gstreamer/gst/gsttracerutils.c
Olivier Crête 8332b44a2a tracers: Add tracepoint when a plugin feature it loaded
This makes it possible to trace which ones are loaded in a specific
program to make nice statistics.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/782>
2021-08-18 17:01:27 -04:00

250 lines
7.5 KiB
C

/* GStreamer
* Copyright (C) 2013 Stefan Sauer <ensonic@users.sf.net>
*
* gsttracerutils.c: tracing subsystem
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/* Tracing subsystem:
*
* The tracing subsystem provides hooks in the core library and API for modules
* to attach to them.
*
* The user can activate tracers by setting the environment variable GST_TRACE
* to a ';' separated list of tracers.
*
* Note that instantiating tracers at runtime is possible but is not thread safe
* and needs to be done before any pipeline state is set to PAUSED.
*/
#include "gst_private.h"
#include "gsttracer.h"
#include "gsttracerfactory.h"
#include "gsttracerutils.h"
#ifndef GST_DISABLE_GST_TRACER_HOOKS
/* tracer quarks */
/* These strings must match order and number declared in the GstTracerQuarkId
* enum in gsttracerutils.h! */
static const gchar *_quark_strings[] = {
"pad-push-pre", "pad-push-post", "pad-push-list-pre", "pad-push-list-post",
"pad-pull-range-pre", "pad-pull-range-post", "pad-push-event-pre",
"pad-push-event-post", "pad-query-pre", "pad-query-post",
"element-post-message-pre",
"element-post-message-post", "element-query-pre", "element-query-post",
"element-new", "element-add-pad", "element-remove-pad",
"bin-add-pre", "bin-add-post", "bin-remove-pre", "bin-remove-post",
"pad-link-pre", "pad-link-post", "pad-unlink-pre", "pad-unlink-post",
"element-change-state-pre", "element-change-state-post",
"mini-object-created", "mini-object-destroyed", "object-created",
"object-destroyed", "mini-object-reffed", "mini-object-unreffed",
"object-reffed", "object-unreffed", "plugin-feature-loaded"
};
GQuark _priv_gst_tracer_quark_table[GST_TRACER_QUARK_MAX];
/* tracing helpers */
gboolean _priv_tracer_enabled = FALSE;
GHashTable *_priv_tracers = NULL;
/* Initialize the tracing system */
void
_priv_gst_tracing_init (void)
{
gint i = 0;
const gchar *env = g_getenv ("GST_TRACERS");
/* We initialize the tracer sub system even if the end
* user did not activate it through the env variable
* so that external tools can use it anyway */
GST_DEBUG ("Initializing GstTracer");
_priv_tracers = g_hash_table_new (NULL, NULL);
if (G_N_ELEMENTS (_quark_strings) != GST_TRACER_QUARK_MAX)
g_warning ("the quark table is not consistent! %d != %d",
(gint) G_N_ELEMENTS (_quark_strings), GST_TRACER_QUARK_MAX);
for (i = 0; i < GST_TRACER_QUARK_MAX; i++) {
_priv_gst_tracer_quark_table[i] =
g_quark_from_static_string (_quark_strings[i]);
}
if (env != NULL && *env != '\0') {
GstRegistry *registry = gst_registry_get ();
GstPluginFeature *feature;
GstTracerFactory *factory;
gchar **t = g_strsplit_set (env, ";", 0);
gchar *params;
GST_INFO ("enabling tracers: '%s'", env);
i = 0;
while (t[i]) {
// check t[i] for params
if ((params = strchr (t[i], '('))) {
gchar *end = strchr (&params[1], ')');
*params = '\0';
params++;
if (end)
*end = '\0';
} else {
params = NULL;
}
GST_INFO ("checking tracer: '%s'", t[i]);
if ((feature = gst_registry_lookup_feature (registry, t[i]))) {
factory = GST_TRACER_FACTORY (gst_plugin_feature_load (feature));
if (factory) {
GstTracer *tracer;
GST_INFO_OBJECT (factory, "creating tracer: type-id=%u",
(guint) factory->type);
tracer = g_object_new (factory->type, "params", params, NULL);
/* Clear floating flag */
gst_object_ref_sink (tracer);
/* tracers register them self to the hooks */
gst_object_unref (tracer);
} else {
GST_WARNING_OBJECT (feature,
"loading plugin containing feature %s failed!", t[i]);
}
} else {
GST_WARNING ("no tracer named '%s'", t[i]);
}
i++;
}
g_strfreev (t);
}
}
void
_priv_gst_tracing_deinit (void)
{
GList *h_list, *h_node, *t_node;
GstTracerHook *hook;
_priv_tracer_enabled = FALSE;
if (!_priv_tracers)
return;
/* shutdown tracers for final reports */
h_list = g_hash_table_get_values (_priv_tracers);
for (h_node = h_list; h_node; h_node = g_list_next (h_node)) {
for (t_node = h_node->data; t_node; t_node = g_list_next (t_node)) {
hook = (GstTracerHook *) t_node->data;
gst_object_unref (hook->tracer);
g_slice_free (GstTracerHook, hook);
}
g_list_free (h_node->data);
}
g_list_free (h_list);
g_hash_table_destroy (_priv_tracers);
_priv_tracers = NULL;
}
static void
gst_tracing_register_hook_id (GstTracer * tracer, GQuark detail, GCallback func)
{
gpointer key = GINT_TO_POINTER (detail);
GList *list = g_hash_table_lookup (_priv_tracers, key);
GstTracerHook *hook = g_slice_new0 (GstTracerHook);
hook->tracer = gst_object_ref (tracer);
hook->func = func;
list = g_list_prepend (list, hook);
g_hash_table_replace (_priv_tracers, key, list);
GST_DEBUG ("registering tracer for '%s', list.len=%d",
(detail ? g_quark_to_string (detail) : "*"), g_list_length (list));
_priv_tracer_enabled = TRUE;
}
/**
* gst_tracing_register_hook:
* @tracer: the tracer
* @detail: the detailed hook
* @func: (scope async): the callback
*
* Register @func to be called when the trace hook @detail is getting invoked.
* Use %NULL for @detail to register to all hooks.
*
* Since: 1.8
*/
void
gst_tracing_register_hook (GstTracer * tracer, const gchar * detail,
GCallback func)
{
gst_tracing_register_hook_id (tracer, g_quark_try_string (detail), func);
}
/**
* gst_tracing_get_active_tracers:
*
* Get a list of all active tracer objects owned by the tracing framework for
* the entirety of the run-time of the process or till gst_deinit() is called.
*
* Returns: (transfer full) (element-type Gst.Tracer): A #GList of
* #GstTracer objects
*
* Since: 1.18
*/
GList *
gst_tracing_get_active_tracers (void)
{
GList *tracers, *h_list, *h_node, *t_node;
GstTracerHook *hook;
if (!_priv_tracer_enabled || !_priv_tracers)
return NULL;
tracers = NULL;
h_list = g_hash_table_get_values (_priv_tracers);
for (h_node = h_list; h_node; h_node = g_list_next (h_node)) {
for (t_node = h_node->data; t_node; t_node = g_list_next (t_node)) {
hook = (GstTracerHook *) t_node->data;
/* Skip duplicate tracers from different hooks. This function is O(n), but
* that should be fine since the number of tracers enabled on a process
* should be small. */
if (g_list_index (tracers, hook->tracer) >= 0)
continue;
tracers = g_list_prepend (tracers, gst_object_ref (hook->tracer));
}
}
g_list_free (h_list);
return tracers;
}
#else /* !GST_DISABLE_GST_TRACER_HOOKS */
void
gst_tracing_register_hook (GstTracer * tracer, const gchar * detail,
GCallback func)
{
}
GList *
gst_tracing_get_active_tracers (void)
{
return NULL;
}
#endif /* GST_DISABLE_GST_TRACER_HOOKS */