servo: Merge #16933 - Implement MutationObserver childList mutations (from MortimerGoro:mutation_children); r=jdm

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Implement MutationObserver childList mutations

---
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- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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Source-Repo: https://github.com/servo/servo
Source-Revision: 323760f47e79b49ef8db4484cca1969bc26b5413

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : d0d805444965d50fc48b8982521415f4ce30c7f8

servo/components/script/dom/mutationobserver.rs

@@ -29,9 +29,10 @@ pub struct MutationObserver {
     record_queue: DOMRefCell<Vec<Root<MutationRecord>>>,
 }
 
-#[derive(Clone)]
-pub enum Mutation {
-    Attribute { name: LocalName, namespace: Namespace, old_value: DOMString }
+pub enum Mutation<'a> {
+    Attribute { name: LocalName, namespace: Namespace, old_value: DOMString },
+    ChildList { added: Option<&'a [&'a Node]>, removed: Option<&'a [&'a Node]>,
+                prev: Option<&'a Node>, next: Option<&'a Node> },
 }
 
 #[derive(HeapSizeOf, JSTraceable)]
@@ -143,6 +144,12 @@ impl MutationObserver {
                             interestedObservers.push((Root::from_ref(&*registered.observer),
                                                       paired_string));
                         }
+                    },
+                    Mutation::ChildList { .. } => {
+                        if !registered.options.child_list {
+                            continue;
+                        }
+                        interestedObservers.push((Root::from_ref(&*registered.observer), None));
                     }
                 }
             }
@@ -159,6 +166,9 @@ impl MutationObserver {
                         None
                     };
                     MutationRecord::attribute_mutated(target, name, namespace, paired_string.clone())
+                },
+                Mutation::ChildList { ref added, ref removed, ref next, ref prev } => {
+                    MutationRecord::child_list_mutated(target, *added, *removed, *next, *prev)
                 }
             };
             // Step 4.8

servo/components/script/dom/mutationrecord.rs

@@ -4,7 +4,7 @@
 
 use dom::bindings::codegen::Bindings::MutationRecordBinding::MutationRecordBinding;
 use dom::bindings::codegen::Bindings::MutationRecordBinding::MutationRecordBinding::MutationRecordMethods;
-use dom::bindings::js::{JS, Root};
+use dom::bindings::js::{JS, MutNullableJS, Root};
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::node::{Node, window_from_node};
@@ -20,6 +20,10 @@ pub struct MutationRecord {
     attribute_name: Option<DOMString>,
     attribute_namespace: Option<DOMString>,
     old_value: Option<DOMString>,
+    added_nodes: MutNullableJS<NodeList>,
+    removed_nodes: MutNullableJS<NodeList>,
+    next_sibling: Option<JS<Node>>,
+    prev_sibling: Option<JS<Node>>,
 }
 
 impl MutationRecord {
@@ -32,15 +36,40 @@ impl MutationRecord {
                                                        target,
                                                        Some(DOMString::from(&**attribute_name)),
                                                        attribute_namespace.map(|n| DOMString::from(&**n)),
-                                                       old_value);
+                                                       old_value,
+                                                       None, None, None, None);
         reflect_dom_object(record, &*window_from_node(target), MutationRecordBinding::Wrap)
     }
 
+    pub fn child_list_mutated(target: &Node,
+                              added_nodes: Option<&[&Node]>,
+                              removed_nodes: Option<&[&Node]>,
+                              next_sibling: Option<&Node>,
+                              prev_sibling: Option<&Node>) -> Root<MutationRecord> {
+        let window = window_from_node(target);
+        let added_nodes = added_nodes.map(|list| NodeList::new_simple_list_slice(&window, list));
+        let removed_nodes = removed_nodes.map(|list| NodeList::new_simple_list_slice(&window, list));
+
+        reflect_dom_object(box MutationRecord::new_inherited("childList",
+                                                             target,
+                                                             None, None, None,
+                                                             added_nodes.as_ref().map(|list| &**list),
+                                                             removed_nodes.as_ref().map(|list| &**list),
+                                                             next_sibling,
+                                                             prev_sibling),
+                           &*window,
+                           MutationRecordBinding::Wrap)
+    }
+
     fn new_inherited(record_type: &str,
                      target: &Node,
                      attribute_name: Option<DOMString>,
                      attribute_namespace: Option<DOMString>,
-                     old_value: Option<DOMString>) -> MutationRecord {
+                     old_value: Option<DOMString>,
+                     added_nodes: Option<&NodeList>,
+                     removed_nodes: Option<&NodeList>,
+                     next_sibling: Option<&Node>,
+                     prev_sibling: Option<&Node>) -> MutationRecord {
         MutationRecord {
             reflector_: Reflector::new(),
             record_type: DOMString::from(record_type),
@@ -48,6 +77,10 @@ impl MutationRecord {
             attribute_name: attribute_name,
             attribute_namespace: attribute_namespace,
             old_value: old_value,
+            added_nodes: MutNullableJS::new(added_nodes),
+            removed_nodes: MutNullableJS::new(removed_nodes),
+            next_sibling: next_sibling.map(JS::from_ref),
+            prev_sibling: prev_sibling.map(JS::from_ref),
         }
     }
 }
@@ -80,24 +113,28 @@ impl MutationRecordMethods for MutationRecord {
 
     // https://dom.spec.whatwg.org/#dom-mutationrecord-addednodes
     fn AddedNodes(&self) -> Root<NodeList> {
-        let window = window_from_node(&*self.target);
-        NodeList::empty(&window)
+        self.added_nodes.or_init(|| {
+            let window = window_from_node(&*self.target);
+            NodeList::empty(&window)
+        })
     }
 
     // https://dom.spec.whatwg.org/#dom-mutationrecord-removednodes
     fn RemovedNodes(&self) -> Root<NodeList> {
-        let window = window_from_node(&*self.target);
-        NodeList::empty(&window)
+        self.removed_nodes.or_init(|| {
+            let window = window_from_node(&*self.target);
+            NodeList::empty(&window)
+        })
     }
 
     // https://dom.spec.whatwg.org/#dom-mutationrecord-previoussibling
     fn GetPreviousSibling(&self) -> Option<Root<Node>> {
-        None
+        self.prev_sibling.as_ref().map(|node| Root::from_ref(&**node))
     }
 
     // https://dom.spec.whatwg.org/#dom-mutationrecord-previoussibling
     fn GetNextSibling(&self) -> Option<Root<Node>> {
-        None
+        self.next_sibling.as_ref().map(|node| Root::from_ref(&**node))
     }
 
 }

servo/components/script/dom/node.rs

@@ -47,7 +47,7 @@ use dom::htmllinkelement::HTMLLinkElement;
 use dom::htmlmetaelement::HTMLMetaElement;
 use dom::htmlstyleelement::HTMLStyleElement;
 use dom::htmltextareaelement::{HTMLTextAreaElement, LayoutHTMLTextAreaElementHelpers};
-use dom::mutationobserver::RegisteredObserver;
+use dom::mutationobserver::{Mutation, MutationObserver, RegisteredObserver};
 use dom::nodelist::NodeList;
 use dom::processinginstruction::ProcessingInstruction;
 use dom::range::WeakRangeVec;
@@ -1616,18 +1616,27 @@ impl Node {
         let new_nodes = if let NodeTypeId::DocumentFragment = node.type_id() {
             // Step 3.
             new_nodes.extend(node.children().map(|kid| JS::from_ref(&*kid)));
-            // Step 4: mutation observers.
-            // Step 5.
+            // Step 4.
             for kid in new_nodes.r() {
                 Node::remove(*kid, node, SuppressObserver::Suppressed);
             }
+            // Step 5.
             vtable_for(&node).children_changed(&ChildrenMutation::replace_all(new_nodes.r(), &[]));
+
+            let mutation = Mutation::ChildList {
+                added: None,
+                removed: Some(new_nodes.r()),
+                prev: None,
+                next: None,
+            };
+            MutationObserver::queue_a_mutation_record(&node, mutation);
+
             new_nodes.r()
         } else {
             // Step 3.
             ref_slice(&node)
         };
-        // Step 6: mutation observers.
+        // Step 6.
         let previous_sibling = match suppress_observers {
             SuppressObserver::Unsuppressed => {
                 match child {
@@ -1646,6 +1655,14 @@ impl Node {
         if let SuppressObserver::Unsuppressed = suppress_observers {
             vtable_for(&parent).children_changed(
                 &ChildrenMutation::insert(previous_sibling.r(), new_nodes, child));
+
+            let mutation = Mutation::ChildList {
+                added: Some(new_nodes),
+                removed: None,
+                prev: previous_sibling.r(),
+                next: child,
+            };
+            MutationObserver::queue_a_mutation_record(&parent, mutation);
         }
     }
 
@@ -1677,9 +1694,19 @@ impl Node {
         if let Some(node) = node {
             Node::insert(node, parent, None, SuppressObserver::Suppressed);
         }
-        // Step 6: mutation observers.
+        // Step 6.
         vtable_for(&parent).children_changed(
             &ChildrenMutation::replace_all(removed_nodes.r(), added_nodes));
+
+        if !removed_nodes.is_empty() || !added_nodes.is_empty() {
+            let mutation = Mutation::ChildList {
+                added: Some(added_nodes),
+                removed: Some(removed_nodes.r()),
+                prev: None,
+                next: None,
+            };
+            MutationObserver::queue_a_mutation_record(&parent, mutation);
+        }
     }
 
     // https://dom.spec.whatwg.org/#concept-node-pre-remove
@@ -1730,6 +1757,15 @@ impl Node {
                 &ChildrenMutation::replace(old_previous_sibling.r(),
                                            &Some(&node), &[],
                                            old_next_sibling.r()));
+
+            let removed = [node];
+            let mutation = Mutation::ChildList {
+                added: None,
+                removed: Some(&removed),
+                prev: old_previous_sibling.r(),
+                next: old_next_sibling.r(),
+            };
+            MutationObserver::queue_a_mutation_record(&parent, mutation);
         }
     }
 
@@ -2182,6 +2218,14 @@ impl NodeMethods for Node {
             &ChildrenMutation::replace(previous_sibling.r(),
                                        &removed_child, nodes,
                                        reference_child));
+        let removed = removed_child.map(|r| [r]);
+        let mutation = Mutation::ChildList {
+            added: Some(nodes),
+            removed: removed.as_ref().map(|r| &r[..]),
+            prev: previous_sibling.r(),
+            next: reference_child,
+        };
+        MutationObserver::queue_a_mutation_record(&self, mutation);
 
         // Step 15.
         Ok(Root::from_ref(child))

servo/components/script/dom/nodelist.rs

@@ -47,6 +47,10 @@ impl NodeList {
         NodeList::new(window, NodeListType::Simple(iter.map(|r| JS::from_ref(&*r)).collect()))
     }
 
+    pub fn new_simple_list_slice(window: &Window, slice: &[&Node]) -> Root<NodeList> {
+        NodeList::new(window, NodeListType::Simple(slice.iter().map(|r| JS::from_ref(*r)).collect()))
+    }
+
     pub fn new_child_list(window: &Window, node: &Node) -> Root<NodeList> {
         NodeList::new(window, NodeListType::Children(ChildrenList::new(node)))
     }