filesystem.cpp

// Copyright (c) 2019, QuantStack and Mamba Contributors
//
// Distributed under the terms of the BSD 3-Clause License.
//
// The full license is in the file LICENSE, distributed with this software.

#ifdef _WIN32
#include <algorithm>
#endif
#include <filesystem>
#include <string>

#ifndef _WIN32
#include <fcntl.h>
#include <pwd.h>
#include <sys/stat.h>
#include <unistd.h>
// We can use the presence of UTIME_OMIT to detect platforms that provide
// utimensat.
#if defined(UTIME_OMIT)
#define USE_UTIMENSAT
#endif
#endif

#include "mamba/fs/filesystem.hpp"
#include "mamba/util/encoding.hpp"

namespace mamba::fs
{

#if defined(_WIN32)
    // Maintain `\` on Windows, `/` on other platforms
    std::filesystem::path normalized_separators(std::filesystem::path path)
    {
        auto native_string = path.native();
        static constexpr wchar_t platform_sep = L'\\';
        static constexpr wchar_t other_sep = L'/';
        std::replace(native_string.begin(), native_string.end(), other_sep, platform_sep);
        path = std::move(native_string);
        return path;
    }
#else
    // noop on non-Windows platforms
    std::filesystem::path normalized_separators(std::filesystem::path path)
    {
        return path;
    }
#endif

    std::string to_utf8(const std::filesystem::path& path, Utf8Options utf8_options)
    {
        const auto u8str = [&]
        {
            if (utf8_options.normalize_sep)
            {
                return normalized_separators(path).u8string();
            }
            else
            {
                return path.u8string();
            }
        }();

        return util::to_utf8_std_string(u8str);
    }

    std::filesystem::path from_utf8(std::string_view u8string)
    {
        return normalized_separators(util::to_u8string(u8string));
    }

    void last_write_time(const u8path& path, now, std::error_code& ec) noexcept
    {
#if defined(USE_UTIMENSAT)
        if (utimensat(AT_FDCWD, path.string().c_str(), NULL, 0) == -1)
        {
            ec = std::error_code(errno, std::generic_category());
        }
#else
        auto new_time = fs::file_time_type::clock::now();
        std::filesystem::last_write_time(path, new_time, ec);
#endif
    }

    bool has_permissions(const u8path& path, const fs::perms& perm)
    {
        // Get path permissions
        auto p = std::filesystem::status(path).permissions();

        // Path perms must include wanted perms
        return perm == (p & perm);
    }
}