1 files changed, 119 insertions, 0 deletions
diff --git a/toolkit/modules/sessionstore/XPathGenerator.jsm b/toolkit/modules/sessionstore/XPathGenerator.jsm
new file mode 100644
index 000000000..33f397cdf
--- /dev/null
+++ b/toolkit/modules/sessionstore/XPathGenerator.jsm
@@ -0,0 +1,119 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = ["XPathGenerator"];
+
+this.XPathGenerator = {
+  // these two hashes should be kept in sync
+  namespaceURIs:     {
+    "xhtml": "http://www.w3.org/1999/xhtml",
+    "xul": "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+  },
+  namespacePrefixes: {
+    "http://www.w3.org/1999/xhtml": "xhtml",
+    "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul": "xul"
+  },
+
+  /**
+   * Generates an approximate XPath query to an (X)HTML node
+   */
+  generate: function sss_xph_generate(aNode) {
+    // have we reached the document node already?
+    if (!aNode.parentNode)
+      return "";
+
+    // Access localName, namespaceURI just once per node since it's expensive.
+    let nNamespaceURI = aNode.namespaceURI;
+    let nLocalName = aNode.localName;
+
+    let prefix = this.namespacePrefixes[nNamespaceURI] || null;
+    let tag = (prefix ? prefix + ":" : "") + this.escapeName(nLocalName);
+
+    // stop once we've found a tag with an ID
+    if (aNode.id)
+      return "//" + tag + "[@id=" + this.quoteArgument(aNode.id) + "]";
+
+    // count the number of previous sibling nodes of the same tag
+    // (and possible also the same name)
+    let count = 0;
+    let nName = aNode.name || null;
+    for (let n = aNode; (n = n.previousSibling); )
+      if (n.localName == nLocalName && n.namespaceURI == nNamespaceURI &&
+          (!nName || n.name == nName))
+        count++;
+
+    // recurse until hitting either the document node or an ID'd node
+    return this.generate(aNode.parentNode) + "/" + tag +
+           (nName ? "[@name=" + this.quoteArgument(nName) + "]" : "") +
+           (count ? "[" + (count + 1) + "]" : "");
+  },
+
+  /**
+   * Resolves an XPath query generated by XPathGenerator.generate
+   */
+  resolve: function sss_xph_resolve(aDocument, aQuery) {
+    let xptype = Components.interfaces.nsIDOMXPathResult.FIRST_ORDERED_NODE_TYPE;
+    return aDocument.evaluate(aQuery, aDocument, this.resolveNS, xptype, null).singleNodeValue;
+  },
+
+  /**
+   * Namespace resolver for the above XPath resolver
+   */
+  resolveNS: function sss_xph_resolveNS(aPrefix) {
+    return XPathGenerator.namespaceURIs[aPrefix] || null;
+  },
+
+  /**
+   * @returns valid XPath for the given node (usually just the local name itself)
+   */
+  escapeName: function sss_xph_escapeName(aName) {
+    // we can't just use the node's local name, if it contains
+    // special characters (cf. bug 485482)
+    return /^\w+$/.test(aName) ? aName :
+           "*[local-name()=" + this.quoteArgument(aName) + "]";
+  },
+
+  /**
+   * @returns a properly quoted string to insert into an XPath query
+   */
+  quoteArgument: function sss_xph_quoteArgument(aArg) {
+    if (!/'/.test(aArg))
+      return "'" + aArg + "'";
+    if (!/"/.test(aArg))
+      return '"' + aArg + '"';
+    return "concat('" + aArg.replace(/'+/g, "',\"$&\",'") + "')";
+  },
+
+  /**
+   * @returns an XPath query to all savable form field nodes
+   */
+  get restorableFormNodes() {
+    // for a comprehensive list of all available <INPUT> types see
+    // https://dxr.mozilla.org/mozilla-central/search?q=kInputTypeTable&redirect=false
+    let ignoreInputs = new Map([
+      ["type", ["password", "hidden", "button", "image", "submit", "reset"]],
+      ["autocomplete", ["off"]]
+    ]);
+    // XXXzeniko work-around until lower-case has been implemented (bug 398389)
+    let toLowerCase = '"ABCDEFGHIJKLMNOPQRSTUVWXYZ", "abcdefghijklmnopqrstuvwxyz"';
+    let ignores = [];
+    for (let [attrName, attrValues] of ignoreInputs) {
+      for (let attrValue of attrValues)
+        ignores.push(`translate(@${attrName}, ${toLowerCase})='${attrValue}'`);
+    }
+    let ignore = `not(${ignores.join(" or ")})`;
+
+    let formNodesXPath = `//textarea[${ignore}]|//xhtml:textarea[${ignore}]|` +
+      `//select[${ignore}]|//xhtml:select[${ignore}]|` +
+      `//input[${ignore}]|//xhtml:input[${ignore}]`;
+
+    // Special case for about:config's search field.
+    formNodesXPath += '|/xul:window[@id="config"]//xul:textbox[@id="textbox"]';
+
+    delete this.restorableFormNodes;
+    return (this.restorableFormNodes = formNodesXPath);
+  }
+};