tevent: add tevent_queue infrastructure

metze

lib/tevent/libtevent.m4

@@ -27,7 +27,7 @@ AC_SUBST(TEVENT_LIBS)
 TEVENT_CFLAGS="-I$teventdir"
 
 TEVENT_OBJ="tevent.o tevent_fd.o tevent_timed.o tevent_signal.o tevent_debug.o tevent_util.o"
-TEVENT_OBJ="$TEVENT_OBJ tevent_req.o tevent_wakeup.o"
+TEVENT_OBJ="$TEVENT_OBJ tevent_req.o tevent_wakeup.o tevent_queue.o"
 TEVENT_OBJ="$TEVENT_OBJ tevent_standard.o tevent_select.o"
 
 AC_CHECK_HEADERS(sys/epoll.h)

lib/tevent/tevent.h

@@ -338,6 +338,28 @@ struct timeval tevent_timeval_add(const struct timeval *tv, uint32_t secs,
 
 struct timeval tevent_timeval_current_ofs(uint32_t secs, uint32_t usecs);
 
+struct tevent_queue;
+
+struct tevent_queue *_tevent_queue_create(TALLOC_CTX *mem_ctx,
+					  const char *name,
+					  const char *location);
+
+#define tevent_queue_create(_mem_ctx, _name) \
+	_tevent_queue_create((_mem_ctx), (_name), __location__)
+
+typedef void (*tevent_queue_trigger_fn_t)(struct tevent_req *req,
+					  void *private_data);
+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);
+bool tevent_queue_start(struct tevent_queue *queue,
+			struct tevent_context *ev);
+void tevent_queue_stop(struct tevent_queue *queue);
+
+size_t tevent_queue_length(struct tevent_queue *queue);
+
 #ifdef TEVENT_COMPAT_DEFINES
 
 #define event_context	tevent_context

lib/tevent/tevent_queue.c

@@ -0,0 +1,198 @@
+/*
+   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;
+
+	tevent_queue_trigger_fn_t trigger;
+	void *private_data;
+};
+
+struct tevent_queue {
+	const char *name;
+	const char *location;
+
+	bool running;
+	struct tevent_timer *timer;
+
+	size_t length;
+	struct tevent_queue_entry *list;
+};
+
+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 (e->triggered &&
+	    q->running &&
+	    q->list) {
+		q->list->triggered = true;
+		q->list->trigger(q->list->req,
+				 q->list->private_data);
+	}
+
+	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->location = location;
+
+	/* queue is running by default */
+	queue->running = true;
+
+	talloc_set_destructor(queue, tevent_queue_destructor);
+	return queue;
+}
+
+static void tevent_queue_timer_start(struct tevent_context *ev,
+				     struct tevent_timer *te,
+				     struct timeval now,
+				     void *private_data)
+{
+	struct tevent_queue *q = talloc_get_type(private_data,
+				  struct tevent_queue);
+
+	talloc_free(te);
+	q->timer = NULL;
+
+	q->list->triggered = true;
+	q->list->trigger(q->list->req, q->list->private_data);
+}
+
+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 = talloc_zero(req, struct tevent_queue_entry);
+	if (e == NULL) {
+		return false;
+	}
+
+	e->queue = queue;
+	e->req = req;
+	e->trigger = trigger;
+	e->private_data = private_data;
+
+	if (queue->running &&
+	    !queue->timer &&
+	    !queue->list) {
+		queue->timer = tevent_add_timer(ev, queue, tevent_timeval_zero(),
+						tevent_queue_timer_start,
+						queue);
+		if (!queue->timer) {
+			talloc_free(e);
+			return false;
+		}
+	}
+
+	DLIST_ADD_END(queue->list, e, struct tevent_queue_entry *);
+	queue->length++;
+	talloc_set_destructor(e, tevent_queue_entry_destructor);
+
+	return true;
+}
+
+bool tevent_queue_start(struct tevent_queue *queue,
+			struct tevent_context *ev)
+{
+	if (queue->running) {
+		/* already started */
+		return true;
+	}
+
+	if (!queue->timer &&
+	    queue->list) {
+		queue->timer = tevent_add_timer(ev, queue, tevent_timeval_zero(),
+						tevent_queue_timer_start,
+						queue);
+		if (!queue->timer) {
+			return false;
+		}
+	}
+
+	queue->running = true;
+
+	return true;
+}
+
+void tevent_queue_stop(struct tevent_queue *queue)
+{
+	queue->running = false;
+	talloc_free(queue->timer);
+	queue->timer = NULL;
+}
+
+size_t tevent_queue_length(struct tevent_queue *queue)
+{
+	return queue->length;
+}