michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: const Ci = Components.interfaces;
michael@0: const Cu = Components.utils;
michael@0: Cu.import("resource://gre/modules/Services.jsm");
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["DOMHelpers"];
michael@0: 
michael@0: /**
michael@0:  * DOMHelpers
michael@0:  * Makes DOM traversal easier. Goes through iframes.
michael@0:  *
michael@0:  * @constructor
michael@0:  * @param nsIDOMWindow aWindow
michael@0:  *        The content window, owning the document to traverse.
michael@0:  */
michael@0: this.DOMHelpers = function DOMHelpers(aWindow) {
michael@0:   if (!aWindow) {
michael@0:     throw new Error("window can't be null or undefined");
michael@0:   }
michael@0:   this.window = aWindow;
michael@0: };
michael@0: 
michael@0: DOMHelpers.prototype = {
michael@0:   getParentObject: function Helpers_getParentObject(node)
michael@0:   {
michael@0:     let parentNode = node ? node.parentNode : null;
michael@0: 
michael@0:     if (!parentNode) {
michael@0:       // Documents have no parentNode; Attr, Document, DocumentFragment, Entity,
michael@0:       // and Notation. top level windows have no parentNode
michael@0:       if (node && node == this.window.Node.DOCUMENT_NODE) {
michael@0:         // document type
michael@0:         if (node.defaultView) {
michael@0:           let embeddingFrame = node.defaultView.frameElement;
michael@0:           if (embeddingFrame)
michael@0:             return embeddingFrame.parentNode;
michael@0:         }
michael@0:       }
michael@0:       // a Document object without a parentNode or window
michael@0:       return null;  // top level has no parent
michael@0:     }
michael@0: 
michael@0:     if (parentNode.nodeType == this.window.Node.DOCUMENT_NODE) {
michael@0:       if (parentNode.defaultView) {
michael@0:         return parentNode.defaultView.frameElement;
michael@0:       }
michael@0:       // parent is document element, but no window at defaultView.
michael@0:       return null;
michael@0:     }
michael@0: 
michael@0:     if (!parentNode.localName)
michael@0:       return null;
michael@0: 
michael@0:     return parentNode;
michael@0:   },
michael@0: 
michael@0:   getChildObject: function Helpers_getChildObject(node, index, previousSibling,
michael@0:                                                 showTextNodesWithWhitespace)
michael@0:   {
michael@0:     if (!node)
michael@0:       return null;
michael@0: 
michael@0:     if (node.contentDocument) {
michael@0:       // then the node is a frame
michael@0:       if (index == 0) {
michael@0:         return node.contentDocument.documentElement;  // the node's HTMLElement
michael@0:       }
michael@0:       return null;
michael@0:     }
michael@0: 
michael@0:     if (node.getSVGDocument) {
michael@0:       let svgDocument = node.getSVGDocument();
michael@0:       if (svgDocument) {
michael@0:         // then the node is a frame
michael@0:         if (index == 0) {
michael@0:           return svgDocument.documentElement;  // the node's SVGElement
michael@0:         }
michael@0:         return null;
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     let child = null;
michael@0:     if (previousSibling)  // then we are walking
michael@0:       child = this.getNextSibling(previousSibling);
michael@0:     else
michael@0:       child = this.getFirstChild(node);
michael@0: 
michael@0:     if (showTextNodesWithWhitespace)
michael@0:       return child;
michael@0: 
michael@0:     for (; child; child = this.getNextSibling(child)) {
michael@0:       if (!this.isWhitespaceText(child))
michael@0:         return child;
michael@0:     }
michael@0: 
michael@0:     return null;  // we have no children worth showing.
michael@0:   },
michael@0: 
michael@0:   getFirstChild: function Helpers_getFirstChild(node)
michael@0:   {
michael@0:     let SHOW_ALL = Components.interfaces.nsIDOMNodeFilter.SHOW_ALL;
michael@0:     this.treeWalker = node.ownerDocument.createTreeWalker(node,
michael@0:       SHOW_ALL, null);
michael@0:     return this.treeWalker.firstChild();
michael@0:   },
michael@0: 
michael@0:   getNextSibling: function Helpers_getNextSibling(node)
michael@0:   {
michael@0:     let next = this.treeWalker.nextSibling();
michael@0: 
michael@0:     if (!next)
michael@0:       delete this.treeWalker;
michael@0: 
michael@0:     return next;
michael@0:   },
michael@0: 
michael@0:   isWhitespaceText: function Helpers_isWhitespaceText(node)
michael@0:   {
michael@0:     return node.nodeType == this.window.Node.TEXT_NODE &&
michael@0:                             !/[^\s]/.exec(node.nodeValue);
michael@0:   },
michael@0: 
michael@0:   destroy: function Helpers_destroy()
michael@0:   {
michael@0:     delete this.window;
michael@0:     delete this.treeWalker;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * A simple way to be notified (once) when a window becomes
michael@0:    * interactive (DOMContentLoaded).
michael@0:    *
michael@0:    * It is based on the chromeEventHandler. This is useful when
michael@0:    * chrome iframes are loaded in content docshells (in Firefox
michael@0:    * tabs for example).
michael@0:    */
michael@0:   onceDOMReady: function Helpers_onLocationChange(callback) {
michael@0:     let window = this.window;
michael@0:     let docShell = window.QueryInterface(Ci.nsIInterfaceRequestor)
michael@0:                          .getInterface(Ci.nsIWebNavigation)
michael@0:                          .QueryInterface(Ci.nsIDocShell);
michael@0:     let onReady = function(event) {
michael@0:       if (event.target == window.document) {
michael@0:         docShell.chromeEventHandler.removeEventListener("DOMContentLoaded", onReady, false);
michael@0:         // If in `callback` the URL of the window is changed and a listener to DOMContentLoaded
michael@0:         // is attached, the event we just received will be also be caught by the new listener.
michael@0:         // We want to avoid that so we execute the callback in the next queue.
michael@0:         Services.tm.mainThread.dispatch(callback, 0);
michael@0:       }
michael@0:     }
michael@0:     docShell.chromeEventHandler.addEventListener("DOMContentLoaded", onReady, false);
michael@0:   }
michael@0: };