nspr-4.8.6/mozilla/nsprpub/pr/src/bthreads/btthread.c - nest-learning-thermostat/5.1.7/nspr - Git at Google

 /* -*- 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 <support/TLS.h>

 #include "prlog.h"
 #include "primpl.h"
 #include "prcvar.h"
 #include "prpdce.h"

 #include <stdlib.h>
 #include <string.h>
 #include <signal.h>

 /* values for PRThread.state */
 #define BT_THREAD_PRIMORD   0x01    /* this is the primordial thread */
 #define BT_THREAD_SYSTEM    0x02    /* this is a system thread */
 #define BT_THREAD_JOINABLE  0x04	/* this is a joinable thread */

 struct _BT_Bookeeping
 {
     PRLock *ml;                 /* a lock to protect ourselves */
 	sem_id cleanUpSem;		/* the primoridal thread will block on this
 							   sem while waiting for the user threads */
     PRInt32 threadCount;	/* user thred count */

 } bt_book = { NULL, B_ERROR, 0 };


 #define BT_TPD_LIMIT 128	/* number of TPD slots we'll provide (arbitrary) */

 /* these will be used to map an index returned by PR_NewThreadPrivateIndex()
    to the corresponding beos native TLS slot number, and to the destructor
    for that slot - note that, because it is allocated globally, this data
    will be automatically zeroed for us when the program begins */
 static int32 tpd_beosTLSSlots[BT_TPD_LIMIT];
 static PRThreadPrivateDTOR tpd_dtors[BT_TPD_LIMIT];

 static vint32 tpd_slotsUsed=0;	/* number of currently-allocated TPD slots */
 static int32 tls_prThreadSlot;	/* TLS slot in which PRThread will be stored */

 /* this mutex will be used to synchronize access to every
    PRThread.md.joinSem and PRThread.md.is_joining (we could
    actually allocate one per thread, but that seems a bit excessive,
    especially considering that there will probably be little
    contention, PR_JoinThread() is allowed to block anyway, and the code
    protected by the mutex is short/fast) */
 static PRLock *joinSemLock;

 static PRUint32 _bt_MapNSPRToNativePriority( PRThreadPriority priority );
 static PRThreadPriority _bt_MapNativeToNSPRPriority( PRUint32 priority );
 static void _bt_CleanupThread(void *arg);
 static PRThread *_bt_AttachThread();

 void
 _PR_InitThreads (PRThreadType type, PRThreadPriority priority,
                  PRUintn maxPTDs)
 {
     PRThread *primordialThread;
     PRUint32  beThreadPriority;

 	/* allocate joinSem mutex */
 	joinSemLock = PR_NewLock();
 	if (joinSemLock == NULL)
 	{
 		PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
 		return;
     }

     /*
     ** Create and initialize NSPR structure for our primordial thread.
     */

     primordialThread = PR_NEWZAP(PRThread);
     if( NULL == primordialThread )
     {
         PR_SetError( PR_OUT_OF_MEMORY_ERROR, 0 );
         return;
     }

 	primordialThread->md.joinSem = B_ERROR;

     /*
     ** Set the priority to the desired level.
     */

     beThreadPriority = _bt_MapNSPRToNativePriority( priority );

     set_thread_priority( find_thread( NULL ), beThreadPriority );

     primordialThread->priority = priority;


 	/* set the thread's state - note that the thread is not joinable */
     primordialThread->state |= BT_THREAD_PRIMORD;
 	if (type == PR_SYSTEM_THREAD)
 		primordialThread->state |= BT_THREAD_SYSTEM;

     /*
     ** Allocate a TLS slot for the PRThread structure (just using
     ** native TLS, as opposed to NSPR TPD, will make PR_GetCurrentThread()
     ** somewhat faster, and will leave one more TPD slot for our client)
     */

 	tls_prThreadSlot = tls_allocate();

     /*
     ** Stuff our new PRThread structure into our thread specific
     ** slot.
     */

 	tls_set(tls_prThreadSlot, primordialThread);

 	/* allocate lock for bt_book */
     bt_book.ml = PR_NewLock();
     if( NULL == bt_book.ml )
     {
     	PR_SetError( PR_OUT_OF_MEMORY_ERROR, 0 );
 	return;
     }
 }

 PRUint32
 _bt_MapNSPRToNativePriority( PRThreadPriority priority )
     {
     switch( priority )
     {
     	case PR_PRIORITY_LOW:	 return( B_LOW_PRIORITY );
 	case PR_PRIORITY_NORMAL: return( B_NORMAL_PRIORITY );
 	case PR_PRIORITY_HIGH:	 return( B_DISPLAY_PRIORITY );
 	case PR_PRIORITY_URGENT: return( B_URGENT_DISPLAY_PRIORITY );
 	default:		 return( B_NORMAL_PRIORITY );
     }
 }

 PRThreadPriority
 _bt_MapNativeToNSPRPriority(PRUint32 priority)
     {
 	if (priority < B_NORMAL_PRIORITY)
 		return PR_PRIORITY_LOW;
 	if (priority < B_DISPLAY_PRIORITY)
 		return PR_PRIORITY_NORMAL;
 	if (priority < B_URGENT_DISPLAY_PRIORITY)
 		return PR_PRIORITY_HIGH;
 	return PR_PRIORITY_URGENT;
 }

 PRUint32
 _bt_mapNativeToNSPRPriority( int32 priority )
 {
     switch( priority )
     {
     	case PR_PRIORITY_LOW:	 return( B_LOW_PRIORITY );
 	case PR_PRIORITY_NORMAL: return( B_NORMAL_PRIORITY );
 	case PR_PRIORITY_HIGH:	 return( B_DISPLAY_PRIORITY );
 	case PR_PRIORITY_URGENT: return( B_URGENT_DISPLAY_PRIORITY );
 	default:		 return( B_NORMAL_PRIORITY );
     }
 }

 /* This method is called by all NSPR threads as they exit */
 void _bt_CleanupThread(void *arg)
 {
 	PRThread *me = PR_GetCurrentThread();
 	int32 i;

 	/* first, clean up all thread-private data */
 	for (i = 0; i < tpd_slotsUsed; i++)
 	{
 		void *oldValue = tls_get(tpd_beosTLSSlots[i]);
 		if ( oldValue != NULL && tpd_dtors[i] != NULL )
 			(*tpd_dtors[i])(oldValue);
 	}

 	/* if this thread is joinable, wait for someone to join it */
 	if (me->state & BT_THREAD_JOINABLE)
 	{
 		/* protect access to our joinSem */
 		PR_Lock(joinSemLock);

 		if (me->md.is_joining)
 		{
 			/* someone is already waiting to join us (they've
 			   allocated a joinSem for us) - let them know we're
 			   ready */
 			delete_sem(me->md.joinSem);

 			PR_Unlock(joinSemLock);

 		}
 		else
     {
 			/* noone is currently waiting for our demise - it
 			   is our responsibility to allocate the joinSem
 			   and block on it */
 			me->md.joinSem = create_sem(0, "join sem");

 			/* we're done accessing our joinSem */
 			PR_Unlock(joinSemLock);

 			/* wait for someone to join us */
 			while (acquire_sem(me->md.joinSem) == B_INTERRUPTED);
 	    }
 	}

 	/* if this is a user thread, we must update our books */
 	if ((me->state & BT_THREAD_SYSTEM) == 0)
 	{
 		/* synchronize access to bt_book */
     PR_Lock( bt_book.ml );

 		/* decrement the number of currently-alive user threads */
 	bt_book.threadCount--;

 		if (bt_book.threadCount == 0 && bt_book.cleanUpSem != B_ERROR) {
 			/* we are the last user thread, and the primordial thread is
 			   blocked in PR_Cleanup() waiting for us to finish - notify
 			   it */
 			delete_sem(bt_book.cleanUpSem);
 	}

     PR_Unlock( bt_book.ml );
 	}

 	/* finally, delete this thread's PRThread */
 	PR_DELETE(me);
 }

 /**
  * This is a wrapper that all threads invoke that allows us to set some
  * things up prior to a thread's invocation and clean up after a thread has
  * exited.
  */
 static void*
 _bt_root (void* arg)
 	{
     PRThread *thred = (PRThread*)arg;
     PRIntn rv;
     void *privData;
     status_t result;
     int i;

 	/* save our PRThread object into our TLS */
 	tls_set(tls_prThreadSlot, thred);

     thred->startFunc(thred->arg);  /* run the dang thing */

 	/* clean up */
 	_bt_CleanupThread(NULL);

 	return 0;
 }

 PR_IMPLEMENT(PRThread*)
     PR_CreateThread (PRThreadType type, void (*start)(void* arg), void* arg,
                      PRThreadPriority priority, PRThreadScope scope,
                      PRThreadState state, PRUint32 stackSize)
 {
     PRUint32 bePriority;

     PRThread* thred;

     if (!_pr_initialized) _PR_ImplicitInitialization();

 	thred = PR_NEWZAP(PRThread);
  	if (thred == NULL)
 	{
         PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
         return NULL;
     }

     thred->md.joinSem = B_ERROR;

         thred->arg = arg;
         thred->startFunc = start;
         thred->priority = priority;

 	if( state == PR_JOINABLE_THREAD )
 	{
 	    thred->state |= BT_THREAD_JOINABLE;
 	}

         /* keep some books */

 	PR_Lock( bt_book.ml );

 	if (type == PR_USER_THREAD)
 	{
 	    bt_book.threadCount++;
         }

 	PR_Unlock( bt_book.ml );

 	bePriority = _bt_MapNSPRToNativePriority( priority );

         thred->md.tid = spawn_thread((thread_func)_bt_root, "moz-thread",
                                      bePriority, thred);
         if (thred->md.tid < B_OK) {
             PR_SetError(PR_UNKNOWN_ERROR, thred->md.tid);
             PR_DELETE(thred);
 			return NULL;
         }

         if (resume_thread(thred->md.tid) < B_OK) {
             PR_SetError(PR_UNKNOWN_ERROR, 0);
             PR_DELETE(thred);
 			return NULL;
         }

     return thred;
     }

 PR_IMPLEMENT(PRThread*)
 	PR_AttachThread(PRThreadType type, PRThreadPriority priority,
 					PRThreadStack *stack)
 {
 	/* PR_GetCurrentThread() will attach a thread if necessary */
 	return PR_GetCurrentThread();
 }

 PR_IMPLEMENT(void)
 	PR_DetachThread()
 {
 	/* we don't support detaching */
 }

 PR_IMPLEMENT(PRStatus)
     PR_JoinThread (PRThread* thred)
 {
     status_t eval, status;

     PR_ASSERT(thred != NULL);

 	if ((thred->state & BT_THREAD_JOINABLE) == 0)
     {
 	PR_SetError( PR_INVALID_ARGUMENT_ERROR, 0 );
 	return( PR_FAILURE );
     }

 	/* synchronize access to the thread's joinSem */
 	PR_Lock(joinSemLock);

 	if (thred->md.is_joining)
 	{
 		/* another thread is already waiting to join the specified
 		   thread - we must fail */
 		PR_Unlock(joinSemLock);
 		return PR_FAILURE;
 	}

 	/* let others know we are waiting to join */
 	thred->md.is_joining = PR_TRUE;

 	if (thred->md.joinSem == B_ERROR)
 	{
 		/* the thread hasn't finished yet - it is our responsibility to
 		   allocate a joinSem and wait on it */
 		thred->md.joinSem = create_sem(0, "join sem");

 		/* we're done changing the joinSem now */
 		PR_Unlock(joinSemLock);

 		/* wait for the thread to finish */
 		while (acquire_sem(thred->md.joinSem) == B_INTERRUPTED);

 	}
 	else
 	{
 		/* the thread has already finished, and has allocated the
 		   joinSem itself - let it know it can finally die */
 		delete_sem(thred->md.joinSem);

 		PR_Unlock(joinSemLock);
     }

 	/* make sure the thread is dead */
     wait_for_thread(thred->md.tid, &eval);

     return PR_SUCCESS;
 }

 PR_IMPLEMENT(PRThread*)
     PR_GetCurrentThread ()
 {
     PRThread* thred;

     if (!_pr_initialized) _PR_ImplicitInitialization();

     thred = (PRThread *)tls_get( tls_prThreadSlot);
 	if (thred == NULL)
 	{
 		/* this thread doesn't have a PRThread structure (it must be
 		   a native thread not created by the NSPR) - assimilate it */
 		thred = _bt_AttachThread();
 	}
     PR_ASSERT(NULL != thred);

     return thred;
 }

 PR_IMPLEMENT(PRThreadScope)
     PR_GetThreadScope (const PRThread* thred)
 {
     PR_ASSERT(thred != NULL);
     return PR_GLOBAL_THREAD;
 }

 PR_IMPLEMENT(PRThreadType)
     PR_GetThreadType (const PRThread* thred)
 {
     PR_ASSERT(thred != NULL);
     return (thred->state & BT_THREAD_SYSTEM) ?
         PR_SYSTEM_THREAD : PR_USER_THREAD;
 }

 PR_IMPLEMENT(PRThreadState)
     PR_GetThreadState (const PRThread* thred)
 {
     PR_ASSERT(thred != NULL);
     return (thred->state & BT_THREAD_JOINABLE)?
     					PR_JOINABLE_THREAD: PR_UNJOINABLE_THREAD;
 }

 PR_IMPLEMENT(PRThreadPriority)
     PR_GetThreadPriority (const PRThread* thred)
 {
     PR_ASSERT(thred != NULL);
     return thred->priority;
 }  /* PR_GetThreadPriority */

 PR_IMPLEMENT(void) PR_SetThreadPriority(PRThread *thred,
                                         PRThreadPriority newPri)
 {
     PRUint32 bePriority;

     PR_ASSERT( thred != NULL );

     thred->priority = newPri;
     bePriority = _bt_MapNSPRToNativePriority( newPri );
     set_thread_priority( thred->md.tid, bePriority );
 }

 PR_IMPLEMENT(PRStatus)
     PR_NewThreadPrivateIndex (PRUintn* newIndex,
                               PRThreadPrivateDTOR destructor)
 {
 	int32    index;

     if (!_pr_initialized) _PR_ImplicitInitialization();

 	/* reserve the next available tpd slot */
 	index = atomic_add( &tpd_slotsUsed, 1 );
 	if (index >= BT_TPD_LIMIT)
 	{
 		/* no slots left - decrement value, then fail */
 		atomic_add( &tpd_slotsUsed, -1 );
 		PR_SetError( PR_TPD_RANGE_ERROR, 0 );
 	    return( PR_FAILURE );
 	}

 	/* allocate a beos-native TLS slot for this index (the new slot
 	   automatically contains NULL) */
 	tpd_beosTLSSlots[index] = tls_allocate();

 	/* remember the destructor */
 	tpd_dtors[index] = destructor;

     *newIndex = (PRUintn)index;

     return( PR_SUCCESS );
 }

 PR_IMPLEMENT(PRStatus)
     PR_SetThreadPrivate (PRUintn index, void* priv)
 {
 	void *oldValue;

     /*
     ** Sanity checking
     */

     if(index < 0 || index >= tpd_slotsUsed || index >= BT_TPD_LIMIT)
     {
 		PR_SetError( PR_TPD_RANGE_ERROR, 0 );
 	return( PR_FAILURE );
     }

 	/* if the old value isn't NULL, and the dtor for this slot isn't
 	   NULL, we must destroy the data */
 	oldValue = tls_get(tpd_beosTLSSlots[index]);
 	if (oldValue != NULL && tpd_dtors[index] != NULL)
 		(*tpd_dtors[index])(oldValue);

 	/* save new value */
 	tls_set(tpd_beosTLSSlots[index], priv);

 	    return( PR_SUCCESS );
 	}

 PR_IMPLEMENT(void*)
     PR_GetThreadPrivate (PRUintn index)
 {
 	/* make sure the index is valid */
 	if (index < 0 || index >= tpd_slotsUsed || index >= BT_TPD_LIMIT)
     {
 		PR_SetError( PR_TPD_RANGE_ERROR, 0 );
 		return NULL;
     }

 	/* return the value */
 	return tls_get( tpd_beosTLSSlots[index] );
 	}


 PR_IMPLEMENT(PRStatus)
     PR_Interrupt (PRThread* thred)
 {
     PRIntn rv;

     PR_ASSERT(thred != NULL);

     /*
     ** there seems to be a bug in beos R5 in which calling
     ** resume_thread() on a blocked thread returns B_OK instead
     ** of B_BAD_THREAD_STATE (beos bug #20000422-19095).  as such,
     ** to interrupt a thread, we will simply suspend then resume it
     ** (no longer call resume_thread(), check for B_BAD_THREAD_STATE,
     ** the suspend/resume to wake up a blocked thread).  this wakes
     ** up blocked threads properly, and doesn't hurt unblocked threads
     ** (they simply get stopped then re-started immediately)
     */

     rv = suspend_thread( thred->md.tid );
     if( rv != B_NO_ERROR )
     {
         /* this doesn't appear to be a valid thread_id */
         PR_SetError( PR_UNKNOWN_ERROR, rv );
         return PR_FAILURE;
     }

     rv = resume_thread( thred->md.tid );
     if( rv != B_NO_ERROR )
     {
         PR_SetError( PR_UNKNOWN_ERROR, rv );
         return PR_FAILURE;
     }

     return PR_SUCCESS;
 }

 PR_IMPLEMENT(void)
     PR_ClearInterrupt ()
 {
 }

 PR_IMPLEMENT(PRStatus)
     PR_Yield ()
 {
     /* we just sleep for long enough to cause a reschedule (100
        microseconds) */
     snooze(100);
 }

 #define BT_MILLION 1000000UL

 PR_IMPLEMENT(PRStatus)
     PR_Sleep (PRIntervalTime ticks)
 {
     bigtime_t tps;
     status_t status;

     if (!_pr_initialized) _PR_ImplicitInitialization();

     tps = PR_IntervalToMicroseconds( ticks );

     status = snooze(tps);
     if (status == B_NO_ERROR) return PR_SUCCESS;

     PR_SetError(PR_NOT_IMPLEMENTED_ERROR, status);
     return PR_FAILURE;
 }

 PR_IMPLEMENT(PRStatus)
     PR_Cleanup ()
 {
     PRThread *me = PR_GetCurrentThread();

     PR_ASSERT(me->state & BT_THREAD_PRIMORD);
     if ((me->state & BT_THREAD_PRIMORD) == 0) {
         return PR_FAILURE;
     }

     PR_Lock( bt_book.ml );

 	if (bt_book.threadCount != 0)
     {
 		/* we'll have to wait for some threads to finish - create a
 		   sem to block on */
 		bt_book.cleanUpSem = create_sem(0, "cleanup sem");
     }

     PR_Unlock( bt_book.ml );

 	/* note that, if all the user threads were already dead, we
 	   wouldn't have created a sem above, so this acquire_sem()
 	   will fail immediately */
 	while (acquire_sem(bt_book.cleanUpSem) == B_INTERRUPTED);

     return PR_SUCCESS;
 }

 PR_IMPLEMENT(void)
     PR_ProcessExit (PRIntn status)
 {
     exit(status);
 }

 PRThread *_bt_AttachThread()
 {
 	PRThread *thread;
 	thread_info tInfo;

 	/* make sure this thread doesn't already have a PRThread structure */
 	PR_ASSERT(tls_get(tls_prThreadSlot) == NULL);

 	/* allocate a PRThread structure for this thread */
 	thread = PR_NEWZAP(PRThread);
 	if (thread == NULL)
 	{
 		PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
 		return NULL;
 	}

 	/* get the native thread's current state */
 	get_thread_info(find_thread(NULL), &tInfo);

 	/* initialize new PRThread */
 	thread->md.tid = tInfo.thread;
 	thread->md.joinSem = B_ERROR;
 	thread->priority = _bt_MapNativeToNSPRPriority(tInfo.priority);

 	/* attached threads are always non-joinable user threads */
 	thread->state = 0;

 	/* increment user thread count */
 	PR_Lock(bt_book.ml);
 	bt_book.threadCount++;
 	PR_Unlock(bt_book.ml);

 	/* store this thread's PRThread */
 	tls_set(tls_prThreadSlot, thread);

 	/* the thread must call _bt_CleanupThread() before it dies, in order
 	   to clean up its PRThread, synchronize with the primordial thread,
 	   etc. */
 	on_exit_thread(_bt_CleanupThread, NULL);

 	return thread;
 }
	/* -- 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 <support/TLS.h>

	#include "prlog.h"
	#include "primpl.h"
	#include "prcvar.h"
	#include "prpdce.h"

	#include <stdlib.h>
	#include <string.h>
	#include <signal.h>

	/* values for PRThread.state */
	#define BT_THREAD_PRIMORD 0x01 /* this is the primordial thread */
	#define BT_THREAD_SYSTEM 0x02 /* this is a system thread */
	#define BT_THREAD_JOINABLE 0x04 /* this is a joinable thread */

	struct _BT_Bookeeping
	{
	PRLock ml; / a lock to protect ourselves */
	sem_id cleanUpSem; /* the primoridal thread will block on this
	sem while waiting for the user threads */
	PRInt32 threadCount; /* user thred count */

	} bt_book = { NULL, B_ERROR, 0 };


	#define BT_TPD_LIMIT 128 /* number of TPD slots we'll provide (arbitrary) */

	/* these will be used to map an index returned by PR_NewThreadPrivateIndex()
	to the corresponding beos native TLS slot number, and to the destructor
	for that slot - note that, because it is allocated globally, this data
	will be automatically zeroed for us when the program begins */
	static int32 tpd_beosTLSSlots[BT_TPD_LIMIT];
	static PRThreadPrivateDTOR tpd_dtors[BT_TPD_LIMIT];

	static vint32 tpd_slotsUsed=0; /* number of currently-allocated TPD slots */
	static int32 tls_prThreadSlot; /* TLS slot in which PRThread will be stored */

	/* this mutex will be used to synchronize access to every
	PRThread.md.joinSem and PRThread.md.is_joining (we could
	actually allocate one per thread, but that seems a bit excessive,
	especially considering that there will probably be little
	contention, PR_JoinThread() is allowed to block anyway, and the code
	protected by the mutex is short/fast) */
	static PRLock *joinSemLock;

	static PRUint32 _bt_MapNSPRToNativePriority( PRThreadPriority priority );
	static PRThreadPriority _bt_MapNativeToNSPRPriority( PRUint32 priority );
	static void _bt_CleanupThread(void *arg);
	static PRThread *_bt_AttachThread();

	void
	_PR_InitThreads (PRThreadType type, PRThreadPriority priority,
	PRUintn maxPTDs)
	{
	PRThread *primordialThread;
	PRUint32 beThreadPriority;

	/* allocate joinSem mutex */
	joinSemLock = PR_NewLock();
	if (joinSemLock == NULL)
	{
	PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
	return;
	}

	/*
	** Create and initialize NSPR structure for our primordial thread.
	*/

	primordialThread = PR_NEWZAP(PRThread);
	if( NULL == primordialThread )
	{
	PR_SetError( PR_OUT_OF_MEMORY_ERROR, 0 );
	return;
	}

	primordialThread->md.joinSem = B_ERROR;

	/*
	** Set the priority to the desired level.
	*/

	beThreadPriority = _bt_MapNSPRToNativePriority( priority );

	set_thread_priority( find_thread( NULL ), beThreadPriority );

	primordialThread->priority = priority;


	/* set the thread's state - note that the thread is not joinable */
	primordialThread->state \|= BT_THREAD_PRIMORD;
	if (type == PR_SYSTEM_THREAD)
	primordialThread->state \|= BT_THREAD_SYSTEM;

	/*
	** Allocate a TLS slot for the PRThread structure (just using
	** native TLS, as opposed to NSPR TPD, will make PR_GetCurrentThread()
	** somewhat faster, and will leave one more TPD slot for our client)
	*/

	tls_prThreadSlot = tls_allocate();

	/*
	** Stuff our new PRThread structure into our thread specific
	** slot.
	*/

	tls_set(tls_prThreadSlot, primordialThread);

	/* allocate lock for bt_book */
	bt_book.ml = PR_NewLock();
	if( NULL == bt_book.ml )
	{
	PR_SetError( PR_OUT_OF_MEMORY_ERROR, 0 );
	return;
	}
	}

	PRUint32
	_bt_MapNSPRToNativePriority( PRThreadPriority priority )
	{
	switch( priority )
	{
	case PR_PRIORITY_LOW: return( B_LOW_PRIORITY );
	case PR_PRIORITY_NORMAL: return( B_NORMAL_PRIORITY );
	case PR_PRIORITY_HIGH: return( B_DISPLAY_PRIORITY );
	case PR_PRIORITY_URGENT: return( B_URGENT_DISPLAY_PRIORITY );
	default: return( B_NORMAL_PRIORITY );
	}
	}

	PRThreadPriority
	_bt_MapNativeToNSPRPriority(PRUint32 priority)
	{
	if (priority < B_NORMAL_PRIORITY)
	return PR_PRIORITY_LOW;
	if (priority < B_DISPLAY_PRIORITY)
	return PR_PRIORITY_NORMAL;
	if (priority < B_URGENT_DISPLAY_PRIORITY)
	return PR_PRIORITY_HIGH;
	return PR_PRIORITY_URGENT;
	}

	PRUint32
	_bt_mapNativeToNSPRPriority( int32 priority )
	{
	switch( priority )
	{
	case PR_PRIORITY_LOW: return( B_LOW_PRIORITY );
	case PR_PRIORITY_NORMAL: return( B_NORMAL_PRIORITY );
	case PR_PRIORITY_HIGH: return( B_DISPLAY_PRIORITY );
	case PR_PRIORITY_URGENT: return( B_URGENT_DISPLAY_PRIORITY );
	default: return( B_NORMAL_PRIORITY );
	}
	}

	/* This method is called by all NSPR threads as they exit */
	void _bt_CleanupThread(void *arg)
	{
	PRThread *me = PR_GetCurrentThread();
	int32 i;

	/* first, clean up all thread-private data */
	for (i = 0; i < tpd_slotsUsed; i++)
	{
	void *oldValue = tls_get(tpd_beosTLSSlots[i]);
	if ( oldValue != NULL && tpd_dtors[i] != NULL )
	(*tpd_dtors[i])(oldValue);
	}

	/* if this thread is joinable, wait for someone to join it */
	if (me->state & BT_THREAD_JOINABLE)
	{
	/* protect access to our joinSem */
	PR_Lock(joinSemLock);

	if (me->md.is_joining)
	{
	/* someone is already waiting to join us (they've
	allocated a joinSem for us) - let them know we're
	ready */
	delete_sem(me->md.joinSem);

	PR_Unlock(joinSemLock);

	}
	else
	{
	/* noone is currently waiting for our demise - it
	is our responsibility to allocate the joinSem
	and block on it */
	me->md.joinSem = create_sem(0, "join sem");

	/* we're done accessing our joinSem */
	PR_Unlock(joinSemLock);

	/* wait for someone to join us */
	while (acquire_sem(me->md.joinSem) == B_INTERRUPTED);
	}
	}

	/* if this is a user thread, we must update our books */
	if ((me->state & BT_THREAD_SYSTEM) == 0)
	{
	/* synchronize access to bt_book */
	PR_Lock( bt_book.ml );

	/* decrement the number of currently-alive user threads */
	bt_book.threadCount--;

	if (bt_book.threadCount == 0 && bt_book.cleanUpSem != B_ERROR) {
	/* we are the last user thread, and the primordial thread is
	blocked in PR_Cleanup() waiting for us to finish - notify
	it */
	delete_sem(bt_book.cleanUpSem);
	}

	PR_Unlock( bt_book.ml );
	}

	/* finally, delete this thread's PRThread */
	PR_DELETE(me);
	}

	/**
	* This is a wrapper that all threads invoke that allows us to set some
	* things up prior to a thread's invocation and clean up after a thread has
	* exited.
	*/
	static void*
	_bt_root (void* arg)
	{
	PRThread thred = (PRThread)arg;
	PRIntn rv;
	void *privData;
	status_t result;
	int i;

	/* save our PRThread object into our TLS */
	tls_set(tls_prThreadSlot, thred);

	thred->startFunc(thred->arg); /* run the dang thing */

	/* clean up */
	_bt_CleanupThread(NULL);

	return 0;
	}

	PR_IMPLEMENT(PRThread*)
	PR_CreateThread (PRThreadType type, void (start)(void arg), void* arg,
	PRThreadPriority priority, PRThreadScope scope,
	PRThreadState state, PRUint32 stackSize)
	{
	PRUint32 bePriority;

	PRThread* thred;

	if (!_pr_initialized) _PR_ImplicitInitialization();

	thred = PR_NEWZAP(PRThread);
	if (thred == NULL)
	{
	PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
	return NULL;
	}

	thred->md.joinSem = B_ERROR;

	thred->arg = arg;
	thred->startFunc = start;
	thred->priority = priority;

	if( state == PR_JOINABLE_THREAD )
	{
	thred->state \|= BT_THREAD_JOINABLE;
	}

	/* keep some books */

	PR_Lock( bt_book.ml );

	if (type == PR_USER_THREAD)
	{
	bt_book.threadCount++;
	}

	PR_Unlock( bt_book.ml );

	bePriority = _bt_MapNSPRToNativePriority( priority );

	thred->md.tid = spawn_thread((thread_func)_bt_root, "moz-thread",
	bePriority, thred);
	if (thred->md.tid < B_OK) {
	PR_SetError(PR_UNKNOWN_ERROR, thred->md.tid);
	PR_DELETE(thred);
	return NULL;
	}

	if (resume_thread(thred->md.tid) < B_OK) {
	PR_SetError(PR_UNKNOWN_ERROR, 0);
	PR_DELETE(thred);
	return NULL;
	}

	return thred;
	}

	PR_IMPLEMENT(PRThread*)
	PR_AttachThread(PRThreadType type, PRThreadPriority priority,
	PRThreadStack *stack)
	{
	/* PR_GetCurrentThread() will attach a thread if necessary */
	return PR_GetCurrentThread();
	}

	PR_IMPLEMENT(void)
	PR_DetachThread()
	{
	/* we don't support detaching */
	}

	PR_IMPLEMENT(PRStatus)
	PR_JoinThread (PRThread* thred)
	{
	status_t eval, status;

	PR_ASSERT(thred != NULL);

	if ((thred->state & BT_THREAD_JOINABLE) == 0)
	{
	PR_SetError( PR_INVALID_ARGUMENT_ERROR, 0 );
	return( PR_FAILURE );
	}

	/* synchronize access to the thread's joinSem */
	PR_Lock(joinSemLock);

	if (thred->md.is_joining)
	{
	/* another thread is already waiting to join the specified
	thread - we must fail */
	PR_Unlock(joinSemLock);
	return PR_FAILURE;
	}

	/* let others know we are waiting to join */
	thred->md.is_joining = PR_TRUE;

	if (thred->md.joinSem == B_ERROR)
	{
	/* the thread hasn't finished yet - it is our responsibility to
	allocate a joinSem and wait on it */
	thred->md.joinSem = create_sem(0, "join sem");

	/* we're done changing the joinSem now */
	PR_Unlock(joinSemLock);

	/* wait for the thread to finish */
	while (acquire_sem(thred->md.joinSem) == B_INTERRUPTED);

	}
	else
	{
	/* the thread has already finished, and has allocated the
	joinSem itself - let it know it can finally die */
	delete_sem(thred->md.joinSem);

	PR_Unlock(joinSemLock);
	}

	/* make sure the thread is dead */
	wait_for_thread(thred->md.tid, &eval);

	return PR_SUCCESS;
	}

	PR_IMPLEMENT(PRThread*)
	PR_GetCurrentThread ()
	{
	PRThread* thred;

	if (!_pr_initialized) _PR_ImplicitInitialization();

	thred = (PRThread *)tls_get( tls_prThreadSlot);
	if (thred == NULL)
	{
	/* this thread doesn't have a PRThread structure (it must be
	a native thread not created by the NSPR) - assimilate it */
	thred = _bt_AttachThread();
	}
	PR_ASSERT(NULL != thred);

	return thred;
	}

	PR_IMPLEMENT(PRThreadScope)
	PR_GetThreadScope (const PRThread* thred)
	{
	PR_ASSERT(thred != NULL);
	return PR_GLOBAL_THREAD;
	}

	PR_IMPLEMENT(PRThreadType)
	PR_GetThreadType (const PRThread* thred)
	{
	PR_ASSERT(thred != NULL);
	return (thred->state & BT_THREAD_SYSTEM) ?
	PR_SYSTEM_THREAD : PR_USER_THREAD;
	}

	PR_IMPLEMENT(PRThreadState)
	PR_GetThreadState (const PRThread* thred)
	{
	PR_ASSERT(thred != NULL);
	return (thred->state & BT_THREAD_JOINABLE)?
	PR_JOINABLE_THREAD: PR_UNJOINABLE_THREAD;
	}

	PR_IMPLEMENT(PRThreadPriority)
	PR_GetThreadPriority (const PRThread* thred)
	{
	PR_ASSERT(thred != NULL);
	return thred->priority;
	} /* PR_GetThreadPriority */

	PR_IMPLEMENT(void) PR_SetThreadPriority(PRThread *thred,
	PRThreadPriority newPri)
	{
	PRUint32 bePriority;

	PR_ASSERT( thred != NULL );

	thred->priority = newPri;
	bePriority = _bt_MapNSPRToNativePriority( newPri );
	set_thread_priority( thred->md.tid, bePriority );
	}

	PR_IMPLEMENT(PRStatus)
	PR_NewThreadPrivateIndex (PRUintn* newIndex,
	PRThreadPrivateDTOR destructor)
	{
	int32 index;

	if (!_pr_initialized) _PR_ImplicitInitialization();

	/* reserve the next available tpd slot */
	index = atomic_add( &tpd_slotsUsed, 1 );
	if (index >= BT_TPD_LIMIT)
	{
	/* no slots left - decrement value, then fail */
	atomic_add( &tpd_slotsUsed, -1 );
	PR_SetError( PR_TPD_RANGE_ERROR, 0 );
	return( PR_FAILURE );
	}

	/* allocate a beos-native TLS slot for this index (the new slot
	automatically contains NULL) */
	tpd_beosTLSSlots[index] = tls_allocate();

	/* remember the destructor */
	tpd_dtors[index] = destructor;

	*newIndex = (PRUintn)index;

	return( PR_SUCCESS );
	}

	PR_IMPLEMENT(PRStatus)
	PR_SetThreadPrivate (PRUintn index, void* priv)
	{
	void *oldValue;

	/*
	** Sanity checking
	*/

	if(index < 0 \|\| index >= tpd_slotsUsed \|\| index >= BT_TPD_LIMIT)
	{
	PR_SetError( PR_TPD_RANGE_ERROR, 0 );
	return( PR_FAILURE );
	}

	/* if the old value isn't NULL, and the dtor for this slot isn't
	NULL, we must destroy the data */
	oldValue = tls_get(tpd_beosTLSSlots[index]);
	if (oldValue != NULL && tpd_dtors[index] != NULL)
	(*tpd_dtors[index])(oldValue);

	/* save new value */
	tls_set(tpd_beosTLSSlots[index], priv);

	return( PR_SUCCESS );
	}

	PR_IMPLEMENT(void*)
	PR_GetThreadPrivate (PRUintn index)
	{
	/* make sure the index is valid */
	if (index < 0 \|\| index >= tpd_slotsUsed \|\| index >= BT_TPD_LIMIT)
	{
	PR_SetError( PR_TPD_RANGE_ERROR, 0 );
	return NULL;
	}

	/* return the value */
	return tls_get( tpd_beosTLSSlots[index] );
	}


	PR_IMPLEMENT(PRStatus)
	PR_Interrupt (PRThread* thred)
	{
	PRIntn rv;

	PR_ASSERT(thred != NULL);

	/*
	** there seems to be a bug in beos R5 in which calling
	** resume_thread() on a blocked thread returns B_OK instead
	** of B_BAD_THREAD_STATE (beos bug #20000422-19095). as such,
	** to interrupt a thread, we will simply suspend then resume it
	** (no longer call resume_thread(), check for B_BAD_THREAD_STATE,
	** the suspend/resume to wake up a blocked thread). this wakes
	** up blocked threads properly, and doesn't hurt unblocked threads
	** (they simply get stopped then re-started immediately)
	*/

	rv = suspend_thread( thred->md.tid );
	if( rv != B_NO_ERROR )
	{
	/* this doesn't appear to be a valid thread_id */
	PR_SetError( PR_UNKNOWN_ERROR, rv );
	return PR_FAILURE;
	}

	rv = resume_thread( thred->md.tid );
	if( rv != B_NO_ERROR )
	{
	PR_SetError( PR_UNKNOWN_ERROR, rv );
	return PR_FAILURE;
	}

	return PR_SUCCESS;
	}

	PR_IMPLEMENT(void)
	PR_ClearInterrupt ()
	{
	}

	PR_IMPLEMENT(PRStatus)
	PR_Yield ()
	{
	/* we just sleep for long enough to cause a reschedule (100
	microseconds) */
	snooze(100);
	}

	#define BT_MILLION 1000000UL

	PR_IMPLEMENT(PRStatus)
	PR_Sleep (PRIntervalTime ticks)
	{
	bigtime_t tps;
	status_t status;

	if (!_pr_initialized) _PR_ImplicitInitialization();

	tps = PR_IntervalToMicroseconds( ticks );

	status = snooze(tps);
	if (status == B_NO_ERROR) return PR_SUCCESS;

	PR_SetError(PR_NOT_IMPLEMENTED_ERROR, status);
	return PR_FAILURE;
	}

	PR_IMPLEMENT(PRStatus)
	PR_Cleanup ()
	{
	PRThread *me = PR_GetCurrentThread();

	PR_ASSERT(me->state & BT_THREAD_PRIMORD);
	if ((me->state & BT_THREAD_PRIMORD) == 0) {
	return PR_FAILURE;
	}

	PR_Lock( bt_book.ml );

	if (bt_book.threadCount != 0)
	{
	/* we'll have to wait for some threads to finish - create a
	sem to block on */
	bt_book.cleanUpSem = create_sem(0, "cleanup sem");
	}

	PR_Unlock( bt_book.ml );

	/* note that, if all the user threads were already dead, we
	wouldn't have created a sem above, so this acquire_sem()
	will fail immediately */
	while (acquire_sem(bt_book.cleanUpSem) == B_INTERRUPTED);

	return PR_SUCCESS;
	}

	PR_IMPLEMENT(void)
	PR_ProcessExit (PRIntn status)
	{
	exit(status);
	}

	PRThread *_bt_AttachThread()
	{
	PRThread *thread;
	thread_info tInfo;

	/* make sure this thread doesn't already have a PRThread structure */
	PR_ASSERT(tls_get(tls_prThreadSlot) == NULL);

	/* allocate a PRThread structure for this thread */
	thread = PR_NEWZAP(PRThread);
	if (thread == NULL)
	{
	PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
	return NULL;
	}

	/* get the native thread's current state */
	get_thread_info(find_thread(NULL), &tInfo);

	/* initialize new PRThread */
	thread->md.tid = tInfo.thread;
	thread->md.joinSem = B_ERROR;
	thread->priority = _bt_MapNativeToNSPRPriority(tInfo.priority);

	/* attached threads are always non-joinable user threads */
	thread->state = 0;

	/* increment user thread count */
	PR_Lock(bt_book.ml);
	bt_book.threadCount++;
	PR_Unlock(bt_book.ml);

	/* store this thread's PRThread */
	tls_set(tls_prThreadSlot, thread);

	/* the thread must call _bt_CleanupThread() before it dies, in order
	to clean up its PRThread, synchronize with the primordial thread,
	etc. */
	on_exit_thread(_bt_CleanupThread, NULL);

	return thread;
	}