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/* GStreamer
* Copyright (C) 2016 Stefan Sauer <>
* gsttracerrecord.c: tracer log record class
* 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
* 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:gsttracerrecord
* @short_description: Trace log entry class
* Tracing modules will create instances of this class to announce the data they
* will log and create a log formatter.
* Since: 1.8
#include "gst_private.h"
#include "gstenumtypes.h"
#include "gstinfo.h"
#include "gststructure.h"
#include "gsttracerrecord.h"
#include "gstvalue.h"
#include <gobject/gvaluecollector.h>
#define GST_CAT_DEFAULT tracer_debug
struct _GstTracerRecord
GstObject parent;
GstStructure *spec;
gchar *format;
struct _GstTracerRecordClass
GstObjectClass parent_class;
#define gst_tracer_record_parent_class parent_class
G_DEFINE_TYPE (GstTracerRecord, gst_tracer_record, GST_TYPE_OBJECT);
static gboolean
build_field_template (GQuark field_id, const GValue * value, gpointer user_data)
GString *s = (GString *) user_data;
const GstStructure *sub;
GValue template_value = { 0, };
GType type = G_TYPE_INVALID;
GstTracerValueFlags flags = GST_TRACER_VALUE_FLAGS_NONE;
gboolean res;
GST_WARNING ("expected field of type GstStructure, but %s is %s",
g_quark_to_string (field_id), G_VALUE_TYPE_NAME (value));
return FALSE;
sub = gst_value_get_structure (value);
gst_structure_get (sub, "type", G_TYPE_GTYPE, &type, "flags",
gchar *opt_name = g_strconcat ("have-", g_quark_to_string (field_id), NULL);
/* add a boolean field, that indicates the presence of the next field */
g_value_init (&template_value, G_TYPE_BOOLEAN);
priv__gst_structure_append_template_to_gstring (g_quark_from_string
(opt_name), &template_value, s);
g_value_unset (&template_value);
g_free (opt_name);
g_value_init (&template_value, type);
res = priv__gst_structure_append_template_to_gstring (field_id,
&template_value, s);
g_value_unset (&template_value);
return res;
static void
gst_tracer_record_build_format (GstTracerRecord * self)
GstStructure *structure = self->spec;
GString *s;
gchar *name = (gchar *) g_quark_to_string (structure->name);
gchar *p;
g_return_if_fail (g_str_has_suffix (name, ".class"));
/* announce the format */
GST_TRACE ("%" GST_PTR_FORMAT, structure);
/* cut off '.class' suffix */
name = g_strdup (name);
p = strrchr (name, '.');
g_assert (p != NULL);
*p = '\0';
s = g_string_sized_new (STRUCTURE_ESTIMATED_STRING_LEN (structure));
g_string_append (s, name);
gst_structure_foreach (structure, build_field_template, s);
g_string_append_c (s, ';');
self->format = g_string_free (s, FALSE);
GST_DEBUG ("new format string: %s", self->format);
g_free (name);
static void
gst_tracer_record_dispose (GObject * object)
GstTracerRecord *self = GST_TRACER_RECORD (object);
if (self->spec) {
gst_structure_free (self->spec);
self->spec = NULL;
g_free (self->format);
self->format = NULL;
static void
gst_tracer_record_class_init (GstTracerRecordClass * klass)
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->dispose = gst_tracer_record_dispose;
static void
gst_tracer_record_init (GstTracerRecord * self)
* gst_tracer_record_new:
* @name: name of new record, must end on ".class".
* @firstfield: name of first field to set
* @...: additional arguments
* Create a new tracer record. The record instance can be used to efficiently
* log entries using gst_tracer_record_log().
* The @name without the ".class" suffix will be used for the log records.
* There must be fields for each value that gets logged where the field name is
* the value name. The field must be a #GstStructure describing the value. The
* sub structure must contain a field called 'type' of %G_TYPE_GTYPE that
* contains the GType of the value. The resulting #GstTracerRecord will take
* ownership of the field structures.
* The way to deal with optional values is to log an additional boolean before
* the optional field, that if %TRUE signals that the optional field is valid
* and %FALSE signals that the optional field should be ignored. One must still
* log a placeholder value for the optional field though. Please also note, that
* pointer type values must not be NULL - the underlying serialisation can not
* handle that right now.
* <note><para>
* Please note that this is still under discussion and subject to change.
* </para></note>
* Returns: a new #GstTracerRecord
GstTracerRecord *
gst_tracer_record_new (const gchar * name, const gchar * firstfield, ...)
GstTracerRecord *self;
GstStructure *structure;
va_list varargs;
gchar *err = NULL;
GType type;
GQuark id;
va_start (varargs, firstfield);
structure = gst_structure_new_empty (name);
while (firstfield) {
GValue val = { 0, };
id = g_quark_from_string (firstfield);
type = va_arg (varargs, GType);
/* all fields passed here must be GstStructures which we take over */
if (type != GST_TYPE_STRUCTURE) {
GST_WARNING ("expected field of type GstStructure, but %s is %s",
firstfield, g_type_name (type));
G_VALUE_COLLECT_INIT (&val, type, varargs, G_VALUE_NOCOPY_CONTENTS, &err);
if (G_UNLIKELY (err)) {
g_critical ("%s", err);
/* see boxed_proxy_collect_value */[1].v_uint &= ~G_VALUE_NOCOPY_CONTENTS;
gst_structure_id_take_value (structure, id, &val);
firstfield = va_arg (varargs, gchar *);
va_end (varargs);
self = g_object_newv (GST_TYPE_TRACER_RECORD, 0, NULL);
self->spec = structure;
gst_tracer_record_build_format (self);
return self;
* gst_tracer_record_log:
* @self: the tracer-record
* @...: the args as described in the spec-
* Serialzes the trace event into the log.
* Right now this is using the gstreamer debug log with the level TRACE (7) and
* the category "GST_TRACER".
* <note><para>
* Please note that this is still under discussion and subject to change.
* </para></note>
gst_tracer_record_log (GstTracerRecord * self, ...)
va_list var_args;
* does it make sense to use the {file, line, func} from the tracer hook?
* a)
* - we'd need to pass them in the macros to gst_tracer_dispatch()
* - and each tracer needs to grab them from the va_list and pass them here
* b)
* - we create a context in dispatch, pass that to the tracer
* - and the tracer will pass that here
* ideally we also use *our* ts instead of the one that
* gst_debug_log_default() will pick
va_start (var_args, self);
if (G_LIKELY (GST_LEVEL_TRACE <= _gst_debug_min)) {
gst_debug_log_valist (GST_CAT_DEFAULT, GST_LEVEL_TRACE, "", "", 0, NULL,
self->format, var_args);
va_end (var_args);