LibWeb: Generate dedicated methods to create Web constructors/prototypes

Currently, for each exposed interface, we generate one massive function
to create every Web constructor and prototype. In an effort to lazily
create these instead, this first step is to extract the creation of each
of these into its own method.

First, this generates a forwarding header for all IDL types. This is to
allow callers to remain unchanged without forcing them to include the
(very heavy) generated IDL headers. This header is included by LibWeb's
forwarding header.

Next, this defines a base template method on Web::Bindings::Intrinsics
to create a prototype/constructor pair. Specializations of this template
are now generated in a new .cpp file, IntrinsicDefinitions.cpp. The base
Intrinsics class is updated to use this new method, and will continue to
cache the result.

Last, some WebAssembly classes are updated to use this new mechanism.
They were using some ad hoc cache keys that are now in line with the
generated specializations.

That one massive function is still used to invoke these specializations,
so they are not lazy as of this commit.

1 files changed, 14 insertions, 16 deletions

diff --git a/Userland/Libraries/LibWeb/Bindings/Intrinsics.h b/Userland/Libraries/LibWeb/Bindings/Intrinsics.h
index 610100c185..012278c402 100644
--- a/Userland/Libraries/LibWeb/Bindings/Intrinsics.h
+++ b/Userland/Libraries/LibWeb/Bindings/Intrinsics.h
@@ -27,36 +27,34 @@ public:
 
     JS::Object& cached_web_prototype(DeprecatedString const& class_name);
 
-    template<typename T>
+    template<typename PrototypeType>
     JS::Object& ensure_web_prototype(DeprecatedString const& class_name)
     {
-        auto it = m_prototypes.find(class_name);
-        if (it != m_prototypes.end())
+        if (auto it = m_prototypes.find(class_name); it != m_prototypes.end())
             return *it->value;
-        auto& realm = *m_realm;
-        auto prototype = heap().allocate<T>(realm, realm);
-        m_prototypes.set(class_name, prototype);
-        return prototype;
+
+        create_web_prototype_and_constructor<PrototypeType>(*m_realm);
+        return *m_prototypes.find(class_name)->value;
     }
 
-    template<typename T>
+    template<typename PrototypeType>
     JS::NativeFunction& ensure_web_constructor(DeprecatedString const& class_name)
     {
-        auto it = m_constructors.find(class_name);
-        if (it != m_constructors.end())
+        if (auto it = m_constructors.find(class_name); it != m_constructors.end())
             return *it->value;
-        auto& realm = *m_realm;
-        auto constructor = heap().allocate<T>(realm, realm);
-        m_constructors.set(class_name, constructor);
-        return constructor;
+
+        create_web_prototype_and_constructor<PrototypeType>(*m_realm);
+        return *m_constructors.find(class_name)->value;
     }
 
 private:
     virtual void visit_edges(JS::Cell::Visitor&) override;
 
-    HashMap<DeprecatedString, JS::Object*> m_prototypes;
-    HashMap<DeprecatedString, JS::NativeFunction*> m_constructors;
+    template<typename PrototypeType>
+    void create_web_prototype_and_constructor(JS::Realm& realm);
 
+    HashMap<DeprecatedString, JS::NonnullGCPtr<JS::Object>> m_prototypes;
+    HashMap<DeprecatedString, JS::GCPtr<JS::NativeFunction>> m_constructors;
     JS::NonnullGCPtr<JS::Realm> m_realm;
 };