Implement HTMLConstructor

2 files changed, 154 insertions, 11 deletions

diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index 130d2008448..5f60a9fc5fa 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -5301,11 +5301,79 @@ class CGClassConstructHook(CGAbstractExternMethod):
             preamble += "let global = Root::downcast::<dom::types::%s>(global).unwrap();\n" % list(self.exposureSet)[0]
         preamble += """let args = CallArgs::from_vp(vp, argc);\n"""
         preamble = CGGeneric(preamble)
-        name = self.constructor.identifier.name
-        nativeName = MakeNativeName(self.descriptor.binaryNameFor(name))
-        callGenerator = CGMethodCall(["&global"], nativeName, True,
-                                     self.descriptor, self.constructor)
-        return CGList([preamble, callGenerator])
+        if self.constructor.isHTMLConstructor():
+            signatures = self.constructor.signatures()
+            assert len(signatures) == 1
+            constructorCall = CGGeneric("""\
+// Step 2 https://html.spec.whatwg.org/multipage/#htmlconstructor
+// The custom element definition cannot use an element interface as its constructor
+
+// The new_target might be a cross-compartment wrapper. Get the underlying object
+// so we can do the spec's object-identity checks.
+rooted!(in(cx) let new_target = UnwrapObject(args.new_target().to_object(), 1));
+if new_target.is_null() {
+    throw_dom_exception(cx, global.upcast::<GlobalScope>(), Error::Type("new.target is null".to_owned()));
+    return false;
+}
+
+if args.callee() == new_target.get() {
+    throw_dom_exception(cx, global.upcast::<GlobalScope>(),
+        Error::Type("new.target must not be the active function object".to_owned()));
+    return false;
+}
+
+// Step 6
+rooted!(in(cx) let mut prototype = ptr::null_mut());
+{
+    rooted!(in(cx) let mut proto_val = UndefinedValue());
+    let _ac = JSAutoCompartment::new(cx, new_target.get());
+    if !JS_GetProperty(cx, new_target.handle(), b"prototype\\0".as_ptr() as *const _, proto_val.handle_mut()) {
+        return false;
+    }
+
+    if !proto_val.is_object() {
+        // Step 7 of https://html.spec.whatwg.org/multipage/#htmlconstructor.
+        // This fallback behavior is designed to match analogous behavior for the
+        // JavaScript built-ins. So we enter the compartment of our underlying
+        // newTarget object and fall back to the prototype object from that global.
+        // XXX The spec says to use GetFunctionRealm(), which is not actually
+        // the same thing as what we have here (e.g. in the case of scripted callable proxies
+        // whose target is not same-compartment with the proxy, or bound functions, etc).
+        // https://bugzilla.mozilla.org/show_bug.cgi?id=1317658
+
+        rooted!(in(cx) let global_object = CurrentGlobalOrNull(cx));
+        GetProtoObject(cx, global_object.handle(), prototype.handle_mut());
+    } else {
+        // Step 6
+        prototype.set(proto_val.to_object());
+    };
+}
+
+// Wrap prototype in this context since it is from the newTarget compartment
+if !JS_WrapObject(cx, prototype.handle_mut()) {
+    return false;
+}
+
+let result: Result<Root<%s>, Error> = html_constructor(&global, &args);
+let result = match result {
+    Ok(result) => result,
+    Err(e) => {
+        throw_dom_exception(cx, global.upcast::<GlobalScope>(), e);
+        return false;
+    },
+};
+
+JS_SetPrototype(cx, result.reflector().get_jsobject(), prototype.handle());
+
+(result).to_jsval(cx, args.rval());
+return true;
+""" % self.descriptor.name)
+        else:
+            name = self.constructor.identifier.name
+            nativeName = MakeNativeName(self.descriptor.binaryNameFor(name))
+            constructorCall = CGMethodCall(["&global"], nativeName, True,
+                                           self.descriptor, self.constructor)
+        return CGList([preamble, constructorCall])
 
 
 class CGClassFinalizeHook(CGAbstractClassHook):
@@ -5517,9 +5585,11 @@ def generate_imports(config, cgthings, descriptors, callbacks=None, dictionaries
         'js::jsapi::JS_ObjectIsDate',
         'js::jsapi::JS_SetImmutablePrototype',
         'js::jsapi::JS_SetProperty',
+        'js::jsapi::JS_SetPrototype',
         'js::jsapi::JS_SetReservedSlot',
         'js::jsapi::JS_SplicePrototype',
         'js::jsapi::JS_WrapValue',
+        'js::jsapi::JS_WrapObject',
         'js::jsapi::MutableHandle',
         'js::jsapi::MutableHandleObject',
         'js::jsapi::MutableHandleValue',
@@ -5547,6 +5617,7 @@ def generate_imports(config, cgthings, descriptors, callbacks=None, dictionaries
         'js::glue::RUST_JSID_IS_STRING',
         'js::glue::RUST_SYMBOL_TO_JSID',
         'js::glue::int_to_jsid',
+        'js::glue::UnwrapObject',
         'js::panic::maybe_resume_unwind',
         'js::panic::wrap_panic',
         'js::rust::GCMethods',
@@ -5561,14 +5632,15 @@ def generate_imports(config, cgthings, descriptors, callbacks=None, dictionaries
         'dom::bindings::interface::ConstructorClassHook',
         'dom::bindings::interface::InterfaceConstructorBehavior',
         'dom::bindings::interface::NonCallbackInterfaceObjectClass',
-        'dom::bindings::interface::create_callback_interface_object',
         'dom::bindings::interface::create_global_object',
+        'dom::bindings::interface::create_callback_interface_object',
         'dom::bindings::interface::create_interface_prototype_object',
         'dom::bindings::interface::create_named_constructors',
         'dom::bindings::interface::create_noncallback_interface_object',
         'dom::bindings::interface::define_guarded_constants',
         'dom::bindings::interface::define_guarded_methods',
         'dom::bindings::interface::define_guarded_properties',
+        'dom::bindings::interface::html_constructor',
         'dom::bindings::interface::is_exposed_in',
         'dom::bindings::iterable::Iterable',
         'dom::bindings::iterable::IteratorType',
diff --git a/components/script/dom/bindings/interface.rs b/components/script/dom/bindings/interface.rs
index 33ce8954c62..752917aa673 100644
--- a/components/script/dom/bindings/interface.rs
+++ b/components/script/dom/bindings/interface.rs
@@ -70,18 +70,26 @@ use dom::bindings::codegen::Bindings::HTMLTitleElementBinding;
 use dom::bindings::codegen::Bindings::HTMLTrackElementBinding;
 use dom::bindings::codegen::Bindings::HTMLUListElementBinding;
 use dom::bindings::codegen::Bindings::HTMLVideoElementBinding;
+use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::InterfaceObjectMap::Globals;
 use dom::bindings::codegen::PrototypeList;
 use dom::bindings::constant::{ConstantSpec, define_constants};
-use dom::bindings::conversions::{DOM_OBJECT_SLOT, get_dom_class};
+use dom::bindings::conversions::{DOM_OBJECT_SLOT, DerivedFrom, get_dom_class};
+use dom::bindings::error::{Error, Fallible};
 use dom::bindings::guard::Guard;
+use dom::bindings::js::Root;
 use dom::bindings::utils::{DOM_PROTOTYPE_SLOT, ProtoOrIfaceArray, get_proto_or_iface_array};
+use dom::create::create_native_html_element;
+use dom::element::{Element, ElementCreator};
+use dom::htmlelement::HTMLElement;
+use dom::window::Window;
 use html5ever::LocalName;
+use html5ever::interface::QualName;
 use js::error::throw_type_error;
-use js::glue::{RUST_SYMBOL_TO_JSID, UncheckedUnwrapObject};
-use js::jsapi::{Class, ClassOps, CompartmentOptions, GetGlobalForObjectCrossCompartment};
-use js::jsapi::{GetWellKnownSymbol, HandleObject, HandleValue, JSAutoCompartment};
-use js::jsapi::{JSClass, JSContext, JSFUN_CONSTRUCTOR, JSFunctionSpec, JSObject};
+use js::glue::{RUST_SYMBOL_TO_JSID, UncheckedUnwrapObject, UnwrapObject};
+use js::jsapi::{CallArgs, Class, ClassOps, CompartmentOptions, CurrentGlobalOrNull};
+use js::jsapi::{GetGlobalForObjectCrossCompartment, GetWellKnownSymbol, HandleObject, HandleValue};
+use js::jsapi::{JSAutoCompartment, JSClass, JSContext, JSFUN_CONSTRUCTOR, JSFunctionSpec, JSObject};
 use js::jsapi::{JSPROP_PERMANENT, JSPROP_READONLY, JSPROP_RESOLVING};
 use js::jsapi::{JSPropertySpec, JSString, JSTracer, JSVersion, JS_AtomizeAndPinString};
 use js::jsapi::{JS_DefineProperty, JS_DefineProperty1, JS_DefineProperty2};
@@ -225,6 +233,69 @@ pub unsafe fn create_global_object(
     JS_FireOnNewGlobalObject(cx, rval.handle());
 }
 
+// https://html.spec.whatwg.org/multipage/#htmlconstructor
+pub unsafe fn html_constructor<T>(window: &Window, call_args: &CallArgs) -> Fallible<Root<T>>
+                                  where T: DerivedFrom<Element> {
+    let document = window.Document();
+
+    // Step 1
+    let registry = window.CustomElements();
+
+    // Step 2 is checked in the generated caller code
+
+    // Step 3
+    rooted!(in(window.get_cx()) let new_target = call_args.new_target().to_object());
+    let definition = match registry.lookup_definition_by_constructor(new_target.handle()) {
+        Some(definition) => definition,
+        None => return Err(Error::Type("No custom element definition found for new.target".to_owned())),
+    };
+
+    rooted!(in(window.get_cx()) let callee = UnwrapObject(call_args.callee(), 1));
+    if callee.is_null() {
+        return Err(Error::Security);
+    }
+
+    {
+        let _ac = JSAutoCompartment::new(window.get_cx(), callee.get());
+
+        if definition.is_autonomous() {
+            // Step 4
+            // Since this element is autonomous, its active function object must be the HTMLElement
+
+            // Retrieve the constructor object for HTMLElement
+            rooted!(in(window.get_cx()) let mut constructor = ptr::null_mut());
+            rooted!(in(window.get_cx()) let global_object = CurrentGlobalOrNull(window.get_cx()));
+            HTMLElementBinding::GetConstructorObject(window.get_cx(), global_object.handle(), constructor.handle_mut());
+
+            // Callee must be the same constructor object as HTMLElement
+            if constructor.get() != callee.get() {
+                return Err(Error::Type("Active function object is not HTMLElement".to_owned()));
+            }
+        } else {
+            // TODO: Step 5
+        }
+    }
+
+    // Step 8.1
+    let name = QualName::new(None, ns!(html), definition.local_name.clone());
+    let element = if definition.is_autonomous() {
+        Root::upcast(HTMLElement::new(name.local, None, &*document))
+    } else {
+        create_native_html_element(name, None, &*document, ElementCreator::ScriptCreated)
+    };
+
+    // Step 8.2 is performed in the generated caller code.
+
+    // TODO: Step 8.3 - 8.4
+    // Set the element's custom element state and definition.
+
+    // Step 8.5
+    Root::downcast(element).ok_or(Error::InvalidState)
+
+    // TODO: Steps 9-13
+    // Custom element upgrades are not implemented yet, so these steps are unnecessary.
+}
+
 /// Create and define the interface object of a callback interface.
 pub unsafe fn create_callback_interface_object(
         cx: *mut JSContext,