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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /nsprpub/pr/src/threads/prsem.c
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'nsprpub/pr/src/threads/prsem.c')
-rw-r--r--nsprpub/pr/src/threads/prsem.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/nsprpub/pr/src/threads/prsem.c b/nsprpub/pr/src/threads/prsem.c
new file mode 100644
index 000000000..f5f261fe9
--- /dev/null
+++ b/nsprpub/pr/src/threads/prsem.c
@@ -0,0 +1,138 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "primpl.h"
+#include "obsolete/prsem.h"
+
+/************************************************************************/
+
+/*
+** Create a new semaphore.
+*/
+PR_IMPLEMENT(PRSemaphore*) PR_NewSem(PRUintn value)
+{
+ PRSemaphore *sem;
+ PRCondVar *cvar;
+ PRLock *lock;
+
+ sem = PR_NEWZAP(PRSemaphore);
+ if (sem) {
+#ifdef HAVE_CVAR_BUILT_ON_SEM
+ _PR_MD_NEW_SEM(&sem->md, value);
+#else
+ lock = PR_NewLock();
+ if (!lock) {
+ PR_DELETE(sem);
+ return NULL;
+ }
+
+ cvar = PR_NewCondVar(lock);
+ if (!cvar) {
+ PR_DestroyLock(lock);
+ PR_DELETE(sem);
+ return NULL;
+ }
+ sem->cvar = cvar;
+ sem->count = value;
+#endif
+ }
+ return sem;
+}
+
+/*
+** Destroy a semaphore. There must be no thread waiting on the semaphore.
+** The caller is responsible for guaranteeing that the semaphore is
+** no longer in use.
+*/
+PR_IMPLEMENT(void) PR_DestroySem(PRSemaphore *sem)
+{
+#ifdef HAVE_CVAR_BUILT_ON_SEM
+ _PR_MD_DESTROY_SEM(&sem->md);
+#else
+ PR_ASSERT(sem->waiters == 0);
+
+ PR_DestroyLock(sem->cvar->lock);
+ PR_DestroyCondVar(sem->cvar);
+#endif
+ PR_DELETE(sem);
+}
+
+/*
+** Wait on a Semaphore.
+**
+** This routine allows a calling thread to wait or proceed depending upon the
+** state of the semahore sem. The thread can proceed only if the counter value
+** of the semaphore sem is currently greater than 0. If the value of semaphore
+** sem is positive, it is decremented by one and the routine returns immediately
+** allowing the calling thread to continue. If the value of semaphore sem is 0,
+** the calling thread blocks awaiting the semaphore to be released by another
+** thread.
+**
+** This routine can return PR_PENDING_INTERRUPT if the waiting thread
+** has been interrupted.
+*/
+PR_IMPLEMENT(PRStatus) PR_WaitSem(PRSemaphore *sem)
+{
+ PRStatus status = PR_SUCCESS;
+
+#ifdef HAVE_CVAR_BUILT_ON_SEM
+ return _PR_MD_WAIT_SEM(&sem->md);
+#else
+ PR_Lock(sem->cvar->lock);
+ while (sem->count == 0) {
+ sem->waiters++;
+ status = PR_WaitCondVar(sem->cvar, PR_INTERVAL_NO_TIMEOUT);
+ sem->waiters--;
+ if (status != PR_SUCCESS)
+ break;
+ }
+ if (status == PR_SUCCESS)
+ sem->count--;
+ PR_Unlock(sem->cvar->lock);
+#endif
+
+ return (status);
+}
+
+/*
+** This routine increments the counter value of the semaphore. If other threads
+** are blocked for the semaphore, then the scheduler will determine which ONE
+** thread will be unblocked.
+*/
+PR_IMPLEMENT(void) PR_PostSem(PRSemaphore *sem)
+{
+#ifdef HAVE_CVAR_BUILT_ON_SEM
+ _PR_MD_POST_SEM(&sem->md);
+#else
+ PR_Lock(sem->cvar->lock);
+ if (sem->waiters)
+ PR_NotifyCondVar(sem->cvar);
+ sem->count++;
+ PR_Unlock(sem->cvar->lock);
+#endif
+}
+
+#if DEBUG
+/*
+** Returns the value of the semaphore referenced by sem without affecting
+** the state of the semaphore. The value represents the semaphore vaule
+** at the time of the call, but may not be the actual value when the
+** caller inspects it. (FOR DEBUGGING ONLY)
+*/
+PR_IMPLEMENT(PRUintn) PR_GetValueSem(PRSemaphore *sem)
+{
+ PRUintn rv;
+
+#ifdef HAVE_CVAR_BUILT_ON_SEM
+ rv = _PR_MD_GET_VALUE_SEM(&sem->md);
+#else
+ PR_Lock(sem->cvar->lock);
+ rv = sem->count;
+ PR_Unlock(sem->cvar->lock);
+#endif
+
+ return rv;
+}
+#endif