gdataset.c

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/* GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * gdataset.c: Generic dataset mechanism, similar to GtkObject data.
 * Copyright (C) 1998 Tim Janik
 *
 * 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.
 */

/*
 * Modified by the GLib Team and others 1997-1999.  See the AUTHORS
 * file for a list of people on the GLib Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GLib at ftp://ftp.gtk.org/pub/gtk/. 
 */

/* 
 * MT safe ; FIXME: might still freeze, watch out, not thoroughly
 * looked at yet.  
 */

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



/* --- defines --- */
#define G_QUARK_BLOCK_SIZE                      (512)
#define G_DATA_MEM_CHUNK_PREALLOC               (128)
#define G_DATA_CACHE_MAX                        (512)
#define G_DATASET_MEM_CHUNK_PREALLOC            (32)


/* --- structures --- */
typedef struct _GDataset GDataset;
struct _GData
{
  GData *next;
  GQuark id;
  gpointer data;
  GDestroyNotify destroy_func;
};

struct _GDataset
{
  gconstpointer location;
  GData        *datalist;
};


/* --- prototypes --- */
static inline GDataset* g_dataset_lookup                (gconstpointer    dataset_location);
static inline void      g_datalist_clear_i              (GData          **datalist);
static void             g_dataset_destroy_internal      (GDataset        *dataset);
static inline void      g_data_set_internal             (GData          **datalist,
                                                         GQuark           key_id,
                                                         gpointer         data,
                                                         GDestroyNotify   destroy_func,
                                                         GDataset        *dataset);
static void             g_data_initialize               (void);
static inline GQuark    g_quark_new                     (gchar          *string);


/* --- variables --- */
G_LOCK_DEFINE_STATIC (g_dataset_global);
static GHashTable   *g_dataset_location_ht = NULL;
static GDataset     *g_dataset_cached = NULL; /* should this be
                                                 threadspecific? */
static GMemChunk    *g_dataset_mem_chunk = NULL;
static GMemChunk    *g_data_mem_chunk = NULL;
static GData        *g_data_cache = NULL;
static guint         g_data_cache_length = 0;

G_LOCK_DEFINE_STATIC (g_quark_global);
static GHashTable   *g_quark_ht = NULL;
static gchar       **g_quarks = NULL;
static GQuark        g_quark_seq_id = 0;


/* --- functions --- */

/* HOLDS: g_dataset_global_lock */
static inline void
g_datalist_clear_i (GData **datalist)
{
  register GData *list;
  
  /* unlink *all* items before walking their destructors
   */
  list = *datalist;
  *datalist = NULL;
  
  while (list)
    {
      register GData *prev;
      
      prev = list;
      list = prev->next;
      
      if (prev->destroy_func)
        {
          G_UNLOCK (g_dataset_global);
          prev->destroy_func (prev->data);
          G_LOCK (g_dataset_global);
        }
      
      if (g_data_cache_length < G_DATA_CACHE_MAX)
        {
          prev->next = g_data_cache;
          g_data_cache = prev;
          g_data_cache_length++;
        }
      else
        g_mem_chunk_free (g_data_mem_chunk, prev);
    }
}

void
g_datalist_clear (GData **datalist)
{
  g_return_if_fail (datalist != NULL);
  
  G_LOCK (g_dataset_global);
  if (!g_dataset_location_ht)
    g_data_initialize ();

  while (*datalist)
    g_datalist_clear_i (datalist);
  G_UNLOCK (g_dataset_global);
}

/* HOLDS: g_dataset_global_lock */
static inline GDataset*
g_dataset_lookup (gconstpointer dataset_location)
{
  register GDataset *dataset;
  
  if (g_dataset_cached && g_dataset_cached->location == dataset_location)
    return g_dataset_cached;
  
  dataset = g_hash_table_lookup (g_dataset_location_ht, dataset_location);
  if (dataset)
    g_dataset_cached = dataset;
  
  return dataset;
}

/* HOLDS: g_dataset_global_lock */
static void
g_dataset_destroy_internal (GDataset *dataset)
{
  register gconstpointer dataset_location;
  
  dataset_location = dataset->location;
  while (dataset)
    {
      if (!dataset->datalist)
        {
          if (dataset == g_dataset_cached)
            g_dataset_cached = NULL;
          g_hash_table_remove (g_dataset_location_ht, dataset_location);
          g_mem_chunk_free (g_dataset_mem_chunk, dataset);
          break;
        }
      
      g_datalist_clear_i (&dataset->datalist);
      dataset = g_dataset_lookup (dataset_location);
    }
}

void
g_dataset_destroy (gconstpointer  dataset_location)
{
  g_return_if_fail (dataset_location != NULL);
  
  G_LOCK (g_dataset_global);
  if (g_dataset_location_ht)
    {
      register GDataset *dataset;

      dataset = g_dataset_lookup (dataset_location);
      if (dataset)
        g_dataset_destroy_internal (dataset);
    }
  G_UNLOCK (g_dataset_global);
}

/* HOLDS: g_dataset_global_lock */
static inline void
g_data_set_internal (GData        **datalist,
                     GQuark         key_id,
                     gpointer       data,
                     GDestroyNotify destroy_func,
                     GDataset      *dataset)
{
  register GData *list;
  
  list = *datalist;
  if (!data)
    {
      register GData *prev;
      
      prev = NULL;
      while (list)
        {
          if (list->id == key_id)
            {
              if (prev)
                prev->next = list->next;
              else
                {
                  *datalist = list->next;
                  
                  /* the dataset destruction *must* be done
                   * prior to invokation of the data destroy function
                   */
                  if (!*datalist && dataset)
                    g_dataset_destroy_internal (dataset);
                }
              
              /* the GData struct *must* already be unlinked
               * when invoking the destroy function.
               * we use (data==NULL && destroy_func!=NULL) as
               * a special hint combination to "steal"
               * data without destroy notification
               */
              if (list->destroy_func && !destroy_func)
                {
                  G_UNLOCK (g_dataset_global);
                  list->destroy_func (list->data);
                  G_LOCK (g_dataset_global);
                }
              
              if (g_data_cache_length < G_DATA_CACHE_MAX)
                {
                  list->next = g_data_cache;
                  g_data_cache = list;
                  g_data_cache_length++;
                }
              else
                g_mem_chunk_free (g_data_mem_chunk, list);
              
              return;
            }
          
          prev = list;
          list = list->next;
        }
    }
  else
    {
      while (list)
        {
          if (list->id == key_id)
            {
              if (!list->destroy_func)
                {
                  list->data = data;
                  list->destroy_func = destroy_func;
                }
              else
                {
                  register GDestroyNotify dfunc;
                  register gpointer ddata;
                  
                  dfunc = list->destroy_func;
                  ddata = list->data;
                  list->data = data;
                  list->destroy_func = destroy_func;
                  
                  /* we need to have updated all structures prior to
                   * invokation of the destroy function
                   */
                  G_UNLOCK (g_dataset_global);
                  dfunc (ddata);
                  G_LOCK (g_dataset_global);
                }
              
              return;
            }
          
          list = list->next;
        }
      
      if (g_data_cache)
        {
          list = g_data_cache;
          g_data_cache = list->next;
          g_data_cache_length--;
        }
      else
        list = g_chunk_new (GData, g_data_mem_chunk);
      list->next = *datalist;
      list->id = key_id;
      list->data = data;
      list->destroy_func = destroy_func;
      *datalist = list;
    }
}

void
g_dataset_id_set_data_full (gconstpointer  dataset_location,
                            GQuark         key_id,
                            gpointer       data,
                            GDestroyNotify destroy_func)
{
  register GDataset *dataset;
  
  g_return_if_fail (dataset_location != NULL);
  if (!data)
    g_return_if_fail (destroy_func == NULL);
  if (!key_id)
    {
      if (data)
        g_return_if_fail (key_id > 0);
      else
        return;
    }
  
  G_LOCK (g_dataset_global);
  if (!g_dataset_location_ht)
    g_data_initialize ();
 
  dataset = g_dataset_lookup (dataset_location);
  if (!dataset)
    {
      dataset = g_chunk_new (GDataset, g_dataset_mem_chunk);
      dataset->location = dataset_location;
      g_datalist_init (&dataset->datalist);
      g_hash_table_insert (g_dataset_location_ht, 
                           (gpointer) dataset->location,
                           dataset);
    }
  
  g_data_set_internal (&dataset->datalist, key_id, data, destroy_func, dataset);
  G_UNLOCK (g_dataset_global);
}

void
g_datalist_id_set_data_full (GData        **datalist,
                             GQuark         key_id,
                             gpointer       data,
                             GDestroyNotify destroy_func)
{
  g_return_if_fail (datalist != NULL);
  if (!data)
    g_return_if_fail (destroy_func == NULL);
  if (!key_id)
    {
      if (data)
        g_return_if_fail (key_id > 0);
      else
        return;
    }

  G_LOCK (g_dataset_global);
  if (!g_dataset_location_ht)
    g_data_initialize ();
  
  g_data_set_internal (datalist, key_id, data, destroy_func, NULL);
  G_UNLOCK (g_dataset_global);
}

void
g_dataset_id_remove_no_notify (gconstpointer  dataset_location,
                               GQuark         key_id)
{
  g_return_if_fail (dataset_location != NULL);
  
  G_LOCK (g_dataset_global);
  if (key_id && g_dataset_location_ht)
    {
      GDataset *dataset;
  
      dataset = g_dataset_lookup (dataset_location);
      if (dataset)
        g_data_set_internal (&dataset->datalist, key_id, NULL, (GDestroyNotify) 42, dataset);
    } 
  G_UNLOCK (g_dataset_global);
}

void
g_datalist_id_remove_no_notify (GData   **datalist,
                                GQuark    key_id)
{
  g_return_if_fail (datalist != NULL);

  G_LOCK (g_dataset_global);
  if (key_id && g_dataset_location_ht)
    g_data_set_internal (datalist, key_id, NULL, (GDestroyNotify) 42, NULL);
  G_UNLOCK (g_dataset_global);
}

gpointer
g_dataset_id_get_data (gconstpointer  dataset_location,
                       GQuark         key_id)
{
  g_return_val_if_fail (dataset_location != NULL, NULL);
  
  G_LOCK (g_dataset_global);
  if (key_id && g_dataset_location_ht)
    {
      register GDataset *dataset;
      
      dataset = g_dataset_lookup (dataset_location);
      if (dataset)
        {
          register GData *list;
          
          for (list = dataset->datalist; list; list = list->next)
            if (list->id == key_id)
              {
                G_UNLOCK (g_dataset_global);
                return list->data;
              }
        }
    }
  G_UNLOCK (g_dataset_global);
 
  return NULL;
}

gpointer
g_datalist_id_get_data (GData    **datalist,
                        GQuark     key_id)
{
  g_return_val_if_fail (datalist != NULL, NULL);
  
  if (key_id)
    {
      register GData *list;
      
      for (list = *datalist; list; list = list->next)
        if (list->id == key_id)
          return list->data;
    }
  
  return NULL;
}

void
g_dataset_foreach (gconstpointer    dataset_location,
                   GDataForeachFunc func,
                   gpointer         user_data)
{
  register GDataset *dataset;
  
  g_return_if_fail (dataset_location != NULL);
  g_return_if_fail (func != NULL);

  G_LOCK (g_dataset_global);
  if (g_dataset_location_ht)
    {
      dataset = g_dataset_lookup (dataset_location);
      G_UNLOCK (g_dataset_global);
      if (dataset)
        {
          register GData *list;
          
          for (list = dataset->datalist; list; list = list->next)
              func (list->id, list->data, user_data);
        }
    }
  else
    {
      G_UNLOCK (g_dataset_global);
    }
}

void
g_datalist_foreach (GData          **datalist,
                    GDataForeachFunc func,
                    gpointer         user_data)
{
  register GData *list;

  g_return_if_fail (datalist != NULL);
  g_return_if_fail (func != NULL);
  
  for (list = *datalist; list; list = list->next)
    func (list->id, list->data, user_data);
}

void
g_datalist_init (GData **datalist)
{
  g_return_if_fail (datalist != NULL);
  
  *datalist = NULL;
}

/* HOLDS: g_dataset_global_lock */
static void
g_data_initialize (void)
{
  g_return_if_fail (g_dataset_location_ht == NULL);

  g_dataset_location_ht = g_hash_table_new (g_direct_hash, NULL);
  g_dataset_cached = NULL;
  g_dataset_mem_chunk =
    g_mem_chunk_new ("GDataset MemChunk",
                     sizeof (GDataset),
                     sizeof (GDataset) * G_DATASET_MEM_CHUNK_PREALLOC,
                     G_ALLOC_AND_FREE);
  g_data_mem_chunk =
    g_mem_chunk_new ("GData MemChunk",
                     sizeof (GData),
                     sizeof (GData) * G_DATA_MEM_CHUNK_PREALLOC,
                     G_ALLOC_AND_FREE);
}

GQuark
g_quark_try_string (const gchar *string)
{
  GQuark quark = 0;
  g_return_val_if_fail (string != NULL, 0);
  
  G_LOCK (g_quark_global);
  if (g_quark_ht)
    quark = GPOINTER_TO_UINT (g_hash_table_lookup (g_quark_ht, string));
  G_UNLOCK (g_quark_global);
  
  return quark;
}

GQuark
g_quark_from_string (const gchar *string)
{
  GQuark quark;
  
  g_return_val_if_fail (string != NULL, 0);
  
  G_LOCK (g_quark_global);
  if (g_quark_ht)
    quark = (gulong) g_hash_table_lookup (g_quark_ht, string);
  else
    {
      g_quark_ht = g_hash_table_new (g_str_hash, g_str_equal);
      quark = 0;
    }
  
  if (!quark)
    quark = g_quark_new (g_strdup (string));
  G_UNLOCK (g_quark_global);
  
  return quark;
}

GQuark
g_quark_from_static_string (const gchar *string)
{
  GQuark quark;
  
  g_return_val_if_fail (string != NULL, 0);
  
  G_LOCK (g_quark_global);
  if (g_quark_ht)
    quark = (gulong) g_hash_table_lookup (g_quark_ht, string);
  else
    {
      g_quark_ht = g_hash_table_new (g_str_hash, g_str_equal);
      quark = 0;
    }

  if (!quark)
    quark = g_quark_new ((gchar*) string);
  G_UNLOCK (g_quark_global);
 
  return quark;
}

gchar*
g_quark_to_string (GQuark quark)
{
  gchar* result = NULL;
  G_LOCK (g_quark_global);
  if (quark > 0 && quark <= g_quark_seq_id)
    result = g_quarks[quark - 1];
  G_UNLOCK (g_quark_global);

  return result;
}

/* HOLDS: g_quark_global_lock */
static inline GQuark
g_quark_new (gchar *string)
{
  GQuark quark;
  
  if (g_quark_seq_id % G_QUARK_BLOCK_SIZE == 0)
    g_quarks = g_renew (gchar*, g_quarks, g_quark_seq_id + G_QUARK_BLOCK_SIZE);
  
  g_quarks[g_quark_seq_id] = string;
  g_quark_seq_id++;
  quark = g_quark_seq_id;
  g_hash_table_insert (g_quark_ht, string, GUINT_TO_POINTER (quark));
  
  return quark;
}

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