Creating "contenttype" rule for layers

--HG--
branch : 1.x

src/Orchard.Web/Modules/Orchard.Widgets/Handlers/DisplayedContentItemHandler.cs

@@ -0,0 +1,25 @@
+using System.Collections.ObjectModel;
+using Orchard.ContentManagement.Handlers;
+
+namespace Orchard.Widgets.Handlers {
+    /// <summary>
+    /// Saves references to content items which have been displayed during a request
+    /// </summary>
+    public class DisplayedContentItemDetailHandler : ContentHandler, IDisplayedContentItemHandler {
+        private readonly Collection<string> _contentTypes = new Collection<string>();
+
+        protected override void BuildDisplayShape(BuildDisplayContext context) {
+            if (context.DisplayType == "Detail") {
+                _contentTypes.Add(context.ContentItem.ContentType);
+            }
+        }
+
+        public bool IsDisplayed(string contentType) {
+            return _contentTypes.Contains(contentType);
+        }
+    }
+
+    public interface IDisplayedContentItemHandler: IDependency {
+        bool IsDisplayed(string contentType);
+    }
+}

src/Orchard.Web/Modules/Orchard.Widgets/Orchard.Widgets.csproj

@@ -63,6 +63,7 @@
     <Compile Include="Controllers\AdminController.cs" />
     <Compile Include="ControlWrapper.cs" />
     <Compile Include="Drivers\LayerPartDriver.cs" />
+    <Compile Include="Handlers\DisplayedContentItemHandler.cs" />
     <Compile Include="Handlers\LayerHintHandler.cs" />
     <Compile Include="Drivers\WidgetPartDriver.cs" />
     <Compile Include="Migrations.cs" />
@@ -78,6 +79,7 @@
     <Compile Include="ResourceManifest.cs" />
     <Compile Include="RuleEngine\AuthenticatedRuleProvider.cs" />
     <Compile Include="RuleEngine\BuiltinRuleProvider.cs" />
+    <Compile Include="RuleEngine\ContentDisplayedRuleProvider.cs" />
     <Compile Include="RuleEngine\RuleManager.cs" />
     <Compile Include="RuleEngine\UrlRuleProvider.cs" />
     <Compile Include="Services\IRuleManager.cs" />

src/Orchard.Web/Modules/Orchard.Widgets/RuleEngine/ContentDisplayedRuleProvider.cs

@@ -0,0 +1,23 @@
+using System;
+using Orchard.Widgets.Handlers;
+using Orchard.Widgets.Services;
+
+namespace Orchard.Widgets.RuleEngine {
+    public class ContentDisplayedRuleProvider : IRuleProvider {
+        private readonly IDisplayedContentItemHandler _displayedContentItemHandler;
+
+        public ContentDisplayedRuleProvider(IDisplayedContentItemHandler displayedContentItemHandler) {
+            _displayedContentItemHandler = displayedContentItemHandler;
+        }
+
+        public void Process(RuleContext ruleContext) { 
+            if (!String.Equals(ruleContext.FunctionName, "contenttype", StringComparison.OrdinalIgnoreCase)) {
+                return;
+            }
+
+            var contentType = Convert.ToString(ruleContext.Arguments[0]);
+
+            ruleContext.Result = _displayedContentItemHandler.IsDisplayed(contentType);
+        }
+    }
+}