Trivial server side extensible search filter support

lib/filters/ext_filter.js

@@ -82,12 +82,49 @@ ExtensibleFilter.prototype.matches = function(target) {
   if (typeof(target) !== 'object')
     throw new TypeError('target (object) required');
 
+  if (this.dnAttribute)
+    throw new Error('ExtensibleMatch dnAttributes not supported');
+
+  if (!this.value)
+    return false;
+
+  var self = this;
+  if (this.matchType && target.hasOwnProperty(this.matchType)) {
+    return Filter.multi_test(function(v) {
+      if (self.rule === '2.5.13.2')
+        return self.value.toLowerCase() === v.toLowerCase();
+
+      return self.value === v;
+    }, target[this.matchType]);
+  }
+
   return false;
 };
 
 
 ExtensibleFilter.prototype.parse = function(ber) {
-  throw new Error('ExtensibleFilter not supported');
+  var end = ber.offset + ber.length;
+  while (ber.offset < end) {
+    var tag = ber.peek();
+    switch (tag) {
+    case 0x81:
+      this.rule = ber.readString(tag);
+      break;
+    case 0x82:
+      this.matchType = ber.readString(tag);
+      break;
+    case 0x83:
+      this.value = ber.readString(tag);
+      break;
+    case 0x84:
+      this.dnAttributes = ber.readBoolean(tag);
+      break;
+    default:
+      throw new Error('Invalid ext_match filter type: 0x' + tag.toString(16));
+    }
+  }
+
+  return true;
 };