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Added extra bool in Window object to know about its Mutation Observers

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nupurbaghel committed Feb 13, 2018
1 parent 7945dff commit a1fd6c39a213fbe50db4138304c8cccbfa196486
Showing with 64 additions and 1 deletion.
  1. +5 −1 components/script/dom/mutationobserver.rs
  2. +12 −0 components/script/dom/window.rs
  3. +47 −0 tests/html/mut_observer_perf.html
@@ -9,7 +9,7 @@ use dom::bindings::codegen::Bindings::MutationObserverBinding::MutationCallback;
use dom::bindings::codegen::Bindings::MutationObserverBinding::MutationObserverBinding::MutationObserverMethods;
use dom::bindings::codegen::Bindings::MutationObserverBinding::MutationObserverInit;
use dom::bindings::error::{Error, Fallible};
use dom::bindings::reflector::{Reflector, reflect_dom_object};
use dom::bindings::reflector::{Reflector, reflect_dom_object, DomObject};
use dom::bindings::root::DomRoot;
use dom::bindings::str::DOMString;
use dom::mutationrecord::MutationRecord;
@@ -67,6 +67,7 @@ impl MutationObserver {
}

pub fn Constructor(global: &Window, callback: Rc<MutationCallback>) -> Fallible<DomRoot<MutationObserver>> {
global.set_exists_mut_observer();
let observer = MutationObserver::new(global, callback);
ScriptThread::add_mutation_observer(&*observer);
Ok(observer)
@@ -105,6 +106,9 @@ impl MutationObserver {

/// <https://dom.spec.whatwg.org/#queueing-a-mutation-record>
pub fn queue_a_mutation_record(target: &Node, attr_type: Mutation) {
if !target.global().as_window().get_exists_mut_observer() {
return;
}
// Step 1
let mut interestedObservers: Vec<(DomRoot<MutationObserver>, Option<DOMString>)> = vec![];
// Step 2 & 3
@@ -285,9 +285,20 @@ pub struct Window {
/// The Webrender Document id associated with this window.
#[ignore_malloc_size_of = "defined in webrender_api"]
webrender_document: DocumentId,

/// Flag to identify whether mutation observers are present(true)/absent(false)
exists_mut_observer: Cell<bool>,
}

impl Window {
pub fn get_exists_mut_observer(&self) -> bool {
self.exists_mut_observer.get()
}

pub fn set_exists_mut_observer(&self) {
self.exists_mut_observer.set(true);
}

#[allow(unsafe_code)]
pub fn clear_js_runtime_for_script_deallocation(&self) {
unsafe {
@@ -1814,6 +1825,7 @@ impl Window {
test_worklet: Default::default(),
paint_worklet: Default::default(),
webrender_document,
exists_mut_observer: Cell::new(false),
});

unsafe {
@@ -0,0 +1,47 @@
<!DOCTYPE html>
<html>
<head>
<meta charset='utf-8'>
</head>
<body>
<script>
window.onload = function(){
var script = document.createElement("script");
script.setAttribute("attr", "val");
var start_test = function(targetNode,attr) {
var start = performance.now();
for( val = 1; val <= 1000; val++) {
targetNode.setAttribute(attr, val);
}
var stop = performance.now();
console.log('Time taken:'+ (stop - start)/1000.0);
};
var config = { attributes: true, childList: true };
console.log('Mutation Observer Algorithm performance testing...');
console.log('\nMutation performed without observer ->');
start_test(script,"attr");
console.log('\nMutation performed with observer ->');
var callback = function(mutationsList) {
for(var mutation of mutationsList) {
if (mutation.type == 'childList') {
// Uncomment below line to see changes
// console.log('A child node has been added or removed.');
}
else if (mutation.type == 'attributes') {
// Uncomment below line to see changes
// console.log('The ' + mutation.attributeName + ' attribute was modified.');
}
}
};
var observer = new MutationObserver(callback);
observer.observe(script, config);
start_test(script,"attr");
}
</script>
</body>
</html>

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