//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// REQUIRES: can-create-symlinks
// UNSUPPORTED: c++03, c++11, c++14
// UNSUPPORTED: no-filesystem

// <filesystem>

// bool exists(file_status s) noexcept
// bool exists(path const& p);
// bool exists(path const& p, std::error_code& ec) noexcept;

#include <filesystem>
#include <type_traits>
#include <cassert>

#include "assert_macros.h"
#include "test_macros.h"
#include "filesystem_test_helper.h"
namespace fs = std::filesystem;
using namespace fs;

static void signature_test()
{
    file_status s; ((void)s);
    const path p; ((void)p);
    std::error_code ec; ((void)ec);
    ASSERT_NOEXCEPT(exists(s));
    ASSERT_NOEXCEPT(exists(p, ec));
    ASSERT_NOT_NOEXCEPT(exists(p));
}

static void exists_status_test()
{
    struct TestCase {
        file_type type;
        bool expect;
    };
    const TestCase testCases[] = {
        {file_type::none, false},
        {file_type::not_found, false},
        {file_type::regular, true},
        {file_type::directory, true},
        {file_type::symlink, true},
        {file_type::block, true},
        {file_type::character, true},
        {file_type::fifo, true},
        {file_type::socket, true},
        {file_type::unknown, true}
    };
    for (auto& TC : testCases) {
        file_status s(TC.type);
        assert(exists(s) == TC.expect);
    }
}

static void test_exist_not_found()
{
    static_test_env static_env;
    const path p = static_env.DNE;
    assert(exists(p) == false);

    assert(exists(static_env.Dir) == true);
    assert(exists(static_env.Dir / "dne") == false);
    // Whether <dir>/dne/.. is considered to exist or not is not necessarily
    // something we need to define, but the platform specific behaviour
    // does affect a few other tests, so clarify the root cause here.
#ifdef _WIN32
    assert(exists(static_env.Dir / "dne" / "..") == true);
#else
    assert(exists(static_env.Dir / "dne" / "..") == false);
#endif

    std::error_code ec = GetTestEC();
    assert(exists(p, ec) == false);
    assert(!ec);
}

static void test_exists_fails()
{
#ifdef _WIN32
    // Windows doesn't support setting perms::none to trigger failures
    // reading directories; test using a special inaccessible directory
    // instead.
    const path p = GetWindowsInaccessibleDir();
    if (p.empty())
        return;
#else
    scoped_test_env env;
    const path dir = env.create_dir("dir");
    const path p = env.create_file("dir/file", 42);
    permissions(dir, perms::none);
#endif

    std::error_code ec;
    assert(exists(p, ec) == false);
    assert(ec);

    TEST_THROWS_TYPE(filesystem_error, exists(p));
}

#ifndef _WIN32
// Checking for the existence of an invalid long path name doesn't
// trigger errors on windows.
static void test_name_too_long() {
    std::string long_name(2500, 'a');
    const path file(long_name);

    std::error_code ec;
    assert(exists(file, ec) == false);
    assert(ec);
}
#endif // _WIN32

int main(int, char**) {
    signature_test();
    exists_status_test();
    test_exist_not_found();
    test_exists_fails();
#ifndef _WIN32
    test_name_too_long();
#endif

    return 0;
}