/* 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 instanciating tracers at runtime is possible but is not thread safe

 * and needs to be done before any pipeline state is set to PAUSED.

 */

#define GST_USE_UNSTABLE_API

#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",

};

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.

 */

void

gst_tracing_register_hook (GstTracer * tracer, const gchar * detail,

    GCallback func)

{

  gst_tracing_register_hook_id (tracer, g_quark_try_string (detail), func);

}

#else /* !GST_DISABLE_GST_TRACER_HOOKS */

void

gst_tracing_register_hook (GstTracer * tracer, const gchar * detail,

    GCallback func)

{

}

#endif /* GST_DISABLE_GST_TRACER_HOOKS */