search_path.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 <boost/process/config.hpp>
#include <filesystem>
#include <boost/tokenizer.hpp>
#include <boost/array.hpp>
#include <boost/system/error_code.hpp>
#include <string>
#include <stdexcept>
#include <stdlib.h>
#include <Shellapi.h>
 
namespace boost::process::windows
{
 
#if defined(_UNICODE) || defined(UNICODE)
    inline std::wstring search_path(const std::wstring& filename,
                                    std::wstring path = L"")
    {
        if (path.empty())
        {
            path = ::_wgetenv(L"PATH");
            if (path.empty())
                BOOST_PROCESS_THROW(std::runtime_error(
                                        "Environment variable PATH not found"));
        }
 
        typedef boost::tokenizer < boost::char_separator<wchar_t>,
                std::wstring::const_iterator, std::wstring > tokenizer;
        boost::char_separator<wchar_t> sep(L";");
        tokenizer tok(path, sep);
        for (tokenizer::iterator it = tok.begin(); it != tok.end(); ++it)
        {
            std::filesystem::path p = *it;
            p /= filename;
            boost::array<std::wstring, 4> extensions =
            { L"", L".exe", L".com", L".bat" };
            for (boost::array<std::wstring, 4>::iterator it2 = extensions.begin();
                 it2 != extensions.end(); ++it2)
            {
                std::filesystem::path p2 = p;
                p2 += *it2;
                boost::system::error_code ec;
                bool file = std::filesystem::is_regular_file(p2, ec);
                if (!ec && file &&
                    SHGetFileInfoW(p2.c_str(), 0, 0, 0, SHGFI_EXETYPE))
                {
                    return p2.wstring();
                }
            }
        }
        return L"";
    }
#else
    inline std::string search_path(const std::string& filename,
                                   std::string path = "")
    {
        if (path.empty())
        {
            path = ::getenv("PATH");
            if (path.empty())
                BOOST_PROCESS_THROW(std::runtime_error(
                                        "Environment variable PATH not found"));
        }
 
        using tokenizer = boost::tokenizer<boost::char_separator<char> >;
        boost::char_separator<char> sep(";");
        tokenizer tok(path, sep);
        for (tokenizer::iterator it = tok.begin(); it != tok.end(); ++it)
        {
            std::filesystem::path p = *it;
            p /= filename;
            boost::array<std::string, 4> extensions =
            { "", ".exe", ".com", ".bat" };
            for (boost::array<std::string, 4>::iterator it2 = extensions.begin();
                 it2 != extensions.end(); ++it2)
            {
                std::filesystem::path p2 = p;
                p2 += *it2;
                boost::system::error_code ec;
                bool file = std::filesystem::is_regular_file(p2, ec);
                if (!ec && file &&
                    SHGetFileInfoA(p2.string().c_str(), 0, 0, 0, SHGFI_EXETYPE))
                {
                    return p2.string();
                }
            }
        }
        return "";
    }
#endif
 
}