reactos/tools/rbuild/filesupportcode.cpp

   1 /*
   2  * Copyright (C) 2005 Casper S. Hornstrup
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18 #include "pch.h"
  19 #include <assert.h>
  20
  21 #include "rbuild.h"
  22
  23 using std::string;
  24
  25 /* static */ void
  26 FileSupportCode::WriteIfChanged ( char* outbuf,
  27                                   string filename )
  28 {
  29         FILE* out;
  30         unsigned int end;
  31         char* cmpbuf;
  32         unsigned int stat;
  33
  34         out = fopen ( filename.c_str (), "rb" );
  35         if ( out == NULL )
  36         {
  37                 out = fopen ( filename.c_str (), "wb" );
  38                 if ( out == NULL )
  39                         throw AccessDeniedException ( filename );
  40                 fputs ( outbuf, out );
  41                 fclose ( out );
  42                 return;
  43         }
  44
  45         fseek ( out, 0, SEEK_END );
  46         end = ftell ( out );
  47         cmpbuf = (char*) malloc ( end );
  48         if ( cmpbuf == NULL )
  49         {
  50                 fclose ( out );
  51                 throw OutOfMemoryException ();
  52         }
  53
  54         fseek ( out, 0, SEEK_SET );
  55         stat = fread ( cmpbuf, 1, end, out );
  56         if ( stat != end )
  57         {
  58                 free ( cmpbuf );
  59                 fclose ( out );
  60                 throw AccessDeniedException ( filename );
  61         }
  62         if ( end == strlen ( outbuf ) && memcmp ( cmpbuf, outbuf, end ) == 0 )
  63         {
  64                 free ( cmpbuf );
  65                 fclose ( out );
  66                 return;
  67         }
  68
  69         free ( cmpbuf );
  70         fclose ( out );
  71         out = fopen ( filename.c_str (), "wb" );
  72         if ( out == NULL )
  73         {
  74                 throw AccessDeniedException ( filename );
  75         }
  76
  77         stat = fwrite ( outbuf, 1, strlen ( outbuf ), out);
  78         if ( strlen ( outbuf ) != stat )
  79         {
  80                 fclose ( out );
  81                 throw AccessDeniedException ( filename );
  82         }
  83
  84         fclose ( out );
  85 }