1 files changed, 56 insertions, 1 deletions

diff --git a/components/script/dom/htmlelement.rs b/components/script/dom/htmlelement.rs
index e38ab5ff523..f36e84a078e 100644
--- a/components/script/dom/htmlelement.rs
+++ b/components/script/dom/htmlelement.rs
@@ -13,10 +13,13 @@ use dom::bindings::codegen::InheritTypes::{ElementCast, HTMLFrameSetElementDeriv
 use dom::bindings::codegen::InheritTypes::{EventTargetCast, HTMLInputElementCast};
 use dom::bindings::codegen::InheritTypes::{HTMLElementDerived, HTMLBodyElementDerived};
 use dom::bindings::js::{JSRef, Temporary, MutNullableJS};
+use dom::bindings::error::ErrorResult;
+use dom::bindings::error::Error::Syntax;
 use dom::bindings::utils::{Reflectable, Reflector};
 use dom::cssstyledeclaration::CSSStyleDeclaration;
 use dom::document::Document;
-use dom::element::{Element, ElementTypeId, ActivationElementHelpers};
+use dom::domstringmap::DOMStringMap;
+use dom::element::{Element, ElementTypeId, ActivationElementHelpers, AttributeHandlers};
 use dom::eventtarget::{EventTarget, EventTargetHelpers, EventTargetTypeId};
 use dom::node::{Node, NodeTypeId, window_from_node};
 use dom::virtualmethods::VirtualMethods;
@@ -31,6 +34,7 @@ use std::default::Default;
 pub struct HTMLElement {
     element: Element,
     style_decl: MutNullableJS<CSSStyleDeclaration>,
+    dataset: MutNullableJS<DOMStringMap>,
 }
 
 impl HTMLElementDerived for EventTarget {
@@ -48,6 +52,7 @@ impl HTMLElement {
         HTMLElement {
             element: Element::new_inherited(type_id, tag_name, ns!(HTML), prefix, document),
             style_decl: Default::default(),
+            dataset: Default::default(),
         }
     }
 
@@ -89,6 +94,11 @@ impl<'a> HTMLElementMethods for JSRef<'a, HTMLElement> {
 
     global_event_handlers!(NoOnload)
 
+    // https://html.spec.whatwg.org/multipage/dom.html#dom-dataset
+    fn Dataset(self) -> Temporary<DOMStringMap> {
+        self.dataset.or_init(|| DOMStringMap::new(self))
+    }
+
     fn GetOnload(self) -> Option<EventHandlerNonNull> {
         if self.is_body_or_frameset() {
             let win = window_from_node(self).root();
@@ -122,6 +132,51 @@ impl<'a> HTMLElementMethods for JSRef<'a, HTMLElement> {
     }
 }
 
+// https://html.spec.whatwg.org/#attr-data-*
+pub trait HTMLElementCustomAttributeHelpers {
+    fn set_custom_attr(self, name: DOMString, value: DOMString) -> ErrorResult;
+    fn get_custom_attr(self, name: DOMString) -> Option<DOMString>;
+    fn delete_custom_attr(self, name: DOMString);
+}
+
+fn to_snake_case(name: DOMString) -> DOMString {
+    let mut attr_name = "data-".into_string();
+    for ch in name.as_slice().chars() {
+        if ch.is_uppercase() {
+            attr_name.push('\x2d');
+            attr_name.push(ch.to_lowercase());
+        } else {
+            attr_name.push(ch);
+        }
+    }
+    attr_name
+}
+
+impl<'a> HTMLElementCustomAttributeHelpers for JSRef<'a, HTMLElement> {
+    fn set_custom_attr(self, name: DOMString, value: DOMString) -> ErrorResult {
+        if name.as_slice().chars()
+               .skip_while(|&ch| ch != '\u002d')
+               .nth(1).map_or(false, |ch| ch as u8 - b'a' < 26) {
+            return Err(Syntax);
+        }
+        let element: JSRef<Element> = ElementCast::from_ref(self);
+        element.set_custom_attribute(to_snake_case(name), value)
+    }
+
+    fn get_custom_attr(self, name: DOMString) -> Option<DOMString> {
+        let element: JSRef<Element> = ElementCast::from_ref(self);
+        element.get_attribute(ns!(""), &Atom::from_slice(to_snake_case(name).as_slice())).map(|attr| {
+            let attr = attr.root();
+            attr.value().as_slice().to_string()
+        })
+    }
+
+    fn delete_custom_attr(self, name: DOMString) {
+        let element: JSRef<Element> = ElementCast::from_ref(self);
+        element.remove_attribute(ns!(""), to_snake_case(name).as_slice())
+    }
+}
+
 impl<'a> VirtualMethods for JSRef<'a, HTMLElement> {
     fn super_type<'a>(&'a self) -> Option<&'a VirtualMethods> {
         let element: &JSRef<Element> = ElementCast::from_borrowed_ref(self);