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Edit File: gsignal.h

/* GObject - GLib Type, Object, Parameter and Signal Library * Copyright (C) 2000-2001 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General * Public License along with this library; if not, see <http://www.gnu.org/licenses/>. */ #ifndef __G_SIGNAL_H__ #define __G_SIGNAL_H__ #if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION) #error "Only <glib-object.h> can be included directly." #endif #include <gobject/gclosure.h> #include <gobject/gvalue.h> #include <gobject/gparam.h> #include <gobject/gmarshal.h> G_BEGIN_DECLS /* --- typedefs --- */ typedef struct _GSignalQuery GSignalQuery; typedef struct _GSignalInvocationHint GSignalInvocationHint; /** * GSignalCMarshaller: * * This is the signature of marshaller functions, required to marshall * arrays of parameter values to signal emissions into C language callback * invocations. It is merely an alias to #GClosureMarshal since the #GClosure * mechanism takes over responsibility of actual function invocation for the * signal system. */ typedef GClosureMarshal GSignalCMarshaller; /** * GSignalCVaMarshaller: * * This is the signature of va_list marshaller functions, an optional * marshaller that can be used in some situations to avoid * marshalling the signal argument into GValues. */ typedef GVaClosureMarshal GSignalCVaMarshaller; /** * GSignalEmissionHook: * @ihint: Signal invocation hint, see #GSignalInvocationHint. * @n_param_values: the number of parameters to the function, including * the instance on which the signal was emitted. * @param_values: (array length=n_param_values): the instance on which * the signal was emitted, followed by the parameters of the emission. * @data: user data associated with the hook. * * A simple function pointer to get invoked when the signal is emitted. This * allows you to tie a hook to the signal type, so that it will trap all * emissions of that signal, from any object. * * You may not attach these to signals created with the #G_SIGNAL_NO_HOOKS flag. * * Returns: whether it wants to stay connected. If it returns %FALSE, the signal * hook is disconnected (and destroyed). */ typedef gboolean (*GSignalEmissionHook) (GSignalInvocationHint *ihint, guint n_param_values, const GValue *param_values, gpointer data); /** * GSignalAccumulator: * @ihint: Signal invocation hint, see #GSignalInvocationHint. * @return_accu: Accumulator to collect callback return values in, this * is the return value of the current signal emission. * @handler_return: A #GValue holding the return value of the signal handler. * @data: Callback data that was specified when creating the signal. * * The signal accumulator is a special callback function that can be used * to collect return values of the various callbacks that are called * during a signal emission. The signal accumulator is specified at signal * creation time, if it is left %NULL, no accumulation of callback return * values is performed. The return value of signal emissions is then the * value returned by the last callback. * * Returns: The accumulator function returns whether the signal emission * should be aborted. Returning %FALSE means to abort the * current emission and %TRUE is returned for continuation. */ typedef gboolean (*GSignalAccumulator) (GSignalInvocationHint *ihint, GValue *return_accu, const GValue *handler_return, gpointer data); /* --- run, match and connect types --- */ /** * GSignalFlags: * @G_SIGNAL_RUN_FIRST: Invoke the object method handler in the first emission stage. * @G_SIGNAL_RUN_LAST: Invoke the object method handler in the third emission stage. * @G_SIGNAL_RUN_CLEANUP: Invoke the object method handler in the last emission stage. * @G_SIGNAL_NO_RECURSE: Signals being emitted for an object while currently being in * emission for this very object will not be emitted recursively, * but instead cause the first emission to be restarted. * @G_SIGNAL_DETAILED: This signal supports "::detail" appendices to the signal name * upon handler connections and emissions. * @G_SIGNAL_ACTION: Action signals are signals that may freely be emitted on alive * objects from user code via g_signal_emit() and friends, without * the need of being embedded into extra code that performs pre or * post emission adjustments on the object. They can also be thought * of as object methods which can be called generically by * third-party code. * @G_SIGNAL_NO_HOOKS: No emissions hooks are supported for this signal. * @G_SIGNAL_MUST_COLLECT: Varargs signal emission will always collect the * arguments, even if there are no signal handlers connected. Since 2.30. * @G_SIGNAL_DEPRECATED: The signal is deprecated and will be removed * in a future version. A warning will be generated if it is connected while * running with G_ENABLE_DIAGNOSTIC=1. Since 2.32. * @G_SIGNAL_ACCUMULATOR_FIRST_RUN: Only used in #GSignalAccumulator accumulator * functions for the #GSignalInvocationHint::run_type field to mark the first * call to the accumulator function for a signal emission. Since 2.68. * * The signal flags are used to specify a signal's behaviour, the overall * signal description outlines how especially the RUN flags control the * stages of a signal emission. */ typedef enum { G_SIGNAL_RUN_FIRST = 1 << 0, G_SIGNAL_RUN_LAST = 1 << 1, G_SIGNAL_RUN_CLEANUP = 1 << 2, G_SIGNAL_NO_RECURSE = 1 << 3, G_SIGNAL_DETAILED = 1 << 4, G_SIGNAL_ACTION = 1 << 5, G_SIGNAL_NO_HOOKS = 1 << 6, G_SIGNAL_MUST_COLLECT = 1 << 7, G_SIGNAL_DEPRECATED = 1 << 8, /* normal signal flags until 1 << 16 */ G_SIGNAL_ACCUMULATOR_FIRST_RUN = 1 << 17, } GSignalFlags; /** * G_SIGNAL_FLAGS_MASK: * * A mask for all #GSignalFlags bits. */ #define G_SIGNAL_FLAGS_MASK 0x1ff /** * GConnectFlags: * @G_CONNECT_AFTER: whether the handler should be called before or after the * default handler of the signal. * @G_CONNECT_SWAPPED: whether the instance and data should be swapped when * calling the handler; see g_signal_connect_swapped() for an example. * * The connection flags are used to specify the behaviour of a signal's * connection. */ typedef enum { G_CONNECT_AFTER = 1 << 0, G_CONNECT_SWAPPED = 1 << 1 } GConnectFlags; /** * GSignalMatchType: * @G_SIGNAL_MATCH_ID: The signal id must be equal. * @G_SIGNAL_MATCH_DETAIL: The signal detail must be equal. * @G_SIGNAL_MATCH_CLOSURE: The closure must be the same. * @G_SIGNAL_MATCH_FUNC: The C closure callback must be the same. * @G_SIGNAL_MATCH_DATA: The closure data must be the same. * @G_SIGNAL_MATCH_UNBLOCKED: Only unblocked signals may be matched. * * The match types specify what g_signal_handlers_block_matched(), * g_signal_handlers_unblock_matched() and g_signal_handlers_disconnect_matched() * match signals by. */ typedef enum { G_SIGNAL_MATCH_ID = 1 << 0, G_SIGNAL_MATCH_DETAIL = 1 << 1, G_SIGNAL_MATCH_CLOSURE = 1 << 2, G_SIGNAL_MATCH_FUNC = 1 << 3, G_SIGNAL_MATCH_DATA = 1 << 4, G_SIGNAL_MATCH_UNBLOCKED = 1 << 5 } GSignalMatchType; /** * G_SIGNAL_MATCH_MASK: * * A mask for all #GSignalMatchType bits. */ #define G_SIGNAL_MATCH_MASK 0x3f /** * G_SIGNAL_TYPE_STATIC_SCOPE: * * This macro flags signal argument types for which the signal system may * assume that instances thereof remain persistent across all signal emissions * they are used in. This is only useful for non ref-counted, value-copy types. * * To flag a signal argument in this way, add `| G_SIGNAL_TYPE_STATIC_SCOPE` * to the corresponding argument of g_signal_new(). * |[ * g_signal_new ("size_request", * G_TYPE_FROM_CLASS (gobject_class), * G_SIGNAL_RUN_FIRST, * G_STRUCT_OFFSET (GtkWidgetClass, size_request), * NULL, NULL, * _gtk_marshal_VOID__BOXED, * G_TYPE_NONE, 1, * GTK_TYPE_REQUISITION | G_SIGNAL_TYPE_STATIC_SCOPE); * ]| */ #define G_SIGNAL_TYPE_STATIC_SCOPE (G_TYPE_FLAG_RESERVED_ID_BIT) /* --- signal information --- */ /** * GSignalInvocationHint: * @signal_id: The signal id of the signal invoking the callback * @detail: The detail passed on for this emission * @run_type: The stage the signal emission is currently in, this * field will contain one of %G_SIGNAL_RUN_FIRST, * %G_SIGNAL_RUN_LAST or %G_SIGNAL_RUN_CLEANUP and %G_SIGNAL_ACCUMULATOR_FIRST_RUN. * %G_SIGNAL_ACCUMULATOR_FIRST_RUN is only set for the first run of the accumulator * function for a signal emission. * * The #GSignalInvocationHint structure is used to pass on additional information * to callbacks during a signal emission. */ struct _GSignalInvocationHint { guint signal_id; GQuark detail; GSignalFlags run_type; }; /** * GSignalQuery: * @signal_id: The signal id of the signal being queried, or 0 if the * signal to be queried was unknown. * @signal_name: The signal name. * @itype: The interface/instance type that this signal can be emitted for. * @signal_flags: The signal flags as passed in to g_signal_new(). * @return_type: The return type for user callbacks. * @n_params: The number of parameters that user callbacks take. * @param_types: (array length=n_params): The individual parameter types for * user callbacks, note that the effective callback signature is: * |[<!-- language="C" --> * @return_type callback (#gpointer data1, * [param_types param_names,] * gpointer data2); * ]| * * A structure holding in-depth information for a specific signal. It is * filled in by the g_signal_query() function. */ struct _GSignalQuery { guint signal_id; const gchar *signal_name; GType itype; GSignalFlags signal_flags; GType return_type; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */ guint n_params; const GType *param_types; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */ }; /* --- signals --- */ GLIB_AVAILABLE_IN_ALL guint g_signal_newv (const gchar *signal_name, GType itype, GSignalFlags signal_flags, GClosure *class_closure, GSignalAccumulator accumulator, gpointer accu_data, GSignalCMarshaller c_marshaller, GType return_type, guint n_params, GType *param_types); GLIB_AVAILABLE_IN_ALL guint g_signal_new_valist (const gchar *signal_name, GType itype, GSignalFlags signal_flags, GClosure *class_closure, GSignalAccumulator accumulator, gpointer accu_data, GSignalCMarshaller c_marshaller, GType return_type, guint n_params, va_list args); GLIB_AVAILABLE_IN_ALL guint g_signal_new (const gchar *signal_name, GType itype, GSignalFlags signal_flags, guint class_offset, GSignalAccumulator accumulator, gpointer accu_data, GSignalCMarshaller c_marshaller, GType return_type, guint n_params, ...); GLIB_AVAILABLE_IN_ALL guint g_signal_new_class_handler (const gchar *signal_name, GType itype, GSignalFlags signal_flags, GCallback class_handler, GSignalAccumulator accumulator, gpointer accu_data, GSignalCMarshaller c_marshaller, GType return_type, guint n_params, ...); GLIB_AVAILABLE_IN_ALL void g_signal_set_va_marshaller (guint signal_id, GType instance_type, GSignalCVaMarshaller va_marshaller); GLIB_AVAILABLE_IN_ALL void g_signal_emitv (const GValue *instance_and_params, guint signal_id, GQuark detail, GValue *return_value); GLIB_AVAILABLE_IN_ALL void g_signal_emit_valist (gpointer instance, guint signal_id, GQuark detail, va_list var_args); GLIB_AVAILABLE_IN_ALL void g_signal_emit (gpointer instance, guint signal_id, GQuark detail, ...); GLIB_AVAILABLE_IN_ALL void g_signal_emit_by_name (gpointer instance, const gchar *detailed_signal, ...); GLIB_AVAILABLE_IN_ALL guint g_signal_lookup (const gchar *name, GType itype); GLIB_AVAILABLE_IN_ALL const gchar * g_signal_name (guint signal_id); GLIB_AVAILABLE_IN_ALL void g_signal_query (guint signal_id, GSignalQuery *query); GLIB_AVAILABLE_IN_ALL guint* g_signal_list_ids (GType itype, guint *n_ids); GLIB_AVAILABLE_IN_2_66 gboolean g_signal_is_valid_name (const gchar *name); GLIB_AVAILABLE_IN_ALL gboolean g_signal_parse_name (const gchar *detailed_signal, GType itype, guint *signal_id_p, GQuark *detail_p, gboolean force_detail_quark); GLIB_AVAILABLE_IN_ALL GSignalInvocationHint* g_signal_get_invocation_hint (gpointer instance); /* --- signal emissions --- */ GLIB_AVAILABLE_IN_ALL void g_signal_stop_emission (gpointer instance, guint signal_id, GQuark detail); GLIB_AVAILABLE_IN_ALL void g_signal_stop_emission_by_name (gpointer instance, const gchar *detailed_signal); GLIB_AVAILABLE_IN_ALL gulong g_signal_add_emission_hook (guint signal_id, GQuark detail, GSignalEmissionHook hook_func, gpointer hook_data, GDestroyNotify data_destroy); GLIB_AVAILABLE_IN_ALL void g_signal_remove_emission_hook (guint signal_id, gulong hook_id); /* --- signal handlers --- */ GLIB_AVAILABLE_IN_ALL gboolean g_signal_has_handler_pending (gpointer instance, guint signal_id, GQuark detail, gboolean may_be_blocked); GLIB_AVAILABLE_IN_ALL gulong g_signal_connect_closure_by_id (gpointer instance, guint signal_id, GQuark detail, GClosure *closure, gboolean after); GLIB_AVAILABLE_IN_ALL gulong g_signal_connect_closure (gpointer instance, const gchar *detailed_signal, GClosure *closure, gboolean after); GLIB_AVAILABLE_IN_ALL gulong g_signal_connect_data (gpointer instance, const gchar *detailed_signal, GCallback c_handler, gpointer data, GClosureNotify destroy_data, GConnectFlags connect_flags); GLIB_AVAILABLE_IN_ALL void g_signal_handler_block (gpointer instance, gulong handler_id); GLIB_AVAILABLE_IN_ALL void g_signal_handler_unblock (gpointer instance, gulong handler_id); GLIB_AVAILABLE_IN_ALL void g_signal_handler_disconnect (gpointer instance, gulong handler_id); GLIB_AVAILABLE_IN_ALL gboolean g_signal_handler_is_connected (gpointer instance, gulong handler_id); GLIB_AVAILABLE_IN_ALL gulong g_signal_handler_find (gpointer instance, GSignalMatchType mask, guint signal_id, GQuark detail, GClosure *closure, gpointer func, gpointer data); GLIB_AVAILABLE_IN_ALL guint g_signal_handlers_block_matched (gpointer instance, GSignalMatchType mask, guint signal_id, GQuark detail, GClosure *closure, gpointer func, gpointer data); GLIB_AVAILABLE_IN_ALL guint g_signal_handlers_unblock_matched (gpointer instance, GSignalMatchType mask, guint signal_id, GQuark detail, GClosure *closure, gpointer func, gpointer data); GLIB_AVAILABLE_IN_ALL guint g_signal_handlers_disconnect_matched (gpointer instance, GSignalMatchType mask, guint signal_id, GQuark detail, GClosure *closure, gpointer func, gpointer data); GLIB_AVAILABLE_IN_2_62 void g_clear_signal_handler (gulong *handler_id_ptr, gpointer instance); #define g_clear_signal_handler(handler_id_ptr, instance) \ G_STMT_START { \ gpointer const _instance = (instance); \ gulong *const _handler_id_ptr = (handler_id_ptr); \ const gulong _handler_id = *_handler_id_ptr; \ \ if (_handler_id > 0) \ { \ *_handler_id_ptr = 0; \ g_signal_handler_disconnect (_instance, _handler_id); \ } \ } G_STMT_END \ GLIB_AVAILABLE_MACRO_IN_2_62 /* --- overriding and chaining --- */ GLIB_AVAILABLE_IN_ALL void g_signal_override_class_closure (guint signal_id, GType instance_type, GClosure *class_closure); GLIB_AVAILABLE_IN_ALL void g_signal_override_class_handler (const gchar *signal_name, GType instance_type, GCallback class_handler); GLIB_AVAILABLE_IN_ALL void g_signal_chain_from_overridden (const GValue *instance_and_params, GValue *return_value); GLIB_AVAILABLE_IN_ALL void g_signal_chain_from_overridden_handler (gpointer instance, ...); /* --- convenience --- */ /** * g_signal_connect: * @instance: the instance to connect to. * @detailed_signal: a string of the form "signal-name::detail". * @c_handler: the #GCallback to connect. * @data: data to pass to @c_handler calls. * * Connects a #GCallback function to a signal for a particular object. * * The handler will be called before the default handler of the signal. * * See [memory management of signal handlers][signal-memory-management] for * details on how to handle the return value and memory management of @data. * * Returns: the handler ID, of type #gulong (always greater than 0 for successful connections) */ #define g_signal_connect(instance, detailed_signal, c_handler, data) \ g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0) /** * g_signal_connect_after: * @instance: the instance to connect to. * @detailed_signal: a string of the form "signal-name::detail". * @c_handler: the #GCallback to connect. * @data: data to pass to @c_handler calls. * * Connects a #GCallback function to a signal for a particular object. * * The handler will be called after the default handler of the signal. * * Returns: the handler ID, of type #gulong (always greater than 0 for successful connections) */ #define g_signal_connect_after(instance, detailed_signal, c_handler, data) \ g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, G_CONNECT_AFTER) /** * g_signal_connect_swapped: * @instance: the instance to connect to. * @detailed_signal: a string of the form "signal-name::detail". * @c_handler: the #GCallback to connect. * @data: data to pass to @c_handler calls. * * Connects a #GCallback function to a signal for a particular object. * * The instance on which the signal is emitted and @data will be swapped when * calling the handler. This is useful when calling pre-existing functions to * operate purely on the @data, rather than the @instance: swapping the * parameters avoids the need to write a wrapper function. * * For example, this allows the shorter code: * |[<!-- language="C" --> * g_signal_connect_swapped (button, "clicked", * (GCallback) gtk_widget_hide, other_widget); * ]| * * Rather than the cumbersome: * |[<!-- language="C" --> * static void * button_clicked_cb (GtkButton *button, GtkWidget *other_widget) * { * gtk_widget_hide (other_widget); * } * * ... * * g_signal_connect (button, "clicked", * (GCallback) button_clicked_cb, other_widget); * ]| * * Returns: the handler ID, of type #gulong (always greater than 0 for successful connections) */ #define g_signal_connect_swapped(instance, detailed_signal, c_handler, data) \ g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, G_CONNECT_SWAPPED) /** * g_signal_handlers_disconnect_by_func: * @instance: The instance to remove handlers from. * @func: The C closure callback of the handlers (useless for non-C closures). * @data: The closure data of the handlers' closures. * * Disconnects all handlers on an instance that match @func and @data. * * Returns: The number of handlers that matched. */ #define g_signal_handlers_disconnect_by_func(instance, func, data) \ g_signal_handlers_disconnect_matched ((instance), \ (GSignalMatchType) (G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA), \ 0, 0, NULL, (func), (data)) /** * g_signal_handlers_disconnect_by_data: * @instance: The instance to remove handlers from * @data: the closure data of the handlers' closures * * Disconnects all handlers on an instance that match @data. * * Returns: The number of handlers that matched. * * Since: 2.32 */ #define g_signal_handlers_disconnect_by_data(instance, data) \ g_signal_handlers_disconnect_matched ((instance), G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, (data)) /** * g_signal_handlers_block_by_func: * @instance: The instance to block handlers from. * @func: The C closure callback of the handlers (useless for non-C closures). * @data: The closure data of the handlers' closures. * * Blocks all handlers on an instance that match @func and @data. * * Returns: The number of handlers that matched. */ #define g_signal_handlers_block_by_func(instance, func, data) \ g_signal_handlers_block_matched ((instance), \ (GSignalMatchType) (G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA), \ 0, 0, NULL, (func), (data)) /** * g_signal_handlers_unblock_by_func: * @instance: The instance to unblock handlers from. * @func: The C closure callback of the handlers (useless for non-C closures). * @data: The closure data of the handlers' closures. * * Unblocks all handlers on an instance that match @func and @data. * * Returns: The number of handlers that matched. */ #define g_signal_handlers_unblock_by_func(instance, func, data) \ g_signal_handlers_unblock_matched ((instance), \ (GSignalMatchType) (G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA), \ 0, 0, NULL, (func), (data)) GLIB_AVAILABLE_IN_ALL gboolean g_signal_accumulator_true_handled (GSignalInvocationHint *ihint, GValue *return_accu, const GValue *handler_return, gpointer dummy); GLIB_AVAILABLE_IN_ALL gboolean g_signal_accumulator_first_wins (GSignalInvocationHint *ihint, GValue *return_accu, const GValue *handler_return, gpointer dummy); /*< private >*/ GLIB_AVAILABLE_IN_ALL void g_signal_handlers_destroy (gpointer instance); void _g_signals_destroy (GType itype); G_END_DECLS #endif /* __G_SIGNAL_H__ */