public void Undo()
{
if (thread == null)
{
return; // Don't do anything
}
if (thread != Thread.CurrentThread)
{
throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_CannotUseSwitcherOtherThread"));
}
if ( currEC != Thread.CurrentThread.GetExecutionContextNoCreate())
{
throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_SwitcherCtxMismatch"));
}
BCLDebug.Assert(currEC != null, " ExecutionContext can't be null");
// Any critical failure inside scsw will cause FailFast
scsw.Undo();
try
{
HostExecutionContextSwitcher.Undo(hecsw);
}
finally
{
// Even if HostExecutionContextSwitcher.Undo(hecsw) throws, we need to revert
// synchronizationContext. If that throws, we'll be throwing an ex during an exception
// unwind. That's OK - we'll just have nested exceptions.
sysw.Undo();
}
// restore the saved Execution Context
Thread.CurrentThread.SetExecutionContext(prevEC);
thread = null; // this will prevent the switcher object being used again
}
} public static void Run(ExecutionContext executionContext, ContextCallback callback, Object state)
{
if (executionContext == null)
{
throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_NullContext"));
}
Thread currentThread = Thread.CurrentThread;
ExecutionContextSwitcher ecsw = default(ExecutionContextSwitcher);
try
{
EstablishCopyOnWriteScope(currentThread, ref ecsw);
ExecutionContext.Restore(currentThread, executionContext);
callback(state);
}
catch
{
// Note: we have a "catch" rather than a "finally" because we want
// to stop the first pass of EH here. That way we can restore the previous
// context before any of our callers' EH filters run. That means we need to
// end the scope separately in the non-exceptional case below.
ecsw.Undo(currentThread);
throw;
}
ecsw.Undo(currentThread);
}
