gobject/gsignal.h

   1 /* GObject - GLib Type, Object, Parameter and Signal Library
   2  * Copyright (C) 2000-2001 Red Hat, Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General
  15  * Public License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19 #if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
  20 #error "Only <glib-object.h> can be included directly."
  21 #endif
  22
  23 #ifndef __G_SIGNAL_H__
  24 #define __G_SIGNAL_H__
  25
  26 #include        <gobject/gclosure.h>
  27 #include        <gobject/gvalue.h>
  28 #include        <gobject/gparam.h>
  29 #include        <gobject/gmarshal.h>
  30
  31 G_BEGIN_DECLS
  32
  33 /* --- typedefs --- */
  34 typedef struct _GSignalQuery             GSignalQuery;
  35 typedef struct _GSignalInvocationHint    GSignalInvocationHint;
  36 /**
  37  * GSignalCMarshaller:
  38  *
  39  * This is the signature of marshaller functions, required to marshall
  40  * arrays of parameter values to signal emissions into C language callback
  41  * invocations. It is merely an alias to #GClosureMarshal since the #GClosure
  42  * mechanism takes over responsibility of actual function invocation for the
  43  * signal system.
  44  */
  45 typedef GClosureMarshal                  GSignalCMarshaller;
  46 /**
  47  * GSignalEmissionHook:
  48  * @ihint: Signal invocation hint, see #GSignalInvocationHint.
  49  * @n_param_values: the number of parameters to the function, including
  50  *  the instance on which the signal was emitted.
  51  * @param_values: (array length=n_param_values): the instance on which
  52  *  the signal was emitted, followed by the parameters of the emission.
  53  * @data: user data associated with the hook.
  54  *
  55  * A simple function pointer to get invoked when the signal is emitted. This
  56  * allows you to tie a hook to the signal type, so that it will trap all
  57  * emissions of that signal, from any object.
  58  *
  59  * You may not attach these to signals created with the #G_SIGNAL_NO_HOOKS flag.
  60  *
  61  * Returns: whether it wants to stay connected. If it returns %FALSE, the signal
  62  *  hook is disconnected (and destroyed).
  63  */
  64 typedef gboolean (*GSignalEmissionHook) (GSignalInvocationHint *ihint,
  65                                          guint                  n_param_values,
  66                                          const GValue          *param_values,
  67                                          gpointer               data);
  68 /**
  69  * GSignalAccumulator:
  70  * @ihint: Signal invocation hint, see #GSignalInvocationHint.
  71  * @return_accu: Accumulator to collect callback return values in, this
  72  *  is the return value of the current signal emission.
  73  * @handler_return: A #GValue holding the return value of the signal handler.
  74  * @data: Callback data that was specified when creating the signal.
  75  *
  76  * The signal accumulator is a special callback function that can be used
  77  * to collect return values of the various callbacks that are called
  78  * during a signal emission. The signal accumulator is specified at signal
  79  * creation time, if it is left %NULL, no accumulation of callback return
  80  * values is performed. The return value of signal emissions is then the
  81  * value returned by the last callback.
  82  *
  83  * Returns: The accumulator function returns whether the signal emission
  84  *  should be aborted. Returning %FALSE means to abort the
  85  *  current emission and %TRUE is returned for continuation.
  86  */
  87 typedef gboolean (*GSignalAccumulator)  (GSignalInvocationHint *ihint,
  88                                          GValue                *return_accu,
  89                                          const GValue          *handler_return,
  90                                          gpointer               data);
  91
  92
  93 /* --- run, match and connect types --- */
  94 /**
  95  * GSignalFlags:
  96  * @G_SIGNAL_RUN_FIRST: Invoke the object method handler in the first emission stage.
  97  * @G_SIGNAL_RUN_LAST: Invoke the object method handler in the third emission stage.
  98  * @G_SIGNAL_RUN_CLEANUP: Invoke the object method handler in the last emission stage.
  99  * @G_SIGNAL_NO_RECURSE: Signals being emitted for an object while currently being in
 100  *  emission for this very object will not be emitted recursively,
 101  *  but instead cause the first emission to be restarted.
 102  * @G_SIGNAL_DETAILED: This signal supports "::detail" appendices to the signal name
 103  *  upon handler connections and emissions.
 104  * @G_SIGNAL_ACTION: Action signals are signals that may freely be emitted on alive
 105  *  objects from user code via g_signal_emit() and friends, without
 106  *  the need of being embedded into extra code that performs pre or
 107  *  post emission adjustments on the object. They can also be thought
 108  *  of as object methods which can be called generically by
 109  *  third-party code.
 110  * @G_SIGNAL_NO_HOOKS: No emissions hooks are supported for this signal.
 111  * @G_SIGNAL_MUST_COLLECT: Varargs signal emission will always collect the
 112  *   arguments, even if there are no signal handlers connected.  Since 2.30.
 113  *
 114  * The signal flags are used to specify a signal's behaviour, the overall
 115  * signal description outlines how especially the RUN flags control the
 116  * stages of a signal emission.
 117  */
 118 typedef enum
 119 {
 120   G_SIGNAL_RUN_FIRST    = 1 << 0,
 121   G_SIGNAL_RUN_LAST     = 1 << 1,
 122   G_SIGNAL_RUN_CLEANUP  = 1 << 2,
 123   G_SIGNAL_NO_RECURSE   = 1 << 3,
 124   G_SIGNAL_DETAILED     = 1 << 4,
 125   G_SIGNAL_ACTION       = 1 << 5,
 126   G_SIGNAL_NO_HOOKS     = 1 << 6,
 127   G_SIGNAL_MUST_COLLECT = 1 << 7
 128 } GSignalFlags;
 129 /**
 130  * G_SIGNAL_FLAGS_MASK:
 131  *
 132  * A mask for all #GSignalFlags bits.
 133  */
 134 #define G_SIGNAL_FLAGS_MASK  0xff
 135 /**
 136  * GConnectFlags:
 137  * @G_CONNECT_AFTER: whether the handler should be called before or after the
 138  *  default handler of the signal.
 139  * @G_CONNECT_SWAPPED: whether the instance and data should be swapped when
 140  *  calling the handler.
 141  *
 142  * The connection flags are used to specify the behaviour of a signal's
 143  * connection.
 144  */
 145 typedef enum
 146 {
 147   G_CONNECT_AFTER       = 1 << 0,
 148   G_CONNECT_SWAPPED     = 1 << 1
 149 } GConnectFlags;
 150 /**
 151  * GSignalMatchType:
 152  * @G_SIGNAL_MATCH_ID: The signal id must be equal.
 153  * @G_SIGNAL_MATCH_DETAIL: The signal detail be equal.
 154  * @G_SIGNAL_MATCH_CLOSURE: The closure must be the same.
 155  * @G_SIGNAL_MATCH_FUNC: The C closure callback must be the same.
 156  * @G_SIGNAL_MATCH_DATA: The closure data must be the same.
 157  * @G_SIGNAL_MATCH_UNBLOCKED: Only unblocked signals may matched.
 158  *
 159  * The match types specify what g_signal_handlers_block_matched(),
 160  * g_signal_handlers_unblock_matched() and g_signal_handlers_disconnect_matched()
 161  * match signals by.
 162  */
 163 typedef enum
 164 {
 165   G_SIGNAL_MATCH_ID        = 1 << 0,
 166   G_SIGNAL_MATCH_DETAIL    = 1 << 1,
 167   G_SIGNAL_MATCH_CLOSURE   = 1 << 2,
 168   G_SIGNAL_MATCH_FUNC      = 1 << 3,
 169   G_SIGNAL_MATCH_DATA      = 1 << 4,
 170   G_SIGNAL_MATCH_UNBLOCKED = 1 << 5
 171 } GSignalMatchType;
 172 /**
 173  * G_SIGNAL_MATCH_MASK:
 174  *
 175  * A mask for all #GSignalMatchType bits.
 176  */
 177 #define G_SIGNAL_MATCH_MASK  0x3f
 178 /**
 179  * G_SIGNAL_TYPE_STATIC_SCOPE:
 180  *
 181  * This macro flags signal argument types for which the signal system may
 182  * assume that instances thereof remain persistent across all signal emissions
 183  * they are used in. This is only useful for non ref-counted, value-copy types.
 184  *
 185  * To flag a signal argument in this way, add
 186  * <literal>| G_SIGNAL_TYPE_STATIC_SCOPE</literal> to the corresponding argument
 187  * of g_signal_new().
 188  * |[
 189  * g_signal_new ("size_request",
 190  *   G_TYPE_FROM_CLASS (gobject_class),
 191  *       G_SIGNAL_RUN_FIRST,
 192  *       G_STRUCT_OFFSET (GtkWidgetClass, size_request),
 193  *       NULL, NULL,
 194  *       _gtk_marshal_VOID__BOXED,
 195  *       G_TYPE_NONE, 1,
 196  *       GTK_TYPE_REQUISITION | G_SIGNAL_TYPE_STATIC_SCOPE);
 197  * ]|
 198  */
 199 #define G_SIGNAL_TYPE_STATIC_SCOPE (G_TYPE_FLAG_RESERVED_ID_BIT)
 200
 201
 202 /* --- signal information --- */
 203 /**
 204  * GSignalInvocationHint:
 205  * @signal_id: The signal id of the signal invoking the callback
 206  * @detail: The detail passed on for this emission
 207  * @run_type: The stage the signal emission is currently in, this
 208  *  field will contain one of %G_SIGNAL_RUN_FIRST,
 209  *  %G_SIGNAL_RUN_LAST or %G_SIGNAL_RUN_CLEANUP.
 210  *
 211  * The #GSignalInvocationHint structure is used to pass on additional information
 212  * to callbacks during a signal emission.
 213  */
 214 struct _GSignalInvocationHint
 215 {
 216   guint         signal_id;
 217   GQuark        detail;
 218   GSignalFlags  run_type;
 219 };
 220 /**
 221  * GSignalQuery:
 222  * @signal_id: The signal id of the signal being queried, or 0 if the
 223  *  signal to be queried was unknown.
 224  * @signal_name: The signal name.
 225  * @itype: The interface/instance type that this signal can be emitted for.
 226  * @signal_flags: The signal flags as passed in to g_signal_new().
 227  * @return_type: The return type for user callbacks.
 228  * @n_params: The number of parameters that user callbacks take.
 229  * @param_types: The individual parameter types for user callbacks, note that the
 230  *  effective callback signature is:
 231  *  <programlisting>
 232  *  @return_type callback (#gpointer     data1,
 233  *  [#param_types param_names,]
 234  *  #gpointer     data2);
 235  *  </programlisting>
 236  *
 237  * A structure holding in-depth information for a specific signal. It is
 238  * filled in by the g_signal_query() function.
 239  */
 240 struct _GSignalQuery
 241 {
 242   guint         signal_id;
 243   const gchar  *signal_name;
 244   GType         itype;
 245   GSignalFlags  signal_flags;
 246   GType         return_type; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */
 247   guint         n_params;
 248   const GType  *param_types; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */
 249 };
 250
 251
 252 /* --- signals --- */
 253 guint                 g_signal_newv         (const gchar        *signal_name,
 254                                              GType               itype,
 255                                              GSignalFlags        signal_flags,
 256                                              GClosure           *class_closure,
 257                                              GSignalAccumulator  accumulator,
 258                                              gpointer            accu_data,
 259                                              GSignalCMarshaller  c_marshaller,
 260                                              GType               return_type,
 261                                              guint               n_params,
 262                                              GType              *param_types);
 263 guint                 g_signal_new_valist   (const gchar        *signal_name,
 264                                              GType               itype,
 265                                              GSignalFlags        signal_flags,
 266                                              GClosure           *class_closure,
 267                                              GSignalAccumulator  accumulator,
 268                                              gpointer            accu_data,
 269                                              GSignalCMarshaller  c_marshaller,
 270                                              GType               return_type,
 271                                              guint               n_params,
 272                                              va_list             args);
 273 guint                 g_signal_new          (const gchar        *signal_name,
 274                                              GType               itype,
 275                                              GSignalFlags        signal_flags,
 276                                              guint               class_offset,
 277                                              GSignalAccumulator  accumulator,
 278                                              gpointer            accu_data,
 279                                              GSignalCMarshaller  c_marshaller,
 280                                              GType               return_type,
 281                                              guint               n_params,
 282                                              ...);
 283 guint            g_signal_new_class_handler (const gchar        *signal_name,
 284                                              GType               itype,
 285                                              GSignalFlags        signal_flags,
 286                                              GCallback           class_handler,
 287                                              GSignalAccumulator  accumulator,
 288                                              gpointer            accu_data,
 289                                              GSignalCMarshaller  c_marshaller,
 290                                              GType               return_type,
 291                                              guint               n_params,
 292                                              ...);
 293
 294 void                  g_signal_emitv        (const GValue       *instance_and_params,
 295                                              guint               signal_id,
 296                                              GQuark              detail,
 297                                              GValue             *return_value);
 298 void                  g_signal_emit_valist  (gpointer            instance,
 299                                              guint               signal_id,
 300                                              GQuark              detail,
 301                                              va_list             var_args);
 302 void                  g_signal_emit         (gpointer            instance,
 303                                              guint               signal_id,
 304                                              GQuark              detail,
 305                                              ...);
 306 void                  g_signal_emit_by_name (gpointer            instance,
 307                                              const gchar        *detailed_signal,
 308                                              ...);
 309 guint                 g_signal_lookup       (const gchar        *name,
 310                                              GType               itype);
 311 const gchar *         g_signal_name         (guint               signal_id);
 312 void                  g_signal_query        (guint               signal_id,
 313                                              GSignalQuery       *query);
 314 guint*                g_signal_list_ids     (GType               itype,
 315                                              guint              *n_ids);
 316 gboolean              g_signal_parse_name   (const gchar        *detailed_signal,
 317                                              GType               itype,
 318                                              guint              *signal_id_p,
 319                                              GQuark             *detail_p,
 320                                              gboolean            force_detail_quark);
 321 GSignalInvocationHint* g_signal_get_invocation_hint (gpointer    instance);
 322
 323
 324 /* --- signal emissions --- */
 325 void    g_signal_stop_emission              (gpointer             instance,
 326                                              guint                signal_id,
 327                                              GQuark               detail);
 328 void    g_signal_stop_emission_by_name      (gpointer             instance,
 329                                              const gchar         *detailed_signal);
 330 gulong  g_signal_add_emission_hook          (guint                signal_id,
 331                                              GQuark               detail,
 332                                              GSignalEmissionHook  hook_func,
 333                                              gpointer             hook_data,
 334                                              GDestroyNotify       data_destroy);
 335 void    g_signal_remove_emission_hook       (guint                signal_id,
 336                                              gulong               hook_id);
 337
 338
 339 /* --- signal handlers --- */
 340 gboolean g_signal_has_handler_pending         (gpointer           instance,
 341                                                guint              signal_id,
 342                                                GQuark             detail,
 343                                                gboolean           may_be_blocked);
 344 gulong   g_signal_connect_closure_by_id       (gpointer           instance,
 345                                                guint              signal_id,
 346                                                GQuark             detail,
 347                                                GClosure          *closure,
 348                                                gboolean           after);
 349 gulong   g_signal_connect_closure             (gpointer           instance,
 350                                                const gchar       *detailed_signal,
 351                                                GClosure          *closure,
 352                                                gboolean           after);
 353 gulong   g_signal_connect_data                (gpointer           instance,
 354                                                const gchar       *detailed_signal,
 355                                                GCallback          c_handler,
 356                                                gpointer           data,
 357                                                GClosureNotify     destroy_data,
 358                                                GConnectFlags      connect_flags);
 359 void     g_signal_handler_block               (gpointer           instance,
 360                                                gulong             handler_id);
 361 void     g_signal_handler_unblock             (gpointer           instance,
 362                                                gulong             handler_id);
 363 void     g_signal_handler_disconnect          (gpointer           instance,
 364                                                gulong             handler_id);
 365 gboolean g_signal_handler_is_connected        (gpointer           instance,
 366                                                gulong             handler_id);
 367 gulong   g_signal_handler_find                (gpointer           instance,
 368                                                GSignalMatchType   mask,
 369                                                guint              signal_id,
 370                                                GQuark             detail,
 371                                                GClosure          *closure,
 372                                                gpointer           func,
 373                                                gpointer           data);
 374 guint    g_signal_handlers_block_matched      (gpointer           instance,
 375                                                GSignalMatchType   mask,
 376                                                guint              signal_id,
 377                                                GQuark             detail,
 378                                                GClosure          *closure,
 379                                                gpointer           func,
 380                                                gpointer           data);
 381 guint    g_signal_handlers_unblock_matched    (gpointer           instance,
 382                                                GSignalMatchType   mask,
 383                                                guint              signal_id,
 384                                                GQuark             detail,
 385                                                GClosure          *closure,
 386                                                gpointer           func,
 387                                                gpointer           data);
 388 guint    g_signal_handlers_disconnect_matched (gpointer           instance,
 389                                                GSignalMatchType   mask,
 390                                                guint              signal_id,
 391                                                GQuark             detail,
 392                                                GClosure          *closure,
 393                                                gpointer           func,
 394                                                gpointer           data);
 395
 396
 397 /* --- overriding and chaining --- */
 398 void    g_signal_override_class_closure       (guint              signal_id,
 399                                                GType              instance_type,
 400                                                GClosure          *class_closure);
 401 void    g_signal_override_class_handler       (const gchar       *signal_name,
 402                                                GType              instance_type,
 403                                                GCallback          class_handler);
 404 void    g_signal_chain_from_overridden        (const GValue      *instance_and_params,
 405                                                GValue            *return_value);
 406 void   g_signal_chain_from_overridden_handler (gpointer           instance,
 407                                                ...);
 408
 409
 410 /* --- convenience --- */
 411 /**
 412  * g_signal_connect:
 413  * @instance: the instance to connect to.
 414  * @detailed_signal: a string of the form "signal-name::detail".
 415  * @c_handler: the #GCallback to connect.
 416  * @data: data to pass to @c_handler calls.
 417  *
 418  * Connects a #GCallback function to a signal for a particular object.
 419  *
 420  * The handler will be called before the default handler of the signal.
 421  *
 422  * Returns: the handler id
 423  */
 424 #define g_signal_connect(instance, detailed_signal, c_handler, data) \
 425     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
 426 /**
 427  * g_signal_connect_after:
 428  * @instance: the instance to connect to.
 429  * @detailed_signal: a string of the form "signal-name::detail".
 430  * @c_handler: the #GCallback to connect.
 431  * @data: data to pass to @c_handler calls.
 432  *
 433  * Connects a #GCallback function to a signal for a particular object.
 434  *
 435  * The handler will be called after the default handler of the signal.
 436  *
 437  * Returns: the handler id
 438  */
 439 #define g_signal_connect_after(instance, detailed_signal, c_handler, data) \
 440     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, G_CONNECT_AFTER)
 441 /**
 442  * g_signal_connect_swapped:
 443  * @instance: the instance to connect to.
 444  * @detailed_signal: a string of the form "signal-name::detail".
 445  * @c_handler: the #GCallback to connect.
 446  * @data: data to pass to @c_handler calls.
 447  *
 448  * Connects a #GCallback function to a signal for a particular object.
 449  *
 450  * The instance on which the signal is emitted and @data will be swapped when
 451  * calling the handler.
 452  *
 453  * Returns: the handler id
 454  */
 455 #define g_signal_connect_swapped(instance, detailed_signal, c_handler, data) \
 456     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, G_CONNECT_SWAPPED)
 457 /**
 458  * g_signal_handlers_disconnect_by_func:
 459  * @instance: The instance to remove handlers from.
 460  * @func: The C closure callback of the handlers (useless for non-C closures).
 461  * @data: The closure data of the handlers' closures.
 462  *
 463  * Disconnects all handlers on an instance that match @func and @data.
 464  *
 465  * Returns: The number of handlers that matched.
 466  */
 467 #define g_signal_handlers_disconnect_by_func(instance, func, data)                                              \
 468     g_signal_handlers_disconnect_matched ((instance),                                                           \
 469                                           (GSignalMatchType) (G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA),       \
 470                                           0, 0, NULL, (func), (data))
 471 /**
 472  * g_signal_handlers_block_by_func:
 473  * @instance: The instance to block handlers from.
 474  * @func: The C closure callback of the handlers (useless for non-C closures).
 475  * @data: The closure data of the handlers' closures.
 476  *
 477  * Blocks all handlers on an instance that match @func and @data.
 478  *
 479  * Returns: The number of handlers that matched.
 480  */
 481 #define g_signal_handlers_block_by_func(instance, func, data)                                                   \
 482     g_signal_handlers_block_matched      ((instance),                                                           \
 483                                           (GSignalMatchType) (G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA),       \
 484                                           0, 0, NULL, (func), (data))
 485 /**
 486  * g_signal_handlers_unblock_by_func:
 487  * @instance: The instance to unblock handlers from.
 488  * @func: The C closure callback of the handlers (useless for non-C closures).
 489  * @data: The closure data of the handlers' closures.
 490  *
 491  * Unblocks all handlers on an instance that match @func and @data.
 492  *
 493  * Returns: The number of handlers that matched.
 494  */
 495 #define g_signal_handlers_unblock_by_func(instance, func, data)                                                 \
 496     g_signal_handlers_unblock_matched    ((instance),                                                           \
 497                                           (GSignalMatchType) (G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA),       \
 498                                           0, 0, NULL, (func), (data))
 499
 500
 501 gboolean g_signal_accumulator_true_handled (GSignalInvocationHint *ihint,
 502                                             GValue                *return_accu,
 503                                             const GValue          *handler_return,
 504                                             gpointer               dummy);
 505
 506 gboolean g_signal_accumulator_first_wins   (GSignalInvocationHint *ihint,
 507                                             GValue                *return_accu,
 508                                             const GValue          *handler_return,
 509                                             gpointer               dummy);
 510
 511 /*< private >*/
 512 void     g_signal_handlers_destroy            (gpointer           instance);
 513 void     _g_signals_destroy                   (GType              itype);
 514
 515 G_END_DECLS
 516
 517 #endif /* __G_SIGNAL_H__ */