path: root/glib/pyglib.c

/* -*- Mode: C; c-set-style: python; c-basic-offset: 4  -*-
 * pyglib - Python bindings for GLib toolkit.
 * Copyright (C) 1998-2003  James Henstridge
 *               2004-2008  Johan Dahlin
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 * USA
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <Python.h>
#include <pythread.h>
#include "pyglib.h"
#include "pyglib-private.h"
#include "pygmaincontext.h"
#include "pygoptioncontext.h"
#include "pygoptiongroup.h"

static struct _PyGLib_Functions *_PyGLib_API;
static int pyglib_thread_state_tls_key;
static PyObject *exception_table = NULL;

static PyTypeObject *_PyGMainContext_Type;
#define PyGMainContext_Type (*_PyGMainContext_Type)

static PyTypeObject *_PyGOptionGroup_Type;
#define PyGOptionGroup_Type (*_PyGOptionGroup_Type)

static PyTypeObject *_PyGOptionContext_Type;
#define PyGOptionContext_Type (*_PyGOptionContext_Type)

void
pyglib_init(void)
{
    PyObject *glib, *cobject;
    
    glib = PyImport_ImportModule("glib");
    if (!glib) {
	if (PyErr_Occurred()) {
	    PyObject *type, *value, *traceback;
	    PyObject *py_orig_exc;
	    PyErr_Fetch(&type, &value, &traceback);
	    py_orig_exc = PyObject_Repr(value);
	    Py_XDECREF(type);
	    Py_XDECREF(value);
	    Py_XDECREF(traceback);
	    PyErr_Format(PyExc_ImportError,
			 "could not import glib (error was: %s)",
			 _PyUnicode_AsString(py_orig_exc));
	    Py_DECREF(py_orig_exc);
        } else {
	    PyErr_SetString(PyExc_ImportError,
			    "could not import glib (no error given)");
	}
	return;
    }
    
    cobject = PyObject_GetAttrString(glib, "_PyGLib_API");
    if (cobject && PyCObject_Check(cobject))
	_PyGLib_API = (struct _PyGLib_Functions *) PyCObject_AsVoidPtr(cobject);
    else {
	PyErr_SetString(PyExc_ImportError,
			"could not import glib (could not find _PyGLib_API object)");
	Py_DECREF(glib);
	return;
    }

    _PyGMainContext_Type = (PyTypeObject*)PyObject_GetAttrString(glib, "MainContext");
    _PyGOptionGroup_Type = (PyTypeObject*)PyObject_GetAttrString(glib, "OptionGroup");
    _PyGOptionContext_Type = (PyTypeObject*)PyObject_GetAttrString(glib, "OptionContext");
}

void
pyglib_init_internal(PyObject *api)
{
    _PyGLib_API = (struct _PyGLib_Functions *) PyCObject_AsVoidPtr(api);
}

gboolean
pyglib_threads_enabled(void)
{
    g_return_val_if_fail (_PyGLib_API != NULL, FALSE);

    return _PyGLib_API->threads_enabled;
}

PyGILState_STATE
pyglib_gil_state_ensure(void)
{
    g_return_val_if_fail (_PyGLib_API != NULL, PyGILState_LOCKED);

    if (!_PyGLib_API->threads_enabled)
	return PyGILState_LOCKED;

    return PyGILState_Ensure();
}

void
pyglib_gil_state_release(PyGILState_STATE state)
{
    g_return_if_fail (_PyGLib_API != NULL);

    if (!_PyGLib_API->threads_enabled)
	return;

    PyGILState_Release(state);
}

/**
 * pyglib_enable_threads:
 *
 * Returns: TRUE if threading is enabled, FALSE otherwise.
 *
 */
#ifdef DISABLE_THREADING
gboolean
pyglib_enable_threads(void)
{
    PyErr_SetString(PyExc_RuntimeError,
		    "pyglib threading disabled at compile time");
    return FALSE;
}

void
_pyglib_notify_on_enabling_threads(PyGLibThreadsEnabledFunc callback)
{
    /* Ignore, threads cannot be enabled. */
}

#else

static GSList *thread_enabling_callbacks = NULL;

/* Enable threading; note that the GIL must be held by the current
 * thread when this function is called
 */
gboolean
pyglib_enable_threads(void)
{
    GSList *callback;

    g_return_val_if_fail (_PyGLib_API != NULL, FALSE);

    if (_PyGLib_API->threads_enabled)
	return TRUE;
  
    PyEval_InitThreads();
    if (!g_threads_got_initialized)
	g_thread_init(NULL);
    
    _PyGLib_API->threads_enabled = TRUE;
    pyglib_thread_state_tls_key = PyThread_create_key();

    for (callback = thread_enabling_callbacks; callback; callback = callback->next)
	((PyGLibThreadsEnabledFunc) callback->data) ();

    g_slist_free(thread_enabling_callbacks);
    return TRUE;
}

void
_pyglib_notify_on_enabling_threads(PyGLibThreadsEnabledFunc callback)
{
    if (callback && !pyglib_threads_enabled())
	thread_enabling_callbacks = g_slist_append(thread_enabling_callbacks, callback);
}
#endif

int
pyglib_gil_state_ensure_py23 (void)
{
    return PyGILState_Ensure();
}

void
pyglib_gil_state_release_py23 (int flag)
{
    PyGILState_Release(flag);
}

/**
 * pyglib_block_threads:
 *
 */
void
pyglib_block_threads(void)
{
    g_return_if_fail (_PyGLib_API != NULL);

    if (_PyGLib_API->block_threads != NULL)
	(* _PyGLib_API->block_threads)();
}

/**
 * pyglib_unblock_threads:
 *
 */
void
pyglib_unblock_threads(void)
{
    g_return_if_fail (_PyGLib_API != NULL);
    if (_PyGLib_API->unblock_threads != NULL)
	(* _PyGLib_API->unblock_threads)();
}

/**
 * pyglib_set_thread_block_funcs:
 *
 * hooks to register handlers for getting GDK threads to cooperate
 * with python threading
 */
void
pyglib_set_thread_block_funcs (PyGLibThreadBlockFunc block_threads_func,
			       PyGLibThreadBlockFunc unblock_threads_func)
{
    g_return_if_fail (_PyGLib_API != NULL);

    _PyGLib_API->block_threads = block_threads_func;
    _PyGLib_API->unblock_threads = unblock_threads_func;
}


/**
 * pyglib_error_check:
 * @error: a pointer to the GError.
 *
 * Checks to see if the GError has been set.  If the error has been
 * set, then the glib.GError Python exception will be raised, and
 * the GError cleared.
 *
 * Returns: True if an error was set.
 */
gboolean
pyglib_error_check(GError **error)
{
    PyGILState_STATE state;
    PyObject *exc_type;
    PyObject *exc_instance;
    PyObject *d;

    g_return_val_if_fail(error != NULL, FALSE);

    if (*error == NULL)
	return FALSE;
    
    state = pyglib_gil_state_ensure();

    exc_type = _PyGLib_API->gerror_exception;
    if (exception_table != NULL)
    {
	PyObject *item;
	item = PyDict_GetItem(exception_table, _PyLong_FromLong((*error)->domain));
	if (item != NULL)
	    exc_type = item;
    }

    exc_instance = PyObject_CallFunction(exc_type, "z", (*error)->message);

    if ((*error)->domain) {
	PyObject_SetAttrString(exc_instance, "domain",
			       d=_PyUnicode_FromString(g_quark_to_string((*error)->domain)));
	Py_DECREF(d);
    }
    else
	PyObject_SetAttrString(exc_instance, "domain", Py_None);

    PyObject_SetAttrString(exc_instance, "code",
			   d=_PyLong_FromLong((*error)->code));
    Py_DECREF(d);

    if ((*error)->message) {
	PyObject_SetAttrString(exc_instance, "message",
			       d=_PyUnicode_FromString((*error)->message));
	Py_DECREF(d);
    } else {
	PyObject_SetAttrString(exc_instance, "message", Py_None);
    }
    
    PyErr_SetObject(_PyGLib_API->gerror_exception, exc_instance);
    Py_DECREF(exc_instance);
    g_clear_error(error);
    
    pyglib_gil_state_release(state);
    
    return TRUE;
}

/**
 * pyglib_gerror_exception_check:
 * @error: a standard GLib GError ** output parameter
 *
 * Checks to see if a GError exception has been raised, and if so
 * translates the python exception to a standard GLib GError.  If the
 * raised exception is not a GError then PyErr_Print() is called.
 *
 * Returns: 0 if no exception has been raised, -1 if it is a
 * valid glib.GError, -2 otherwise.
 */
gboolean
pyglib_gerror_exception_check(GError **error)
{
    PyObject *type, *value, *traceback;
    PyObject *py_message, *py_domain, *py_code;
    const char *bad_gerror_message;

    PyErr_Fetch(&type, &value, &traceback);
    if (type == NULL)
        return 0;
    PyErr_NormalizeException(&type, &value, &traceback);
    if (value == NULL) {
        PyErr_Restore(type, value, traceback);
        PyErr_Print();
        return -2;
    }
    if (!value ||
	!PyErr_GivenExceptionMatches(type,
				     (PyObject *) _PyGLib_API->gerror_exception)) {
        PyErr_Restore(type, value, traceback);
        PyErr_Print();
        return -2;
    }
    Py_DECREF(type);
    Py_XDECREF(traceback);

    py_message = PyObject_GetAttrString(value, "message");
    if (!py_message || !_PyUnicode_Check(py_message)) {
        bad_gerror_message = "glib.GError instances must have a 'message' string attribute";
        goto bad_gerror;
    }

    py_domain = PyObject_GetAttrString(value, "domain");
    if (!py_domain || !_PyUnicode_Check(py_domain)) {
        bad_gerror_message = "glib.GError instances must have a 'domain' string attribute";
        Py_DECREF(py_message);
        goto bad_gerror;
    }

    py_code = PyObject_GetAttrString(value, "code");
    if (!py_code || !_PyLong_Check(py_code)) {
        bad_gerror_message = "glib.GError instances must have a 'code' int attribute";
        Py_DECREF(py_message);
        Py_DECREF(py_domain);
        goto bad_gerror;
    }

    g_set_error(error, g_quark_from_string(_PyUnicode_AsString(py_domain)),
                _PyLong_AsLong(py_code), _PyUnicode_AsString(py_message));

    Py_DECREF(py_message);
    Py_DECREF(py_code);
    Py_DECREF(py_domain);
    return -1;

bad_gerror:
    Py_DECREF(value);
    g_set_error(error, g_quark_from_static_string("pyglib"), 0, bad_gerror_message);
    PyErr_SetString(PyExc_ValueError, bad_gerror_message);
    PyErr_Print();
    return -2;
}

/**
 * pyglib_register_exception_for_domain:
 * @name: name of the exception
 * @error_domain: error domain
 *
 * Registers a new glib.GError exception subclass called #name for
 * a specific #domain. This exception will be raised when a GError
 * of the same domain is passed in to pyglib_error_check().
 *
 * Returns: the new exception
 */
PyObject *
pyglib_register_exception_for_domain(gchar *name,
				     gint error_domain)
{
    PyObject *exception;

    exception = PyErr_NewException(name, _PyGLib_API->gerror_exception, NULL);

    if (exception_table == NULL)
	exception_table = PyDict_New();

    PyDict_SetItem(exception_table,
		   _PyLong_FromLong(error_domain),
		   exception);
    
    return exception;
}

/**
 * pyglib_main_context_new:
 * @context: a GMainContext.
 *
 * Creates a wrapper for a GMainContext.
 *
 * Returns: the GMainContext wrapper.
 */
PyObject *
pyglib_main_context_new(GMainContext *context)
{
    PyGMainContext *self;

    self = (PyGMainContext *)PyObject_NEW(PyGMainContext,
					  &PyGMainContext_Type);
    if (self == NULL)
	return NULL;

    self->context = g_main_context_ref(context);
    return (PyObject *)self;
}

/**
 * pyg_option_group_transfer_group:
 * @group: a GOptionGroup wrapper
 *
 * This is used to transfer the GOptionGroup to a GOptionContext. After this
 * is called, the calle must handle the release of the GOptionGroup.
 *
 * When #NULL is returned, the GOptionGroup was already transfered.
 *
 * Returns: Either #NULL or the wrapped GOptionGroup.
 */
GOptionGroup *
pyglib_option_group_transfer_group(PyObject *obj)
{
    PyGOptionGroup *self = (PyGOptionGroup*)obj;
    
    if (self->is_in_context)
	return NULL;

    self->is_in_context = TRUE;
    
    /* Here we increase the reference count of the PyGOptionGroup, because now
     * the GOptionContext holds an reference to us (it is the userdata passed
     * to g_option_group_new().
     *
     * The GOptionGroup is freed with the GOptionContext.
     *
     * We set it here because if we would do this in the init method we would
     * hold two references and the PyGOptionGroup would never be freed.
     */
    Py_INCREF(self);
    
    return self->group;
}

/**
 * pyglib_option_group_new:
 * @group: a GOptionGroup
 *
 * The returned GOptionGroup can't be used to set any hooks, translation domains
 * or add entries. It's only intend is, to use for GOptionContext.add_group().
 *
 * Returns: the GOptionGroup wrapper.
 */
PyObject * 
pyglib_option_group_new (GOptionGroup *group)
{
    PyGOptionGroup *self;

    self = (PyGOptionGroup *)PyObject_NEW(PyGOptionGroup,
					  &PyGOptionGroup_Type);
    if (self == NULL)
	return NULL;

    self->group = group;
    self->other_owner = TRUE;
    self->is_in_context = FALSE;
        
    return (PyObject *)self;
}

/**
 * pyglib_option_context_new:
 * @context: a GOptionContext
 *
 * Returns: A new GOptionContext wrapper.
 */
PyObject * 
pyglib_option_context_new (GOptionContext *context)
{
    PyGOptionContext *self;

    self = (PyGOptionContext *)PyObject_NEW(PyGOptionContext,
					    &PyGOptionContext_Type);
    if (self == NULL)
	return NULL;

    self->context = context;
    self->main_group = NULL;
    
    return (PyObject *)self;
}

/**
 * pyglib_option_context_new:
 * @context: a GTimeVal struct
 *
 * Converts a GTimeVal struct to a python float
 *
 * Returns: a float representing the timeval
 */
PyObject *
pyglib_float_from_timeval(GTimeVal timeval)
{
    double ret;
    ret = (double)timeval.tv_sec + (double)timeval.tv_usec * 0.000001;
    return PyFloat_FromDouble(ret);
}


/****** Private *****/

/**
 * _pyglib_destroy_notify:
 * @user_data: a PyObject pointer.
 *
 * A function that can be used as a GDestroyNotify callback that will
 * call Py_DECREF on the data.
 */
void
_pyglib_destroy_notify(gpointer user_data)
{
    PyObject *obj = (PyObject *)user_data;
    PyGILState_STATE state;

    g_return_if_fail (_PyGLib_API != NULL);

    state = pyglib_gil_state_ensure();
    Py_DECREF(obj);
    pyglib_gil_state_release(state);
}

gboolean
_pyglib_handler_marshal(gpointer user_data)
{
    PyObject *tuple, *ret;
    gboolean res;
    PyGILState_STATE state;

    g_return_val_if_fail(user_data != NULL, FALSE);

    state = pyglib_gil_state_ensure();

    tuple = (PyObject *)user_data;
    ret = PyObject_CallObject(PyTuple_GetItem(tuple, 0),
			      PyTuple_GetItem(tuple, 1));
    if (!ret) {
	PyErr_Print();
	res = FALSE;
    } else {
	res = PyObject_IsTrue(ret);
	Py_DECREF(ret);
    }
    
    pyglib_gil_state_release(state);

    return res;
}