Adding OrchardDependencyReplace attribute

--HG--
branch : dev

src/Orchard.Tests/Environment/DefaultCompositionStrategyTests.cs

@@ -7,6 +7,7 @@ using Autofac;
 using Autofac.Core;
 using Moq;
 using NUnit.Framework;
+using Orchard.ContentManagement;
 using Orchard.ContentManagement.Records;
 using Orchard.Environment;
 using Orchard.Environment.Configuration;
@@ -294,5 +295,32 @@ namespace Orchard.Tests.Environment {
             Assert.That(bar.TableName, Is.EqualTo("Yadda_Bar_BarRecord"));
         }
 
+        [Test]
+        public void FeatureReplacement() {
+            var descriptor = Build.ShellDescriptor().WithFeatures("Bar");
+
+            _extensionDescriptors = new[] {
+                Build.ExtensionDescriptor("Foo").WithFeatures("Bar"),
+            };
+
+            _featureTypes["Bar"] = new[] { typeof(ReplacedStubType), typeof(StubType), typeof(ReplacedStubNestedType), typeof(StubNestedType) };
+
+            var compositionStrategy = _container.Resolve<ICompositionStrategy>();
+            var blueprint = compositionStrategy.Compose(BuildDefaultSettings(), descriptor);
+
+            Assert.That(blueprint.Dependencies.Count(), Is.EqualTo(2));
+            Assert.That(blueprint.Dependencies.FirstOrDefault(dependency => dependency.Type.Equals(typeof(StubType))), Is.Not.Null);
+            Assert.That(blueprint.Dependencies.FirstOrDefault(dependency => dependency.Type.Equals(typeof(StubNestedType))), Is.Not.Null);
+        }
+
+        [OrchardDependencyReplace("Orchard.Tests.Environment.DefaultCompositionStrategyTests+ReplacedStubNestedType")]
+        internal class StubNestedType : IDependency {}
+
+        internal class ReplacedStubNestedType : IDependency {}
     }
+
+    [OrchardDependencyReplace("Orchard.Tests.Environment.ReplacedStubType")]
+    internal class StubType : IDependency { }
+
+    internal class ReplacedStubType : IDependency { }
 }

src/Orchard/Environment/Extensions/OrchardDependencyReplaceAttribute.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace Orchard.Environment.Extensions {
+    [AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = false)]
+    public class OrchardDependencyReplaceAttribute : Attribute {
+        public OrchardDependencyReplaceAttribute(string dependency) {
+            Dependency = dependency;
+        }
+
+        public string Dependency { get; set; }
+    }
+}

src/Orchard/Environment/ShellBuilders/CompositionStrategy.cs

@@ -72,9 +72,22 @@ namespace Orchard.Environment.ShellBuilders {
             IEnumerable<Feature> features,
             Func<Type, bool> predicate,
             Func<Type, Feature, T> selector) {
+            HashSet<string> excludedTypes = new HashSet<string>();
+
+            // Identify replaced types
+            foreach(Feature feature in features) {
+                foreach (Type type in feature.ExportedTypes) {
+                    foreach (OrchardDependencyReplaceAttribute replacedType in type.GetCustomAttributes(typeof(OrchardDependencyReplaceAttribute), false)) {
+                        excludedTypes.Add(replacedType.Dependency);
+                    }
+                }
+            }
+
+            // Load types excluding the replaced types
             return features.SelectMany(
                 feature => feature.ExportedTypes
                                .Where(predicate)
+                               .Where(type => !excludedTypes.Contains(type.FullName))
                                .Select(type => selector(type, feature)))
                 .ToArray();
         }