1 files changed, 300 insertions, 0 deletions
diff --git a/ctdb/lib/tevent/tevent_queue.c b/ctdb/lib/tevent/tevent_queue.c
new file mode 100644
index 0000000000..4750675802
--- /dev/null
+++ b/ctdb/lib/tevent/tevent_queue.c
@@ -0,0 +1,300 @@
+/*
+   Unix SMB/CIFS implementation.
+   Infrastructure for async requests
+   Copyright (C) Volker Lendecke 2008
+   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"
+
+struct tevent_queue_entry {
+	struct tevent_queue_entry *prev, *next;
+	struct tevent_queue *queue;
+
+	bool triggered;
+
+	struct tevent_req *req;
+	struct tevent_context *ev;
+
+	tevent_queue_trigger_fn_t trigger;
+	void *private_data;
+};
+
+struct tevent_queue {
+	const char *name;
+	const char *location;
+
+	bool running;
+	struct tevent_immediate *immediate;
+
+	size_t length;
+	struct tevent_queue_entry *list;
+};
+
+static void tevent_queue_immediate_trigger(struct tevent_context *ev,
+					   struct tevent_immediate *im,
+					   void *private_data);
+
+static int tevent_queue_entry_destructor(struct tevent_queue_entry *e)
+{
+	struct tevent_queue *q = e->queue;
+
+	if (!q) {
+		return 0;
+	}
+
+	DLIST_REMOVE(q->list, e);
+	q->length--;
+
+	if (!q->running) {
+		return 0;
+	}
+
+	if (!q->list) {
+		return 0;
+	}
+
+	if (q->list->triggered) {
+		return 0;
+	}
+
+	tevent_schedule_immediate(q->immediate,
+				  q->list->ev,
+				  tevent_queue_immediate_trigger,
+				  q);
+
+	return 0;
+}
+
+static int tevent_queue_destructor(struct tevent_queue *q)
+{
+	q->running = false;
+
+	while (q->list) {
+		struct tevent_queue_entry *e = q->list;
+		talloc_free(e);
+	}
+
+	return 0;
+}
+
+struct tevent_queue *_tevent_queue_create(TALLOC_CTX *mem_ctx,
+					  const char *name,
+					  const char *location)
+{
+	struct tevent_queue *queue;
+
+	queue = talloc_zero(mem_ctx, struct tevent_queue);
+	if (!queue) {
+		return NULL;
+	}
+
+	queue->name = talloc_strdup(queue, name);
+	if (!queue->name) {
+		talloc_free(queue);
+		return NULL;
+	}
+	queue->immediate = tevent_create_immediate(queue);
+	if (!queue->immediate) {
+		talloc_free(queue);
+		return NULL;
+	}
+
+	queue->location = location;
+
+	/* queue is running by default */
+	queue->running = true;
+
+	talloc_set_destructor(queue, tevent_queue_destructor);
+	return queue;
+}
+
+static void tevent_queue_immediate_trigger(struct tevent_context *ev,
+					   struct tevent_immediate *im,
+					   void *private_data)
+{
+	struct tevent_queue *q = talloc_get_type(private_data,
+				  struct tevent_queue);
+
+	if (!q->running) {
+		return;
+	}
+
+	q->list->triggered = true;
+	q->list->trigger(q->list->req, q->list->private_data);
+}
+
+static struct tevent_queue_entry *tevent_queue_add_internal(
+					struct tevent_queue *queue,
+					struct tevent_context *ev,
+					struct tevent_req *req,
+					tevent_queue_trigger_fn_t trigger,
+					void *private_data,
+					bool allow_direct)
+{
+	struct tevent_queue_entry *e;
+
+	e = talloc_zero(req, struct tevent_queue_entry);
+	if (e == NULL) {
+		return NULL;
+	}
+
+	e->queue = queue;
+	e->req = req;
+	e->ev = ev;
+	e->trigger = trigger;
+	e->private_data = private_data;
+
+	/*
+	 * if there is no trigger, it is just a blocker
+	 */
+	if (trigger == NULL) {
+		e->triggered = true;
+	}
+
+	if (queue->length > 0) {
+		/*
+		 * if there are already entries in the
+		 * queue do not optimize.
+		 */
+		allow_direct = false;
+	}
+
+	if (req->async.fn != NULL) {
+		/*
+		 * If the callers wants to optimize for the
+		 * empty queue case, call the trigger only
+		 * if there is no callback defined for the
+		 * request yet.
+		 */
+		allow_direct = false;
+	}
+
+	DLIST_ADD_END(queue->list, e, struct tevent_queue_entry *);
+	queue->length++;
+	talloc_set_destructor(e, tevent_queue_entry_destructor);
+
+	if (!queue->running) {
+		return e;
+	}
+
+	if (queue->list->triggered) {
+		return e;
+	}
+
+	/*
+	 * If allowed we directly call the trigger
+	 * avoiding possible delays caused by
+	 * an immediate event.
+	 */
+	if (allow_direct) {
+		queue->list->triggered = true;
+		queue->list->trigger(queue->list->req,
+				     queue->list->private_data);
+		return e;
+	}
+
+	tevent_schedule_immediate(queue->immediate,
+				  queue->list->ev,
+				  tevent_queue_immediate_trigger,
+				  queue);
+
+	return e;
+}
+
+bool tevent_queue_add(struct tevent_queue *queue,
+		      struct tevent_context *ev,
+		      struct tevent_req *req,
+		      tevent_queue_trigger_fn_t trigger,
+		      void *private_data)
+{
+	struct tevent_queue_entry *e;
+
+	e = tevent_queue_add_internal(queue, ev, req,
+				      trigger, private_data, false);
+	if (e == NULL) {
+		return false;
+	}
+
+	return true;
+}
+
+struct tevent_queue_entry *tevent_queue_add_entry(
+					struct tevent_queue *queue,
+					struct tevent_context *ev,
+					struct tevent_req *req,
+					tevent_queue_trigger_fn_t trigger,
+					void *private_data)
+{
+	return tevent_queue_add_internal(queue, ev, req,
+					 trigger, private_data, false);
+}
+
+struct tevent_queue_entry *tevent_queue_add_optimize_empty(
+					struct tevent_queue *queue,
+					struct tevent_context *ev,
+					struct tevent_req *req,
+					tevent_queue_trigger_fn_t trigger,
+					void *private_data)
+{
+	return tevent_queue_add_internal(queue, ev, req,
+					 trigger, private_data, true);
+}
+
+void tevent_queue_start(struct tevent_queue *queue)
+{
+	if (queue->running) {
+		/* already started */
+		return;
+	}
+
+	queue->running = true;
+
+	if (!queue->list) {
+		return;
+	}
+
+	if (queue->list->triggered) {
+		return;
+	}
+
+	tevent_schedule_immediate(queue->immediate,
+				  queue->list->ev,
+				  tevent_queue_immediate_trigger,
+				  queue);
+}
+
+void tevent_queue_stop(struct tevent_queue *queue)
+{
+	queue->running = false;
+}
+
+size_t tevent_queue_length(struct tevent_queue *queue)
+{
+	return queue->length;
+}
+
+bool tevent_queue_running(struct tevent_queue *queue)
+{
+	return queue->running;
+}