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+/*
+ * 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 security libraries.
+ *
+ * The Initial Developer of the Original Code is Netscape
+ * Communications Corporation. Portions created by Netscape are
+ * Copyright (C) 1994-2000 Netscape Communications Corporation. All
+ * Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the
+ * terms of the GNU General Public License Version 2 or later (the
+ * "GPL"), in which case the provisions of the GPL are applicable
+ * instead of those above. If you wish to allow use of your
+ * version of this file only under the terms of the GPL and not to
+ * allow others to use your version of this file under the MPL,
+ * indicate your decision by deleting the provisions above and
+ * replace them with the notice and other provisions required by
+ * the GPL. If you do not delete the provisions above, a recipient
+ * may use your version of this file under either the MPL or the
+ * GPL.
+ */
+
+/*
+** File: nsrwlock.h
+** Description: API to basic reader-writer lock functions of NSS.
+** These are re-entrant reader writer locks; that is,
+** If I hold the write lock, I can ask for it and get it again.
+** If I hold the write lock, I can also ask for and get a read lock.
+** I can then release the locks in any order (read or write).
+** I must release each lock type as many times as I acquired it.
+** Otherwise, these are normal reader/writer locks.
+**
+** For deadlock detection, locks should be ranked, and no lock may be aquired
+** while I hold a lock of higher rank number.
+** If you don't want that feature, always use NSS_RWLOCK_RANK_NONE.
+** Lock name is for debugging, and is optional (may be NULL)
+**/
+
+#ifndef nssrwlk_h___
+#define nssrwlk_h___
+
+#include "prtypes.h"
+#include "nssrwlkt.h"
+
+#define NSS_RWLOCK_RANK_NONE 0
+
+/* SEC_BEGIN_PROTOS */
+PR_BEGIN_EXTERN_C
+
+/***********************************************************************
+** FUNCTION: NSSRWLock_New
+** DESCRIPTION:
+** Returns a pointer to a newly created reader-writer lock object.
+** INPUTS: Lock rank
+** Lock name
+** OUTPUTS: void
+** RETURN: NSSRWLock*
+** If the lock cannot be created because of resource constraints, NULL
+** is returned.
+**
+***********************************************************************/
+PR_EXTERN(NSSRWLock*) NSSRWLock_New(PRUint32 lock_rank, const char *lock_name);
+
+/***********************************************************************
+** FUNCTION: NSSRWLock_AtomicCreate
+** DESCRIPTION:
+** Given the address of a NULL pointer to a NSSRWLock,
+** atomically initializes that pointer to a newly created NSSRWLock.
+** Returns the value placed into that pointer, or NULL.
+**
+** INPUTS: address of NSRWLock pointer
+** Lock rank
+** Lock name
+** OUTPUTS: NSSRWLock*
+** RETURN: NSSRWLock*
+** If the lock cannot be created because of resource constraints,
+** the pointer will be left NULL.
+**
+***********************************************************************/
+PR_EXTERN(NSSRWLock *)
+nssRWLock_AtomicCreate( NSSRWLock ** prwlock,
+ PRUint32 lock_rank,
+ const char * lock_name);
+
+/***********************************************************************
+** FUNCTION: NSSRWLock_Destroy
+** DESCRIPTION:
+** Destroys a given RW lock object.
+** INPUTS: NSSRWLock *lock - Lock to be freed.
+** OUTPUTS: void
+** RETURN: None
+***********************************************************************/
+PR_EXTERN(void) NSSRWLock_Destroy(NSSRWLock *lock);
+
+/***********************************************************************
+** FUNCTION: NSSRWLock_LockRead
+** DESCRIPTION:
+** Apply a read lock (non-exclusive) on a RWLock
+** INPUTS: NSSRWLock *lock - Lock to be read-locked.
+** OUTPUTS: void
+** RETURN: None
+***********************************************************************/
+PR_EXTERN(void) NSSRWLock_LockRead(NSSRWLock *lock);
+
+/***********************************************************************
+** FUNCTION: NSSRWLock_LockWrite
+** DESCRIPTION:
+** Apply a write lock (exclusive) on a RWLock
+** INPUTS: NSSRWLock *lock - Lock to write-locked.
+** OUTPUTS: void
+** RETURN: None
+***********************************************************************/
+PR_EXTERN(void) NSSRWLock_LockWrite(NSSRWLock *lock);
+
+/***********************************************************************
+** FUNCTION: NSSRWLock_UnlockRead
+** DESCRIPTION:
+** Release a Read lock. Unlocking an unlocked lock has undefined results.
+** INPUTS: NSSRWLock *lock - Lock to unlocked.
+** OUTPUTS: void
+** RETURN: void
+***********************************************************************/
+PR_EXTERN(void) NSSRWLock_UnlockRead(NSSRWLock *lock);
+
+/***********************************************************************
+** FUNCTION: NSSRWLock_UnlockWrite
+** DESCRIPTION:
+** Release a Write lock. Unlocking an unlocked lock has undefined results.
+** INPUTS: NSSRWLock *lock - Lock to unlocked.
+** OUTPUTS: void
+** RETURN: void
+***********************************************************************/
+PR_EXTERN(void) NSSRWLock_UnlockWrite(NSSRWLock *lock);
+
+/***********************************************************************
+** FUNCTION: NSSRWLock_HaveWriteLock
+** DESCRIPTION:
+** Tells caller whether the current thread holds the write lock, or not.
+** INPUTS: NSSRWLock *lock - Lock to test.
+** OUTPUTS: void
+** RETURN: PRBool PR_TRUE IFF the current thread holds the write lock.
+***********************************************************************/
+
+PR_EXTERN(PRBool) NSSRWLock_HaveWriteLock(NSSRWLock *rwlock);
+
+/* SEC_END_PROTOS */
+PR_END_EXTERN_C
+
+#endif /* nsrwlock_h___ */