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/*
* Copyright (c) 2022, Eli Youngs <eli.m.youngs@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/CharacterTypes.h>
#include <AK/GenericLexer.h>
#include <AK/Vector.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/Stream.h>
#include <LibCore/System.h>
#include <LibMain/Main.h>
#include <LibRegex/RegexMatcher.h>
#include <LibRegex/RegexOptions.h>
struct SubstitutionCommand {
Regex<PosixExtended> regex;
StringView replacement;
PosixOptions options;
Optional<StringView> output_filepath;
};
static Vector<StringView> split_flags(StringView const& input)
{
Vector<StringView> flags;
auto lexer = GenericLexer(input);
while (!lexer.is_eof()) {
StringView flag;
if (lexer.next_is(is_ascii_digit)) {
flag = lexer.consume_while(is_ascii_digit);
} else if (lexer.peek() == 'w') {
flag = lexer.consume_all();
} else {
flag = lexer.consume(1);
}
flags.append(flag);
}
return flags;
}
static ErrorOr<SubstitutionCommand> parse_command(StringView command)
{
auto generic_error_message = "Incomplete substitution command"sv;
auto lexer = GenericLexer(command);
auto address = lexer.consume_until('s');
if (!address.is_empty())
warnln("sed: Addresses are currently ignored");
if (!lexer.consume_specific('s'))
return Error::from_string_view(generic_error_message);
if (lexer.is_eof())
return Error::from_string_view(generic_error_message);
auto delimiter = lexer.consume();
if (delimiter == '\n' || delimiter == '\\')
return Error::from_string_literal("\\n and \\ cannot be used as delimiters.");
auto pattern = lexer.consume_until(delimiter);
if (pattern.is_empty())
return Error::from_string_literal("Substitution patterns cannot be empty.");
if (!lexer.consume_specific(delimiter))
return Error::from_string_view(generic_error_message);
auto replacement = lexer.consume_until(delimiter);
// According to Posix, "s/x/y" is an invalid substitution command.
// It must have a closing delimiter: "s/x/y/"
if (!lexer.consume_specific(delimiter))
return Error::from_string_literal("The substitution command was not properly terminated.");
PosixOptions options = PosixOptions(PosixFlags::Global | PosixFlags::SingleMatch);
Optional<StringView> output_filepath;
auto flags = split_flags(lexer.consume_all());
for (auto const& flag : flags) {
if (flag.starts_with('w')) {
auto flag_filepath = flag.substring_view(1).trim_whitespace();
if (flag_filepath.is_empty())
return Error::from_string_literal("No filepath was provided for the 'w' flag.");
output_filepath = flag_filepath;
} else if (flag == "g"sv) {
// Allow multiple matches per line by un-setting the SingleMatch flag
options &= ~PosixFlags::SingleMatch;
} else if (flag == "i"sv || flag == "I"sv) {
options |= PosixFlags::Insensitive;
} else {
warnln("sed: Unsupported flag: {}", flag);
}
}
return SubstitutionCommand { Regex<PosixExtended> { pattern }, replacement, options, output_filepath };
}
ErrorOr<int> serenity_main(Main::Arguments args)
{
TRY(Core::System::pledge("stdio cpath rpath wpath"));
Core::ArgsParser args_parser;
StringView command_input;
Vector<StringView> filepaths;
args_parser.add_positional_argument(command_input, "Command", "command_input", Core::ArgsParser::Required::Yes);
args_parser.add_positional_argument(filepaths, "File", "file", Core::ArgsParser::Required::No);
args_parser.parse(args);
auto command = TRY(parse_command(command_input));
Optional<NonnullOwnPtr<Core::Stream::File>> maybe_output_file;
if (command.output_filepath.has_value())
maybe_output_file = TRY(Core::Stream::File::open_file_or_standard_stream(command.output_filepath.release_value(), Core::Stream::OpenMode::Write));
if (filepaths.is_empty())
filepaths = { "-"sv };
Array<u8, PAGE_SIZE> buffer {};
for (auto const& filepath : filepaths) {
auto file_unbuffered = TRY(Core::Stream::File::open_file_or_standard_stream(filepath, Core::Stream::OpenMode::Read));
auto file = TRY(Core::Stream::BufferedFile::create(move(file_unbuffered)));
while (!file->is_eof()) {
auto line = TRY(file->read_line(buffer));
// Substitutions can apply to blank lines in the middle of a file,
// but not to the trailing newline that marks the end of a file.
if (line.is_empty() && file->is_eof())
break;
auto result = command.regex.replace(line, command.replacement, command.options);
outln(result);
if (maybe_output_file.has_value()) {
auto const& output_file = maybe_output_file.value();
TRY(output_file->write(result.bytes()));
TRY(output_file->write("\n"sv.bytes()));
}
}
}
return 0;
}
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