:right-sidebar: True Source =================================================================== .. currentmodule:: gi.repository.GLib .. class:: Source(*args, **kwargs) :no-contents-entry: The ``GSource`` struct is an opaque data type representing an event source. Constructors ------------ .. rst-class:: interim-class .. class:: Source :no-index: .. classmethod:: new(source_funcs: ~gi.repository.GLib.SourceFuncs, struct_size: int) -> ~gi.repository.GLib.Source Creates a new :obj:`~gi.repository.GLib.Source` structure. The size is specified to allow creating structures derived from :obj:`~gi.repository.GLib.Source` that contain additional data. The size passed in must be at least ``sizeof (GSource)``\. The source will not initially be associated with any :obj:`~gi.repository.GLib.MainContext` and must be added to one with :obj:`~gi.repository.GLib.Source.attach` before it will be executed. :param source_funcs: structure containing functions that implement the sources behavior. :param struct_size: size of the :obj:`~gi.repository.GLib.Source` structure to create. Methods ------- .. rst-class:: interim-class .. class:: Source :no-index: .. method:: add_child_source(child_source: ~gi.repository.GLib.Source) -> None Adds ``child_source`` to ``source`` as a "polled" source; when ``source`` is added to a :obj:`~gi.repository.GLib.MainContext`\, ``child_source`` will be automatically added with the same priority, when ``child_source`` is triggered, it will cause ``source`` to dispatch (in addition to calling its own callback), and when ``source`` is destroyed, it will destroy ``child_source`` as well. (``source`` will also still be dispatched if its own prepare/check functions indicate that it is ready.) If you don't need ``child_source`` to do anything on its own when it triggers, you can call g_source_set_dummy_callback() on it to set a callback that does nothing (except return :const:`True` if appropriate). ``source`` will hold a reference on ``child_source`` while ``child_source`` is attached to it. This API is only intended to be used by implementations of :obj:`~gi.repository.GLib.Source`\. Do not call this API on a :obj:`~gi.repository.GLib.Source` that you did not create. .. versionadded:: 2.28 :param child_source: a second :obj:`~gi.repository.GLib.Source` that ``source`` should "poll" .. method:: add_poll(fd: ~gi.repository.GLib.PollFD) -> None Adds a file descriptor to the set of file descriptors polled for this source. This is usually combined with :obj:`~gi.repository.GLib.Source.new` to add an event source. The event source's check function will typically test the ``revents`` field in the :obj:`~gi.repository.GLib.PollFD` struct and return :const:`True` if events need to be processed. This API is only intended to be used by implementations of :obj:`~gi.repository.GLib.Source`\. Do not call this API on a :obj:`~gi.repository.GLib.Source` that you did not create. Using this API forces the linear scanning of event sources on each main loop iteration. Newly-written event sources should try to use ``g_source_add_unix_fd`` instead of this API. :param fd: a :obj:`~gi.repository.GLib.PollFD` structure holding information about a file descriptor to watch. .. method:: add_unix_fd(fd: int, events: ~gi.repository.GLib.IOCondition) -> ~typing.Any Monitors ``fd`` for the IO events in ``events``\. The tag returned by this function can be used to remove or modify the monitoring of the fd using :obj:`~gi.repository.GLib.Source.remove_unix_fd` or :obj:`~gi.repository.GLib.Source.modify_unix_fd`\. It is not necessary to remove the fd before destroying the source; it will be cleaned up automatically. This API is only intended to be used by implementations of :obj:`~gi.repository.GLib.Source`\. Do not call this API on a :obj:`~gi.repository.GLib.Source` that you did not create. As the name suggests, this function is not available on Windows. .. versionadded:: 2.36 :param fd: the fd to monitor :param events: an event mask .. method:: attach(context: ~gi.repository.GLib.MainContext | None = None) -> int Adds a :obj:`~gi.repository.GLib.Source` to a ``context`` so that it will be executed within that context. Remove it by calling :obj:`~gi.repository.GLib.Source.destroy`\. This function is safe to call from any thread, regardless of which thread the ``context`` is running in. :param context: a :obj:`~gi.repository.GLib.MainContext` (if :const:`None`, the global-default main context will be used) .. method:: destroy() -> None Removes a source from its :obj:`~gi.repository.GLib.MainContext`\, if any, and mark it as destroyed. The source cannot be subsequently added to another context. It is safe to call this on sources which have already been removed from their context. This does not unref the :obj:`~gi.repository.GLib.Source`\: if you still hold a reference, use :obj:`~gi.repository.GLib.Source.unref` to drop it. This function is safe to call from any thread, regardless of which thread the :obj:`~gi.repository.GLib.MainContext` is running in. If the source is currently attached to a :obj:`~gi.repository.GLib.MainContext`\, destroying it will effectively unset the callback similar to calling :obj:`~gi.repository.GLib.Source.set_callback`\. This can mean, that the data's :obj:`~gi.repository.GLib.DestroyNotify` gets called right away. .. method:: finalize() .. method:: get_can_recurse() -> bool Checks whether a source is allowed to be called recursively. see :obj:`~gi.repository.GLib.Source.set_can_recurse`\. .. method:: get_context() -> ~gi.repository.GLib.MainContext | None Gets the :obj:`~gi.repository.GLib.MainContext` with which the source is associated. You can call this on a source that has been destroyed, provided that the :obj:`~gi.repository.GLib.MainContext` it was attached to still exists (in which case it will return that :obj:`~gi.repository.GLib.MainContext`\). In particular, you can always call this function on the source returned from :obj:`~gi.repository.GLib.main_current_source`\. But calling this function on a source whose :obj:`~gi.repository.GLib.MainContext` has been destroyed is an error. .. method:: get_current_time() This function ignores ``source`` and is otherwise the same as :obj:`~gi.repository.GLib.get_current_time`\. .. deprecated:: 2.28 use :obj:`~gi.repository.GLib.Source.get_time` instead .. method:: get_id() -> int Returns the numeric ID for a particular source. The ID of a source is a positive integer which is unique within a particular main loop context. The reverse mapping from ID to source is done by :obj:`~gi.repository.GLib.MainContext.find_source_by_id`\. You can only call this function while the source is associated to a :obj:`~gi.repository.GLib.MainContext` instance; calling this function before :obj:`~gi.repository.GLib.Source.attach` or after :obj:`~gi.repository.GLib.Source.destroy` yields undefined behavior. The ID returned is unique within the :obj:`~gi.repository.GLib.MainContext` instance passed to :obj:`~gi.repository.GLib.Source.attach`\. .. method:: get_name() -> str | None Gets a name for the source, used in debugging and profiling. The name may be :obj:`~gi.repository.None` if it has never been set with :obj:`~gi.repository.GLib.Source.set_name`\. .. versionadded:: 2.26 .. method:: get_priority() -> int Gets the priority of a source. .. method:: get_ready_time() -> int Gets the "ready time" of ``source``\, as set by :obj:`~gi.repository.GLib.Source.set_ready_time`\. Any time before or equal to the current monotonic time (including 0) is an indication that the source will fire immediately. .. method:: get_time() -> int Gets the time to be used when checking this source. The advantage of calling this function over calling :obj:`~gi.repository.GLib.get_monotonic_time` directly is that when checking multiple sources, GLib can cache a single value instead of having to repeatedly get the system monotonic time. The time here is the system monotonic time, if available, or some other reasonable alternative otherwise. See :obj:`~gi.repository.GLib.get_monotonic_time`\. .. versionadded:: 2.28 .. method:: is_destroyed() -> bool Returns whether ``source`` has been destroyed. This is important when you operate upon your objects from within idle handlers, but may have freed the object before the dispatch of your idle handler. .. code-block:: C :dedent: static gboolean idle_callback (gpointer data) { SomeWidget *self = data; g_mutex_lock (&self->idle_id_mutex); // do stuff with self self->idle_id = 0; g_mutex_unlock (&self->idle_id_mutex); return G_SOURCE_REMOVE; } static void some_widget_do_stuff_later (SomeWidget *self) { g_mutex_lock (&self->idle_id_mutex); self->idle_id = g_idle_add (idle_callback, self); g_mutex_unlock (&self->idle_id_mutex); } static void some_widget_init (SomeWidget *self) { g_mutex_init (&self->idle_id_mutex); // ... } static void some_widget_finalize (GObject *object) { SomeWidget *self = SOME_WIDGET (object); if (self->idle_id) g_source_remove (self->idle_id); g_mutex_clear (&self->idle_id_mutex); G_OBJECT_CLASS (parent_class)->finalize (object); } This will fail in a multi-threaded application if the widget is destroyed before the idle handler fires due to the use after free in the callback. A solution, to this particular problem, is to check to if the source has already been destroy within the callback. .. code-block:: C :dedent: static gboolean idle_callback (gpointer data) { SomeWidget *self = data; g_mutex_lock (&self->idle_id_mutex); if (!g_source_is_destroyed (g_main_current_source ())) { // do stuff with self } g_mutex_unlock (&self->idle_id_mutex); return FALSE; } Calls to this function from a thread other than the one acquired by the :obj:`~gi.repository.GLib.MainContext` the :obj:`~gi.repository.GLib.Source` is attached to are typically redundant, as the source could be destroyed immediately after this function returns. However, once a source is destroyed it cannot be un-destroyed, so this function can be used for opportunistic checks from any thread. .. versionadded:: 2.12 .. method:: modify_unix_fd(tag: ~typing.Any, new_events: ~gi.repository.GLib.IOCondition) -> None Updates the event mask to watch for the fd identified by ``tag``\. ``tag`` is the tag returned from :obj:`~gi.repository.GLib.Source.add_unix_fd`\. If you want to remove a fd, don't set its event mask to zero. Instead, call :obj:`~gi.repository.GLib.Source.remove_unix_fd`\. This API is only intended to be used by implementations of :obj:`~gi.repository.GLib.Source`\. Do not call this API on a :obj:`~gi.repository.GLib.Source` that you did not create. As the name suggests, this function is not available on Windows. .. versionadded:: 2.36 :param tag: the tag from :obj:`~gi.repository.GLib.Source.add_unix_fd` :param new_events: the new event mask to watch .. method:: query_unix_fd(tag: ~typing.Any) -> ~gi.repository.GLib.IOCondition Queries the events reported for the fd corresponding to ``tag`` on ``source`` during the last poll. The return value of this function is only defined when the function is called from the check or dispatch functions for ``source``\. This API is only intended to be used by implementations of :obj:`~gi.repository.GLib.Source`\. Do not call this API on a :obj:`~gi.repository.GLib.Source` that you did not create. As the name suggests, this function is not available on Windows. .. versionadded:: 2.36 :param tag: the tag from :obj:`~gi.repository.GLib.Source.add_unix_fd` .. classmethod:: remove() -> bool Removes the source with the given ID from the default main context. You must use :obj:`~gi.repository.GLib.Source.destroy` for sources added to a non-default main context. The ID of a :obj:`~gi.repository.GLib.Source` is given by :obj:`~gi.repository.GLib.Source.get_id`\, or will be returned by the functions :obj:`~gi.repository.GLib.Source.attach`\, :obj:`~gi.repository.GLib.idle_add`\, :obj:`~gi.repository.GLib.idle_add_full`\, :obj:`~gi.repository.GLib.timeout_add`\, :obj:`~gi.repository.GLib.timeout_add_full`\, :obj:`~gi.repository.GLib.child_watch_add`\, :obj:`~gi.repository.GLib.child_watch_add_full`\, :obj:`~gi.repository.GLib.io_add_watch`\, and :obj:`~gi.repository.GLib.io_add_watch_full`\. It is a programmer error to attempt to remove a non-existent source. More specifically: source IDs can be reissued after a source has been destroyed and therefore it is never valid to use this function with a source ID which may have already been removed. An example is when scheduling an idle to run in another thread with :obj:`~gi.repository.GLib.idle_add`\: the idle may already have run and been removed by the time this function is called on its (now invalid) source ID. This source ID may have been reissued, leading to the operation being performed against the wrong source. :return: 0 if the file was successfully removed, -1 if an error occurred .. classmethod:: remove_by_funcs_user_data(user_data: ~typing.Any = None) -> bool Removes a source from the default main loop context given the source functions and user data. If multiple sources exist with the same source functions and user data, only one will be destroyed. :param user_data: the user data for the callback .. classmethod:: remove_by_user_data() -> bool Removes a source from the default main loop context given the user data for the callback. If multiple sources exist with the same user data, only one will be destroyed. .. method:: remove_child_source(child_source: ~gi.repository.GLib.Source) -> None Detaches ``child_source`` from ``source`` and destroys it. This API is only intended to be used by implementations of :obj:`~gi.repository.GLib.Source`\. Do not call this API on a :obj:`~gi.repository.GLib.Source` that you did not create. .. versionadded:: 2.28 :param child_source: a :obj:`~gi.repository.GLib.Source` previously passed to :obj:`~gi.repository.GLib.Source.add_child_source`\. .. method:: remove_poll(fd: ~gi.repository.GLib.PollFD) -> None Removes a file descriptor from the set of file descriptors polled for this source. This API is only intended to be used by implementations of :obj:`~gi.repository.GLib.Source`\. Do not call this API on a :obj:`~gi.repository.GLib.Source` that you did not create. :param fd: a :obj:`~gi.repository.GLib.PollFD` structure previously passed to :obj:`~gi.repository.GLib.Source.add_poll`\. .. method:: remove_unix_fd(tag: ~typing.Any) -> None Reverses the effect of a previous call to :obj:`~gi.repository.GLib.Source.add_unix_fd`\. You only need to call this if you want to remove an fd from being watched while keeping the same source around. In the normal case you will just want to destroy the source. This API is only intended to be used by implementations of :obj:`~gi.repository.GLib.Source`\. Do not call this API on a :obj:`~gi.repository.GLib.Source` that you did not create. As the name suggests, this function is not available on Windows. .. versionadded:: 2.36 :param tag: the tag from :obj:`~gi.repository.GLib.Source.add_unix_fd` .. method:: set_callback(fn, user_data=None) Sets the callback function for a source. The callback for a source is called from the source's dispatch function. The exact type of ``func`` depends on the type of source; ie. you should not count on ``func`` being called with ``data`` as its first parameter. Cast ``func`` with :obj:`~gi.repository.GLib.SOURCE_FUNC` to avoid warnings about incompatible function types. See `mainloop memory management `__ for details on how to handle memory management of ``data``\. Typically, you won't use this function. Instead use functions specific to the type of source you are using, such as :obj:`~gi.repository.GLib.idle_add` or :obj:`~gi.repository.GLib.timeout_add`\. It is safe to call this function multiple times on a source which has already been attached to a context. The changes will take effect for the next time the source is dispatched after this call returns. Note that :obj:`~gi.repository.GLib.Source.destroy` for a currently attached source has the effect of also unsetting the callback. :param fn: :param user_data: .. method:: set_callback_indirect(callback_data: ~typing.Any, callback_funcs: ~gi.repository.GLib.SourceCallbackFuncs) -> None Sets the callback function storing the data as a refcounted callback "object". This is used internally. Note that calling :obj:`~gi.repository.GLib.Source.set_callback_indirect` assumes an initial reference count on ``callback_data``\, and thus ``callback_funcs``\->unref will eventually be called once more than ``callback_funcs``\->ref. It is safe to call this function multiple times on a source which has already been attached to a context. The changes will take effect for the next time the source is dispatched after this call returns. :param callback_data: pointer to callback data "object" :param callback_funcs: functions for reference counting ``callback_data`` and getting the callback and data .. method:: set_can_recurse(can_recurse: bool) -> None Sets whether a source can be called recursively. If ``can_recurse`` is :const:`True`, then while the source is being dispatched then this source will be processed normally. Otherwise, all processing of this source is blocked until the dispatch function returns. :param can_recurse: whether recursion is allowed for this source .. method:: set_funcs(funcs: ~gi.repository.GLib.SourceFuncs) -> None Sets the source functions (can be used to override default implementations) of an unattached source. .. versionadded:: 2.12 :param funcs: the new :obj:`~gi.repository.GLib.SourceFuncs` .. method:: set_name(name: str) -> None Sets a name for the source, used in debugging and profiling. The name defaults to :obj:`~gi.repository.None`\. The source name should describe in a human-readable way what the source does. For example, "X11 event queue" or "GTK repaint idle handler" or whatever it is. It is permitted to call this function multiple times, but is not recommended due to the potential performance impact. For example, one could change the name in the "check" function of a :obj:`~gi.repository.GLib.SourceFuncs` to include details like the event type in the source name. Use caution if changing the name while another thread may be accessing it with :obj:`~gi.repository.GLib.Source.get_name`\; that function does not copy the value, and changing the value will free it while the other thread may be attempting to use it. Also see :obj:`~gi.repository.GLib.Source.set_static_name`\. .. versionadded:: 2.26 :param name: debug name for the source .. classmethod:: set_name_by_id(name: str) -> None Sets the name of a source using its ID. This is a convenience utility to set source names from the return value of :obj:`~gi.repository.GLib.idle_add`\, :obj:`~gi.repository.GLib.timeout_add`\, etc. It is a programmer error to attempt to set the name of a non-existent source. More specifically: source IDs can be reissued after a source has been destroyed and therefore it is never valid to use this function with a source ID which may have already been removed. An example is when scheduling an idle to run in another thread with :obj:`~gi.repository.GLib.idle_add`\: the idle may already have run and been removed by the time this function is called on its (now invalid) source ID. This source ID may have been reissued, leading to the operation being performed against the wrong source. .. versionadded:: 2.26 :param name: debug name for the source .. method:: set_priority(priority: int) -> None Sets the priority of a source. While the main loop is being run, a source will be dispatched if it is ready to be dispatched and no sources at a higher (numerically smaller) priority are ready to be dispatched. A child source always has the same priority as its parent. It is not permitted to change the priority of a source once it has been added as a child of another source. :param priority: the new priority. .. method:: set_ready_time(ready_time: int) -> None Sets a :obj:`~gi.repository.GLib.Source` to be dispatched when the given monotonic time is reached (or passed). If the monotonic time is in the past (as it always will be if ``ready_time`` is 0) then the source will be dispatched immediately. If ``ready_time`` is -1 then the source is never woken up on the basis of the passage of time. Dispatching the source does not reset the ready time. You should do so yourself, from the source dispatch function. Note that if you have a pair of sources where the ready time of one suggests that it will be delivered first but the priority for the other suggests that it would be delivered first, and the ready time for both sources is reached during the same main context iteration, then the order of dispatch is undefined. It is a no-op to call this function on a :obj:`~gi.repository.GLib.Source` which has already been destroyed with :obj:`~gi.repository.GLib.Source.destroy`\. This API is only intended to be used by implementations of :obj:`~gi.repository.GLib.Source`\. Do not call this API on a :obj:`~gi.repository.GLib.Source` that you did not create. .. versionadded:: 2.36 :param ready_time: the monotonic time at which the source will be ready, 0 for "immediately", -1 for "never" .. method:: set_static_name(name: str) -> None A variant of :obj:`~gi.repository.GLib.Source.set_name` that does not duplicate the ``name``\, and can only be used with string literals. .. versionadded:: 2.70 :param name: debug name for the source Fields ------ .. rst-class:: interim-class .. class:: Source :no-index: .. attribute:: callback_data .. attribute:: callback_funcs .. attribute:: can_recurse .. attribute:: context .. attribute:: flags .. attribute:: name .. attribute:: next .. attribute:: poll_fds .. attribute:: prev .. attribute:: priority .. attribute:: priv .. attribute:: ref_count .. attribute:: source_funcs .. attribute:: source_id