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Labels are a live list in tree order

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This commit is contained in:
Patrick Shaughnessy 2020-01-02 15:44:29 -05:00
parent 0d142bea9a
commit 036e8dabe2
14 changed files with 161 additions and 102 deletions
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70
components/script/dom/htmlelement.rs
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@ -4,10 +4,10 @@
use crate::dom::activation::{synthetic_click_activation, ActivationSource};
use crate::dom::attr::Attr;
use crate::dom::bindings::codegen::Bindings::ElementBinding::ElementMethods;
use crate::dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
use crate::dom::bindings::codegen::Bindings::HTMLElementBinding;
use crate::dom::bindings::codegen::Bindings::HTMLElementBinding::HTMLElementMethods;
use crate::dom::bindings::codegen::Bindings::HTMLLabelElementBinding::HTMLLabelElementMethods;
use crate::dom::bindings::codegen::Bindings::NodeBinding::NodeBinding::NodeMethods;
use crate::dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
use crate::dom::bindings::error::{Error, ErrorResult};
@ -29,7 +29,6 @@ use crate::dom::htmlinputelement::{HTMLInputElement, InputType};
use crate::dom::htmllabelelement::HTMLLabelElement;
use crate::dom::node::{document_from_node, window_from_node};
use crate::dom::node::{BindContext, Node, NodeFlags, ShadowIncluding};
use crate::dom::nodelist::NodeList;
use crate::dom::text::Text;
use crate::dom::virtualmethods::VirtualMethods;
use dom_struct::dom_struct;
@ -677,43 +676,48 @@ impl HTMLElement {
}
// https://html.spec.whatwg.org/multipage/#dom-lfe-labels
pub fn labels(&self) -> DomRoot<NodeList> {
debug_assert!(self.is_labelable_element());
// This gets the nth label in tree order.
pub fn label_at(&self, index: u32) -> Option<DomRoot<Node>> {
let element = self.upcast::<Element>();
let window = window_from_node(element);
// Traverse ancestors for implicitly associated <label> elements
// https://html.spec.whatwg.org/multipage/#the-label-element:attr-label-for-4
let ancestors = self
.upcast::<Node>()
.ancestors()
.filter_map(DomRoot::downcast::<HTMLElement>)
// If we reach a labelable element, we have a guarantee no ancestors above it
// will be a label for this HTMLElement
.take_while(|elem| !elem.is_labelable_element())
.filter_map(DomRoot::downcast::<HTMLLabelElement>)
.filter(|elem| !elem.upcast::<Element>().has_attribute(&local_name!("for")))
.filter(|elem| elem.first_labelable_descendant().as_deref() == Some(self))
.map(DomRoot::upcast::<Node>);
let id = element.Id();
let id = match &id as &str {
"" => return NodeList::new_simple_list(&window, ancestors),
id => id,
};
// Traverse entire tree for <label> elements with `for` attribute matching `id`
// Traverse entire tree for <label> elements that have
// this as their control.
// There is room for performance optimization, as we don't need
// the actual result of GetControl, only whether the result
// would match self.
// (Even more room for performance optimization: do what
// nodelist ChildrenList does and keep a mutation-aware cursor
// around; this may be hard since labels need to keep working
// even as they get detached into a subtree and reattached to
// a document.)
let root_element = element.root_element();
let root_node = root_element.upcast::<Node>();
let children = root_node
root_node
.traverse_preorder(ShadowIncluding::No)
.filter_map(DomRoot::downcast::<Element>)
.filter(|elem| elem.is::<HTMLLabelElement>())
.filter(|elem| elem.get_string_attribute(&local_name!("for")) == id)
.map(DomRoot::upcast::<Node>);
.filter_map(DomRoot::downcast::<HTMLLabelElement>)
.filter(|elem| match elem.GetControl() {
Some(control) => &*control == self,
_ => false,
})
.nth(index as usize)
.map(|n| DomRoot::from_ref(n.upcast::<Node>()))
}
NodeList::new_simple_list(&window, children.chain(ancestors))
// https://html.spec.whatwg.org/multipage/#dom-lfe-labels
// This counts the labels of the element, to support NodeList::Length
pub fn labels_count(&self) -> u32 {
// see label_at comments about performance
let element = self.upcast::<Element>();
let root_element = element.root_element();
let root_node = root_element.upcast::<Node>();
root_node
.traverse_preorder(ShadowIncluding::No)
.filter_map(DomRoot::downcast::<HTMLLabelElement>)
.filter(|elem| match elem.GetControl() {
Some(control) => &*control == self,
_ => false,
})
.count() as u32
}
}