summaryrefslogtreecommitdiff
path: root/source4/lib/events/events_timed.c
blob: 389c2cbbb7c7dd4349b93260a3f7853a34ee1955 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
/* 
   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#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,
						   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_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;
}

/*
  do a single event loop using the events defined in ev

  return the delay untill the next timed event,
  or zero if a timed event was triggered
*/
struct timeval common_event_loop_timer_delay(struct event_context *ev)
{
	struct timeval current_time = timeval_zero();
	struct timed_event *te = ev->timed_events;

	if (!te) {
		/* have a default tick time of 30 seconds. This guarantees
		   that code that uses its own timeout checking will be
		   able to proceeed eventually */
		return timeval_set(30, 0);
	}

	/*
	 * work out the right timeout for the next timed event
	 *
	 * avoid the syscall to gettimeofday() if the timed event should
	 * be triggered directly
	 *
	 * if there's a delay till the next timed event, we're done
	 * with just returning the delay
	 */
	if (!timeval_is_zero(&te->next_event)) {
		struct timeval delay;

		current_time = timeval_current();

		delay = timeval_until(&current_time, &te->next_event);
		if (!timeval_is_zero(&delay)) {
			return delay;
		}
	}

	/*
	 * ok, we have a timed event that we'll process ...
	 */

	/* 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);

	/*
	 * If the timed event was registered for a zero current_time,
	 * then we pass a zero timeval here too! To avoid the
	 * overhead of gettimeofday() calls.
	 *
	 * otherwise we pass the current time
	 */
	te->handler(ev, te, current_time, 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);

	return timeval_zero();
}