internal class NtSignalState : PythonSignalState {

//We use a single Windows event handler to process all signals. This handler simply

//delegates the work out to PySignalToPyHandler.

public NativeSignal.WinSignalsHandler WinAllSignalsHandlerDelegate;

public NtSignalState(PythonContext pc) : base(pc) {

WinAllSignalsHandlerDelegate = new NativeSignal.WinSignalsHandler(WindowsEventHandler);

NativeSignal.SetConsoleCtrlHandler(this.WinAllSignalsHandlerDelegate, true);

}

//Our implementation of WinSignalsHandler

private bool WindowsEventHandler(uint winSignal) {

bool retVal;

int pySignal;

switch (winSignal) {

case CTRL_C_EVENT:

pySignal = SIGINT;

break;

case CTRL_BREAK_EVENT:

pySignal = SIGBREAK;

break;

case CTRL_CLOSE_EVENT:

pySignal = SIGBREAK;

break;

case CTRL_LOGOFF_EVENT:

pySignal = SIGBREAK;

break;

case CTRL_SHUTDOWN_EVENT:

pySignal = SIGBREAK;

break;

default:

throw new Exception("unreachable");

}

lock (PySignalToPyHandler) {

if (PySignalToPyHandler[pySignal].GetType() == typeof(int)) {

int tempId = (int)PySignalToPyHandler[pySignal];

if (tempId == SIG_DFL) {

//SIG_DFL - we let Windows do whatever it normally would

retVal = false;

} else if (tempId == SIG_IGN) {

//SIG_IGN - we do nothing, but tell Windows we handled the signal

retVal = true;

} else {

throw new Exception("unreachable");

}

} else if (PySignalToPyHandler[pySignal] == default_int_handler) {

if (pySignal != SIGINT) {

//We're dealing with the default_int_handlerImpl which we

//know doesn't care about the frame parameter

retVal = true;

default_int_handlerImpl(pySignal, null);

} else {

//Let the real interrupt handler throw a KeyboardInterrupt for SIGINT.

//It handles this far more gracefully than we can

retVal = false;

}

} else {

//We're dealing with a callable matching PySignalHandler's signature

retVal = true;

PySignalHandler temp = (PySignalHandler)Converter.ConvertToDelegate(PySignalToPyHandler[pySignal],

typeof(PySignalHandler));

try {

if (SignalPythonContext.PythonOptions.Frames) {

temp.Invoke(pySignal, SysModule._getframeImpl(null,

0,

SignalPythonContext._mainThreadFunctionStack));

} else {

temp.Invoke(pySignal, null);

}

} catch (Exception e) {

System.Console.WriteLine(SignalPythonContext.FormatException(e));

}

}

}

return retVal;

}

}

internal static class NativeSignal {

// Windows API expects to be given a function pointer like this to handle signals

internal delegate bool WinSignalsHandler(uint winSignal);

[DllImport("Kernel32")]

[return: MarshalAs(UnmanagedType.Bool)]

internal static extern bool SetConsoleCtrlHandler(WinSignalsHandler Handler, [MarshalAs(UnmanagedType.Bool)]bool Add);

[DllImport("Kernel32")]

[return: MarshalAs(UnmanagedType.Bool)]

internal static extern bool GenerateConsoleCtrlEvent(uint dwCtrlEvent, uint dwProcessGroupId);

}