feat($compile): optionally get controllers from ancestors only

Implement option to strengthen require '^' operator, by adding another '^'.

When a second '^' is used, the controller will only search parent nodes for the
matching controller, and will throw or return null if not found, depending on
whether or not the requirement is optional.

Closes #4518

Author: Caitlin Potter

Diff for: src/ng/compile.js

@@ -502,7 +502,9 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
   var hasDirectives = {},
       Suffix = 'Directive',
       COMMENT_DIRECTIVE_REGEXP = /^\s*directive\:\s*([\d\w\-_]+)\s+(.*)$/,
-      CLASS_DIRECTIVE_REGEXP = /(([\d\w\-_]+)(?:\:([^;]+))?;?)/;
+      CLASS_DIRECTIVE_REGEXP = /(([\d\w\-_]+)(?:\:([^;]+))?;?)/,
+      REQUIRE_PREFIX_REGEXP = /(\?)|(\^\^?)/g,
+      REQUIRE_PREFIX_PRE_REGEXP = /^((\?)|(\^\^?))+/;
 
   // Ref: http://developers.whatwg.org/webappapis.html#event-handler-idl-attributes
   // The assumption is that future DOM event attribute names will begin with
@@ -1343,21 +1345,27 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
 
 
       function getControllers(require, $element, elementControllers) {
-        var value, retrievalMethod = 'data', optional = false;
+        var value, retrievalMethod = 'data', optional = false, search = $element, prematch, match;
         if (isString(require)) {
-          while((value = require.charAt(0)) == '^' || value == '?') {
-            require = require.substr(1);
-            if (value == '^') {
-              retrievalMethod = 'inheritedData';
+          if ((prematch = require.match(REQUIRE_PREFIX_PRE_REGEXP)) &&
+              (match = prematch[0].match(REQUIRE_PREFIX_REGEXP))) {
+            for (var i=0, ii=match.length; i<ii; ++i) {
+              value = match[i];
+              switch (value) {
+                case '^': retrievalMethod = 'inheritedData'; break;
+                case '^^': retrievalMethod = 'inheritedData'; search = $element.parent(); break;
+                case '?': optional = true; break;
+              }
             }
-            optional = optional || value == '?';
+
+            require = require.substring(prematch[0].length);
           }
           value = null;
 
           if (elementControllers && retrievalMethod === 'data') {
             value = elementControllers[require];
           }
-          value = value || $element[retrievalMethod]('$' + require + 'Controller');
+          value = value || search[retrievalMethod]('$' + require + 'Controller');
 
           if (!value && !optional) {
             throw $compileMinErr('ctreq',

Diff for: test/ng/compileSpec.js

@@ -2680,6 +2680,43 @@ describe('$compile', function() {
     });
 
 
+    it('should get required parent controller', function() {
+      module(function() {
+        directive('nested', function(log) {
+          return {
+            require: '^^?nested',
+            controller: function($scope) {},
+            link: function(scope, element, attrs, controller) {
+              log(!!controller);
+            }
+          };
+        });
+      });
+      inject(function(log, $compile, $rootScope) {
+        element = $compile('<div nested><div nested></div></div>')($rootScope);
+        expect(log).toEqual('true; false');
+      });
+    });
+
+
+    it('should throw if required parent is not found', function() {
+      module(function() {
+        directive('nested', function() {
+          return {
+            require: '^^nested',
+            controller: function($scope) {},
+            link: function(scope, element, attrs, controller) {}
+          };
+        });
+      });
+      inject(function($compile, $rootScope) {
+        expect(function() {
+          element = $compile('<div nested></div>')($rootScope);
+        }).toThrowMinErr('$compile', 'ctreq', "Controller 'nested', required by directive 'nested', can't be found!");
+      });
+    })
+
+
     it('should get required controller via linkingFn (template)', function() {
       module(function() {
         directive('dirA', function() {