Meta: Replace GenerateCSSNumericFactoryMethods with a python generator

Adds a new `invoke_py_idl_generator` CMake helper for python scripts
that also produce an IDL file.

Meta/CMake/libweb_generators.cmake

@@ -104,10 +104,10 @@ function (generate_css_implementation)
         arguments -j "${LIBWEB_INPUT_FOLDER}/CSS/Keywords.json"
     )
 
-    invoke_idl_generator(
+    invoke_py_idl_generator(
         "GeneratedCSSNumericFactoryMethods.cpp"
         "GeneratedCSSNumericFactoryMethods.idl"
-        Lagom::GenerateCSSNumericFactoryMethods
+        "generate_libweb_css_numeric_factory_methods.py"
         "${LIBWEB_INPUT_FOLDER}/CSS/Units.json"
         "CSS/GeneratedCSSNumericFactoryMethods.h"
         "CSS/GeneratedCSSNumericFactoryMethods.cpp"

Meta/CMake/utils.cmake

@@ -135,6 +135,29 @@ function(invoke_idl_generator cpp_name idl_name generator primary_source header
     set(CURRENT_LIB_GENERATED ${CURRENT_LIB_GENERATED} PARENT_SCOPE)
 endfunction()
 
+function(invoke_py_idl_generator cpp_name idl_name script primary_source header implementation idl)
+    cmake_parse_arguments(invoke_py_idl_generator "" "" "arguments;dependencies" ${ARGN})
+
+    set(script_path "${LADYBIRD_SOURCE_DIR}/Meta/Generators/${script}")
+    add_custom_command(
+        OUTPUT "${header}" "${implementation}" "${idl}"
+        COMMAND ${Python3_EXECUTABLE} "${script_path}" -h "${header}.tmp" -c "${implementation}.tmp" -i "${idl}.tmp" ${invoke_py_idl_generator_arguments}
+        COMMAND "${CMAKE_COMMAND}" -E copy_if_different "${header}.tmp" "${header}"
+        COMMAND "${CMAKE_COMMAND}" -E copy_if_different "${implementation}.tmp" "${implementation}"
+        COMMAND "${CMAKE_COMMAND}" -E copy_if_different "${idl}.tmp" "${idl}"
+        COMMAND "${CMAKE_COMMAND}" -E remove "${header}.tmp" "${implementation}.tmp" "${idl}.tmp"
+        VERBATIM
+        DEPENDS "${script_path}" ${invoke_py_idl_generator_dependencies} "${primary_source}"
+    )
+
+    add_custom_target("generate_${cpp_name}" DEPENDS "${header}" "${implementation}" "${idl}")
+    add_custom_target("generate_${idl_name}" DEPENDS "generate_${cpp_name}")
+    add_dependencies(ladybird_codegen_accumulator "generate_${cpp_name}")
+    add_dependencies(ladybird_codegen_accumulator "generate_${idl_name}")
+    list(APPEND CURRENT_LIB_GENERATED "${name}")
+    set(CURRENT_LIB_GENERATED ${CURRENT_LIB_GENERATED} PARENT_SCOPE)
+endfunction()
+
 function(download_file_multisource urls path)
     cmake_parse_arguments(DOWNLOAD "" "SHA256" "" ${ARGN})
 

Meta/Generators/generate_libweb_css_numeric_factory_methods.py

@@ -0,0 +1,147 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2025-2026, Sam Atkins <sam@ladybird.org>
+# Copyright (c) 2026-present, the Ladybird developers.
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+import argparse
+import json
+import sys
+
+from pathlib import Path
+from typing import TextIO
+
+sys.path.append(str(Path(__file__).resolve().parent.parent))
+
+from Utils.utils import make_name_acceptable_cpp
+from Utils.utils import snake_casify
+
+
+def write_header_file(out: TextIO, units_data: dict) -> None:
+    out.write("""
+#pragma once
+
+#include <LibGC/Ptr.h>
+#include <LibJS/Forward.h>
+#include <LibWeb/Forward.h>
+#include <LibWeb/WebIDL/Types.h>
+
+// https://drafts.css-houdini.org/css-typed-om-1/#numeric-factory
+namespace Web::CSS {
+
+GC::Ref<CSSUnitValue> number(JS::VM&, WebIDL::Double value);
+GC::Ref<CSSUnitValue> percent(JS::VM&, WebIDL::Double value);
+""")
+
+    for dimension_name, units in units_data.items():
+        dimension_acceptable_cpp = make_name_acceptable_cpp(snake_casify(dimension_name, trim_leading_underscores=True))
+        out.write(f"\n// <{dimension_acceptable_cpp}>\n")
+        for unit_name in units:
+            unit_acceptable_cpp = make_name_acceptable_cpp(unit_name.lower())
+            out.write(f"GC::Ref<CSSUnitValue> {unit_acceptable_cpp}(JS::VM&, WebIDL::Double value);\n")
+
+    out.write("""
+}
+""")
+
+
+def write_implementation_file(out: TextIO, units_data: dict) -> None:
+    out.write("""
+#include <AK/FlyString.h>
+#include <LibJS/Runtime/VM.h>
+#include <LibWeb/CSS/CSSUnitValue.h>
+#include <LibWeb/CSS/GeneratedCSSNumericFactoryMethods.h>
+
+namespace Web::CSS {
+
+// https://drafts.css-houdini.org/css-typed-om-1/#numeric-factory
+inline GC::Ref<CSSUnitValue> numeric_factory(JS::VM& vm, WebIDL::Double value, FlyString unit)
+{
+    // All of the above methods must, when called with a double value, return a new CSSUnitValue whose value internal
+    // slot is set to value and whose unit internal slot is set to the name of the method as defined here.
+    return CSSUnitValue::create(*vm.current_realm(), value, move(unit));
+}
+
+GC::Ref<CSSUnitValue> number(JS::VM& vm, WebIDL::Double value)
+{
+    return numeric_factory(vm, value, "number"_fly_string);
+}
+
+GC::Ref<CSSUnitValue> percent(JS::VM& vm, WebIDL::Double value)
+{
+    return numeric_factory(vm, value, "percent"_fly_string);
+}
+
+""")
+
+    for dimension_name, units in units_data.items():
+        dimension_acceptable_cpp = make_name_acceptable_cpp(snake_casify(dimension_name, trim_leading_underscores=True))
+        out.write(f"\n// <{dimension_acceptable_cpp}>\n")
+        for unit_name in units:
+            unit_acceptable_cpp = make_name_acceptable_cpp(unit_name.lower())
+            out.write(f"""
+GC::Ref<CSSUnitValue> {unit_acceptable_cpp}(JS::VM& vm, WebIDL::Double value)
+{{
+    return numeric_factory(vm, value, "{unit_name}"_fly_string);
+}}
+""")
+
+    out.write("""
+}
+""")
+
+
+def write_idl_file(out: TextIO, units_data: dict) -> None:
+    out.write("""
+partial namespace CSS {
+    CSSUnitValue number(double value);
+    CSSUnitValue percent(double value);
+
+""")
+
+    for dimension_name, units in units_data.items():
+        dimension_acceptable_cpp = make_name_acceptable_cpp(snake_casify(dimension_name, trim_leading_underscores=True))
+        out.write(f"""
+    // <{dimension_acceptable_cpp}>
+""")
+        for unit_name in units:
+            unit_acceptable_cpp = make_name_acceptable_cpp(unit_name.lower())
+            out.write(f"    [ImplementedAs={unit_acceptable_cpp}] CSSUnitValue {unit_name}(double value);\n")
+
+    out.write("""
+};
+""")
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Generate CSS NumericFactoryMethods", add_help=False)
+    parser.add_argument("--help", action="help", help="Show this help message and exit")
+    parser.add_argument(
+        "-h", "--header", required=True, help="Path to the CSSNumericFactoryMethods header file to generate"
+    )
+    parser.add_argument(
+        "-c",
+        "--implementation",
+        required=True,
+        help="Path to the CSSNumericFactoryMethods implementation file to generate",
+    )
+    parser.add_argument("-i", "--idl", required=True, help="Path to the CSSNumericFactoryMethods IDL file to generate")
+    parser.add_argument("-j", "--json", required=True, help="Path to the JSON file to read from")
+    args = parser.parse_args()
+
+    with open(args.json, "r", encoding="utf-8") as input_file:
+        units_data = json.load(input_file)
+
+    with open(args.header, "w", encoding="utf-8") as output_file:
+        write_header_file(output_file, units_data)
+
+    with open(args.implementation, "w", encoding="utf-8") as output_file:
+        write_implementation_file(output_file, units_data)
+
+    with open(args.idl, "w", encoding="utf-8") as output_file:
+        write_idl_file(output_file, units_data)
+
+
+if __name__ == "__main__":
+    main()

Meta/Lagom/Tools/CodeGenerators/LibWeb/CMakeLists.txt

@@ -1,6 +1,5 @@
 set(SOURCES "") # avoid pulling SOURCES from parent scope
 
-lagom_tool(GenerateCSSNumericFactoryMethods SOURCES GenerateCSSNumericFactoryMethods.cpp LIBS LibMain)
 lagom_tool(GenerateCSSPropertyID            SOURCES GenerateCSSPropertyID.cpp LIBS LibMain)
 lagom_tool(GenerateCSSStyleProperties       SOURCES GenerateCSSStyleProperties.cpp LIBS LibMain)
 lagom_tool(GenerateWindowOrWorkerInterfaces SOURCES GenerateWindowOrWorkerInterfaces.cpp LIBS LibMain LibIDL)

Meta/Lagom/Tools/CodeGenerators/LibWeb/GenerateCSSNumericFactoryMethods.cpp

@@ -1,178 +0,0 @@
-/*
- * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include "GeneratorUtil.h"
-#include <AK/SourceGenerator.h>
-#include <AK/StringBuilder.h>
-#include <LibCore/ArgsParser.h>
-#include <LibMain/Main.h>
-
-ErrorOr<void> generate_header_file(JsonObject& units_data, Core::File& file);
-ErrorOr<void> generate_implementation_file(JsonObject& units_data, Core::File& file);
-ErrorOr<void> generate_idl_file(JsonObject& units_data, Core::File& file);
-
-ErrorOr<int> ladybird_main(Main::Arguments arguments)
-{
-    StringView generated_header_path;
-    StringView generated_implementation_path;
-    StringView generated_idl_path;
-    StringView units_json_path;
-
-    Core::ArgsParser args_parser;
-    args_parser.add_option(generated_header_path, "Path to the CSSNumericFactoryMethods header file to generate", "generated-header-path", 'h', "generated-header-path");
-    args_parser.add_option(generated_implementation_path, "Path to the CSSNumericFactoryMethods implementation file to generate", "generated-implementation-path", 'c', "generated-implementation-path");
-    args_parser.add_option(generated_idl_path, "Path to the CSSNumericFactoryMethods IDL file to generate", "generated-idl-path", 'i', "generated-idl-path");
-    args_parser.add_option(units_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(units_json_path));
-    VERIFY(json.is_object());
-    auto units_data = json.as_object();
-
-    auto generated_header_file = TRY(Core::File::open(generated_header_path, Core::File::OpenMode::Write));
-    auto generated_implementation_file = TRY(Core::File::open(generated_implementation_path, Core::File::OpenMode::Write));
-    auto generated_idl_file = TRY(Core::File::open(generated_idl_path, Core::File::OpenMode::Write));
-
-    TRY(generate_header_file(units_data, *generated_header_file));
-    TRY(generate_implementation_file(units_data, *generated_implementation_file));
-    TRY(generate_idl_file(units_data, *generated_idl_file));
-
-    return 0;
-}
-
-ErrorOr<void> generate_header_file(JsonObject& units_data, Core::File& file)
-{
-    StringBuilder builder;
-    SourceGenerator generator { builder };
-
-    generator.append(R"~~~(
-#pragma once
-
-#include <LibGC/Ptr.h>
-#include <LibJS/Forward.h>
-#include <LibWeb/Forward.h>
-#include <LibWeb/WebIDL/Types.h>
-
-// https://drafts.css-houdini.org/css-typed-om-1/#numeric-factory
-namespace Web::CSS {
-
-GC::Ref<CSSUnitValue> number(JS::VM&, WebIDL::Double value);
-GC::Ref<CSSUnitValue> percent(JS::VM&, WebIDL::Double value);
-)~~~");
-
-    units_data.for_each_member([&](auto& dimension_name, JsonValue const& dimension) {
-        auto dimension_generator = generator.fork();
-        dimension_generator.set("dimension:acceptable_cpp", make_name_acceptable_cpp(snake_casify(dimension_name, TrimLeadingUnderscores::Yes)));
-        dimension_generator.appendln("\n// <@dimension:acceptable_cpp@>");
-
-        dimension.as_object().for_each_member([&](auto& unit_name, JsonValue const&) {
-            auto unit_generator = dimension_generator.fork();
-            unit_generator.set("unit:acceptable_cpp", make_name_acceptable_cpp(unit_name.to_ascii_lowercase()));
-            unit_generator.appendln("GC::Ref<CSSUnitValue> @unit:acceptable_cpp@(JS::VM&, WebIDL::Double value);");
-        });
-    });
-
-    generator.append(R"~~~(
-}
-)~~~");
-
-    TRY(file.write_until_depleted(generator.as_string_view().bytes()));
-    return {};
-}
-
-ErrorOr<void> generate_implementation_file(JsonObject& units_data, Core::File& file)
-{
-    StringBuilder builder;
-    SourceGenerator generator { builder };
-
-    generator.append(R"~~~(
-#include <AK/FlyString.h>
-#include <LibJS/Runtime/VM.h>
-#include <LibWeb/CSS/CSSUnitValue.h>
-#include <LibWeb/CSS/GeneratedCSSNumericFactoryMethods.h>
-
-namespace Web::CSS {
-
-// https://drafts.css-houdini.org/css-typed-om-1/#numeric-factory
-inline GC::Ref<CSSUnitValue> numeric_factory(JS::VM& vm, WebIDL::Double value, FlyString unit)
-{
-    // All of the above methods must, when called with a double value, return a new CSSUnitValue whose value internal
-    // slot is set to value and whose unit internal slot is set to the name of the method as defined here.
-    return CSSUnitValue::create(*vm.current_realm(), value, move(unit));
-}
-
-GC::Ref<CSSUnitValue> number(JS::VM& vm, WebIDL::Double value)
-{
-    return numeric_factory(vm, value, "number"_fly_string);
-}
-
-GC::Ref<CSSUnitValue> percent(JS::VM& vm, WebIDL::Double value)
-{
-    return numeric_factory(vm, value, "percent"_fly_string);
-}
-
-)~~~");
-
-    units_data.for_each_member([&](auto& dimension_name, JsonValue const& dimension) {
-        auto dimension_generator = generator.fork();
-        dimension_generator.set("dimension:acceptable_cpp", make_name_acceptable_cpp(snake_casify(dimension_name, TrimLeadingUnderscores::Yes)));
-        dimension_generator.appendln("\n// <@dimension:acceptable_cpp@>");
-
-        dimension.as_object().for_each_member([&](auto& unit_name, JsonValue const&) {
-            auto unit_generator = dimension_generator.fork();
-            unit_generator.set("unit:name", unit_name);
-            unit_generator.set("unit:acceptable_cpp", make_name_acceptable_cpp(unit_name.to_ascii_lowercase()));
-            unit_generator.append(R"~~~(
-GC::Ref<CSSUnitValue> @unit:acceptable_cpp@(JS::VM& vm, WebIDL::Double value)
-{
-    return numeric_factory(vm, value, "@unit:name@"_fly_string);
-}
-)~~~");
-        });
-    });
-
-    generator.append(R"~~~(
-}
-)~~~");
-
-    TRY(file.write_until_depleted(generator.as_string_view().bytes()));
-    return {};
-}
-
-ErrorOr<void> generate_idl_file(JsonObject& units_data, Core::File& file)
-{
-    StringBuilder builder;
-    SourceGenerator generator { builder };
-
-    generator.append(R"~~~(
-partial namespace CSS {
-    CSSUnitValue number(double value);
-    CSSUnitValue percent(double value);
-
-)~~~");
-
-    units_data.for_each_member([&](auto& dimension_name, JsonValue const& dimension) {
-        auto dimension_generator = generator.fork();
-        dimension_generator.set("dimension:acceptable_cpp", make_name_acceptable_cpp(snake_casify(dimension_name, TrimLeadingUnderscores::Yes)));
-        dimension_generator.append(R"~~~(
-    // <@dimension:acceptable_cpp@>
-)~~~");
-
-        dimension.as_object().for_each_member([&](auto& unit_name, JsonValue const&) {
-            auto unit_generator = dimension_generator.fork();
-            unit_generator.set("unit:name", unit_name);
-            unit_generator.set("unit:acceptable_cpp", make_name_acceptable_cpp(unit_name.to_ascii_lowercase()));
-            unit_generator.appendln("    [ImplementedAs=@unit:acceptable_cpp@] CSSUnitValue @unit:name@(double value);");
-        });
-    });
-
-    generator.append(R"~~~(
-};
-)~~~");
-
-    TRY(file.write_until_depleted(generator.as_string_view().bytes()));
-    return {};
-}

Meta/Utils/utils.py

@@ -78,3 +78,9 @@ def underlying_type_for_enum(member_count: int) -> str:
     if member_count <= 0xFFFFFFFF:
         return "u32"
     return "u64"
+
+
+def make_name_acceptable_cpp(name: str) -> str:
+    if name == "float":
+        return "float_"
+    return name