Auto merge of #29798 - jdm:per-interface-codegen, r=jdm

Extract bodies of generated binding helpers into common code

This is part of fixing #29770, by extracting common behaviour that [will be called](https://searchfox.org/mozilla-central/rev/2d678a843ceab81e43f7ffb83212197dc10e944a/dom/bindings/BindingUtils.cpp#3744) from new code in interface.rs.

---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] There are tests for these changes

components/script/dom/bindings/codegen/CodegenRust.py

@@ -3490,24 +3490,12 @@ class CGGetPerInterfaceObject(CGAbstractMethod):
         CGAbstractMethod.__init__(self, descriptor, name,
                                   'void', args, pub=pub)
         self.id = idPrefix + "::" + MakeNativeName(self.descriptor.name)
+        self.variant = self.id.split('::')[-2]
 
     def definition_body(self):
         return CGGeneric("""
-unsafe {
-    assert!(((*get_object_class(global.get())).flags & JSCLASS_DOM_GLOBAL) != 0);
-
-    /* Check to see whether the interface objects are already installed */
-    let proto_or_iface_array = get_proto_or_iface_array(global.get());
-    rval.set((*proto_or_iface_array)[%(id)s as usize]);
-    if !rval.get().is_null() {
-        return;
-    }
-
-    CreateInterfaceObjects(cx, global, proto_or_iface_array);
-    rval.set((*proto_or_iface_array)[%(id)s as usize]);
-    assert!(!rval.get().is_null());
-}
-""" % {"id": self.id})
+        get_per_interface_object_handle(cx, global, ProtoOrIfaceIndex::%s(%s), CreateInterfaceObjects, rval)
+        """ % (self.variant, self.id))
 
 
 class CGGetProtoObjectMethod(CGGetPerInterfaceObject):
@@ -3655,25 +3643,20 @@ class CGDefineDOMInterfaceMethod(CGAbstractMethod):
         ]
         CGAbstractMethod.__init__(self, descriptor, 'DefineDOMInterface',
                                   'void', args, pub=True)
+        if self.descriptor.interface.isCallback() or self.descriptor.interface.isNamespace():
+            idPrefix = "PrototypeList::Constructor"
+        else:
+            idPrefix = "PrototypeList::ID"
+        self.id = idPrefix + "::" + MakeNativeName(self.descriptor.name)
+        self.variant = self.id.split('::')[-2]
 
     def define(self):
         return CGAbstractMethod.define(self)
 
     def definition_body(self):
-        if self.descriptor.interface.isCallback() or self.descriptor.interface.isNamespace():
-            function = "GetConstructorObject"
-        else:
-            function = "GetProtoObject"
-        return CGGeneric("""\
-assert!(!global.get().is_null());
-
-if !ConstructorEnabled(cx, global) {
-    return;
-}
-
-rooted!(in(*cx) let mut proto = ptr::null_mut::<JSObject>());
-%s(cx, global, proto.handle_mut());
-assert!(!proto.is_null());""" % (function,))
+        return CGGeneric("""
+        define_dom_interface(cx, global, ProtoOrIfaceIndex::%s(%s), CreateInterfaceObjects, ConstructorEnabled)
+        """ % (self.variant, self.id))
 
 
 def needCx(returnType, arguments, considerTypes):
@@ -6444,15 +6427,18 @@ def generate_imports(config, cgthings, descriptors, callbacks=None, dictionaries
         'crate::dom::bindings::interface::ConstructorClassHook',
         'crate::dom::bindings::interface::InterfaceConstructorBehavior',
         'crate::dom::bindings::interface::NonCallbackInterfaceObjectClass',
+        'crate::dom::bindings::interface::ProtoOrIfaceIndex',
         'crate::dom::bindings::interface::create_global_object',
         'crate::dom::bindings::interface::create_callback_interface_object',
         'crate::dom::bindings::interface::create_interface_prototype_object',
         'crate::dom::bindings::interface::create_named_constructors',
         'crate::dom::bindings::interface::create_noncallback_interface_object',
+        'crate::dom::bindings::interface::define_dom_interface',
         'crate::dom::bindings::interface::define_guarded_constants',
         'crate::dom::bindings::interface::define_guarded_methods',
         'crate::dom::bindings::interface::define_guarded_properties',
         'crate::dom::bindings::interface::is_exposed_in',
+        'crate::dom::bindings::interface::get_per_interface_object_handle',
         'crate::dom::bindings::htmlconstructor::pop_current_element_queue',
         'crate::dom::bindings::htmlconstructor::push_new_element_queue',
         'crate::dom::bindings::iterable::Iterable',

components/script/dom/bindings/interface.rs

@@ -10,7 +10,9 @@ use crate::dom::bindings::constant::{define_constants, ConstantSpec};
 use crate::dom::bindings::conversions::{get_dom_class, DOM_OBJECT_SLOT};
 use crate::dom::bindings::guard::Guard;
 use crate::dom::bindings::principals::ServoJSPrincipals;
-use crate::dom::bindings::utils::{ProtoOrIfaceArray, DOM_PROTOTYPE_SLOT};
+use crate::dom::bindings::utils::{
+    get_proto_or_iface_array, ProtoOrIfaceArray, DOM_PROTOTYPE_SLOT, JSCLASS_DOM_GLOBAL,
+};
 use crate::script_runtime::JSContext as SafeJSContext;
 use js::error::throw_type_error;
 use js::glue::UncheckedUnwrapObject;
@@ -534,3 +536,59 @@ unsafe extern "C" fn non_new_constructor(
     throw_type_error(cx, "This constructor needs to be called with `new`.");
     false
 }
+
+pub enum ProtoOrIfaceIndex {
+    ID(PrototypeList::ID),
+    Constructor(PrototypeList::Constructor),
+}
+
+impl Into<usize> for ProtoOrIfaceIndex {
+    fn into(self) -> usize {
+        match self {
+            ProtoOrIfaceIndex::ID(id) => id as usize,
+            ProtoOrIfaceIndex::Constructor(constructor) => constructor as usize,
+        }
+    }
+}
+
+pub fn get_per_interface_object_handle(
+    cx: SafeJSContext,
+    global: HandleObject,
+    id: ProtoOrIfaceIndex,
+    creator: unsafe fn(SafeJSContext, HandleObject, *mut ProtoOrIfaceArray),
+    mut rval: MutableHandleObject,
+) {
+    unsafe {
+        assert!(((*get_object_class(global.get())).flags & JSCLASS_DOM_GLOBAL) != 0);
+
+        /* Check to see whether the interface objects are already installed */
+        let proto_or_iface_array = get_proto_or_iface_array(global.get());
+        let index: usize = id.into();
+        rval.set((*proto_or_iface_array)[index]);
+        if !rval.get().is_null() {
+            return;
+        }
+
+        creator(cx, global, proto_or_iface_array);
+        rval.set((*proto_or_iface_array)[index]);
+        assert!(!rval.get().is_null());
+    }
+}
+
+pub fn define_dom_interface(
+    cx: SafeJSContext,
+    global: HandleObject,
+    id: ProtoOrIfaceIndex,
+    creator: unsafe fn(SafeJSContext, HandleObject, *mut ProtoOrIfaceArray),
+    enabled: fn(SafeJSContext, HandleObject) -> bool,
+) {
+    assert!(!global.get().is_null());
+
+    if !enabled(cx, global) {
+        return;
+    }
+
+    rooted!(in(*cx) let mut proto = ptr::null_mut::<JSObject>());
+    get_per_interface_object_handle(cx, global, id, creator, proto.handle_mut());
+    assert!(!proto.is_null());
+}