public void ValidateReentrancyPreventsReentrancyWithFuncVariant()
{
var reentrancyGuard = new ReentrancyGuard();
bool isInGuard = false;
bool executedGuardedCode = false;
using (ManualResetEvent nonReentrantCode = new ManualResetEvent(false))
using (ManualResetEvent nonReentrantCodeDone = new ManualResetEvent(false))
{
reentrancyGuard.IsReentrancyPrevented.Should().BeFalse();
var allowedThread = new Thread(() =>
{
ReentrancyGuard.CallReentrancySafe(reentrancyGuard, () =>
{
nonReentrantCode.Set();
isInGuard = true;
nonReentrantCodeDone.WaitOne();
isInGuard = false;
executedGuardedCode = true;
return(executedGuardedCode);
}).Should().Be(ReentrancyGuard.ReentrancyCallResult.Success);
executedGuardedCode.ShouldBeEquivalentTo(true);
});
allowedThread.Start();
nonReentrantCode.WaitOne(TimeSpan.FromSeconds(1)).Should().BeTrue();
for (int i = 0; i < 1000; i++)
{
reentrancyGuard.IsReentrancyPrevented.Should().BeTrue();
ReentrancyGuard.CallReentrancySafe(reentrancyGuard, () =>
{
throw new Exception("Reentered method despite guard being present");
#pragma warning disable 162
return(true);
#pragma warning restore 162
}).ShouldBeEquivalentTo(ReentrancyGuard.ReentrancyCallResult.GuardBlocked);
}
nonReentrantCodeDone.Set();
allowedThread.Join();
reentrancyGuard.IsReentrancyPrevented.ShouldBeEquivalentTo(false);
executedGuardedCode.ShouldBeEquivalentTo(true);
}
}
public CommandState GetCommandState <T>(Func <ITextView, ITextBuffer, T> argsFactory, Func <CommandState> nextCommandHandler) where T : EditorCommandArgs
{
if (!_factory.JoinableTaskContext.IsOnMainThread)
{
throw new InvalidOperationException($"{nameof(IEditorCommandHandlerService.GetCommandState)} method shoudl only be called on the UI thread.");
}
// In Razor scenario it's possible that EditorCommandHandlerService is called re-entrantly,
// first by contained language command filter and then by editor command chain.
// To preserve Razor commanding semantics, only execute handlers once.
if (IsReentrantCall())
{
return(nextCommandHandler?.Invoke() ?? CommandState.Unavailable);
}
using (var reentrancyGuard = new ReentrancyGuard(_textView))
{
// Build up chain of handlers per buffer
Func <CommandState> handlerChain = nextCommandHandler ?? UnavalableCommandFunc;
foreach (var bufferAndHandler in GetOrderedBuffersAndCommandHandlers <T>().Reverse())
{
T args = null;
// Declare locals to ensure that we don't end up capturing the wrong thing
var nextHandler = handlerChain;
var handler = bufferAndHandler.handler;
args = args ?? (args = argsFactory(_textView, bufferAndHandler.buffer));
if (args == null)
{
// Args factory failed, skip command handlers and just call next
return(handlerChain());
}
handlerChain = () => handler.GetCommandState(args, nextHandler);
}
// Kick off the first command handler
return(handlerChain());
}
}
public void Execute <T>(Func <ITextView, ITextBuffer, T> argsFactory, Action nextCommandHandler) where T : EditorCommandArgs
{
if (!_factory.JoinableTaskContext.IsOnMainThread)
{
throw new InvalidOperationException($"{nameof(IEditorCommandHandlerService.Execute)} method should only be called on the UI thread.");
}
// In contained languge (Razor) scenario it's possible that EditorCommandHandlerService is called re-entrantly
// for the same command, first by contained language command filter and then by editor command chain.
// To preserve Razor commanding semantics, only execute handlers once for the same command.
if (IsReentrantCall <T>())
{
nextCommandHandler?.Invoke();
return;
}
EditorCommandHandlerServiceState state = null;
using (var reentrancyGuard = new ReentrancyGuard <T>(_textView))
{
// Build up chain of handlers per buffer
Action handlerChain = nextCommandHandler ?? EmptyAction;
// TODO: realize the chain dynamically and without Reverse()
foreach (var bufferAndHandler in GetOrderedBuffersAndCommandHandlers <T>().Reverse())
{
T args = null;
// Declare locals to ensure that we don't end up capturing the wrong thing
var nextHandler = handlerChain;
var handler = bufferAndHandler.handler;
args = args ?? (args = argsFactory(_textView, bufferAndHandler.buffer));
if (args == null)
{
// Args factory failed, skip command handlers and just call next
handlerChain();
return;
}
if (handler is IDynamicCommandHandler <T> dynamicCommandHandler &&
!dynamicCommandHandler.CanExecuteCommand(args))
{
// Skip this one as it cannot execute the command.
continue;
}
if (state == null)
{
state = InitializeExecutionState(args);
}
handlerChain = () => _factory.GuardedOperations.CallExtensionPoint(handler,
() =>
{
state.OnExecutingCommandHandlerBegin(handler);
handler.ExecuteCommand(args, nextHandler, state.ExecutionContext);
state.OnExecutingCommandHandlerEnd(handler);
},
// Do not guard against cancellation exceptions, they are handled by ExecuteCommandHandlerChain
exceptionGuardFilter: (e) => !IsOperationCancelledException(e));
}
if (state == null)
{
// No matching command handlers, just call next
handlerChain();
return;
}
_telemetrySession?.BeforeKeyProcessed();
ExecuteCommandHandlerChain(state, handlerChain, nextCommandHandler);
_telemetrySession?.AfterKeyProcessed();
}
}
private bool IsReentrantCall <T>() where T : EditorCommandArgs
{
return(ReentrancyGuard <T> .IsReentrantCall(_textView));
}
