binutils-gdb/gdbsupport/gdb_argv_vec.h

/* Wrap std::vector<char *> that owns the 'char *' strings.

   Copyright (C) 2025 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   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.  If not, see <http://www.gnu.org/licenses/>.  */

#ifndef GDBSUPPORT_GDB_ARGV_VEC_H
#define GDBSUPPORT_GDB_ARGV_VEC_H

#include "gdbsupport/common-utils.h"
#include <vector>

namespace gdb
{

/* A class that wraps around a vector of 'char *' strings.  The class owns
   the strings within the vector and will release them by calling xfree()
   on each string when this classes destructor is called.  */
class argv_vec final
{
  /* Vector of strings.  This class owns the strings within the vector.
     This is at the start of the class so we can use decltype().  */
  std::vector<char *> m_args;

public:

  using value_type = decltype (m_args)::value_type;
  using iterator = decltype (m_args)::iterator;
  using const_iterator = decltype (m_args)::const_iterator;
  using reference = decltype (m_args)::reference;
  using const_reference = decltype (m_args)::const_reference;

  argv_vec ()
  {
    /* Nothing.  */
  }

  /* Move the owned strings from OTHER.  */
  argv_vec (argv_vec &&other)
  {
    this->m_args = std::move (other.m_args);
  }

  /* Don't currently support copying the strings from OTHER.  */
  argv_vec (const argv_vec &other) = delete;

  /* Move elements from OTHER.  Free currently owned strings.  */
  argv_vec &operator= (argv_vec &&other)
  {
    free_vector_argv (m_args);
    this->m_args = std::move (other.m_args);
    return *this;
  }

  /* Don't currently support copying the strings from OTHER.  */
  argv_vec &operator= (const argv_vec &other) = delete;

  /* Release the owned strings.  */
  ~argv_vec ()
  {
    free_vector_argv (m_args);
  }

  /* Append VALUE to the end of m_args.  This class takes ownership of
     VALUE, and will release VALUE by calling xfree() on it when this
     object is destroyed.  */
  void push_back (const value_type &value)
  {
    m_args.push_back (value);
  }

  /* Append VALUE to the end of m_args.  This class takes ownership of
     VALUE, and will release VALUE by calling xfree() on it when this
     object is destroyed.  */
  void push_back (value_type &&value)
  {
    m_args.push_back (value);
  }

  /* Like calling emplace_back on the underlying vector.  This class takes
     ownership of the value added to the vector, and will release the value
     by calling xfree() on it when this object is destroyed.  */
  template<typename... Args>
  reference emplace_back (Args &&...args)
  {
    return m_args.emplace_back (std::forward<Args> (args)...);
  }

  /* Non constant iterator to start of m_args.  */
  iterator begin ()
  {
    return m_args.begin ();
  }

  /* Non constant iterator to end of m_args.  */
  iterator end ()
  {
    return m_args.end ();
  }

  /* Constant iterator to start of m_args.  */
  const_iterator begin () const
  {
    return m_args.begin ();
  }

  /* Constant iterator to end of m_args.  */
  const_iterator end () const
  {
    return m_args.end ();
  }

  /* Return contiguous block of 'char *' pointers.  Ideally this would be
     const, but the execve interface to which this data is passed doesn't
     accept 'const char **'.  */
  char **argv ()
  {
    return m_args.data ();
  }

  /* Return a constant reference to the underlying vector.  */
  const decltype (m_args) &get () const
  {
    return m_args;
  }

  /* Return true when m_args is empty.  */
  bool empty () const
  {
    return m_args.empty ();
  }

  /* Clear the argument vector.  */
  void clear ()
  {
    free_vector_argv (m_args);
  }
};
} /* namespac gdb */

#endif /* GDBSUPPORT_GDB_ARGV_VEC_H */