[glib] gsource: Add support for file descriptors on UNIX
- From: Ryan Lortie <ryanl src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [glib] gsource: Add support for file descriptors on UNIX
- Date: Tue, 15 Jan 2013 19:09:39 +0000 (UTC)
commit cbf68cb22d9f17721654283e97c2320025f03bc7
Author: Ryan Lortie <desrt desrt ca>
Date: Mon Jan 14 16:53:06 2013 -0500
gsource: Add support for file descriptors on UNIX
Adding file descriptors to a GSource provides similar functionality to
the old g_source_add_poll() API with two main differences.
First: the list of handles is managed internally and therefore users are
prevented from randomly modifying the ->events field. This prepares us
for an epoll future where changing the event mask is a syscall.
Second: keeping the list internally allows us to check the ->revents for
events for ourselves, allowing the source to skip implementing
check/prepare. This also prepares us for the future by allowing an
implementation that doesn't need to iterate over all of the sources
every time.
https://bugzilla.gnome.org/show_bug.cgi?id=686853
docs/reference/glib/glib-sections.txt | 4 +
glib/glib.symbols | 4 +
glib/gmain.c | 225 ++++++++++++++++++++++++++++++++-
glib/gmain.h | 17 +++
4 files changed, 246 insertions(+), 4 deletions(-)
---
diff --git a/docs/reference/glib/glib-sections.txt b/docs/reference/glib/glib-sections.txt
index e851942..d5a70b2 100644
--- a/docs/reference/glib/glib-sections.txt
+++ b/docs/reference/glib/glib-sections.txt
@@ -530,6 +530,10 @@ GSourceFunc
g_source_set_callback_indirect
g_source_set_ready_time
g_source_get_ready_time
+g_source_add_unix_fd
+g_source_remove_unix_fd
+g_source_modify_unix_fd
+g_source_query_unix_fd
g_source_add_poll
g_source_remove_poll
g_source_add_child_source
diff --git a/glib/glib.symbols b/glib/glib.symbols
index b8f39b0..b317e7c 100644
--- a/glib/glib.symbols
+++ b/glib/glib.symbols
@@ -628,6 +628,7 @@ g_main_loop_ref
g_main_loop_run
g_main_loop_unref
g_source_add_child_source
+g_source_add_unix_fd
g_source_add_poll
g_source_attach
g_source_destroy
@@ -639,12 +640,15 @@ g_source_get_id
g_source_get_name
g_source_get_priority
g_source_get_ready_time
+g_source_modify_unix_fd
g_source_new
+g_source_query_unix_fd
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_unix_fd
g_source_remove_poll
g_source_set_callback
g_source_set_callback_indirect
diff --git a/glib/gmain.c b/glib/gmain.c
index f1a4592..5807efd 100644
--- a/glib/gmain.c
+++ b/glib/gmain.c
@@ -318,6 +318,11 @@ struct _GSourcePrivate
GSource *parent_source;
gint64 ready_time;
+
+ /* This is currently only used on UNIX, but we always declare it (and
+ * let it remain empty on Windows) to avoid #ifdef all over the place.
+ */
+ GSList *fds;
};
typedef struct _GSourceIter
@@ -1116,6 +1121,9 @@ g_source_attach_unlocked (GSource *source,
tmp_list = tmp_list->next;
}
+ for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
+ g_main_context_add_poll_unlocked (context, source->priority, tmp_list->data);
+
tmp_list = source->priv->child_sources;
while (tmp_list)
{
@@ -1201,6 +1209,9 @@ g_source_destroy_internal (GSource *source,
g_main_context_remove_poll_unlocked (context, tmp_list->data);
tmp_list = tmp_list->next;
}
+
+ for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
+ g_main_context_remove_poll_unlocked (context, tmp_list->data);
}
while (source->priv->child_sources)
@@ -1295,12 +1306,16 @@ g_source_get_context (GSource *source)
* @source:a #GSource
* @fd: a #GPollFD structure holding information about a file
* descriptor to watch.
- *
+ *
* Adds a file descriptor to the set of file descriptors polled for
* this source. This is usually combined with g_source_new() to add an
* event source. The event source's check function will typically test
* the @revents field in the #GPollFD struct and return %TRUE if events need
* to be processed.
+ *
+ * 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.
**/
void
g_source_add_poll (GSource *source,
@@ -1640,6 +1655,12 @@ g_source_set_priority_unlocked (GSource *source,
tmp_list = tmp_list->next;
}
+
+ for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
+ {
+ g_main_context_remove_poll_unlocked (context, tmp_list->data);
+ g_main_context_add_poll_unlocked (context, priority, tmp_list->data);
+ }
}
}
@@ -1969,6 +1990,8 @@ g_source_unref_internal (GSource *source,
g_slist_free (source->poll_fds);
source->poll_fds = NULL;
+ g_slist_free_full (source->priv->fds, g_free);
+
g_slice_free (GSourcePrivate, source->priv);
source->priv = NULL;
@@ -2222,6 +2245,174 @@ g_source_remove_by_funcs_user_data (GSourceFuncs *funcs,
return FALSE;
}
+#ifdef G_OS_UNIX
+/**
+ * g_source_add_unix_fd:
+ * @source: a #GSource
+ * @fd: the fd to monitor
+ * @events: an event mask
+ *
+ * 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 g_source_remove_unix_fd() or
+ * g_source_modify_unix_fd().
+ *
+ * It is not necessary to remove the fd before destroying the source; it
+ * will be cleaned up automatically.
+ *
+ * As the name suggests, this function is not available on Windows.
+ *
+ * Returns: an opaque tag
+ *
+ * Since: 2.36
+ **/
+gpointer
+g_source_add_unix_fd (GSource *source,
+ gint fd,
+ GIOCondition events)
+{
+ GMainContext *context;
+ GPollFD *poll_fd;
+
+ g_return_val_if_fail (source != NULL, NULL);
+ g_return_val_if_fail (!SOURCE_DESTROYED (source), NULL);
+
+ poll_fd = g_new (GPollFD, 1);
+ poll_fd->fd = fd;
+ poll_fd->events = events;
+ poll_fd->revents = 0;
+
+ context = source->context;
+
+ if (context)
+ LOCK_CONTEXT (context);
+
+ source->priv->fds = g_slist_prepend (source->priv->fds, poll_fd);
+
+ if (context)
+ {
+ if (!SOURCE_BLOCKED (source))
+ g_main_context_add_poll_unlocked (context, source->priority, poll_fd);
+ UNLOCK_CONTEXT (context);
+ }
+
+ return poll_fd;
+}
+
+/**
+ * g_source_modify_unix_fd:
+ * @source: a #GSource
+ * @tag: the tag from g_source_add_unix_fd()
+ * @new_events: the new event mask to watch
+ *
+ * Updates the event mask to watch for the fd identified by @tag.
+ *
+ * @tag is the tag returned from g_source_add_unix_fd().
+ *
+ * If you want to remove a fd, don't set its event mask to zero.
+ * Instead, call g_source_remove_unix_fd().
+ *
+ * As the name suggests, this function is not available on Windows.
+ *
+ * Since: 2.36
+ **/
+void
+g_source_modify_unix_fd (GSource *source,
+ gpointer tag,
+ GIOCondition new_events)
+{
+ GMainContext *context;
+ GPollFD *poll_fd;
+
+ g_return_if_fail (source != NULL);
+ g_return_if_fail (g_slist_find (source->priv->fds, tag));
+
+ context = source->context;
+ poll_fd = tag;
+
+ poll_fd->events = new_events;
+
+ if (context)
+ g_main_context_wakeup (context);
+}
+
+/**
+ * g_source_remove_unix_fd:
+ * @source: a #GSource
+ * @tag: the tag from g_source_add_unix_fd()
+ *
+ * Reverses the effect of a previous call to g_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.
+ *
+ * As the name suggests, this function is not available on Windows.
+ *
+ * Since: 2.36
+ **/
+void
+g_source_remove_unix_fd (GSource *source,
+ gpointer tag)
+{
+ GMainContext *context;
+ GPollFD *poll_fd;
+
+ g_return_if_fail (source != NULL);
+ g_return_if_fail (g_slist_find (source->priv->fds, tag));
+
+ context = source->context;
+ poll_fd = tag;
+
+ if (context)
+ LOCK_CONTEXT (context);
+
+ source->priv->fds = g_slist_remove (source->priv->fds, poll_fd);
+
+ if (context)
+ {
+ if (!SOURCE_BLOCKED (source))
+ g_main_context_remove_poll_unlocked (context, poll_fd);
+
+ UNLOCK_CONTEXT (context);
+ }
+
+ g_free (poll_fd);
+}
+
+/**
+ * g_source_query_unix_fd:
+ * @source: a #GSource
+ * @tag: the tag from g_source_add_unix_fd()
+ *
+ * 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.
+ *
+ * As the name suggests, this function is not available on Windows.
+ *
+ * Returns: the conditions reported on the fd
+ *
+ * Since: 2.36
+ **/
+GIOCondition
+g_source_query_unix_fd (GSource *source,
+ gpointer tag)
+{
+ GPollFD *poll_fd;
+
+ g_return_val_if_fail (source != NULL, 0);
+ g_return_val_if_fail (g_slist_find (source->priv->fds, tag), 0);
+
+ poll_fd = tag;
+
+ return poll_fd->revents;
+}
+#endif /* G_OS_UNIX */
+
/**
* g_get_current_time:
* @result: #GTimeVal structure in which to store current time.
@@ -2747,6 +2938,9 @@ block_source (GSource *source)
tmp_list = tmp_list->next;
}
+ for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
+ g_main_context_remove_poll_unlocked (source->context, tmp_list->data);
+
if (source->priv && source->priv->child_sources)
{
tmp_list = source->priv->child_sources;
@@ -2763,7 +2957,7 @@ static void
unblock_source (GSource *source)
{
GSList *tmp_list;
-
+
g_return_if_fail (SOURCE_BLOCKED (source)); /* Source already unblocked */
g_return_if_fail (!SOURCE_DESTROYED (source));
@@ -2776,6 +2970,9 @@ unblock_source (GSource *source)
tmp_list = tmp_list->next;
}
+ for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
+ g_main_context_add_poll_unlocked (source->context, source->priority, tmp_list->data);
+
if (source->priv && source->priv->child_sources)
{
tmp_list = source->priv->child_sources;
@@ -3347,6 +3544,26 @@ g_main_context_check (GMainContext *context,
else
result = FALSE;
+ if (result == FALSE)
+ {
+ GSList *tmp_list;
+
+ /* If not already explicitly flagged ready by ->check()
+ * (or if we have no check) then we can still be ready if
+ * any of our fds poll as ready.
+ */
+ for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
+ {
+ GPollFD *pollfd = tmp_list->data;
+
+ if (pollfd->revents)
+ {
+ result = TRUE;
+ break;
+ }
+ }
+ }
+
if (result == FALSE && source->priv->ready_time != -1)
{
if (!context->time_is_fresh)
@@ -3835,10 +4052,10 @@ g_main_context_poll (GMainContext *context,
* @priority: the priority for this file descriptor which should be
* the same as the priority used for g_source_attach() to ensure that the
* file descriptor is polled whenever the results may be needed.
- *
+ *
* Adds a file descriptor to the set of file descriptors polled for
* this context. This will very seldom be used directly. Instead
- * a typical event source will use g_source_add_poll() instead.
+ * a typical event source will use g_source_add_unix_fd() instead.
**/
void
g_main_context_add_poll (GMainContext *context,
diff --git a/glib/gmain.h b/glib/gmain.h
index e8d64f4..47b4ecf 100644
--- a/glib/gmain.h
+++ b/glib/gmain.h
@@ -470,6 +470,23 @@ void g_source_set_ready_time (GSource *source,
GLIB_AVAILABLE_IN_2_36
gint64 g_source_get_ready_time (GSource *source);
+#ifdef G_OS_UNIX
+GLIB_AVAILABLE_IN_2_36
+gpointer g_source_add_unix_fd (GSource *source,
+ gint fd,
+ GIOCondition events);
+GLIB_AVAILABLE_IN_2_36
+void g_source_modify_unix_fd (GSource *source,
+ gpointer tag,
+ GIOCondition new_events);
+GLIB_AVAILABLE_IN_2_36
+void g_source_remove_unix_fd (GSource *source,
+ gpointer tag);
+GLIB_AVAILABLE_IN_2_36
+GIOCondition g_source_query_unix_fd (GSource *source,
+ gpointer tag);
+#endif
+
/* Used to implement g_source_connect_closure and internally*/
GLIB_AVAILABLE_IN_ALL
void g_source_set_callback_indirect (GSource *source,
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