libs/pbd/epa.cc

   1 /*
   2     Copyright (C) 2010 Paul Davis
   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 */
  19
  20 #include <cstdlib>
  21 #include <iostream>
  22
  23 #include "pbd/epa.h"
  24 #include "pbd/strsplit.h"
  25
  26 extern char** environ;
  27
  28 using namespace PBD;
  29 using namespace std;
  30
  31 EnvironmentalProtectionAgency* EnvironmentalProtectionAgency::_global_epa = 0;
  32
  33 EnvironmentalProtectionAgency::EnvironmentalProtectionAgency (bool arm, const std::string& envname)
  34         : _armed (arm)
  35         , _envname (envname)
  36 {
  37         if (_armed) {
  38                 save ();
  39         }
  40 }
  41
  42 EnvironmentalProtectionAgency::~EnvironmentalProtectionAgency()
  43 {
  44         if (_armed) {
  45                 restore ();
  46         }
  47 }
  48
  49 void
  50 EnvironmentalProtectionAgency::arm ()
  51 {
  52         _armed = true;
  53 }
  54
  55 void
  56 EnvironmentalProtectionAgency::save ()
  57 {
  58         e.clear ();
  59
  60         if (!_envname.empty()) {
  61
  62                 /* fetch environment from named environment variable, rather than "environ"
  63                  */
  64
  65                 const char* estr = getenv (_envname.c_str());
  66
  67                 if (!estr) {
  68                         return;
  69                 }
  70
  71                 /* parse line by line, and save into "e"
  72                  */
  73
  74                 vector<string> lines;
  75                 split (estr, lines, '\n');
  76
  77                 for (vector<string>::iterator i = lines.begin(); i != lines.end(); ++i) {
  78
  79                         string estring = *i;
  80                         string::size_type equal = estring.find_first_of ('=');
  81
  82                         if (equal == string::npos) {
  83                                 /* say what? an environ value without = ? */
  84                                 continue;
  85                         }
  86
  87                         string before = estring.substr (0, equal);
  88                         string after = estring.substr (equal+1);
  89
  90                         e.insert (pair<string,string>(before,after));
  91                 }
  92
  93         } else {
  94
  95                 /* fetch environment from "environ"
  96                  */
  97
  98                 for (size_t i = 0; environ[i]; ++i) {
  99
 100                         string estring = environ[i];
 101                         string::size_type equal = estring.find_first_of ('=');
 102
 103                         if (equal == string::npos) {
 104                                 /* say what? an environ value without = ? */
 105                                 continue;
 106                         }
 107
 108                         string before = estring.substr (0, equal);
 109                         string after = estring.substr (equal+1);
 110
 111                         e.insert (pair<string,string>(before,after));
 112                 }
 113         }
 114 }
 115 void
 116 EnvironmentalProtectionAgency::restore () const
 117 {
 118         for (map<string,string>::const_iterator i = e.begin(); i != e.end(); ++i) {
 119                 setenv (i->first.c_str(), i->second.c_str(), 1);
 120         }
 121 }