tracer: split into tracer and tracerutils

Keep tracer base class in tracer and move core support into the utils module.
Add a unstable-api guard to the tracer.h so that external modules would need to
acknowledge the status by setting GST_USE_UNSTABLE_API.

17 files changed, 403 insertions, 325 deletions

diff --git a/gst/Makefile.am b/gst/Makefile.am
index 68203da52..1fadb97e4 100644
--- a/gst/Makefile.am
+++ b/gst/Makefile.am
@@ -117,6 +117,7 @@ libgstreamer_@GST_API_VERSION@_la_SOURCES = \
 	$(GST_TRACE_SRC)	\
 	gsttracer.c		\
 	gsttracerfactory.c	\
+	gsttracerutils.c		\
 	gsttypefind.c		\
 	gsttypefindfactory.c	\
 	gsturi.c		\
@@ -221,6 +222,7 @@ gst_headers =			\
 	gsttocsetter.h		\
 	gsttracer.h		\
 	gsttracerfactory.h	\
+	gsttracerutils.h		\
 	gsttypefind.h		\
 	gsttypefindfactory.h	\
 	gsturi.h		\
diff --git a/gst/gst.h b/gst/gst.h
index c9ffed55b..a9c7dc4b7 100644
--- a/gst/gst.h
+++ b/gst/gst.h
@@ -77,7 +77,6 @@
 #include <gst/gsttaskpool.h>
 #include <gst/gsttoc.h>
 #include <gst/gsttocsetter.h>
-#include <gst/gsttracer.h>
 #include <gst/gsttracerfactory.h>
 #include <gst/gsttypefind.h>
 #include <gst/gsttypefindfactory.h>
diff --git a/gst/gst_private.h b/gst/gst_private.h
index 39e224587..384dc7b43 100644
--- a/gst/gst_private.h
+++ b/gst/gst_private.h
@@ -62,6 +62,8 @@ extern const char             g_log_domain_gstreamer[];
 
 #include "gstdatetime.h"
 
+#include "gsttracerutils.h"
+
 G_BEGIN_DECLS
 
 /* used by gstparse.c and grammar.y */
diff --git a/gst/gstelement.c b/gst/gstelement.c
index bed709bdc..e6d1e3d8c 100644
--- a/gst/gstelement.c
+++ b/gst/gstelement.c
@@ -90,7 +90,7 @@
 #include "gstutils.h"
 #include "gstinfo.h"
 #include "gstquark.h"
-#include "gsttracer.h"
+#include "gsttracerutils.h"
 #include "gstvalue.h"
 #include "gst-i18n-lib.h"
 #include "glib-compat-private.h"
diff --git a/gst/gstpad.c b/gst/gstpad.c
index 5c4ad4485..5ba5b3253 100644
--- a/gst/gstpad.c
+++ b/gst/gstpad.c
@@ -94,7 +94,7 @@
 #include "gstutils.h"
 #include "gstinfo.h"
 #include "gsterror.h"
-#include "gsttracer.h"
+#include "gsttracerutils.h"
 #include "gstvalue.h"
 #include "glib-compat-private.h"
 
diff --git a/gst/gstregistrychunks.c b/gst/gstregistrychunks.c
index c88152d12..7712fcf60 100644
--- a/gst/gstregistrychunks.c
+++ b/gst/gstregistrychunks.c
@@ -31,7 +31,6 @@
 #include <gst/gst_private.h>
 #include <gst/gstconfig.h>
 #include <gst/gstelement.h>
-#include <gst/gsttracer.h>
 #include <gst/gsttracerfactory.h>
 #include <gst/gsttypefind.h>
 #include <gst/gsttypefindfactory.h>
diff --git a/gst/gsttracer.c b/gst/gsttracer.c
index 065ca3abb..42ec2b66c 100644
--- a/gst/gsttracer.c
+++ b/gst/gsttracer.c
@@ -1,7 +1,7 @@
 /* GStreamer
  * Copyright (C) 2013 Stefan Sauer <ensonic@users.sf.net>
  *
- * gsttracer.h: tracing subsystem
+ * gsttracer.c: tracer base class
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ -21,28 +21,20 @@
 
 /**
  * SECTION:gsttracer
- * @short_description: Tracing subsystem
- *
- * The tracing subsystem provides hooks in the core library and API for modules
- * to attach to them.
+ * @short_description: Tracing base class
  *
  * Tracing modules will subclass #GstTracer and register through
  * gst_tracer_register(). Modules can attach to various hook-types - see
  * #GstTracerHook. When invoked they receive hook specific contextual data, 
  * which they must not modify.
- *
- * The user can activate tracers by setting the environment variable GST_TRACE
- * to a ';' separated list of tracers.
  */
 
+#define GST_USE_UNSTABLE_API
+
 #include "gst_private.h"
 #include "gstenumtypes.h"
-#include "gstregistry.h"
 #include "gsttracer.h"
 #include "gsttracerfactory.h"
-#include "gstutils.h"
-
-#ifndef GST_DISABLE_GST_DEBUG
 
 GST_DEBUG_CATEGORY_EXTERN (tracer_debug);
 #define GST_CAT_DEFAULT tracer_debug
@@ -138,7 +130,7 @@ gst_tracer_get_property (GObject * object, guint prop_id,
   }
 }
 
-static void
+void
 gst_tracer_invoke (GstTracer * self, GstTracerHookId hid,
     GstTracerMessageId mid, va_list var_args)
 {
@@ -206,115 +198,6 @@ gst_tracer_register (GstPlugin * plugin, const gchar * name, GType type)
   return TRUE;
 }
 
-/* tracing helpers */
-
-gboolean _priv_tracer_enabled = FALSE;
-/* TODO(ensonic): use GPtrArray ? */
-GList *_priv_tracers[GST_TRACER_HOOK_ID_LAST] = { NULL, };
-
-/* Initialize the debugging system */
-void
-_priv_gst_tracer_init (void)
-{
-  const gchar *env = g_getenv ("GST_TRACE");
-
-  if (env != NULL && *env != '\0') {
-    GstRegistry *registry = gst_registry_get ();
-    GstPluginFeature *feature;
-    GstTracerFactory *factory;
-    GstTracerHook mask;
-    GstTracer *tracer;
-    gchar **t = g_strsplit_set (env, ";", 0);
-    gint i = 0, j;
-    gchar *params;
-
-    GST_INFO ("enabling tracers: '%s'", env);
-
-    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) {
-          GST_INFO_OBJECT (factory, "creating tracer: type-id=%u",
-              (guint) factory->type);
-
-          tracer = g_object_new (factory->type, "params", params, NULL);
-          g_object_get (tracer, "mask", &mask, NULL);
-
-          if (mask) {
-            /* add to lists according to mask */
-            j = 0;
-            while (mask && (j < GST_TRACER_HOOK_ID_LAST)) {
-              if (mask & 1) {
-                _priv_tracers[j] = g_list_prepend (_priv_tracers[j],
-                    gst_object_ref (tracer));
-                GST_WARNING_OBJECT (tracer, "added tracer to hook %d", j);
-              }
-              mask >>= 1;
-              j++;
-            }
-
-            _priv_tracer_enabled = TRUE;
-          } else {
-            GST_WARNING_OBJECT (tracer,
-                "tracer with zero mask won't have any effect");
-          }
-          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_tracer_deinit (void)
-{
-  gint i;
-  GList *node;
-
-  /* shutdown tracers for final reports */
-  for (i = 0; i < GST_TRACER_HOOK_ID_LAST; i++) {
-    for (node = _priv_tracers[i]; node; node = g_list_next (node)) {
-      gst_object_unref (node->data);
-    }
-    g_list_free (_priv_tracers[i]);
-    _priv_tracers[i] = NULL;
-  }
-  _priv_tracer_enabled = FALSE;
-}
-
-void
-gst_tracer_dispatch (GstTracerHookId hid, GstTracerMessageId mid, ...)
-{
-  va_list var_args;
-  GList *node;
-
-  for (node = _priv_tracers[hid]; node; node = g_list_next (node)) {
-    va_start (var_args, mid);
-    gst_tracer_invoke (node->data, hid, mid, var_args);
-    va_end (var_args);
-  }
-}
-
 /* tracing module helpers */
 
 void
@@ -328,5 +211,3 @@ gst_tracer_log_trace (GstStructure * s)
   g_free (data);
   gst_structure_free (s);
 }
-
-#endif /* GST_DISABLE_GST_DEBUG */
diff --git a/gst/gsttracer.h b/gst/gsttracer.h
index 99f1982de..02e2ec0a1 100644
--- a/gst/gsttracer.h
+++ b/gst/gsttracer.h
@@ -1,7 +1,7 @@
 /* GStreamer
  * Copyright (C) 2013 Stefan Sauer <ensonic@users.sf.net>
  *
- * gsttracer.h: tracing subsystem
+ * gsttracer.h: tracer base class
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ -22,63 +22,18 @@
 #ifndef __GST_TRACER_H__
 #define __GST_TRACER_H__
 
+#ifndef GST_USE_UNSTABLE_API
+#warning "The tracer subsystem is unstable API and may change in future."
+#warning "You can define GST_USE_UNSTABLE_API to avoid this warning."
+#endif
+
 #include <glib.h>
 #include <glib-object.h>
 #include <gst/gstconfig.h>
-#include <gst/gstbin.h>
+#include <gst/gsttracerutils.h>
 
 G_BEGIN_DECLS
 
-#ifndef GST_DISABLE_GST_DEBUG
-
-/* hook flags and ids */
-
-typedef enum
-{
-  GST_TRACER_HOOK_NONE      = 0,
-  GST_TRACER_HOOK_BUFFERS   = (1 << 0),
-  GST_TRACER_HOOK_EVENTS    = (1 << 1),
-  GST_TRACER_HOOK_MESSAGES  = (1 << 2),
-  GST_TRACER_HOOK_QUERIES   = (1 << 3),
-  GST_TRACER_HOOK_TOPOLOGY  = (1 << 4),
-  /*
-  GST_TRACER_HOOK_TIMER
-  */
-  GST_TRACER_HOOK_ALL       = (1 << 5) - 1
-} GstTracerHook;
-
-typedef enum
-{
-  GST_TRACER_HOOK_ID_BUFFERS = 0,
-  GST_TRACER_HOOK_ID_EVENTS,
-  GST_TRACER_HOOK_ID_MESSAGES,
-  GST_TRACER_HOOK_ID_QUERIES,
-  GST_TRACER_HOOK_ID_TOPLOGY,
-  /*
-  GST_TRACER_HOOK_ID_TIMER
-  */
-  GST_TRACER_HOOK_ID_LAST
-} GstTracerHookId;
-
-typedef enum
-{
-  GST_TRACER_MESSAGE_ID_PAD_PUSH_PRE = 0,
-  GST_TRACER_MESSAGE_ID_PAD_PUSH_POST,
-  GST_TRACER_MESSAGE_ID_PAD_PUSH_LIST_PRE,
-  GST_TRACER_MESSAGE_ID_PAD_PUSH_LIST_POST,
-  GST_TRACER_MESSAGE_ID_PAD_PULL_RANGE_PRE,
-  GST_TRACER_MESSAGE_ID_PAD_PULL_RANGE_POST,
-  GST_TRACER_MESSAGE_ID_PAD_PUSH_EVENT_PRE,
-  GST_TRACER_MESSAGE_ID_PAD_PUSH_EVENT_POST,
-  GST_TRACER_MESSAGE_ID_ELEMENT_POST_MESSAGE_PRE,
-  GST_TRACER_MESSAGE_ID_ELEMENT_POST_MESSAGE_POST,
-  GST_TRACER_MESSAGE_ID_ELEMENT_QUERY_PRE,
-  GST_TRACER_MESSAGE_ID_ELEMENT_QUERY_POST,
-  GST_TRACER_MESSAGE_ID_LAST
-} GstTracerMessageId;
-
-/* tracing plugins */
-
 typedef struct _GstTracer GstTracer;
 typedef struct _GstTracerPrivate GstTracerPrivate;
 typedef struct _GstTracerClass GstTracerClass;
@@ -111,149 +66,10 @@ struct _GstTracerClass {
   gpointer _gst_reserved[GST_PADDING];
 };
 
-GType gst_tracer_get_type          (void);
-
-/* tracing hooks */
-
-void _priv_gst_tracer_init (void);
-void _priv_gst_tracer_deinit (void);
-
-/* tracing modules */
-
-gboolean gst_tracer_register (GstPlugin * plugin, const gchar * name, GType type);
-
-/* tracing helpers */
-
-void gst_tracer_dispatch (GstTracerHookId hid, GstTracerMessageId mid, ...);
-
-/* tracing module helpers */
-
-void gst_tracer_log_trace (GstStructure * s);
-
-extern gboolean _priv_tracer_enabled;
-extern GList *_priv_tracers[GST_TRACER_HOOK_ID_LAST];
-
-extern GstClockTime _priv_gst_info_start_time;
-#define GST_TRACER_IS_ENABLED(id) \
-  (_priv_tracer_enabled && (_priv_tracers[id] != NULL))
-
-#define GST_TRACER_TS \
-  GST_CLOCK_DIFF (_priv_gst_info_start_time, gst_util_get_timestamp ())
-
-/* tracing hooks */
-
-#define GST_TRACER_PAD_PUSH_PRE(pad, buffer) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
-        GST_TRACER_MESSAGE_ID_PAD_PUSH_PRE, GST_TRACER_TS, \
-        pad, buffer); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_PAD_PUSH_POST(pad, res) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
-        GST_TRACER_MESSAGE_ID_PAD_PUSH_POST, GST_TRACER_TS, \
-        pad, res); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_PAD_PUSH_LIST_PRE(pad, list) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
-        GST_TRACER_MESSAGE_ID_PAD_PUSH_LIST_PRE, GST_TRACER_TS, \
-        pad, list); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_PAD_PUSH_LIST_POST(pad, res) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
-        GST_TRACER_MESSAGE_ID_PAD_PUSH_LIST_POST, GST_TRACER_TS, \
-        pad, res); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_PAD_PULL_RANGE_PRE(pad, offset, size) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
-        GST_TRACER_MESSAGE_ID_PAD_PULL_RANGE_PRE, GST_TRACER_TS, \
-        pad, offset, size); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_PAD_PULL_RANGE_POST(pad, buffer, res) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
-        GST_TRACER_MESSAGE_ID_PAD_PULL_RANGE_POST, GST_TRACER_TS, \
-        pad, buffer, res); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_PAD_PUSH_EVENT_PRE(pad, event) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_EVENTS)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_EVENTS, \
-        GST_TRACER_MESSAGE_ID_PAD_PUSH_EVENT_PRE, GST_TRACER_TS, \
-        pad, event); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_PAD_PUSH_EVENT_POST(pad, res) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_EVENTS)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_EVENTS, \
-        GST_TRACER_MESSAGE_ID_PAD_PUSH_EVENT_POST, GST_TRACER_TS, \
-        pad, res); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_ELEMENT_POST_MESSAGE_PRE(element, message) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_MESSAGES)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_MESSAGES, \
-        GST_TRACER_MESSAGE_ID_ELEMENT_POST_MESSAGE_PRE, GST_TRACER_TS, \
-        element, message); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_ELEMENT_POST_MESSAGE_POST(element, res) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_MESSAGES)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_MESSAGES, \
-        GST_TRACER_MESSAGE_ID_ELEMENT_POST_MESSAGE_POST, GST_TRACER_TS, \
-        element, res); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_ELEMENT_QUERY_PRE(element, query) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_QUERIES)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_QUERIES, \
-        GST_TRACER_MESSAGE_ID_ELEMENT_QUERY_PRE, GST_TRACER_TS, \
-        element, query); \
-  } \
-}G_STMT_END
-
-#define GST_TRACER_ELEMENT_QUERY_POST(element, res) G_STMT_START{ \
-  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_QUERIES)) { \
-    gst_tracer_dispatch (GST_TRACER_HOOK_ID_QUERIES, \
-        GST_TRACER_MESSAGE_ID_ELEMENT_QUERY_POST, GST_TRACER_TS, \
-        element, res); \
-  } \
-}G_STMT_END
-
-#else /* !GST_DISABLE_GST_DEBUG */
-
-#define GST_TRACER_PAD_PUSH_PRE(pad, buffer)
-#define GST_TRACER_PAD_PUSH_POST(pad, res)
-#define GST_TRACER_PAD_PUSH_LIST_PRE(pad, list)
-#define GST_TRACER_PAD_PUSH_LIST_POST(pad, res)
-#define GST_TRACER_PAD_PULL_RANGE_PRE(pad, offset, size)
-#define GST_TRACER_PAD_PULL_RANGE_POST(pad, buffer, res)
-#define GST_TRACER_PAD_PUSH_EVENT_PRE(pad, event)
-#define GST_TRACER_PAD_PUSH_EVENT_POST(pad, res)
-#define GST_TRACER_ELEMENT_POST_MESSAGE_PRE(element, message)
-#define GST_TRACER_ELEMENT_POST_MESSAGE_POST(element, res)
-#define GST_TRACER_ELEMENT_QUERY_PRE(element, query)
-#define GST_TRACER_ELEMENT_QUERY_POST(element, res)
+void gst_tracer_invoke (GstTracer * self, GstTracerHookId hid,
+    GstTracerMessageId mid, va_list var_args);
 
-#endif /* GST_DISABLE_GST_DEBUG */
+GType gst_tracer_get_type          (void);
 
 G_END_DECLS
 
diff --git a/gst/gsttracerfactory.c b/gst/gsttracerfactory.c
index 9cdbb86f1..ec7ba5387 100644
--- a/gst/gsttracerfactory.c
+++ b/gst/gsttracerfactory.c
@@ -29,7 +29,6 @@
 
 #include "gst_private.h"
 #include "gstinfo.h"
-#include "gsttracer.h"
 #include "gsttracerfactory.h"
 #include "gstregistry.h"
 
diff --git a/gst/gsttracerfactory.h b/gst/gsttracerfactory.h
index 2bfe481b1..8e9370c39 100644
--- a/gst/gsttracerfactory.h
+++ b/gst/gsttracerfactory.h
@@ -25,7 +25,6 @@
 #include <gst/gstcaps.h>
 #include <gst/gstplugin.h>
 #include <gst/gstpluginfeature.h>
-#include <gst/gsttracer.h>
 
 G_BEGIN_DECLS
 
diff --git a/gst/gsttracerutils.c b/gst/gsttracerutils.c
new file mode 100644
index 000000000..ed83f8290
--- /dev/null
+++ b/gst/gsttracerutils.c
@@ -0,0 +1,151 @@
+/* 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.
+ */
+
+/**
+ * SECTION:gsttracerutils
+ * @short_description: 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.
+ */
+
+#define GST_USE_UNSTABLE_API
+
+#include "gst_private.h"
+#include "gsttracer.h"
+#include "gsttracerfactory.h"
+#include "gsttracerutils.h"
+
+#ifndef GST_DISABLE_GST_DEBUG
+
+/* tracing helpers */
+
+gboolean _priv_tracer_enabled = FALSE;
+/* TODO(ensonic): use array of GPtrArray* ? */
+GList *_priv_tracers[GST_TRACER_HOOK_ID_LAST] = { NULL, };
+
+/* Initialize the tracing system */
+void
+_priv_gst_tracer_init (void)
+{
+  const gchar *env = g_getenv ("GST_TRACE");
+
+  if (env != NULL && *env != '\0') {
+    GstRegistry *registry = gst_registry_get ();
+    GstPluginFeature *feature;
+    GstTracerFactory *factory;
+    GstTracerHook mask;
+    GstObject *tracer;
+    gchar **t = g_strsplit_set (env, ";", 0);
+    gint i = 0, j;
+    gchar *params;
+
+    GST_INFO ("enabling tracers: '%s'", env);
+
+    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) {
+          GST_INFO_OBJECT (factory, "creating tracer: type-id=%u",
+              (guint) factory->type);
+
+          tracer = g_object_new (factory->type, "params", params, NULL);
+          g_object_get (tracer, "mask", &mask, NULL);
+
+          if (mask) {
+            /* add to lists according to mask */
+            j = 0;
+            while (mask && (j < GST_TRACER_HOOK_ID_LAST)) {
+              if (mask & 1) {
+                _priv_tracers[j] = g_list_prepend (_priv_tracers[j],
+                    gst_object_ref (tracer));
+                GST_WARNING_OBJECT (tracer, "added tracer to hook %d", j);
+              }
+              mask >>= 1;
+              j++;
+            }
+
+            _priv_tracer_enabled = TRUE;
+          } else {
+            GST_WARNING_OBJECT (tracer,
+                "tracer with zero mask won't have any effect");
+          }
+          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_tracer_deinit (void)
+{
+  gint i;
+  GList *node;
+
+  /* shutdown tracers for final reports */
+  for (i = 0; i < GST_TRACER_HOOK_ID_LAST; i++) {
+    for (node = _priv_tracers[i]; node; node = g_list_next (node)) {
+      gst_object_unref (node->data);
+    }
+    g_list_free (_priv_tracers[i]);
+    _priv_tracers[i] = NULL;
+  }
+  _priv_tracer_enabled = FALSE;
+}
+
+void
+gst_tracer_dispatch (GstTracerHookId hid, GstTracerMessageId mid, ...)
+{
+  va_list var_args;
+  GList *node;
+
+  for (node = _priv_tracers[hid]; node; node = g_list_next (node)) {
+    va_start (var_args, mid);
+    gst_tracer_invoke (node->data, hid, mid, var_args);
+    va_end (var_args);
+  }
+}
+
+#endif /* GST_DISABLE_GST_DEBUG */
diff --git a/gst/gsttracerutils.h b/gst/gsttracerutils.h
new file mode 100644
index 000000000..c3bd5f35a
--- /dev/null
+++ b/gst/gsttracerutils.h
@@ -0,0 +1,225 @@
+/* GStreamer
+ * Copyright (C) 2013 Stefan Sauer <ensonic@users.sf.net>
+ *
+ * gsttracerutils.h: 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.
+ */
+
+
+#ifndef __GST_TRACER_UTILS_H__
+#define __GST_TRACER_UTILS_H__
+
+#include <glib.h>
+#include <glib-object.h>
+#include <gst/gstconfig.h>
+#include <gst/gstbin.h>
+
+G_BEGIN_DECLS
+
+#ifndef GST_DISABLE_GST_DEBUG
+
+/* hook flags and ids */
+
+typedef enum
+{
+  GST_TRACER_HOOK_NONE      = 0,
+  GST_TRACER_HOOK_BUFFERS   = (1 << 0),
+  GST_TRACER_HOOK_EVENTS    = (1 << 1),
+  GST_TRACER_HOOK_MESSAGES  = (1 << 2),
+  GST_TRACER_HOOK_QUERIES   = (1 << 3),
+  GST_TRACER_HOOK_TOPOLOGY  = (1 << 4),
+  /*
+  GST_TRACER_HOOK_TIMER
+  */
+  GST_TRACER_HOOK_ALL       = (1 << 5) - 1
+} GstTracerHook;
+
+typedef enum
+{
+  GST_TRACER_HOOK_ID_BUFFERS = 0,
+  GST_TRACER_HOOK_ID_EVENTS,
+  GST_TRACER_HOOK_ID_MESSAGES,
+  GST_TRACER_HOOK_ID_QUERIES,
+  GST_TRACER_HOOK_ID_TOPLOGY,
+  /*
+  GST_TRACER_HOOK_ID_TIMER
+  */
+  GST_TRACER_HOOK_ID_LAST
+} GstTracerHookId;
+
+typedef enum
+{
+  GST_TRACER_MESSAGE_ID_PAD_PUSH_PRE = 0,
+  GST_TRACER_MESSAGE_ID_PAD_PUSH_POST,
+  GST_TRACER_MESSAGE_ID_PAD_PUSH_LIST_PRE,
+  GST_TRACER_MESSAGE_ID_PAD_PUSH_LIST_POST,
+  GST_TRACER_MESSAGE_ID_PAD_PULL_RANGE_PRE,
+  GST_TRACER_MESSAGE_ID_PAD_PULL_RANGE_POST,
+  GST_TRACER_MESSAGE_ID_PAD_PUSH_EVENT_PRE,
+  GST_TRACER_MESSAGE_ID_PAD_PUSH_EVENT_POST,
+  GST_TRACER_MESSAGE_ID_ELEMENT_POST_MESSAGE_PRE,
+  GST_TRACER_MESSAGE_ID_ELEMENT_POST_MESSAGE_POST,
+  GST_TRACER_MESSAGE_ID_ELEMENT_QUERY_PRE,
+  GST_TRACER_MESSAGE_ID_ELEMENT_QUERY_POST,
+  GST_TRACER_MESSAGE_ID_LAST
+} GstTracerMessageId;
+
+/* tracing hooks */
+
+void _priv_gst_tracer_init (void);
+void _priv_gst_tracer_deinit (void);
+
+/* tracing modules */
+
+gboolean gst_tracer_register (GstPlugin * plugin, const gchar * name, GType type);
+
+/* tracing helpers */
+
+void gst_tracer_dispatch (GstTracerHookId hid, GstTracerMessageId mid, ...);
+
+/* tracing module helpers */
+
+void gst_tracer_log_trace (GstStructure * s);
+
+extern gboolean _priv_tracer_enabled;
+extern GList *_priv_tracers[GST_TRACER_HOOK_ID_LAST];
+
+#define GST_TRACER_IS_ENABLED(id) \
+  (_priv_tracer_enabled && (_priv_tracers[id] != NULL))
+
+#define GST_TRACER_TS \
+  GST_CLOCK_DIFF (_priv_gst_info_start_time, gst_util_get_timestamp ())
+
+/* tracing hooks */
+
+#define GST_TRACER_PAD_PUSH_PRE(pad, buffer) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
+        GST_TRACER_MESSAGE_ID_PAD_PUSH_PRE, GST_TRACER_TS, \
+        pad, buffer); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_PAD_PUSH_POST(pad, res) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
+        GST_TRACER_MESSAGE_ID_PAD_PUSH_POST, GST_TRACER_TS, \
+        pad, res); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_PAD_PUSH_LIST_PRE(pad, list) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
+        GST_TRACER_MESSAGE_ID_PAD_PUSH_LIST_PRE, GST_TRACER_TS, \
+        pad, list); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_PAD_PUSH_LIST_POST(pad, res) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
+        GST_TRACER_MESSAGE_ID_PAD_PUSH_LIST_POST, GST_TRACER_TS, \
+        pad, res); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_PAD_PULL_RANGE_PRE(pad, offset, size) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
+        GST_TRACER_MESSAGE_ID_PAD_PULL_RANGE_PRE, GST_TRACER_TS, \
+        pad, offset, size); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_PAD_PULL_RANGE_POST(pad, buffer, res) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_BUFFERS)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_BUFFERS, \
+        GST_TRACER_MESSAGE_ID_PAD_PULL_RANGE_POST, GST_TRACER_TS, \
+        pad, buffer, res); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_PAD_PUSH_EVENT_PRE(pad, event) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_EVENTS)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_EVENTS, \
+        GST_TRACER_MESSAGE_ID_PAD_PUSH_EVENT_PRE, GST_TRACER_TS, \
+        pad, event); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_PAD_PUSH_EVENT_POST(pad, res) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_EVENTS)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_EVENTS, \
+        GST_TRACER_MESSAGE_ID_PAD_PUSH_EVENT_POST, GST_TRACER_TS, \
+        pad, res); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_ELEMENT_POST_MESSAGE_PRE(element, message) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_MESSAGES)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_MESSAGES, \
+        GST_TRACER_MESSAGE_ID_ELEMENT_POST_MESSAGE_PRE, GST_TRACER_TS, \
+        element, message); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_ELEMENT_POST_MESSAGE_POST(element, res) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_MESSAGES)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_MESSAGES, \
+        GST_TRACER_MESSAGE_ID_ELEMENT_POST_MESSAGE_POST, GST_TRACER_TS, \
+        element, res); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_ELEMENT_QUERY_PRE(element, query) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_QUERIES)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_QUERIES, \
+        GST_TRACER_MESSAGE_ID_ELEMENT_QUERY_PRE, GST_TRACER_TS, \
+        element, query); \
+  } \
+}G_STMT_END
+
+#define GST_TRACER_ELEMENT_QUERY_POST(element, res) G_STMT_START{ \
+  if (GST_TRACER_IS_ENABLED(GST_TRACER_HOOK_ID_QUERIES)) { \
+    gst_tracer_dispatch (GST_TRACER_HOOK_ID_QUERIES, \
+        GST_TRACER_MESSAGE_ID_ELEMENT_QUERY_POST, GST_TRACER_TS, \
+        element, res); \
+  } \
+}G_STMT_END
+
+#else /* !GST_DISABLE_GST_DEBUG */
+
+#define GST_TRACER_PAD_PUSH_PRE(pad, buffer)
+#define GST_TRACER_PAD_PUSH_POST(pad, res)
+#define GST_TRACER_PAD_PUSH_LIST_PRE(pad, list)
+#define GST_TRACER_PAD_PUSH_LIST_POST(pad, res)
+#define GST_TRACER_PAD_PULL_RANGE_PRE(pad, offset, size)
+#define GST_TRACER_PAD_PULL_RANGE_POST(pad, buffer, res)
+#define GST_TRACER_PAD_PUSH_EVENT_PRE(pad, event)
+#define GST_TRACER_PAD_PUSH_EVENT_POST(pad, res)
+#define GST_TRACER_ELEMENT_POST_MESSAGE_PRE(element, message)
+#define GST_TRACER_ELEMENT_POST_MESSAGE_POST(element, res)
+#define GST_TRACER_ELEMENT_QUERY_PRE(element, query)
+#define GST_TRACER_ELEMENT_QUERY_POST(element, res)
+
+#endif /* GST_DISABLE_GST_DEBUG */
+
+G_END_DECLS
+
+#endif /* __GST_TRACER_UTILS_H__ */
+
diff --git a/plugins/tracers/Makefile.am b/plugins/tracers/Makefile.am
index 87db74cac..07c510a77 100644
--- a/plugins/tracers/Makefile.am
+++ b/plugins/tracers/Makefile.am
@@ -15,7 +15,8 @@ libgstcoretracers_la_SOURCES = \
   gststats.c \
 	gsttracers.c
 
-libgstcoretracers_la_CFLAGS = $(GST_OBJ_CFLAGS)
+libgstcoretracers_la_CFLAGS = $(GST_OBJ_CFLAGS) \
+  -DGST_USE_UNSTABLE_API
 libgstcoretracers_la_LIBADD = \
 	$(top_builddir)/gst/printf/libgstprintf.la \
 	$(GST_OBJ_LIBS)
diff --git a/plugins/tracers/gstlatency.h b/plugins/tracers/gstlatency.h
index efcab6b6f..e23430333 100644
--- a/plugins/tracers/gstlatency.h
+++ b/plugins/tracers/gstlatency.h
@@ -23,6 +23,7 @@
 #define __GST_LATENCY_TRACER_H__
 
 #include <gst/gst.h>
+#include <gst/gsttracer.h>
 
 G_BEGIN_DECLS
 
diff --git a/plugins/tracers/gstlog.h b/plugins/tracers/gstlog.h
index 827f2aaf2..6f0dd7fdc 100644
--- a/plugins/tracers/gstlog.h
+++ b/plugins/tracers/gstlog.h
@@ -23,6 +23,7 @@
 #define __GST_LOG_TRACER_H__
 
 #include <gst/gst.h>
+#include <gst/gsttracer.h>
 
 G_BEGIN_DECLS
 
diff --git a/plugins/tracers/gstrusage.h b/plugins/tracers/gstrusage.h
index e73515df0..b13fb85ff 100644
--- a/plugins/tracers/gstrusage.h
+++ b/plugins/tracers/gstrusage.h
@@ -23,6 +23,7 @@
 #define __GST_RUSAGE_TRACER_H__
 
 #include <gst/gst.h>
+#include <gst/gsttracer.h>
 
 G_BEGIN_DECLS
 
diff --git a/plugins/tracers/gststats.h b/plugins/tracers/gststats.h
index 97ae17652..a5f2d6787 100644
--- a/plugins/tracers/gststats.h
+++ b/plugins/tracers/gststats.h
@@ -23,6 +23,7 @@
 #define __GST_STATS_TRACER_H__
 
 #include <gst/gst.h>
+#include <gst/gsttracer.h>
 
 G_BEGIN_DECLS