gdb/common/environ.h

   1 /* Header for environment manipulation library.
   2    Copyright (C) 1989-2017 Free Software Foundation, Inc.
   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 3 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, see <http://www.gnu.org/licenses/>.  */
  16
  17 #if !defined (ENVIRON_H)
  18 #define ENVIRON_H 1
  19
  20 #include <vector>
  21
  22 /* Class that represents the environment variables as seen by the
  23    inferior.  */
  24
  25 class gdb_environ
  26 {
  27 public:
  28   /* Regular constructor and destructor.  */
  29   gdb_environ ()
  30   {
  31     /* Make sure that the vector contains at least a NULL element.
  32        If/when we add more variables to it, NULL will always be the
  33        last element.  */
  34     m_environ_vector.push_back (NULL);
  35   }
  36
  37   ~gdb_environ ()
  38   {
  39     clear ();
  40   }
  41
  42   /* Move constructor.  */
  43   gdb_environ (gdb_environ &&e)
  44     : m_environ_vector (std::move (e.m_environ_vector))
  45   {
  46     /* Make sure that the moved-from vector is left at a valid
  47        state (only one NULL element).  */
  48     e.m_environ_vector.clear ();
  49     e.m_environ_vector.push_back (NULL);
  50   }
  51
  52   /* Move assignment.  */
  53   gdb_environ &operator= (gdb_environ &&e);
  54
  55   /* Create a gdb_environ object using the host's environment
  56      variables.  */
  57   static gdb_environ from_host_environ ();
  58
  59   /* Clear the environment variables stored in the object.  */
  60   void clear ();
  61
  62   /* Return the value in the environment for the variable VAR.  The
  63      returned pointer is only valid as long as the gdb_environ object
  64      is not modified.  */
  65   const char *get (const char *var) const;
  66
  67   /* Store VAR=VALUE in the environment.  */
  68   void set (const char *var, const char *value);
  69
  70   /* Unset VAR in environment.  */
  71   void unset (const char *var);
  72
  73   /* Return the environment vector represented as a 'char **'.  */
  74   char **envp () const;
  75
  76 private:
  77   /* A vector containing the environment variables.  */
  78   std::vector<char *> m_environ_vector;
  79 };
  80
  81 #endif /* defined (ENVIRON_H) */