Introducing display-time events to shape rendering

Shape specific events can be hooked with ShapeDescriptor Displaying and Displayed delegate arrays
Events for every shape can be hooked with IShapeDisplayEvents Displaying and Displayed methods

--HG--
branch : dev

src/Orchard.Tests/DisplayManagement/DefaultDisplayManagerTests.cs

@@ -32,10 +32,22 @@ namespace Orchard.Tests.DisplayManagement {
             builder.RegisterType<DefaultDisplayManager>().As<IDisplayManager>();
             builder.RegisterType<TestShapeTableManager>().As<IShapeTableManager>();
             builder.RegisterType<TestWorkContextAccessor>().As<IWorkContextAccessor>();
+            builder.RegisterType<TestDisplayEvents>().As<IShapeDisplayEvents>()
+                .As<TestDisplayEvents>()
+                .InstancePerLifetimeScope();
+
             builder.Register(ctx => _defaultShapeTable);
             builder.Register(ctx => _workContext);
         }
 
+        class TestDisplayEvents : IShapeDisplayEvents {
+            public Action<ShapeDisplayingContext> Displaying = ctx => { };
+            public Action<ShapeDisplayedContext> Displayed = ctx => { };
+
+            void IShapeDisplayEvents.Displaying(ShapeDisplayingContext context) { Displaying(context); }
+            void IShapeDisplayEvents.Displayed(ShapeDisplayedContext context) { Displayed(context); }
+        }
+
         public class Theme : ITheme {
             public string ThemeName { get; set; }
             public string DisplayName { get; set; }
@@ -209,22 +221,108 @@ namespace Orchard.Tests.DisplayManagement {
             var descriptor = new ShapeDescriptor {
                 ShapeType = "Foo",
             };
-            descriptor.Bindings["Foo"] = new ShapeBinding {
-                BindingName = "Foo",
-                Binding = ctx => new HtmlString("Hi there!"),
-            };
-            descriptor.Bindings["Foo__1"] = new ShapeBinding {
-                BindingName = "Foo__1",
-                Binding = ctx => new HtmlString("Hello (1)!"),
-            };
-            descriptor.Bindings["Foo__2"] = new ShapeBinding {
-                BindingName = "Foo__2",
-                Binding = ctx => new HtmlString("Hello (2)!"),
-            };
+            AddBinding(descriptor, "Foo", ctx => new HtmlString("Hi there!"));
+            AddBinding(descriptor, "Foo__1", ctx => new HtmlString("Hello (1)!"));
+            AddBinding(descriptor, "Foo__2", ctx => new HtmlString("Hello (2)!"));
             AddShapeDescriptor(descriptor);
 
             var result = displayManager.Execute(CreateDisplayContext(shape));
             Assert.That(result.ToString(), Is.EqualTo("Hello (2)!"));
         }
+
+        private static void AddBinding(ShapeDescriptor descriptor, string bindingName, Func<DisplayContext, IHtmlString> binding) {
+            descriptor.Bindings[bindingName] = new ShapeBinding {
+                BindingName = bindingName,
+                Binding = binding,
+            };
+        }
+
+
+        [Test]
+        public void IShapeDisplayEventsIsCalled() {
+            var displayManager = _container.Resolve<IDisplayManager>();
+
+            var shape = new Shape {
+                Metadata = new ShapeMetadata {
+                    Type = "Foo"
+                }
+            };
+
+            var descriptor = new ShapeDescriptor {
+                ShapeType = "Foo",
+            };
+            AddBinding(descriptor, "Foo", ctx => new HtmlString("yarg"));
+            AddShapeDescriptor(descriptor);
+
+            var displayingEventCount = 0;
+            var displayedEventCount = 0;
+            _container.Resolve<TestDisplayEvents>().Displaying = ctx => { ++displayingEventCount; };
+            _container.Resolve<TestDisplayEvents>().Displayed = ctx => { ++displayedEventCount; ctx.ChildContent = new HtmlString("[" + ctx.ChildContent.ToHtmlString() + "]"); };
+
+            var result = displayManager.Execute(CreateDisplayContext(shape));
+
+            Assert.That(displayingEventCount, Is.EqualTo(1));
+            Assert.That(displayedEventCount, Is.EqualTo(1));
+            Assert.That(result.ToString(), Is.EqualTo("[yarg]"));
+        }
+
+
+        [Test]
+        public void ShapeDescriptorDisplayingAndDisplayedAreCalled() {
+            var displayManager = _container.Resolve<IDisplayManager>();
+
+            var shape = new Shape {
+                Metadata = new ShapeMetadata {
+                    Type = "Foo"
+                }
+            };
+
+            var descriptor = new ShapeDescriptor {
+                ShapeType = "Foo",
+            };
+            AddBinding(descriptor, "Foo", ctx => new HtmlString("yarg"));
+            AddShapeDescriptor(descriptor);
+
+            var displayingEventCount = 0;
+            var displayedEventCount = 0;
+            descriptor.Displaying = new Action<ShapeDisplayingContext>[] { ctx => { ++displayingEventCount; } };
+            descriptor.Displayed = new Action<ShapeDisplayedContext>[] { ctx => { ++displayedEventCount; ctx.ChildContent = new HtmlString("[" + ctx.ChildContent.ToHtmlString() + "]"); } };
+
+            var result = displayManager.Execute(CreateDisplayContext(shape));
+
+            Assert.That(displayingEventCount, Is.EqualTo(1));
+            Assert.That(displayedEventCount, Is.EqualTo(1));
+            Assert.That(result.ToString(), Is.EqualTo("[yarg]"));
+        }
+
+        [Test]
+        public void DisplayingEventFiresEarlyEnoughToAddAlternateShapeBindingNames() {
+            var displayManager = _container.Resolve<IDisplayManager>();
+
+            var shapeFoo = new Shape {
+                Metadata = new ShapeMetadata {
+                    Type = "Foo"
+                }
+            };
+            var descriptorFoo = new ShapeDescriptor {
+                ShapeType = "Foo",
+            };
+            AddBinding(descriptorFoo, "Foo", ctx => new HtmlString("alpha"));
+            AddShapeDescriptor(descriptorFoo);
+
+            var descriptorBar = new ShapeDescriptor {
+                ShapeType = "Bar",
+            };
+            AddBinding(descriptorBar, "Bar", ctx => new HtmlString("beta"));
+            AddShapeDescriptor(descriptorBar);
+
+
+            var resultNormally = displayManager.Execute(CreateDisplayContext(shapeFoo));
+            descriptorFoo.Displaying = new Action<ShapeDisplayingContext>[] { ctx => ctx.ShapeMetadata.Alternates.Add("Bar") };
+            var resultWithOverride = displayManager.Execute(CreateDisplayContext(shapeFoo));
+
+            Assert.That(resultNormally.ToString(), Is.EqualTo("alpha"));
+            Assert.That(resultWithOverride.ToString(), Is.EqualTo("beta"));
+        }
     }
 }