1/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2/*
3 * The contents of this file are subject to the Mozilla Public
4 * License Version 1.1 (the "License"); you may not use this file
5 * except in compliance with the License. You may obtain a copy of
6 * the License at http://www.mozilla.org/MPL/
7 *
8 * Software distributed under the License is distributed on an "AS
9 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
10 * implied. See the License for the specific language governing
11 * rights and limitations under the License.
12 *
13 * The Original Code is the Netscape Portable Runtime (NSPR).
14 *
15 * The Initial Developer of the Original Code is Netscape
16 * Communications Corporation.  Portions created by Netscape are
17 * Copyright (C) 1998-2000 Netscape Communications Corporation.  All
18 * Rights Reserved.
19 *
20 * Contributor(s):
21 *
22 * Alternatively, the contents of this file may be used under the
23 * terms of the GNU General Public License Version 2 or later (the
24 * "GPL"), in which case the provisions of the GPL are applicable
25 * instead of those above.  If you wish to allow use of your
26 * version of this file only under the terms of the GPL and not to
27 * allow others to use your version of this file under the MPL,
28 * indicate your decision by deleting the provisions above and
29 * replace them with the notice and other provisions required by
30 * the GPL.  If you do not delete the provisions above, a recipient
31 * may use your version of this file under either the MPL or the
32 * GPL.
33 */
34
35#ifndef prmon_h___
36#define prmon_h___
37
38#include <security_asn1/prtypes.h>
39#include <security_asn1/prinrval.h>
40
41PR_BEGIN_EXTERN_C
42
43typedef struct PRMonitor PRMonitor;
44
45/*
46** Create a new monitor. Monitors are re-entrant locks with a single built-in
47** condition variable.
48**
49** This may fail if memory is tight or if some operating system resource
50** is low.
51*/
52NSPR_API(PRMonitor*) PR_NewMonitor(void);
53
54/*
55** Destroy a monitor. The caller is responsible for guaranteeing that the
56** monitor is no longer in use. There must be no thread waiting on the monitor's
57** condition variable and that the lock is not held.
58**
59*/
60NSPR_API(void) PR_DestroyMonitor(PRMonitor *mon);
61
62/*
63** Enter the lock associated with the monitor. If the calling thread currently
64** is in the monitor, the call to enter will silently succeed. In either case,
65** it will increment the entry count by one.
66*/
67NSPR_API(void) PR_EnterMonitor(PRMonitor *mon);
68
69/*
70** Decrement the entry count associated with the monitor. If the decremented
71** entry count is zero, the monitor is exited. Returns PR_FAILURE if the
72** calling thread has not entered the monitor.
73*/
74NSPR_API(PRStatus) PR_ExitMonitor(PRMonitor *mon);
75
76/*
77** Wait for a notify on the monitor's condition variable. Sleep for "ticks"
78** amount of time (if "ticks" is PR_INTERVAL_NO_TIMEOUT then the sleep is
79** indefinite).
80**
81** While the thread is waiting it exits the monitor (as if it called
82** PR_ExitMonitor as many times as it had called PR_EnterMonitor).  When
83** the wait has finished the thread regains control of the monitors lock
84** with the same entry count as before the wait began.
85**
86** The thread waiting on the monitor will be resumed when the monitor is
87** notified (assuming the thread is the next in line to receive the
88** notify) or when the "ticks" timeout elapses.
89**
90** Returns PR_FAILURE if the caller has not entered the monitor.
91*/
92NSPR_API(PRStatus) PR_Wait(PRMonitor *mon, PRIntervalTime ticks);
93
94/*
95** Notify a thread waiting on the monitor's condition variable. If a thread
96** is waiting on the condition variable (using PR_Wait) then it is awakened
97** and attempts to reenter the monitor.
98*/
99NSPR_API(PRStatus) PR_Notify(PRMonitor *mon);
100
101/*
102** Notify all of the threads waiting on the monitor's condition variable.
103** All of threads waiting on the condition are scheduled to reenter the
104** monitor.
105*/
106NSPR_API(PRStatus) PR_NotifyAll(PRMonitor *mon);
107
108PR_END_EXTERN_C
109
110#endif /* prmon_h___ */
111