fix($compile): use the correct namespace for transcluded svg elements

Via transclusion, svg elements can occur outside an `<svg>` container in an
Angular template but are put into an `<svg>` container through compilation
and linking.

E.g.
Given that `svg-container` is a transcluding directive with
the following template:
```
<svg ng-transclude></svg>
```

The following markup creates a `<circle>` inside of an `<svg>` element
during runtime:
```
<svg-container>
  <circle></circle>
</svg-container>
```

However, this produces non working `<circle>` elements, as svg elements
need to be created inside of an `<svg>` element.

This change detects for most cases the correct namespace of transcluded content
and recreates that content in the correct `<svg>` container
when needed during compilation. For special cases it adds an addition argument
to `$transclude` that allows to specify the future parent node of elements
that will be cloned and attached using the `cloneAttachFn`.

Related to angular#8494

Author: tbosch

src/ng/compile.js

@@ -185,9 +185,18 @@
  * * `$scope` - Current scope associated with the element
  * * `$element` - Current element
  * * `$attrs` - Current attributes object for the element
- * * `$transclude` - A transclude linking function pre-bound to the correct transclusion scope.
- *    The scope can be overridden by an optional first argument.
- *   `function([scope], cloneLinkingFn)`.
+ * * `$transclude` - A transclude linking function pre-bound to the correct transclusion scope:
+ *   `function([scope], cloneLinkingFn, futureParentNode)`.
+ *    * `scope`: optional argument to override the scope.
+ *    * `cloneLinkingFn`: optional argument to create clones of the original translcuded content.
+ *    * `futureParentNode`:
+ *        * defines the parent to which the `cloneLinkingFn` will add the cloned elements.
+ *        * default: `$element.parent()` resp. `$element` for `transclude:'element'` resp. `transclude:true`.
+ *        * only needed for transcludes that are allowed to contain non html elements (e.g. SVG elements)
+ *          and when the `cloneLinkinFn` is passed,
+ *          as those elements need to created and cloned in a special way when they are defined outside their
+ *          usual containers (e.g. like `<svg>`).
+ *        * See also the `directive.templateNamespace` property.
  *
  *
  * #### `require`
@@ -265,6 +274,10 @@
  * one. See the {@link guide/directive#creating-custom-directives_creating-directives_template-expanding-directive
  * Directives Guide} for an example.
  *
+ * There very few scenarios were element replacement is required for the application function,
+ * the main one being reusable custom components that are used within SVG contexts
+ * (because SVG doesn't work with custom elements in the DOM tree).
+ *
  * #### `transclude`
  * compile the content of the element and make it available to the directive.
  * Typically used with {@link ng.directive:ngTransclude
@@ -359,10 +372,9 @@
  *     the directives to use the controllers as a communication channel.
  *
  *   * `transcludeFn` - A transclude linking function pre-bound to the correct transclusion scope.
- *     The scope can be overridden by an optional first argument. This is the same as the `$transclude`
- *     parameter of directive controllers.
- *     `function([scope], cloneLinkingFn)`.
- *
+ *     This is the same as the `$transclude`
+ *     parameter of directive controllers, see there for details.
+ *     `function([scope], cloneLinkingFn, futureParentNode)`.
  *
  * #### Pre-linking function
  *
@@ -879,8 +891,18 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
               compileNodes($compileNodes, transcludeFn, $compileNodes,
                            maxPriority, ignoreDirective, previousCompileContext);
       safeAddClass($compileNodes, 'ng-scope');
-      return function publicLinkFn(scope, cloneConnectFn, transcludeControllers, parentBoundTranscludeFn){
+      var namespace = null;
+      return function publicLinkFn(scope, cloneConnectFn, transcludeControllers, parentBoundTranscludeFn, futureParentNode){
         assertArg(scope, 'scope');
+        if (!namespace) {
+          namespace = detectNamespaceForChildElements(futureParentNode);
+          if (namespace !== 'html') {
+            $compileNodes = jqLite(
+              wrapTemplate(namespace, jqLite('<div>').append($compileNodes).html())
+            );
+          }
+        }
+
         // important!!: we must call our jqLite.clone() since the jQuery one is trying to be smart
         // and sometimes changes the structure of the DOM.
         var $linkNode = cloneConnectFn
@@ -901,6 +923,16 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
       };
     }
 
+    function detectNamespaceForChildElements(parentElement) {
+      // TODO: Make this detect MathML as well...
+      var node = parentElement && parentElement[0];
+      if (!node) {
+        return 'html';
+      } else {
+        return node.nodeName !== 'foreignObject' && node.toString().match(/SVG/) ? 'svg': 'html';
+      }
+    }
+
     function safeAddClass($element, className) {
       try {
         $element.addClass(className);
@@ -1024,7 +1056,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
 
     function createBoundTranscludeFn(scope, transcludeFn, previousBoundTranscludeFn, elementTransclusion) {
 
-      var boundTranscludeFn = function(transcludedScope, cloneFn, controllers) {
+      var boundTranscludeFn = function(transcludedScope, cloneFn, controllers, futureParentNode) {
         var scopeCreated = false;
 
         if (!transcludedScope) {
@@ -1033,7 +1065,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
           scopeCreated = true;
         }
 
-        var clone = transcludeFn(transcludedScope, cloneFn, controllers, previousBoundTranscludeFn);
+        var clone = transcludeFn(transcludedScope, cloneFn, controllers, previousBoundTranscludeFn, futureParentNode);
         if (scopeCreated && !elementTransclusion) {
           clone.on('$destroy', function() { transcludedScope.$destroy(); });
         }
@@ -1645,20 +1677,24 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
         }
 
         // This is the function that is injected as `$transclude`.
-        function controllersBoundTransclude(scope, cloneAttachFn) {
+        // Note: all arguments are optional!
+        function controllersBoundTransclude(scope, cloneAttachFn, futureParentNode) {
           var transcludeControllers;
 
-          // no scope passed
-          if (!cloneAttachFn) {
+          // No scope passed in:
+          if (!isScope(scope)) {
+            futureParentNode = cloneAttachFn;
             cloneAttachFn = scope;
             scope = undefined;
           }
 
           if (hasElementTranscludeDirective) {
             transcludeControllers = elementControllers;
           }
-
-          return boundTranscludeFn(scope, cloneAttachFn, transcludeControllers);
+          if (!futureParentNode) {
+            futureParentNode = hasElementTranscludeDirective ? $element.parent() : $element;
+          }
+          return boundTranscludeFn(scope, cloneAttachFn, transcludeControllers, futureParentNode);
         }
       }
     }

test/ng/compileSpec.js

@@ -63,6 +63,32 @@ describe('$compile', function() {
       terminal: true
     }));
 
+    directive('svgContainer', function() {
+      return {
+        template: '<svg width="400" height="400" ng-transclude></svg>',
+        replace: true,
+        transclude: true
+      };
+    });
+
+    directive('svgCircle', function(){
+      return {
+        template: '<circle cx="2" cy="2" r="1"></circle>',
+        templateNamespace: 'svg',
+        replace: true
+      };
+    });
+
+    directive('myForeignObject', function(){
+      return {
+        template: '<foreignObject width="100" height="100" ng-transclude></foreignObject>',
+        templateNamespace: 'svg',
+        replace: true,
+        transclude: true
+      };
+    });
+
+
     return function(_$compile_, _$rootScope_) {
       $rootScope = _$rootScope_;
       $compile = _$compile_;
@@ -137,6 +163,91 @@ describe('$compile', function() {
   });
 
 
+  describe('svg namespace transcludes', function() {
+    // this method assumes some sort of sized SVG element is being inspected.
+    function assertIsValidSvgCircle(elem) {
+      var unknownElement = Object.prototype.toString.call(elem) === '[object HTMLUnknownElement]';
+      expect(unknownElement).toBe(false);
+      var box = elem.getBoundingClientRect();
+      expect(box.width === 0 && box.height === 0).toBe(false);
+    }
+
+    it('should handle transcluded svg elements', inject(function($compile){
+      element = jqLite('<div><svg-container>' +
+          '<circle cx="4" cy="4" r="2"></circle>' +
+          '</svg-container></div>');
+      $compile(element.contents())($rootScope);
+      document.body.appendChild(element[0]);
+
+      var circle = element.find('circle');
+
+      assertIsValidSvgCircle(circle[0]);
+    }));
+
+    it('should handle custom svg elements inside svg tag', function(){
+      element = jqLite('<div><svg width="300" height="300">' +
+          '<svg-circle></svg-circle>' +
+          '</svg></div>');
+      $compile(element.contents())($rootScope);
+      document.body.appendChild(element[0]);
+
+      var circle = element.find('circle');
+      assertIsValidSvgCircle(circle[0]);
+    });
+
+    it('should handle transcluded custom svg elements', inject(function(){
+      element = jqLite('<div><svg-container>' +
+          '<svg-circle></svg-circle>' +
+          '</svg-container></div>');
+      $compile(element.contents())($rootScope);
+      document.body.appendChild(element[0]);
+
+      var circle = element.find('circle');
+      assertIsValidSvgCircle(circle[0]);
+    }));
+
+    it('should handle foreignObject', inject(function(){
+      element = jqLite('<div><svg-container>' +
+          '<foreignObject width="100" height="100"><div class="test" style="width:20px;height:20px">test</div></foreignObject>' +
+          '</svg-container></div>');
+      $compile(element.contents())($rootScope);
+      document.body.appendChild(element[0]);
+
+      var testElem = element.find('div');
+      expect(testElem[0].toString()).toBe('[object HTMLDivElement]');
+      var bounds = testElem[0].getBoundingClientRect();
+      expect(bounds.width === 20 && bounds.height === 20).toBe(true);
+    }));
+
+    it('should handle custom svg containers that transclude to foreignObject that transclude html', inject(function(){
+      element = jqLite('<div><svg-container>' +
+          '<my-foreign-object><div class="test" style="width:20px;height:20px">test</div></my-foreign-object>' +
+          '</svg-container></div>');
+      $compile(element.contents())($rootScope);
+      document.body.appendChild(element[0]);
+
+      var testElem = element.find('div');
+      expect(testElem[0].toString()).toBe('[object HTMLDivElement]');
+      var bounds = testElem[0].getBoundingClientRect();
+      expect(bounds.width === 20 && bounds.height === 20).toBe(true);
+    }));
+
+    // NOTE: This test may be redundant.
+    it('should handle custom svg containers that transclude to foreignObject'+
+       ' that transclude to custom svg containers that transclude to custom elements', inject(function(){
+      element = jqLite('<div><svg-container>' +
+          '<my-foreign-object><svg-container><svg-circle></svg-circle></svg-container></my-foreign-object>' +
+          '</svg-container></div>');
+      $compile(element.contents())($rootScope);
+      document.body.appendChild(element[0]);
+
+      var circle = element.find('circle');
+      assertIsValidSvgCircle(circle[0]);
+    }));
+
+  });
+
+
   describe('compile phase', function() {
 
     it('should attach scope to the document node when it is compiled explicitly', inject(function($document){

test/ng/directive/ngIfSpec.js

@@ -351,4 +351,23 @@ describe('ngIf animations', function () {
     });
   });
 
+  it('should work with svg elements when the svg container is transcluded', function() {
+    module(function($compileProvider) {
+      $compileProvider.directive('svgContainer', function() {
+        return {
+          template: '<svg ng-transclude></svg>',
+          replace: true,
+          transclude: true
+        };
+      });
+    });
+    inject(function($compile, $rootScope) {
+      element = $compile('<svg-container><circle ng-if="flag"></circle></svg-container>')($rootScope);
+      $rootScope.flag = true;
+      $rootScope.$apply();
+
+      var circle = element.find('circle');
+      expect(circle[0].toString()).toMatch(/SVG/);
+    });
+  });
 });

test/ng/directive/ngRepeatSpec.js

@@ -1387,4 +1387,24 @@ describe('ngRepeat animations', function() {
     })
   );
 
+  it('should work with svg elements when the svg container is transcluded', function() {
+    module(function($compileProvider) {
+      $compileProvider.directive('svgContainer', function() {
+        return {
+          template: '<svg ng-transclude></svg>',
+          replace: true,
+          transclude: true
+        };
+      });
+    });
+    inject(function($compile, $rootScope) {
+      element = $compile('<svg-container><circle ng-repeat="r in rows"></circle></svg-container>')($rootScope);
+      $rootScope.rows = [1];
+      $rootScope.$apply();
+
+      var circle = element.find('circle');
+      expect(circle[0].toString()).toMatch(/SVG/);
+    });
+  });
+
 });

test/ng/directive/ngSwitchSpec.js

@@ -433,4 +433,25 @@ describe('ngSwitch animations', function() {
       expect(destroyed).toBe(true);
     });
   });
+
+  it('should work with svg elements when the svg container is transcluded', function() {
+    module(function($compileProvider) {
+      $compileProvider.directive('svgContainer', function() {
+        return {
+          template: '<svg ng-transclude></svg>',
+          replace: true,
+          transclude: true
+        };
+      });
+    });
+    inject(function($compile, $rootScope) {
+      element = $compile('<svg-container ng-switch="inc"><circle ng-switch-when="one"></circle>' +
+        '</svg-container>')($rootScope);
+      $rootScope.inc = 'one';
+      $rootScope.$apply();
+
+      var circle = element.find('circle');
+      expect(circle[0].toString()).toMatch(/SVG/);
+    });
+  });
 });