OSX/libsecurity_asn1/lib/prmon.h

   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
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  10  * implied. See the License for the specific language governing
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  12  *
  13  * The Original Code is the Netscape Portable Runtime (NSPR).
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  15  * The Initial Developer of the Original Code is Netscape
  16  * Communications Corporation.  Portions created by Netscape are
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  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
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  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
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  34
  35 #ifndef prmon_h___
  36 #define prmon_h___
  37
  38 #include <security_asn1/prtypes.h>
  39 #include <security_asn1/prinrval.h>
  40
  41 PR_BEGIN_EXTERN_C
  42
  43 typedef 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 */
  52 NSPR_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 */
  60 NSPR_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 */
  67 NSPR_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 */
  74 NSPR_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 */
  92 NSPR_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 */
  99 NSPR_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 */
 106 NSPR_API(PRStatus) PR_NotifyAll(PRMonitor *mon);
 107
 108 PR_END_EXTERN_C
 109
 110 #endif /* prmon_h___ */