btthread.c

Netscape NSPR库源码

					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_CurrentThread();

    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;
}