gstreamer/subprojects/gst-python/plugin/gstpythonplugin.c

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/* 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>
#include <Python.h>
/*
* We need to call dlopen() directly on macOS to workaround a macOS runtime
* linker bug. When there are nested dlopen() calls and the second dlopen() is
* called from another library (such as gmodule), @loader_path is resolved as
* @executable_path and RPATHs are read from the executable (gst-plugin-scanner)
* instead of the library itself (libgstges.dylib). This doesn't happen if the
* second dlopen() call is directly in the source code of the library.
* Previously seen at:
* https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1171#note_2290789
*/
#ifdef G_OS_WIN32
#include <gmodule.h>
#define gstpy_module_open(fname) g_module_open(fname,0)
#define gstpy_module_error g_module_error
#define gstpy_module_symbol(module,name,symbol) g_module_symbol(module,name,symbol)
#else
#include <dlfcn.h>
#define gstpy_module_open(fname) dlopen(fname,RTLD_NOW | RTLD_GLOBAL)
#define gstpy_module_error dlerror
static inline gboolean
gstpy_module_symbol (gpointer handle, const char *name, gpointer * symbol)
{
*symbol = dlsym (handle, name);
return *symbol != NULL;
}
#endif
void *_PyGstElement_Type;
GST_DEBUG_CATEGORY_STATIC (pyplugindebug);
#define GST_CAT_DEFAULT pyplugindebug
#define GST_ORIGIN "http://gstreamer.freedesktop.org"
static gboolean
gst_python_plugin_load_file (GstPlugin * plugin, const char *name)
{
PyObject *main_module, *main_locals;
PyObject *elementfactory;
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 (!PyObject_IsSubclass (class, (PyObject *) & PyGObject_Type)) {
GST_WARNING ("the class provided isn't a subclass of GObject.Object");
PyErr_Print ();
PyErr_Clear ();
Py_DECREF (elementfactory);
Py_DECREF (class);
return FALSE;
}
if (!g_type_is_a (pyg_type_from_object (class), GST_TYPE_ELEMENT)) {
GST_WARNING ("the class provided isn't a subclass of Gst.Element");
PyErr_Print ();
PyErr_Clear ();
Py_DECREF (elementfactory);
Py_DECREF (class);
return FALSE;
}
GST_INFO ("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, const gchar * path)
{
GDir *dir;
const gchar *file;
GError *error = NULL;
dir = g_dir_open (path, 0, &error);
if (!dir) {
/*retval should probably be depending on error, but since we ignore it... */
GST_DEBUG ("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);
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_1_0");
if (plugin_path == NULL)
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, PyUnicode_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_1_0");
if (plugin_path == NULL)
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_API_VERSION, "plugins", "python", NULL);
PyList_Insert (sys_path, 0, PyUnicode_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, PyUnicode_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);
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, PyUnicode_FromString (sysdir));
gst_python_load_directory (plugin, sysdir);
g_free (sysdir);
}
g_strfreev (list);
}
return ret;
}
static gboolean
plugin_init (GstPlugin * plugin)
{
PyGILState_STATE state = 0;
PyObject *gi, *require_version, *args, *gst, *dict, *pyplugin;
gboolean we_initialized = FALSE;
gpointer has_python = NULL;
const gchar *override_path;
GST_DEBUG_CATEGORY_INIT (pyplugindebug, "pyplugin", 0,
"Python plugin loader");
gst_plugin_add_dependency_simple (plugin,
"HOME/.gstreamer-" GST_API_VERSION
"/plugins/python:GST_PLUGIN_SYSTEM_PATH/python:GST_PLUGIN_PATH/python",
PLUGINDIR "/python:HOME/.gstreamer-" GST_API_VERSION "/plugins/python:"
"GST_PLUGIN_SYSTEM_PATH/python:GST_PLUGIN_PATH/python", NULL,
GST_PLUGIN_DEPENDENCY_FLAG_NONE);
GST_LOG ("Checking to see if libpython is already loaded");
if (gstpy_module_symbol (gstpy_module_open (NULL),
"_Py_NoneStruct", &has_python) && has_python) {
GST_LOG ("libpython is already loaded");
} else {
GST_LOG ("loading libpython by name: %s", PY_LIB_FNAME);
if (!gstpy_module_open (PY_LIB_FNAME)) {
GST_ERROR ("Couldn't load libpython. Reason: %s", gstpy_module_error ());
return FALSE;
}
}
if (!Py_IsInitialized ()) {
GST_LOG ("python wasn't already initialized");
/* set the correct plugin for registering stuff */
Py_Initialize ();
we_initialized = TRUE;
} else {
GST_LOG ("python was already initialized");
state = PyGILState_Ensure ();
}
if ((override_path = g_getenv ("GST_OVERRIDE_SRC_PATH"))) {
gchar *overrides_setup =
g_build_filename (override_path, "..", "..", "testsuite",
"overrides_hack.py", NULL);
FILE *fd = fopen (overrides_setup, "rb");
if (!fd || PyRun_SimpleFileExFlags (fd, overrides_setup, 1, 0)) {
g_free (overrides_setup);
return FALSE;
} else {
g_free (overrides_setup);
GST_INFO ("Imported overrides setup");
}
}
GST_LOG ("Running with python version '%s'", Py_GetVersion ());
GST_LOG ("initializing pygobject");
if (!pygobject_init (3, 0, 0)) {
if (PyErr_Occurred ()) {
PyObject *type, *value, *traceback;
PyErr_Fetch (&type, &value, &traceback);
PyObject *str = PyObject_Str (value);
if (str) {
g_critical ("pygobject initialization failed: %s\n",
PyUnicode_AsUTF8 (str));
Py_DECREF (str);
}
Py_XDECREF (type);
Py_XDECREF (value);
Py_XDECREF (traceback);
PyErr_Clear ();
}
return FALSE;
}
gi = PyImport_ImportModule ("gi");
if (!gi) {
g_critical ("can't find gi");
return FALSE;
}
require_version = PyObject_GetAttrString (gi, (char *) "require_version");
args = PyTuple_Pack (2, PyUnicode_FromString ("Gst"),
PyUnicode_FromString ("1.0"));
PyObject_CallObject (require_version, args);
Py_DECREF (require_version);
Py_DECREF (args);
Py_DECREF (gi);
gst = PyImport_ImportModule ("gi.repository.Gst");
if (!gst) {
g_critical ("can't find gi.repository.Gst");
return FALSE;
}
if (we_initialized) {
PyObject *tmp;
dict = PyModule_GetDict (gst);
if (!dict) {
g_critical ("gi.repository.Gst is no dict");
return FALSE;
}
tmp =
PyObject_GetAttr (PyMapping_GetItemString (dict,
"_introspection_module"), PyUnicode_FromString ("__dict__"));
_PyGstElement_Type = PyMapping_GetItemString (tmp, "Element");
if (!_PyGstElement_Type) {
g_critical ("Could not get Gst.Element");
return FALSE;
}
pyplugin = pygobject_new (G_OBJECT (plugin));
if (!pyplugin || PyModule_AddObject (gst, "__plugin__", pyplugin) != 0) {
g_critical ("Couldn't set __plugin__ attribute");
if (pyplugin)
Py_DECREF (pyplugin);
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
PyGILState_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)