/// <summary>
/// Gets a factory for the most appropriate JavaScript engine for the current environment.
/// The first functioning JavaScript engine with the lowest priority will be used.
/// </summary>
/// <returns>Function to create JavaScript engine</returns>
private static Func <IJsEngine> GetFactory(IEnumerable <Registration> availableFactories)
{
var availableEngineFactories = availableFactories
.OrderBy(x => x.Priority)
.Select(x => x.Factory);
foreach (var engineFactory in availableEngineFactories)
{
IJsEngine engine = null;
try
{
engine = engineFactory();
// Perform a sanity test to ensure this engine is usable
if (engine.Evaluate <int>("1 + 1") == 2)
{
// Success! Use this one.
return(engineFactory);
}
}
catch (Exception ex)
{
// This engine threw an exception, try the next one
Trace.WriteLine(string.Format("Error initialising {0}: {1}", engineFactory, ex));
}
finally
{
if (engine != null)
{
engine.Dispose();
}
}
}
// Epic fail, none of the engines worked. Nothing we can do now.
// 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>
/// Gets a factory for the most appropriate JavaScript engine for the current environment.
/// The first functioning JavaScript engine with the lowest priority will be used.
/// </summary>
/// <returns>Function to create JavaScript engine</returns>
private static Func <IJsEngine> GetFactory(JsEngineSwitcher jsEngineSwitcher, bool allowMsie)
{
EnsureJsEnginesRegistered(jsEngineSwitcher, allowMsie);
foreach (var engineFactory in jsEngineSwitcher.EngineFactories)
{
IJsEngine engine = null;
try
{
engine = engineFactory.CreateEngine();
if (EngineIsUsable(engine, allowMsie))
{
// Success! Use this one.
return(engineFactory.CreateEngine);
}
}
catch (Exception ex)
{
// This engine threw an exception, try the next one
Trace.WriteLine(string.Format("Error initialising {0}: {1}", engineFactory, ex));
}
finally
{
if (engine != null)
{
engine.Dispose();
}
}
}
// Epic fail, none of the engines worked. Nothing we can do now.
// Throw an error relevant to the engine they should be able to use.
#if NET40
if (JavaScriptEngineUtils.EnvironmentSupportsClearScript())
{
JavaScriptEngineUtils.EnsureEngineFunctional <V8JsEngine, ClearScriptV8InitialisationException>(
ex => new ClearScriptV8InitialisationException(ex)
);
}
#endif
#if NET40 || NETSTANDARD1_6
if (JavaScriptEngineUtils.EnvironmentSupportsVroomJs())
{
JavaScriptEngineUtils.EnsureEngineFunctional <VroomJsEngine, VroomJsInitialisationException>(
ex => new VroomJsInitialisationException(ex.Message)
);
}
#endif
throw new ReactEngineNotFoundException();
}
/// <summary>
/// Gets a factory for the most appropriate JavaScript engine for the current environment.
/// The first functioning JavaScript engine with the lowest priority will be used.
/// </summary>
/// <returns>Function to create JavaScript engine</returns>
private static Func <IJsEngine> GetFactory(IJsEngineSwitcher jsEngineSwitcher, bool allowMsie)
{
EnsureJsEnginesRegistered(jsEngineSwitcher, allowMsie);
string defaultEngineName = jsEngineSwitcher.DefaultEngineName;
if (!string.IsNullOrWhiteSpace(defaultEngineName))
{
var engineFactory = jsEngineSwitcher.EngineFactories.Get(defaultEngineName);
if (engineFactory != null)
{
return(engineFactory.CreateEngine);
}
else
{
throw new ReactEngineNotFoundException(
"Could not find a factory that creates an instance of the JavaScript " +
"engine with name `" + defaultEngineName + "`.");
}
}
foreach (var engineFactory in jsEngineSwitcher.EngineFactories)
{
IJsEngine engine = null;
try
{
engine = engineFactory.CreateEngine();
if (EngineIsUsable(engine, allowMsie))
{
// Success! Use this one.
return(engineFactory.CreateEngine);
}
}
catch (Exception ex)
{
// This engine threw an exception, try the next one
Trace.WriteLine(string.Format("Error initialising {0}: {1}", engineFactory, ex));
}
finally
{
if (engine != null)
{
engine.Dispose();
}
}
}
// Epic fail, none of the engines worked. Nothing we can do now.
// Throw an error relevant to the engine they should be able to use.
#if NET45
if (JavaScriptEngineUtils.EnvironmentSupportsClearScript())
{
JavaScriptEngineUtils.EnsureEngineFunctional <V8JsEngine, ClearScriptV8InitialisationException>(
ex => new ClearScriptV8InitialisationException(ex)
);
}
#endif
if (JavaScriptEngineUtils.EnvironmentSupportsVroomJs())
{
JavaScriptEngineUtils.EnsureEngineFunctional <VroomJsEngine, VroomJsInitialisationException>(
ex => new VroomJsInitialisationException(ex.Message)
);
}
throw new ReactEngineNotFoundException();
}
