ref: 1599c124b605bd91542dba27c2deedc163e516a4
dir: /domino-lib/Document.js/
"use strict";
module.exports = Document;
var Node = require('./Node');
var NodeList = require('./NodeList');
var ContainerNode = require('./ContainerNode');
var Element = require('./Element');
var Text = require('./Text');
var Comment = require('./Comment');
var Event = require('./Event');
var DocumentFragment = require('./DocumentFragment');
var ProcessingInstruction = require('./ProcessingInstruction');
var DOMImplementation = require('./DOMImplementation');
var TreeWalker = require('./TreeWalker');
var NodeIterator = require('./NodeIterator');
var NodeFilter = require('./NodeFilter');
var URL = require('./URL');
var select = require('./select');
var events = require('./events');
var xml = require('./xmlnames');
var html = require('./htmlelts');
var svg = require('./svg');
var utils = require('./utils');
var MUTATE = require('./MutationConstants');
var NAMESPACE = utils.NAMESPACE;
var isApiWritable = require("./config").isApiWritable;
function Document(isHTML, address) {
ContainerNode.call(this);
this.nodeType = Node.DOCUMENT_NODE;
this.isHTML = isHTML;
this._address = address || 'about:blank';
this.readyState = 'loading';
this.implementation = new DOMImplementation(this);
// DOMCore says that documents are always associated with themselves
this.ownerDocument = null; // ... but W3C tests expect null
this._contentType = isHTML ? 'text/html' : 'application/xml';
// These will be initialized by our custom versions of
// appendChild and insertBefore that override the inherited
// Node methods.
// XXX: override those methods!
this.doctype = null;
this.documentElement = null;
// "Associated inert template document"
this._templateDocCache = null;
// List of active NodeIterators, see NodeIterator#_preremove()
this._nodeIterators = null;
// Documents are always rooted, by definition
this._nid = 1;
this._nextnid = 2; // For numbering children of the document
this._nodes = [null, this]; // nid to node map
// This maintains the mapping from element ids to element nodes.
// We may need to update this mapping every time a node is rooted
// or uprooted, and any time an attribute is added, removed or changed
// on a rooted element.
this.byId = Object.create(null);
// This property holds a monotonically increasing value akin to
// a timestamp used to record the last modification time of nodes
// and their subtrees. See the lastModTime attribute and modify()
// method of the Node class. And see FilteredElementList for an example
// of the use of lastModTime
this.modclock = 0;
}
// Map from lowercase event category names (used as arguments to
// createEvent()) to the property name in the impl object of the
// event constructor.
var supportedEvents = {
event: 'Event',
customevent: 'CustomEvent',
uievent: 'UIEvent',
mouseevent: 'MouseEvent'
};
// Certain arguments to document.createEvent() must be treated specially
var replacementEvent = {
events: 'event',
htmlevents: 'event',
mouseevents: 'mouseevent',
mutationevents: 'mutationevent',
uievents: 'uievent'
};
var mirrorAttr = function(f, name, defaultValue) {
return {
get: function() {
var o = f.call(this);
if (o) { return o[name]; }
return defaultValue;
},
set: function(value) {
var o = f.call(this);
if (o) { o[name] = value; }
},
};
};
/** @spec https://dom.spec.whatwg.org/#validate-and-extract */
function validateAndExtract(namespace, qualifiedName) {
var prefix, localName, pos;
if (namespace==='') { namespace = null; }
// See https://github.com/whatwg/dom/issues/671
// and https://github.com/whatwg/dom/issues/319
if (!xml.isValidQName(qualifiedName)) {
utils.InvalidCharacterError();
}
prefix = null;
localName = qualifiedName;
pos = qualifiedName.indexOf(':');
if (pos >= 0) {
prefix = qualifiedName.substring(0, pos);
localName = qualifiedName.substring(pos+1);
}
if (prefix !== null && namespace === null) {
utils.NamespaceError();
}
if (prefix === 'xml' && namespace !== NAMESPACE.XML) {
utils.NamespaceError();
}
if ((prefix === 'xmlns' || qualifiedName === 'xmlns') &&
namespace !== NAMESPACE.XMLNS) {
utils.NamespaceError();
}
if (namespace === NAMESPACE.XMLNS && !(prefix==='xmlns' || qualifiedName==='xmlns')) {
utils.NamespaceError();
}
return { namespace: namespace, prefix: prefix, localName: localName };
}
Document.prototype = Object.create(ContainerNode.prototype, {
// This method allows dom.js to communicate with a renderer
// that displays the document in some way
// XXX: I should probably move this to the window object
_setMutationHandler: { value: function(handler) {
this.mutationHandler = handler;
}},
// This method allows dom.js to receive event notifications
// from the renderer.
// XXX: I should probably move this to the window object
_dispatchRendererEvent: { value: function(targetNid, type, details) {
var target = this._nodes[targetNid];
if (!target) return;
target._dispatchEvent(new Event(type, details), true);
}},
nodeName: { value: '#document'},
nodeValue: {
get: function() {
return null;
},
set: function() {}
},
// XXX: DOMCore may remove documentURI, so it is NYI for now
documentURI: { get: function() { return this._address; }, set: utils.nyi },
compatMode: { get: function() {
// The _quirks property is set by the HTML parser
return this._quirks ? 'BackCompat' : 'CSS1Compat';
}},
createTextNode: { value: function(data) {
return new Text(this, String(data));
}},
createComment: { value: function(data) {
return new Comment(this, data);
}},
createDocumentFragment: { value: function() {
return new DocumentFragment(this);
}},
createProcessingInstruction: { value: function(target, data) {
if (!xml.isValidName(target) || data.indexOf('?>') !== -1)
utils.InvalidCharacterError();
return new ProcessingInstruction(this, target, data);
}},
createAttribute: { value: function(localName) {
localName = String(localName);
if (!xml.isValidName(localName)) utils.InvalidCharacterError();
if (this.isHTML) {
localName = utils.toASCIILowerCase(localName);
}
return new Element._Attr(null, localName, null, null, '');
}},
createAttributeNS: { value: function(namespace, qualifiedName) {
// Convert parameter types according to WebIDL
namespace =
(namespace === null || namespace === undefined || namespace === '') ? null :
String(namespace);
qualifiedName = String(qualifiedName);
var ve = validateAndExtract(namespace, qualifiedName);
return new Element._Attr(null, ve.localName, ve.prefix, ve.namespace, '');
}},
createElement: { value: function(localName) {
localName = String(localName);
if (!xml.isValidName(localName)) utils.InvalidCharacterError();
// Per spec, namespace should be HTML namespace if "context object is
// an HTML document or context object's content type is
// "application/xhtml+xml", and null otherwise.
if (this.isHTML) {
if (/[A-Z]/.test(localName))
localName = utils.toASCIILowerCase(localName);
return html.createElement(this, localName, null);
} else if (this.contentType === 'application/xhtml+xml') {
return html.createElement(this, localName, null);
} else {
return new Element(this, localName, null, null);
}
}, writable: isApiWritable },
createElementNS: { value: function(namespace, qualifiedName) {
// Convert parameter types according to WebIDL
namespace =
(namespace === null || namespace === undefined || namespace === '') ? null :
String(namespace);
qualifiedName = String(qualifiedName);
var ve = validateAndExtract(namespace, qualifiedName);
return this._createElementNS(ve.localName, ve.namespace, ve.prefix);
}, writable: isApiWritable },
// This is used directly by HTML parser, which allows it to create
// elements with localNames containing ':' and non-default namespaces
_createElementNS: { value: function(localName, namespace, prefix) {
if (namespace === NAMESPACE.HTML) {
return html.createElement(this, localName, prefix);
}
else if (namespace === NAMESPACE.SVG) {
return svg.createElement(this, localName, prefix);
}
return new Element(this, localName, namespace, prefix);
}},
createEvent: { value: function createEvent(interfaceName) {
interfaceName = interfaceName.toLowerCase();
var name = replacementEvent[interfaceName] || interfaceName;
var constructor = events[supportedEvents[name]];
if (constructor) {
var e = new constructor();
e._initialized = false;
return e;
}
else {
utils.NotSupportedError();
}
}},
// See: http://www.w3.org/TR/dom/#dom-document-createtreewalker
createTreeWalker: {value: function (root, whatToShow, filter) {
if (!root) { throw new TypeError("root argument is required"); }
if (!(root instanceof Node)) { throw new TypeError("root not a node"); }
whatToShow = whatToShow === undefined ? NodeFilter.SHOW_ALL : (+whatToShow);
filter = filter === undefined ? null : filter;
return new TreeWalker(root, whatToShow, filter);
}},
// See: http://www.w3.org/TR/dom/#dom-document-createnodeiterator
createNodeIterator: {value: function (root, whatToShow, filter) {
if (!root) { throw new TypeError("root argument is required"); }
if (!(root instanceof Node)) { throw new TypeError("root not a node"); }
whatToShow = whatToShow === undefined ? NodeFilter.SHOW_ALL : (+whatToShow);
filter = filter === undefined ? null : filter;
return new NodeIterator(root, whatToShow, filter);
}},
_attachNodeIterator: { value: function(ni) {
// XXX ideally this should be a weak reference from Document to NodeIterator
if (!this._nodeIterators) { this._nodeIterators = []; }
this._nodeIterators.push(ni);
}},
_detachNodeIterator: { value: function(ni) {
// ni should always be in list of node iterators
var idx = this._nodeIterators.indexOf(ni);
this._nodeIterators.splice(idx, 1);
}},
_preremoveNodeIterators: { value: function(toBeRemoved) {
if (this._nodeIterators) {
this._nodeIterators.forEach(function(ni) { ni._preremove(toBeRemoved); });
}
}},
// Maintain the documentElement and
// doctype properties of the document. Each of the following
// methods chains to the Node implementation of the method
// to do the actual inserting, removal or replacement.
_updateDocTypeElement: { value: function _updateDocTypeElement() {
this.doctype = this.documentElement = null;
for (var kid = this.firstChild; kid !== null; kid = kid.nextSibling) {
if (kid.nodeType === Node.DOCUMENT_TYPE_NODE)
this.doctype = kid;
else if (kid.nodeType === Node.ELEMENT_NODE)
this.documentElement = kid;
}
}},
insertBefore: { value: function insertBefore(child, refChild) {
Node.prototype.insertBefore.call(this, child, refChild);
this._updateDocTypeElement();
return child;
}},
replaceChild: { value: function replaceChild(node, child) {
Node.prototype.replaceChild.call(this, node, child);
this._updateDocTypeElement();
return child;
}},
removeChild: { value: function removeChild(child) {
Node.prototype.removeChild.call(this, child);
this._updateDocTypeElement();
return child;
}},
getElementById: { value: function(id) {
var n = this.byId[id];
if (!n) return null;
if (n instanceof MultiId) { // there was more than one element with this id
return n.getFirst();
}
return n;
}},
_hasMultipleElementsWithId: { value: function(id) {
// Used internally by querySelectorAll optimization
return (this.byId[id] instanceof MultiId);
}},
// Just copy this method from the Element prototype
getElementsByName: { value: Element.prototype.getElementsByName },
getElementsByTagName: { value: Element.prototype.getElementsByTagName },
getElementsByTagNameNS: { value: Element.prototype.getElementsByTagNameNS },
getElementsByClassName: { value: Element.prototype.getElementsByClassName },
adoptNode: { value: function adoptNode(node) {
if (node.nodeType === Node.DOCUMENT_NODE) utils.NotSupportedError();
if (node.nodeType === Node.ATTRIBUTE_NODE) { return node; }
if (node.parentNode) node.parentNode.removeChild(node);
if (node.ownerDocument !== this)
recursivelySetOwner(node, this);
return node;
}},
importNode: { value: function importNode(node, deep) {
return this.adoptNode(node.cloneNode(deep));
}, writable: isApiWritable },
// The following attributes and methods are from the HTML spec
origin: { get: function origin() { return null; } },
characterSet: { get: function characterSet() { return "UTF-8"; } },
contentType: { get: function contentType() { return this._contentType; } },
URL: { get: function URL() { return this._address; } },
domain: { get: utils.nyi, set: utils.nyi },
referrer: { get: utils.nyi },
cookie: { get: utils.nyi, set: utils.nyi },
lastModified: { get: utils.nyi },
location: {
get: function() {
return this.defaultView ? this.defaultView.location : null; // gh #75
},
set: utils.nyi
},
_titleElement: {
get: function() {
// The title element of a document is the first title element in the
// document in tree order, if there is one, or null otherwise.
return this.getElementsByTagName('title').item(0) || null;
}
},
title: {
get: function() {
var elt = this._titleElement;
// The child text content of the title element, or '' if null.
var value = elt ? elt.textContent : '';
// Strip and collapse whitespace in value
return value.replace(/[ \t\n\r\f]+/g, ' ').replace(/(^ )|( $)/g, '');
},
set: function(value) {
var elt = this._titleElement;
var head = this.head;
if (!elt && !head) { return; /* according to spec */ }
if (!elt) {
elt = this.createElement('title');
head.appendChild(elt);
}
elt.textContent = value;
}
},
dir: mirrorAttr(function() {
var htmlElement = this.documentElement;
if (htmlElement && htmlElement.tagName === 'HTML') { return htmlElement; }
}, 'dir', ''),
fgColor: mirrorAttr(function() { return this.body; }, 'text', ''),
linkColor: mirrorAttr(function() { return this.body; }, 'link', ''),
vlinkColor: mirrorAttr(function() { return this.body; }, 'vLink', ''),
alinkColor: mirrorAttr(function() { return this.body; }, 'aLink', ''),
bgColor: mirrorAttr(function() { return this.body; }, 'bgColor', ''),
// Historical aliases of Document#characterSet
charset: { get: function() { return this.characterSet; } },
inputEncoding: { get: function() { return this.characterSet; } },
scrollingElement: {
get: function() {
return this._quirks ? this.body : this.documentElement;
}
},
// Return the first <body> child of the document element.
// XXX For now, setting this attribute is not implemented.
body: {
get: function() {
return namedHTMLChild(this.documentElement, 'body');
},
set: utils.nyi
},
// Return the first <head> child of the document element.
head: { get: function() {
return namedHTMLChild(this.documentElement, 'head');
}},
images: { get: utils.nyi },
embeds: { get: utils.nyi },
plugins: { get: utils.nyi },
links: { get: utils.nyi },
forms: { get: utils.nyi },
scripts: { get: utils.nyi },
applets: { get: function() { return []; } },
activeElement: { get: function() { return null; } },
innerHTML: {
get: function() { return this.serialize(); },
set: utils.nyi
},
outerHTML: {
get: function() { return this.serialize(); },
set: utils.nyi
},
write: { value: function(args) {
if (!this.isHTML) utils.InvalidStateError();
// XXX: still have to implement the ignore part
if (!this._parser /* && this._ignore_destructive_writes > 0 */ )
return;
if (!this._parser) {
// XXX call document.open, etc.
}
var s = arguments.join('');
// If the Document object's reload override flag is set, then
// append the string consisting of the concatenation of all the
// arguments to the method to the Document's reload override
// buffer.
// XXX: don't know what this is about. Still have to do it
// If there is no pending parsing-blocking script, have the
// tokenizer process the characters that were inserted, one at a
// time, processing resulting tokens as they are emitted, and
// stopping when the tokenizer reaches the insertion point or when
// the processing of the tokenizer is aborted by the tree
// construction stage (this can happen if a script end tag token is
// emitted by the tokenizer).
// XXX: still have to do the above. Sounds as if we don't
// always call parse() here. If we're blocked, then we just
// insert the text into the stream but don't parse it reentrantly...
// Invoke the parser reentrantly
this._parser.parse(s);
}},
writeln: { value: function writeln(args) {
this.write(Array.prototype.join.call(arguments, '') + '\n');
}},
open: { value: function() {
this.documentElement = null;
}},
close: { value: function() {
this.readyState = 'interactive';
this._dispatchEvent(new Event('readystatechange'), true);
this._dispatchEvent(new Event('DOMContentLoaded'), true);
this.readyState = 'complete';
this._dispatchEvent(new Event('readystatechange'), true);
if (this.defaultView) {
this.defaultView._dispatchEvent(new Event('load'), true);
}
}},
// Utility methods
clone: { value: function clone() {
var d = new Document(this.isHTML, this._address);
d._quirks = this._quirks;
d._contentType = this._contentType;
return d;
}},
// We need to adopt the nodes if we do a deep clone
cloneNode: { value: function cloneNode(deep) {
var clone = Node.prototype.cloneNode.call(this, false);
if (deep) {
for (var kid = this.firstChild; kid !== null; kid = kid.nextSibling) {
clone._appendChild(clone.importNode(kid, true));
}
}
clone._updateDocTypeElement();
return clone;
}},
isEqual: { value: function isEqual(n) {
// Any two documents are shallowly equal.
// Node.isEqualNode will also test the children
return true;
}},
// Implementation-specific function. Called when a text, comment,
// or pi value changes.
mutateValue: { value: function(node) {
if (this.mutationHandler) {
this.mutationHandler({
type: MUTATE.VALUE,
target: node,
data: node.data
});
}
}},
// Invoked when an attribute's value changes. Attr holds the new
// value. oldval is the old value. Attribute mutations can also
// involve changes to the prefix (and therefore the qualified name)
mutateAttr: { value: function(attr, oldval) {
// Manage id->element mapping for getElementsById()
// XXX: this special case id handling should not go here,
// but in the attribute declaration for the id attribute
/*
if (attr.localName === 'id' && attr.namespaceURI === null) {
if (oldval) delId(oldval, attr.ownerElement);
addId(attr.value, attr.ownerElement);
}
*/
if (this.mutationHandler) {
this.mutationHandler({
type: MUTATE.ATTR,
target: attr.ownerElement,
attr: attr
});
}
}},
// Used by removeAttribute and removeAttributeNS for attributes.
mutateRemoveAttr: { value: function(attr) {
/*
* This is now handled in Attributes.js
// Manage id to element mapping
if (attr.localName === 'id' && attr.namespaceURI === null) {
this.delId(attr.value, attr.ownerElement);
}
*/
if (this.mutationHandler) {
this.mutationHandler({
type: MUTATE.REMOVE_ATTR,
target: attr.ownerElement,
attr: attr
});
}
}},
// Called by Node.removeChild, etc. to remove a rooted element from
// the tree. Only needs to generate a single mutation event when a
// node is removed, but must recursively mark all descendants as not
// rooted.
mutateRemove: { value: function(node) {
// Send a single mutation event
if (this.mutationHandler) {
this.mutationHandler({
type: MUTATE.REMOVE,
target: node.parentNode,
node: node
});
}
// Mark this and all descendants as not rooted
recursivelyUproot(node);
}},
// Called when a new element becomes rooted. It must recursively
// generate mutation events for each of the children, and mark them all
// as rooted.
mutateInsert: { value: function(node) {
// Mark node and its descendants as rooted
recursivelyRoot(node);
// Send a single mutation event
if (this.mutationHandler) {
this.mutationHandler({
type: MUTATE.INSERT,
target: node.parentNode,
node: node
});
}
}},
// Called when a rooted element is moved within the document
mutateMove: { value: function(node) {
if (this.mutationHandler) {
this.mutationHandler({
type: MUTATE.MOVE,
target: node
});
}
}},
// Add a mapping from id to n for n.ownerDocument
addId: { value: function addId(id, n) {
var val = this.byId[id];
if (!val) {
this.byId[id] = n;
}
else {
// TODO: Add a way to opt-out console warnings
//console.warn('Duplicate element id ' + id);
if (!(val instanceof MultiId)) {
val = new MultiId(val);
this.byId[id] = val;
}
val.add(n);
}
}},
// Delete the mapping from id to n for n.ownerDocument
delId: { value: function delId(id, n) {
var val = this.byId[id];
utils.assert(val);
if (val instanceof MultiId) {
val.del(n);
if (val.length === 1) { // convert back to a single node
this.byId[id] = val.downgrade();
}
}
else {
this.byId[id] = undefined;
}
}},
_resolve: { value: function(href) {
//XXX: Cache the URL
return new URL(this._documentBaseURL).resolve(href);
}},
_documentBaseURL: { get: function() {
// XXX: This is not implemented correctly yet
var url = this._address;
if (url === 'about:blank') url = '/';
var base = this.querySelector('base[href]');
if (base) {
return new URL(url).resolve(base.getAttribute('href'));
}
return url;
// The document base URL of a Document object is the
// absolute URL obtained by running these substeps:
// Let fallback base url be the document's address.
// If fallback base url is about:blank, and the
// Document's browsing context has a creator browsing
// context, then let fallback base url be the document
// base URL of the creator Document instead.
// If the Document is an iframe srcdoc document, then
// let fallback base url be the document base URL of
// the Document's browsing context's browsing context
// container's Document instead.
// If there is no base element that has an href
// attribute, then the document base URL is fallback
// base url; abort these steps. Otherwise, let url be
// the value of the href attribute of the first such
// element.
// Resolve url relative to fallback base url (thus,
// the base href attribute isn't affected by xml:base
// attributes).
// The document base URL is the result of the previous
// step if it was successful; otherwise it is fallback
// base url.
}},
_templateDoc: { get: function() {
if (!this._templateDocCache) {
// "associated inert template document"
var newDoc = new Document(this.isHTML, this._address);
this._templateDocCache = newDoc._templateDocCache = newDoc;
}
return this._templateDocCache;
}},
querySelector: { value: function(selector) {
return select(selector, this)[0];
}},
querySelectorAll: { value: function(selector) {
var nodes = select(selector, this);
return nodes.item ? nodes : new NodeList(nodes);
}}
});
var eventHandlerTypes = [
'abort', 'canplay', 'canplaythrough', 'change', 'click', 'contextmenu',
'cuechange', 'dblclick', 'drag', 'dragend', 'dragenter', 'dragleave',
'dragover', 'dragstart', 'drop', 'durationchange', 'emptied', 'ended',
'input', 'invalid', 'keydown', 'keypress', 'keyup', 'loadeddata',
'loadedmetadata', 'loadstart', 'mousedown', 'mousemove', 'mouseout',
'mouseover', 'mouseup', 'mousewheel', 'pause', 'play', 'playing',
'progress', 'ratechange', 'readystatechange', 'reset', 'seeked',
'seeking', 'select', 'show', 'stalled', 'submit', 'suspend',
'timeupdate', 'volumechange', 'waiting',
'blur', 'error', 'focus', 'load', 'scroll'
];
// Add event handler idl attribute getters and setters to Document
eventHandlerTypes.forEach(function(type) {
// Define the event handler registration IDL attribute for this type
Object.defineProperty(Document.prototype, 'on' + type, {
get: function() {
return this._getEventHandler(type);
},
set: function(v) {
this._setEventHandler(type, v);
}
});
});
function namedHTMLChild(parent, name) {
if (parent && parent.isHTML) {
for (var kid = parent.firstChild; kid !== null; kid = kid.nextSibling) {
if (kid.nodeType === Node.ELEMENT_NODE &&
kid.localName === name &&
kid.namespaceURI === NAMESPACE.HTML) {
return kid;
}
}
}
return null;
}
function root(n) {
n._nid = n.ownerDocument._nextnid++;
n.ownerDocument._nodes[n._nid] = n;
// Manage id to element mapping
if (n.nodeType === Node.ELEMENT_NODE) {
var id = n.getAttribute('id');
if (id) n.ownerDocument.addId(id, n);
// Script elements need to know when they're inserted
// into the document
if (n._roothook) n._roothook();
}
}
function uproot(n) {
// Manage id to element mapping
if (n.nodeType === Node.ELEMENT_NODE) {
var id = n.getAttribute('id');
if (id) n.ownerDocument.delId(id, n);
}
n.ownerDocument._nodes[n._nid] = undefined;
n._nid = undefined;
}
function recursivelyRoot(node) {
root(node);
// XXX:
// accessing childNodes on a leaf node creates a new array the
// first time, so be careful to write this loop so that it
// doesn't do that. node is polymorphic, so maybe this is hard to
// optimize? Try switching on nodeType?
/*
if (node.hasChildNodes()) {
var kids = node.childNodes;
for(var i = 0, n = kids.length; i < n; i++)
recursivelyRoot(kids[i]);
}
*/
if (node.nodeType === Node.ELEMENT_NODE) {
for (var kid = node.firstChild; kid !== null; kid = kid.nextSibling)
recursivelyRoot(kid);
}
}
function recursivelyUproot(node) {
uproot(node);
for (var kid = node.firstChild; kid !== null; kid = kid.nextSibling)
recursivelyUproot(kid);
}
function recursivelySetOwner(node, owner) {
node.ownerDocument = owner;
node._lastModTime = undefined; // mod times are document-based
if (Object.prototype.hasOwnProperty.call(node, '_tagName')) {
node._tagName = undefined; // Element subclasses might need to change case
}
for (var kid = node.firstChild; kid !== null; kid = kid.nextSibling)
recursivelySetOwner(kid, owner);
}
// A class for storing multiple nodes with the same ID
function MultiId(node) {
this.nodes = Object.create(null);
this.nodes[node._nid] = node;
this.length = 1;
this.firstNode = undefined;
}
// Add a node to the list, with O(1) time
MultiId.prototype.add = function(node) {
if (!this.nodes[node._nid]) {
this.nodes[node._nid] = node;
this.length++;
this.firstNode = undefined;
}
};
// Remove a node from the list, with O(1) time
MultiId.prototype.del = function(node) {
if (this.nodes[node._nid]) {
delete this.nodes[node._nid];
this.length--;
this.firstNode = undefined;
}
};
// Get the first node from the list, in the document order
// Takes O(N) time in the size of the list, with a cache that is invalidated
// when the list is modified.
MultiId.prototype.getFirst = function() {
/* jshint bitwise: false */
if (!this.firstNode) {
var nid;
for (nid in this.nodes) {
if (this.firstNode === undefined ||
this.firstNode.compareDocumentPosition(this.nodes[nid]) & Node.DOCUMENT_POSITION_PRECEDING) {
this.firstNode = this.nodes[nid];
}
}
}
return this.firstNode;
};
// If there is only one node left, return it. Otherwise return "this".
MultiId.prototype.downgrade = function() {
if (this.length === 1) {
var nid;
for (nid in this.nodes) {
return this.nodes[nid];
}
}
return this;
};