream status to be sure the temporary
* file was successfully written before allowing the original to be
* replaced.
*/
~cmGeneratedFileStream() override;
cmGeneratedFileStream(cmGeneratedFileStream const&) = delete;
/**
* Open an output file by name. This should be used only with a
* non-open stream. It automatically generates a name for the
* temporary file. If the file cannot be opened an error message is
* produced unless the second argument is set to true.
*/
cmGeneratedFileStream& Open(std::string const& name, bool quiet = false,
bool binaryFlag = false);
/**
* Close the output file. This should be used only with an open
* stream. The temporary file is atomically renamed to the
* destination file if the stream is still valid when this method
* is called.
*/
bool Close();
/**
* Set whether copy-if-different is done.
*/
void SetCopyIfDifferent(bool copy_if_different);
/**
* Set whether compression is done.
*/
void SetCompression(bool compression);
/**
* Set whether compression has extra extension
*/
void SetCompressionExtraExtension(bool ext);
/**
* Set name of the file that will hold the actual output. This method allows
* the output file to be changed during the use of cmGeneratedFileStream.
*/
void SetName(std::string const& fname);
/**
* Set set a custom temporary file extension used with 'Open'.
* This does not work if the file was opened by the constructor.
*/
void SetTempExt(std::string const& ext);
/**
* Get the name of the temporary file.
*/
std::string const& GetTempName() const { return this->TempName; }
/**
* Write a specific string using an alternate encoding.
* Afterward, the original encoding is restored.
*/
void WriteAltEncoding(std::string const& data, codecvt_Encoding encoding);
};
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