gstreamer/gst/gstinfo.c

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
 *                    2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
 *
 * gstinfo.c: debugging functions
 *
 * 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.
 */

/**
 * SECTION:gstinfo
 * @short_description: Debugging and logging facillities
 * @see_also: #GstConfig, #Gst for command line parameters
 * and environment variables that affect the debugging output.
 *
 * GStreamer's debugging subsystem is an easy way to get information about what
 * the application is doing.  It is not meant for programming errors. Use GLib
 * methods (g_warning and friends) for that.
 *
 * The debugging subsystem works only after GStreamer has been initialized
 * - for example by calling gst_init().
 *
 * The debugging subsystem is used to log informational messages while the
 * application runs.  Each messages has some properties attached to it. Among
 * these properties are the debugging category, the severity (called "level"
 * here) and an optional #GObject it belongs to. Each of these messages is sent
 * to all registered debugging handlers, which then handle the messages.
 * GStreamer attaches a default handler on startup, which outputs requested
 * messages to stderr.
 *
 * Messages are output by using shortcut macros like #GST_DEBUG,
 * #GST_CAT_ERROR_OBJECT or similar. These all expand to calling gst_debug_log()
 * with the right parameters.
 * The only thing a developer will probably want to do is define his own
 * categories. This is easily done with 3 lines. At the top of your code,
 * declare
 * the variables and set the default category.
 * <informalexample>
 * <programlisting>
 * GST_DEBUG_CATEGORY_STATIC (my_category);     // define category (statically)
 * &hash;define GST_CAT_DEFAULT my_category     // set as default
 * </programlisting>
 * </informalexample>
 * After that you only need to initialize the category.
 * <informalexample>
 * <programlisting>
 * GST_DEBUG_CATEGORY_INIT (my_category, "my category",
 *                          0, "This is my very own");
 * </programlisting>
 * </informalexample>
 * Initialization must be done before the category is used first.
 * Plugins do this
 * in their plugin_init function, libraries and applications should do that
 * during their initialization.
 *
 * The whole debugging subsystem can be disabled at build time with passing the
 * --disable-gst-debug switch to configure. If this is done, every function,
 * macro and even structs described in this file evaluate to default values or
 * nothing at all.
 * So don't take addresses of these functions or use other tricks.
 * If you must do that for some reason, there is still an option.
 * If the debugging
 * subsystem was compiled out, #GST_DISABLE_GST_DEBUG is defined in
 * &lt;gst/gst.h&gt;,
 * so you can check that before doing your trick.
 * Disabling the debugging subsystem will give you a slight (read: unnoticable)
 * speed increase and will reduce the size of your compiled code. The GStreamer
 * library itself becomes around 10% smaller.
 *
 * Please note that there are naming conventions for the names of debugging
 * categories. These are explained at GST_DEBUG_CATEGORY_INIT().
 */

#include "gst_private.h"
#include "gstinfo.h"

#ifndef GST_DISABLE_GST_DEBUG

#ifdef HAVE_DLFCN_H
#  include <dlfcn.h>
#endif
#ifdef HAVE_PRINTF_EXTENSION
#  include <printf.h>
#endif
#include <stdio.h>              /* fprintf */
#ifdef HAVE_UNISTD_H
#  include <unistd.h>           /* getpid on UNIX */
#endif
#ifdef HAVE_PROCESS_H
#  include <process.h>          /* getpid on win32 */
#endif
#include <string.h>             /* G_VA_COPY */
#include "gst_private.h"
#include "gstutils.h"
#include "gstsegment.h"
#ifdef HAVE_VALGRIND
#  include <valgrind/valgrind.h>
#endif
#include <glib/gprintf.h>       /* g_sprintf */

/* underscore is to prevent conflict with GST_CAT_DEBUG define */
GST_DEBUG_CATEGORY_STATIC (_GST_CAT_DEBUG);
/* time of initialization, so we get useful debugging output times */
static GstClockTime start_time;

#if 0
#if defined __sgi__
#include <rld_interface.h>
typedef struct DL_INFO
{
  const char *dli_fname;
  void *dli_fbase;
  const char *dli_sname;
  void *dli_saddr;
  int dli_version;
  int dli_reserved1;
  long dli_reserved[4];
}
Dl_info;

#define _RLD_DLADDR             14
int dladdr (void *address, Dl_info * dl);

int
dladdr (void *address, Dl_info * dl)
{
  void *v;

  v = _rld_new_interface (_RLD_DLADDR, address, dl);
  return (int) v;
}
#endif /* __sgi__ */
#endif

static void gst_debug_reset_threshold (gpointer category, gpointer unused);
static void gst_debug_reset_all_thresholds (void);

#ifdef HAVE_PRINTF_EXTENSION
static int _gst_info_printf_extension_ptr (FILE * stream,
    const struct printf_info *info, const void *const *args);
static int _gst_info_printf_extension_segment (FILE * stream,
    const struct printf_info *info, const void *const *args);
static int _gst_info_printf_extension_arginfo (const struct printf_info *info,
    size_t n, int *argtypes);
#endif

struct _GstDebugMessage
{
  gchar *message;
  const gchar *format;
  va_list arguments;
};

/* list of all name/level pairs from --gst-debug and GST_DEBUG */
static GStaticMutex __level_name_mutex = G_STATIC_MUTEX_INIT;
static GSList *__level_name = NULL;
typedef struct
{
  GPatternSpec *pat;
  GstDebugLevel level;
}
LevelNameEntry;

/* list of all categories */
static GStaticMutex __cat_mutex = G_STATIC_MUTEX_INIT;
static GSList *__categories = NULL;

/* all registered debug handlers */
typedef struct
{
  GstLogFunction func;
  gpointer user_data;
}
LogFuncEntry;
static GStaticMutex __log_func_mutex = G_STATIC_MUTEX_INIT;
static GSList *__log_functions = NULL;

static gint __default_level;
static gint __use_color;

/* disabled by default, as soon as some threshold is set > NONE,
 * it becomes enabled. */
gboolean __gst_debug_enabled = FALSE;
GstDebugLevel __gst_debug_min = GST_LEVEL_NONE;

GstDebugCategory *GST_CAT_DEFAULT = NULL;

GstDebugCategory *GST_CAT_GST_INIT = NULL;
GstDebugCategory *GST_CAT_AUTOPLUG = NULL;
GstDebugCategory *GST_CAT_AUTOPLUG_ATTEMPT = NULL;
GstDebugCategory *GST_CAT_PARENTAGE = NULL;
GstDebugCategory *GST_CAT_STATES = NULL;
GstDebugCategory *GST_CAT_SCHEDULING = NULL;

GstDebugCategory *GST_CAT_BUFFER = NULL;
GstDebugCategory *GST_CAT_BUS = NULL;
GstDebugCategory *GST_CAT_CAPS = NULL;
GstDebugCategory *GST_CAT_CLOCK = NULL;
GstDebugCategory *GST_CAT_ELEMENT_PADS = NULL;
GstDebugCategory *GST_CAT_PADS = NULL;
GstDebugCategory *GST_CAT_PIPELINE = NULL;
GstDebugCategory *GST_CAT_PLUGIN_LOADING = NULL;
GstDebugCategory *GST_CAT_PLUGIN_INFO = NULL;
GstDebugCategory *GST_CAT_PROPERTIES = NULL;
GstDebugCategory *GST_CAT_TYPES = NULL;
GstDebugCategory *GST_CAT_XML = NULL;
GstDebugCategory *GST_CAT_NEGOTIATION = NULL;
GstDebugCategory *GST_CAT_REFCOUNTING = NULL;
GstDebugCategory *GST_CAT_ERROR_SYSTEM = NULL;
GstDebugCategory *GST_CAT_EVENT = NULL;
GstDebugCategory *GST_CAT_MESSAGE = NULL;
GstDebugCategory *GST_CAT_PARAMS = NULL;
GstDebugCategory *GST_CAT_CALL_TRACE = NULL;
GstDebugCategory *GST_CAT_SIGNAL = NULL;
GstDebugCategory *GST_CAT_PROBE = NULL;
GstDebugCategory *GST_CAT_REGISTRY = NULL;
GstDebugCategory *GST_CAT_QOS = NULL;

/* FIXME: export this? */
gboolean
__gst_in_valgrind (void)
{
  static enum
  {
    GST_VG_UNCHECKED,
    GST_VG_NO_VALGRIND,
    GST_VG_INSIDE
  }
  in_valgrind = GST_VG_UNCHECKED;

  if (in_valgrind == GST_VG_UNCHECKED) {
#ifdef HAVE_VALGRIND
    if (RUNNING_ON_VALGRIND) {
      GST_CAT_INFO (GST_CAT_GST_INIT, "we're running inside valgrind");
      printf ("GStreamer has detected that it is running inside valgrind.\n");
      printf ("It might now take different code paths to ease debugging.\n");
      printf ("Of course, this may also lead to different bugs.\n");
      in_valgrind = GST_VG_INSIDE;
    } else {
      GST_CAT_LOG (GST_CAT_GST_INIT, "not doing extra valgrind stuff");
      in_valgrind = GST_VG_NO_VALGRIND;
    }
#else
    in_valgrind = GST_VG_NO_VALGRIND;
#endif
    g_assert (in_valgrind == GST_VG_NO_VALGRIND ||
        in_valgrind == GST_VG_INSIDE);
  }
  return (in_valgrind == GST_VG_INSIDE) ? TRUE : FALSE;
}

/**
 * _gst_debug_init:
 *
 * Initializes the debugging system.
 * Normally you don't want to call this, because gst_init() does it for you.
 */
void
_gst_debug_init (void)
{
  GTimeVal current;

  gst_atomic_int_set (&__default_level, GST_LEVEL_DEFAULT);
  gst_atomic_int_set (&__use_color, 1);

  /* get time we started for debugging messages */
  g_get_current_time (&current);
  start_time = GST_TIMEVAL_TO_TIME (current);

#ifdef HAVE_PRINTF_EXTENSION
  register_printf_function (GST_PTR_FORMAT[0], _gst_info_printf_extension_ptr,
      _gst_info_printf_extension_arginfo);
  register_printf_function (GST_SEGMENT_FORMAT[0],
      _gst_info_printf_extension_segment, _gst_info_printf_extension_arginfo);
#endif

  /* do NOT use a single debug function before this line has been run */
  GST_CAT_DEFAULT = _gst_debug_category_new ("default",
      GST_DEBUG_UNDERLINE, NULL);
  _GST_CAT_DEBUG = _gst_debug_category_new ("GST_DEBUG",
      GST_DEBUG_BOLD | GST_DEBUG_FG_YELLOW, "debugging subsystem");

  gst_debug_add_log_function (gst_debug_log_default, NULL);

  /* FIXME: add descriptions here */
  GST_CAT_GST_INIT = _gst_debug_category_new ("GST_INIT",
      GST_DEBUG_BOLD | GST_DEBUG_FG_RED, NULL);
  GST_CAT_AUTOPLUG = _gst_debug_category_new ("GST_AUTOPLUG",
      GST_DEBUG_BOLD | GST_DEBUG_FG_BLUE, NULL);
  GST_CAT_AUTOPLUG_ATTEMPT = _gst_debug_category_new ("GST_AUTOPLUG_ATTEMPT",
      GST_DEBUG_BOLD | GST_DEBUG_FG_CYAN | GST_DEBUG_BG_BLUE, NULL);
  GST_CAT_PARENTAGE = _gst_debug_category_new ("GST_PARENTAGE",
      GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, NULL);
  GST_CAT_STATES = _gst_debug_category_new ("GST_STATES",
      GST_DEBUG_BOLD | GST_DEBUG_FG_RED, NULL);
  GST_CAT_SCHEDULING = _gst_debug_category_new ("GST_SCHEDULING",
      GST_DEBUG_BOLD | GST_DEBUG_FG_MAGENTA, NULL);
  GST_CAT_BUFFER = _gst_debug_category_new ("GST_BUFFER",
      GST_DEBUG_BOLD | GST_DEBUG_BG_GREEN, NULL);
  GST_CAT_BUS = _gst_debug_category_new ("GST_BUS", GST_DEBUG_BG_YELLOW, NULL);
  GST_CAT_CAPS = _gst_debug_category_new ("GST_CAPS",
      GST_DEBUG_BOLD | GST_DEBUG_FG_BLUE, NULL);
  GST_CAT_CLOCK = _gst_debug_category_new ("GST_CLOCK",
      GST_DEBUG_BOLD | GST_DEBUG_FG_YELLOW, NULL);
  GST_CAT_ELEMENT_PADS = _gst_debug_category_new ("GST_ELEMENT_PADS",
      GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, NULL);
  GST_CAT_PADS = _gst_debug_category_new ("GST_PADS",
      GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, NULL);
  GST_CAT_PIPELINE = _gst_debug_category_new ("GST_PIPELINE",
      GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, NULL);
  GST_CAT_PLUGIN_LOADING = _gst_debug_category_new ("GST_PLUGIN_LOADING",
      GST_DEBUG_BOLD | GST_DEBUG_FG_CYAN, NULL);
  GST_CAT_PLUGIN_INFO = _gst_debug_category_new ("GST_PLUGIN_INFO",
      GST_DEBUG_BOLD | GST_DEBUG_FG_CYAN, NULL);
  GST_CAT_PROPERTIES = _gst_debug_category_new ("GST_PROPERTIES",
      GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_BLUE, NULL);
  GST_CAT_TYPES = _gst_debug_category_new ("GST_TYPES",
      GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, NULL);
  GST_CAT_XML = _gst_debug_category_new ("GST_XML",
      GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, NULL);
  GST_CAT_NEGOTIATION = _gst_debug_category_new ("GST_NEGOTIATION",
      GST_DEBUG_BOLD | GST_DEBUG_FG_BLUE, NULL);
  GST_CAT_REFCOUNTING = _gst_debug_category_new ("GST_REFCOUNTING",
      GST_DEBUG_BOLD | GST_DEBUG_FG_RED | GST_DEBUG_BG_BLUE, NULL);
  GST_CAT_ERROR_SYSTEM = _gst_debug_category_new ("GST_ERROR_SYSTEM",
      GST_DEBUG_BOLD | GST_DEBUG_FG_RED | GST_DEBUG_BG_WHITE, NULL);

  GST_CAT_EVENT = _gst_debug_category_new ("GST_EVENT",
      GST_DEBUG_BOLD | GST_DEBUG_FG_BLUE, NULL);
  GST_CAT_MESSAGE = _gst_debug_category_new ("GST_MESSAGE",
      GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, NULL);
  GST_CAT_PARAMS = _gst_debug_category_new ("GST_PARAMS",
      GST_DEBUG_BOLD | GST_DEBUG_FG_BLACK | GST_DEBUG_BG_YELLOW, NULL);
  GST_CAT_CALL_TRACE = _gst_debug_category_new ("GST_CALL_TRACE",
      GST_DEBUG_BOLD, NULL);
  GST_CAT_SIGNAL = _gst_debug_category_new ("GST_SIGNAL",
      GST_DEBUG_BOLD | GST_DEBUG_FG_WHITE | GST_DEBUG_BG_RED, NULL);
  GST_CAT_PROBE = _gst_debug_category_new ("GST_PROBE",
      GST_DEBUG_BOLD | GST_DEBUG_FG_GREEN, "pad probes");
  GST_CAT_REGISTRY = _gst_debug_category_new ("GST_REGISTRY", 0, "registry");
  GST_CAT_QOS = _gst_debug_category_new ("GST_QOS", 0, "QoS");


  /* print out the valgrind message if we're in valgrind */
  __gst_in_valgrind ();
}

/* we can't do this further above, because we initialize the GST_CAT_DEFAULT struct */
#define GST_CAT_DEFAULT _GST_CAT_DEBUG

/**
 * gst_debug_log:
 * @category: category to log
 * @level: level of the message is in
 * @file: the file that emitted the message, usually the __FILE__ identifier
 * @function: the function that emitted the message
 * @line: the line from that the message was emitted, usually __LINE__
 * @object: the object this message relates to or NULL if none
 * @format: a printf style format string
 * @...: optional arguments for the format
 *
 * Logs the given message using the currently registered debugging handlers.
 */
void
gst_debug_log (GstDebugCategory * category, GstDebugLevel level,
    const gchar * file, const gchar * function, gint line,
    GObject * object, const gchar * format, ...)
{
  va_list var_args;

  va_start (var_args, format);
  gst_debug_log_valist (category, level, file, function, line, object, format,
      var_args);
  va_end (var_args);
}

/**
 * gst_debug_log_valist:
 * @category: category to log
 * @level: level of the message is in
 * @file: the file that emitted the message, usually the __FILE__ identifier
 * @function: the function that emitted the message
 * @line: the line from that the message was emitted, usually __LINE__
 * @object: the object this message relates to or NULL if none
 * @format: a printf style format string
 * @args: optional arguments for the format
 *
 * Logs the given message using the currently registered debugging handlers.
 */
void
gst_debug_log_valist (GstDebugCategory * category, GstDebugLevel level,
    const gchar * file, const gchar * function, gint line,
    GObject * object, const gchar * format, va_list args)
{
  GstDebugMessage message;
  LogFuncEntry *entry;
  GSList *handler;

  g_return_if_fail (category != NULL);
  g_return_if_fail (file != NULL);
  g_return_if_fail (function != NULL);
  g_return_if_fail (format != NULL);

  message.message = NULL;
  message.format = format;
  G_VA_COPY (message.arguments, args);

  handler = __log_functions;
  while (handler) {
    entry = handler->data;
    handler = g_slist_next (handler);
    entry->func (category, level, file, function, line, object, &message,
        entry->user_data);
  }
  g_free (message.message);
  va_end (message.arguments);
}

/**
 * gst_debug_message_get:
 * @message: a debug message
 *
 * Gets the string representation of a #GstDebugMessage. This function is used
 * in debug handlers to extract the message.
 *
 * Returns: the string representation of a #GstDebugMessage.
 */
const gchar *
gst_debug_message_get (GstDebugMessage * message)
{
  if (message->message == NULL) {
    message->message = g_strdup_vprintf (message->format, message->arguments);
  }
  return message->message;
}


static gchar *
gst_debug_print_object (gpointer ptr)
{
  GObject *object = (GObject *) ptr;

#ifdef unused
  /* This is a cute trick to detect unmapped memory, but is unportable,
   * slow, screws around with madvise, and not actually that useful. */
  {
    int ret;

    ret = madvise ((void *) ((unsigned long) ptr & (~0xfff)), 4096, 0);
    if (ret == -1 && errno == ENOMEM) {
      buffer = g_strdup_printf ("%p (unmapped memory)", ptr);
    }
  }
#endif

  /* nicely printed object */
  if (object == NULL) {
    return g_strdup ("(NULL)");
  }
  if (*(GType *) ptr == GST_TYPE_CAPS) {
    return gst_caps_to_string ((GstCaps *) ptr);
  }
  if (*(GType *) ptr == GST_TYPE_STRUCTURE) {
    return gst_structure_to_string ((GstStructure *) ptr);
  }
#ifdef USE_POISONING
  if (*(guint32 *) ptr == 0xffffffff) {
    return g_strdup_printf ("<poisoned@%p>", ptr);
  }
#endif
  if (GST_IS_PAD (object) && GST_OBJECT_NAME (object)) {
    return g_strdup_printf ("<%s:%s>", GST_DEBUG_PAD_NAME (object));
  }
  if (GST_IS_OBJECT (object) && GST_OBJECT_NAME (object)) {
    return g_strdup_printf ("<%s>", GST_OBJECT_NAME (object));
  }
  if (G_IS_OBJECT (object)) {
    return g_strdup_printf ("<%s@%p>", G_OBJECT_TYPE_NAME (object), object);
  }

  return g_strdup_printf ("%p", ptr);
}

static gchar *
gst_debug_print_segment (gpointer ptr)
{
  GstSegment *segment = (GstSegment *) ptr;

  /* nicely printed segment */
  if (segment == NULL) {
    return g_strdup ("(NULL)");
  }

  switch (segment->format) {
    case GST_FORMAT_UNDEFINED:{
      return g_strdup_printf ("UNDEFINED segment");
    }
    case GST_FORMAT_TIME:{
      return g_strdup_printf ("time segment start=%" GST_TIME_FORMAT
          ", stop=%" GST_TIME_FORMAT ", last_stop=%" GST_TIME_FORMAT
          ", duration=%" GST_TIME_FORMAT ", rate=%f, applied_rate=%f"
          ", flags=0x%02x, time=%" GST_TIME_FORMAT ", accum=%" GST_TIME_FORMAT,
          GST_TIME_ARGS (segment->start), GST_TIME_ARGS (segment->stop),
          GST_TIME_ARGS (segment->last_stop), GST_TIME_ARGS (segment->duration),
          segment->rate, segment->applied_rate, (guint) segment->flags,
          GST_TIME_ARGS (segment->time), GST_TIME_ARGS (segment->accum));
    }
    default:{
      const gchar *format_name;

      format_name = gst_format_get_name (segment->format);
      if (G_UNLIKELY (format_name == NULL))
        format_name = "(UNKNOWN FORMAT)";
      return g_strdup_printf ("%s segment start=%" G_GINT64_FORMAT
          ", stop=%" G_GINT64_FORMAT ", last_stop=%" G_GINT64_FORMAT
          ", duration=%" G_GINT64_FORMAT ", rate=%f, applied_rate=%f"
          ", flags=0x%02x, time=%" GST_TIME_FORMAT ", accum=%" GST_TIME_FORMAT,
          format_name, segment->start, segment->stop, segment->last_stop,
          segment->duration, segment->rate, segment->applied_rate,
          (guint) segment->flags, GST_TIME_ARGS (segment->time),
          GST_TIME_ARGS (segment->accum));
    }
  }
}

/**
 * gst_debug_construct_term_color:
 * @colorinfo: the color info
 *
 * Constructs a string that can be used for getting the desired color in color
 * terminals.
 * You need to free the string after use.
 *
 * Returns: a string containing the color definition
 */
gchar *
gst_debug_construct_term_color (guint colorinfo)
{
  GString *color;
  gchar *ret;

  color = g_string_new ("\033[00");

  if (colorinfo & GST_DEBUG_BOLD) {
    g_string_append (color, ";01");
  }
  if (colorinfo & GST_DEBUG_UNDERLINE) {
    g_string_append (color, ";04");
  }
  if (colorinfo & GST_DEBUG_FG_MASK) {
    g_string_append_printf (color, ";3%1d", colorinfo & GST_DEBUG_FG_MASK);
  }
  if (colorinfo & GST_DEBUG_BG_MASK) {
    g_string_append_printf (color, ";4%1d",
        (colorinfo & GST_DEBUG_BG_MASK) >> 4);
  }
  g_string_append (color, "m");

  ret = color->str;
  g_string_free (color, FALSE);
  return ret;
}

/**
 * gst_debug_log_default:
 * @category: category to log
 * @level: level of the message
 * @file: the file that emitted the message, usually the __FILE__ identifier
 * @function: the function that emitted the message
 * @line: the line from that the message was emitted, usually __LINE__
 * @message: the actual message
 * @object: the object this message relates to or NULL if none
 * @unused: an unused variable, reserved for some user_data.
 *
 * The default logging handler used by GStreamer. Logging functions get called
 * whenever a macro like GST_DEBUG or similar is used. This function outputs the
 * message and additional info using the glib error handler.
 * You can add other handlers by using gst_debug_add_log_function().
 * And you can remove this handler by calling
 * gst_debug_remove_log_function(gst_debug_log_default);
 */
void
gst_debug_log_default (GstDebugCategory * category, GstDebugLevel level,
    const gchar * file, const gchar * function, gint line,
    GObject * object, GstDebugMessage * message, gpointer unused)
{
  gchar *color = NULL;
  gchar *clear;
  gchar *obj = NULL;
  gchar pidcolor[10];
  gint pid;
  GTimeVal now;
  GstClockTime elapsed;
  gboolean free_color = TRUE;
  gboolean free_obj = TRUE;

  if (level > gst_debug_category_get_threshold (category))
    return;

  pid = getpid ();

  /* color info */
  if (gst_debug_is_colored ()) {
    color = gst_debug_construct_term_color (gst_debug_category_get_color
        (category));
    clear = "\033[00m";
    g_sprintf (pidcolor, "\033[3%1dm", pid % 6 + 31);
  } else {
    color = "\0";
    free_color = FALSE;
    clear = "";
    pidcolor[0] = '\0';
  }

  if (object) {
    obj = gst_debug_print_object (object);
  } else {
    obj = "\0";
    free_obj = FALSE;
  }

  g_get_current_time (&now);
  elapsed = GST_TIMEVAL_TO_TIME (now) - start_time;
  g_printerr ("%s (%p - %" GST_TIME_FORMAT
      ") %s%20s%s(%s%5d%s) %s%s(%d):%s:%s%s %s\n",
      gst_debug_level_get_name (level), g_thread_self (),
      GST_TIME_ARGS (elapsed), color,
      gst_debug_category_get_name (category), clear, pidcolor, pid, clear,
      color, file, line, function, obj, clear, gst_debug_message_get (message));

  if (free_color)
    g_free (color);
  if (free_obj)
    g_free (obj);
}

/**
 * gst_debug_level_get_name:
 * @level: the level to get the name for
 *
 * Get the string trepresentation of a debugging level
 *
 * Returns: the name
 */
const gchar *
gst_debug_level_get_name (GstDebugLevel level)
{
  switch (level) {
    case GST_LEVEL_NONE:
      return "";
    case GST_LEVEL_ERROR:
      return "ERROR";
    case GST_LEVEL_WARNING:
      return "WARN ";
    case GST_LEVEL_INFO:
      return "INFO ";
    case GST_LEVEL_DEBUG:
      return "DEBUG";
    case GST_LEVEL_LOG:
      return "LOG  ";
    default:
      g_warning ("invalid level specified for gst_debug_level_get_name");
      return "";
  }
}

/**
 * gst_debug_add_log_function:
 * @func: the function to use
 * @data: user data
 *
 * Adds the logging function to the list of logging functions.
 * Be sure to use G_GNUC_NO_INSTRUMENT on that function, it is needed.
 */
void
gst_debug_add_log_function (GstLogFunction func, gpointer data)
{
  LogFuncEntry *entry;
  GSList *list;

  g_return_if_fail (func != NULL);

  entry = g_new (LogFuncEntry, 1);
  entry->func = func;
  entry->user_data = data;
  /* FIXME: we leak the old list here - other threads might access it right now
   * in gst_debug_logv. Another solution is to lock the mutex in gst_debug_logv,
   * but that is waaay costly.
   * It'd probably be clever to use some kind of RCU here, but I don't know
   * anything about that.
   */
  g_static_mutex_lock (&__log_func_mutex);
  list = g_slist_copy (__log_functions);
  __log_functions = g_slist_prepend (list, entry);
  g_static_mutex_unlock (&__log_func_mutex);

  GST_DEBUG ("prepended log function %p (user data %p) to log functions",
      func, data);
}

static gint
gst_debug_compare_log_function_by_func (gconstpointer entry, gconstpointer func)
{
  gpointer entryfunc = ((LogFuncEntry *) entry)->func;

  return (entryfunc < func) ? -1 : (entryfunc > func) ? 1 : 0;
}

static gint
gst_debug_compare_log_function_by_data (gconstpointer entry, gconstpointer data)
{
  gpointer entrydata = ((LogFuncEntry *) entry)->user_data;

  return (entrydata < data) ? -1 : (entrydata > data) ? 1 : 0;
}

static guint
gst_debug_remove_with_compare_func (GCompareFunc func, gpointer data)
{
  GSList *found;
  GSList *new;
  guint removals = 0;

  g_static_mutex_lock (&__log_func_mutex);
  new = __log_functions;
  while ((found = g_slist_find_custom (new, data, func))) {
    if (new == __log_functions) {
      new = g_slist_copy (new);
      continue;
    }
    g_free (found->data);
    new = g_slist_delete_link (new, found);
    removals++;
  }
  /* FIXME: We leak the old list here. See _add_log_function for why. */
  __log_functions = new;
  g_static_mutex_unlock (&__log_func_mutex);

  return removals;
}

/**
 * gst_debug_remove_log_function:
 * @func: the log function to remove
 *
 * Removes all registrered instances of the given logging functions.
 *
 * Returns: How many instances of the function were removed
 */
guint
gst_debug_remove_log_function (GstLogFunction func)
{
  guint removals;

  g_return_val_if_fail (func != NULL, 0);

  removals =
      gst_debug_remove_with_compare_func
      (gst_debug_compare_log_function_by_func, func);
  GST_DEBUG ("removed log function %p %d times from log function list", func,
      removals);

  return removals;
}

/**
 * gst_debug_remove_log_function_by_data:
 * @data: user data of the log function to remove
 *
 * Removes all registrered instances of log functions with the given user data.
 *
 * Returns: How many instances of the function were removed
 */
guint
gst_debug_remove_log_function_by_data (gpointer data)
{
  guint removals;

  removals =
      gst_debug_remove_with_compare_func
      (gst_debug_compare_log_function_by_data, data);
  GST_DEBUG
      ("removed %d log functions with user data %p from log function list",
      removals, data);

  return removals;
}

/**
 * gst_debug_set_colored:
 * @colored: Whether to use colored output or not
 *
 * Sets or unsets the use of coloured debugging output.
 */
void
gst_debug_set_colored (gboolean colored)
{
  gst_atomic_int_set (&__use_color, colored ? 1 : 0);
}

/**
 * gst_debug_is_colored:
 *
 * Checks if the debugging output should be colored.
 *
 * Returns: TRUE, if the debug output should be colored.
 */
gboolean
gst_debug_is_colored (void)
{
  return g_atomic_int_get (&__use_color) == 0 ? FALSE : TRUE;
}

/**
 * gst_debug_set_active:
 * @active: Whether to use debugging output or not
 *
 * If activated, debugging messages are sent to the debugging
 * handlers.
 * It makes sense to deactivate it for speed issues.
 * <note><para>This function is not threadsafe. It makes sense to only call it
 * during initialization.</para></note>
 */
void
gst_debug_set_active (gboolean active)
{
  __gst_debug_enabled = active;
  if (active)
    __gst_debug_min = GST_LEVEL_COUNT;
  else
    __gst_debug_min = GST_LEVEL_NONE;
}

/**
 * gst_debug_is_active:
 *
 * Checks if debugging output is activated.
 *
 * Returns: TRUE, if debugging is activated
 */
gboolean
gst_debug_is_active (void)
{
  return __gst_debug_enabled;
}

/**
 * gst_debug_set_default_threshold:
 * @level: level to set
 *
 * Sets the default threshold to the given level and updates all categories to
 * use this threshold.
 */
void
gst_debug_set_default_threshold (GstDebugLevel level)
{
  gst_atomic_int_set (&__default_level, level);
  gst_debug_reset_all_thresholds ();
}

/**
 * gst_debug_get_default_threshold:
 *
 * Returns the default threshold that is used for new categories.
 *
 * Returns: the default threshold level
 */
GstDebugLevel
gst_debug_get_default_threshold (void)
{
  return (GstDebugLevel) g_atomic_int_get (&__default_level);
}
static void
gst_debug_reset_threshold (gpointer category, gpointer unused)
{
  GstDebugCategory *cat = (GstDebugCategory *) category;
  GSList *walk;

  g_static_mutex_lock (&__level_name_mutex);
  walk = __level_name;
  while (walk) {
    LevelNameEntry *entry = walk->data;

    walk = g_slist_next (walk);
    if (g_pattern_match_string (entry->pat, cat->name)) {
      GST_LOG ("category %s matches pattern %p - gets set to level %d",
          cat->name, entry->pat, entry->level);
      gst_debug_category_set_threshold (cat, entry->level);
      goto exit;
    }
  }
  gst_debug_category_set_threshold (cat, gst_debug_get_default_threshold ());

exit:
  g_static_mutex_unlock (&__level_name_mutex);
}
static void
gst_debug_reset_all_thresholds (void)
{
  g_static_mutex_lock (&__cat_mutex);
  g_slist_foreach (__categories, gst_debug_reset_threshold, NULL);
  g_static_mutex_unlock (&__cat_mutex);
}
static void
for_each_threshold_by_entry (gpointer data, gpointer user_data)
{
  GstDebugCategory *cat = (GstDebugCategory *) data;
  LevelNameEntry *entry = (LevelNameEntry *) user_data;

  if (g_pattern_match_string (entry->pat, cat->name)) {
    GST_LOG ("category %s matches pattern %p - gets set to level %d",
        cat->name, entry->pat, entry->level);
    gst_debug_category_set_threshold (cat, entry->level);
  }
}

/**
 * gst_debug_set_threshold_for_name:
 * @name: name of the categories to set
 * @level: level to set them to
 *
 * Sets all categories which match the given glob style pattern to the given
 * level.
 */
void
gst_debug_set_threshold_for_name (const gchar * name, GstDebugLevel level)
{
  GPatternSpec *pat;
  LevelNameEntry *entry;

  g_return_if_fail (name != NULL);

  pat = g_pattern_spec_new (name);
  entry = g_new (LevelNameEntry, 1);
  entry->pat = pat;
  entry->level = level;
  g_static_mutex_lock (&__level_name_mutex);
  __level_name = g_slist_prepend (__level_name, entry);
  g_static_mutex_unlock (&__level_name_mutex);
  g_static_mutex_lock (&__cat_mutex);
  g_slist_foreach (__categories, for_each_threshold_by_entry, entry);
  g_static_mutex_unlock (&__cat_mutex);
}

/**
 * gst_debug_unset_threshold_for_name:
 * @name: name of the categories to set
 *
 * Resets all categories with the given name back to the default level.
 */
void
gst_debug_unset_threshold_for_name (const gchar * name)
{
  GSList *walk;
  GPatternSpec *pat;

  g_return_if_fail (name != NULL);

  pat = g_pattern_spec_new (name);
  g_static_mutex_lock (&__level_name_mutex);
  walk = __level_name;
  /* improve this if you want, it's mighty slow */
  while (walk) {
    LevelNameEntry *entry = walk->data;

    if (g_pattern_spec_equal (entry->pat, pat)) {
      __level_name = g_slist_remove_link (__level_name, walk);
      g_pattern_spec_free (entry->pat);
      g_free (entry);
      g_slist_free_1 (walk);
      walk = __level_name;
    }
  }
  g_static_mutex_unlock (&__level_name_mutex);
  g_pattern_spec_free (pat);
  gst_debug_reset_all_thresholds ();
}

GstDebugCategory *
_gst_debug_category_new (gchar * name, guint color, gchar * description)
{
  GstDebugCategory *cat;

  g_return_val_if_fail (name != NULL, NULL);

  cat = g_new (GstDebugCategory, 1);
  cat->name = g_strdup (name);
  cat->color = color;
  if (description != NULL) {
    cat->description = g_strdup (description);
  } else {
    cat->description = g_strdup ("no description");
  }
  gst_atomic_int_set (&cat->threshold, 0);
  gst_debug_reset_threshold (cat, NULL);

  /* add to category list */
  g_static_mutex_lock (&__cat_mutex);
  __categories = g_slist_prepend (__categories, cat);
  g_static_mutex_unlock (&__cat_mutex);

  return cat;
}

/**
 * gst_debug_category_free:
 * @category: #GstDebugCategory to free.
 *
 * Removes and frees the category and all associated resources.
 */
void
gst_debug_category_free (GstDebugCategory * category)
{
  if (category == NULL)
    return;

  /* remove from category list */
  g_static_mutex_lock (&__cat_mutex);
  __categories = g_slist_remove (__categories, category);
  g_static_mutex_unlock (&__cat_mutex);

  g_free ((gpointer) category->name);
  g_free ((gpointer) category->description);
  g_free (category);
}

/**
 * gst_debug_category_set_threshold:
 * @category: a #GstDebugCategory to set threshold of.
 * @level: the #GstDebugLevel threshold to set.
 *
 * Sets the threshold of the category to the given level. Debug information will
 * only be output if the threshold is lower or equal to the level of the
 * debugging message.
 * <note><para>
 * Do not use this function in production code, because other functions may
 * change the threshold of categories as side effect. It is however a nice
 * function to use when debugging (even from gdb).
 * </para></note>
 */
void
gst_debug_category_set_threshold (GstDebugCategory * category,
    GstDebugLevel level)
{
  g_return_if_fail (category != NULL);

  if (level > __gst_debug_min) {
    __gst_debug_enabled = TRUE;
    __gst_debug_min = level;
  }

  gst_atomic_int_set (&category->threshold, level);
}

/**
 * gst_debug_category_reset_threshold:
 * @category: a #GstDebugCategory to reset threshold of.
 *
 * Resets the threshold of the category to the default level. Debug information
 * will only be output if the threshold is lower or equal to the level of the
 * debugging message.
 * Use this function to set the threshold back to where it was after using
 * gst_debug_category_set_threshold().
 */
void
gst_debug_category_reset_threshold (GstDebugCategory * category)
{
  gst_debug_reset_threshold (category, NULL);
}

/**
 * gst_debug_category_get_threshold:
 * @category: a #GstDebugCategory to get threshold of.
 *
 * Returns the threshold of a #GstCategory.
 *
 * Returns: the #GstDebugLevel that is used as threshold.
 */
GstDebugLevel
gst_debug_category_get_threshold (GstDebugCategory * category)
{
  return g_atomic_int_get (&category->threshold);
}

/**
 * gst_debug_category_get_name:
 * @category: a #GstDebugCategory to get name of.
 *
 * Returns the name of a debug category.
 *
 * Returns: the name of the category.
 */
const gchar *
gst_debug_category_get_name (GstDebugCategory * category)
{
  return category->name;
}

/**
 * gst_debug_category_get_color:
 * @category: a #GstDebugCategory to get the color of.
 *
 * Returns the color of a debug category used when printing output in this
 * category.
 *
 * Returns: the color of the category.
 */
guint
gst_debug_category_get_color (GstDebugCategory * category)
{
  return category->color;
}

/**
 * gst_debug_category_get_description:
 * @category: a #GstDebugCategory to get the description of.
 *
 * Returns the description of a debug category.
 *
 * Returns: the description of the category.
 */
const gchar *
gst_debug_category_get_description (GstDebugCategory * category)
{
  return category->description;
}

/**
 * gst_debug_get_all_categories:
 *
 * Returns a snapshot of a all categories that are currently in use . This list
 * may change anytime.
 * The caller has to free the list after use.
 *
 * Returns: the list of categories
 */
GSList *
gst_debug_get_all_categories (void)
{
  GSList *ret;

  g_static_mutex_lock (&__cat_mutex);
  ret = g_slist_copy (__categories);
  g_static_mutex_unlock (&__cat_mutex);

  return ret;
}

/*** FUNCTION POINTERS ********************************************************/

static GHashTable *__gst_function_pointers;     /* NULL */
static GStaticMutex __dbg_functions_mutex = G_STATIC_MUTEX_INIT;

const gchar *
_gst_debug_nameof_funcptr (GstDebugFuncPtr ptr)
    G_GNUC_NO_INSTRUMENT;

/* This function MUST NOT return NULL */
     const gchar *_gst_debug_nameof_funcptr (GstDebugFuncPtr func)
{
  gpointer ptr = (gpointer) func;
  gchar *ptrname;

#ifdef HAVE_DLADDR
  Dl_info dlinfo;
#endif

  if (G_LIKELY (__gst_function_pointers)) {
    g_static_mutex_lock (&__dbg_functions_mutex);
    ptrname = g_hash_table_lookup (__gst_function_pointers, ptr);
    g_static_mutex_unlock (&__dbg_functions_mutex);
    if (G_LIKELY (ptrname))
      return ptrname;
  }
  /* we need to create an entry in the hash table for this one so we don't leak
   * the name */
#ifdef HAVE_DLADDR
  if (dladdr (ptr, &dlinfo) && dlinfo.dli_sname) {
    gchar *name = g_strdup (dlinfo.dli_sname);

    _gst_debug_register_funcptr (ptr, name);
    return name;
  } else
#endif
  {
    gchar *name = g_strdup_printf ("%p", ptr);

    _gst_debug_register_funcptr (ptr, name);
    return name;
  }
}

void
_gst_debug_register_funcptr (GstDebugFuncPtr func, gchar * ptrname)
{
  gpointer ptr = (gpointer) func;

  g_static_mutex_lock (&__dbg_functions_mutex);

  if (!__gst_function_pointers)
    __gst_function_pointers = g_hash_table_new (g_direct_hash, g_direct_equal);
  if (!g_hash_table_lookup (__gst_function_pointers, ptr))
    g_hash_table_insert (__gst_function_pointers, ptr, ptrname);

  g_static_mutex_unlock (&__dbg_functions_mutex);
}

#ifdef HAVE_PRINTF_EXTENSION
static int
_gst_info_printf_extension_ptr (FILE * stream, const struct printf_info *info,
    const void *const *args)
{
  char *buffer;
  int len;
  void *ptr;

  buffer = NULL;
  ptr = *(void **) args[0];

  buffer = gst_debug_print_object (ptr);
  len = fprintf (stream, "%*s", (info->left ? -info->width : info->width),
      buffer);

  g_free (buffer);
  return len;
}

static int
_gst_info_printf_extension_segment (FILE * stream,
    const struct printf_info *info, const void *const *args)
{
  char *buffer;
  int len;
  void *ptr;

  buffer = NULL;
  ptr = *(void **) args[0];

  buffer = gst_debug_print_segment (ptr);
  len = fprintf (stream, "%*s", (info->left ? -info->width : info->width),
      buffer);

  g_free (buffer);
  return len;
}

static int
_gst_info_printf_extension_arginfo (const struct printf_info *info, size_t n,
    int *argtypes)
{
  if (n > 0)
    argtypes[0] = PA_POINTER;
  return 1;
}
#endif /* HAVE_PRINTF_EXTENSION */

#else /* !GST_DISABLE_GST_DEBUG */
guint
gst_debug_remove_log_function (GstLogFunction func)
{
  return 0;
}

guint
gst_debug_remove_log_function_by_data (gpointer data)
{
  return 0;
}

gboolean
__gst_in_valgrind (void)
{
  return FALSE;
}

#endif /* GST_DISABLE_GST_DEBUG */


#ifdef GST_ENABLE_FUNC_INSTRUMENTATION
/* FIXME make this thread specific */
static GSList *stack_trace = NULL;

void
__cyg_profile_func_enter (void *this_fn, void *call_site)
    G_GNUC_NO_INSTRUMENT;
     void __cyg_profile_func_enter (void *this_fn, void *call_site)
{
  gchar *name = _gst_debug_nameof_funcptr (this_fn);
  gchar *site = _gst_debug_nameof_funcptr (call_site);

  GST_CAT_DEBUG (GST_CAT_CALL_TRACE, "entering function %s from %s", name,
      site);
  stack_trace =
      g_slist_prepend (stack_trace, g_strdup_printf ("%8p in %s from %p (%s)",
          this_fn, name, call_site, site));

  g_free (name);
  g_free (site);
}

void
__cyg_profile_func_exit (void *this_fn, void *call_site)
    G_GNUC_NO_INSTRUMENT;
     void __cyg_profile_func_exit (void *this_fn, void *call_site)
{
  gchar *name = _gst_debug_nameof_funcptr (this_fn);

  GST_CAT_DEBUG (GST_CAT_CALL_TRACE, "leaving function %s", name);
  g_free (stack_trace->data);
  stack_trace = g_slist_delete_link (stack_trace, stack_trace);

  g_free (name);
}

/**
 * gst_debug_print_stack_trace:
 *
 * If GST_ENABLE_FUNC_INSTRUMENTATION is defined a stacktracke is available for
 * gstreamer code, which can be printed with this function.
 */
void
gst_debug_print_stack_trace (void)
{
  GSList *walk = stack_trace;
  gint count = 0;

  if (walk)
    walk = g_slist_next (walk);

  while (walk) {
    gchar *name = (gchar *) walk->data;

    g_print ("#%-2d %s\n", count++, name);

    walk = g_slist_next (walk);
  }
}
#else
void
gst_debug_print_stack_trace (void)
{
  /* nothing because it's compiled out */
}

#endif /* GST_ENABLE_FUNC_INTSTRUMENTATION */