ladybird/Userland/Utilities/cmp.cpp
2022-03-19 11:01:49 -07:00

101 lines
3.2 KiB
C++

/*
* Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibCore/ArgsParser.h>
#include <LibCore/Stream.h>
#include <LibCore/System.h>
#include <LibMain/Main.h>
#include <unistd.h>
static ErrorOr<NonnullOwnPtr<Core::Stream::BufferedFile>> open_file_or_stdin(String const& filename)
{
OwnPtr<Core::Stream::File> file;
if (filename == "-") {
file = TRY(Core::Stream::File::adopt_fd(STDIN_FILENO, Core::Stream::OpenMode::Read));
} else {
file = TRY(Core::Stream::File::open(filename, Core::Stream::OpenMode::Read));
}
return TRY(Core::Stream::BufferedFile::create(file.release_nonnull()));
}
ErrorOr<int> serenity_main(Main::Arguments arguments)
{
Main::set_return_code_for_errors(2);
TRY(Core::System::pledge("stdio rpath"));
Core::ArgsParser parser;
String filename1;
String filename2;
bool verbose = false;
bool silent = false;
parser.set_general_help("Compare two files, and report the first byte that does not match. Returns 0 if files are identical, or 1 if they differ.");
parser.add_positional_argument(filename1, "First file to compare", "file1", Core::ArgsParser::Required::Yes);
parser.add_positional_argument(filename2, "Second file to compare", "file2", Core::ArgsParser::Required::Yes);
parser.add_option(verbose, "Output every byte mismatch, not just the first", "verbose", 'l');
parser.add_option(silent, "Disable all output", "silent", 's');
parser.parse(arguments);
// When opening STDIN as both files, the results are undefined.
// Let's just report that it matches.
if (filename1 == "-" && filename2 == "-")
return 0;
auto file1 = TRY(open_file_or_stdin(filename1));
auto file2 = TRY(open_file_or_stdin(filename2));
TRY(Core::System::unveil(nullptr, nullptr));
int line_number = 1;
int byte_number = 1;
Array<u8, 1> buffer1;
Array<u8, 1> buffer2;
bool files_match = true;
auto report_mismatch = [&]() {
files_match = false;
if (silent)
return;
if (verbose)
outln("{} {:o} {:o}", byte_number, buffer1[0], buffer2[0]);
else
outln("{} {} differ: char {}, line {}", filename1, filename2, byte_number, line_number);
};
auto report_eof = [&](auto& shorter_file_name) {
files_match = false;
if (silent)
return;
auto additional_info = verbose
? String::formatted(" after byte {}", byte_number)
: String::formatted(" after byte {}, line {}", byte_number, line_number);
warnln("cmp: EOF on {}{}", shorter_file_name, additional_info);
};
while (true) {
TRY(file1->read(buffer1));
TRY(file2->read(buffer2));
if (file1->is_eof() && file2->is_eof())
break;
if (file1->is_eof() || file2->is_eof()) {
report_eof(file1->is_eof() ? filename1 : filename2);
break;
}
if (buffer1[0] != buffer2[0]) {
report_mismatch();
if (!verbose)
break;
}
if (buffer1[0] == '\n')
++line_number;
++byte_number;
}
return files_match ? 0 : 1;
}