LibWeb: Support interfaces with the [Global] extended attribute

These are treated differently as the interface members are placed on the
object itself, not its prototype.
As the object itself still needs to be hand-written code, and we can no
longer fully hide the gnarly generated code in the prototype object,
these now generate a 'mixin' class that is added to the actual object
through inheritance.

https://webidl.spec.whatwg.org/#Global

Meta/CMake/libweb_generators.cmake

@@ -76,7 +76,7 @@ endfunction()
 function (generate_js_bindings target)
     set(LIBWEB_INPUT_FOLDER "${CMAKE_CURRENT_SOURCE_DIR}")
     function(libweb_js_bindings class)
-        cmake_parse_arguments(PARSE_ARGV 1 LIBWEB_BINDINGS "ITERABLE" "" "")
+        cmake_parse_arguments(PARSE_ARGV 1 LIBWEB_BINDINGS "ITERABLE;GLOBAL" "" "")
         get_filename_component(basename "${class}" NAME)
         set(BINDINGS_SOURCES
             "Bindings/${basename}Constructor.h"
@@ -102,6 +102,19 @@ function (generate_js_bindings target)
                 iterator-prototype-implementation
             )
         endif()
+
+        # FIXME: Instead of requiring a manual declaration of global object bindings, we should ask BindingsGenerator if it's global
+        if(LIBWEB_BINDINGS_GLOBAL)
+            list(APPEND BINDINGS_SOURCES
+                "Bindings/${basename}GlobalMixin.h"
+                "Bindings/${basename}GlobalMixin.cpp"
+            )
+            list(APPEND BINDINGS_TYPES
+                global-mixin-header
+                global-mixin-implementation
+            )
+        endif()
+
         target_sources(${target} PRIVATE ${BINDINGS_SOURCES})
         # FIXME: cmake_minimum_required(3.17) for ZIP_LISTS
         list(LENGTH BINDINGS_SOURCES num_bindings)

Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/main.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
- * Copyright (c) 2021-2022, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2021-2023, Linus Groh <linusg@serenityos.org>
  * Copyright (c) 2021, Luke Wilde <lukew@serenityos.org>
  * Copyright (c) 2022, Ali Mohammad Pur <mpfard@serenityos.org>
  *
@@ -24,6 +24,8 @@ void generate_prototype_header(IDL::Interface const&, StringBuilder&);
 void generate_prototype_implementation(IDL::Interface const&, StringBuilder&);
 void generate_iterator_prototype_header(IDL::Interface const&, StringBuilder&);
 void generate_iterator_prototype_implementation(IDL::Interface const&, StringBuilder&);
+void generate_global_mixin_header(IDL::Interface const&, StringBuilder&);
+void generate_global_mixin_implementation(IDL::Interface const&, StringBuilder&);
 }
 
 ErrorOr<int> serenity_main(Main::Arguments arguments)
@@ -40,12 +42,16 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     bool prototype_implementation_mode = false;
     bool iterator_prototype_header_mode = false;
     bool iterator_prototype_implementation_mode = false;
+    bool global_mixin_header_mode = false;
+    bool global_mixin_implementation_mode = false;
     args_parser.add_option(constructor_header_mode, "Generate the constructor .h file", "constructor-header", 'C');
     args_parser.add_option(constructor_implementation_mode, "Generate the constructor .cpp file", "constructor-implementation", 'O');
     args_parser.add_option(prototype_header_mode, "Generate the prototype .h file", "prototype-header", 'P');
     args_parser.add_option(prototype_implementation_mode, "Generate the prototype .cpp file", "prototype-implementation", 'R');
     args_parser.add_option(iterator_prototype_header_mode, "Generate the iterator prototype .h file", "iterator-prototype-header", 0);
     args_parser.add_option(iterator_prototype_implementation_mode, "Generate the iterator prototype .cpp file", "iterator-prototype-implementation", 0);
+    args_parser.add_option(global_mixin_header_mode, "Generate the global object mixin .h file", "global-mixin-header", 0);
+    args_parser.add_option(global_mixin_implementation_mode, "Generate the global object mixin .cpp file", "global-mixin-implementation", 0);
     args_parser.add_option(Core::ArgsParser::Option {
         .argument_mode = Core::ArgsParser::OptionArgumentMode::Required,
         .help_string = "Add a header search path passed to the compiler",
@@ -148,6 +154,12 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     if (iterator_prototype_implementation_mode)
         IDL::generate_iterator_prototype_implementation(interface, output_builder);
 
+    if (global_mixin_header_mode)
+        IDL::generate_global_mixin_header(interface, output_builder);
+
+    if (global_mixin_implementation_mode)
+        IDL::generate_global_mixin_implementation(interface, output_builder);
+
     TRY(output_file->write(output_builder.string_view().bytes()));
 
     if (!depfile_path.is_null()) {

Userland/Libraries/LibIDL/IDLParser.cpp

@@ -595,6 +595,7 @@ void Parser::parse_interface(Interface& interface)
     interface.constructor_class = DeprecatedString::formatted("{}Constructor", interface.name);
     interface.prototype_class = DeprecatedString::formatted("{}Prototype", interface.name);
     interface.prototype_base_class = DeprecatedString::formatted("{}Prototype", interface.parent_name.is_empty() ? "Object" : interface.parent_name);
+    interface.global_mixin_class = DeprecatedString::formatted("{}GlobalMixin", interface.name);
     consume_whitespace();
 }
 

Userland/Libraries/LibIDL/Types.h

@@ -291,6 +291,7 @@ public:
     DeprecatedString constructor_class;
     DeprecatedString prototype_class;
     DeprecatedString prototype_base_class;
+    DeprecatedString global_mixin_class;
     HashMap<DeprecatedString, HashTable<DeprecatedString>> included_mixins;
 
     DeprecatedString module_own_path;