~siretart/lcd4linux/debian

/* $Id: plugin_python.c 1086 2010-01-19 14:26:33Z mzuther $

 * $URL: https://ssl.bulix.org/svn/lcd4linux/trunk/plugin_python.c $

 *

 * Python plugin

 *

 * Copyright 2005 Dan Fritz  

 * Copyright 2005 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>

 *

 * This file is part of LCD4Linux.

 *

 * LCD4Linux is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2, or (at your option)

 * any later version.

 *

 * LCD4Linux is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 *

 */

/* 

 * exported functions:

 *

 * int plugin_init_python (void)

 *  adds a python interpreter

 * 

 */

#include "config.h"

#include <Python.h>

#include "debug.h"

#include "plugin.h"

/* 

 * Executes a python function specified by function name and module.

 *

 * This method is more or less a copy of an example found in the python 

 * documentation. Kudos goes to Guido van Rossum and Fred L. Drake.

 * 

 * Fixme: this function should be able to accept and receive any types 

 * of arguments supported by the evaluator. Right now only strings are accepted.

 */

static void pyt_exec_str(RESULT * result, const char *module, const char *function, int argc, const char *argv[])

{

    PyObject *pName, *pModule, *pDict, *pFunc;

    PyObject *pArgs, *pValue;

    const char *rv = NULL;

    int i;

    pName = PyString_FromString(module);

    /* Error checking of pName left out */

    pModule = PyImport_Import(pName);

    Py_DECREF(pName);

    if (pModule != NULL) {

	pDict = PyModule_GetDict(pModule);

	/* pDict is a borrowed reference */

	pFunc = PyDict_GetItemString(pDict, function);

	/* pFun: Borrowed reference */

	if (pFunc && PyCallable_Check(pFunc)) {

	    pArgs = PyTuple_New(argc);

	    for (i = 0; i < argc; ++i) {

		pValue = PyString_FromString(argv[i]);

		if (!pValue) {

		    Py_DECREF(pArgs);

		    Py_DECREF(pModule);

		    error("Cannot convert argument \"%s\" to python format", argv[i]);

		    SetResult(&result, R_STRING, "");

		    return;

		}

		/* pValue reference stolen here: */

		PyTuple_SetItem(pArgs, i, pValue);

	    }

	    pValue = PyObject_CallObject(pFunc, pArgs);

	    Py_DECREF(pArgs);

	    if (pValue != NULL) {

		rv = PyString_AsString(pValue);

		SetResult(&result, R_STRING, rv);

		Py_DECREF(pValue);

		/* rv is now a 'dangling reference' */

		return;

	    } else {

		Py_DECREF(pModule);

		error("Python call failed (\"%s.%s\")", module, function);

		/* print traceback on stderr */

		PyErr_PrintEx(0);

		SetResult(&result, R_STRING, "");

		return;

	    }

	    /* pDict and pFunc are borrowed and must not be Py_DECREF-ed */

	} else {

	    error("Can not find python function \"%s.%s\"", module, function);

	}

	Py_DECREF(pModule);

    } else {

	error("Failed to load python module \"%s\"", module);

	/* print traceback on stderr */

	PyErr_PrintEx(0);

    }

    SetResult(&result, R_STRING, "");

    return;

}

static int python_cleanup_responsibility = 0;

static void my_exec(RESULT * result, RESULT * module, RESULT * function, RESULT * arg)

{

    /* Fixme: a plugin should be able to accept any number of arguments, don't know how

       to code that (yet) */

    const char *args[] = { R2S(arg) };

    pyt_exec_str(result, R2S(module), R2S(function), 1, args);

}

int plugin_init_python(void)

{

    if (!Py_IsInitialized()) {

	Py_Initialize();

	python_cleanup_responsibility = 1;

    }

    AddFunction("python::exec", 3, my_exec);

    return 0;

}

void plugin_exit_python(void)

{

    /* Make sure NOT to call Py_Finalize() When (and if) the entire lcd4linux process 

     * is started from inside python

     */

    if (python_cleanup_responsibility) {

	python_cleanup_responsibility = 0;

	Py_Finalize();

    }

}