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namespace System.Web.Mvc.Async {
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
public class AsyncControllerActionInvoker : ControllerActionInvoker, IAsyncActionInvoker {
private static readonly object _invokeActionTag = new object();
private static readonly object _invokeActionMethodTag = new object();
private static readonly object _invokeActionMethodWithFiltersTag = new object();
public virtual IAsyncResult BeginInvokeAction(ControllerContext controllerContext, string actionName, AsyncCallback callback, object state) {
if (controllerContext == null) {
throw new ArgumentNullException("controllerContext");
}
if (String.IsNullOrEmpty(actionName)) {
throw Error.ParameterCannotBeNullOrEmpty("actionName");
}
ControllerDescriptor controllerDescriptor = GetControllerDescriptor(controllerContext);
ActionDescriptor actionDescriptor = controllerDescriptor.FindAction(controllerContext, actionName);
if (actionDescriptor != null) {
FilterInfo filterInfo = GetFilters(controllerContext, actionDescriptor);
Action continuation = null;
BeginInvokeDelegate beginDelegate = delegate(AsyncCallback asyncCallback, object asyncState) {
try {
AuthorizationContext authContext = InvokeAuthorizationFilters(controllerContext, filterInfo.AuthorizationFilters, actionDescriptor);
if (authContext.Result != null) {
// the auth filter signaled that we should let it short-circuit the request
continuation = () => InvokeActionResult(controllerContext, authContext.Result);
}
else {
if (controllerContext.Controller.ValidateRequest) {
ValidateRequest(controllerContext);
}
IDictionary<string, object> parameters = GetParameterValues(controllerContext, actionDescriptor);
IAsyncResult asyncResult = BeginInvokeActionMethodWithFilters(controllerContext, filterInfo.ActionFilters, actionDescriptor, parameters, asyncCallback, asyncState);
continuation = () => {
ActionExecutedContext postActionContext = EndInvokeActionMethodWithFilters(asyncResult);
InvokeActionResultWithFilters(controllerContext, filterInfo.ResultFilters, postActionContext.Result);
};
return asyncResult;
}
}
catch (ThreadAbortException) {
// This type of exception occurs as a result of Response.Redirect(), but we special-case so that
// the filters don't see this as an error.
throw;
}
catch (Exception ex) {
// something blew up, so execute the exception filters
ExceptionContext exceptionContext = InvokeExceptionFilters(controllerContext, filterInfo.ExceptionFilters, ex);
if (!exceptionContext.ExceptionHandled) {
throw;
}
continuation = () => InvokeActionResult(controllerContext, exceptionContext.Result);
}
return BeginInvokeAction_MakeSynchronousAsyncResult(asyncCallback, asyncState);
};
EndInvokeDelegate<bool> endDelegate = delegate(IAsyncResult asyncResult) {
try {
continuation();
}
catch (ThreadAbortException) {
// This type of exception occurs as a result of Response.Redirect(), but we special-case so that
// the filters don't see this as an error.
throw;
}
catch (Exception ex) {
// something blew up, so execute the exception filters
ExceptionContext exceptionContext = InvokeExceptionFilters(controllerContext, filterInfo.ExceptionFilters, ex);
if (!exceptionContext.ExceptionHandled) {
throw;
}
InvokeActionResult(controllerContext, exceptionContext.Result);
}
return true;
};
return AsyncResultWrapper.Begin(callback, state, beginDelegate, endDelegate, _invokeActionTag);
}
else {
// Notify the controller that no action was found.
return BeginInvokeAction_ActionNotFound(callback, state);
}
}
private static IAsyncResult BeginInvokeAction_ActionNotFound(AsyncCallback callback, object state) {
BeginInvokeDelegate beginDelegate = BeginInvokeAction_MakeSynchronousAsyncResult;
EndInvokeDelegate<bool> endDelegate = delegate(IAsyncResult asyncResult) {
return false;
};
return AsyncResultWrapper.Begin(callback, state, beginDelegate, endDelegate, _invokeActionTag);
}
private static IAsyncResult BeginInvokeAction_MakeSynchronousAsyncResult(AsyncCallback callback, object state) {
SimpleAsyncResult asyncResult = new SimpleAsyncResult(state);
asyncResult.MarkCompleted(true /* completedSynchronously */, callback);
return asyncResult;
}
protected internal virtual IAsyncResult BeginInvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters, AsyncCallback callback, object state) {
AsyncActionDescriptor asyncActionDescriptor = actionDescriptor as AsyncActionDescriptor;
if (asyncActionDescriptor != null) {
return BeginInvokeAsynchronousActionMethod(controllerContext, asyncActionDescriptor, parameters, callback, state);
}
else {
return BeginInvokeSynchronousActionMethod(controllerContext, actionDescriptor, parameters, callback, state);
}
}
protected internal virtual IAsyncResult BeginInvokeActionMethodWithFilters(ControllerContext controllerContext, IList<IActionFilter> filters, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters, AsyncCallback callback, object state) {
Func<ActionExecutedContext> endContinuation = null;
BeginInvokeDelegate beginDelegate = delegate(AsyncCallback asyncCallback, object asyncState) {
ActionExecutingContext preContext = new ActionExecutingContext(controllerContext, actionDescriptor, parameters);
IAsyncResult innerAsyncResult = null;
Func<Func<ActionExecutedContext>> beginContinuation = () => {
innerAsyncResult = BeginInvokeActionMethod(controllerContext, actionDescriptor, parameters, asyncCallback, asyncState);
return () =>
new ActionExecutedContext(controllerContext, actionDescriptor, false /* canceled */, null /* exception */) {
Result = EndInvokeActionMethod(innerAsyncResult)
};
};
// need to reverse the filter list because the continuations are built up backward
Func<Func<ActionExecutedContext>> thunk = filters.Reverse().Aggregate(beginContinuation,
(next, filter) => () => InvokeActionMethodFilterAsynchronously(filter, preContext, next));
endContinuation = thunk();
if (innerAsyncResult != null) {
// we're just waiting for the inner result to complete
return innerAsyncResult;
}
else {
// something was short-circuited and the action was not called, so this was a synchronous operation
SimpleAsyncResult newAsyncResult = new SimpleAsyncResult(asyncState);
newAsyncResult.MarkCompleted(true /* completedSynchronously */, asyncCallback);
return newAsyncResult;
}
};
EndInvokeDelegate<ActionExecutedContext> endDelegate = delegate(IAsyncResult asyncResult) {
return endContinuation();
};
return AsyncResultWrapper.Begin(callback, state, beginDelegate, endDelegate, _invokeActionMethodWithFiltersTag);
}
private IAsyncResult BeginInvokeAsynchronousActionMethod(ControllerContext controllerContext, AsyncActionDescriptor actionDescriptor, IDictionary<string, object> parameters, AsyncCallback callback, object state) {
BeginInvokeDelegate beginDelegate = delegate(AsyncCallback asyncCallback, object asyncState) {
return actionDescriptor.BeginExecute(controllerContext, parameters, asyncCallback, asyncState);
};
EndInvokeDelegate<ActionResult> endDelegate = delegate(IAsyncResult asyncResult) {
object returnValue = actionDescriptor.EndExecute(asyncResult);
ActionResult result = CreateActionResult(controllerContext, actionDescriptor, returnValue);
return result;
};
return AsyncResultWrapper.Begin(callback, state, beginDelegate, endDelegate, _invokeActionMethodTag);
}
private IAsyncResult BeginInvokeSynchronousActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters, AsyncCallback callback, object state) {
return AsyncResultWrapper.BeginSynchronous(callback, state,
() => InvokeSynchronousActionMethod(controllerContext, actionDescriptor, parameters),
_invokeActionMethodTag);
}
public virtual bool EndInvokeAction(IAsyncResult asyncResult) {
return AsyncResultWrapper.End<bool>(asyncResult, _invokeActionTag);
}
protected internal virtual ActionResult EndInvokeActionMethod(IAsyncResult asyncResult) {
return AsyncResultWrapper.End<ActionResult>(asyncResult, _invokeActionMethodTag);
}
protected internal virtual ActionExecutedContext EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) {
return AsyncResultWrapper.End<ActionExecutedContext>(asyncResult, _invokeActionMethodWithFiltersTag);
}
protected override ControllerDescriptor GetControllerDescriptor(ControllerContext controllerContext) {
Type controllerType = controllerContext.Controller.GetType();
ControllerDescriptor controllerDescriptor = DescriptorCache.GetDescriptor(controllerType, () => new ReflectedAsyncControllerDescriptor(controllerType));
return controllerDescriptor;
}
internal static Func<ActionExecutedContext> InvokeActionMethodFilterAsynchronously(IActionFilter filter, ActionExecutingContext preContext, Func<Func<ActionExecutedContext>> nextInChain) {
filter.OnActionExecuting(preContext);
if (preContext.Result != null) {
ActionExecutedContext shortCircuitedPostContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, true /* canceled */, null /* exception */) {
Result = preContext.Result
};
return () => shortCircuitedPostContext;
}
// There is a nested try / catch block here that contains much the same logic as the outer block.
// Since an exception can occur on either side of the asynchronous invocation, we need guards on
// on both sides. In the code below, the second side is represented by the nested delegate. This
// is really just a parallel of the synchronous ControllerActionInvoker.InvokeActionMethodFilter()
// method.
try {
Func<ActionExecutedContext> continuation = nextInChain();
// add our own continuation, then return the new function
return () => {
ActionExecutedContext postContext;
bool wasError = true;
try {
postContext = continuation();
wasError = false;
}
catch (ThreadAbortException) {
// This type of exception occurs as a result of Response.Redirect(), but we special-case so that
// the filters don't see this as an error.
postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, null /* exception */);
filter.OnActionExecuted(postContext);
throw;
}
catch (Exception ex) {
postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, ex);
filter.OnActionExecuted(postContext);
if (!postContext.ExceptionHandled) {
throw;
}
}
if (!wasError) {
filter.OnActionExecuted(postContext);
}
return postContext;
};
}
catch (ThreadAbortException) {
// This type of exception occurs as a result of Response.Redirect(), but we special-case so that
// the filters don't see this as an error.
ActionExecutedContext postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, null /* exception */);
filter.OnActionExecuted(postContext);
throw;
}
catch (Exception ex) {
ActionExecutedContext postContext = new ActionExecutedContext(preContext, preContext.ActionDescriptor, false /* canceled */, ex);
filter.OnActionExecuted(postContext);
if (postContext.ExceptionHandled) {
return () => postContext;
}
else {
throw;
}
}
}
private ActionResult InvokeSynchronousActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters) {
return base.InvokeActionMethod(controllerContext, actionDescriptor, parameters);
}
}
}
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