summaryrefslogtreecommitdiff
path: root/Source/cmGeneratedFileStream.cxx
blob: 6fe889df733125c7d29f7168c2245bfdd215b59d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
/*=========================================================================

  Program:   CMake - Cross-Platform Makefile Generator
  Module:    $RCSfile$
  Language:  C++
  Date:      $Date$
  Version:   $Revision$

  Copyright (c) 2002 Kitware, Inc., Insight Consortium.  All rights reserved.
  See Copyright.txt or http://www.cmake.org/HTML/Copyright.html for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#include "cmGeneratedFileStream.h"

#include "cmSystemTools.h"

// Includes needed for implementation of RenameFile.  This is not in
// system tools because it is not implemented robustly enough to move
// files across directories.
#ifdef _WIN32
# include <windows.h>
# include <sys/stat.h>
#endif

//----------------------------------------------------------------------------
cmGeneratedFileStream::cmGeneratedFileStream(const char* name,
                                             bool copy_if_different,
                                             bool quiet):
  cmGeneratedFileStreamBase(name, copy_if_different),
  std::ofstream(m_TempName.c_str())
{
  // Check if the file opened.
  if(!*this && !quiet)
    {
    cmSystemTools::Error("Cannot open file for write: ", m_TempName.c_str());
    cmSystemTools::ReportLastSystemError("");
    }
}

//----------------------------------------------------------------------------
cmGeneratedFileStream::~cmGeneratedFileStream()
{
  // This is the first destructor called.  Check the status of the
  // stream and give the information to the private base.  Next the
  // stream will be destroyed which will close the temporary file.
  // Finally the base destructor will be called to replace the
  // destination file.
  m_Okay = *this;
}

//----------------------------------------------------------------------------
cmGeneratedFileStreamBase::cmGeneratedFileStreamBase(const char* name,
                                                     bool copy_if_different):
  m_Name(name),
  m_TempName(name),
  m_CopyIfDifferent(copy_if_different),
  m_Okay(false)
{
  // Create the name of the temporary file.
  m_TempName += ".tmp";

  // Make sure the temporary file that will be used is not present.
  cmSystemTools::RemoveFile(m_TempName.c_str());
}

//----------------------------------------------------------------------------
cmGeneratedFileStreamBase::~cmGeneratedFileStreamBase()
{
  // Only consider replacing the destination file if no error
  // occurred.
  if(m_Okay &&
     (!m_CopyIfDifferent ||
      cmSystemTools::FilesDiffer(m_TempName.c_str(), m_Name.c_str())))
    {
    // The destination is to be replaced.  Rename the temporary to the
    // destination atomically.
    this->RenameFile(m_TempName.c_str(), m_Name.c_str());
    }
  else
    {
    // The destination was not replaced.  Just delete the temporary
    // file.
    cmSystemTools::RemoveFile(m_TempName.c_str());
    }
}

//----------------------------------------------------------------------------
int cmGeneratedFileStreamBase::RenameFile(const char* oldname,
                                          const char* newname)
{
#ifdef _WIN32
  /* On Windows the move functions will not replace existing files.
     Check if the destination exists.  */
  struct stat newFile;
  if(stat(newname, &newFile) == 0)
    {
    /* The destination exists.  We have to replace it carefully.  The
       MoveFileEx function does what we need but is not available on
       Win9x.  */
    OSVERSIONINFO osv;
    DWORD attrs;

    /* Make sure the destination is not read only.  */
    attrs = GetFileAttributes(newname);
    if(attrs & FILE_ATTRIBUTE_READONLY)
      {
      SetFileAttributes(newname, attrs & ~FILE_ATTRIBUTE_READONLY);
      }

    /* Check the windows version number.  */
    osv.dwOSVersionInfoSize = sizeof(osv);
    GetVersionEx(&osv);
    if(osv.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS)
      {
      /* This is Win9x.  There is no MoveFileEx implementation.  We
         cannot quite rename the file atomically.  Just delete the
         destination and then move the file.  */
      DeleteFile(newname);
      return MoveFile(oldname, newname);
      }
    else
      {
      /* This is not Win9x.  Use the MoveFileEx implementation.  */
      return MoveFileEx(oldname, newname, MOVEFILE_REPLACE_EXISTING);
      }
    }
  else
    {
    /* The destination does not exist.  Just move the file.  */
    return MoveFile(oldname, newname);
    }
#else
  /* On UNIX we have an OS-provided call to do this atomically.  */
  return rename(oldname, newname) == 0;
#endif
}