freeswitch/src/mod/languages/mod_python/freeswitch_python.cpp

#include "freeswitch_python.h"

#define sanity_check(x) do { if (!session) { switch_log_printf(SWITCH_CHANNEL_LOG,SWITCH_LOG_ERROR, "session is not initalized\n"); return x;}} while(0)
#define init_vars() do { caller_profile.source = "mod_python"; swapstate = S_SWAPPED_IN; } while(0)

PySession::PySession():CoreSession()
{
	init_vars();
}

PySession::PySession(char *uuid):CoreSession(uuid)
{
	init_vars();
}

PySession::PySession(switch_core_session_t *new_session):CoreSession(new_session)
{
	init_vars();
}


void PySession::setDTMFCallback(PyObject * pyfunc, char *funcargs)
{
	sanity_check();

	if (!PyCallable_Check(pyfunc)) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "DTMF function is not a python function.\n");
		return;
	}
	Py_XINCREF(pyfunc);
	CoreSession::setDTMFCallback((void *) pyfunc, funcargs);


}

void PySession::setHangupHook(PyObject * pyfunc)
{

	if (!PyCallable_Check(pyfunc)) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "Hangup hook is not a python function.\n");
		return;
	}
	// without this Py_XINCREF, there will be segfaults.  basically the python
	// interpreter will not know that it should not GC this object.
	// callback example: http://docs.python.org/ext/callingPython.html
	Py_XINCREF(pyfunc);
	CoreSession::setHangupHook((void *) pyfunc);

}


void PySession::check_hangup_hook()
{
	PyObject *func;
	PyObject *result;
	char *resultStr;
	bool did_swap_in = false;

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING,
					  "check_hangup_hook has been DISABLED, please do not use hangup hooks in python code until further notice!\n");

	if (!session) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "No valid session\n");
		return;
	}

	return;

	/*! NEEDS TO BE FIXED:

	   // The did_swap_in boolean was added to fix the following problem:
	   // Design flaw - we swap in threadstate based on the assumption that thread state 
	   // is currently _swapped out_ when this hangup hook is called.  However, nothing known to 
	   // guarantee that, and  if thread state is already swapped in when this is invoked, 
	   // bad things will happen.
	   switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "check hangup hook end_allow_threads\n");
	   did_swap_in = end_allow_threads();

	   if (on_hangup == NULL) {
	   switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "on_hangup is null\n");
	   return;
	   }

	   func = (PyObject *) on_hangup;

	   // TODO: to match js implementation, should pass the _python_ PySession 
	   // object instance wrapping this C++ PySession instance. but how do we do that?
	   // for now, pass the uuid since its better than nothing
	   PyObject* func_arg = Py_BuildValue("(s)", uuid);

	   result = PyEval_CallObject(func, func_arg);
	   Py_XDECREF(func_arg);

	   if (result) {
	   resultStr = (char *) PyString_AsString(result);
	   // currently just ignore the result
	   }
	   else {
	   switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Failed to call python hangup callback\n");
	   PyErr_Print();
	   PyErr_Clear();
	   }

	   switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "check hangup hook begin_allow_threads\n");
	   if (did_swap_in) {
	   begin_allow_threads();
	   }

	   Py_XDECREF(result);
	 */
}

switch_status_t PySession::run_dtmf_callback(void *input, switch_input_type_t itype)
{

	PyObject *func, *arglist;
	PyObject *pyresult;
	PyObject *headerdict;

	char *resultStr;
	char *funcargs;
	switch_file_handle_t *fh = NULL;
	bool did_swap_in = false;

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "run_dtmf_callback\n");


	if (!cb_state.function) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "cb_state->function is null\n");
		return SWITCH_STATUS_FALSE;
	}

	func = (PyObject *) cb_state.function;
	if (!func) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "cb_state->function is null\n");
		return SWITCH_STATUS_FALSE;
	} else {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "cb_state->function is NOT null\n");
	}
	if (!PyCallable_Check(func)) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "function not callable\n");
		return SWITCH_STATUS_FALSE;
	}

	funcargs = (char *) cb_state.funcargs;

	if (itype == SWITCH_INPUT_TYPE_DTMF) {

		arglist = Py_BuildValue("(sis)", input, itype, funcargs);
	} else if (itype == SWITCH_INPUT_TYPE_EVENT) {
		// DUNNO if this is correct in the case we have an event
		// will be of type switch_event_t *event;
		// http://www.freeswitch.org/docs/structswitch__event.html
		switch_event_t *event = (switch_event_t *) input;
		arglist = Py_BuildValue("({s:s}is)", "body", event->body, itype, funcargs);

		// build a dictionary with all the headers

		switch_event_header_t *hp;
		headerdict = PyDict_New();
		for (hp = event->headers; hp; hp = hp->next) {
			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "Adding event header to result");

			// TODO: create PyObject pointers for name and value
			// and explicitly decref them.  all ref counting stuff is 
			// a mess and needs to be tested and looked at closer.
			PyDict_SetItem(headerdict, Py_BuildValue("s", hp->name), Py_BuildValue("s", hp->value));

		}

		// add it to the main event dictionary (first arg in list)
		// under key 'headers'
		PyObject *dict = PyTuple_GetItem(arglist, 0);
		PyDict_SetItemString(dict, "headers", headerdict);

		Py_XDECREF(headerdict);


	} else {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Unknown input type: %d\n", itype);
		return SWITCH_STATUS_FALSE;
	}


	if (!arglist) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "error building arglist");
		return SWITCH_STATUS_FALSE;
	}

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "run_dtmf_callback end_allow_threads\n");
	did_swap_in = end_allow_threads();

	pyresult = PyEval_CallObject(func, arglist);


	Py_XDECREF(arglist);		// Trash arglist

	if (pyresult && pyresult != Py_None) {
		resultStr = (char *) PyString_AsString(pyresult);
		switch_status_t cbresult = process_callback_result(resultStr);
		return cbresult;
	} else {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "Python callback\n returned None");
		PyErr_Print();
		PyErr_Clear();
	}

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "run_dtmf_callback begin_allow_threads\n");
	if (did_swap_in) {
		begin_allow_threads();
	}

	Py_XDECREF(pyresult);

	return SWITCH_STATUS_SUCCESS;

}

bool PySession::begin_allow_threads(void)
{
	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "PySession::begin_allow_threads() called\n");

	if (!session) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "No valid session\n");
		return false;
	}
	// swap out threadstate and store in instance variable 
	switch_channel_t *channel = switch_core_session_get_channel(session);
	PyThreadState *swapin_tstate = (PyThreadState *) switch_channel_get_private(channel, "SwapInThreadState");
	// so lets assume the thread state was swapped in when the python script was started,
	// therefore swapin_tstate will be NULL (because there is nothing to swap in, since its 
	// _already_ swapped in.)
	if (swapin_tstate == NULL) {
		// currently swapped in
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "Threadstate swap-out!\n");
		swapin_tstate = PyEval_SaveThread();
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "swapin_tstate: %p\n", swapin_tstate);
		// give future swapper-inners something to actually swap in
		switch_channel_set_private(channel, "SwapInThreadState", (void *) swapin_tstate);
		cb_state.threadState = threadState;	// TODO: get rid of this
		args.buf = &cb_state;
		ap = &args;
		return true;

	} else {
		// currently swapped out
		return false;
	}

}

bool PySession::end_allow_threads(void)
{
	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "PySession::end_allow_threads() called\n");
	// swap in threadstate from instance variable saved earlier
	if (!session) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_WARNING, "No valid session\n");
		return false;
	}

	switch_channel_t *channel = switch_core_session_get_channel(session);
	PyThreadState *swapin_tstate = (PyThreadState *) switch_channel_get_private(channel, "SwapInThreadState");
	if (swapin_tstate == NULL) {
		// currently swapped in
		return false;
	} else {
		// currently swapped out
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "Threadstate swap-in!\n");
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "swapin_tstate: %p\n", swapin_tstate);
		PyEval_RestoreThread(swapin_tstate);
		// dont give any swapper-inners the opportunity to do a double swap
		switch_channel_set_private(channel, "SwapInThreadState", NULL);
		return true;
	}


}

void PySession::hangup(char *cause)
{


	// since we INCREF'd this function pointer earlier (so the py gc didnt reclaim it)
	// we have to DECREF it, or else the PySession dtor will never get called and
	// a zombie channel will be left over using up resources

	if (cb_state.function != NULL) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "xdecref on cb_state_function\n");
		PyObject *func = (PyObject *) cb_state.function;
		Py_XDECREF(func);
	} else {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "cb_state.function is null\n");
	}


	CoreSession::hangup(cause);

}


PySession::~PySession()
{
	// Should we do any cleanup here?
	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "PySession::~PySession started\n");

	if (on_hangup) {
		PyObject *func = (PyObject *) on_hangup;
		Py_XDECREF(func);
	}


	if (cb_state.function != NULL) {
		PyObject *func = (PyObject *) cb_state.function;
		Py_XDECREF(func);
	}

	switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "PySession::~PySession finished\n");

}