Add regex validating field

static/js/directives/ui/regex-editor.js

@@ -0,0 +1,39 @@
+/**
+ * An element which displays an edit box for regular expressions.
+ */
+angular.module('quay').directive('regexEditor', function () {
+  var directiveDefinitionObject = {
+    priority: 0,
+    templateUrl: '/static/directives/regex-editor.html',
+    replace: false,
+    transclude: true,
+    restrict: 'C',
+    scope: {
+      'placeholder': '@placeholder',
+      'optional': '=optional',
+      'binding': '=binding'
+    },
+    controller: function($scope, $element) {
+    }
+  };
+  return directiveDefinitionObject;
+});
+
+angular.module('quay').directive('requireValidRegex', function() {
+  return {
+    require: 'ngModel',
+    link: function(scope, element, attr, ctrl) {
+      function validator(value) {
+        try {
+          new RegExp(value)
+          ctrl.$setValidity('regex', true);
+        } catch (e) {
+          ctrl.$setValidity('regex', false);
+        }
+        return value;
+      }
+
+      ctrl.$parsers.push(validator);
+    }
+  };
+});

static/js/services/external-notification-data.js

@@ -45,6 +45,7 @@ function(Config, Features, VulnerabilityService) {
             'help_text': 'An optional regular expression for matching the git branch or tag ' +
                          'git ref. If left blank, the notification will fire for all builds.',
             'optional': true,
+            'placeholder': '(refs/heads/somebranch)|(refs/tags/sometag)'
           }
         ]
       },
@@ -60,6 +61,7 @@ function(Config, Features, VulnerabilityService) {
             'help_text': 'An optional regular expression for matching the git branch or tag ' +
                          'git ref. If left blank, the notification will fire for all builds.',
             'optional': true,
+            'placeholder': '(refs/heads/somebranch)|(refs/tags/sometag)'
           }
         ]
       },
@@ -75,6 +77,7 @@ function(Config, Features, VulnerabilityService) {
             'help_text': 'An optional regular expression for matching the git branch or tag ' +
                          'git ref. If left blank, the notification will fire for all builds.',
             'optional': true,
+            'placeholder': '(refs/heads/somebranch)|(refs/tags/sometag)'
           }
         ]
       }];