Auto merge of #10388 - autrilla:dom-legend-form, r=emilio

Added .form property for legend tag

r? @emilio

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="35" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/10388)
<!-- Reviewable:end -->

components/script/dom/htmllegendelement.rs

@@ -1,12 +1,20 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
+// This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
+// License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+use dom::bindings::codegen::Bindings::ElementBinding::ElementMethods;
 use dom::bindings::codegen::Bindings::HTMLLegendElementBinding;
+use dom::bindings::codegen::Bindings::HTMLLegendElementBinding::HTMLLegendElementMethods;
+use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::document::Document;
+use dom::element::Element;
 use dom::htmlelement::HTMLElement;
-use dom::node::Node;
+use dom::htmlfieldsetelement::HTMLFieldSetElement;
+use dom::htmlformelement::{HTMLFormElement, FormControl};
+use dom::node::{ChildrenMutation, Node, NodeDamage, UnbindContext};
+use dom::virtualmethods::VirtualMethods;
 use string_cache::Atom;
 use util::str::DOMString;
 
@@ -18,18 +26,60 @@ pub struct HTMLLegendElement {
 impl HTMLLegendElement {
     fn new_inherited(localName: Atom,
                      prefix: Option<DOMString>,
-                     document: &Document) -> HTMLLegendElement {
+                     document: &Document)
-        HTMLLegendElement {
+                     -> HTMLLegendElement {
-            htmlelement:
+        HTMLLegendElement { htmlelement: HTMLElement::new_inherited(localName, prefix, document) }
-                HTMLElement::new_inherited(localName, prefix, document)
-        }
     }
 
     #[allow(unrooted_must_root)]
     pub fn new(localName: Atom,
                prefix: Option<DOMString>,
-               document: &Document) -> Root<HTMLLegendElement> {
+               document: &Document)
+               -> Root<HTMLLegendElement> {
         let element = HTMLLegendElement::new_inherited(localName, prefix, document);
         Node::reflect_node(box element, document, HTMLLegendElementBinding::Wrap)
     }
 }
+
+impl VirtualMethods for HTMLLegendElement {
+    fn super_type(&self) -> Option<&VirtualMethods> {
+        Some(self.upcast::<HTMLElement>() as &VirtualMethods)
+    }
+
+    fn bind_to_tree(&self, tree_in_doc: bool) {
+        if let Some(ref s) = self.super_type() {
+            s.bind_to_tree(tree_in_doc);
+        }
+
+        self.upcast::<Element>().check_ancestors_disabled_state_for_form_control();
+    }
+
+    fn unbind_from_tree(&self, context: &UnbindContext) {
+        self.super_type().unwrap().unbind_from_tree(context);
+
+        let node = self.upcast::<Node>();
+        let el = self.upcast::<Element>();
+        if node.ancestors().any(|ancestor| ancestor.is::<HTMLFieldSetElement>()) {
+            el.check_ancestors_disabled_state_for_form_control();
+        } else {
+            el.check_disabled_attribute();
+        }
+    }
+}
+
+
+impl HTMLLegendElementMethods for HTMLLegendElement {
+    // https://html.spec.whatwg.org/multipage/#dom-legend-form
+    fn GetForm(&self) -> Option<Root<HTMLFormElement>> {
+        let parent = match self.upcast::<Node>().GetParentElement() {
+            Some(parent) => parent,
+            None => return None,
+        };
+        if parent.is::<HTMLFieldSetElement>() {
+            return self.form_owner();
+        }
+        None
+    }
+}
+
+impl FormControl for HTMLLegendElement {}

components/script/dom/webidls/HTMLLegendElement.webidl

@@ -5,7 +5,7 @@
 
 // https://html.spec.whatwg.org/multipage/#htmllegendelement
 interface HTMLLegendElement : HTMLElement {
-  //readonly attribute HTMLFormElement? form;
+  readonly attribute HTMLFormElement? form;
 
   // also has obsolete members
 };

tests/wpt/metadata/html/dom/interfaces.html.ini

@@ -5319,15 +5319,9 @@
   [HTMLFieldSetElement interface: operation setCustomValidity(DOMString)]
     expected: FAIL
 
-  [HTMLLegendElement interface: attribute form]
-    expected: FAIL
-
   [HTMLLegendElement interface: attribute align]
     expected: FAIL
 
-  [HTMLLegendElement interface: document.createElement("legend") must inherit property "form" with the proper type (0)]
-    expected: FAIL
-
   [HTMLLegendElement interface: document.createElement("legend") must inherit property "align" with the proper type (1)]
     expected: FAIL
 

tests/wpt/metadata/html/semantics/forms/the-legend-element/legend-form.html.ini

@@ -1,5 +0,0 @@
-[legend-form.html]
-  type: testharness
-  [Check if legend.form return null when legend has no fieldset element as its parent]
-    expected: FAIL
-

tests/wpt/web-platform-tests/html/semantics/forms/the-legend-element/legend-form.html

@@ -13,11 +13,21 @@
   </form>
 </div>
 
+<div style="display:none">
+  <form id="testformWithFieldSet">
+    <fieldset>
+    <legend id="legendWithFieldSet">radio</legend>
+    </fieldset>
+  </form>
+</div>
 <script>
-
+test(function () {
+  var legendEle = document.getElementById("legendWithFieldSet");
+  assert_not_equals(legendEle.form, null);
+  assert_equals(legendEle.form, document.getElementById("testformWithFieldSet"));
+}, "Check if legend.form returns its parent when it's inside a fieldset");
 test(function () {
   var legendEle = document.getElementById("testlegend");
   assert_equals(legendEle.form, null);
 }, "Check if legend.form return null when legend has no fieldset element as its parent");
-
 </script>