Commit d15cdbef authored by Dan Winship's avatar Dan Winship

gmain: add g_source_add_child_source and g_source_remove_child_source

This adds "child source" support to GSource. A child source behaves
basically like a GPollFD; when you add a source to a context, all of
its child sources are added with the same priority; when you destroy a
source, all of its child sources are destroyed; and when a child
source triggers, its parent source's dispatch function is run.

Use cases include:

    - adding a GTimeoutSource to another source to cause the source to
      automatically trigger after a certain timeout.

    - wrapping an existing source type with a new type that has
      a different callback signature

    - creating a source that triggers based on different conditions
      at different times.

https://bugzilla.gnome.org/show_bug.cgi?id=634239
parent e9102055
......@@ -535,6 +535,8 @@ GSourceFunc
g_source_set_callback_indirect
g_source_add_poll
g_source_remove_poll
g_source_add_child_source
g_source_remove_child_source
g_source_get_time
g_source_get_current_time
g_source_remove
......
......@@ -722,6 +722,7 @@ g_main_loop_quit
g_main_loop_ref
g_main_loop_run
g_main_loop_unref
g_source_add_child_source
g_source_add_poll
g_source_attach
g_source_destroy
......@@ -739,6 +740,7 @@ g_source_ref
g_source_remove
g_source_remove_by_funcs_user_data
g_source_remove_by_user_data
g_source_remove_child_source
g_source_remove_poll
g_source_set_callback
g_source_set_callback_indirect
......
......@@ -313,6 +313,12 @@ struct _GPollRec
gint priority;
};
struct _GSourcePrivate
{
GSList *child_sources;
GSource *parent_source;
};
#ifdef G_THREADS_ENABLED
#define LOCK_CONTEXT(context) g_static_mutex_lock (&context->mutex)
#define UNLOCK_CONTEXT(context) g_static_mutex_unlock (&context->mutex)
......@@ -344,6 +350,9 @@ static void g_source_unref_internal (GSource *source,
static void g_source_destroy_internal (GSource *source,
GMainContext *context,
gboolean have_lock);
static void g_source_set_priority_unlocked (GSource *source,
GMainContext *context,
gint priority);
static void g_main_context_poll (GMainContext *context,
gint timeout,
gint priority,
......@@ -848,12 +857,21 @@ g_source_list_add (GSource *source,
{
GSource *tmp_source, *last_source;
last_source = NULL;
tmp_source = context->source_list;
while (tmp_source && tmp_source->priority <= source->priority)
if (source->priv && source->priv->parent_source)
{
/* Put the source immediately before its parent */
tmp_source = source->priv->parent_source;
last_source = source->priv->parent_source->prev;
}
else
{
last_source = tmp_source;
tmp_source = tmp_source->next;
last_source = NULL;
tmp_source = context->source_list;
while (tmp_source && tmp_source->priority <= source->priority)
{
last_source = tmp_source;
tmp_source = tmp_source->next;
}
}
source->next = tmp_source;
......@@ -885,6 +903,39 @@ g_source_list_remove (GSource *source,
source->next = NULL;
}
static guint
g_source_attach_unlocked (GSource *source,
GMainContext *context)
{
guint result = 0;
GSList *tmp_list;
source->context = context;
result = source->source_id = context->next_id++;
source->ref_count++;
g_source_list_add (source, context);
tmp_list = source->poll_fds;
while (tmp_list)
{
g_main_context_add_poll_unlocked (context, source->priority, tmp_list->data);
tmp_list = tmp_list->next;
}
if (source->priv)
{
tmp_list = source->priv->child_sources;
while (tmp_list)
{
g_source_attach_unlocked (tmp_list->data, context);
tmp_list = tmp_list->next;
}
}
return result;
}
/**
* g_source_attach:
* @source: a #GSource
......@@ -901,7 +952,6 @@ g_source_attach (GSource *source,
GMainContext *context)
{
guint result = 0;
GSList *tmp_list;
g_return_val_if_fail (source->context == NULL, 0);
g_return_val_if_fail (!SOURCE_DESTROYED (source), 0);
......@@ -911,18 +961,7 @@ g_source_attach (GSource *source,
LOCK_CONTEXT (context);
source->context = context;
result = source->source_id = context->next_id++;
source->ref_count++;
g_source_list_add (source, context);
tmp_list = source->poll_fds;
while (tmp_list)
{
g_main_context_add_poll_unlocked (context, source->priority, tmp_list->data);
tmp_list = tmp_list->next;
}
result = g_source_attach_unlocked (source, context);
#ifdef G_THREADS_ENABLED
/* Now wake up the main loop if it is waiting in the poll() */
......@@ -972,6 +1011,24 @@ g_source_destroy_internal (GSource *source,
tmp_list = tmp_list->next;
}
}
if (source->priv && source->priv->child_sources)
{
/* This is safe because even if a child_source finalizer or
* closure notify tried to modify source->priv->child_sources
* from outside the lock, it would fail since
* SOURCE_DESTROYED(source) is now TRUE.
*/
tmp_list = source->priv->child_sources;
while (tmp_list)
{
g_source_destroy_internal (tmp_list->data, context, TRUE);
g_source_unref_internal (tmp_list->data, context, TRUE);
tmp_list = tmp_list->next;
}
g_slist_free (source->priv->child_sources);
source->priv->child_sources = NULL;
}
g_source_unref_internal (source, context, TRUE);
}
......@@ -1118,6 +1175,94 @@ g_source_remove_poll (GSource *source,
}
}
/**
* g_source_add_child_source:
* @source:a #GSource
* @child_source: a second #GSource that @source should "poll"
*
* Adds @child_source to @source as a "polled" source; when @source is
* added to a #GMainContext, @child_source will be automatically added
* with the same priority, when @child_source is triggered, it will
* cause @source to dispatch (and won't call @child_source's 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 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 %TRUE if appropriate).
*
* @source will hold a reference on @child_source while @child_source
* is attached to it.
**/
void
g_source_add_child_source (GSource *source,
GSource *child_source)
{
GMainContext *context;
g_return_if_fail (source != NULL);
g_return_if_fail (child_source != NULL);
g_return_if_fail (!SOURCE_DESTROYED (source));
g_return_if_fail (!SOURCE_DESTROYED (child_source));
g_return_if_fail (child_source->context == NULL);
g_return_if_fail (child_source->priv == NULL || child_source->priv->parent_source == NULL);
context = source->context;
if (context)
LOCK_CONTEXT (context);
if (!source->priv)
source->priv = g_slice_new0 (GSourcePrivate);
if (!child_source->priv)
child_source->priv = g_slice_new0 (GSourcePrivate);
source->priv->child_sources = g_slist_prepend (source->priv->child_sources,
g_source_ref (child_source));
child_source->priv->parent_source = source;
g_source_set_priority_unlocked (child_source, context, source->priority);
if (context)
{
UNLOCK_CONTEXT (context);
g_source_attach (child_source, context);
}
}
/**
* g_source_remove_child_source:
* @source:a #GSource
* @child_source: a #GSource previously passed to
* g_source_add_child_source().
*
* Detaches @child_source from @source and destroys it.
**/
void
g_source_remove_child_source (GSource *source,
GSource *child_source)
{
GMainContext *context;
g_return_if_fail (source != NULL);
g_return_if_fail (child_source != NULL);
g_return_if_fail (child_source->priv != NULL && child_source->priv->parent_source == source);
g_return_if_fail (!SOURCE_DESTROYED (source));
g_return_if_fail (!SOURCE_DESTROYED (child_source));
context = source->context;
if (context)
LOCK_CONTEXT (context);
source->priv->child_sources = g_slist_remove (source->priv->child_sources, child_source);
g_source_destroy_internal (child_source, context, TRUE);
g_source_unref_internal (child_source, context, TRUE);
if (context)
UNLOCK_CONTEXT (context);
}
/**
* g_source_set_callback_indirect:
* @source: the source
......@@ -1263,35 +1408,19 @@ g_source_set_funcs (GSource *source,
source->source_funcs = funcs;
}
/**
* g_source_set_priority:
* @source: a #GSource
* @priority: the new priority.
*
* 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.
**/
void
g_source_set_priority (GSource *source,
gint priority)
static void
g_source_set_priority_unlocked (GSource *source,
GMainContext *context,
gint priority)
{
GSList *tmp_list;
GMainContext *context;
g_return_if_fail (source != NULL);
context = source->context;
if (context)
LOCK_CONTEXT (context);
source->priority = priority;
if (context)
{
/* Remove the source from the context's source and then
* add it back so it is sorted in the correct plcae
* add it back so it is sorted in the correct place
*/
g_source_list_remove (source, source->context);
g_source_list_add (source, source->context);
......@@ -1307,9 +1436,44 @@ g_source_set_priority (GSource *source,
tmp_list = tmp_list->next;
}
}
UNLOCK_CONTEXT (source->context);
}
if (source->priv && source->priv->child_sources)
{
tmp_list = source->priv->child_sources;
while (tmp_list)
{
g_source_set_priority_unlocked (tmp_list->data, context, priority);
tmp_list = tmp_list->next;
}
}
}
/**
* g_source_set_priority:
* @source: a #GSource
* @priority: the new priority.
*
* 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.
**/
void
g_source_set_priority (GSource *source,
gint priority)
{
GMainContext *context;
g_return_if_fail (source != NULL);
context = source->context;
if (context)
LOCK_CONTEXT (context);
g_source_set_priority_unlocked (source, context, priority);
if (context)
UNLOCK_CONTEXT (source->context);
}
/**
......@@ -2596,7 +2760,15 @@ g_main_context_prepare (GMainContext *context,
context->in_check_or_prepare--;
if (result)
source->flags |= G_SOURCE_READY;
{
GSource *ready_source = source;
while (ready_source)
{
ready_source->flags |= G_SOURCE_READY;
ready_source = ready_source->priv ? ready_source->priv->parent_source : NULL;
}
}
}
if (source->flags & G_SOURCE_READY)
......@@ -2788,7 +2960,15 @@ g_main_context_check (GMainContext *context,
context->in_check_or_prepare--;
if (result)
source->flags |= G_SOURCE_READY;
{
GSource *ready_source = source;
while (ready_source)
{
ready_source->flags |= G_SOURCE_READY;
ready_source = ready_source->priv ? ready_source->priv->parent_source : NULL;
}
}
}
if (source->flags & G_SOURCE_READY)
......
......@@ -53,6 +53,7 @@ typedef struct _GMainLoop GMainLoop;
* representing an event source.
*/
typedef struct _GSource GSource;
typedef struct _GSourcePrivate GSourcePrivate;
/**
* GSourceCallbackFuncs:
......@@ -157,7 +158,8 @@ struct _GSource
GSource *next;
char *name;
gpointer reserved2;
GSourcePrivate *priv;
};
struct _GSourceCallbackFuncs
......@@ -358,10 +360,15 @@ void g_source_set_callback_indirect (GSource *source,
gpointer callback_data,
GSourceCallbackFuncs *callback_funcs);
void g_source_add_poll (GSource *source,
GPollFD *fd);
void g_source_remove_poll (GSource *source,
GPollFD *fd);
void g_source_add_poll (GSource *source,
GPollFD *fd);
void g_source_remove_poll (GSource *source,
GPollFD *fd);
void g_source_add_child_source (GSource *source,
GSource *child_source);
void g_source_remove_child_source (GSource *source,
GSource *child_source);
#ifndef G_DISABLE_DEPRECATED
void g_source_get_current_time (GSource *source,
......
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