Initial commit of upstream NSPR (4.7.3) and NSS3 (3.12).

third_party/nspr/mozilla/nsprpub/pr/src/bthreads/btcvar.c

Index: third_party/nspr/mozilla/nsprpub/pr/src/bthreads/btcvar.c
diff --git a/third_party/nspr/mozilla/nsprpub/pr/src/bthreads/btcvar.c b/third_party/nspr/mozilla/nsprpub/pr/src/bthreads/btcvar.c
new file mode 100644
index 0000000000000000000000000000000000000000..f615bf5b3a836aa161f66005eccbc1cf5969bed4
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+++ b/third_party/nspr/mozilla/nsprpub/pr/src/bthreads/btcvar.c
@@ -0,0 +1,276 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the Netscape Portable Runtime (NSPR).
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1998-2000
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include <kernel/OS.h>
+
+#include "primpl.h"
+
+/*
+** Create a new condition variable.
+**
+** 	"lock" is the lock used to protect the condition variable.
+**
+** Condition variables are synchronization objects that threads can use
+** to wait for some condition to occur.
+**
+** This may fail if memory is tight or if some operating system resource
+** is low. In such cases, a NULL will be returned.
+*/
+PR_IMPLEMENT(PRCondVar*)
+    PR_NewCondVar (PRLock *lock)
+{
+    PRCondVar *cv = PR_NEW( PRCondVar );
+    PR_ASSERT( NULL != lock );
+    if( NULL != cv )
+    {
+	cv->lock = lock;
+	cv->sem = create_sem(0, "CVSem");
+	cv->handshakeSem = create_sem(0, "CVHandshake");
+	cv->signalSem = create_sem( 0, "CVSignal");
+	cv->signalBenCount = 0;
+	cv->ns = cv->nw = 0;
+	PR_ASSERT( cv->sem >= B_NO_ERROR );
+	PR_ASSERT( cv->handshakeSem >= B_NO_ERROR );
+	PR_ASSERT( cv->signalSem >= B_NO_ERROR );
+    }
+    return cv;
+} /* PR_NewCondVar */
+
+/*
+** Destroy a condition variable. There must be no thread
+** waiting on the condvar. The caller is responsible for guaranteeing
+** that the condvar is no longer in use.
+**
+*/
+PR_IMPLEMENT(void)
+    PR_DestroyCondVar (PRCondVar *cvar)
+{
+    status_t result = delete_sem( cvar->sem );
+    PR_ASSERT( result == B_NO_ERROR );
+    
+    result = delete_sem( cvar->handshakeSem );
+    PR_ASSERT( result == B_NO_ERROR );
+
+    result = delete_sem( cvar->signalSem );
+    PR_ASSERT( result == B_NO_ERROR );
+
+    PR_DELETE( cvar );
+}
+
+/*
+** The thread that waits on a condition is blocked in a "waiting on
+** condition" state until another thread notifies the condition or a
+** caller specified amount of time expires. The lock associated with
+** the condition variable will be released, which must have be held
+** prior to the call to wait.
+**
+** Logically a notified thread is moved from the "waiting on condition"
+** state and made "ready." When scheduled, it will attempt to reacquire
+** the lock that it held when wait was called.
+**
+** The timeout has two well known values, PR_INTERVAL_NO_TIMEOUT and
+** PR_INTERVAL_NO_WAIT. The former value requires that a condition be
+** notified (or the thread interrupted) before it will resume from the
+** wait. If the timeout has a value of PR_INTERVAL_NO_WAIT, the effect
+** is to release the lock, possibly causing a rescheduling within the
+** runtime, then immediately attempting to reacquire the lock and resume.
+**
+** Any other value for timeout will cause the thread to be rescheduled
+** either due to explicit notification or an expired interval. The latter
+** must be determined by treating time as one part of the monitored data
+** being protected by the lock and tested explicitly for an expired
+** interval.
+**
+** Returns PR_FAILURE if the caller has not locked the lock associated
+** with the condition variable or the thread was interrupted (PR_Interrupt()).
+** The particular reason can be extracted with PR_GetError().
+*/
+PR_IMPLEMENT(PRStatus)
+    PR_WaitCondVar (PRCondVar *cvar, PRIntervalTime timeout)
+{
+    status_t err;
+    if( timeout == PR_INTERVAL_NO_WAIT ) 
+    {
+        PR_Unlock( cvar->lock );
+        PR_Lock( cvar->lock );
+        return PR_SUCCESS;
+    }
+
+    if( atomic_add( &cvar->signalBenCount, 1 ) > 0 ) 
+    {
+        if (acquire_sem(cvar->signalSem) == B_INTERRUPTED) 
+        {
+            atomic_add( &cvar->signalBenCount, -1 );
+            return PR_FAILURE;
+        }
+    }
+    cvar->nw += 1;
+    if( atomic_add( &cvar->signalBenCount, -1 ) > 1 ) 
+    {
+        release_sem_etc(cvar->signalSem, 1, B_DO_NOT_RESCHEDULE);
+    }
+
+    PR_Unlock( cvar->lock );
+    if( timeout==PR_INTERVAL_NO_TIMEOUT ) 
+    {
+    	err = acquire_sem(cvar->sem);
+    } 
+    else 
+    {
+    	err = acquire_sem_etc(cvar->sem, 1, B_RELATIVE_TIMEOUT, PR_IntervalToMicroseconds(timeout) );
+    }
+
+    if( atomic_add( &cvar->signalBenCount, 1 ) > 0 ) 
+    {
+        while (acquire_sem(cvar->signalSem) == B_INTERRUPTED);
+    }
+
+    if (cvar->ns > 0)
+    {
+        release_sem_etc(cvar->handshakeSem, 1, B_DO_NOT_RESCHEDULE);
+        cvar->ns -= 1;
+    }
+    cvar->nw -= 1;
+    if( atomic_add( &cvar->signalBenCount, -1 ) > 1 ) 
+    {
+        release_sem_etc(cvar->signalSem, 1, B_DO_NOT_RESCHEDULE);
+    }
+
+    PR_Lock( cvar->lock );
+    if(err!=B_NO_ERROR) 
+    {
+        return PR_FAILURE;
+    }
+    return PR_SUCCESS;
+}
+
+/*
+** Notify ONE thread that is currently waiting on 'cvar'. Which thread is
+** dependent on the implementation of the runtime. Common sense would dictate
+** that all threads waiting on a single condition have identical semantics,
+** therefore which one gets notified is not significant. 
+**
+** The calling thead must hold the lock that protects the condition, as
+** well as the invariants that are tightly bound to the condition, when
+** notify is called.
+**
+** Returns PR_FAILURE if the caller has not locked the lock associated
+** with the condition variable.
+*/
+PR_IMPLEMENT(PRStatus)
+    PR_NotifyCondVar (PRCondVar *cvar)
+{
+    status_t err ;
+    if( atomic_add( &cvar->signalBenCount, 1 ) > 0 ) 
+    {
+        if (acquire_sem(cvar->signalSem) == B_INTERRUPTED) 
+        {
+            atomic_add( &cvar->signalBenCount, -1 );
+            return PR_FAILURE;
+        }
+    }
+    if (cvar->nw > cvar->ns)
+    {
+        cvar->ns += 1;
+        release_sem_etc(cvar->sem, 1, B_DO_NOT_RESCHEDULE);
+        if( atomic_add( &cvar->signalBenCount, -1 ) > 1 ) 
+        {
+            release_sem_etc(cvar->signalSem, 1, B_DO_NOT_RESCHEDULE);
+        }
+
+        while (acquire_sem(cvar->handshakeSem) == B_INTERRUPTED) 
+        {
+            err = B_INTERRUPTED; 
+        }
+    }
+    else
+    {
+        if( atomic_add( &cvar->signalBenCount, -1 ) > 1 )
+        {
+            release_sem_etc(cvar->signalSem, 1, B_DO_NOT_RESCHEDULE);
+        }
+    }
+    return PR_SUCCESS; 
+}
+
+/*
+** Notify all of the threads waiting on the condition variable. The order
+** that the threads are notified is indeterminant. The lock that protects
+** the condition must be held.
+**
+** Returns PR_FAILURE if the caller has not locked the lock associated
+** with the condition variable.
+*/
+PR_IMPLEMENT(PRStatus)
+    PR_NotifyAllCondVar (PRCondVar *cvar)
+{
+    int32 handshakes;
+    status_t err = B_OK;
+
+    if( atomic_add( &cvar->signalBenCount, 1 ) > 0 ) 
+    {
+        if (acquire_sem(cvar->signalSem) == B_INTERRUPTED) 
+        {
+            atomic_add( &cvar->signalBenCount, -1 );
+            return PR_FAILURE;
+        }
+    }
+
+    if (cvar->nw > cvar->ns)
+    {
+        handshakes = cvar->nw - cvar->ns;
+        cvar->ns = cvar->nw;				
+        release_sem_etc(cvar->sem, handshakes, B_DO_NOT_RESCHEDULE);	
+        if( atomic_add( &cvar->signalBenCount, -1 ) > 1 ) 
+        {
+            release_sem_etc(cvar->signalSem, 1, B_DO_NOT_RESCHEDULE);
+        }
+
+        while (acquire_sem_etc(cvar->handshakeSem, handshakes, 0, 0) == B_INTERRUPTED) 
+        {
+            err = B_INTERRUPTED; 
+        }
+    }
+    else
+    {
+        if( atomic_add( &cvar->signalBenCount, -1 ) > 1 ) 
+        {
+            release_sem_etc(cvar->signalSem, 1, B_DO_NOT_RESCHEDULE);
+        }
+    }
+    return PR_SUCCESS;
+}