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 2.1 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: (nullable): 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  *  #GValues holding the arguments on which to invoke the
 106  *  callback of @closure
 107  * @invocation_hint: (nullable): the invocation hint given as the
 108  *  last argument to g_closure_invoke()
 109  * @marshal_data: (nullable): 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 /**
 123  * GVaClosureMarshal:
 124  * @closure: the #GClosure to which the marshaller belongs
 125  * @return_value: (nullable): a #GValue to store the return
 126  *  value. May be %NULL if the callback of @closure doesn't return a
 127  *  value.
 128  * @instance: (type GObject.TypeInstance): the instance on which the closure is
 129  *  invoked.
 130  * @args: va_list of arguments to be passed to the closure.
 131  * @marshal_data: (nullable): additional data specified when
 132  *  registering the marshaller, see g_closure_set_marshal() and
 133  *  g_closure_set_meta_marshal()
 134  * @n_params: the length of the @param_types array
 135  * @param_types: (array length=n_params): the #GType of each argument from
 136  *  @args.
 137  *
 138  * This is the signature of va_list marshaller functions, an optional
 139  * marshaller that can be used in some situations to avoid
 140  * marshalling the signal argument into GValues.
 141  */
 142 typedef void (* GVaClosureMarshal) (GClosure *closure,
 143                                     GValue   *return_value,
 144                                     gpointer  instance,
 145                                     va_list   args,
 146                                     gpointer  marshal_data,
 147                                     int       n_params,
 148                                     GType    *param_types);
 149
 150 /**
 151  * GCClosure:
 152  * @closure: the #GClosure
 153  * @callback: the callback function
 154  *
 155  * A #GCClosure is a specialization of #GClosure for C function callbacks.
 156  */
 157 typedef struct _GCClosure                GCClosure;
 158
 159
 160 /* --- structures --- */
 161 struct _GClosureNotifyData
 162 {
 163   gpointer       data;
 164   GClosureNotify notify;
 165 };
 166 /**
 167  * GClosure:
 168  * @in_marshal: Indicates whether the closure is currently being invoked with
 169  *  g_closure_invoke()
 170  * @is_invalid: Indicates whether the closure has been invalidated by
 171  *  g_closure_invalidate()
 172  *
 173  * A #GClosure represents a callback supplied by the programmer.
 174  */
 175 struct _GClosure
 176 {
 177   /*< private >*/
 178   volatile              guint    ref_count : 15;
 179   /* meta_marshal is not used anymore but must be zero for historical reasons
 180      as it was exposed in the G_CLOSURE_N_NOTIFIERS macro */
 181   volatile              guint    meta_marshal_nouse : 1;
 182   volatile              guint    n_guards : 1;
 183   volatile              guint    n_fnotifiers : 2;      /* finalization notifiers */
 184   volatile              guint    n_inotifiers : 8;      /* invalidation notifiers */
 185   volatile              guint    in_inotify : 1;
 186   volatile              guint    floating : 1;
 187   /*< protected >*/
 188   volatile              guint    derivative_flag : 1;
 189   /*< public >*/
 190   volatile              guint    in_marshal : 1;
 191   volatile              guint    is_invalid : 1;
 192
 193   /*< private >*/       void   (*marshal)  (GClosure       *closure,
 194                                             GValue /*out*/ *return_value,
 195                                             guint           n_param_values,
 196                                             const GValue   *param_values,
 197                                             gpointer        invocation_hint,
 198                                             gpointer        marshal_data);
 199   /*< protected >*/     gpointer data;
 200
 201   /*< private >*/       GClosureNotifyData *notifiers;
 202
 203   /* invariants/constrains:
 204    * - ->marshal and ->data are _invalid_ as soon as ->is_invalid==TRUE
 205    * - invocation of all inotifiers occours prior to fnotifiers
 206    * - order of inotifiers is random
 207    *   inotifiers may _not_ free/invalidate parameter values (e.g. ->data)
 208    * - order of fnotifiers is random
 209    * - each notifier may only be removed before or during its invocation
 210    * - reference counting may only happen prior to fnotify invocation
 211    *   (in that sense, fnotifiers are really finalization handlers)
 212    */
 213 };
 214 /* closure for C function calls, callback() is the user function
 215  */
 216 struct _GCClosure
 217 {
 218   GClosure      closure;
 219   gpointer      callback;
 220 };
 221
 222
 223 /* --- prototypes --- */
 224 GLIB_AVAILABLE_IN_ALL
 225 GClosure* g_cclosure_new                        (GCallback      callback_func,
 226                                                  gpointer       user_data,
 227                                                  GClosureNotify destroy_data);
 228 GLIB_AVAILABLE_IN_ALL
 229 GClosure* g_cclosure_new_swap                   (GCallback      callback_func,
 230                                                  gpointer       user_data,
 231                                                  GClosureNotify destroy_data);
 232 GLIB_AVAILABLE_IN_ALL
 233 GClosure* g_signal_type_cclosure_new            (GType          itype,
 234                                                  guint          struct_offset);
 235
 236
 237 /* --- prototypes --- */
 238 GLIB_AVAILABLE_IN_ALL
 239 GClosure* g_closure_ref                         (GClosure       *closure);
 240 GLIB_AVAILABLE_IN_ALL
 241 void      g_closure_sink                        (GClosure       *closure);
 242 GLIB_AVAILABLE_IN_ALL
 243 void      g_closure_unref                       (GClosure       *closure);
 244 /* intimidating */
 245 GLIB_AVAILABLE_IN_ALL
 246 GClosure* g_closure_new_simple                  (guint           sizeof_closure,
 247                                                  gpointer        data);
 248 GLIB_AVAILABLE_IN_ALL
 249 void      g_closure_add_finalize_notifier       (GClosure       *closure,
 250                                                  gpointer        notify_data,
 251                                                  GClosureNotify  notify_func);
 252 GLIB_AVAILABLE_IN_ALL
 253 void      g_closure_remove_finalize_notifier    (GClosure       *closure,
 254                                                  gpointer        notify_data,
 255                                                  GClosureNotify  notify_func);
 256 GLIB_AVAILABLE_IN_ALL
 257 void      g_closure_add_invalidate_notifier     (GClosure       *closure,
 258                                                  gpointer        notify_data,
 259                                                  GClosureNotify  notify_func);
 260 GLIB_AVAILABLE_IN_ALL
 261 void      g_closure_remove_invalidate_notifier  (GClosure       *closure,
 262                                                  gpointer        notify_data,
 263                                                  GClosureNotify  notify_func);
 264 GLIB_AVAILABLE_IN_ALL
 265 void      g_closure_add_marshal_guards          (GClosure       *closure,
 266                                                  gpointer        pre_marshal_data,
 267                                                  GClosureNotify  pre_marshal_notify,
 268                                                  gpointer        post_marshal_data,
 269                                                  GClosureNotify  post_marshal_notify);
 270 GLIB_AVAILABLE_IN_ALL
 271 void      g_closure_set_marshal                 (GClosure       *closure,
 272                                                  GClosureMarshal marshal);
 273 GLIB_AVAILABLE_IN_ALL
 274 void      g_closure_set_meta_marshal            (GClosure       *closure,
 275                                                  gpointer        marshal_data,
 276                                                  GClosureMarshal meta_marshal);
 277 GLIB_AVAILABLE_IN_ALL
 278 void      g_closure_invalidate                  (GClosure       *closure);
 279 GLIB_AVAILABLE_IN_ALL
 280 void      g_closure_invoke                      (GClosure       *closure,
 281                                                  GValue /*out*/ *return_value,
 282                                                  guint           n_param_values,
 283                                                  const GValue   *param_values,
 284                                                  gpointer        invocation_hint);
 285
 286 /* FIXME:
 287    OK:  data_object::destroy            -> closure_invalidate();
 288    MIS: closure_invalidate()            -> disconnect(closure);
 289    MIS: disconnect(closure)             -> (unlink) closure_unref();
 290    OK:  closure_finalize()              -> g_free (data_string);
 291
 292    random remarks:
 293    - need marshaller repo with decent aliasing to base types
 294    - provide marshaller collection, virtually covering anything out there
 295 */
 296
 297 GLIB_AVAILABLE_IN_ALL
 298 void g_cclosure_marshal_generic (GClosure     *closure,
 299                                  GValue       *return_gvalue,
 300                                  guint         n_param_values,
 301                                  const GValue *param_values,
 302                                  gpointer      invocation_hint,
 303                                  gpointer      marshal_data);
 304
 305 GLIB_AVAILABLE_IN_ALL
 306 void g_cclosure_marshal_generic_va (GClosure *closure,
 307                                     GValue   *return_value,
 308                                     gpointer  instance,
 309                                     va_list   args_list,
 310                                     gpointer  marshal_data,
 311                                     int       n_params,
 312                                     GType    *param_types);
 313
 314
 315 G_END_DECLS
 316
 317 #endif /* __G_CLOSURE_H__ */