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Migrating docs.

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* docs/reference/gobject/tmpl/signals.sgml:
	* gobject/gclosure.c:
	* gobject/gobject.c:
	* gobject/gsignal.c:
	* gobject/gsignal.h:
	  Migrating docs.


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@ -1,3 +1,12 @@
2008-06-22 Stefan Kost <ensonic@users.sf.net>
* docs/reference/gobject/tmpl/signals.sgml:
* gobject/gclosure.c:
* gobject/gobject.c:
* gobject/gsignal.c:
* gobject/gsignal.h:
Migrating docs.
2008-06-22 Stefan Kost <ensonic@users.sf.net>
* docs/reference/gobject/Makefile.am:

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<!-- ##### SECTION Title ##### -->
Signals
<!-- ##### SECTION Short_Description ##### -->
A means for customization of object behaviour and a general purpose notification mechanism
<!-- ##### SECTION Long_Description ##### -->
<para>
The basic concept of the signal system is that of the <emphasis>emission</emphasis>
of a signal.
Signals are introduced per-type and are identified through strings.
Signals introduced for a parent type are available in derived types as well,
so basically they are a per-type facility that is inherited.
A signal emission mainly involves invocation of a certain set of callbacks in
precisely defined manner. There are two main categories of such callbacks,
per-object
<footnote><para>Although signals can deal with any kind of instantiatable type,
i'm referring to those types as "object types" in the following, simply
because that is the context most users will encounter signals in.
</para></footnote>
ones and user provided ones.
The per-object callbacks are most often referred to as "object method
handler" or "default (signal) handler", while user provided callbacks are
usually just called "signal handler".
The object method handler is provided at signal creation time (this most
frequently happens at the end of an object class' creation), while user
provided handlers are frequently connected and disconnected to/from a certain
signal on certain object instances.
</para>
<para>
A signal emission consists of five stages, unless prematurely stopped:
<variablelist>
<varlistentry><term></term><listitem><para>
1 - Invocation of the object method handler for %G_SIGNAL_RUN_FIRST signals
</para></listitem></varlistentry>
<varlistentry><term></term><listitem><para>
2 - Invocation of normal user-provided signal handlers (<emphasis>after</emphasis> flag %FALSE)
</para></listitem></varlistentry>
<varlistentry><term></term><listitem><para>
3 - Invocation of the object method handler for %G_SIGNAL_RUN_LAST signals
</para></listitem></varlistentry>
<varlistentry><term></term><listitem><para>
4 - Invocation of user provided signal handlers, connected with an <emphasis>after</emphasis> flag of %TRUE
</para></listitem></varlistentry>
<varlistentry><term></term><listitem><para>
5 - Invocation of the object method handler for %G_SIGNAL_RUN_CLEANUP signals
</para></listitem></varlistentry>
</variablelist>
The user-provided signal handlers are called in the order they were
connected in.
All handlers may prematurely stop a signal emission, and any number of
handlers may be connected, disconnected, blocked or unblocked during
a signal emission.
There are certain criteria for skipping user handlers in stages 2 and 4
of a signal emission.
First, user handlers may be <emphasis>blocked</emphasis>, blocked handlers are omitted
during callback invocation, to return from the "blocked" state, a
handler has to get unblocked exactly the same amount of times
it has been blocked before.
Second, upon emission of a %G_SIGNAL_DETAILED signal, an additional
"detail" argument passed in to g_signal_emit() has to match the detail
argument of the signal handler currently subject to invocation.
Specification of no detail argument for signal handlers (omission of the
detail part of the signal specification upon connection) serves as a
wildcard and matches any detail argument passed in to emission.
</para>
<!-- ##### SECTION See_Also ##### -->
<para>
</para>
<!-- ##### SECTION Stability_Level ##### -->
<!-- ##### STRUCT GSignalInvocationHint ##### -->
<para>
The #GSignalInvocationHint structure is used to pass on additional information
to callbacks during a signal emission.
</para>
@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.
<!-- ##### USER_FUNCTION GSignalAccumulator ##### -->
<para>
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.
</para>
@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.
@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 GSignalCMarshaller ##### -->
<para>
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.
</para>
<!-- ##### USER_FUNCTION GSignalEmissionHook ##### -->
<para>
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.
</para>
<para>
You may not attach these to signals created with the #G_SIGNAL_NO_HOOKS flag.
</para>
@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: the instance on which the signal was emitted, followed by the
parameters of the emission.
@data: user data associated with the hook.
@Returns: whether it wants to stay connected. If it returns %FALSE, the signal
hook is disconnected (and destroyed).
<!-- ##### ENUM GSignalFlags ##### -->
<para>
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.
</para>
@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.
<!-- ##### ENUM GSignalMatchType ##### -->
<para>
The match types specify what g_signal_handlers_block_matched(),
g_signal_handlers_unblock_matched() and g_signal_handlers_disconnect_matched()
match signals by.
</para>
@G_SIGNAL_MATCH_ID: The signal id must be equal.
@G_SIGNAL_MATCH_DETAIL: The signal detail 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 matched.
<!-- ##### STRUCT GSignalQuery ##### -->
<para>
A structure holding in-depth information for a specific signal. It is
filled in by the g_signal_query() function.
</para>
@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: The individual parameter types for user callbacks, note that the
effective callback signature is:
<programlisting>
@return_type callback (#gpointer data1,
[#param_types param_names,]
#gpointer data2);
</programlisting>
<!-- ##### MACRO G_SIGNAL_TYPE_STATIC_SCOPE ##### -->
<para>
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.
</para>
<para>
To flag a signal argument in this way, add
<literal>| G_SIGNAL_TYPE_STATIC_SCOPE</literal> to the corresponding argument
of g_signal_new().
</para>
<informalexample>
<programlisting>
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);
</programlisting>
</informalexample>
<!-- ##### MACRO G_SIGNAL_MATCH_MASK ##### -->
<para>
A mask for all #GSignalMatchType bits.
</para>
<!-- ##### MACRO G_SIGNAL_FLAGS_MASK ##### -->
<para>
A mask for all #GSignalFlags bits.
</para>
<!-- ##### FUNCTION g_signal_new ##### -->
<para>
Creates a new signal. (This is usually done in the class initializer.)
</para>
<para>
A signal name consists of segments consisting of ASCII letters and
digits, separated by either the '-' or '_' character. The first
character of a signal name must be a letter. Names which violate these
rules lead to undefined behaviour of the GSignal system.
</para>
<para>
When registering a signal and looking up a signal, either separator can
be used, but they cannot be mixed.
</para>
@signal_name: the name for the signal
@itype: the type this signal pertains to. It will also pertain to
types which are derived from this type.
@signal_flags: a combination of #GSignalFlags specifying detail of when
the default handler is to be invoked. You should at least specify
%G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST.
@class_offset: The offset of the function pointer in the class structure
for this type. Used to invoke a class method generically. Pass 0 to
not associate a class method with this signal.
@accumulator: the accumulator for this signal; may be %NULL.
@accu_data: user data for the @accumulator.
@c_marshaller: the function to translate arrays of parameter values to
signal emissions into C language callback invocations.
@return_type: the type of return value, or #G_TYPE_NONE for a signal
without a return value.
@n_params: the number of parameter types to follow.
@Varargs: a list of types, one for each parameter.
@Returns: the signal id
<!-- ##### FUNCTION g_signal_newv ##### -->
<para>
Creates a new signal. (This is usually done in the class initializer.)
</para>
<para>
See g_signal_new() for details on allowed signal names.
</para>
@signal_name: the name for the signal
@itype: the type this signal pertains to. It will also pertain to
types which are derived from this type.
@signal_flags: a combination of #GSignalFlags specifying detail of when
the default handler is to be invoked. You should at least specify
%G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST.
@class_closure: The closure to invoke on signal emission; may be %NULL.
@accumulator: the accumulator for this signal; may be %NULL.
@accu_data: user data for the @accumulator.
@c_marshaller: the function to translate arrays of parameter values to
signal emissions into C language callback invocations.
@return_type: the type of return value, or #G_TYPE_NONE for a signal
without a return value.
@n_params: the length of @param_types.
@param_types: an array types, one for each parameter.
@Returns: the signal id
<!-- ##### FUNCTION g_signal_new_valist ##### -->
<para>
Creates a new signal. (This is usually done in the class initializer.)
</para>
<para>
See g_signal_new() for details on allowed signal names.
</para>
@signal_name: the name for the signal
@itype: the type this signal pertains to. It will also pertain to
types which are derived from this type.
@signal_flags: a combination of #GSignalFlags specifying detail of when
the default handler is to be invoked. You should at least specify
%G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST.
@class_closure: The closure to invoke on signal emission; may be %NULL.
@accumulator: the accumulator for this signal; may be %NULL.
@accu_data: user data for the @accumulator.
@c_marshaller: the function to translate arrays of parameter values to
signal emissions into C language callback invocations.
@return_type: the type of return value, or #G_TYPE_NONE for a signal
without a return value.
@n_params: the number of parameter types in @args.
@args: va_list of #GType, one for each parameter.
@Returns: the signal id
<!-- ##### FUNCTION g_signal_query ##### -->
<para>
Queries the signal system for in-depth information about a
specific signal. This function will fill in a user-provided
structure to hold signal-specific information. If an invalid
signal id is passed in, the @signal_id member of the #GSignalQuery
is 0. All members filled into the #GSignalQuery structure should
be considered constant and have to be left untouched.
</para>
@signal_id: The signal id of the signal to query information for.
@query: A user provided structure that is filled in with constant
values upon success.
<!-- ##### FUNCTION g_signal_lookup ##### -->
<para>
Given the name of the signal and the type of object it connects to, gets
the signal's identifying integer. Emitting the signal by number is
somewhat faster than using the name each time.
</para>
<para>
Also tries the ancestors of the given type.
</para>
<para>
See g_signal_new() for details on allowed signal names.
</para>
@name: the signal's name.
@itype: the type that the signal operates on.
@Returns: the signal's identifying number, or 0 if no signal was found.
<!-- ##### FUNCTION g_signal_name ##### -->
<para>
Given the signal's identifier, finds its name.
</para>
<para>
Two different signals may have the same name, if they have differing types.
</para>
@signal_id: the signal's identifying number.
@Returns: the signal name, or %NULL if the signal number was invalid.
<!-- ##### FUNCTION g_signal_list_ids ##### -->
<para>
Lists the signals by id that a certain instance or interface type
created. Further information about the signals can be acquired through
g_signal_query().
</para>
@itype: Instance or interface type.
@n_ids: Location to store the number of signal ids for @itype.
@Returns: Newly allocated array of signal IDs.
<!-- ##### FUNCTION g_signal_emit ##### -->
<para>
Emits a signal.
</para>
<para>
Note that g_signal_emit() resets the return value to the default
if no handlers are connected, in contrast to g_signal_emitv().
</para>
@instance: the instance the signal is being emitted on.
@signal_id: the signal id
@detail: the detail
@Varargs: parameters to be passed to the signal, followed by a
location for the return value. If the return type of the signal
is #G_TYPE_NONE, the return value location can be omitted.
<!-- ##### FUNCTION g_signal_emit_by_name ##### -->
<para>
Emits a signal.
</para>
<para>
Note that g_signal_emit_by_name() resets the return value to the default
if no handlers are connected, in contrast to g_signal_emitv().
</para>
@instance: the instance the signal is being emitted on.
@detailed_signal: a string of the form "signal-name::detail".
@Varargs: parameters to be passed to the signal, followed by a
location for the return value. If the return type of the signal
is #G_TYPE_NONE, the return value location can be omitted.
<!-- ##### FUNCTION g_signal_emitv ##### -->
<para>
Emits a signal.
</para>
<para>
Note that g_signal_emitv() doesn't change @return_value if no handlers are
connected, in contrast to g_signal_emit() and g_signal_emit_valist().
</para>
@instance_and_params: argument list for the signal emission. The first
element in the array is a #GValue for the instance the signal is
being emitted on. The rest are any arguments to be passed to the
signal.
@signal_id: the signal id
@detail: the detail
@return_value: Location to store the return value of the signal emission.
<!-- ##### FUNCTION g_signal_emit_valist ##### -->
<para>
Emits a signal.
</para>
<para>
Note that g_signal_emit_valist() resets the return value to the default
if no handlers are connected, in contrast to g_signal_emitv().
</para>
@instance: the instance the signal is being emitted on.
@signal_id: the signal id
@detail: the detail
@var_args: a list of parameters to be passed to the signal, followed by a
location for the return value. If the return type of the signal
is #G_TYPE_NONE, the return value location can be omitted.
<!-- ##### MACRO g_signal_connect ##### -->
<para>
Connects a #GCallback function to a signal for a particular object.
</para>
<para>
The handler will be called before the default handler of the signal.
</para>
@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.
@Returns: the handler id
<!-- ##### MACRO g_signal_connect_after ##### -->
<para>
Connects a #GCallback function to a signal for a particular object.
</para>
<para>
The handler will be called after the default handler of the signal.
</para>
@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.
@Returns: the handler id
<!-- ##### MACRO g_signal_connect_swapped ##### -->
<para>
Connects a #GCallback function to a signal for a particular object.
</para>
<para>
The instance on which the signal is emitted and @data will be swapped when
calling the handler.
</para>
@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.
@Returns: the handler id
<!-- ##### FUNCTION g_signal_connect_object ##### -->
<para>
This is similar to g_signal_connect_data(), but uses a closure which
ensures that the @gobject stays alive during the call to @c_handler
by temporarily adding a reference count to @gobject.
</para>
<para>
Note that there is a bug in GObject that makes this function
much less useful than it might seem otherwise. Once @gobject is
disposed, the callback will no longer be called, but, the signal
handler is <emphasis>not</emphasis> currently disconnected. If the
@instance is itself being freed at the same time than this doesn't
matter, since the signal will automatically be removed, but
if @instance persists, then the signal handler will leak. You
should not remove the signal yourself because in a future versions of
GObject, the handler <emphasis>will</emphasis> automatically
be disconnected.
</para>
<para>
It's possible to work around this problem in a way that will
continue to work with future versions of GObject by checking
that the signal handler is still connected before disconnected it:
<informalexample><programlisting>
if (g_signal_handler_is_connected (instance, id))
g_signal_handler_disconnect (instance, id);
</programlisting></informalexample>
</para>
@instance: the instance to connect to.
@detailed_signal: a string of the form "signal-name::detail".
@c_handler: the #GCallback to connect.
@gobject: the object to pass as data to @c_handler.
@connect_flags: a combination of #GConnnectFlags.
@Returns: the handler id.
<!-- ##### ENUM GConnectFlags ##### -->
<para>
The connection flags are used to specify the behaviour of a signal's
connection.
</para>
@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.
<!-- ##### FUNCTION g_signal_connect_data ##### -->
<para>
Connects a #GCallback function to a signal for a particular object. Similar
to g_signal_connect(), but allows to provide a #GClosureNotify for the data
which will be called when the signal handler is disconnected and no longer
used. Specify @connect_flags if you need <literal>..._after()</literal> pr
<literal>..._swapped()</literal> variants of this function.
</para>
@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.
@destroy_data: a #GClosureNotify for @data.
@connect_flags: a combination of #GConnectFlags.
@Returns: the handler id
<!-- ##### FUNCTION g_signal_connect_closure ##### -->
<para>
Connects a closure to a signal for a particular object.
</para>
@instance: the instance to connect to.
@detailed_signal: a string of the form "signal-name::detail".
@closure: the closure to connect.
@after: whether the handler should be called before or after the
default handler of the signal.
@Returns: the handler id
<!-- ##### FUNCTION g_signal_connect_closure_by_id ##### -->
<para>
Connects a closure to a signal for a particular object.
</para>
@instance: the instance to connect to.
@signal_id: the id of the signal.
@detail: the detail.
@closure: the closure to connect.
@after: whether the handler should be called before or after the
default handler of the signal.
@Returns: the handler id
<!-- ##### FUNCTION g_signal_handler_block ##### -->
<para>
Blocks a handler of an instance so it will not be called during
any signal emissions unless it is unblocked again. Thus "blocking"
a signal handler means to temporarily deactive it, a signal handler
has to be unblocked exactly the same amount of times it has been
blocked before to become active again.
</para>
<para>
The @handler_id has to be a valid signal handler id, connected to a
signal of @instance.
</para>
@instance: The instance to block the signal handler of.
@handler_id: Handler id of the handler to be blocked.
<!-- ##### FUNCTION g_signal_handler_unblock ##### -->
<para>
Undoes the effect of a previous g_signal_handler_block() call.
A blocked handler is skipped during signal emissions and will not be
invoked, unblocking it (for exactly the amount of times it has been
blocked before) reverts its "blocked" state, so the handler will be
recognized by the signal system and is called upon future or currently
ongoing signal emissions (since the order in which handlers are
called during signal emissions is deterministic, whether the
unblocked handler in question is called as part of a currently
ongoing emission depends on how far that emission has proceeded
yet).
</para>
<para>
The @handler_id has to be a valid id of a signal handler that is
connected to a signal of @instance and is currently blocked.
</para>
@instance: The instance to unblock the signal handler of.
@handler_id: Handler id of the handler to be unblocked.
<!-- ##### FUNCTION g_signal_handler_disconnect ##### -->
<para>
Disconnects a handler from an instance so it will not be called during
any future or currently ongoing emissions of the signal it has been
connected to. The @handler_id becomes invalid and may be reused.
</para>
<para>
The @handler_id has to be a valid signal handler id, connected to a
signal of @instance.
</para>
@instance: The instance to remove the signal handler from.
@handler_id: Handler id of the handler to be disconnected.
<!-- ##### FUNCTION g_signal_handler_find ##### -->
<para>
Finds the first signal handler that matches certain selection criteria.
The criteria mask is passed as an OR-ed combination of #GSignalMatchType
flags, and the criteria values are passed as arguments.
The match @mask has to be non-0 for successful matches.
If no handler was found, 0 is returned.
</para>
@instance: The instance owning the signal handler to be found.
@mask: Mask indicating which of @signal_id, @detail, @closure, @func
and/or @data the handler has to match.
@signal_id: Signal the handler has to be connected to.
@detail: Signal detail the handler has to be connected to.
@closure: The closure the handler will invoke.
@func: The C closure callback of the handler (useless for non-C closures).
@data: The closure data of the handler's closure.
@Returns: A valid non-0 signal handler id for a successful match.
<!-- ##### FUNCTION g_signal_handlers_block_matched ##### -->
<para>
Blocks all handlers on an instance that match a certain selection criteria.
The criteria mask is passed as an OR-ed combination of #GSignalMatchType
flags, and the criteria values are passed as arguments.
Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
If no handlers were found, 0 is returned, the number of blocked handlers
otherwise.
</para>
@instance: The instance to block handlers from.
@mask: Mask indicating which of @signal_id, @detail, @closure, @func
and/or @data the handlers have to match.
@signal_id: Signal the handlers have to be connected to.
@detail: Signal detail the handlers have to be connected to.
@closure: The closure the handlers will invoke.
@func: The C closure callback of the handlers (useless for non-C closures).
@data: The closure data of the handlers' closures.
@Returns: The number of handlers that matched.
<!-- ##### FUNCTION g_signal_handlers_unblock_matched ##### -->
<para>
Unblocks all handlers on an instance that match a certain selection
criteria. The criteria mask is passed as an OR-ed combination of
#GSignalMatchType flags, and the criteria values are passed as arguments.
Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
If no handlers were found, 0 is returned, the number of unblocked handlers
otherwise. The match criteria should not apply to any handlers that are
not currently blocked.
</para>
@instance: The instance to unblock handlers from.
@mask: Mask indicating which of @signal_id, @detail, @closure, @func
and/or @data the handlers have to match.
@signal_id: Signal the handlers have to be connected to.
@detail: Signal detail the handlers have to be connected to.
@closure: The closure the handlers will invoke.
@func: The C closure callback of the handlers (useless for non-C closures).
@data: The closure data of the handlers' closures.
@Returns: The number of handlers that matched.
<!-- ##### FUNCTION g_signal_handlers_disconnect_matched ##### -->
<para>
Disconnects all handlers on an instance that match a certain selection
criteria. The criteria mask is passed as an OR-ed combination of
#GSignalMatchType flags, and the criteria values are passed as arguments.
Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
If no handlers were found, 0 is returned, the number of disconnected
handlers otherwise.
</para>
@instance: The instance to remove handlers from.
@mask: Mask indicating which of @signal_id, @detail, @closure, @func
and/or @data the handlers have to match.
@signal_id: Signal the handlers have to be connected to.
@detail: Signal detail the handlers have to be connected to.
@closure: The closure the handlers will invoke.
@func: The C closure callback of the handlers (useless for non-C closures).
@data: The closure data of the handlers' closures.
@Returns: The number of handlers that matched.
<!-- ##### FUNCTION g_signal_handler_is_connected ##### -->
<para>
Returns whether @handler_id is the id of a handler connected to @instance.
</para>
@instance: The instance where a signal handler is sought.
@handler_id: the handler id.
@Returns: whether @handler_id identifies a handler connected to @instance.
<!-- ##### MACRO g_signal_handlers_block_by_func ##### -->
<para>
Blocks all handlers on an instance that match @func and @data.
</para>
@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.
@Returns: The number of handlers that matched.
<!-- ##### MACRO g_signal_handlers_unblock_by_func ##### -->
<para>
Unblocks all handlers on an instance that match @func and @data.
</para>
@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.
@Returns: The number of handlers that matched.
<!-- ##### MACRO g_signal_handlers_disconnect_by_func ##### -->
<para>
Disconnects all handlers on an instance that match @func and @data.
</para>
@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.
@Returns: The number of handlers that matched.
<!-- ##### FUNCTION g_signal_has_handler_pending ##### -->
<para>
Returns whether there are any handlers connected to @instance for the
given signal id and detail.
</para>
<para>
One example of when you might use this is when the arguments to the
signal are difficult to compute. A class implementor may opt to not emit
the signal if no one is attached anyway, thus saving the cost of building
the arguments.
</para>
@instance: the object whose signal handlers are sought.
@signal_id: the signal id.
@detail: the detail.
@may_be_blocked: whether blocked handlers should count as match.
@Returns: %TRUE if a handler is connected to the signal,
%FALSE otherwise.
<!-- ##### FUNCTION g_signal_stop_emission ##### -->
<para>
Stops a signal's current emission.
</para>
<para>
This will prevent the default method from running, if the signal was
%G_SIGNAL_RUN_LAST and you connected normally (i.e. without the "after"
flag).
</para>
<para>
Prints a warning if used on a signal which isn't being emitted.
</para>
@instance: the object whose signal handlers you wish to stop.
@signal_id: the signal identifier, as returned by g_signal_lookup().
@detail: the detail which the signal was emitted with.
<!-- ##### FUNCTION g_signal_stop_emission_by_name ##### -->
<para>
Stops a signal's current emission.
</para>
<para>
This is just like g_signal_stop_emission() except it will look up the
signal id for you.
</para>
@instance: the object whose signal handlers you wish to stop.
@detailed_signal: a string of the form "signal-name::detail".
<!-- ##### FUNCTION g_signal_override_class_closure ##### -->
<para>
Overrides the class closure (i.e. the default handler) for the given signal
for emissions on instances of @instance_type. @instance_type must be derived
from the type to which the signal belongs.
</para>
@signal_id: the signal id
@instance_type: the instance type on which to override the class closure
for the signal.
@class_closure: the closure.
<!-- ##### FUNCTION g_signal_chain_from_overridden ##### -->
<para>
Calls the original class closure of a signal. This function should only
be called from an overridden class closure; see
g_signal_override_class_closure().
</para>
@instance_and_params: the argument list of the signal emission. The first
element in the array is a #GValue for the instance the signal is being
emitted on. The rest are any arguments to be passed to the signal.
@return_value: Location for the return value.
<!-- ##### FUNCTION g_signal_add_emission_hook ##### -->
<para>
Adds an emission hook for a signal, which will get called for any emission
of that signal, independent of the instance. This is possible only
for signals which don't have #G_SIGNAL_NO_HOOKS flag set.
</para>
@signal_id: the signal identifier, as returned by g_signal_lookup().
@detail: the detail on which to call the hook.
@hook_func: a #GSignalEmissionHook function.
@hook_data: user data for @hook_func.
@data_destroy: a #GDestroyNotify for @hook_data.
@Returns: the hook id, for later use with g_signal_remove_emission_hook().
<!-- ##### FUNCTION g_signal_remove_emission_hook ##### -->
<para>
Deletes an emission hook.
</para>
@signal_id: the id of the signal
@hook_id: the id of the emission hook, as returned by
g_signal_add_emission_hook()
<!-- ##### FUNCTION g_signal_parse_name ##### -->
<para>
Internal function to parse a signal name into its @signal_id
and @detail quark.
</para>
@detailed_signal: a string of the form "signal-name::detail".
@itype: The interface/instance type that introduced "signal-name".
@signal_id_p: Location to store the signal id.
@detail_p: Location to store the detail quark.
@force_detail_quark: %TRUE forces creation of a #GQuark for the detail.
@Returns: Whether the signal name could successfully be parsed and @signal_id_p and @detail_p contain valid return values.
<!-- ##### FUNCTION g_signal_get_invocation_hint ##### -->
<para>
Returns the invocation hint of the innermost signal emission of instance.
</para>
@instance: the instance to query
@Returns: the invocation hint of the innermost signal emission.
<!-- ##### FUNCTION g_signal_type_cclosure_new ##### -->
<para>
Creates a new closure which invokes the function found at the offset
@struct_offset in the class structure of the interface or classed type
identified by @itype.
</para>
@itype: the #GType identifier of an interface or classed type
@struct_offset: the offset of the member function of @itype's class
structure which is to be invoked by the new closure
@Returns: a new #GCClosure
<!-- ##### FUNCTION g_signal_accumulator_true_handled ##### -->
<para>
A predefined #GSignalAccumulator for signals that return a
boolean values. The behavior that this accumulator gives is
that a return of %TRUE stops the signal emission: no further
callbacks will be invoked, while a return of %FALSE allows
the emission to coninue. The idea here is that a %TRUE return
indicates that the callback <emphasis>handled</emphasis> the signal,
and no further handling is needed.
</para>
@ihint: standard #GSignalAccumulator parameter
@return_accu: standard #GSignalAccumulator parameter
@handler_return: standard #GSignalAccumulator parameter
@dummy: standard #GSignalAccumulator parameter
@Returns: standard #GSignalAccumulator result
@Since: 2.4

12
gobject/gclosure.c
View File

@ -893,6 +893,18 @@ g_type_iface_meta_marshal (GClosure *closure,
callback);
}
/**
* g_signal_type_cclosure_new:
* @itype: the #GType identifier of an interface or classed type
* @struct_offset: the offset of the member function of @itype's class
* structure which is to be invoked by the new closure
*
* Creates a new closure which invokes the function found at the offset
* @struct_offset in the class structure of the interface or classed type
* identified by @itype.
*
* Returns: a new #GCClosure
*/
GClosure*
g_signal_type_cclosure_new (GType itype,
guint struct_offset)

33
gobject/gobject.c
View File

@ -2845,6 +2845,39 @@ g_value_dup_object (const GValue *value)
return value->data[0].v_pointer ? g_object_ref (value->data[0].v_pointer) : NULL;
}
/**
* g_signal_connect_object:
* @instance: the instance to connect to.
* @detailed_signal: a string of the form "signal-name::detail".
* @c_handler: the #GCallback to connect.
* @gobject: the object to pass as data to @c_handler.
* @connect_flags: a combination of #GConnnectFlags.
*
* This is similar to g_signal_connect_data(), but uses a closure which
* ensures that the @gobject stays alive during the call to @c_handler
* by temporarily adding a reference count to @gobject.
*
* Note that there is a bug in GObject that makes this function
* much less useful than it might seem otherwise. Once @gobject is
* disposed, the callback will no longer be called, but, the signal
* handler is <emphasis>not</emphasis> currently disconnected. If the
* @instance is itself being freed at the same time than this doesn't
* matter, since the signal will automatically be removed, but
* if @instance persists, then the signal handler will leak. You
* should not remove the signal yourself because in a future versions of
* GObject, the handler <emphasis>will</emphasis> automatically
* be disconnected.
*
* It's possible to work around this problem in a way that will
* continue to work with future versions of GObject by checking
* that the signal handler is still connected before disconnected it:
* <informalexample><programlisting>
* if (g_signal_handler_is_connected (instance, id))
* g_signal_handler_disconnect (instance, id);
* </programlisting></informalexample>
*
* Returns: the handler id.
*/
gulong
g_signal_connect_object (gpointer instance,
const gchar *detailed_signal,

551
gobject/gsignal.c
View File

@ -19,7 +19,67 @@
* this code is based on the original GtkSignal implementation
* for the Gtk+ library by Peter Mattis <petm@xcf.berkeley.edu>
*/
/**
* SECTION:signals
* @Short_description: A means for customization of object behaviour and a general purpose notification mechanism
* @Title: Signals
*
* The basic concept of the signal system is that of the <emphasis>emission</emphasis>
* of a signal.
* Signals are introduced per-type and are identified through strings.
* Signals introduced for a parent type are available in derived types as well,
* so basically they are a per-type facility that is inherited.
* A signal emission mainly involves invocation of a certain set of callbacks in
* precisely defined manner. There are two main categories of such callbacks,
* per-object
* i'm referring to those types as "object types" in the following, simply
* because that is the context most users will encounter signals in.
*
* ones and user provided ones.
* The per-object callbacks are most often referred to as "object method
* handler" or "default (signal) handler", while user provided callbacks are
* usually just called "signal handler".
* The object method handler is provided at signal creation time (this most
* frequently happens at the end of an object class' creation), while user
* provided handlers are frequently connected and disconnected to/from a certain
* signal on certain object instances.
*
* A signal emission consists of five stages, unless prematurely stopped:
* <variablelist>
* <varlistentry><term></term><listitem><para>
* 1 - Invocation of the object method handler for %G_SIGNAL_RUN_FIRST signals
* </para></listitem></varlistentry>
* <varlistentry><term></term><listitem><para>
* 2 - Invocation of normal user-provided signal handlers (<emphasis>after</emphasis> flag %FALSE)
* </para></listitem></varlistentry>
* <varlistentry><term></term><listitem><para>
* 3 - Invocation of the object method handler for %G_SIGNAL_RUN_LAST signals
* </para></listitem></varlistentry>
* <varlistentry><term></term><listitem><para>
* 4 - Invocation of user provided signal handlers, connected with an <emphasis>after</emphasis> flag of %TRUE
* </para></listitem></varlistentry>
* <varlistentry><term></term><listitem><para>
* 5 - Invocation of the object method handler for %G_SIGNAL_RUN_CLEANUP signals
* </para></listitem></varlistentry>
* </variablelist>
* The user-provided signal handlers are called in the order they were
* connected in.
* All handlers may prematurely stop a signal emission, and any number of
* handlers may be connected, disconnected, blocked or unblocked during
* a signal emission.
* There are certain criteria for skipping user handlers in stages 2 and 4
* of a signal emission.
* First, user handlers may be <emphasis>blocked</emphasis>, blocked handlers are omitted
* during callback invocation, to return from the "blocked" state, a
* handler has to get unblocked exactly the same amount of times
* it has been blocked before.
* Second, upon emission of a %G_SIGNAL_DETAILED signal, an additional
* "detail" argument passed in to g_signal_emit() has to match the detail
* argument of the signal handler currently subject to invocation.
* Specification of no detail argument for signal handlers (omission of the
* detail part of the signal specification upon connection) serves as a
* wildcard and matches any detail argument passed in to emission.
*/
/*
* MT safe
*/
@ -746,6 +806,20 @@ _g_signals_destroy (GType itype)
SIGNAL_UNLOCK ();
}
/**
* g_signal_stop_emission:
* @instance: the object whose signal handlers you wish to stop.
* @signal_id: the signal identifier, as returned by g_signal_lookup().
* @detail: the detail which the signal was emitted with.
*
* Stops a signal's current emission.
*
* This will prevent the default method from running, if the signal was
* %G_SIGNAL_RUN_LAST and you connected normally (i.e. without the "after"
* flag).
*
* Prints a warning if used on a signal which isn't being emitted.
*/
void
g_signal_stop_emission (gpointer instance,
guint signal_id,
@ -801,6 +875,20 @@ signal_finalize_hook (GHookList *hook_list,
}
}
/**
* g_signal_add_emission_hook:
* @signal_id: the signal identifier, as returned by g_signal_lookup().
* @detail: the detail on which to call the hook.
* @hook_func: a #GSignalEmissionHook function.
* @hook_data: user data for @hook_func.
* @data_destroy: a #GDestroyNotify for @hook_data.
*
* Adds an emission hook for a signal, which will get called for any emission
* of that signal, independent of the instance. This is possible only
* for signals which don't have #G_SIGNAL_NO_HOOKS flag set.
*
* Returns: the hook id, for later use with g_signal_remove_emission_hook().
*/
gulong
g_signal_add_emission_hook (guint signal_id,
GQuark detail,
@ -856,6 +944,14 @@ g_signal_add_emission_hook (guint signal_id,
return hook->hook_id;
}
/**
* g_signal_remove_emission_hook:
* @signal_id: the id of the signal
* @hook_id: the id of the emission hook, as returned by
* g_signal_add_emission_hook()
*
* Deletes an emission hook.
*/
void
g_signal_remove_emission_hook (guint signal_id,
gulong hook_id)
@ -918,6 +1014,19 @@ signal_parse_name (const gchar *name,
return signal_id;
}
/**
* g_signal_parse_name:
* @detailed_signal: a string of the form "signal-name::detail".
* @itype: The interface/instance type that introduced "signal-name".
* @signal_id_p: Location to store the signal id.
* @detail_p: Location to store the detail quark.
* @force_detail_quark: %TRUE forces creation of a #GQuark for the detail.
*
* Internal function to parse a signal name into its @signal_id
* and @detail quark.
*
* Returns: Whether the signal name could successfully be parsed and @signal_id_p and @detail_p contain valid return values.
*/
gboolean
g_signal_parse_name (const gchar *detailed_signal,
GType itype,
@ -949,6 +1058,16 @@ g_signal_parse_name (const gchar *detailed_signal,
return TRUE;
}
/**
* g_signal_stop_emission_by_name:
* @instance: the object whose signal handlers you wish to stop.
* @detailed_signal: a string of the form "signal-name::detail".
*
* Stops a signal's current emission.
*
* This is just like g_signal_stop_emission() except it will look up the
* signal id for you.
*/
void
g_signal_stop_emission_by_name (gpointer instance,
const gchar *detailed_signal)
@ -994,6 +1113,21 @@ g_signal_stop_emission_by_name (gpointer instance,
SIGNAL_UNLOCK ();
}
/**
* g_signal_lookup:
* @name: the signal's name.
* @itype: the type that the signal operates on.
*
* Given the name of the signal and the type of object it connects to, gets
* the signal's identifying integer. Emitting the signal by number is
* somewhat faster than using the name each time.
*
* Also tries the ancestors of the given type.
*
* See g_signal_new() for details on allowed signal names.
*
* Returns: the signal's identifying number, or 0 if no signal was found.
*/
guint
g_signal_lookup (const gchar *name,
GType itype)
@ -1022,6 +1156,17 @@ g_signal_lookup (const gchar *name,
return signal_id;
}
/**
* g_signal_list_ids:
* @itype: Instance or interface type.
* @n_ids: Location to store the number of signal ids for @itype.
*
* Lists the signals by id that a certain instance or interface type
* created. Further information about the signals can be acquired through
* g_signal_query().
*
* Returns: Newly allocated array of signal IDs.
*/
guint*
g_signal_list_ids (GType itype,
guint *n_ids)
@ -1069,6 +1214,16 @@ g_signal_list_ids (GType itype,
return (guint*) g_array_free (result, FALSE);
}
/**
* g_signal_name:
* @signal_id: the signal's identifying number.
*
* Given the signal's identifier, finds its name.
*
* Two different signals may have the same name, if they have differing types.
*
* Returns: the signal name, or %NULL if the signal number was invalid.
*/
G_CONST_RETURN gchar*
g_signal_name (guint signal_id)
{
@ -1083,6 +1238,19 @@ g_signal_name (guint signal_id)
return (char*) name;
}
/**
* g_signal_query:
* @signal_id: The signal id of the signal to query information for.
* @query: A user provided structure that is filled in with constant
* values upon success.
*
* Queries the signal system for in-depth information about a
* specific signal. This function will fill in a user-provided
* structure to hold signal-specific information. If an invalid
* signal id is passed in, the @signal_id member of the #GSignalQuery
* is 0. All members filled into the #GSignalQuery structure should
* be considered constant and have to be left untouched.
*/
void
g_signal_query (guint signal_id,
GSignalQuery *query)
@ -1108,6 +1276,38 @@ g_signal_query (guint signal_id,
SIGNAL_UNLOCK ();
}
/**
* g_signal_new:
* @signal_name: the name for the signal
* @itype: the type this signal pertains to. It will also pertain to
* types which are derived from this type.
* @signal_flags: a combination of #GSignalFlags specifying detail of when
* the default handler is to be invoked. You should at least specify
* %G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST.
* @class_offset: The offset of the function pointer in the class structure
* for this type. Used to invoke a class method generically. Pass 0 to
* not associate a class method with this signal.
* @accumulator: the accumulator for this signal; may be %NULL.
* @accu_data: user data for the @accumulator.
* @c_marshaller: the function to translate arrays of parameter values to
* signal emissions into C language callback invocations.
* @return_type: the type of return value, or #G_TYPE_NONE for a signal
* without a return value.
* @n_params: the number of parameter types to follow.
* @...: a list of types, one for each parameter.
*
* Creates a new signal. (This is usually done in the class initializer.)
*
* A signal name consists of segments consisting of ASCII letters and
* digits, separated by either the '-' or '_' character. The first
* character of a signal name must be a letter. Names which violate these
* rules lead to undefined behaviour of the GSignal system.
*
* When registering a signal and looking up a signal, either separator can
* be used, but they cannot be mixed.
*
* Returns: the signal id
*/
guint
g_signal_new (const gchar *signal_name,
GType itype,
@ -1210,6 +1410,30 @@ signal_add_class_closure (SignalNode *node,
g_closure_set_marshal (closure, node->c_marshaller);
}
/**
* g_signal_newv:
* @signal_name: the name for the signal
* @itype: the type this signal pertains to. It will also pertain to
* types which are derived from this type.
* @signal_flags: a combination of #GSignalFlags specifying detail of when
* the default handler is to be invoked. You should at least specify
* %G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST.
* @class_closure: The closure to invoke on signal emission; may be %NULL.
* @accumulator: the accumulator for this signal; may be %NULL.
* @accu_data: user data for the @accumulator.
* @c_marshaller: the function to translate arrays of parameter values to
* signal emissions into C language callback invocations.
* @return_type: the type of return value, or #G_TYPE_NONE for a signal
* without a return value.
* @n_params: the length of @param_types.
* @param_types: an array types, one for each parameter.
*
* Creates a new signal. (This is usually done in the class initializer.)
*
* See g_signal_new() for details on allowed signal names.
*
* Returns: the signal id
*/
guint
g_signal_newv (const gchar *signal_name,
GType itype,
@ -1344,6 +1568,30 @@ g_signal_newv (const gchar *signal_name,
return signal_id;
}
/**
* g_signal_new_valist:
* @signal_name: the name for the signal
* @itype: the type this signal pertains to. It will also pertain to
* types which are derived from this type.
* @signal_flags: a combination of #GSignalFlags specifying detail of when
* the default handler is to be invoked. You should at least specify
* %G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST.
* @class_closure: The closure to invoke on signal emission; may be %NULL.
* @accumulator: the accumulator for this signal; may be %NULL.
* @accu_data: user data for the @accumulator.
* @c_marshaller: the function to translate arrays of parameter values to
* signal emissions into C language callback invocations.
* @return_type: the type of return value, or #G_TYPE_NONE for a signal
* without a return value.
* @n_params: the number of parameter types in @args.
* @args: va_list of #GType, one for each parameter.
*
* Creates a new signal. (This is usually done in the class initializer.)
*
* See g_signal_new() for details on allowed signal names.
*
* Returns: the signal id
*/
guint
g_signal_new_valist (const gchar *signal_name,
GType itype,
@ -1433,6 +1681,17 @@ signal_destroy_R (SignalNode *signal_node)
SIGNAL_LOCK ();
}
/**
* g_signal_override_class_closure:
* @signal_id: the signal id
* @instance_type: the instance type on which to override the class closure
* for the signal.
* @class_closure: the closure.
*
* Overrides the class closure (i.e. the default handler) for the given signal
* for emissions on instances of @instance_type. @instance_type must be derived
* from the type to which the signal belongs.
*/
void
g_signal_override_class_closure (guint signal_id,
GType instance_type,
@ -1459,6 +1718,17 @@ g_signal_override_class_closure (guint signal_id,
SIGNAL_UNLOCK ();
}
/**
* g_signal_chain_from_overridden:
* @instance_and_params: the argument list of the signal emission. The first
* element in the array is a #GValue for the instance the signal is being
* emitted on. The rest are any arguments to be passed to the signal.
* @return_value: Location for the return value.
*
* Calls the original class closure of a signal. This function should only
* be called from an overridden class closure; see
* g_signal_override_class_closure().
*/
void
g_signal_chain_from_overridden (const GValue *instance_and_params,
GValue *return_value)
@ -1518,6 +1788,14 @@ g_signal_chain_from_overridden (const GValue *instance_and_params,
SIGNAL_UNLOCK ();
}
/**
* g_signal_get_invocation_hint:
* @instance: the instance to query
*
* Returns the invocation hint of the innermost signal emission of instance.
*
* Returns: the invocation hint of the innermost signal emission.
*/
GSignalInvocationHint*
g_signal_get_invocation_hint (gpointer instance)
{
@ -1532,6 +1810,19 @@ g_signal_get_invocation_hint (gpointer instance)
return emission ? &emission->ihint : NULL;
}
/**
* g_signal_connect_closure_by_id:
* @instance: the instance to connect to.
* @signal_id: the id of the signal.
* @detail: the detail.
* @closure: the closure to connect.
* @after: whether the handler should be called before or after the
* default handler of the signal.
*
* Connects a closure to a signal for a particular object.
*
* Returns: the handler id
*/
gulong
g_signal_connect_closure_by_id (gpointer instance,
guint signal_id,
@ -1574,6 +1865,18 @@ g_signal_connect_closure_by_id (gpointer instance,
return handler_seq_no;
}
/**
* g_signal_connect_closure:
* @instance: the instance to connect to.
* @detailed_signal: a string of the form "signal-name::detail".
* @closure: the closure to connect.
* @after: whether the handler should be called before or after the
* default handler of the signal.
*
* Connects a closure to a signal for a particular object.
*
* Returns: the handler id
*/
gulong
g_signal_connect_closure (gpointer instance,
const gchar *detailed_signal,
@ -1620,6 +1923,23 @@ g_signal_connect_closure (gpointer instance,
return handler_seq_no;
}
/**
* g_signal_connect_data:
* @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.
* @destroy_data: a #GClosureNotify for @data.
* @connect_flags: a combination of #GConnectFlags.
*
* Connects a #GCallback function to a signal for a particular object. Similar
* to g_signal_connect(), but allows to provide a #GClosureNotify for the data
* which will be called when the signal handler is disconnected and no longer
* used. Specify @connect_flags if you need <literal>..._after()</literal> or
* <literal>..._swapped()</literal> variants of this function.
*
* Returns: the handler id
*/
gulong
g_signal_connect_data (gpointer instance,
const gchar *detailed_signal,
@ -1672,6 +1992,20 @@ g_signal_connect_data (gpointer instance,
return handler_seq_no;
}
/**
* g_signal_handler_block:
* @instance: The instance to block the signal handler of.
* @handler_id: Handler id of the handler to be blocked.
*
* Blocks a handler of an instance so it will not be called during
* any signal emissions unless it is unblocked again. Thus "blocking"
* a signal handler means to temporarily deactive it, a signal handler
* has to be unblocked exactly the same amount of times it has been
* blocked before to become active again.
*
* The @handler_id has to be a valid signal handler id, connected to a
* signal of @instance.
*/
void
g_signal_handler_block (gpointer instance,
gulong handler_id)
@ -1696,6 +2030,25 @@ g_signal_handler_block (gpointer instance,
SIGNAL_UNLOCK ();
}
/**
* g_signal_handler_unblock:
* @instance: The instance to unblock the signal handler of.
* @handler_id: Handler id of the handler to be unblocked.
*
* Undoes the effect of a previous g_signal_handler_block() call.
* A blocked handler is skipped during signal emissions and will not be
* invoked, unblocking it (for exactly the amount of times it has been
* blocked before) reverts its "blocked" state, so the handler will be
* recognized by the signal system and is called upon future or currently
* ongoing signal emissions (since the order in which handlers are
* called during signal emissions is deterministic, whether the
* unblocked handler in question is called as part of a currently
* ongoing emission depends on how far that emission has proceeded
* yet).
*
* The @handler_id has to be a valid id of a signal handler that is
* connected to a signal of @instance and is currently blocked.
*/
void
g_signal_handler_unblock (gpointer instance,
gulong handler_id)
@ -1719,6 +2072,18 @@ g_signal_handler_unblock (gpointer instance,
SIGNAL_UNLOCK ();
}
/**
* g_signal_handler_disconnect:
* @instance: The instance to remove the signal handler from.
* @handler_id: Handler id of the handler to be disconnected.
*
* Disconnects a handler from an instance so it will not be called during
* any future or currently ongoing emissions of the signal it has been
* connected to. The @handler_id becomes invalid and may be reused.
*
* The @handler_id has to be a valid signal handler id, connected to a
* signal of @instance.
*/
void
g_signal_handler_disconnect (gpointer instance,
gulong handler_id)
@ -1742,6 +2107,15 @@ g_signal_handler_disconnect (gpointer instance,
SIGNAL_UNLOCK ();
}
/**
* g_signal_handler_is_connected:
* @instance: The instance where a signal handler is sought.
* @handler_id: the handler id.
*
* Returns whether @handler_id is the id of a handler connected to @instance.
*
* Returns: whether @handler_id identifies a handler connected to @instance.
*/
gboolean
g_signal_handler_is_connected (gpointer instance,
gulong handler_id)
@ -1801,6 +2175,25 @@ g_signal_handlers_destroy (gpointer instance)
SIGNAL_UNLOCK ();
}
/**
* g_signal_handler_find:
* @instance: The instance owning the signal handler to be found.
* @mask: Mask indicating which of @signal_id, @detail, @closure, @func
* and/or @data the handler has to match.
* @signal_id: Signal the handler has to be connected to.
* @detail: Signal detail the handler has to be connected to.
* @closure: The closure the handler will invoke.
* @func: The C closure callback of the handler (useless for non-C closures).
* @data: The closure data of the handler's closure.
*
* Finds the first signal handler that matches certain selection criteria.
* The criteria mask is passed as an OR-ed combination of #GSignalMatchType
* flags, and the criteria values are passed as arguments.
* The match @mask has to be non-0 for successful matches.
* If no handler was found, 0 is returned.
*
* Returns: A valid non-0 signal handler id for a successful match.
*/
gulong
g_signal_handler_find (gpointer instance,
GSignalMatchType mask,
@ -1862,6 +2255,27 @@ signal_handlers_foreach_matched_R (gpointer instance,
return n_handlers;
}
/**
* g_signal_handlers_block_matched:
* @instance: The instance to block handlers from.
* @mask: Mask indicating which of @signal_id, @detail, @closure, @func
* and/or @data the handlers have to match.
* @signal_id: Signal the handlers have to be connected to.
* @detail: Signal detail the handlers have to be connected to.
* @closure: The closure the handlers will invoke.
* @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 a certain selection criteria.
* The criteria mask is passed as an OR-ed combination of #GSignalMatchType
* flags, and the criteria values are passed as arguments.
* Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
* or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
* If no handlers were found, 0 is returned, the number of blocked handlers
* otherwise.
*
* Returns: The number of handlers that matched.
*/
guint
g_signal_handlers_block_matched (gpointer instance,
GSignalMatchType mask,
@ -1888,6 +2302,28 @@ g_signal_handlers_block_matched (gpointer instance,
return n_handlers;
}
/**
* g_signal_handlers_unblock_matched:
* @instance: The instance to unblock handlers from.
* @mask: Mask indicating which of @signal_id, @detail, @closure, @func
* and/or @data the handlers have to match.
* @signal_id: Signal the handlers have to be connected to.
* @detail: Signal detail the handlers have to be connected to.
* @closure: The closure the handlers will invoke.
* @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 a certain selection
* criteria. The criteria mask is passed as an OR-ed combination of
* #GSignalMatchType flags, and the criteria values are passed as arguments.
* Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
* or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
* If no handlers were found, 0 is returned, the number of unblocked handlers
* otherwise. The match criteria should not apply to any handlers that are
* not currently blocked.
*
* Returns: The number of handlers that matched.
*/
guint
g_signal_handlers_unblock_matched (gpointer instance,
GSignalMatchType mask,
@ -1914,6 +2350,27 @@ g_signal_handlers_unblock_matched (gpointer instance,
return n_handlers;
}
/**
* g_signal_handlers_disconnect_matched:
* @instance: The instance to remove handlers from.
* @mask: Mask indicating which of @signal_id, @detail, @closure, @func
* and/or @data the handlers have to match.
* @signal_id: Signal the handlers have to be connected to.
* @detail: Signal detail the handlers have to be connected to.
* @closure: The closure the handlers will invoke.
* @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 a certain selection
* criteria. The criteria mask is passed as an OR-ed combination of
* #GSignalMatchType flags, and the criteria values are passed as arguments.
* Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
* or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
* If no handlers were found, 0 is returned, the number of disconnected
* handlers otherwise.
*
* Returns: The number of handlers that matched.
*/
guint
g_signal_handlers_disconnect_matched (gpointer instance,
GSignalMatchType mask,
@ -1940,6 +2397,24 @@ g_signal_handlers_disconnect_matched (gpointer instance,
return n_handlers;
}
/**
* g_signal_has_handler_pending:
* @instance: the object whose signal handlers are sought.
* @signal_id: the signal id.
* @detail: the detail.
* @may_be_blocked: whether blocked handlers should count as match.
*
* Returns whether there are any handlers connected to @instance for the
* given signal id and detail.
*
* One example of when you might use this is when the arguments to the
* signal are difficult to compute. A class implementor may opt to not emit
* the signal if no one is attached anyway, thus saving the cost of building
* the arguments.
*
* Returns: %TRUE if a handler is connected to the signal,
* %FALSE otherwise.
*/
gboolean
g_signal_has_handler_pending (gpointer instance,
guint signal_id,
@ -2023,6 +2498,21 @@ signal_check_skip_emission (SignalNode *node,
return TRUE;
}
/**
* g_signal_emitv:
* @instance_and_params: argument list for the signal emission. The first
* element in the array is a #GValue for the instance the signal is
* being emitted on. The rest are any arguments to be passed to the
* signal.
* @signal_id: the signal id
* @detail: the detail
* @return_value: Location to store the return value of the signal emission.
*
* Emits a signal.
*
* Note that g_signal_emitv() doesn't change @return_value if no handlers are
* connected, in contrast to g_signal_emit() and g_signal_emit_valist().
*/
void
g_signal_emitv (const GValue *instance_and_params,
guint signal_id,
@ -2111,6 +2601,20 @@ g_signal_emitv (const GValue *instance_and_params,
signal_emit_unlocked_R (node, detail, instance, return_value, instance_and_params);
}
/**
* g_signal_emit_valist:
* @instance: the instance the signal is being emitted on.
* @signal_id: the signal id
* @detail: the detail
* @var_args: a list of parameters to be passed to the signal, followed by a
* location for the return value. If the return type of the signal
* is #G_TYPE_NONE, the return value location can be omitted.
*
* Emits a signal.
*
* Note that g_signal_emit_valist() resets the return value to the default
* if no handlers are connected, in contrast to g_signal_emitv().
*/
void
g_signal_emit_valist (gpointer instance,
guint signal_id,
@ -2231,6 +2735,20 @@ g_signal_emit_valist (gpointer instance,
g_free (free_me);
}
/**
* g_signal_emit:
* @instance: the instance the signal is being emitted on.
* @signal_id: the signal id
* @detail: the detail
* @...: parameters to be passed to the signal, followed by a
* location for the return value. If the return type of the signal
* is #G_TYPE_NONE, the return value location can be omitted.
*
* Emits a signal.
*
* Note that g_signal_emit() resets the return value to the default
* if no handlers are connected, in contrast to g_signal_emitv().
*/
void
g_signal_emit (gpointer instance,
guint signal_id,
@ -2244,6 +2762,19 @@ g_signal_emit (gpointer instance,
va_end (var_args);
}
/**
* g_signal_emit_by_name:
* @instance: the instance the signal is being emitted on.
* @detailed_signal: a string of the form "signal-name::detail".
* @...: parameters to be passed to the signal, followed by a
* location for the return value. If the return type of the signal
* is #G_TYPE_NONE, the return value location can be omitted.
*
* Emits a signal.
*
* Note that g_signal_emit_by_name() resets the return value to the default
* if no handlers are connected, in contrast to g_signal_emitv().
*/
void
g_signal_emit_by_name (gpointer instance,
const gchar *detailed_signal,
@ -2590,6 +3121,24 @@ type_debug_name (GType type)
return "<invalid>";
}
/**
* g_signal_accumulator_true_handled:
* @ihint: standard #GSignalAccumulator parameter
* @return_accu: standard #GSignalAccumulator parameter
* @handler_return: standard #GSignalAccumulator parameter
* @dummy: standard #GSignalAccumulator parameter
*
* A predefined #GSignalAccumulator for signals that return a
* boolean values. The behavior that this accumulator gives is
* that a return of %TRUE stops the signal emission: no further
* callbacks will be invoked, while a return of %FALSE allows
* the emission to coninue. The idea here is that a %TRUE return
* indicates that the callback <emphasis>handled</emphasis> the signal,
* and no further handling is needed.
*
* Since: 2.4
* Returns: standard #GSignalAccumulator result
*/
gboolean
g_signal_accumulator_true_handled (GSignalInvocationHint *ihint,
GValue *return_accu,

223
gobject/gsignal.h
View File

@ -33,11 +33,57 @@ 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;
/**
* 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: 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,
@ -45,6 +91,28 @@ typedef gboolean (*GSignalAccumulator) (GSignalInvocationHint *ihint,
/* --- 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.
*
* 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,
@ -55,12 +123,40 @@ typedef enum
G_SIGNAL_ACTION = 1 << 5,
G_SIGNAL_NO_HOOKS = 1 << 6
} GSignalFlags;
/**
* G_SIGNAL_FLAGS_MASK:
*
* A mask for all #GSignalFlags bits.
*/
#define G_SIGNAL_FLAGS_MASK 0x7f
/**
* 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.
*
* 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 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 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,
@ -70,17 +166,74 @@ typedef enum
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
* <literal>| G_SIGNAL_TYPE_STATIC_SCOPE</literal> 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.
*
* 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: The individual parameter types for user callbacks, note that the
* effective callback signature is:
* <programlisting>
* @return_type callback (#gpointer data1,
* [#param_types param_names,]
* #gpointer data2);
* </programlisting>
*
* 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;
@ -236,20 +389,90 @@ void g_signal_chain_from_overridden (const GValue *instance_and_param
/* --- 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.
*
* Returns: the handler id
*/
#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
*/
#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.
*
* Returns: the handler id
*/
#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_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), \