Commit 9a5a1e8e authored by Edward Hervey's avatar Edward Hervey 🤘

Python plugin loader implementation.

Fixes #304361.
parent 3a000eca
SUBDIRS = common codegen gst examples testsuite pkgconfig
SUBDIRS = common codegen gst examples plugin testsuite pkgconfig
common_cflags = $(PYTHON_INCLUDES) $(PYGOBJECT_CFLAGS) $(GST_CFLAGS) $(GST_OPTION_CFLAGS) -fno-strict-aliasing
common_libadd = $(GST_LIBS) $(GST_OPTION_LIBS)
......
......@@ -64,3 +64,24 @@ $1],dnl
$2])
CPPFLAGS="$save_CPPFLAGS"
])
dnl a macro to check for ability to embed python
dnl AM_CHECK_PYTHON_LIBS([ACTION-IF-POSSIBLE], [ACTION-IF-NOT-POSSIBLE])
dnl function also defines PYTHON_LIBS
AC_DEFUN([AM_CHECK_PYTHON_LIBS],
[AC_REQUIRE([AM_CHECK_PYTHON_HEADERS])
AC_MSG_CHECKING(for libraries required to embed python)
dnl deduce PYTHON_LIBS
py_exec_prefix=`$PYTHON -c "import sys; print sys.exec_prefix"`
PYTHON_LIBS="-L${py_prefix}/lib -lpython${PYTHON_VERSION}"
PYTHON_LIB_LOC="${py_prefix}/lib"
AC_SUBST(PYTHON_LIBS)
AC_SUBST(PYTHON_LIB_LOC)
dnl check if the headers exist:
save_LIBS="$LIBS"
LIBS="$LIBS $PYTHON_LIBS"
AC_TRY_LINK_FUNC(Py_Initialize, dnl
[LIBS="$save_LIBS"; AC_MSG_RESULT(yes); $1], dnl
[LIBS="$save_LIBS"; AC_MSG_RESULT(no); $2])
])
......@@ -83,6 +83,7 @@ dnl check for GStreamer
GST_MAJORMINOR=0.10
AC_SUBST(GST_MAJORMINOR)
PKG_CHECK_MODULES(GST, gstreamer-$GST_MAJORMINOR >= $GST_REQ)
AC_DEFINE_UNQUOTED(GST_MAJORMINOR, "$GST_MAJORMINOR", [Gst MajorMinor version])
AC_SUBST(GST_CFLAGS)
AC_SUBST(GST_LIBS)
......@@ -358,6 +359,13 @@ dnl add debugging options ...
AG_GST_VALGRIND_CHECK
dnl Stuff needed for the python plugin loader
AM_CHECK_PYTHON_LIBS(,[AC_MSG_ERROR(could not find Python lib)])
AG_GST_SET_PLUGINDIR
AC_OUTPUT([
Makefile
codegen/Makefile
......@@ -370,6 +378,7 @@ AC_OUTPUT([
pkgconfig/Makefile
pkgconfig/gst-python.pc
pkgconfig/gst-python-uninstalled.pc
plugin/Makefile
testsuite/Makefile
win32/common/config.h
gst-python.spec
......
plugin_LTLIBRARIES = libgstpython.la
INCLUDES = $(PYGOBJECT_CFLAGS) $(GST_CFLAGS)\
-DPYTHON_VERSION=\"$(PYTHON_VERSION)\" \
-DPY_LIB_LOC="\"$(PYTHON_LIB_LOC)\"" \
$(PYTHON_INCLUDES)
libgstpython_la_SOURCES = gstpythonplugin.c
#libgstpython_la_CFLAGS = $(PYGTK_CFLAGS) $(GST_CFLAGS)
#libgstpython_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS) -avoid-version -module # $(PYTHON_LIBS) -lpython2.4
libgstpython_la_LDFLAGS = -module -avoid-version
libgstpython_la_LIBADD = $(GST_LIBS) $(PYTHON_LIBS)
/* gst-python
* Copyright (C) 2009 Edward Hervey <bilboed@bilboed.com>
* 2005 Benjamin Otte <otte@gnome.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
/* include this first, before NO_IMPORT_PYGOBJECT is defined */
#include <pygobject.h>
#include <gst/gst.h>
PyTypeObject *_PyGstElement_Type;
#define PyGstElement_Type (*_PyGstElement_Type)
GST_DEBUG_CATEGORY_STATIC (pyplugindebug);
#define GST_CAT_DEFAULT pyplugindebug
#define GST_ORIGIN "http://gstreamer.freedesktop.org"
static PyObject *element;
static inline gboolean
np_init_pygobject (void)
{
PyObject *gobject = PyImport_ImportModule ("gobject");
gboolean res = TRUE;
if (gobject != NULL) {
PyObject *mdict = PyModule_GetDict (gobject);
PyObject *cobject = PyDict_GetItemString (mdict, "_PyGObject_API");
if (PyCObject_Check (cobject)) {
_PyGObject_API =
(struct _PyGObject_Functions *) PyCObject_AsVoidPtr (cobject);
} else {
PyErr_SetString (PyExc_RuntimeError,
"could not find _PyGObject_API object");
PyErr_Print ();
res = FALSE;
goto beach;
}
if (!(PyObject_CallMethod (gobject, "threads_init", NULL, NULL))) {
PyErr_SetString (PyExc_RuntimeError, "Could not initialize threads");
PyErr_Print ();
res = FALSE;
goto beach;
}
} else {
PyErr_Print ();
GST_WARNING ("could not import gobject");
res = FALSE;
}
beach:
return res;
}
static gboolean
gst_python_plugin_load_file (GstPlugin * plugin, const char *name)
{
PyObject *main_module, *main_locals;
PyObject *elementfactory;
int pos = 0;
GType gtype;
PyObject *module;
const gchar *facname;
guint rank;
PyObject *class;
GST_DEBUG ("loading plugin %s", name);
main_module = PyImport_AddModule ("__main__");
if (main_module == NULL) {
GST_WARNING ("Could not get __main__, ignoring plugin %s", name);
PyErr_Print ();
PyErr_Clear ();
return FALSE;
}
main_locals = PyModule_GetDict (main_module);
module =
PyImport_ImportModuleEx ((char *) name, main_locals, main_locals, NULL);
if (!module) {
GST_DEBUG ("Could not load module, ignoring plugin %s", name);
PyErr_Print ();
PyErr_Clear ();
return FALSE;
}
/* Get __gstelementfactory__ from file */
elementfactory = PyObject_GetAttrString (module, "__gstelementfactory__");
if (!elementfactory) {
GST_DEBUG ("python file doesn't contain __gstelementfactory__");
PyErr_Clear ();
return FALSE;
}
/* parse tuple : name, rank, gst.ElementClass */
if (!PyArg_ParseTuple (elementfactory, "sIO", &facname, &rank, &class)) {
GST_WARNING ("__gstelementfactory__ isn't correctly formatted");
PyErr_Print ();
PyErr_Clear ();
Py_DECREF (elementfactory);
return FALSE;
}
if (!PyType_Check (class)
|| !(PyObject_IsSubclass (class, (PyObject *) & PyGstElement_Type))) {
GST_WARNING ("the class provided isn't a subclass of gst.Element");
PyErr_Print ();
PyErr_Clear ();
Py_DECREF (elementfactory);
Py_DECREF (class);
}
GST_LOG ("Valid plugin");
Py_DECREF (elementfactory);
return gst_element_register (plugin, facname, rank,
pyg_type_from_object (class));
}
static gboolean
gst_python_load_directory (GstPlugin * plugin, gchar * path)
{
GST_LOG ("Checking for python plugins in %s", path);
GDir *dir;
const gchar *file;
GError *error = NULL;
gboolean ret = TRUE;
dir = g_dir_open (path, 0, &error);
if (!dir) {
/*retval should probably be depending on error, but since we ignore it... */
GST_WARNING ("Couldn't open Python plugin dir: %s", error->message);
g_error_free (error);
return FALSE;
}
while ((file = g_dir_read_name (dir))) {
/* FIXME : go down in subdirectories */
if (g_str_has_suffix (file, ".py")) {
gsize len = strlen (file) - 3;
gchar *name = g_strndup (file, len);
ret &= gst_python_plugin_load_file (plugin, name);
g_free (name);
}
}
return TRUE;
}
static gboolean
gst_python_plugin_load (GstPlugin * plugin)
{
PyObject *sys_path;
const gchar *plugin_path;
gboolean ret = TRUE;
sys_path = PySys_GetObject ("path");
/* Mimic the order in which the registry is checked in core */
/* 1. check env_variable GST_PLUGIN_PATH */
plugin_path = g_getenv ("GST_PLUGIN_PATH");
if (plugin_path) {
char **list;
int i;
GST_DEBUG ("GST_PLUGIN_PATH set to %s", plugin_path);
list = g_strsplit (plugin_path, G_SEARCHPATH_SEPARATOR_S, 0);
for (i = 0; list[i]; i++) {
gchar *sysdir = g_build_filename (list[i], "python", NULL);
PyList_Insert (sys_path, 0, PyString_FromString (sysdir));
gst_python_load_directory (plugin, sysdir);
g_free (sysdir);
}
g_strfreev (list);
}
/* 2. Check for GST_PLUGIN_SYSTEM_PATH */
plugin_path = g_getenv ("GST_PLUGIN_SYSTEM_PATH");
if (plugin_path == NULL) {
char *home_plugins;
/* 2.a. Scan user and system-wide plugin directory */
GST_DEBUG ("GST_PLUGIN_SYSTEM_PATH not set");
/* plugins in the user's home directory take precedence over
* system-installed ones */
home_plugins = g_build_filename (g_get_home_dir (),
".gstreamer-" GST_MAJORMINOR, "plugins", "python", NULL);
PyList_Insert (sys_path, 0, PyString_FromString (home_plugins));
gst_python_load_directory (plugin, home_plugins);
g_free (home_plugins);
/* add the main (installed) library path */
PyList_Insert (sys_path, 0, PyString_FromString (PLUGINDIR "/python"));
gst_python_load_directory (plugin, PLUGINDIR "/python");
} else {
gchar **list;
gint i;
/* 2.b. Scan GST_PLUGIN_SYSTEM_PATH */
GST_DEBUG ("GST_PLUGIN_SYSTEM_PATH set to %s", plugin_path, plugin_path);
list = g_strsplit (plugin_path, G_SEARCHPATH_SEPARATOR_S, 0);
for (i = 0; list[i]; i++) {
gchar *sysdir;
sysdir = g_build_filename (list[i], "python", NULL);
PyList_Insert (sys_path, 0, PyString_FromString (sysdir));
gst_python_load_directory (plugin, sysdir);
g_free (sysdir);
}
g_strfreev (list);
}
return ret;
}
/**
*pygst_require:
* @version: the version required
*
* Checks if the pygst/gst python modules are available.
* Requests the specified version.
*
* Returns: the gst-python module, or NULL if there was an error.
*/
static PyObject *
pygst_require (gchar * version)
{
PyObject *pygst, *gst;
PyObject *require;
if (!(pygst = PyImport_ImportModule ("pygst"))) {
GST_ERROR ("the pygst module is not available!");
goto error;
}
if (!(PyObject_CallMethod (pygst, "require", "s", version))) {
GST_ERROR ("the required version, %s, of gst-python is not available!");
Py_DECREF (pygst);
goto error;
}
if (!(gst = PyImport_ImportModule ("gst"))) {
GST_ERROR ("couldn't import the gst module");
Py_DECREF (pygst);
goto error;
}
#define IMPORT(x, y) \
_PyGst##x##_Type = (PyTypeObject *)PyObject_GetAttrString(gst, y); \
if (_PyGst##x##_Type == NULL) { \
PyErr_Print(); \
return NULL; \
}
IMPORT (Element, "Element");
return gst;
error:
{
PyErr_Print ();
PyErr_Clear ();
return NULL;
}
}
static gboolean
plugin_init (GstPlugin * plugin)
{
PyGILState_STATE state;
PyObject *gst, *dict, *pyplugin;
gboolean we_initialized = FALSE;
GModule *libpython;
gpointer has_python = NULL;
GST_DEBUG_CATEGORY_INIT (pyplugindebug, "pyplugin", 0,
"Python plugin loader");
gst_plugin_add_dependency_simple (plugin,
"HOME/.gstreamer-0.10/plugins/python:GST_PLUGIN_SYSTEM_PATH/python:GST_PLUGIN_PATH/python",
NULL, NULL, GST_PLUGIN_DEPENDENCY_FLAG_NONE);
GST_LOG ("Checking to see if libpython is already loaded");
g_module_symbol (g_module_open (NULL, G_MODULE_BIND_LOCAL), "Py_None",
&has_python);
if (has_python) {
GST_LOG ("libpython is already loaded");
} else {
GST_LOG ("loading libpython");
libpython =
g_module_open (PY_LIB_LOC "/libpython" PYTHON_VERSION "."
G_MODULE_SUFFIX, 0);
if (!libpython) {
GST_WARNING ("Couldn't g_module_open libpython. Reason: %s",
g_module_error ());
return FALSE;
}
}
if (!Py_IsInitialized ()) {
GST_LOG ("python wasn't initialized");
/* set the correct plugin for registering stuff */
Py_Initialize ();
we_initialized = TRUE;
} else {
GST_LOG ("python was already initialized");
state = pyg_gil_state_ensure ();
}
GST_LOG ("initializing pygobject");
if (!np_init_pygobject ()) {
GST_WARNING ("pygobject initialization failed");
return FALSE;
}
if (!(gst = pygst_require ("0.10"))) {
return FALSE;
}
if (we_initialized) {
pyplugin = pygobject_new (G_OBJECT (plugin));
if (!pyplugin || PyModule_AddObject (gst, "__plugin__", pyplugin) != 0) {
g_warning ("Couldn't set plugin");
Py_DECREF (pyplugin);
}
}
dict = PyModule_GetDict (gst);
if (!dict) {
GST_ERROR ("no dict?!");
return FALSE;
}
gst_python_plugin_load (plugin);
if (we_initialized) {
/* We need to release the GIL since we're going back to C land */
PyEval_SaveThread ();
} else
pyg_gil_state_release (state);
return TRUE;
}
GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
GST_VERSION_MINOR,
"python",
"loader for plugins written in python",
plugin_init, VERSION, "LGPL", PACKAGE_NAME, GST_ORIGIN)
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