ladybird/Userland/Utilities/tac.cpp
2022-01-09 04:26:16 -08:00

79 lines
2.1 KiB
C++

/*
* Copyright (c) 2021-2022, Federico Guerinoni <guerinoni.federico@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibCore/ArgsParser.h>
#include <LibCore/System.h>
#include <LibMain/Main.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
ErrorOr<int> serenity_main(Main::Arguments arguments)
{
TRY(Core::System::pledge("stdio rpath"));
Vector<StringView> paths;
Core::ArgsParser args_parser;
args_parser.set_general_help("Concatenate files or pipes to stdout, last line first.");
args_parser.add_positional_argument(paths, "File path(s)", "path", Core::ArgsParser::Required::No);
args_parser.parse(arguments);
Vector<FILE*> streams;
auto num_paths = paths.size();
streams.ensure_capacity(num_paths ? num_paths : 1);
if (!paths.is_empty()) {
for (auto const& path : paths) {
FILE* stream = nullptr;
if (path == "-"sv) {
stream = stdin;
} else {
stream = fopen(String(path).characters(), "r");
if (!stream) {
warnln("Failed to open {}: {}", path, strerror(errno));
continue;
}
}
streams.append(stream);
}
} else {
streams.append(stdin);
}
char* buffer = nullptr;
ScopeGuard guard = [&] {
free(buffer);
for (auto* stream : streams) {
if (fclose(stream))
perror("fclose");
}
};
TRY(Core::System::pledge("stdio"));
for (auto* stream : streams) {
Vector<String> lines;
for (;;) {
size_t n = 0;
errno = 0;
ssize_t buflen = getline(&buffer, &n, stream);
if (buflen == -1) {
if (errno != 0) {
perror("getline");
return 1;
}
break;
}
lines.append({ buffer, Chomp });
}
for (int i = lines.size() - 1; i >= 0; --i)
outln("{}", lines[i]);
}
return 0;
}