Include V8 JavaScript engine (ClearScript/VroomJs) as standard in React.Core

Author: Daniel15

build.proj

@@ -31,8 +31,6 @@ of patent rights can be found in the PATENTS file in the same directory.
 		<PackageAssemblies Include="System.Web.Optimization.React" />
 		<PackageAssemblies Include="Cassette.React" />
 		<PackageAssemblies Include="React.MSBuild" />
-		<PackageAssemblies Include="React.JavaScriptEngine.VroomJs" />
-		<PackageAssemblies Include="React.JavaScriptEngine.ClearScriptV8" />
 		<PackageAssembliesAspNet5 Include="React.AspNet" />
 		<AspNet5ProjectJson Include="src/**/project.json" />
 	</ItemGroup>

src/React.AspNet/React.AspNet.kproj

@@ -17,6 +17,9 @@
   <PropertyGroup>
     <SchemaVersion>2.0</SchemaVersion>
   </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\React.Core\React.Core.csproj" />
+  </ItemGroup>
   <Import Project="$(VSToolsPath)\AspNet\Microsoft.Web.AspNet.targets" Condition="'$(VSToolsPath)' != ''" />
   <ProjectExtensions>
     <VisualStudio>

src/React.Core/AssemblyRegistration.cs

@@ -7,9 +7,9 @@
  *  of patent rights can be found in the PATENTS file in the same directory.
  */
 
-using JavaScriptEngineSwitcher.Jint;
 using JavaScriptEngineSwitcher.Msie;
 using JavaScriptEngineSwitcher.Msie.Configuration;
+using JavaScriptEngineSwitcher.V8;
 using React.TinyIoC;
 
 namespace React
@@ -40,23 +40,47 @@ public void Register(TinyIoCContainer container)
 			container.Register<IJavaScriptEngineFactory, JavaScriptEngineFactory>().AsSingleton();
 
 			container.Register<IReactEnvironment, ReactEnvironment>().AsPerRequestSingleton();
+			RegisterSupportedEngines(container);
+		}
+
+		/// <summary>
+		/// Registers JavaScript engines that may be able to run in the current environment
+		/// </summary>
+		/// <param name="container"></param>
+		private void RegisterSupportedEngines(TinyIoCContainer container)
+		{
+			if (JavaScriptEngineUtils.EnvironmentSupportsClearScript())
+			{
+				container.Register(new JavaScriptEngineFactory.Registration
+				{
+					Factory = () => new V8JsEngine(),
+					Priority = 10
+				}, "ClearScriptV8");
+			}
+			if (JavaScriptEngineUtils.EnvironmentSupportsVroomJs())
+			{
+				container.Register(new JavaScriptEngineFactory.Registration
+				{
+					Factory = () => new VroomJsEngine(),
+					Priority = 10
+				}, "VroomJs");
+			}
 
-			// JavaScript engines
 			container.Register(new JavaScriptEngineFactory.Registration
 			{
-				Factory = () => new MsieJsEngine(new MsieConfiguration { EngineMode = JsEngineMode.ChakraActiveScript }),
+				Factory = () => new MsieJsEngine(new MsieConfiguration { EngineMode = JsEngineMode.ChakraJsRt }),
 				Priority = 20
-			}, "MsieChakra");
+			}, "MsieChakraRT");
 			container.Register(new JavaScriptEngineFactory.Registration
 			{
-				Factory = () => new MsieJsEngine(new MsieConfiguration { EngineMode = JsEngineMode.Classic }),
+				Factory = () => new MsieJsEngine(new MsieConfiguration { EngineMode = JsEngineMode.ChakraActiveScript }),
 				Priority = 30
-			}, "MsieClassic");
+			}, "MsieChakraActiveScript");
 			container.Register(new JavaScriptEngineFactory.Registration
 			{
-				Factory = () => new JintJsEngine(),
-				Priority = 100
-			}, "Jint");
+				Factory = () => new MsieJsEngine(new MsieConfiguration { EngineMode = JsEngineMode.Classic }),
+				Priority = 40
+			}, "MsieClassic");
 		}
 	}
 }

src/React.JavaScriptEngine.ClearScriptV8/ClearScriptV8InitialisationException.cs renamed to src/React.Core/Exceptions/ClearScriptV8InitialisationException.cs

@@ -9,12 +9,11 @@
 
 using System;
 using System.Runtime.Serialization;
-using React.Exceptions;
 
-namespace React.JavaScriptEngine.ClearScriptV8
+namespace React.Exceptions
 {
 	/// <summary>
-	/// Thrown when the JavaScript engine does not support JSX transformation
+	/// Thrown when the ClearScript V8 JavaScript engine fails to initialise
 	/// </summary>
 	[Serializable]
 	public class ClearScriptV8InitialisationException : ReactException
@@ -38,8 +37,10 @@ private static string GetMessage(string innerMessage)
 		{
 			return
 				"Failed to initialise ClearScript V8. This is most likely caused by the native libraries " +
-				"(ClearScriptV8-64.dll and v8-x64.dll) missing from your app's Bin directory. Please " +
-				"ensure your app is referencing the JavaScriptEngineSwitcher.V8 NuGet package.\n\n" +
+				"(ClearScriptV8-64.dll and v8-x64.dll) missing from your app's Bin directory, or the " +
+				"Visual C++ runtime not being installed. Please ensure your app is referencing the " +
+				"JavaScriptEngineSwitcher.V8 NuGet package, and refer to the ReactJS.NET site for more" +
+				"debugging tips.\n\n" +
 				"More details: " + innerMessage;
 		}
 	}

src/React.Core/Exceptions/JsxUnsupportedEngineException.cs

@@ -0,0 +1,44 @@
+/*
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant 
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+using System;
+using System.Runtime.Serialization;
+
+namespace React.Exceptions
+{
+	/// <summary>
+	/// Thrown when no valid JavaScript engine is found.
+	/// </summary>
+	[Serializable]
+	public class ReactEngineNotFoundException : ReactException
+	{
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ReactEngineNotFoundException"/> class.
+		/// </summary>
+		public ReactEngineNotFoundException() : base(GetMessage()) { }
+
+		/// <summary>
+		/// Used by deserialization
+		/// </summary>
+		protected ReactEngineNotFoundException(SerializationInfo info, StreamingContext context)
+			: base(info, context) { }
+
+		/// <summary>
+		/// Gets a message that describes the current exception.
+		/// </summary>
+		private static string GetMessage()
+		{
+			return
+				"No usable JavaScript engine was found. Please install a JavaScript engine such " +
+				"as React.JavaScriptEngine.ClearScriptV8 (on Windows) or " +
+				"React.JavaScriptEngine.VroomJs (on Linux and Mac OS X). Refer to the ReactJS.NET " +
+				"documentation for more details.";
+		}
+	}
+}

src/React.Core/Exceptions/ReactEngineNotFoundException.cs

@@ -9,12 +9,11 @@
 
 using System;
 using System.Runtime.Serialization;
-using React.Exceptions;
 
-namespace React.JavaScriptEngine.VroomJs
+namespace React.Exceptions
 {
 	/// <summary>
-	/// Thrown when the JavaScript engine does not support JSX transformation
+	/// Thrown when the VroomJs V8 JavaScript engine fails to initialise.
 	/// </summary>
 	[Serializable]
 	public class VroomJsInitialisationException : ReactException
@@ -40,7 +39,8 @@ private static string GetMessage(string innerMessage)
 				"Failed to initialise VroomJs. This is most likely caused by the native library " +
 				"(libVroomJsNative.so) being out of date or your system lacking a compatible version of " +
 				"V8. Please run Mono with the `MONO_LOG_LEVEL=debug` environment variable for " +
-				"more debugging information. \n\n " +
+				"more debugging information, and refer to the ReactJS.NET Mono documentation at " +
+				"http://reactjs.net/guides/mono.html for further debugging hints.\n\n " +
 				"More details: " + innerMessage;
 		}
 	}

src/React.JavaScriptEngine.VroomJs/VroomJsInitialisationException.cs renamed to src/React.Core/Exceptions/VroomJsInitialisationException.cs

@@ -6,6 +6,7 @@
 using System.Linq;
 using System.Threading;
 using JavaScriptEngineSwitcher.Core;
+using JavaScriptEngineSwitcher.V8;
 using JSPool;
 using React.Exceptions;
 
@@ -133,12 +134,7 @@ protected virtual void InitialiseEngine(IJsEngine engine)
 			engine.ExecuteResource("React.Resources.shims.js", thisAssembly);
 			engine.ExecuteResource("React.Resources.react-with-addons.js", thisAssembly);
 			engine.Execute("var React = global.React");
-
-			// Only load JSX Transformer if engine supports it
-			if (engine.SupportsJsxTransformer())
-			{
-				engine.ExecuteResource("React.Resources.JSXTransformer.js", thisAssembly);
-			}
+			engine.ExecuteResource("React.Resources.JSXTransformer.js", thisAssembly);
 		}
 
 		/// <summary>
@@ -234,7 +230,20 @@ private static Func<IJsEngine> GetFactory(IEnumerable<Registration> availableFac
 			}
 
 			// Epic fail, none of the engines worked. Nothing we can do now.
-			throw new ReactException("No usable JavaScript engine found :(");
+			// Throw an error relevant to the engine they should be able to use.
+			if (JavaScriptEngineUtils.EnvironmentSupportsClearScript())
+			{
+				JavaScriptEngineUtils.EnsureEngineFunctional<V8JsEngine, ClearScriptV8InitialisationException>(
+					ex => new ClearScriptV8InitialisationException(ex.Message)
+				);
+			}
+			else if (JavaScriptEngineUtils.EnvironmentSupportsVroomJs())
+			{
+				JavaScriptEngineUtils.EnsureEngineFunctional<VroomJsEngine, VroomJsInitialisationException>(
+					ex => new VroomJsInitialisationException(ex.Message)
+				);
+			}
+			throw new ReactEngineNotFoundException();
 		}
 
 		/// <summary>

src/React.Core/JavaScriptEngineExtensions.cs

@@ -0,0 +1,67 @@
+/*
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant 
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+using System;
+using JavaScriptEngineSwitcher.Core;
+using React.Exceptions;
+
+namespace React
+{
+	/// <summary>
+	/// Various helper methods for the JavaScript engine environment.
+	/// </summary>
+	public static class JavaScriptEngineUtils
+	{
+		/// <summary>
+		/// Determines if the current environment supports the VroomJs engine.
+		/// </summary>
+		/// <returns><c>true</c> if VroomJs is supported</returns>
+		public static bool EnvironmentSupportsVroomJs()
+		{
+			return Environment.OSVersion.Platform == PlatformID.Unix;
+		}
+
+		/// <summary>
+		/// Determines if the current environment supports the ClearScript V8 engine
+		/// </summary>
+		/// <returns><c>true</c> if ClearScript is supported</returns>
+		public static bool EnvironmentSupportsClearScript()
+		{
+			return Environment.OSVersion.Platform == PlatformID.Win32NT;
+		}
+
+		/// <summary>
+		/// Attempts to use the specified engine and throws an exception if it doesn't work.
+		/// </summary>
+		public static void EnsureEngineFunctional<TEngine, TException>(
+			Func<Exception, TException> exceptionFactory
+		) 
+			where TEngine : IJsEngine, new()
+			where TException : Exception
+		{
+			int result;
+			try
+			{
+				using (var engine = new TEngine())
+				{
+					result = engine.Evaluate<int>("1 + 1");
+				}
+			}
+			catch (Exception ex)
+			{
+				throw exceptionFactory(ex);
+			}
+
+			if (result != 2)
+			{
+				throw new ReactException("Mathematics is broken. 1 + 1 = " + result);
+			}
+		}
+	}
+}