ladybird/Userland/Utilities/tac.cpp

/*
 * Copyright (c) 2021, Federico Guerinoni <guerinoni.federico@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <AK/Vector.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/File.h>
#include <unistd.h>

void print_lines(const Vector<String>& vec);

int main(int argc, char** argv)
{
    if (pledge("stdio rpath", nullptr) < 0) {
        perror("pledge");
        return 1;
    }

    const char* path = nullptr;
    Core::ArgsParser args_parser;
    args_parser.set_general_help("Concatenate files or pipes to stdout, last line first.");
    args_parser.add_positional_argument(path, "File path", "path", Core::ArgsParser::Required::No);
    args_parser.parse(argc, argv);

    RefPtr<Core::File> file;
    if (path == nullptr) {
        file = Core::File::standard_input();
    } else {
        auto file_or_error = Core::File::open(path, Core::File::ReadOnly);
        if (file_or_error.is_error()) {
            warnln("Failed to open {}: {}", path, file_or_error.error());
            return 1;
        }
        file = file_or_error.value();
    }

    Vector<String> lines;
    while (file->can_read_line()) {
        auto line = file->read_line();
        lines.append(line);
    }

    for (int i = lines.size() - 1; i >= 0; --i)
        outln("{}", lines[i]);

    return 0;
}