system.hpp

/*
    SPDX-License-Identifier: MIT
    Copyright © 2023-2024 Amebis
*/
 
#pragma once
 
#include "compat.hpp"
#if defined(_WIN32)
#include "windows.h"
#include <oaidl.h>
#include <tchar.h>
#else
#ifndef _LARGEFILE64_SOURCE
#define _LARGEFILE64_SOURCE // TODO: Make this -D compile-time project setting
#endif
#include <grp.h>
#include <pwd.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#endif
#include <regex>
#include <stdexcept>
#include <string_view>
#include <string>
 
#if defined(_WIN32)
#define PATH_SEPARATOR '\\'
#define PATH_SEPARATOR_STR "\\"
#else
#define PATH_SEPARATOR '/'
#define PATH_SEPARATOR_STR "/"
#endif
 
namespace stdex
{
#if defined(_WIN32)
    using sys_handle = HANDLE;
    const sys_handle invalid_handle = INVALID_HANDLE_VALUE;
#else
    using sys_handle = int;
    const sys_handle invalid_handle = (sys_handle)-1;
#endif
 
#if defined(_WIN32)
    inline DWORD sys_error() { return GetLastError(); }
#else
    inline int sys_error() { return errno; }
#endif
 
#if defined(_WIN32)
    using schar_t = TCHAR;
#else
    using schar_t = char;
#endif
 
    using sys_char = schar_t;
 
    using sstring = std::basic_string<stdex::schar_t>;
 
    using sys_string = sstring;
 
    using sstring_view = std::basic_string_view<stdex::schar_t, std::char_traits<stdex::schar_t>>;
 
    using sregex = std::basic_regex<stdex::schar_t>;
 
    struct sys_object_traits
    {
        static inline const sys_handle invalid_handle = stdex::invalid_handle;
 
        static void close(_In_ sys_handle h)
        {
#if defined(_WIN32)
            if (CloseHandle(h) || GetLastError() == ERROR_INVALID_HANDLE)
                return;
            throw std::system_error(GetLastError(), std::system_category(), "CloseHandle failed");
#else
            if (::close(h) >= 0 || errno == EBADF)
                return;
            throw std::system_error(errno, std::system_category(), "close failed");
#endif
        }
 
        static sys_handle duplicate(_In_ sys_handle h, _In_ bool inherit = false)
        {
            sys_handle h_new;
#if defined(_WIN32)
            HANDLE process = GetCurrentProcess();
            if (DuplicateHandle(process, h, process, &h_new, 0, inherit, DUPLICATE_SAME_ACCESS))
                return h_new;
            throw std::system_error(GetLastError(), std::system_category(), "DuplicateHandle failed");
#else
            _Unreferenced_(inherit);
            if ((h_new = dup(h)) >= 0)
                return h_new;
            throw std::system_error(errno, std::system_category(), "dup failed");
#endif
        }
    };
 
    template <class T = sys_handle, class TR = sys_object_traits>
    class basic_sys_object
    {
    public:
        basic_sys_object(_In_opt_ T h = TR::invalid_handle) : m_h(h) {}
 
        basic_sys_object(_In_ const basic_sys_object<T, TR>& other) : m_h(other.m_h != TR::invalid_handle ? TR::duplicate(other.m_h) : TR::invalid_handle) {}
 
        basic_sys_object& operator =(_In_ const basic_sys_object<T, TR>& other)
        {
            if (this != std::addressof(other)) {
                if (m_h != TR::invalid_handle)
                    TR::close(m_h);
                m_h = other.m_h != TR::invalid_handle ? TR::duplicate(other.m_h) : TR::invalid_handle;
            }
            return *this;
        }
 
        basic_sys_object(_Inout_ basic_sys_object<T, TR>&& other) noexcept : m_h(other.m_h)
        {
            other.m_h = TR::invalid_handle;
        }
 
        basic_sys_object& operator =(_Inout_ basic_sys_object<T, TR>&& other) noexcept
        {
            if (this != std::addressof(other)) {
                if (m_h != TR::invalid_handle)
                    TR::close(m_h);
                m_h = other.m_h;
                other.m_h = TR::invalid_handle;
            }
            return *this;
        }
 
        virtual ~basic_sys_object() noexcept(false)
        {
            if (m_h != TR::invalid_handle)
                TR::close(m_h);
        }
 
        virtual void close()
        {
            if (m_h != TR::invalid_handle) {
                TR::close(m_h);
                m_h = TR::invalid_handle;
            }
        }
 
        operator bool() const noexcept { return m_h != TR::invalid_handle; }
 
        T get() const noexcept { return m_h; }
 
    protected:
        T m_h;
    };
 
    using sys_object = basic_sys_object<sys_handle, sys_object_traits>;
 
#ifdef _WIN32
    template <class T>
    class safearray_accessor
    {
    public:
        safearray_accessor(_In_ LPSAFEARRAY sa) : m_sa(sa)
        {
            HRESULT hr = SafeArrayAccessData(sa, reinterpret_cast<void HUGEP**>(&m_data));
            if (FAILED(hr))
                throw std::system_error(hr, std::system_category(), "SafeArrayAccessData failed");
        }
 
        ~safearray_accessor()
        {
            SafeArrayUnaccessData(m_sa);
        }
 
        T* data() const { return m_data; }
 
    protected:
        LPSAFEARRAY m_sa;
        T* m_data;
    };
 
    struct SafeArrayDestroy_delete
    {
        void operator()(_In_ LPSAFEARRAY sa) const
        {
            SafeArrayDestroy(sa);
        }
    };
 
    struct SysFreeString_delete
    {
        void operator()(_In_ BSTR sa) const
        {
            SysFreeString(sa);
        }
    };
#endif
}