jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include <LibCore/ArgsParser.h>
8#include <LibCore/File.h>
9#include <LibCore/System.h>
10#include <LibMain/Main.h>
11#include <unistd.h>
12
13static ErrorOr<NonnullOwnPtr<Core::BufferedFile>> open_file_or_stdin(DeprecatedString const& filename)
14{
15 OwnPtr<Core::File> file;
16 if (filename == "-") {
17 file = TRY(Core::File::adopt_fd(STDIN_FILENO, Core::File::OpenMode::Read));
18 } else {
19 file = TRY(Core::File::open(filename, Core::File::OpenMode::Read));
20 }
21 return TRY(Core::BufferedFile::create(file.release_nonnull()));
22}
23
24ErrorOr<int> serenity_main(Main::Arguments arguments)
25{
26 Main::set_return_code_for_errors(2);
27 TRY(Core::System::pledge("stdio rpath"));
28
29 Core::ArgsParser parser;
30 DeprecatedString filename1;
31 DeprecatedString filename2;
32 bool verbose = false;
33 bool silent = false;
34
35 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.");
36 parser.add_positional_argument(filename1, "First file to compare", "file1", Core::ArgsParser::Required::Yes);
37 parser.add_positional_argument(filename2, "Second file to compare", "file2", Core::ArgsParser::Required::Yes);
38 parser.add_option(verbose, "Output every byte mismatch, not just the first", "verbose", 'l');
39 parser.add_option(silent, "Disable all output", "silent", 's');
40 parser.parse(arguments);
41
42 // When opening STDIN as both files, the results are undefined.
43 // Let's just report that it matches.
44 if (filename1 == "-" && filename2 == "-")
45 return 0;
46
47 auto file1 = TRY(open_file_or_stdin(filename1));
48 auto file2 = TRY(open_file_or_stdin(filename2));
49 TRY(Core::System::unveil(nullptr, nullptr));
50
51 int line_number = 1;
52 int byte_number = 1;
53 Array<u8, 1> buffer1;
54 Array<u8, 1> buffer2;
55 bool files_match = true;
56
57 auto report_mismatch = [&]() {
58 files_match = false;
59 if (silent)
60 return;
61 if (verbose)
62 outln("{} {:o} {:o}", byte_number, buffer1[0], buffer2[0]);
63 else
64 outln("{} {} differ: char {}, line {}", filename1, filename2, byte_number, line_number);
65 };
66
67 auto report_eof = [&](auto& shorter_file_name) {
68 files_match = false;
69 if (silent)
70 return;
71 auto additional_info = verbose
72 ? DeprecatedString::formatted(" after byte {}", byte_number)
73 : DeprecatedString::formatted(" after byte {}, line {}", byte_number, line_number);
74 warnln("cmp: EOF on {}{}", shorter_file_name, additional_info);
75 };
76
77 while (true) {
78 TRY(file1->read_some(buffer1));
79 TRY(file2->read_some(buffer2));
80
81 if (file1->is_eof() && file2->is_eof())
82 break;
83
84 if (file1->is_eof() || file2->is_eof()) {
85 report_eof(file1->is_eof() ? filename1 : filename2);
86 break;
87 }
88
89 if (buffer1[0] != buffer2[0]) {
90 report_mismatch();
91 if (!verbose)
92 break;
93 }
94
95 if (buffer1[0] == '\n')
96 ++line_number;
97 ++byte_number;
98 }
99
100 return files_match ? 0 : 1;
101}