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Code Issues Releases Wiki Activity

imported mutation observer code from uBlock: more efficient, robust

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gorhill 2014-11-06 10:15:41 -05:00
parent fb9def312a
commit 667becf500
1 changed files with 35 additions and 15 deletions
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50
src/js/contentscript-end.js
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@ -219,7 +219,10 @@ var nodesAddedHandler = function(nodeList, summary) {
var i = 0;
var node, src, text;
while ( node = nodeList.item(i++) ) {
if ( !node.tagName ) {
if ( node.nodeType !== 1 ) {
continue;
}
if ( typeof node.tagName !== 'string' ) {
continue;
}
@ -273,6 +276,10 @@ var nodesAddedHandler = function(nodeList, summary) {
/******************************************************************************/
var nodeListsAddedHandler = function(nodeLists) {
var i = nodeLists.length;
if ( i === 0 ) {
return;
}
var summary = {
what: 'contentScriptSummary',
locationURL: window.location.href,
@ -280,7 +287,6 @@ var nodeListsAddedHandler = function(nodeLists) {
pluginSources: {}, // to avoid duplicates
mustReport: false
};
var i = nodeLists.length;
while ( i-- ) {
nodesAddedHandler(nodeLists[i], summary);
}
@ -330,28 +336,42 @@ if ( /^https?:\/\/./.test(window.location.href) === false ) {
// Observe changes in the DOM
var mutationObservedHandler = function(mutations) {
var i = mutations.length;
var nodeLists = [], nodeList;
while ( i-- ) {
nodeList = mutations[i].addedNodes;
if ( nodeList && nodeList.length ) {
nodeLists.push(nodeList);
// Added node lists will be cumulated here before being processed
var addedNodeLists = [];
var addedNodeListsTimer = null;
var treeMutationObservedHandler = function() {
nodeListsAddedHandler(addedNodeLists);
addedNodeListsTimer = null;
addedNodeLists = [];
};
// https://github.com/gorhill/uBlock/issues/205
// Do not handle added node directly from within mutation observer.
var treeMutationObservedHandlerAsync = function(mutations) {
var iMutation = mutations.length;
var nodeList;
while ( iMutation-- ) {
nodeList = mutations[iMutation].addedNodes;
if ( nodeList.length !== 0 ) {
addedNodeLists.push(nodeList);
}
}
if ( nodeLists.length ) {
nodeListsAddedHandler(nodeLists);
// I arbitrarily chose 250 ms for now:
// I have to compromise between the overhead of processing too few
// nodes too often and the delay of many nodes less often. There is nothing
// time critical here.
if ( addedNodeListsTimer === null ) {
addedNodeListsTimer = setTimeout(treeMutationObservedHandler, 250);
}
};
// This fixes http://acid3.acidtests.org/
if ( document.body ) {
// https://github.com/gorhill/httpswitchboard/issues/176
var observer = new MutationObserver(mutationObservedHandler);
observer.observe(document.body, {
attributes: false,
var treeObserver = new MutationObserver(treeMutationObservedHandlerAsync);
treeObserver.observe(document.body, {
childList: true,
characterData: false,
subtree: true
});
}