r20539: - split the common timer related events code into events_timed.c

- make it easier to plug in a new events backend

- add simpler 'select' and 'epoll' backends

This is part of the effort to add good AIO support. The events_aio.c
backend is done, but sometimes dies with a SEGV, which is why it isn't
enabled yet.
(This used to be commit 934f18283dbc7958944931a93a854526bcd54884)

1 files changed, 136 insertions, 0 deletions

diff --git a/source4/lib/events/events_timed.c b/source4/lib/events/events_timed.c
new file mode 100644
index 0000000000..6b0919d0f1
--- /dev/null
+++ b/source4/lib/events/events_timed.c
@@ -0,0 +1,136 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   common events code for timed events
+
+   Copyright (C) Andrew Tridgell	2003-2006
+   Copyright (C) Stefan Metzmacher	2005
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program 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 General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "system/select.h"
+#include "lib/util/dlinklist.h"
+#include "lib/events/events.h"
+#include "lib/events/events_internal.h"
+
+/*
+  destroy a timed event
+*/
+static int common_event_timed_destructor(struct timed_event *te)
+{
+	struct event_context *ev = talloc_get_type(te->event_ctx->additional_data,
+							   struct event_context);
+	DLIST_REMOVE(ev->timed_events, te);
+	return 0;
+}
+
+static int common_event_timed_deny_destructor(struct timed_event *te)
+{
+	return -1;
+}
+
+/*
+  add a timed event
+  return NULL on failure (memory allocation error)
+*/
+struct timed_event *common_event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ctx,
+					   struct timeval next_event, 
+					   event_timed_handler_t handler, 
+					   void *private_data) 
+{
+	struct timed_event *te, *last_te, *cur_te;
+
+	te = talloc(mem_ctx?mem_ctx:ev, struct timed_event);
+	if (te == NULL) return NULL;
+
+	te->event_ctx		= ev;
+	te->next_event		= next_event;
+	te->handler		= handler;
+	te->private_data	= private_data;
+	te->additional_data	= NULL;
+
+	/* keep the list ordered */
+	last_te = NULL;
+	for (cur_te = ev->timed_events; cur_te; cur_te = cur_te->next) {
+		/* if the new event comes before the current one break */
+		if (!timeval_is_zero(&cur_te->next_event) &&
+		    timeval_compare(&te->next_event,
+				    &cur_te->next_event) < 0) {
+			break;
+		}
+
+		last_te = cur_te;
+	}
+
+	DLIST_ADD_AFTER(ev->timed_events, te, last_te);
+
+	talloc_set_destructor(te, common_event_timed_destructor);
+
+	return te;
+}
+
+/*
+  a timer has gone off - call it
+*/
+void common_event_loop_timer(struct event_context *ev)
+{
+	struct timeval t = timeval_current();
+	struct timed_event *te = ev->timed_events;
+
+	if (te == NULL) {
+		return;
+	}
+
+	/* deny the handler to free the event */
+	talloc_set_destructor(te, common_event_timed_deny_destructor);
+
+	/* We need to remove the timer from the list before calling the
+	 * handler because in a semi-async inner event loop called from the
+	 * handler we don't want to come across this event again -- vl */
+	DLIST_REMOVE(ev->timed_events, te);
+
+	te->handler(ev, te, t, te->private_data);
+
+	/* The destructor isn't necessary anymore, we've already removed the
+	 * event from the list. */
+	talloc_set_destructor(te, NULL);
+
+	talloc_free(te);
+}
+
+/*
+  do a single event loop using the events defined in ev 
+*/
+struct timeval common_event_loop_delay(struct event_context *ev)
+{
+	struct timeval tval;
+
+	/* work out the right timeout for all timed events */
+	if (ev->timed_events) {
+		struct timeval t = timeval_current();
+		tval = timeval_until(&t, &ev->timed_events->next_event);
+	} else {
+		/* have a default tick time of 30 seconds. This guarantees
+		   that code that uses its own timeout checking will be
+		   able to proceeed eventually */
+		tval = timeval_set(30, 0);
+	}
+	
+	return tval;
+}
+