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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
cr.define('print_preview', function() {
'use strict';
/**
* Class that represents a UI component.
* @constructor
* @extends {cr.EventTarget}
*/
function Component() {
cr.EventTarget.call(this);
/**
* Component's HTML element.
* @type {Element}
* @private
*/
this.element_ = null;
this.isInDocument_ = false;
/**
* Component's event tracker.
* @type {EventTracker}
* @private
*/
this.tracker_ = new EventTracker();
/**
* Child components of the component.
* @type {Array.<print_preview.Component>}
* @private
*/
this.children_ = [];
};
Component.prototype = {
__proto__: cr.EventTarget.prototype,
/** Gets the component's element. */
getElement: function() {
return this.element_;
},
/** @return {EventTracker} Component's event tracker. */
get tracker() {
return this.tracker_;
},
/**
* @return {boolean} Whether the element of the component is already in the
* HTML document.
*/
get isInDocument() {
return this.isInDocument_;
},
/**
* Creates the root element of the component. Sub-classes should override
* this method.
*/
createDom: function() {
this.element_ = cr.doc.createElement('div');
},
/**
* Called when the component's element is known to be in the document.
* Anything using document.getElementById etc. should be done at this stage.
* Sub-classes should extend this method and attach listeners.
*/
enterDocument: function() {
this.isInDocument_ = true;
this.children_.forEach(function(child) {
if (!child.isInDocument && child.getElement()) {
child.enterDocument();
}
});
},
/** Removes all event listeners. */
exitDocument: function() {
this.children_.forEach(function(child) {
if (child.isInDocument) {
child.exitDocument();
}
});
this.tracker_.removeAll();
this.isInDocument_ = false;
},
/**
* Renders this UI component and appends the element to the given parent
* element.
* @param {!Element} parentElement Element to render the component's
* element into.
*/
render: function(parentElement) {
assert(!this.isInDocument, 'Component is already in the document');
if (!this.element_) {
this.createDom();
}
parentElement.appendChild(this.element_);
this.enterDocument();
},
/**
* Decorates an existing DOM element. Sub-classes should override the
* override the decorateInternal method.
* @param {Element} element Element to decorate.
*/
decorate: function(element) {
assert(!this.isInDocument, 'Component is already in the document');
this.setElementInternal(element);
this.decorateInternal();
this.enterDocument();
},
/**
* @param {print_preview.Component} child Component to add as a child of
* this component.
*/
addChild: function(child) {
this.children_.push(child);
},
/**
* @param {!print_preview.Component} child Component to remove from this
* component's children.
*/
removeChild: function(child) {
var childIdx = this.children_.indexOf(child);
if (childIdx != -1) {
this.children_.splice(childIdx, 1);
}
if (child.isInDocument) {
child.exitDocument();
if (child.getElement()) {
child.getElement().parentNode.removeChild(child.getElement());
}
}
},
/** Removes all of the component's children. */
removeChildren: function() {
while (this.children_.length > 0) {
this.removeChild(this.children_[0]);
}
},
/**
* @param {string} query Selector query to select an element starting from
* the component's root element using a depth first search for the first
* element that matches the query.
* @return {HTMLElement} Element selected by the given query.
*/
getChildElement: function(query) {
return this.element_.querySelector(query);
},
/**
* Sets the component's element.
* @param {Element} element HTML element to set as the component's element.
* @protected
*/
setElementInternal: function(element) {
this.element_ = element;
},
/**
* Decorates the given element for use as the element of the component.
* @protected
*/
decorateInternal: function() { /*abstract*/ },
/**
* Clones a template HTML DOM tree.
* @param {string} templateId Template element ID.
* @param {boolean=} opt_keepHidden Whether to leave the cloned template
* hidden after cloning.
* @return {Element} Cloned element with its 'id' attribute stripped.
* @protected
*/
cloneTemplateInternal: function(templateId, opt_keepHidden) {
var templateEl = $(templateId);
assert(templateEl != null,
'Could not find element with ID: ' + templateId);
var el = templateEl.cloneNode(true);
el.id = '';
if (!opt_keepHidden) {
setIsVisible(el, true);
}
return el;
}
};
return {
Component: Component
};
});
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