argv.hpp

//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012-2017 OpenVPN Technologies, Inc.
//
//    This program is free software: you can redistribute it and/or modify
//    it under the terms of the GNU General Public License Version 3
//    as published by the Free Software Foundation.
//
//    This program is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU General Public License for more details.
//
//    You should have received a copy of the GNU General Public License
//    along with this program in the COPYING file.
//    If not, see <http://www.gnu.org/licenses/>.

#ifndef OPENVPN_COMMON_ARGV_H
#define OPENVPN_COMMON_ARGV_H

#include <cstring>     // memcpy

#include <string>
#include <vector>

namespace openvpn {

  class Argv : public std::vector<std::string>
  {
  public:
    Argv(const size_t capacity=16)
    {
      reserve(capacity);
    }

    std::string to_string() const
    {
      std::string ret;
      bool first = true;
      for (const auto &s : *this)
	{
	  if (!first)
	    ret += ' ';
	  ret += s;
	  first = false;
	}
      return ret;
    }
  };

  class ArgvWrapper
  {
  public:
    explicit ArgvWrapper(const std::vector<std::string>& argv)
    {
      size_t i;
      argc = argv.size();
      cargv = new char *[argc+1];
      for (i = 0; i < argc; ++i)
	cargv[i] = string_alloc(argv[i]);
      cargv[i] = nullptr;
    }

    ArgvWrapper(ArgvWrapper&& rhs) noexcept
    {
      argc = rhs.argc;
      cargv = rhs.cargv;
      rhs.argc = 0;
      rhs.cargv = nullptr;
    }

    ArgvWrapper& operator=(ArgvWrapper&& rhs) noexcept
    {
      del();
      argc = rhs.argc;
      cargv = rhs.cargv;
      rhs.argc = 0;
      rhs.cargv = nullptr;
      return *this;
    }

    ~ArgvWrapper()
    {
      del();
    }

    char *const *c_argv() const noexcept
    {
      return cargv;
    }

    char **c_argv() noexcept
    {
      return cargv;
    }

    size_t c_argc() const noexcept
    {
      return argc;
    }

  private:
    ArgvWrapper(const ArgvWrapper&) = delete;
    ArgvWrapper& operator=(const ArgvWrapper&) = delete;

    static char *string_alloc(const std::string& s)
    {
      const char *sdata = s.c_str();
      const size_t slen = s.length();
      char *ret = new char[slen+1];
      std::memcpy(ret, sdata, slen);
      ret[slen] = '\0';
      return ret;
    }

    void del()
    {
      for (size_t i = 0; i < argc; ++i)
	delete [] cargv[i];
      delete [] cargv;
    }

    size_t argc;
    char **cargv;
  };

}

#endif