set_env.hpp

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// Copyright (c) 2006, 2007 Julio M. Merino Vidal
// Copyright (c) 2008 Ilya Sokolov, Boris Schaeling
// Copyright (c) 2009 Boris Schaeling
// Copyright (c) 2010 Felipe Tanus, Boris Schaeling
// Copyright (c) 2011, 2012 Jeff Flinn, Boris Schaeling
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include <Windows.h>
#include <boost/process/windows/initializers/initializer_base.hpp>
#include <boost/range/numeric.hpp>
#include <boost/range/algorithm/copy.hpp>
#include <boost/range/algorithm/for_each.hpp>
#include <boost/shared_array.hpp>
#include <iterator>
#include <cstddef>
 
namespace boost::process::windows::initializers
{
 
    template <class Range, bool Unicode>
    class set_env_ : public initializer_base
    {
    private:
        using String = typename Range::value_type;
        using Char = typename String::value_type;
 
        static std::size_t add_size(std::size_t size, const String& s)
        {
            return size + s.size() + 1u;
        }
 
        struct copy
        {
            Char* it_;
 
            copy(Char* it) : it_(it) {}
 
            void operator()(const String& s)
            {
                it_ = boost::copy(s, it_);
                *it_ = 0;
                ++it_;
            }
        };
 
    public:
        set_env_(const Range& envs)
            : size_(boost::accumulate(envs, 0, add_size) + 1),
              env_(new Char[size_])
        {
            boost::for_each(envs, copy(env_.get()));
            env_[size_ - 1] = 0;
        }
 
        template <class WindowsExecutor>
        void on_CreateProcess_setup(WindowsExecutor& e) const
        {
            e.env = env_.get();
            if (Unicode)
            {
                e.creation_flags |= CREATE_UNICODE_ENVIRONMENT;
            }
        }
 
    private:
        std::size_t size_;
        boost::shared_array<Char> env_;
    };
 
#if defined(_UNICODE) || defined(UNICODE)
    template <class Range>
    set_env_<Range, true> set_env(const Range& envs)
    {
        return set_env_<Range, true>(envs);
    }
#else
    template <class Range>
    set_env_<Range, false> set_env(const Range& envs)
    {
        return set_env_<Range, false>(envs);
    }
#endif
 
}