gobject/gclosure.h

   1 /* GObject - GLib Type, Object, Parameter and Signal Library
   2  * Copyright (C) 2000-2001 Red Hat, Inc.
   3  * Copyright (C) 2005 Imendio AB
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18 #ifndef __G_CLOSURE_H__
  19 #define __G_CLOSURE_H__
  20
  21 #if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
  22 #error "Only <glib-object.h> can be included directly."
  23 #endif
  24
  25 #include        <gobject/gtype.h>
  26
  27 G_BEGIN_DECLS
  28
  29 /* --- defines --- */
  30 /**
  31  * G_CLOSURE_NEEDS_MARSHAL:
  32  * @closure: a #GClosure
  33  *
  34  * Check if the closure still needs a marshaller. See g_closure_set_marshal().
  35  *
  36  * Returns: %TRUE if a #GClosureMarshal marshaller has not yet been set on
  37  * @closure.
  38  */
  39 #define G_CLOSURE_NEEDS_MARSHAL(closure) (((GClosure*) (closure))->marshal == NULL)
  40 /**
  41  * G_CLOSURE_N_NOTIFIERS:
  42  * @cl: a #GClosure
  43  *
  44  * Get the total number of notifiers connected with the closure @cl.
  45  * The count includes the meta marshaller, the finalize and invalidate notifiers
  46  * and the marshal guards. Note that each guard counts as two notifiers.
  47  * See g_closure_set_meta_marshal(), g_closure_add_finalize_notifier(),
  48  * g_closure_add_invalidate_notifier() and g_closure_add_marshal_guards().
  49  *
  50  * Returns: number of notifiers
  51  */
  52 #define G_CLOSURE_N_NOTIFIERS(cl)        (((cl)->n_guards << 1L) + \
  53                                           (cl)->n_fnotifiers + (cl)->n_inotifiers)
  54 /**
  55  * G_CCLOSURE_SWAP_DATA:
  56  * @cclosure: a #GCClosure
  57  *
  58  * Checks whether the user data of the #GCClosure should be passed as the
  59  * first parameter to the callback. See g_cclosure_new_swap().
  60  *
  61  * Returns: %TRUE if data has to be swapped.
  62  */
  63 #define G_CCLOSURE_SWAP_DATA(cclosure)   (((GClosure*) (cclosure))->derivative_flag)
  64 /**
  65  * G_CALLBACK:
  66  * @f: a function pointer.
  67  *
  68  * Cast a function pointer to a #GCallback.
  69  */
  70 #define G_CALLBACK(f)                    ((GCallback) (f))
  71
  72
  73 /* -- typedefs --- */
  74 typedef struct _GClosure                 GClosure;
  75 typedef struct _GClosureNotifyData       GClosureNotifyData;
  76
  77 /**
  78  * GCallback:
  79  *
  80  * The type used for callback functions in structure definitions and function
  81  * signatures. This doesn't mean that all callback functions must take no
  82  * parameters and return void. The required signature of a callback function
  83  * is determined by the context in which is used (e.g. the signal to which it
  84  * is connected). Use G_CALLBACK() to cast the callback function to a #GCallback.
  85  */
  86 typedef void  (*GCallback)              (void);
  87 /**
  88  * GClosureNotify:
  89  * @data: data specified when registering the notification callback
  90  * @closure: the #GClosure on which the notification is emitted
  91  *
  92  * The type used for the various notification callbacks which can be registered
  93  * on closures.
  94  */
  95 typedef void  (*GClosureNotify)         (gpointer        data,
  96                                          GClosure       *closure);
  97 /**
  98  * GClosureMarshal:
  99  * @closure: the #GClosure to which the marshaller belongs
 100  * @return_value: (allow-none): a #GValue to store the return
 101  *  value. May be %NULL if the callback of @closure doesn't return a
 102  *  value.
 103  * @n_param_values: the length of the @param_values array
 104  * @param_values: (array length=n_param_values): an array of
 105  *  #GValue<!-- -->s holding the arguments on which to invoke the
 106  *  callback of @closure
 107  * @invocation_hint: (allow-none): the invocation hint given as the
 108  *  last argument to g_closure_invoke()
 109  * @marshal_data: (allow-none): additional data specified when
 110  *  registering the marshaller, see g_closure_set_marshal() and
 111  *  g_closure_set_meta_marshal()
 112  *
 113  * The type used for marshaller functions.
 114  */
 115 typedef void  (*GClosureMarshal)        (GClosure       *closure,
 116                                          GValue         *return_value,
 117                                          guint           n_param_values,
 118                                          const GValue   *param_values,
 119                                          gpointer        invocation_hint,
 120                                          gpointer        marshal_data);
 121
 122 typedef void (* GVaClosureMarshal) (GClosure *closure,
 123                                     GValue   *return_value,
 124                                     gpointer  instance,
 125                                     va_list   args,
 126                                     gpointer  marshal_data,
 127                                     int       n_params,
 128                                     GType    *param_types);
 129
 130 /**
 131  * GCClosure:
 132  * @closure: the #GClosure
 133  * @callback: the callback function
 134  *
 135  * A #GCClosure is a specialization of #GClosure for C function callbacks.
 136  */
 137 typedef struct _GCClosure                GCClosure;
 138
 139
 140 /* --- structures --- */
 141 struct _GClosureNotifyData
 142 {
 143   gpointer       data;
 144   GClosureNotify notify;
 145 };
 146 /**
 147  * GClosure:
 148  * @in_marshal: Indicates whether the closure is currently being invoked with
 149  *  g_closure_invoke()
 150  * @is_invalid: Indicates whether the closure has been invalidated by
 151  *  g_closure_invalidate()
 152  *
 153  * A #GClosure represents a callback supplied by the programmer.
 154  */
 155 struct _GClosure
 156 {
 157   /*< private >*/
 158   volatile              guint    ref_count : 15;
 159   /* meta_marshal is not used anymore but must be zero for historical reasons
 160      as it was exposed in the G_CLOSURE_N_NOTIFIERS macro */
 161   volatile              guint    meta_marshal_nouse : 1;
 162   volatile              guint    n_guards : 1;
 163   volatile              guint    n_fnotifiers : 2;      /* finalization notifiers */
 164   volatile              guint    n_inotifiers : 8;      /* invalidation notifiers */
 165   volatile              guint    in_inotify : 1;
 166   volatile              guint    floating : 1;
 167   /*< protected >*/
 168   volatile              guint    derivative_flag : 1;
 169   /*< public >*/
 170   volatile              guint    in_marshal : 1;
 171   volatile              guint    is_invalid : 1;
 172
 173   /*< private >*/       void   (*marshal)  (GClosure       *closure,
 174                                             GValue /*out*/ *return_value,
 175                                             guint           n_param_values,
 176                                             const GValue   *param_values,
 177                                             gpointer        invocation_hint,
 178                                             gpointer        marshal_data);
 179   /*< protected >*/     gpointer data;
 180
 181   /*< private >*/       GClosureNotifyData *notifiers;
 182
 183   /* invariants/constrains:
 184    * - ->marshal and ->data are _invalid_ as soon as ->is_invalid==TRUE
 185    * - invocation of all inotifiers occours prior to fnotifiers
 186    * - order of inotifiers is random
 187    *   inotifiers may _not_ free/invalidate parameter values (e.g. ->data)
 188    * - order of fnotifiers is random
 189    * - each notifier may only be removed before or during its invocation
 190    * - reference counting may only happen prior to fnotify invocation
 191    *   (in that sense, fnotifiers are really finalization handlers)
 192    */
 193 };
 194 /* closure for C function calls, callback() is the user function
 195  */
 196 struct _GCClosure
 197 {
 198   GClosure      closure;
 199   gpointer      callback;
 200 };
 201
 202
 203 /* --- prototypes --- */
 204 GLIB_AVAILABLE_IN_ALL
 205 GClosure* g_cclosure_new                        (GCallback      callback_func,
 206                                                  gpointer       user_data,
 207                                                  GClosureNotify destroy_data);
 208 GLIB_AVAILABLE_IN_ALL
 209 GClosure* g_cclosure_new_swap                   (GCallback      callback_func,
 210                                                  gpointer       user_data,
 211                                                  GClosureNotify destroy_data);
 212 GLIB_AVAILABLE_IN_ALL
 213 GClosure* g_signal_type_cclosure_new            (GType          itype,
 214                                                  guint          struct_offset);
 215
 216
 217 /* --- prototypes --- */
 218 GLIB_AVAILABLE_IN_ALL
 219 GClosure* g_closure_ref                         (GClosure       *closure);
 220 GLIB_AVAILABLE_IN_ALL
 221 void      g_closure_sink                        (GClosure       *closure);
 222 GLIB_AVAILABLE_IN_ALL
 223 void      g_closure_unref                       (GClosure       *closure);
 224 /* intimidating */
 225 GLIB_AVAILABLE_IN_ALL
 226 GClosure* g_closure_new_simple                  (guint           sizeof_closure,
 227                                                  gpointer        data);
 228 GLIB_AVAILABLE_IN_ALL
 229 void      g_closure_add_finalize_notifier       (GClosure       *closure,
 230                                                  gpointer        notify_data,
 231                                                  GClosureNotify  notify_func);
 232 GLIB_AVAILABLE_IN_ALL
 233 void      g_closure_remove_finalize_notifier    (GClosure       *closure,
 234                                                  gpointer        notify_data,
 235                                                  GClosureNotify  notify_func);
 236 GLIB_AVAILABLE_IN_ALL
 237 void      g_closure_add_invalidate_notifier     (GClosure       *closure,
 238                                                  gpointer        notify_data,
 239                                                  GClosureNotify  notify_func);
 240 GLIB_AVAILABLE_IN_ALL
 241 void      g_closure_remove_invalidate_notifier  (GClosure       *closure,
 242                                                  gpointer        notify_data,
 243                                                  GClosureNotify  notify_func);
 244 GLIB_AVAILABLE_IN_ALL
 245 void      g_closure_add_marshal_guards          (GClosure       *closure,
 246                                                  gpointer        pre_marshal_data,
 247                                                  GClosureNotify  pre_marshal_notify,
 248                                                  gpointer        post_marshal_data,
 249                                                  GClosureNotify  post_marshal_notify);
 250 GLIB_AVAILABLE_IN_ALL
 251 void      g_closure_set_marshal                 (GClosure       *closure,
 252                                                  GClosureMarshal marshal);
 253 GLIB_AVAILABLE_IN_ALL
 254 void      g_closure_set_meta_marshal            (GClosure       *closure,
 255                                                  gpointer        marshal_data,
 256                                                  GClosureMarshal meta_marshal);
 257 GLIB_AVAILABLE_IN_ALL
 258 void      g_closure_invalidate                  (GClosure       *closure);
 259 GLIB_AVAILABLE_IN_ALL
 260 void      g_closure_invoke                      (GClosure       *closure,
 261                                                  GValue /*out*/ *return_value,
 262                                                  guint           n_param_values,
 263                                                  const GValue   *param_values,
 264                                                  gpointer        invocation_hint);
 265
 266 /* FIXME:
 267    OK:  data_object::destroy            -> closure_invalidate();
 268    MIS: closure_invalidate()            -> disconnect(closure);
 269    MIS: disconnect(closure)             -> (unlink) closure_unref();
 270    OK:  closure_finalize()              -> g_free (data_string);
 271
 272    random remarks:
 273    - need marshaller repo with decent aliasing to base types
 274    - provide marshaller collection, virtually covering anything out there
 275 */
 276
 277 GLIB_AVAILABLE_IN_ALL
 278 void g_cclosure_marshal_generic (GClosure     *closure,
 279                                  GValue       *return_gvalue,
 280                                  guint         n_param_values,
 281                                  const GValue *param_values,
 282                                  gpointer      invocation_hint,
 283                                  gpointer      marshal_data);
 284
 285 GLIB_AVAILABLE_IN_ALL
 286 void g_cclosure_marshal_generic_va (GClosure *closure,
 287                                     GValue   *return_value,
 288                                     gpointer  instance,
 289                                     va_list   args_list,
 290                                     gpointer  marshal_data,
 291                                     int       n_params,
 292                                     GType    *param_types);
 293
 294
 295 G_END_DECLS
 296
 297 #endif /* __G_CLOSURE_H__ */