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 file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["XPathGenerator"];
michael@0: 
michael@0: this.XPathGenerator = {
michael@0:   // these two hashes should be kept in sync
michael@0:   namespaceURIs:     {
michael@0:     "xhtml": "http://www.w3.org/1999/xhtml",
michael@0:     "xul": "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
michael@0:   },
michael@0:   namespacePrefixes: {
michael@0:     "http://www.w3.org/1999/xhtml": "xhtml",
michael@0:     "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul": "xul"
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Generates an approximate XPath query to an (X)HTML node
michael@0:    */
michael@0:   generate: function sss_xph_generate(aNode) {
michael@0:     // have we reached the document node already?
michael@0:     if (!aNode.parentNode)
michael@0:       return "";
michael@0: 
michael@0:     // Access localName, namespaceURI just once per node since it's expensive.
michael@0:     let nNamespaceURI = aNode.namespaceURI;
michael@0:     let nLocalName = aNode.localName;
michael@0: 
michael@0:     let prefix = this.namespacePrefixes[nNamespaceURI] || null;
michael@0:     let tag = (prefix ? prefix + ":" : "") + this.escapeName(nLocalName);
michael@0: 
michael@0:     // stop once we've found a tag with an ID
michael@0:     if (aNode.id)
michael@0:       return "//" + tag + "[@id=" + this.quoteArgument(aNode.id) + "]";
michael@0: 
michael@0:     // count the number of previous sibling nodes of the same tag
michael@0:     // (and possible also the same name)
michael@0:     let count = 0;
michael@0:     let nName = aNode.name || null;
michael@0:     for (let n = aNode; (n = n.previousSibling); )
michael@0:       if (n.localName == nLocalName && n.namespaceURI == nNamespaceURI &&
michael@0:           (!nName || n.name == nName))
michael@0:         count++;
michael@0: 
michael@0:     // recurse until hitting either the document node or an ID'd node
michael@0:     return this.generate(aNode.parentNode) + "/" + tag +
michael@0:            (nName ? "[@name=" + this.quoteArgument(nName) + "]" : "") +
michael@0:            (count ? "[" + (count + 1) + "]" : "");
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Resolves an XPath query generated by XPathGenerator.generate
michael@0:    */
michael@0:   resolve: function sss_xph_resolve(aDocument, aQuery) {
michael@0:     let xptype = Components.interfaces.nsIDOMXPathResult.FIRST_ORDERED_NODE_TYPE;
michael@0:     return aDocument.evaluate(aQuery, aDocument, this.resolveNS, xptype, null).singleNodeValue;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Namespace resolver for the above XPath resolver
michael@0:    */
michael@0:   resolveNS: function sss_xph_resolveNS(aPrefix) {
michael@0:     return XPathGenerator.namespaceURIs[aPrefix] || null;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * @returns valid XPath for the given node (usually just the local name itself)
michael@0:    */
michael@0:   escapeName: function sss_xph_escapeName(aName) {
michael@0:     // we can't just use the node's local name, if it contains
michael@0:     // special characters (cf. bug 485482)
michael@0:     return /^\w+$/.test(aName) ? aName :
michael@0:            "*[local-name()=" + this.quoteArgument(aName) + "]";
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * @returns a properly quoted string to insert into an XPath query
michael@0:    */
michael@0:   quoteArgument: function sss_xph_quoteArgument(aArg) {
michael@0:     return !/'/.test(aArg) ? "'" + aArg + "'" :
michael@0:            !/"/.test(aArg) ? '"' + aArg + '"' :
michael@0:            "concat('" + aArg.replace(/'+/g, "',\"$&\",'") + "')";
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * @returns an XPath query to all savable form field nodes
michael@0:    */
michael@0:   get restorableFormNodes() {
michael@0:     // for a comprehensive list of all available <INPUT> types see
michael@0:     // http://mxr.mozilla.org/mozilla-central/search?string=kInputTypeTable
michael@0:     let ignoreTypes = ["password", "hidden", "button", "image", "submit", "reset"];
michael@0:     // XXXzeniko work-around until lower-case has been implemented (bug 398389)
michael@0:     let toLowerCase = '"ABCDEFGHIJKLMNOPQRSTUVWXYZ", "abcdefghijklmnopqrstuvwxyz"';
michael@0:     let ignore = "not(translate(@type, " + toLowerCase + ")='" +
michael@0:       ignoreTypes.join("' or translate(@type, " + toLowerCase + ")='") + "')";
michael@0:     let formNodesXPath = "//textarea|//select|//xhtml:textarea|//xhtml:select|" +
michael@0:       "//input[" + ignore + "]|//xhtml:input[" + ignore + "]";
michael@0: 
michael@0:     // Special case for about:config's search field.
michael@0:     formNodesXPath += '|/xul:window[@id="config"]//xul:textbox[@id="textbox"]';
michael@0: 
michael@0:     delete this.restorableFormNodes;
michael@0:     return (this.restorableFormNodes = formNodesXPath);
michael@0:   }
michael@0: };