ladybird/Userland/Utilities/patch.cpp
2024-02-21 14:11:49 +01:00

107 lines
3.8 KiB
C++

/*
* Copyright (c) 2023-2024, Shannon Booth <shannon@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibCore/ArgsParser.h>
#include <LibCore/File.h>
#include <LibCore/System.h>
#include <LibDiff/Applier.h>
#include <LibDiff/Hunks.h>
#include <LibFileSystem/FileSystem.h>
#include <LibMain/Main.h>
static bool is_adding_file(Diff::Patch const& patch)
{
return patch.hunks[0].location.old_range.start_line == 0;
}
static bool is_removing_file(Diff::Patch const& patch)
{
return patch.hunks[0].location.new_range.start_line == 0;
}
static ErrorOr<ByteBuffer> read_content(StringView path_of_file_to_patch, Diff::Patch const& patch)
{
auto file_to_patch_or_error = Core::File::open(path_of_file_to_patch, Core::File::OpenMode::Read);
// Trivial case - no error reading the file.
if (!file_to_patch_or_error.is_error())
return TRY(file_to_patch_or_error.release_value()->read_until_eof());
auto const& error = file_to_patch_or_error.error();
// If the patch is adding a file then it is fine for opening the file to error out if it did not exist.
if (!is_adding_file(patch) || !error.is_errno() || error.code() != ENOENT)
return file_to_patch_or_error.release_error();
return ByteBuffer {};
}
static ErrorOr<void> do_patch(StringView path_of_file_to_patch, Diff::Patch const& patch)
{
ByteBuffer content = TRY(read_content(path_of_file_to_patch, patch));
auto lines = StringView(content).lines();
// Apply patch to a temporary file in case one or more of the hunks fails.
char tmp_output[] = "/tmp/patch.XXXXXX";
auto tmp_file = TRY(Core::File::adopt_fd(TRY(Core::System::mkstemp(tmp_output)), Core::File::OpenMode::ReadWrite));
StringView tmp_path { tmp_output, sizeof(tmp_output) };
TRY(Diff::apply_patch(*tmp_file, lines, patch));
// If the patched file ends up being empty, remove it, as the patch was a removal.
// Note that we cannot simply rely on the patch successfully applying and the patch claiming it is removing the file
// as there may be some trailing garbage at the end of file which was not inside the patch.
if (is_removing_file(patch)) {
if ((TRY(Core::System::stat(tmp_path))).st_size == 0)
return FileSystem::remove(path_of_file_to_patch, FileSystem::RecursionMode::Disallowed);
outln("Not deleting file {} as content differs from patch", path_of_file_to_patch);
}
return FileSystem::move_file(path_of_file_to_patch, tmp_path);
}
ErrorOr<int> serenity_main(Main::Arguments arguments)
{
StringView directory;
Optional<size_t> strip_count;
Core::ArgsParser args_parser;
args_parser.add_option(directory, "Change the working directory to <directory> before applying the patch file", "directory", 'd', "directory");
args_parser.add_option(strip_count, "Strip given number of leading path components from file names (defaults as basename)", "strip", 'p', "count");
args_parser.parse(arguments);
if (!directory.is_null())
TRY(Core::System::chdir(directory));
auto input = TRY(Core::File::standard_input());
auto patch_content = TRY(input->read_until_eof());
Diff::Parser parser(patch_content);
while (!parser.is_eof()) {
Diff::Patch patch = TRY(parser.parse_patch(strip_count));
if (patch.header.format == Diff::Format::Unknown)
break;
StringView to_patch;
if (FileSystem::is_regular_file(patch.header.old_file_path)) {
to_patch = patch.header.old_file_path;
} else if (is_adding_file(patch) || FileSystem::is_regular_file(patch.header.new_file_path)) {
to_patch = patch.header.new_file_path;
} else {
warnln("Unable to determine file to patch");
return 1;
}
outln("patching file {}", to_patch);
TRY(do_patch(to_patch, patch));
}
return 0;
}