Source/cmGeneratedFileStream.h

   1 /*=========================================================================
   2
   3   Program:   CMake - Cross-Platform Makefile Generator
   4   Module:    $RCSfile: cmGeneratedFileStream.h,v $
   5   Language:  C++
   6   Date:      $Date: 2007-11-16 12:01:58 $
   7   Version:   $Revision: 1.23 $
   8
   9   Copyright (c) 2002 Kitware, Inc., Insight Consortium.  All rights reserved.
  10   See Copyright.txt or http://www.cmake.org/HTML/Copyright.html for details.
  11
  12      This software is distributed WITHOUT ANY WARRANTY; without even
  13      the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  14      PURPOSE.  See the above copyright notices for more information.
  15
  16 =========================================================================*/
  17 #ifndef cmGeneratedFileStream_h
  18 #define cmGeneratedFileStream_h
  19
  20 #include "cmStandardIncludes.h"
  21
  22 #if defined(__sgi) && !defined(__GNUC__)
  23 # pragma set woff 1375 /* base class destructor not virtual */
  24 #endif
  25
  26 // This is the first base class of cmGeneratedFileStream.  It will be
  27 // created before and destroyed after the ofstream portion and can
  28 // therefore be used to manage the temporary file.
  29 class cmGeneratedFileStreamBase
  30 {
  31 protected:
  32   // This constructor does not prepare the temporary file.  The open
  33   // method must be used.
  34   cmGeneratedFileStreamBase();
  35
  36   // This constructor prepares the temporary output file.
  37   cmGeneratedFileStreamBase(const char* name);
  38
  39   // The destructor renames the temporary output file to the real name.
  40   ~cmGeneratedFileStreamBase();
  41
  42   // Internal methods to handle the temporary file.  Open is always
  43   // called before the real stream is opened.  Close is always called
  44   // after the real stream is closed and Okay is set to whether the
  45   // real stream was still valid for writing when it was closed.
  46   void Open(const char* name);
  47   bool Close();
  48
  49   // Internal file replacement implementation.
  50   int RenameFile(const char* oldname, const char* newname);
  51
  52   // Internal file compression implementation.
  53   int CompressFile(const char* oldname, const char* newname);
  54
  55   // The name of the final destination file for the output.
  56   std::string Name;
  57
  58   // The name of the temporary file.
  59   std::string TempName;
  60
  61   // Whether to do a copy-if-different.
  62   bool CopyIfDifferent;
  63
  64   // Whether the real file stream was valid when it was closed.
  65   bool Okay;
  66
  67   // Whether the destionation file is compressed
  68   bool Compress;
  69
  70   // Whether the destionation file is compressed
  71   bool CompressExtraExtension;
  72 };
  73
  74 /** \class cmGeneratedFileStream
  75  * \brief Output stream for generated files.
  76  *
  77  * File generation should be atomic so that if CMake is killed then a
  78  * generated file is either the original version or the complete new
  79  * version.  This stream is used to make sure file generation is
  80  * atomic.  Optionally the output file is only replaced if its
  81  * contents have changed to prevent the file modification time from
  82  * being updated.
  83  */
  84 class cmGeneratedFileStream: private cmGeneratedFileStreamBase,
  85                              public std::ofstream
  86 {
  87 public:
  88   typedef std::ofstream Stream;
  89
  90   /**
  91    * This constructor prepares a default stream.  The open method must
  92    * be used before writing to the stream.
  93    */
  94   cmGeneratedFileStream();
  95
  96   /**
  97    * This constructor takes the name of the file to be generated.  It
  98    * automatically generates a name for the temporary file.  If the
  99    * file cannot be opened an error message is produced unless the
 100    * second argument is set to true.
 101    */
 102   cmGeneratedFileStream(const char* name, bool quiet=false);
 103
 104   /**
 105    * The destructor checks the stream status to be sure the temporary
 106    * file was successfully written before allowing the original to be
 107    * replaced.
 108    */
 109   ~cmGeneratedFileStream();
 110
 111   /**
 112    * Open an output file by name.  This should be used only with a
 113    * non-open stream.  It automatically generates a name for the
 114    * temporary file.  If the file cannot be opened an error message is
 115    * produced unless the second argument is set to true.
 116    */
 117   cmGeneratedFileStream& Open(const char* name, bool quiet=false,
 118     bool binaryFlag=false);
 119
 120   /**
 121    * Close the output file.  This should be used only with an open
 122    * stream.  The temporary file is atomically renamed to the
 123    * destionation file if the stream is still valid when this method
 124    * is called.
 125    */
 126   bool Close();
 127
 128   /**
 129    * Set whether copy-if-different is done.
 130    */
 131   void SetCopyIfDifferent(bool copy_if_different);
 132
 133   /**
 134    * Set whether compression is done.
 135    */
 136   void SetCompression(bool compression);
 137
 138   /**
 139    * Set whether compression has extra extension
 140    */
 141   void SetCompressionExtraExtension(bool ext);
 142
 143   /**
 144    * Set name of the file that will hold the actual output. This method allows
 145    * the output file to be changed during the use of cmGeneratedFileStream.
 146    */
 147   void SetName(const char* fname);
 148
 149 private:
 150   cmGeneratedFileStream(cmGeneratedFileStream const&); // not implemented
 151 };
 152
 153 #if defined(__sgi) && !defined(__GNUC__)
 154 # pragma reset woff 1375 /* base class destructor not virtual */
 155 #endif
 156
 157 #endif