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Don't run scripts while DOM tree is undergoing mutations (#34505)

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* script: Implement node insertion post-connection hook. Ensure script elements only run scripts when the DOM has stabilized.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* script: Make iframe element use post-connection steps when handling initial document insertion.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* script: Use a delayed task when running post-connection steps.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* script: Add explanatory comment.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Tidy.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>
This commit is contained in:
Josh Matthews 2024-12-26 01:06:09 -05:00 • committed by GitHub
parent 20d67bdc44
commit 981616f918
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GPG key ID: B5690EEEBB952194
10 changed files with 117 additions and 51 deletions
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37
components/script/dom/htmliframeelement.rs
View file

@ -26,7 +26,6 @@ use crate::dom::bindings::cell::DomRefCell;
use crate::dom::bindings::codegen::Bindings::HTMLIFrameElementBinding::HTMLIFrameElementMethods;
use crate::dom::bindings::codegen::Bindings::WindowBinding::Window_Binding::WindowMethods;
use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::refcounted::Trusted;
use crate::dom::bindings::reflector::DomObject;
use crate::dom::bindings::root::{DomRoot, LayoutDom, MutNullableDom};
use crate::dom::bindings::str::{DOMString, USVString};
@ -38,9 +37,7 @@ use crate::dom::element::{
use crate::dom::eventtarget::EventTarget;
use crate::dom::globalscope::GlobalScope;
use crate::dom::htmlelement::HTMLElement;
use crate::dom::node::{
document_from_node, window_from_node, BindContext, Node, NodeDamage, UnbindContext,
};
use crate::dom::node::{document_from_node, window_from_node, Node, NodeDamage, UnbindContext};
use crate::dom::virtualmethods::VirtualMethods;
use crate::dom::windowproxy::WindowProxy;
use crate::script_runtime::CanGc;
@ -741,28 +738,22 @@ impl VirtualMethods for HTMLIFrameElement {
}
}
fn bind_to_tree(&self, context: &BindContext) {
fn post_connection_steps(&self) {
if let Some(s) = self.super_type() {
s.bind_to_tree(context);
s.post_connection_steps();
}
let tree_connected = context.tree_connected;
let iframe = Trusted::new(self);
document_from_node(self).add_delayed_task(task!(IFrameDelayedInitialize: move || {
let this = iframe.root();
// https://html.spec.whatwg.org/multipage/#the-iframe-element
// "When an iframe element is inserted into a document that has
// a browsing context, the user agent must create a new
// browsing context, set the element's nested browsing context
// to the newly-created browsing context, and then process the
// iframe attributes for the "first time"."
if this.upcast::<Node>().is_connected_with_browsing_context() {
debug!("iframe bound to browsing context.");
debug_assert!(tree_connected, "is_connected_with_bc, but not tree_connected");
this.create_nested_browsing_context(CanGc::note());
this.process_the_iframe_attributes(ProcessingMode::FirstTime, CanGc::note());
}
}));
// https://html.spec.whatwg.org/multipage/#the-iframe-element
// "When an iframe element is inserted into a document that has
// a browsing context, the user agent must create a new
// browsing context, set the element's nested browsing context
// to the newly-created browsing context, and then process the
// iframe attributes for the "first time"."
if self.upcast::<Node>().is_connected_with_browsing_context() {
debug!("iframe bound to browsing context.");
self.create_nested_browsing_context(CanGc::note());
self.process_the_iframe_attributes(ProcessingMode::FirstTime, CanGc::note());
}
}
fn unbind_from_tree(&self, context: &UnbindContext) {

27
components/script/dom/htmlscriptelement.rs
View file

@ -55,7 +55,7 @@ use crate::dom::event::{Event, EventBubbles, EventCancelable, EventStatus};
use crate::dom::globalscope::GlobalScope;
use crate::dom::htmlelement::HTMLElement;
use crate::dom::node::{
document_from_node, window_from_node, BindContext, ChildrenMutation, CloneChildrenFlag, Node,
document_from_node, window_from_node, ChildrenMutation, CloneChildrenFlag, Node,
};
use crate::dom::performanceresourcetiming::InitiatorType;
use crate::dom::virtualmethods::VirtualMethods;
@ -1188,25 +1188,32 @@ impl VirtualMethods for HTMLScriptElement {
}
}
/// <https://html.spec.whatwg.org/multipage/#script-processing-model:the-script-element-26>
fn children_changed(&self, mutation: &ChildrenMutation) {
if let Some(s) = self.super_type() {
s.children_changed(mutation);
}
if !self.parser_inserted.get() && self.upcast::<Node>().is_connected() {
self.prepare(CanGc::note());
if self.upcast::<Node>().is_connected() && !self.parser_inserted.get() {
let script = Trusted::new(self);
// This method can be invoked while there are script/layout blockers present
// as DOM mutations have not yet settled. We use a delayed task to avoid
// running any scripts until the DOM tree is safe for interactions.
document_from_node(self).add_delayed_task(task!(ScriptPrepare: move || {
let this = script.root();
this.prepare(CanGc::note());
}));
}
}
fn bind_to_tree(&self, context: &BindContext) {
/// <https://html.spec.whatwg.org/multipage/#script-processing-model:the-script-element-20>
fn post_connection_steps(&self) {
if let Some(s) = self.super_type() {
s.bind_to_tree(context);
s.post_connection_steps();
}
if context.tree_connected && !self.parser_inserted.get() {
let script = Trusted::new(self);
document_from_node(self).add_delayed_task(task!(ScriptDelayedInitialize: move || {
script.root().prepare(CanGc::note());
}));
if self.upcast::<Node>().is_connected() && !self.parser_inserted.get() {
self.prepare(CanGc::note());
}
}

33
components/script/dom/node.rs
View file

@ -68,6 +68,7 @@ use crate::dom::bindings::inheritance::{
Castable, CharacterDataTypeId, ElementTypeId, EventTargetTypeId, HTMLElementTypeId, NodeTypeId,
SVGElementTypeId, SVGGraphicsElementTypeId, TextTypeId,
};
use crate::dom::bindings::refcounted::Trusted;
use crate::dom::bindings::reflector::{reflect_dom_object_with_proto, DomObject, DomObjectWrap};
use crate::dom::bindings::root::{Dom, DomRoot, DomSlice, LayoutDom, MutNullableDom};
use crate::dom::bindings::str::{DOMString, USVString};
@ -2128,6 +2129,38 @@ impl Node {
};
MutationObserver::queue_a_mutation_record(parent, mutation);
}
// Step 10. Let staticNodeList be a list of nodes, initially « ».
let mut static_node_list = vec![];
// Step 11. For each node of nodes, in tree order:
for node in new_nodes {
// Step 11.1 For each shadow-including inclusive descendant inclusiveDescendant of node,
// in shadow-including tree order, append inclusiveDescendant to staticNodeList.
static_node_list.extend(
node.traverse_preorder(ShadowIncluding::Yes)
.map(|n| Trusted::new(&*n)),
);
}
// We use a delayed task for this step to work around an awkward interaction between
// script/layout blockers, Node::replace_all, and the children_changed vtable method.
// Any node with a post connection step that triggers layout (such as iframes) needs
// to be marked as dirty before doing so. This is handled by Node's children_changed
// callback, but when Node::insert is called as part of Node::replace_all then the
// callback is suppressed until we return to Node::replace_all. To ensure the sequence:
// 1) children_changed in Node::replace_all,
// 2) post_connection_steps from Node::insert,
// we use a delayed task that will run as soon as Node::insert removes its
// script/layout blocker.
node.owner_doc().add_delayed_task(task!(PostConnectionSteps: move || {
// Step 12. For each node of staticNodeList, if node is connected, then run the
// post-connection steps with node.
for node in static_node_list.iter().map(Trusted::root).filter(|n| n.is_connected()) {
vtable_for(&node).post_connection_steps();
}
}));
node.owner_doc().remove_script_and_layout_blocker();
}

9
components/script/dom/virtualmethods.rs
View file

@ -93,6 +93,15 @@ pub trait VirtualMethods {
}
}
/// Invoked during a DOM tree mutation after a node becomes connected, once all
/// related DOM tree mutations have been applied.
/// <https://dom.spec.whatwg.org/#concept-node-post-connection-ext>
fn post_connection_steps(&self) {
if let Some(s) = self.super_type() {
s.post_connection_steps();
}
}
/// Called when a Node is appended to a tree, where 'tree_connected' indicates
/// whether the tree is part of a Document.
fn bind_to_tree(&self, context: &BindContext) {