ladybird/Meta/Lagom/Tools/CodeGenerators/LibWeb/GenerateCSSTransformFunctions.cpp

/*
 * Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "GeneratorUtil.h"
#include <AK/GenericLexer.h>
#include <AK/SourceGenerator.h>
#include <AK/StringBuilder.h>
#include <LibCore/ArgsParser.h>
#include <LibMain/Main.h>

ErrorOr<void> generate_header_file(JsonObject& transforms_data, Core::Stream::File& file);
ErrorOr<void> generate_implementation_file(JsonObject& transforms_data, Core::Stream::File& file);

ErrorOr<int> serenity_main(Main::Arguments arguments)
{
    StringView generated_header_path;
    StringView generated_implementation_path;
    StringView identifiers_json_path;

    Core::ArgsParser args_parser;
    args_parser.add_option(generated_header_path, "Path to the TransformFunctions header file to generate", "generated-header-path", 'h', "generated-header-path");
    args_parser.add_option(generated_implementation_path, "Path to the TransformFunctions implementation file to generate", "generated-implementation-path", 'c', "generated-implementation-path");
    args_parser.add_option(identifiers_json_path, "Path to the JSON file to read from", "json-path", 'j', "json-path");
    args_parser.parse(arguments);

    auto json = TRY(read_entire_file_as_json(identifiers_json_path));
    VERIFY(json.is_object());
    auto transforms_data = json.as_object();

    auto generated_header_file = TRY(Core::Stream::File::open(generated_header_path, Core::Stream::OpenMode::Write));
    auto generated_implementation_file = TRY(Core::Stream::File::open(generated_implementation_path, Core::Stream::OpenMode::Write));

    TRY(generate_header_file(transforms_data, *generated_header_file));
    TRY(generate_implementation_file(transforms_data, *generated_implementation_file));

    return 0;
}

static String title_casify_transform_function(StringView input)
{
    // Transform function names look like `fooBar`, so we just have to make the first character uppercase.
    StringBuilder builder;
    builder.append(toupper(input[0]));
    builder.append(input.substring_view(1));
    return builder.to_string();
}

ErrorOr<void> generate_header_file(JsonObject& transforms_data, Core::Stream::File& file)
{
    StringBuilder builder;
    SourceGenerator generator { builder };

    generator.append(R"~~~(
#pragma once

#include <AK/Optional.h>
#include <AK/StringView.h>

namespace Web::CSS {

)~~~");

    generator.appendln("enum class TransformFunction {");
    transforms_data.for_each_member([&](auto& name, auto&) {
        auto member_generator = generator.fork();
        member_generator.set("name:titlecase", title_casify_transform_function(name));
        member_generator.appendln("    @name:titlecase@,");
    });
    generator.appendln("};");

    generator.appendln("Optional<TransformFunction> transform_function_from_string(StringView);");
    generator.appendln("StringView to_string(TransformFunction);");

    generator.append(R"~~~(
enum class TransformFunctionParameterType {
    Angle,
    LengthPercentage,
    Number,
};

struct TransformFunctionMetadata {
    size_t min_parameters;
    size_t max_parameters;
    TransformFunctionParameterType parameter_type;
};
TransformFunctionMetadata transform_function_metadata(TransformFunction);
)~~~");

    generator.appendln("\n}");

    TRY(file.write(generator.as_string_view().bytes()));
    return {};
}

ErrorOr<void> generate_implementation_file(JsonObject& transforms_data, Core::Stream::File& file)
{
    StringBuilder builder;
    SourceGenerator generator { builder };

    generator.append(R"~~~(
#include <LibWeb/CSS/TransformFunctions.h>
#include <AK/Assertions.h>

namespace Web::CSS {
)~~~");

    generator.append(R"~~~(
Optional<TransformFunction> transform_function_from_string(StringView name)
{
)~~~");
    transforms_data.for_each_member([&](auto& name, auto&) {
        auto member_generator = generator.fork();
        member_generator.set("name", name);
        member_generator.set("name:titlecase", title_casify_transform_function(name));
        member_generator.append(R"~~~(
    if (name.equals_ignoring_case("@name@"sv))
        return TransformFunction::@name:titlecase@;
)~~~");
    });
    generator.append(R"~~~(
    return {};
}
)~~~");

    generator.append(R"~~~(
StringView to_string(TransformFunction transform_function)
{
    switch (transform_function) {
)~~~");
    transforms_data.for_each_member([&](auto& name, auto&) {
        auto member_generator = generator.fork();
        member_generator.set("name", name);
        member_generator.set("name:titlecase", title_casify_transform_function(name));
        member_generator.append(R"~~~(
    case TransformFunction::@name:titlecase@:
        return "@name@"sv;
)~~~");
    });
    generator.append(R"~~~(
    default:
        VERIFY_NOT_REACHED();
    }
}
)~~~");

    generator.append(R"~~~(
TransformFunctionMetadata transform_function_metadata(TransformFunction transform_function)
{
    switch (transform_function) {
)~~~");
    transforms_data.for_each_member([&](auto& name, auto& value) {
        VERIFY(value.is_object());
        auto parameters_string = value.as_object().get("parameters"sv).as_string();
        GenericLexer lexer { parameters_string };

        VERIFY(lexer.consume_specific('<'));
        auto parameter_type_name = lexer.consume_until('>');
        VERIFY(lexer.consume_specific('>'));

        StringView parameter_type = ""sv;
        if (parameter_type_name == "angle"sv)
            parameter_type = "Angle"sv;
        else if (parameter_type_name == "length-percentage"sv)
            parameter_type = "LengthPercentage"sv;
        else if (parameter_type_name == "number"sv)
            parameter_type = "Number"sv;
        else
            VERIFY_NOT_REACHED();

        StringView min_parameters = "1"sv;
        StringView max_parameters = "1"sv;
        if (!lexer.is_eof()) {
            VERIFY(lexer.consume_specific('{'));
            min_parameters = lexer.consume_until([](auto c) { return c == ',' || c == '}'; });
            if (lexer.consume_specific(','))
                max_parameters = lexer.consume_until('}');
            else
                max_parameters = min_parameters;
            VERIFY(lexer.consume_specific('}'));
        }
        VERIFY(lexer.is_eof());

        auto member_generator = generator.fork();
        member_generator.set("name:titlecase", title_casify_transform_function(name));
        member_generator.set("min_parameters", min_parameters);
        member_generator.set("max_parameters", max_parameters);
        member_generator.set("parameter_type", parameter_type);
        member_generator.append(R"~~~(
    case TransformFunction::@name:titlecase@:
        return TransformFunctionMetadata {
            .min_parameters = @min_parameters@,
            .max_parameters = @max_parameters@,
            .parameter_type = TransformFunctionParameterType::@parameter_type@
        };
)~~~");
    });
    generator.append(R"~~~(
    default:
        VERIFY_NOT_REACHED();
    }
}
)~~~");

    generator.appendln("\n}");

    TRY(file.write(generator.as_string_view().bytes()));
    return {};
}