/// <summary>
/// Attempts to execute the provided JavaScript code using a non-pooled JavaScript engine (ie.
/// creates a new JS engine per-thread). This is because Babel uses a LOT of memory, so we
/// should completely dispose any engines that have loaded Babel in order to conserve memory.
///
/// If an exception is thrown, retries the execution using a new thread (and hence a new engine)
/// with a larger maximum stack size.
/// This is required because JSXTransformer uses a huge stack which ends up being larger
/// than what ASP.NET allows by default (256 KB).
/// </summary>
/// <typeparam name="T">Type to return from JavaScript call</typeparam>
/// <param name="function">JavaScript function to execute</param>
/// <param name="args">Arguments to pass to function</param>
/// <returns>Result returned from JavaScript code</returns>
public virtual T ExecuteWithBabel <T>(string function, params object[] args)
{
var engine = _engineFactory.GetEngineForCurrentThread();
EnsureBabelLoaded(engine);
#if NET40 || NET45 || NETSTANDARD2_0
try
{
return(engine.CallFunctionReturningJson <T>(function, args));
}
catch (Exception)
{
// Assume the exception MAY be an "out of stack space" error. Try running the code
// in a different thread with larger stack. If the same exception occurs, we know
// it wasn't a stack space issue.
T result = default(T);
Exception innerEx = null;
var thread = new Thread(() =>
{
// New engine will be created here (as this is a new thread)
var threadEngine = _engineFactory.GetEngineForCurrentThread();
EnsureBabelLoaded(threadEngine);
try
{
result = threadEngine.CallFunctionReturningJson <T>(function, args);
}
catch (Exception threadEx)
{
// Unhandled exceptions in threads kill the whole process.
// Pass the exception back to the parent thread to rethrow.
innerEx = threadEx;
}
finally
{
_engineFactory.DisposeEngineForCurrentThread();
}
}, LARGE_STACK_SIZE);
thread.Start();
thread.Join();
// Rethrow any exceptions that occured in the thread
if (innerEx != null)
{
throw innerEx;
}
return(result);
}
#else
return(engine.CallFunctionReturningJson <T>(function, args));
#endif
}
/// <summary>
/// Attempts to execute the provided JavaScript code using the current engine. If an
/// exception is thrown, retries the execution using a new thread (and hence a new engine)
/// with a larger maximum stack size.
/// This is required because JSXTransformer uses a huge stack which ends up being larger
/// than what ASP.NET allows by default (256 KB).
/// </summary>
/// <typeparam name="T">Type to return from JavaScript call</typeparam>
/// <param name="function">JavaScript function to execute</param>
/// <param name="args">Arguments to pass to function</param>
/// <returns>Result returned from JavaScript code</returns>
public virtual T ExecuteWithLargerStackIfRequired <T>(string function, params object[] args)
{
// This hack is not required when pooling JavaScript engines, since pooled MSIE
// engines already execute on their own thread with a larger stack.
if (_config.ReuseJavaScriptEngines)
{
return(Execute <T>(function, args));
}
try
{
return(Execute <T>(function, args));
}
catch (Exception)
{
// Assume the exception MAY be an "out of stack space" error. Try running the code
// in a different thread with larger stack. If the same exception occurs, we know
// it wasn't a stack space issue.
T result = default(T);
Exception innerEx = null;
var thread = new Thread(() =>
{
// New engine will be created here (as this is a new thread)
var engine = _engineFactory.GetEngineForCurrentThread();
try
{
result = engine.CallFunction <T>(function, args);
}
catch (Exception threadEx)
{
// Unhandled exceptions in threads kill the whole process.
// Pass the exception back to the parent thread to rethrow.
innerEx = threadEx;
}
finally
{
_engineFactory.DisposeEngineForCurrentThread();
}
}, LARGE_STACK_SIZE);
thread.Start();
thread.Join();
// Rethrow any exceptions that occured in the thread
if (innerEx != null)
{
throw innerEx;
}
return(result);
}
}