LCOV - code coverage report
Current view: directory - nsprpub/pr/src/misc - pralarm.c (source / functions) Found Hit Coverage
Test: app.info Lines: 103 0 0.0 %
Date: 2012-06-02 Functions: 7 0 0.0 %

       1                 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2                 : /* ***** BEGIN LICENSE BLOCK *****
       3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       4                 :  *
       5                 :  * The contents of this file are subject to the Mozilla Public License Version
       6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       7                 :  * the License. You may obtain a copy of the License at
       8                 :  * http://www.mozilla.org/MPL/
       9                 :  *
      10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      12                 :  * for the specific language governing rights and limitations under the
      13                 :  * License.
      14                 :  *
      15                 :  * The Original Code is the Netscape Portable Runtime (NSPR).
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is
      18                 :  * Netscape Communications Corporation.
      19                 :  * Portions created by the Initial Developer are Copyright (C) 1998-2000
      20                 :  * the Initial Developer. All Rights Reserved.
      21                 :  *
      22                 :  * Contributor(s):
      23                 :  *
      24                 :  * Alternatively, the contents of this file may be used under the terms of
      25                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      26                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      27                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      28                 :  * of those above. If you wish to allow use of your version of this file only
      29                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      30                 :  * use your version of this file under the terms of the MPL, indicate your
      31                 :  * decision by deleting the provisions above and replace them with the notice
      32                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      33                 :  * the provisions above, a recipient may use your version of this file under
      34                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      35                 :  *
      36                 :  * ***** END LICENSE BLOCK ***** */
      37                 : 
      38                 : #include "primpl.h"
      39                 : 
      40                 : /**********************************************************************/
      41                 : /******************************* PRALARM ******************************/
      42                 : /**********************************************************************/
      43                 : 
      44                 : #include "obsolete/pralarm.h"
      45                 : 
      46                 : struct PRAlarmID {                       /* typedef'd in pralarm.h       */
      47                 :     PRCList list;                        /* circular list linkage        */
      48                 :     PRAlarm *alarm;                      /* back pointer to owning alarm */
      49                 :     PRPeriodicAlarmFn function;          /* function to call for notify  */
      50                 :     void *clientData;                    /* opaque client context        */
      51                 :     PRIntervalTime period;               /* the client defined period    */
      52                 :     PRUint32 rate;                       /* rate of notification         */
      53                 : 
      54                 :     PRUint32 accumulator;                /* keeps track of # notifies    */
      55                 :     PRIntervalTime epoch;                /* when timer was started       */
      56                 :     PRIntervalTime nextNotify;           /* when we'll next do our thing */
      57                 :     PRIntervalTime lastNotify;           /* when we last did our thing   */
      58                 : };
      59                 : 
      60                 : typedef enum {alarm_active, alarm_inactive} _AlarmState;
      61                 : 
      62                 : struct PRAlarm {                         /* typedef'd in pralarm.h       */
      63                 :     PRCList timers;                      /* base of alarm ids list       */
      64                 :     PRLock *lock;                        /* lock used to protect data    */
      65                 :     PRCondVar *cond;                     /* condition that used to wait  */
      66                 :     PRThread *notifier;                  /* thread to deliver notifies   */
      67                 :     PRAlarmID *current;                  /* current alarm being served   */
      68                 :     _AlarmState state;                   /* used to delete the alarm     */
      69                 : };
      70                 : 
      71               0 : static PRAlarmID *pr_getNextAlarm(PRAlarm *alarm, PRAlarmID *id)
      72                 : {
      73                 : /*
      74                 :  * Puts 'id' back into the sorted list iff it's not NULL.
      75                 :  * Removes the first element from the list and returns it (or NULL).
      76                 :  * List is "assumed" to be short.
      77                 :  *
      78                 :  * NB: Caller is providing locking
      79                 :  */
      80                 :     PRCList *timer;
      81               0 :     PRAlarmID *result = id;
      82               0 :     PRIntervalTime now = PR_IntervalNow();
      83                 : 
      84               0 :     if (!PR_CLIST_IS_EMPTY(&alarm->timers))
      85                 :     {    
      86               0 :         if (id != NULL)  /* have to put this id back in */
      87                 :         {        
      88               0 :             PRIntervalTime idDelta = now - id->nextNotify;
      89               0 :             timer = alarm->timers.next;
      90                 :             do
      91                 :             {
      92               0 :                 result = (PRAlarmID*)timer;
      93               0 :                 if ((PRIntervalTime)(now - result->nextNotify) > idDelta)
      94                 :                 {
      95               0 :                     PR_INSERT_BEFORE(&id->list, &alarm->timers);
      96               0 :                     break;
      97                 :                 }
      98               0 :                 timer = timer->next;
      99               0 :             } while (timer != &alarm->timers);
     100                 :         }
     101               0 :         result = (PRAlarmID*)(timer = PR_LIST_HEAD(&alarm->timers));
     102               0 :         PR_REMOVE_LINK(timer);  /* remove it from the list */
     103                 :     }
     104                 : 
     105               0 :     return result;
     106                 : }  /* pr_getNextAlarm */
     107                 : 
     108               0 : static PRIntervalTime pr_PredictNextNotifyTime(PRAlarmID *id)
     109                 : {
     110                 :     PRIntervalTime delta;
     111               0 :     PRFloat64 baseRate = (PRFloat64)id->period / (PRFloat64)id->rate;
     112               0 :     PRFloat64 offsetFromEpoch = (PRFloat64)id->accumulator * baseRate;
     113                 : 
     114               0 :     id->accumulator += 1;  /* every call advances to next period */
     115               0 :     id->lastNotify = id->nextNotify;  /* just keeping track of things */
     116               0 :     id->nextNotify = (PRIntervalTime)(offsetFromEpoch + 0.5);
     117                 : 
     118               0 :     delta = id->nextNotify - id->lastNotify;
     119               0 :     return delta;
     120                 : }  /* pr_PredictNextNotifyTime */
     121                 : 
     122               0 : static void PR_CALLBACK pr_alarmNotifier(void *arg)
     123                 : {
     124                 :     /*
     125                 :      * This is the root of the notifier thread. There is one such thread
     126                 :      * for each PRAlarm. It may service an arbitrary (though assumed to be
     127                 :      * small) number of alarms using the same thread and structure. It
     128                 :      * continues to run until the alarm is destroyed.
     129                 :      */
     130               0 :     PRAlarmID *id = NULL;
     131               0 :     PRAlarm *alarm = (PRAlarm*)arg;
     132               0 :     enum {notify, abort, scan} why = scan;
     133                 : 
     134               0 :     while (why != abort)
     135                 :     {
     136                 :         PRIntervalTime pause;
     137                 : 
     138               0 :         PR_Lock(alarm->lock);
     139               0 :         while (why == scan)
     140                 :         {
     141               0 :             alarm->current = NULL;  /* reset current id */
     142               0 :             if (alarm->state == alarm_inactive) why = abort;  /* we're toast */
     143               0 :             else if (why == scan)  /* the dominant case */
     144                 :             {
     145               0 :                 id = pr_getNextAlarm(alarm, id);  /* even if it's the same */
     146               0 :                 if (id == NULL)  /* there are no alarms set */
     147               0 :                     (void)PR_WaitCondVar(alarm->cond, PR_INTERVAL_NO_TIMEOUT);
     148                 :                 else
     149                 :                 {
     150               0 :                     pause = id->nextNotify - (PR_IntervalNow() - id->epoch);
     151               0 :                     if ((PRInt32)pause <= 0)  /* is this one's time up? */
     152                 :                     {
     153               0 :                         why = notify;  /* set up to do our thing */
     154               0 :                         alarm->current = id;  /* id we're about to schedule */
     155                 :                     }
     156                 :                     else
     157               0 :                         (void)PR_WaitCondVar(alarm->cond, pause);  /* dally */
     158                 :                 }
     159                 :             }
     160                 :         }
     161               0 :         PR_Unlock(alarm->lock);
     162                 : 
     163               0 :         if (why == notify)
     164                 :         {
     165               0 :             (void)pr_PredictNextNotifyTime(id);
     166               0 :             if (!id->function(id, id->clientData, ~pause))
     167                 :             {
     168                 :                 /*
     169                 :                  * Notified function decided not to continue. Free
     170                 :                  * the alarm id to make sure it doesn't get back on
     171                 :                  * the list.
     172                 :                  */
     173               0 :                 PR_DELETE(id);  /* free notifier object */
     174               0 :                 id = NULL;  /* so it doesn't get back into the list */
     175                 :             }
     176               0 :             why = scan;  /* so we can cycle through the loop again */
     177                 :         }
     178                 :     }
     179                 : 
     180               0 : }  /* pr_alarm_notifier */
     181                 : 
     182               0 : PR_IMPLEMENT(PRAlarm*) PR_CreateAlarm(void)
     183                 : {
     184               0 :     PRAlarm *alarm = PR_NEWZAP(PRAlarm);
     185               0 :     if (alarm != NULL)
     186                 :     {
     187               0 :         if ((alarm->lock = PR_NewLock()) == NULL) goto done;
     188               0 :         if ((alarm->cond = PR_NewCondVar(alarm->lock)) == NULL) goto done;
     189               0 :         alarm->state = alarm_active;
     190               0 :         PR_INIT_CLIST(&alarm->timers);
     191               0 :         alarm->notifier = PR_CreateThread(
     192                 :             PR_USER_THREAD, pr_alarmNotifier, alarm,
     193               0 :             PR_GetThreadPriority(PR_GetCurrentThread()),
     194                 :             PR_LOCAL_THREAD, PR_JOINABLE_THREAD, 0);
     195               0 :         if (alarm->notifier == NULL) goto done;
     196                 :     }
     197               0 :     return alarm;
     198                 : 
     199                 : done:
     200               0 :     if (alarm->cond != NULL) PR_DestroyCondVar(alarm->cond);
     201               0 :     if (alarm->lock != NULL) PR_DestroyLock(alarm->lock);
     202               0 :     PR_DELETE(alarm);
     203               0 :     return NULL;
     204                 : }  /* CreateAlarm */
     205                 : 
     206               0 : PR_IMPLEMENT(PRStatus) PR_DestroyAlarm(PRAlarm *alarm)
     207                 : {
     208                 :     PRStatus rv;
     209                 : 
     210               0 :     PR_Lock(alarm->lock);
     211               0 :     alarm->state = alarm_inactive;
     212               0 :     rv = PR_NotifyCondVar(alarm->cond);
     213               0 :     PR_Unlock(alarm->lock);
     214                 : 
     215               0 :     if (rv == PR_SUCCESS)
     216               0 :         rv = PR_JoinThread(alarm->notifier);
     217               0 :     if (rv == PR_SUCCESS)
     218                 :     {
     219               0 :         PR_DestroyCondVar(alarm->cond);
     220               0 :         PR_DestroyLock(alarm->lock);
     221               0 :         PR_DELETE(alarm);
     222                 :     }
     223               0 :     return rv;
     224                 : }  /* PR_DestroyAlarm */
     225                 : 
     226               0 : PR_IMPLEMENT(PRAlarmID*) PR_SetAlarm(
     227                 :     PRAlarm *alarm, PRIntervalTime period, PRUint32 rate,
     228                 :     PRPeriodicAlarmFn function, void *clientData)
     229                 : {
     230                 :     /*
     231                 :      * Create a new periodic alarm an existing current structure.
     232                 :      * Set up the context and compute the first notify time (immediate).
     233                 :      * Link the new ID into the head of the list (since it's notifying
     234                 :      * immediately).
     235                 :      */
     236                 : 
     237               0 :     PRAlarmID *id = PR_NEWZAP(PRAlarmID);
     238                 : 
     239               0 :     if (!id)
     240               0 :         return NULL;
     241                 : 
     242               0 :     id->alarm = alarm;
     243               0 :     PR_INIT_CLIST(&id->list);
     244               0 :     id->function = function;
     245               0 :     id->clientData = clientData;
     246               0 :     id->period = period;
     247               0 :     id->rate = rate;
     248               0 :     id->epoch = id->nextNotify = PR_IntervalNow();
     249               0 :     (void)pr_PredictNextNotifyTime(id);
     250                 : 
     251               0 :     PR_Lock(alarm->lock);
     252               0 :     PR_INSERT_BEFORE(&id->list, &alarm->timers);
     253               0 :     PR_NotifyCondVar(alarm->cond);
     254               0 :     PR_Unlock(alarm->lock);
     255                 : 
     256               0 :     return id;
     257                 : }  /* PR_SetAlarm */
     258                 : 
     259               0 : PR_IMPLEMENT(PRStatus) PR_ResetAlarm(
     260                 :     PRAlarmID *id, PRIntervalTime period, PRUint32 rate)
     261                 : {
     262                 :     /*
     263                 :      * Can only be called from within the notify routine. Doesn't
     264                 :      * need locking because it can only be called from within the
     265                 :      * notify routine.
     266                 :      */
     267               0 :     if (id != id->alarm->current)
     268               0 :         return PR_FAILURE;
     269               0 :     id->period = period;
     270               0 :     id->rate = rate;
     271               0 :     id->accumulator = 1;
     272               0 :     id->epoch = PR_IntervalNow();
     273               0 :     (void)pr_PredictNextNotifyTime(id);
     274               0 :     return PR_SUCCESS;
     275                 : }  /* PR_ResetAlarm */
     276                 : 
     277                 : 
     278                 : 

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