tevent: add support for immediate events

They're like directly triggered timed events,
but you can preallocated them and scheduling them
will not fail.

metze

1 files changed, 139 insertions, 0 deletions

diff --git a/lib/tevent/tevent_immediate.c b/lib/tevent/tevent_immediate.c
new file mode 100644
index 0000000000..1ac293e175
--- /dev/null
+++ b/lib/tevent/tevent_immediate.c
@@ -0,0 +1,139 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   common events code for immediate events
+
+   Copyright (C) Stefan Metzmacher 2009
+
+     ** NOTE! The following LGPL license applies to the tevent
+     ** library. This does NOT imply that all of Samba is released
+     ** under the LGPL
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "replace.h"
+#include "tevent.h"
+#include "tevent_internal.h"
+#include "tevent_util.h"
+
+static void tevent_common_immediate_cancel(struct tevent_immediate *im)
+{
+	if (!im->event_ctx) {
+		return;
+	}
+
+	tevent_debug(im->event_ctx, TEVENT_DEBUG_TRACE,
+		     "Cancel immediate event %p \"%s\"\n",
+		     im, im->handler_name);
+
+	/* let the backend free im->additional_data */
+	if (im->cancel_fn) {
+		im->cancel_fn(im);
+	}
+
+	DLIST_REMOVE(im->event_ctx->immediate_events, im);
+	im->event_ctx		= NULL;
+	im->handler		= NULL;
+	im->private_data	= NULL;
+	im->handler_name	= NULL;
+	im->schedule_location	= NULL;
+	im->cancel_fn		= NULL;
+	im->additional_data	= NULL;
+
+	talloc_set_destructor(im, NULL);
+}
+
+/*
+  destroy an immediate event
+*/
+static int tevent_common_immediate_destructor(struct tevent_immediate *im)
+{
+	tevent_common_immediate_cancel(im);
+	return 0;
+}
+
+/*
+ * schedule an immediate event on
+ */
+void tevent_common_schedule_immediate(struct tevent_immediate *im,
+				      struct tevent_context *ev,
+				      tevent_immediate_handler_t handler,
+				      void *private_data,
+				      const char *handler_name,
+				      const char *location)
+{
+	tevent_common_immediate_cancel(im);
+
+	if (!handler) {
+		return;
+	}
+
+	im->event_ctx		= ev;
+	im->handler		= handler;
+	im->private_data	= private_data;
+	im->handler_name	= handler_name;
+	im->schedule_location	= location;
+	im->cancel_fn		= NULL;
+	im->additional_data	= NULL;
+
+	DLIST_ADD_END(ev->immediate_events, im, struct tevent_immediate *);
+	talloc_set_destructor(im, tevent_common_immediate_destructor);
+
+	tevent_debug(ev, TEVENT_DEBUG_TRACE,
+		     "Schedule immediate event \"%s\": %p\n",
+		     handler_name, im);
+}
+
+/*
+  trigger the first immediate event and return true
+  if no event was triggered return false
+*/
+bool tevent_common_loop_immediate(struct tevent_context *ev)
+{
+	struct tevent_immediate *im = ev->immediate_events;
+	tevent_immediate_handler_t handler;
+	void *private_data;
+
+	if (!im) {
+		return false;
+	}
+
+	tevent_debug(ev, TEVENT_DEBUG_TRACE,
+		     "Run immediate event \"%s\": %p\n",
+		     im->handler_name, im);
+
+	/*
+	 * remember the handler and then clear the event
+	 * the handler might reschedule the event
+	 */
+	handler = im->handler;
+	private_data = im->private_data;
+
+	DLIST_REMOVE(im->event_ctx->immediate_events, im);
+	im->event_ctx		= NULL;
+	im->handler		= NULL;
+	im->private_data	= NULL;
+	im->handler_name	= NULL;
+	im->schedule_location	= NULL;
+	im->cancel_fn		= NULL;
+	im->additional_data	= NULL;
+
+	talloc_set_destructor(im, NULL);
+
+	handler(ev, im, private_data);
+
+	return true;
+}
+