OLD | NEW |
| (Empty) |
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 /* | |
36 ** File: pralarm.h | |
37 ** Description: API to periodic alarms. | |
38 ** | |
39 ** | |
40 ** Alarms are defined to invoke some client specified function at | |
41 ** a time in the future. The notification may be a one time event | |
42 ** or repeated at a fixed interval. The interval at which the next | |
43 ** notification takes place may be modified by the client code only | |
44 ** during the respective notification. | |
45 ** | |
46 ** The notification is delivered on a thread that is part of the | |
47 ** alarm context (PRAlarm). The thread will inherit the priority | |
48 ** of the Alarm creator. | |
49 ** | |
50 ** Any number of periodic alarms (PRAlarmID) may be created within | |
51 ** the context of a single alarm (PRAlarm). The notifications will be | |
52 ** scheduled as close to the desired time as possible. | |
53 ** | |
54 ** Repeating periodic notifies are expected to run at a fixed rate. | |
55 ** That rate is expressed as some number of notifies per period where | |
56 ** the period is much larger than a PRIntervalTime (see prinrval.h). | |
57 */ | |
58 | |
59 #if !defined(pralarm_h) | |
60 #define pralarm_h | |
61 | |
62 #include "prtypes.h" | |
63 #include "prinrval.h" | |
64 | |
65 | |
66 PR_BEGIN_EXTERN_C | |
67 | |
68 /**********************************************************************/ | |
69 /************************* TYPES AND CONSTANTS ************************/ | |
70 /**********************************************************************/ | |
71 | |
72 typedef struct PRAlarm PRAlarm; | |
73 typedef struct PRAlarmID PRAlarmID; | |
74 | |
75 typedef PRBool (PR_CALLBACK *PRPeriodicAlarmFn)( | |
76 PRAlarmID *id, void *clientData, PRUint32 late); | |
77 | |
78 /**********************************************************************/ | |
79 /****************************** FUNCTIONS *****************************/ | |
80 /**********************************************************************/ | |
81 | |
82 /*********************************************************************** | |
83 ** FUNCTION: PR_CreateAlarm | |
84 ** DESCRIPTION: | |
85 ** Create an alarm context. | |
86 ** INPUTS: void | |
87 ** OUTPUTS: None | |
88 ** RETURN: PRAlarm* | |
89 ** | |
90 ** SIDE EFFECTS: | |
91 ** This creates an alarm context, which is an object used for subsequent | |
92 ** notification creations. It also creates a thread that will be used to | |
93 ** deliver the notifications that are expected to be defined. The client | |
94 ** is resposible for destroying the context when appropriate. | |
95 ** RESTRICTIONS: | |
96 ** None. | |
97 ** MEMORY: The object (PRAlarm) and a thread to support notifications. | |
98 ** ALGORITHM: N/A | |
99 ***********************************************************************/ | |
100 NSPR_API(PRAlarm*) PR_CreateAlarm(void); | |
101 | |
102 /*********************************************************************** | |
103 ** FUNCTION: PR_DestroyAlarm | |
104 ** DESCRIPTION: | |
105 ** Destroys the context created by PR_CreateAlarm(). | |
106 ** INPUTS: PRAlarm* | |
107 ** OUTPUTS: None | |
108 ** RETURN: PRStatus | |
109 ** | |
110 ** SIDE EFFECTS: | |
111 ** This destroys the context that was created by PR_CreateAlarm(). | |
112 ** If there are any active alarms (PRAlarmID), they will be cancelled. | |
113 ** Once that is done, the thread that was used to deliver the alarms | |
114 ** will be joined. | |
115 ** RESTRICTIONS: | |
116 ** None. | |
117 ** MEMORY: N/A | |
118 ** ALGORITHM: N/A | |
119 ***********************************************************************/ | |
120 NSPR_API(PRStatus) PR_DestroyAlarm(PRAlarm *alarm); | |
121 | |
122 /*********************************************************************** | |
123 ** FUNCTION: PR_SetAlarm | |
124 ** DESCRIPTION: | |
125 ** Creates a periodic notifier that is to be delivered to a specified | |
126 ** function at some fixed interval. | |
127 ** INPUTS: PRAlarm *alarm Parent alarm context | |
128 ** PRIntervalTime period Interval over which the notifies | |
129 ** are delivered. | |
130 ** PRUint32 rate The rate within the interval that | |
131 ** the notifies will be delivered. | |
132 ** PRPeriodicAlarmFn function Entry point where the notifies | |
133 ** will be delivered. | |
134 ** OUTPUTS: None | |
135 ** RETURN: PRAlarmID* Handle to the notifier just created | |
136 ** or NULL if the request failed. | |
137 ** | |
138 ** SIDE EFFECTS: | |
139 ** A periodic notifier is created. The notifications will be delivered | |
140 ** by the alarm's internal thread at a fixed interval whose rate is the | |
141 ** number of interrupts per interval specified. The first notification | |
142 ** will be delivered as soon as possible, and they will continue until | |
143 ** the notifier routine indicates that they should cease of the alarm | |
144 ** context is destroyed (PR_DestroyAlarm). | |
145 ** RESTRICTIONS: | |
146 ** None. | |
147 ** MEMORY: Memory for the notifier object. | |
148 ** ALGORITHM: The rate at which notifications are delivered are stated | |
149 ** to be "'rate' notifies per 'interval'". The exact time of | |
150 ** the notification is computed based on a epoch established | |
151 ** when the notifier was set. Each notification is delivered | |
152 ** not ealier than the epoch plus the fixed rate times the | |
153 ** notification sequence number. Such notifications have the | |
154 ** potential to be late by not more than 'interval'/'rate'. | |
155 ** The amount of lateness of one notification is taken into | |
156 ** account on the next in an attempt to avoid long term slew. | |
157 ***********************************************************************/ | |
158 NSPR_API(PRAlarmID*) PR_SetAlarm( | |
159 PRAlarm *alarm, PRIntervalTime period, PRUint32 rate, | |
160 PRPeriodicAlarmFn function, void *clientData); | |
161 | |
162 /*********************************************************************** | |
163 ** FUNCTION: PR_ResetAlarm | |
164 ** DESCRIPTION: | |
165 ** Resets an existing alarm. | |
166 ** INPUTS: PRAlarmID *id Identify of the notifier. | |
167 ** PRIntervalTime period Interval over which the notifies | |
168 ** are delivered. | |
169 ** PRUint32 rate The rate within the interval that | |
170 ** the notifies will be delivered. | |
171 ** OUTPUTS: None | |
172 ** RETURN: PRStatus Indication of completion. | |
173 ** | |
174 ** SIDE EFFECTS: | |
175 ** An existing alarm may have its period and rate redefined. The | |
176 ** additional side effect is that the notifier's epoch is recomputed. | |
177 ** The first notification delivered by the newly refreshed alarm is | |
178 ** defined to be 'interval'/'rate' from the time of the reset. | |
179 ** RESTRICTIONS: | |
180 ** This function may only be called in the notifier for that alarm. | |
181 ** MEMORY: N/A. | |
182 ** ALGORITHM: See PR_SetAlarm(). | |
183 ***********************************************************************/ | |
184 NSPR_API(PRStatus) PR_ResetAlarm( | |
185 PRAlarmID *id, PRIntervalTime period, PRUint32 rate); | |
186 | |
187 PR_END_EXTERN_C | |
188 | |
189 #endif /* !defined(pralarm_h) */ | |
190 | |
191 /* prinrval.h */ | |
OLD | NEW |