mz-xpath.js

/*
	html-xpath, an implementation of DOM Level 3 XPath for Internet Explorer 5+
	Copyright (C) 2004 Dimitri Glazkov

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.

	This library is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public
	License along with this library; if not, write to the Free Software

*/

//var isIe = /MSIE [56789]/.test(navigator.userAgent) && (navigator.platform == "Win32");

// Mozilla has support by default, we don't have an implementation for the rest
//if (isIe)
if (document.evaluate === undefined)
{
	// release number
	document.DomL3XPathRelease = "0.0.3.0";
	
	// XPathException
	// An Error object will be thrown, this is just a handler to instantiate that object
	var XPathException = new _XPathExceptionHandler();
	function _XPathExceptionHandler()
	{
		this.INVALID_EXPRESSION_ERR = 51;
		this.TYPE_ERR = 52;
		this.NOT_IMPLEMENTED_ERR = -1;
		this.RUNTIME_ERR = -2;
		
		this.ThrowNotImplemented = function(message)
		{
			ThrowError(this.NOT_IMPLEMENTED_ERR, "This functionality is not implemented.", message);
		}
		
		this.ThrowInvalidExpression = function(message)
		{
			ThrowError(this.INVALID_EXPRESSION_ERR, "Invalid expression", message);
		}
		
		this.ThrowType = function(message)
		{
			ThrowError(this.TYPE_ERR, "Type error", message);
		}
		
		this.Throw = function(message)
		{
			ThrowError(this.RUNTIME_ERR, "Run-time error", message);
		}
		
		function ThrowError(code, description, message)
		{
			var error = new Error(code, "DOM-L3-XPath " + document.DomL3XPathRelease + ": " + description + (message ? ", \"" + message  + "\"": ""));
			error.code = code;
			error.name = "XPathException";
			throw error;
		}
	}
	
	// DOMException
	// An Error object will be thrown, this is just a handler to instantiate that object
	var DOMException = new _DOMExceptionHandler();
	function _DOMExceptionHandler()
	{
		this.ThrowInvalidState = function(message)
		{
			ThrowError(13, "The state of the object is no longer valid", message);
		}

		function ThrowError(code, description, message)
		{
			var error = new Error(code, "DOM : " + description + (message ? ", \"" + message  + "\"": ""));
			error.code = code;
			error.name = "DOMException";
			throw error;
		}
	}

	// XPathEvaluator 
	// implemented as document object methods
	
	// XPathExpression createExpression(String expression, XPathNSResolver resolver)
	document.createExpression = function
		(
		expression,		// String
		resolver		// XPathNSResolver
		)
	{
		// returns XPathExpression object
		return new XPathExpression(expression, resolver);
	}

	// XPathNSResolver createNSResolver(nodeResolver)
	document.createNSResolver = function
		(
		nodeResolver	// Node
		)
	{
		// returns XPathNSResolver
		return new XPathNSResolver(nodeResolver);
	}

	// XPathResult evaluate(String expresison, Node contextNode, XPathNSResolver resolver, Number type, XPathResult result)
	document.evaluate = function
		(
		expression,		// String
		contextNode,	// Node
		resolver,		// XPathNSResolver
		type,			// Number
		result			// XPathResult
		)
		// can raise XPathException, DOMException
	{
		// return XPathResult
		return document.createExpression(expression, resolver).evaluate(contextNode, type, result);
	}

	// XPathExpression
	function XPathExpression
	(
		expression, // String
		resolver // XPathNSResolver
	)
	{
		this.expressionString = expression;
		this.resolver = resolver;

		// XPathResult evaluate(Node contextNode, Number type, XPathResult result)
		this.evaluate = function
		(
			contextNode, // Node
			type, // Number
			result // XPathResult		
		)
			// raises XPathException, DOMException
		{
			// return XPathResult
			return (result && result.constructor == XPathResult ? result.initialize(this, contextNode, resolver, type) : new XPathResult(this, contextNode, resolver, type));
		}
		
		this.toString = function()
		{
			return "[XPathExpression]";
		}
	}

	// XPathNSResolver
	function XPathNSResolver(node)
	{
		this.node = node;
	
		// String lookupNamespaceURI(String prefix)
		this.lookupNamespaceURI = function
			(
			prefix			// String
			)
		{
			XPathException.ThrowNotImplemented();
			// return String
			return null;
		}

		this.toString = function()
		{
			return "[XPathNSResolver]";
		}
	}

	// XPathResult
	XPathResult.ANY_TYPE = 0;
	XPathResult.NUMBER_TYPE = 1;
	XPathResult.STRING_TYPE = 2;
	XPathResult.BOOLEAN_TYPE = 3;
	XPathResult.UNORDERED_NODE_ITERATOR_TYPE = 4;
	XPathResult.ORDERED_NODE_ITERATOR_TYPE = 5;
	XPathResult.UNORDERED_SNAPSHOT_TYPE = 6;
	XPathResult.ORDERED_SNAPSHOT_TYPE = 7;
	XPathResult.ANY_UNORDERED_NODE_TYPE = 8;
	XPathResult.FIRST_ORDERED_NODE_TYPE = 9;
	
	function XPathResult
			(
			expression,		// XPathExpression
			contextNode,	// Node
			resolver,		// XPathNSResolver
			type			// Number
			)
	{
		this.initialize = function(expression, contextNode, resolver, type)
		{
			this._domResult = null;
			this._expression = expression;
			this._contextNode = contextNode;
			this._resolver = resolver;
			if (type)
			{
				this.resultType = type;
				this._isIterator = (type == XPathResult.UNORDERED_NODE_ITERATOR_TYPE || 
					type == XPathResult.ORDERED_NODE_ITERATOR_TYPE || 
					type == XPathResult.ANY_TYPE);
				this._isSnapshot = (type == XPathResult.UNORDERED_SNAPSHOT_TYPE || type == XPathResult.ORDERED_SNAPSHOT_TYPE);
				this._isNodeSet = type > XPathResult.BOOLEAN_TYPE;
			}
			else
			{
				this.resultType = XPathResult.ANY_TYPE;
				this._isIterator = true;
				this._isSnapshot = false;
				this._isNodeSet = true;
			}
			return this;
		}
		
		this.initialize(expression, contextNode, resolver, type);
		
		this.getInvalidIteratorState = function()
		{
			return documentChangeDetected() || !this._isIterator;			
		}
		
		this.getSnapshotLength = function()
			// raises XPathException
		{
			if (!this._isSnapshot)
			{
				XPathException.ThrowType("Snapshot is not an expected result type");
			}
			activateResult(this);
			// return Number
			return this._domResult.length;
		}
		
		// Node iterateNext()
		this.iterateNext = function()
			// raises XPathException, DOMException
		{
			if (!this._isIterator)
			{
				XPathException.ThrowType("Iterator is not an expected result type");
			}
			activateResult(this);
			if (documentChangeDetected())
			{
				DOMException.ThrowInvalidState("iterateNext");
			}
			// return Node
			return getNextNode(this);
		}
		
		// Node snapshotItem(Number index)
		this.snapshotItem = function(index)
			// raises XPathException
		{
			if (!this._isSnapshot)
			{
				XPathException.ThrowType("Snapshot is not an expected result type");
			}
			// return Node
			return getItemNode(this, index); 
		}
		
		this.toString = function()
		{
			return "[XPathResult]";
		}
		
		// returns string value of the result, if result type is STRING_TYPE
		// otherwise throws an XPathException
		this.getStringValue = function()
		{
			if (this.resultType != XPathResult.STRING_TYPE)
			{
				XPathException.ThrowType("The expression can not be converted to return String");
			}
			return getNodeText(this);
		}
		
		// returns number value of the result, if the result is NUMBER_TYPE
		// otherwise throws an XPathException
		this.getNumberValue = function()
		{
			if (this.resultType != XPathResult.NUMBER_TYPE)
			{
				XPathException.ThrowType("The expression can not be converted to return Number");
			}
			var number = parseInt(getNodeText(this));
			if (isNaN(number))
			{
				XPathException.ThrowType("The result can not be converted to Number");
			}
			return number;
		}
		
		// returns boolean value of the result, if the result is BOOLEAN_TYPE
		// otherwise throws an XPathException
		this.getBooleanValue = function()
		{
			if (this.resultType != XPathResult.BOOLEAN_TYPE)
			{
				XPathException.ThrowType("The expression can not be converted to return Boolean");
			}
			
			var	
				text = getNodeText(this);
				bool = (text ? text.toLowerCase() : null);
			if (bool == "false" || bool == "true")
			{
				return bool;
			}
			XPathException.ThrowType("The result can not be converted to Boolean");
		}
		
		// returns single node, if the result is ANY_UNORDERED_NODE_TYPE or FIRST_ORDERED_NODE_TYPE
		// otherwise throws an XPathException
		this.getSingleNodeValue = function()
		{
			if (this.resultType != XPathResult.ANY_UNORDERED_NODE_TYPE && 
				this.resultType != XPathResult.FIRST_ORDERED_NODE_TYPE)
			{
				XPathException.ThrowType("The expression can not be converted to return single Node value");
			}
			return getSingleNode(this);
		}
		
		function documentChangeDetected()
		{
			return document._XPathMsxmlDocumentHelper.documentChangeDetected();
		}
		
		function getNodeText(result)
		{
			activateResult(result);
			return result._textResult;
//			return ((node = getSingleNode(result)) ? (node.nodeType == 1 ? node.innerText : node.nodeValue) : null);
		}
		
		function findNode(result, current)
		{
			switch(current.nodeType)
			{
				case 1: // NODE_ELEMENT
					var id = current.attributes.getNamedItem("id");
					if (id)
					{
						return document.getElementById(id.value);
					}
					XPathException.Throw("unable to locate element in XML tree");
				case 2: // NODE_ATTRIBUTE
					var id = current.selectSingleNode("..").attributes.getNamedItem("id");
					if (id)
					{
						var node = document.getElementById(id.text);
						if (node)
						{
							return node.attributes.getNamedItem(current.nodeName);
						}
					}
					XPathException.Throw("unable to locate attribute in XML tree");
				case 3: // NODE_TEXT
					var id = current.selectSingleNode("..").attributes.getNamedItem("id");
					if (id)
					{
						var node = document.getElementById(id.value);
						if (node)
						{
							for(child in node.childNodes)
							{
								if (child.nodeType == 3 && child.nodeValue == current.nodeValue)
								{
									return child;
								}
							}
						}
					}
					XPathException.Throw("unable to locate text in XML tree");
			}
			XPathException.Throw("unknown node type");
		}
		
		function activateResult(result)
		{
			if (!result._domResult)
			{
				try
				{
					var expression = result._expression.expressionString;
					
					// adjust expression if contextNode is not a document
					if (result._contextNode != document && expression.indexOf("//") != 0)
					{
						
						expression = "//*[@id = '" + result._contextNode.id + "']" + 
							(expression.indexOf("/") == 0 ? "" : "/") + expression;
					}
					
					if (result._isNodeSet)
					{
						result._domResult = document._XPathMsxmlDocumentHelper.getDom().selectNodes(expression);
					}
					else
					{
						result._domResult = true;
						result._textResult = document._XPathMsxmlDocumentHelper.getTextResult(expression);
					}
					
				}
				catch(error)
				{
					alert(error.description);
					XPathException.ThrowInvalidExpression(error.description);
				}
			}
		}

		function getSingleNode(result)
		{
			var node = getItemNode(result, 0);
			result._domResult = null;
			return node;
		}
		
		function getItemNode(result, index)
		{
			activateResult(result);
			var current = result._domResult.item(index);
			return (current ? findNode(result, current) : null);
		}
		
		function getNextNode(result)
		{
			var current = result._domResult.nextNode;
			if (current)
			{
				return findNode(result, current);
			}
			result._domResult = null;
			return null;
		}
	}
	
	document.reloadDom = function()
	{
		document._XPathMsxmlDocumentHelper.reset();
	}

	document._XPathMsxmlDocumentHelper = new _XPathMsxmlDocumentHelper();
	function _XPathMsxmlDocumentHelper()
	{
		this.getDom = function()
		{
			activateDom(this);
			return this.dom;
		}
		
		this.getXml = function()
		{
			activateDom(this);
			return this.dom.xml;
		}
		
		this.getTextResult = function(expression)
		{
			expression = expression.replace(/</g, "&lt;").replace(/>/g, "&gt;").replace(/"/g, "\"");
			var xslText = "<xsl:stylesheet version=\"1.0\" xmlns:xsl=\"http://www.w3.org/1999/XSL/Transform\">" +
				"<xsl:output method=\"text\"/><xsl:template match=\"*\"><xsl:value-of select=\"" + expression + "\"/>" +
				"</xsl:template></xsl:stylesheet>";
			var xsl = new ActiveXObject("Msxml2.DOMDocument");
			xsl.loadXML(xslText);
			try
			{
				var result = this.getDom().transformNode(xsl);
			}
			catch(error)
			{
				alert("Error: " + error.description);
			}
			return result;
		}
		
		this.reset = function()
		{
			this.dom = null;
		}
		
		function onPropertyChangeEventHandler()
		{
			document._propertyChangeDetected = true;
		}
		
		this.documentChangeDetected = function()
		{
			return (document.ignoreDocumentChanges ? false : this._currentElementCount != document.all.length || document._propertyChangeDetected);
		}
		
		function activateDom(helper)
		{
			if (!helper.dom)
			{
				var dom = new ActiveXObject("Msxml2.DOMDocument");
				dom.async = false;
				dom.resolveExternals = false;
				loadDocument(dom, helper);
				helper.dom = dom;
				helper._currentElementCount = document.all.length;
				document._propertyChangeDetected = false;
			}
			else
			{
				if (helper.documentChangeDetected())
				{
					var dom = helper.dom;
					dom.load("");
					loadDocument(dom, helper);
					helper._currentElementCount = document.all.length;
					document._propertyChangeDetected = false;
				}
			}
		}
		
		function loadDocument(dom, helper)
		{
			return loadNode(dom, dom, document.body, helper);		
		}
		
		function loadNode(dom, domParentNode, node, helper)
		{
			if (node.nodeType == 3)
			{			
				domParentNode.appendChild(dom.createTextNode(node.nodeValue));
			}
			else
			{
				var domNode = dom.createElement(node.nodeName.toLowerCase());
				if (!node.id)
				{
					node.id = node.uniqueID;
				}
				domParentNode.appendChild(domNode);
				loadAttributes(dom, domNode, node);
				var length = node.childNodes.length;
				for(var i = 0; i < length; i ++ )
				{
					loadNode(dom, domNode, node.childNodes[i], helper);
				}
				node.attachEvent("onpropertychange", onPropertyChangeEventHandler);
			}
		}

		function loadAttributes(dom, domParentNode, node)
		{
			for (var i = 0; i < node.attributes.length; i ++ )
			{
				var attribute = node.attributes[i];
				var attributeValue = attribute.nodeValue;
				if (attributeValue && attribute.specified)
				{
					var domAttribute = dom.createAttribute(attribute.nodeName);
					domAttribute.value = attributeValue;
					domParentNode.setAttributeNode(domAttribute);				
				}
			}
		}
	
	}
}
/*
else
{
	document.reloadDom = function() {}
	XPathResult.prototype.getStringValue = function()
	{
		return this.stringValue;
	}
	
	XPathResult.prototype.getNumberValue = function()
	{
		return this.numberValue;
	}
	
	XPathResult.prototype.getBooleanValue = function()
	{
		return this.booleanValue;
	}
	
	XPathResult.prototype.getSingleNodeValue = function()
	{
		return this.singleNodeValue;	
	}
	
	XPathResult.prototype.getInvalidIteratorState = function()
	{
		return this.invalidIteratorState;
	}
	
	XPathResult.prototype.getSnapshotLength = function()
	{
		return this.snapshotLength;
	}
	
	XPathResult.prototype.getResultType = function()
	{
		return this.resultType;
	}
}
*/
window.console.log('mz-xpath loaded');