source: trunk/third/glib2/gobject/gparam.c @ 20721

/* GObject - GLib Type, Object, Parameter and Signal Library
 * Copyright (C) 1997-1999, 2000-2001 Tim Janik and Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser 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.
 */

/*
 * MT safe
 */

#include        "gparam.h"
#include        "gparamspecs.h"

#include        "gvaluecollector.h"
#include        <string.h>



/* --- defines --- */
#define G_PARAM_USER_MASK                       (~0 << G_PARAM_USER_SHIFT)
#define PSPEC_APPLIES_TO_VALUE(pspec, value)    (G_TYPE_CHECK_VALUE_TYPE ((value), G_PARAM_SPEC_VALUE_TYPE (pspec)))
#define G_SLOCK(mutex)                          g_static_mutex_lock (mutex)
#define G_SUNLOCK(mutex)                        g_static_mutex_unlock (mutex)


/* --- prototypes --- */
static void     g_param_spec_class_base_init     (GParamSpecClass       *class);
static void     g_param_spec_class_base_finalize (GParamSpecClass       *class);
static void     g_param_spec_class_init          (GParamSpecClass       *class,
                                                  gpointer               class_data);
static void     g_param_spec_init                (GParamSpec            *pspec,
                                                  GParamSpecClass       *class);
static void     g_param_spec_finalize            (GParamSpec            *pspec);
static void     value_param_init                (GValue         *value);
static void     value_param_free_value          (GValue         *value);
static void     value_param_copy_value          (const GValue   *src_value,
                                                 GValue         *dest_value);
static void     value_param_transform_value     (const GValue   *src_value,
                                                 GValue         *dest_value);
static gpointer value_param_peek_pointer        (const GValue   *value);
static gchar*   value_param_collect_value       (GValue         *value,
                                                 guint           n_collect_values,
                                                 GTypeCValue    *collect_values,
                                                 guint           collect_flags);
static gchar*   value_param_lcopy_value         (const GValue   *value,
                                                 guint           n_collect_values,
                                                 GTypeCValue    *collect_values,
                                                 guint           collect_flags);


/* --- variables --- */
static GQuark quark_floating = 0;
G_LOCK_DEFINE_STATIC (pspec_ref_count);


/* --- functions --- */
void
g_param_type_init (void)        /* sync with gtype.c */
{
  static const GTypeFundamentalInfo finfo = {
    (G_TYPE_FLAG_CLASSED |
     G_TYPE_FLAG_INSTANTIATABLE |
     G_TYPE_FLAG_DERIVABLE |
     G_TYPE_FLAG_DEEP_DERIVABLE),
  };
  static const GTypeValueTable param_value_table = {
    value_param_init,           /* value_init */
    value_param_free_value,     /* value_free */
    value_param_copy_value,     /* value_copy */
    value_param_peek_pointer,   /* value_peek_pointer */
    "p",                        /* collect_format */
    value_param_collect_value,  /* collect_value */
    "p",                        /* lcopy_format */
    value_param_lcopy_value,    /* lcopy_value */
  };
  static const GTypeInfo param_spec_info = {
    sizeof (GParamSpecClass),

    (GBaseInitFunc) g_param_spec_class_base_init,
    (GBaseFinalizeFunc) g_param_spec_class_base_finalize,
    (GClassInitFunc) g_param_spec_class_init,
    (GClassFinalizeFunc) NULL,
    NULL,       /* class_data */

    sizeof (GParamSpec),
    0,          /* n_preallocs */
    (GInstanceInitFunc) g_param_spec_init,

    &param_value_table,
  };
  GType type;

  type = g_type_register_fundamental (G_TYPE_PARAM, "GParam", &param_spec_info, &finfo, G_TYPE_FLAG_ABSTRACT);
  g_assert (type == G_TYPE_PARAM);
  g_value_register_transform_func (G_TYPE_PARAM, G_TYPE_PARAM, value_param_transform_value);
}

static void
g_param_spec_class_base_init (GParamSpecClass *class)
{
}

static void
g_param_spec_class_base_finalize (GParamSpecClass *class)
{
}

static void
g_param_spec_class_init (GParamSpecClass *class,
                         gpointer         class_data)
{
  quark_floating = g_quark_from_static_string ("GParamSpec-floating");

  class->value_type = G_TYPE_NONE;
  class->finalize = g_param_spec_finalize;
  class->value_set_default = NULL;
  class->value_validate = NULL;
  class->values_cmp = NULL;
}

static void
g_param_spec_init (GParamSpec      *pspec,
                   GParamSpecClass *class)
{
  pspec->name = NULL;
  pspec->_nick = NULL;
  pspec->_blurb = NULL;
  pspec->flags = 0;
  pspec->value_type = class->value_type;
  pspec->owner_type = 0;
  pspec->qdata = NULL;
  pspec->ref_count = 1;
  pspec->param_id = 0;
  g_datalist_id_set_data (&pspec->qdata, quark_floating, GUINT_TO_POINTER (TRUE));
}

static void
g_param_spec_finalize (GParamSpec *pspec)
{
  g_datalist_clear (&pspec->qdata);
  
  g_free (pspec->name);
  g_free (pspec->_nick);
  g_free (pspec->_blurb);

  g_type_free_instance ((GTypeInstance*) pspec);
}

GParamSpec*
g_param_spec_ref (GParamSpec *pspec)
{
  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), NULL);

  G_LOCK (pspec_ref_count);
  if (pspec->ref_count > 0)
    {
      pspec->ref_count += 1;
      G_UNLOCK (pspec_ref_count);
    }
  else
    {
      G_UNLOCK (pspec_ref_count);
      g_return_val_if_fail (pspec->ref_count > 0, NULL);
    }
  
  return pspec;
}

void
g_param_spec_unref (GParamSpec *pspec)
{
  g_return_if_fail (G_IS_PARAM_SPEC (pspec));

  G_LOCK (pspec_ref_count);
  if (pspec->ref_count > 0)
    {
      gboolean need_finalize;

      /* sync with _sink */
      pspec->ref_count -= 1;
      need_finalize = pspec->ref_count == 0;
      G_UNLOCK (pspec_ref_count);
      if (need_finalize)
        G_PARAM_SPEC_GET_CLASS (pspec)->finalize (pspec);
    }
  else
    {
      G_UNLOCK (pspec_ref_count);
      g_return_if_fail (pspec->ref_count > 0);
    }
}

void
g_param_spec_sink (GParamSpec *pspec)
{
  g_return_if_fail (G_IS_PARAM_SPEC (pspec));

  G_LOCK (pspec_ref_count);
  if (pspec->ref_count > 0)
    {
      if (g_datalist_id_remove_no_notify (&pspec->qdata, quark_floating))
        {
          /* sync with _unref */
          if (pspec->ref_count > 1)
            pspec->ref_count -= 1;
          else
            {
              G_UNLOCK (pspec_ref_count);
              g_param_spec_unref (pspec);

              return;
            }
        }
      G_UNLOCK (pspec_ref_count);
    }
  else
    {
      G_UNLOCK (pspec_ref_count);
      g_return_if_fail (pspec->ref_count > 0);
    }
}

G_CONST_RETURN gchar*
g_param_spec_get_name (GParamSpec *pspec)
{
  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), NULL);

  return pspec->name;
}

G_CONST_RETURN gchar*
g_param_spec_get_nick (GParamSpec *pspec)
{
  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), NULL);

  if (pspec->_nick)
    return pspec->_nick;
  else
    {
      GParamSpec *redirect_target;

      redirect_target = g_param_spec_get_redirect_target (pspec);
      if (redirect_target && redirect_target->_nick)
        return redirect_target->_nick;
    }

  return pspec->name;
}

G_CONST_RETURN gchar*
g_param_spec_get_blurb (GParamSpec *pspec)
{
  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), NULL);

  if (pspec->_blurb)
    return pspec->_blurb;
  else
    {
      GParamSpec *redirect_target;

      redirect_target = g_param_spec_get_redirect_target (pspec);
      if (redirect_target && redirect_target->_blurb)
        return redirect_target->_blurb;
    }

  return NULL;
}

static void
canonicalize_key (gchar *key)
{
  gchar *p;
  
  for (p = key; *p != 0; p++)
    {
      gchar c = *p;
      
      if (c != '-' &&
          (c < '0' || c > '9') &&
          (c < 'A' || c > 'Z') &&
          (c < 'a' || c > 'z'))
        *p = '-';
    }
}

gpointer
g_param_spec_internal (GType        param_type,
                       const gchar *name,
                       const gchar *nick,
                       const gchar *blurb,
                       GParamFlags  flags)
{
  GParamSpec *pspec;
  
  g_return_val_if_fail (G_TYPE_IS_PARAM (param_type) && param_type != G_TYPE_PARAM, NULL);
  g_return_val_if_fail (name != NULL, NULL);
  g_return_val_if_fail ((name[0] >= 'A' && name[0] <= 'Z') || (name[0] >= 'a' && name[0] <= 'z'), NULL);
  
  pspec = (gpointer) g_type_create_instance (param_type);
  pspec->name = g_strdup (name);
  canonicalize_key (pspec->name);
  pspec->_nick = g_strdup (nick);
  pspec->_blurb = g_strdup (blurb);
  pspec->flags = (flags & G_PARAM_USER_MASK) | (flags & G_PARAM_MASK);
  
  return pspec;
}

gpointer
g_param_spec_get_qdata (GParamSpec *pspec,
                        GQuark      quark)
{
  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), NULL);
  
  return quark ? g_datalist_id_get_data (&pspec->qdata, quark) : NULL;
}

void
g_param_spec_set_qdata (GParamSpec *pspec,
                        GQuark      quark,
                        gpointer    data)
{
  g_return_if_fail (G_IS_PARAM_SPEC (pspec));
  g_return_if_fail (quark > 0);

  g_datalist_id_set_data (&pspec->qdata, quark, data);
}

void
g_param_spec_set_qdata_full (GParamSpec    *pspec,
                             GQuark         quark,
                             gpointer       data,
                             GDestroyNotify destroy)
{
  g_return_if_fail (G_IS_PARAM_SPEC (pspec));
  g_return_if_fail (quark > 0);

  g_datalist_id_set_data_full (&pspec->qdata, quark, data, data ? destroy : (GDestroyNotify) NULL);
}

gpointer
g_param_spec_steal_qdata (GParamSpec *pspec,
                          GQuark      quark)
{
  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), NULL);
  g_return_val_if_fail (quark > 0, NULL);
  
  return g_datalist_id_remove_no_notify (&pspec->qdata, quark);
}

GParamSpec*
g_param_spec_get_redirect_target (GParamSpec *pspec)
{
  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), NULL);

  if (G_IS_PARAM_SPEC_OVERRIDE (pspec))
    {
      GParamSpecOverride *ospec = G_PARAM_SPEC_OVERRIDE (pspec);

      return ospec->overridden;
    }
  else
    return NULL;
}

void
g_param_value_set_default (GParamSpec *pspec,
                           GValue     *value)
{
  g_return_if_fail (G_IS_PARAM_SPEC (pspec));
  g_return_if_fail (G_IS_VALUE (value));
  g_return_if_fail (PSPEC_APPLIES_TO_VALUE (pspec, value));

  g_value_reset (value);
  G_PARAM_SPEC_GET_CLASS (pspec)->value_set_default (pspec, value);
}

gboolean
g_param_value_defaults (GParamSpec *pspec,
                        GValue     *value)
{
  GValue dflt_value = { 0, };
  gboolean defaults;

  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), FALSE);
  g_return_val_if_fail (G_IS_VALUE (value), FALSE);
  g_return_val_if_fail (PSPEC_APPLIES_TO_VALUE (pspec, value), FALSE);

  g_value_init (&dflt_value, G_PARAM_SPEC_VALUE_TYPE (pspec));
  G_PARAM_SPEC_GET_CLASS (pspec)->value_set_default (pspec, &dflt_value);
  defaults = G_PARAM_SPEC_GET_CLASS (pspec)->values_cmp (pspec, value, &dflt_value) == 0;
  g_value_unset (&dflt_value);

  return defaults;
}

gboolean
g_param_value_validate (GParamSpec *pspec,
                        GValue     *value)
{
  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), FALSE);
  g_return_val_if_fail (G_IS_VALUE (value), FALSE);
  g_return_val_if_fail (PSPEC_APPLIES_TO_VALUE (pspec, value), FALSE);

  if (G_PARAM_SPEC_GET_CLASS (pspec)->value_validate)
    {
      GValue oval = *value;

      if (G_PARAM_SPEC_GET_CLASS (pspec)->value_validate (pspec, value) ||
          memcmp (&oval.data, &value->data, sizeof (oval.data)))
        return TRUE;
    }

  return FALSE;
}

gboolean
g_param_value_convert (GParamSpec   *pspec,
                       const GValue *src_value,
                       GValue       *dest_value,
                       gboolean      strict_validation)
{
  GValue tmp_value = { 0, };

  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), FALSE);
  g_return_val_if_fail (G_IS_VALUE (src_value), FALSE);
  g_return_val_if_fail (G_IS_VALUE (dest_value), FALSE);
  g_return_val_if_fail (PSPEC_APPLIES_TO_VALUE (pspec, dest_value), FALSE);

  /* better leave dest_value untouched when returning FALSE */

  g_value_init (&tmp_value, G_VALUE_TYPE (dest_value));
  if (g_value_transform (src_value, &tmp_value) &&
      (!g_param_value_validate (pspec, &tmp_value) || !strict_validation))
    {
      g_value_unset (dest_value);
      
      /* values are relocatable */
      memcpy (dest_value, &tmp_value, sizeof (tmp_value));
      
      return TRUE;
    }
  else
    {
      g_value_unset (&tmp_value);
      
      return FALSE;
    }
}

gint
g_param_values_cmp (GParamSpec   *pspec,
                    const GValue *value1,
                    const GValue *value2)
{
  gint cmp;

  /* param_values_cmp() effectively does: value1 - value2
   * so the return values are:
   * -1)  value1 < value2
   *  0)  value1 == value2
   *  1)  value1 > value2
   */
  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), 0);
  g_return_val_if_fail (G_IS_VALUE (value1), 0);
  g_return_val_if_fail (G_IS_VALUE (value2), 0);
  g_return_val_if_fail (PSPEC_APPLIES_TO_VALUE (pspec, value1), 0);
  g_return_val_if_fail (PSPEC_APPLIES_TO_VALUE (pspec, value2), 0);

  cmp = G_PARAM_SPEC_GET_CLASS (pspec)->values_cmp (pspec, value1, value2);

  return CLAMP (cmp, -1, 1);
}

static void
value_param_init (GValue *value)
{
  value->data[0].v_pointer = NULL;
}

static void
value_param_free_value (GValue *value)
{
  if (value->data[0].v_pointer)
    g_param_spec_unref (value->data[0].v_pointer);
}

static void
value_param_copy_value (const GValue *src_value,
                        GValue       *dest_value)
{
  if (src_value->data[0].v_pointer)
    dest_value->data[0].v_pointer = g_param_spec_ref (src_value->data[0].v_pointer);
  else
    dest_value->data[0].v_pointer = NULL;
}

static void
value_param_transform_value (const GValue *src_value,
                             GValue       *dest_value)
{
  if (src_value->data[0].v_pointer &&
      g_type_is_a (G_PARAM_SPEC_TYPE (dest_value->data[0].v_pointer), G_VALUE_TYPE (dest_value)))
    dest_value->data[0].v_pointer = g_param_spec_ref (src_value->data[0].v_pointer);
  else
    dest_value->data[0].v_pointer = NULL;
}

static gpointer
value_param_peek_pointer (const GValue *value)
{
  return value->data[0].v_pointer;
}

static gchar*
value_param_collect_value (GValue      *value,
                           guint        n_collect_values,
                           GTypeCValue *collect_values,
                           guint        collect_flags)
{
  if (collect_values[0].v_pointer)
    {
      GParamSpec *param = collect_values[0].v_pointer;

      if (param->g_type_instance.g_class == NULL)
        return g_strconcat ("invalid unclassed param spec pointer for value type `",
                            G_VALUE_TYPE_NAME (value),
                            "'",
                            NULL);
      else if (!g_value_type_compatible (G_PARAM_SPEC_TYPE (param), G_VALUE_TYPE (value)))
        return g_strconcat ("invalid param spec type `",
                            G_PARAM_SPEC_TYPE_NAME (param),
                            "' for value type `",
                            G_VALUE_TYPE_NAME (value),
                            "'",
                            NULL);
      value->data[0].v_pointer = g_param_spec_ref (param);
    }
  else
    value->data[0].v_pointer = NULL;

  return NULL;
}

static gchar*
value_param_lcopy_value (const GValue *value,
                         guint         n_collect_values,
                         GTypeCValue  *collect_values,
                         guint         collect_flags)
{
  GParamSpec **param_p = collect_values[0].v_pointer;

  if (!param_p)
    return g_strdup_printf ("value location for `%s' passed as NULL", G_VALUE_TYPE_NAME (value));

  if (!value->data[0].v_pointer)
    *param_p = NULL;
  else if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
    *param_p = value->data[0].v_pointer;
  else
    *param_p = g_param_spec_ref (value->data[0].v_pointer);

  return NULL;
}


/* --- param spec pool --- */
struct _GParamSpecPool
{
  GStaticMutex smutex;
  gboolean     type_prefixing;
  GHashTable  *hash_table;
};

static guint
param_spec_pool_hash (gconstpointer key_spec)
{
  const GParamSpec *key = key_spec;
  const gchar *p;
  guint h = key->owner_type;

  for (p = key->name; *p; p++)
    h = (h << 5) - h + *p;

  return h;
}

static gboolean
param_spec_pool_equals (gconstpointer key_spec_1,
                        gconstpointer key_spec_2)
{
  const GParamSpec *key1 = key_spec_1;
  const GParamSpec *key2 = key_spec_2;

  return (key1->owner_type == key2->owner_type &&
          strcmp (key1->name, key2->name) == 0);
}

GParamSpecPool*
g_param_spec_pool_new (gboolean type_prefixing)
{
  static GStaticMutex init_smutex = G_STATIC_MUTEX_INIT;
  GParamSpecPool *pool = g_new (GParamSpecPool, 1);

  memcpy (&pool->smutex, &init_smutex, sizeof (init_smutex));
  pool->type_prefixing = type_prefixing != FALSE;
  pool->hash_table = g_hash_table_new (param_spec_pool_hash, param_spec_pool_equals);

  return pool;
}

void
g_param_spec_pool_insert (GParamSpecPool *pool,
                          GParamSpec     *pspec,
                          GType           owner_type)
{
  gchar *p;
  
  if (pool && pspec && owner_type > 0 && pspec->owner_type == 0)
    {
      G_SLOCK (&pool->smutex);
      for (p = pspec->name; *p; p++)
        {
          if (!strchr (G_CSET_A_2_Z G_CSET_a_2_z G_CSET_DIGITS "-_", *p))
            {
              g_warning (G_STRLOC ": pspec name \"%s\" contains invalid characters", pspec->name);
              G_SUNLOCK (&pool->smutex);
              return;
            }
        }
      
      pspec->owner_type = owner_type;
      g_param_spec_ref (pspec);
      g_hash_table_insert (pool->hash_table, pspec, pspec);
      G_SUNLOCK (&pool->smutex);
    }
  else
    {
      g_return_if_fail (pool != NULL);
      g_return_if_fail (pspec);
      g_return_if_fail (owner_type > 0);
      g_return_if_fail (pspec->owner_type == 0);
    }
}

void
g_param_spec_pool_remove (GParamSpecPool *pool,
                          GParamSpec     *pspec)
{
  if (pool && pspec)
    {
      G_SLOCK (&pool->smutex);
      if (g_hash_table_remove (pool->hash_table, pspec))
        g_param_spec_unref (pspec);
      else
        g_warning (G_STRLOC ": attempt to remove unknown pspec `%s' from pool", pspec->name);
      G_SUNLOCK (&pool->smutex);
    }
  else
    {
      g_return_if_fail (pool != NULL);
      g_return_if_fail (pspec);
    }
}

static inline GParamSpec*
param_spec_ht_lookup (GHashTable  *hash_table,
                      const gchar *param_name,
                      GType        owner_type,
                      gboolean     walk_ancestors)
{
  GParamSpec key, *pspec;

  key.owner_type = owner_type;
  key.name = (gchar*) param_name;
  if (walk_ancestors)
    do
      {
        pspec = g_hash_table_lookup (hash_table, &key);
        if (pspec)
          return pspec;
        key.owner_type = g_type_parent (key.owner_type);
      }
    while (key.owner_type);
  else
    pspec = g_hash_table_lookup (hash_table, &key);

  if (!pspec)
    {
      /* try canonicalized form */
      key.name = g_strdup (param_name);
      key.owner_type = owner_type;
      
      canonicalize_key (key.name);
      if (walk_ancestors)
        do
          {
            pspec = g_hash_table_lookup (hash_table, &key);
            if (pspec)
              {
                g_free (key.name);
                return pspec;
              }
            key.owner_type = g_type_parent (key.owner_type);
          }
        while (key.owner_type);
      else
        pspec = g_hash_table_lookup (hash_table, &key);
      g_free (key.name);
    }

  return pspec;
}

GParamSpec*
g_param_spec_pool_lookup (GParamSpecPool *pool,
                          const gchar    *param_name,
                          GType           owner_type,
                          gboolean        walk_ancestors)
{
  GParamSpec *pspec;
  gchar *delim;

  if (!pool || !param_name)
    {
      g_return_val_if_fail (pool != NULL, NULL);
      g_return_val_if_fail (param_name != NULL, NULL);
    }

  G_SLOCK (&pool->smutex);

  delim = pool->type_prefixing ? strchr (param_name, ':') : NULL;

  /* try quick and away, i.e. without prefix */
  if (!delim)
    {
      pspec = param_spec_ht_lookup (pool->hash_table, param_name, owner_type, walk_ancestors);
      G_SUNLOCK (&pool->smutex);

      return pspec;
    }

  /* strip type prefix */
  if (pool->type_prefixing && delim[1] == ':')
    {
      guint l = delim - param_name;
      gchar stack_buffer[32], *buffer = l < 32 ? stack_buffer : g_new (gchar, l + 1);
      GType type;
      
      strncpy (buffer, param_name, delim - param_name);
      buffer[l] = 0;
      type = g_type_from_name (buffer);
      if (l >= 32)
        g_free (buffer);
      if (type)         /* type==0 isn't a valid type pefix */
        {
          /* sanity check, these cases don't make a whole lot of sense */
          if ((!walk_ancestors && type != owner_type) || !g_type_is_a (owner_type, type))
            {
              G_SUNLOCK (&pool->smutex);

              return NULL;
            }
          owner_type = type;
          param_name += l + 2;
          pspec = param_spec_ht_lookup (pool->hash_table, param_name, owner_type, walk_ancestors);
          G_SUNLOCK (&pool->smutex);

          return pspec;
        }
    }
  /* malformed param_name */

  G_SUNLOCK (&pool->smutex);

  return NULL;
}

static void
pool_list (gpointer key,
           gpointer value,
           gpointer user_data)
{
  GParamSpec *pspec = value;
  gpointer *data = user_data;
  GType owner_type = (GType) data[1];

  if (owner_type == pspec->owner_type)
    data[0] = g_list_prepend (data[0], pspec);
}

GList*
g_param_spec_pool_list_owned (GParamSpecPool *pool,
                              GType           owner_type)
{
  gpointer data[2];

  g_return_val_if_fail (pool != NULL, NULL);
  g_return_val_if_fail (owner_type > 0, NULL);
  
  G_SLOCK (&pool->smutex);
  data[0] = NULL;
  data[1] = (gpointer) owner_type;
  g_hash_table_foreach (pool->hash_table, pool_list, &data);
  G_SUNLOCK (&pool->smutex);

  return data[0];
}

static gint
pspec_compare_id (gconstpointer a,
                  gconstpointer b)
{
  const GParamSpec *pspec1 = a, *pspec2 = b;

  return pspec1->param_id < pspec2->param_id ? -1 : pspec1->param_id > pspec2->param_id;
}

static inline GSList*
pspec_list_remove_overridden_and_redirected (GSList     *plist,
                                             GHashTable *ht,
                                             GType       owner_type,
                                             guint      *n_p)
{
  GSList *rlist = NULL;

  while (plist)
    {
      GSList *tmp = plist->next;
      GParamSpec *pspec = plist->data;
      GParamSpec *found;
      gboolean remove = FALSE;

      /* Remove paramspecs that are redirected, and also paramspecs
       * that have are overridden by non-redirected properties.
       * The idea is to get the single paramspec for each name that
       * best corresponds to what the application sees.
       */
      if (g_param_spec_get_redirect_target (pspec))
        remove = TRUE;
      else
        {
          found = param_spec_ht_lookup (ht, pspec->name, owner_type, TRUE);
          if (found != pspec)
            {
              GParamSpec *redirect = g_param_spec_get_redirect_target (found);
              if (redirect != pspec)
                remove = TRUE;
            }
        }

      if (remove)
        {
          g_slist_free_1 (plist);
        }
      else
        {
          plist->next = rlist;
          rlist = plist;
          *n_p += 1;
        }
      plist = tmp;
    }
  return rlist;
}

static void
pool_depth_list (gpointer key,
                 gpointer value,
                 gpointer user_data)
{
  GParamSpec *pspec = value;
  gpointer *data = user_data;
  GSList **slists = data[0];
  GType owner_type = (GType) data[1];

  if (g_type_is_a (owner_type, pspec->owner_type))
    {
      if (G_TYPE_IS_INTERFACE (pspec->owner_type))
        {
          slists[0] = g_slist_prepend (slists[0], pspec);
        }
      else
        {
          guint d = g_type_depth (pspec->owner_type);

          slists[d - 1] = g_slist_prepend (slists[d - 1], pspec);
        }
    }
}

/* We handle interfaces specially since we don't want to
 * count interface prerequsites like normal inheritance;
 * the property comes from the direct inheritance from
 * the prerequisite class, not from the interface that
 * prerequires it.
 * 
 * also 'depth' isn't a meaningful concept for interface
 * prerequites.
 */
static void
pool_depth_list_for_interface (gpointer key,
                               gpointer value,
                               gpointer user_data)
{
  GParamSpec *pspec = value;
  gpointer *data = user_data;
  GSList **slists = data[0];
  GType owner_type = (GType) data[1];

  if (pspec->owner_type == owner_type)
    slists[0] = g_slist_prepend (slists[0], pspec);
}

GParamSpec** /* free result */
g_param_spec_pool_list (GParamSpecPool *pool,
                        GType           owner_type,
                        guint          *n_pspecs_p)
{
  GParamSpec **pspecs, **p;
  GSList **slists, *node;
  gpointer data[2];
  guint d, i;

  g_return_val_if_fail (pool != NULL, NULL);
  g_return_val_if_fail (owner_type > 0, NULL);
  g_return_val_if_fail (n_pspecs_p != NULL, NULL);
  
  G_SLOCK (&pool->smutex);
  *n_pspecs_p = 0;
  d = g_type_depth (owner_type);
  slists = g_new0 (GSList*, d);
  data[0] = slists;
  data[1] = (gpointer) owner_type;

  g_hash_table_foreach (pool->hash_table,
                        G_TYPE_IS_INTERFACE (owner_type) ?
                           pool_depth_list_for_interface :
                           pool_depth_list,
                        &data);
  
  for (i = 0; i < d; i++)
    slists[i] = pspec_list_remove_overridden_and_redirected (slists[i], pool->hash_table, owner_type, n_pspecs_p);
  pspecs = g_new (GParamSpec*, *n_pspecs_p + 1);
  p = pspecs;
  for (i = 0; i < d; i++)
    {
      slists[i] = g_slist_sort (slists[i], pspec_compare_id);
      for (node = slists[i]; node; node = node->next)
        *p++ = node->data;
      g_slist_free (slists[i]);
    }
  *p++ = NULL;
  g_free (slists);
  G_SUNLOCK (&pool->smutex);

  return pspecs;
}


/* --- auxillary functions --- */
typedef struct
{
  /* class portion */
  GType           value_type;
  void          (*finalize)             (GParamSpec   *pspec);
  void          (*value_set_default)    (GParamSpec   *pspec,
                                         GValue       *value);
  gboolean      (*value_validate)       (GParamSpec   *pspec,
                                         GValue       *value);
  gint          (*values_cmp)           (GParamSpec   *pspec,
                                         const GValue *value1,
                                         const GValue *value2);
} ParamSpecClassInfo;

static void
param_spec_generic_class_init (gpointer g_class,
                               gpointer class_data)
{
  GParamSpecClass *class = g_class;
  ParamSpecClassInfo *info = class_data;

  class->value_type = info->value_type;
  if (info->finalize)
    class->finalize = info->finalize;                   /* optional */
  class->value_set_default = info->value_set_default;
  if (info->value_validate)
    class->value_validate = info->value_validate;       /* optional */
  class->values_cmp = info->values_cmp;
  g_free (class_data);
}

static void
default_value_set_default (GParamSpec *pspec,
                           GValue     *value)
{
  /* value is already zero initialized */
}

static gint
default_values_cmp (GParamSpec   *pspec,
                    const GValue *value1,
                    const GValue *value2)
{
  return memcmp (&value1->data, &value2->data, sizeof (value1->data));
}

GType
g_param_type_register_static (const gchar              *name,
                              const GParamSpecTypeInfo *pspec_info)
{
  GTypeInfo info = {
    sizeof (GParamSpecClass),      /* class_size */
    NULL,                          /* base_init */
    NULL,                          /* base_destroy */
    param_spec_generic_class_init, /* class_init */
    NULL,                          /* class_destroy */
    NULL,                          /* class_data */
    0,                             /* instance_size */
    16,                            /* n_preallocs */
    NULL,                          /* instance_init */
  };
  ParamSpecClassInfo *cinfo;

  g_return_val_if_fail (name != NULL, 0);
  g_return_val_if_fail (pspec_info != NULL, 0);
  g_return_val_if_fail (g_type_from_name (name) == 0, 0);
  g_return_val_if_fail (pspec_info->instance_size >= sizeof (GParamSpec), 0);
  g_return_val_if_fail (g_type_name (pspec_info->value_type) != NULL, 0);
  /* default: g_return_val_if_fail (pspec_info->value_set_default != NULL, 0); */
  /* optional: g_return_val_if_fail (pspec_info->value_validate != NULL, 0); */
  /* default: g_return_val_if_fail (pspec_info->values_cmp != NULL, 0); */

  info.instance_size = pspec_info->instance_size;
  info.n_preallocs = pspec_info->n_preallocs;
  info.instance_init = (GInstanceInitFunc) pspec_info->instance_init;
  cinfo = g_new (ParamSpecClassInfo, 1);
  cinfo->value_type = pspec_info->value_type;
  cinfo->finalize = pspec_info->finalize;
  cinfo->value_set_default = pspec_info->value_set_default ? pspec_info->value_set_default : default_value_set_default;
  cinfo->value_validate = pspec_info->value_validate;
  cinfo->values_cmp = pspec_info->values_cmp ? pspec_info->values_cmp : default_values_cmp;
  info.class_data = cinfo;

  return g_type_register_static (G_TYPE_PARAM, name, &info, 0);
}

void
g_value_set_param (GValue     *value,
                   GParamSpec *param)
{
  g_return_if_fail (G_VALUE_HOLDS_PARAM (value));
  if (param)
    g_return_if_fail (G_IS_PARAM_SPEC (param));

  if (value->data[0].v_pointer)
    g_param_spec_unref (value->data[0].v_pointer);
  value->data[0].v_pointer = param;
  if (value->data[0].v_pointer)
    g_param_spec_ref (value->data[0].v_pointer);
}

void
g_value_set_param_take_ownership (GValue     *value,
                                  GParamSpec *param)
{
  g_value_take_param (value, param);
}

void
g_value_take_param (GValue     *value,
                    GParamSpec *param)
{
  g_return_if_fail (G_VALUE_HOLDS_PARAM (value));
  if (param)
    g_return_if_fail (G_IS_PARAM_SPEC (param));

  if (value->data[0].v_pointer)
    g_param_spec_unref (value->data[0].v_pointer);
  value->data[0].v_pointer = param; /* we take over the reference count */
}

GParamSpec*
g_value_get_param (const GValue *value)
{
  g_return_val_if_fail (G_VALUE_HOLDS_PARAM (value), NULL);

  return value->data[0].v_pointer;
}

GParamSpec*
g_value_dup_param (const GValue *value)
{
  g_return_val_if_fail (G_VALUE_HOLDS_PARAM (value), NULL);

  return value->data[0].v_pointer ? g_param_spec_ref (value->data[0].v_pointer) : NULL;
}