1 files changed, 110 insertions, 0 deletions
diff --git a/comm/calendar/providers/caldav/modules/CalDavUtils.jsm b/comm/calendar/providers/caldav/modules/CalDavUtils.jsm
new file mode 100644
index 0000000000..63b50b7fb3
--- /dev/null
+++ b/comm/calendar/providers/caldav/modules/CalDavUtils.jsm
@@ -0,0 +1,110 @@
+/* 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/. */
+
+var { cal } = ChromeUtils.import("resource:///modules/calendar/calUtils.jsm");
+
+/**
+ * Various utility functions for the caldav provider
+ */
+
+/* exported CalDavXmlns, CalDavTagsToXmlns, CalDavNsUnresolver, CalDavNsResolver, CalDavXPath,
+ *          CalDavXPathFirst */
+const EXPORTED_SYMBOLS = [
+  "CalDavXmlns",
+  "CalDavTagsToXmlns",
+  "CalDavNsUnresolver",
+  "CalDavNsResolver",
+  "CalDavXPath",
+  "CalDavXPathFirst",
+];
+
+/**
+ * Creates an xmlns string with the requested namespace prefixes
+ *
+ * @param {...string} aRequested - The requested namespace prefixes
+ * @returns {string} An xmlns string that can be inserted into xml documents
+ */
+function CalDavXmlns(...aRequested) {
+  let namespaces = [];
+  for (let namespace of aRequested) {
+    let nsUri = CalDavNsResolver(namespace);
+    if (namespace) {
+      namespaces.push(`xmlns:${namespace}='${nsUri}'`);
+    }
+  }
+
+  return namespaces.join(" ");
+}
+
+/**
+ * Helper function to gather namespaces from QNames or namespace prefixes, plus a few extra for the
+ * remaining request.
+ *
+ * @param {...string} aTags - Either QNames, or just namespace prefixes to be resolved.
+ * @returns {string} The complete namespace string
+ */
+function CalDavTagsToXmlns(...aTags) {
+  let namespaces = new Set(aTags.map(tag => tag.split(":")[0]));
+  return CalDavXmlns(...namespaces.values());
+}
+
+/**
+ * Resolve the namespace URI to one of the prefixes used in our codebase
+ *
+ * @param {string} aNamespace - The namespace URI to resolve
+ * @returns {?string} The namespace prefix we use
+ */
+function CalDavNsUnresolver(aNamespace) {
+  const prefixes = {
+    "http://apple.com/ns/ical/": "A",
+    "DAV:": "D",
+    "urn:ietf:params:xml:ns:caldav": "C",
+    "http://calendarserver.org/ns/": "CS",
+  };
+  return prefixes[aNamespace] || null;
+}
+
+/**
+ * Resolve the namespace URI from one of the prefixes used in our codebase
+ *
+ * @param {string} aPrefix - The namespace prefix we use
+ * @returns {?string} The namespace URI for the prefix
+ */
+function CalDavNsResolver(aPrefix) {
+  /* eslint-disable id-length */
+  const namespaces = {
+    A: "http://apple.com/ns/ical/",
+    D: "DAV:",
+    C: "urn:ietf:params:xml:ns:caldav",
+    CS: "http://calendarserver.org/ns/",
+  };
+  /* eslint-enable id-length */
+
+  return namespaces[aPrefix] || null;
+}
+
+/**
+ * Run an xpath expression on the given node, using the caldav namespace resolver
+ *
+ * @param {Element} aNode - The context node to search from
+ * @param {string} aExpr - The XPath expression to search for
+ * @param {?XPathResult} aType - (optional) Force a result type, must be an XPathResult constant
+ * @returns {Element[]} Array of found elements
+ */
+function CalDavXPath(aNode, aExpr, aType) {
+  return cal.xml.evalXPath(aNode, aExpr, CalDavNsResolver, aType);
+}
+
+/**
+ * Run an xpath expression on the given node, using the caldav namespace resolver. Returns the first
+ * result.
+ *
+ * @param {Element} aNode - The context node to search from
+ * @param {string} aExpr - The XPath expression to search for
+ * @param {?XPathResult} aType - (optional) Force a result type, must be an XPathResult constant
+ * @returns {?Element} The found element, or null.
+ */
+function CalDavXPathFirst(aNode, aExpr, aType) {
+  return cal.xml.evalXPathFirst(aNode, aExpr, CalDavNsResolver, aType);
+}