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, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  */
  20 #if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
  21 #error "Only <glib-object.h> can be included directly."
  22 #endif
  23
  24 #ifndef __G_CLOSURE_H__
  25 #define __G_CLOSURE_H__
  26
  27 #include        <gobject/gtype.h>
  28
  29 G_BEGIN_DECLS
  30
  31 /* --- defines --- */
  32 /**
  33  * G_CLOSURE_NEEDS_MARSHAL:
  34  * @closure: a #GClosure
  35  *
  36  * Check if the closure still needs a marshaller. See g_closure_set_marshal().
  37  *
  38  * Returns: %TRUE if a #GClosureMarshal marshaller has not yet been set on
  39  * @closure.
  40  */
  41 #define G_CLOSURE_NEEDS_MARSHAL(closure) (((GClosure*) (closure))->marshal == NULL)
  42 /**
  43  * G_CLOSURE_N_NOTIFIERS:
  44  * @cl: a #GClosure
  45  *
  46  * Get the total number of notifiers connected with the closure @cl.
  47  * The count includes the meta marshaller, the finalize and invalidate notifiers
  48  * and the marshal guards. Note that each guard counts as two notifiers.
  49  * See g_closure_set_meta_marshal(), g_closure_add_finalize_notifier(),
  50  * g_closure_add_invalidate_notifier() and g_closure_add_marshal_guards().
  51  *
  52  * Returns: number of notifiers
  53  */
  54 #define G_CLOSURE_N_NOTIFIERS(cl)        ((cl)->meta_marshal + ((cl)->n_guards << 1L) + \
  55                                           (cl)->n_fnotifiers + (cl)->n_inotifiers)
  56 /**
  57  * G_CCLOSURE_SWAP_DATA:
  58  * @cclosure: a #GCClosure
  59  *
  60  * Checks whether the user data of the #GCClosure should be passed as the
  61  * first parameter to the callback. See g_cclosure_new_swap().
  62  *
  63  * Returns: %TRUE if data has to be swapped.
  64  */
  65 #define G_CCLOSURE_SWAP_DATA(cclosure)   (((GClosure*) (cclosure))->derivative_flag)
  66 /**
  67  * G_CALLBACK:
  68  * @f: a function pointer.
  69  *
  70  * Cast a function pointer to a #GCallback.
  71  */
  72 #define G_CALLBACK(f)                    ((GCallback) (f))
  73
  74
  75 /* -- typedefs --- */
  76 typedef struct _GClosure                 GClosure;
  77 typedef struct _GClosureNotifyData       GClosureNotifyData;
  78
  79 /**
  80  * GCallback:
  81  *
  82  * The type used for callback functions in structure definitions and function
  83  * signatures. This doesn't mean that all callback functions must take no
  84  * parameters and return void. The required signature of a callback function
  85  * is determined by the context in which is used (e.g. the signal to which it
  86  * is connected). Use G_CALLBACK() to cast the callback function to a #GCallback.
  87  */
  88 typedef void  (*GCallback)              (void);
  89 /**
  90  * GClosureNotify:
  91  * @data: data specified when registering the notification callback
  92  * @closure: the #GClosure on which the notification is emitted
  93  *
  94  * The type used for the various notification callbacks which can be registered
  95  * on closures.
  96  */
  97 typedef void  (*GClosureNotify)         (gpointer        data,
  98                                          GClosure       *closure);
  99 /**
 100  * GClosureMarshal:
 101  * @closure: the #GClosure to which the marshaller belongs
 102  * @return_value: a #GValue to store the return value. May be %NULL if the
 103  *  callback of @closure doesn't return a value.
 104  * @n_param_values: the length of the @param_values array
 105  * @param_values: an array of #GValue<!-- -->s holding the arguments on
 106  *  which to invoke the callback of @closure
 107  * @invocation_hint: the invocation hint given as the last argument
 108  *  to g_closure_invoke()
 109  * @marshal_data: additional data specified when registering the marshaller,
 110  *  see g_closure_set_marshal() and g_closure_set_meta_marshal()
 111  *
 112  * The type used for marshaller functions.
 113  */
 114 typedef void  (*GClosureMarshal)        (GClosure       *closure,
 115                                          GValue         *return_value,
 116                                          guint           n_param_values,
 117                                          const GValue   *param_values,
 118                                          gpointer        invocation_hint,
 119                                          gpointer        marshal_data);
 120 /**
 121  * GCClosure:
 122  * @closure: the #GClosure
 123  * @callback: the callback function
 124  *
 125  * A #GCClosure is a specialization of #GClosure for C function callbacks.
 126  */
 127 typedef struct _GCClosure                GCClosure;
 128
 129
 130 /* --- structures --- */
 131 struct _GClosureNotifyData
 132 {
 133   gpointer       data;
 134   GClosureNotify notify;
 135 };
 136 /**
 137  * GClosure:
 138  * @in_marshal: Indicates whether the closure is currently being invoked with
 139  *  g_closure_invoke()
 140  * @is_invalid: Indicates whether the closure has been invalidated by
 141  *  g_closure_invalidate()
 142  *
 143  * A #GClosure represents a callback supplied by the programmer.
 144  */
 145 struct _GClosure
 146 {
 147   /*< private >*/
 148   volatile              guint    ref_count : 15;
 149   volatile              guint    meta_marshal : 1;
 150   volatile              guint    n_guards : 1;
 151   volatile              guint    n_fnotifiers : 2;      /* finalization notifiers */
 152   volatile              guint    n_inotifiers : 8;      /* invalidation notifiers */
 153   volatile              guint    in_inotify : 1;
 154   volatile              guint    floating : 1;
 155   /*< protected >*/
 156   volatile              guint    derivative_flag : 1;
 157   /*< public >*/
 158   volatile              guint    in_marshal : 1;
 159   volatile              guint    is_invalid : 1;
 160
 161   /*< private >*/       void   (*marshal)  (GClosure       *closure,
 162                                             GValue /*out*/ *return_value,
 163                                             guint           n_param_values,
 164                                             const GValue   *param_values,
 165                                             gpointer        invocation_hint,
 166                                             gpointer        marshal_data);
 167   /*< protected >*/     gpointer data;
 168
 169   /*< private >*/       GClosureNotifyData *notifiers;
 170
 171   /* invariants/constrains:
 172    * - ->marshal and ->data are _invalid_ as soon as ->is_invalid==TRUE
 173    * - invocation of all inotifiers occours prior to fnotifiers
 174    * - order of inotifiers is random
 175    *   inotifiers may _not_ free/invalidate parameter values (e.g. ->data)
 176    * - order of fnotifiers is random
 177    * - each notifier may only be removed before or during its invocation
 178    * - reference counting may only happen prior to fnotify invocation
 179    *   (in that sense, fnotifiers are really finalization handlers)
 180    */
 181 };
 182 /* closure for C function calls, callback() is the user function
 183  */
 184 struct _GCClosure
 185 {
 186   GClosure      closure;
 187   gpointer      callback;
 188 };
 189
 190
 191 /* --- prototypes --- */
 192 GClosure* g_cclosure_new                        (GCallback      callback_func,
 193                                                  gpointer       user_data,
 194                                                  GClosureNotify destroy_data);
 195 GClosure* g_cclosure_new_swap                   (GCallback      callback_func,
 196                                                  gpointer       user_data,
 197                                                  GClosureNotify destroy_data);
 198 GClosure* g_signal_type_cclosure_new            (GType          itype,
 199                                                  guint          struct_offset);
 200
 201
 202 /* --- prototypes --- */
 203 GClosure* g_closure_ref                         (GClosure       *closure);
 204 void      g_closure_sink                        (GClosure       *closure);
 205 void      g_closure_unref                       (GClosure       *closure);
 206 /* intimidating */
 207 GClosure* g_closure_new_simple                  (guint           sizeof_closure,
 208                                                  gpointer        data);
 209 void      g_closure_add_finalize_notifier       (GClosure       *closure,
 210                                                  gpointer        notify_data,
 211                                                  GClosureNotify  notify_func);
 212 void      g_closure_remove_finalize_notifier    (GClosure       *closure,
 213                                                  gpointer        notify_data,
 214                                                  GClosureNotify  notify_func);
 215 void      g_closure_add_invalidate_notifier     (GClosure       *closure,
 216                                                  gpointer        notify_data,
 217                                                  GClosureNotify  notify_func);
 218 void      g_closure_remove_invalidate_notifier  (GClosure       *closure,
 219                                                  gpointer        notify_data,
 220                                                  GClosureNotify  notify_func);
 221 void      g_closure_add_marshal_guards          (GClosure       *closure,
 222                                                  gpointer        pre_marshal_data,
 223                                                  GClosureNotify  pre_marshal_notify,
 224                                                  gpointer        post_marshal_data,
 225                                                  GClosureNotify  post_marshal_notify);
 226 void      g_closure_set_marshal                 (GClosure       *closure,
 227                                                  GClosureMarshal marshal);
 228 void      g_closure_set_meta_marshal            (GClosure       *closure,
 229                                                  gpointer        marshal_data,
 230                                                  GClosureMarshal meta_marshal);
 231 void      g_closure_invalidate                  (GClosure       *closure);
 232 void      g_closure_invoke                      (GClosure       *closure,
 233                                                  GValue /*out*/ *return_value,
 234                                                  guint           n_param_values,
 235                                                  const GValue   *param_values,
 236                                                  gpointer        invocation_hint);
 237
 238 /* FIXME:
 239    OK:  data_object::destroy            -> closure_invalidate();
 240    MIS: closure_invalidate()            -> disconnect(closure);
 241    MIS: disconnect(closure)             -> (unlink) closure_unref();
 242    OK:  closure_finalize()              -> g_free (data_string);
 243
 244    random remarks:
 245    - need marshaller repo with decent aliasing to base types
 246    - provide marshaller collection, virtually covering anything out there
 247 */
 248
 249 G_END_DECLS
 250
 251 #endif /* __G_CLOSURE_H__ */