src/threads/prcthr.c

/* -*- 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"

#if defined(WIN95)
/*
** Some local variables report warnings on Win95 because the code paths
** using them are conditioned on HAVE_CUSTOME_USER_THREADS.
** The pragma suppresses the warning.
**
*/
#pragma warning(disable : 4101)
#endif


extern PRLock *_pr_sleeplock;  /* allocated and initialized in prinit */
/*
** Routines common to both native and user threads.
**
**
** Clean up a thread object, releasing all of the attached data. Do not
** free the object itself (it may not have been malloc'd)
*/
void _PR_CleanupThread(PRThread *thread)
{
    /* Free up per-thread-data */
    _PR_DestroyThreadPrivate(thread);

    /* Free any thread dump procs */
    if (thread->dumpArg) {
        PR_DELETE(thread->dumpArg);
    }
    thread->dump = 0;

    PR_DELETE(thread->name);
    PR_DELETE(thread->errorString);
    thread->errorStringSize = 0;
    thread->errorStringLength = 0;
    thread->environment = NULL;
}

PR_IMPLEMENT(PRStatus) PR_Yield()
{
    static PRBool warning = PR_TRUE;
    if (warning) warning = _PR_Obsolete(
                                   "PR_Yield()", "PR_Sleep(PR_INTERVAL_NO_WAIT)");
    return (PR_Sleep(PR_INTERVAL_NO_WAIT));
}

/*
** Make the current thread sleep until "timeout" ticks amount of time
** has expired. If "timeout" is PR_INTERVAL_NO_WAIT then the call is
** equivalent to a yield. Waiting for an infinite amount of time is
** allowed in the expectation that another thread will interrupt().
**
** A single lock is used for all threads calling sleep. Each caller
** does get its own condition variable since each is expected to have
** a unique 'timeout'.
*/
PR_IMPLEMENT(PRStatus) PR_Sleep(PRIntervalTime timeout)
{
    PRStatus rv = PR_SUCCESS;

    if (!_pr_initialized) {
        _PR_ImplicitInitialization();
    }

    if (PR_INTERVAL_NO_WAIT == timeout)
    {
        /*
        ** This is a simple yield, nothing more, nothing less.
        */
        PRIntn is;
        PRThread *me = PR_GetCurrentThread();
        PRUintn pri = me->priority;
        _PRCPU *cpu = _PR_MD_CURRENT_CPU();

        if ( _PR_IS_NATIVE_THREAD(me) ) {
            _PR_MD_YIELD();
        }
        else
        {
            _PR_INTSOFF(is);
            _PR_RUNQ_LOCK(cpu);
            if (_PR_RUNQREADYMASK(cpu) >> pri) {
                me->cpu = cpu;
                me->state = _PR_RUNNABLE;
                _PR_ADD_RUNQ(me, cpu, pri);
                _PR_RUNQ_UNLOCK(cpu);

                PR_LOG(_pr_sched_lm, PR_LOG_MIN, ("PR_Yield: yielding"));
                _PR_MD_SWITCH_CONTEXT(me);
                PR_LOG(_pr_sched_lm, PR_LOG_MIN, ("PR_Yield: done"));

                _PR_FAST_INTSON(is);
            }
            else
            {
                _PR_RUNQ_UNLOCK(cpu);
                _PR_INTSON(is);
            }
        }
    }
    else
    {
        /*
        ** This is waiting for some finite period of time.
        ** A thread in this state is interruptible (PR_Interrupt()),
        ** but the lock and cvar used are local to the implementation
        ** and not visible to the caller, therefore not notifiable.
        */
        PRCondVar *cv;
        PRIntervalTime timein;

        timein = PR_IntervalNow();
        cv = PR_NewCondVar(_pr_sleeplock);
        PR_ASSERT(cv != NULL);
        PR_Lock(_pr_sleeplock);
        do
        {
            PRIntervalTime delta = PR_IntervalNow() - timein;
            if (delta > timeout) {
                break;
            }
            rv = PR_WaitCondVar(cv, timeout - delta);
        } while (rv == PR_SUCCESS);
        PR_Unlock(_pr_sleeplock);
        PR_DestroyCondVar(cv);
    }
    return rv;
}

PR_IMPLEMENT(PRUint32) PR_GetThreadID(PRThread *thread)
{
    return thread->id;
}

PR_IMPLEMENT(PRThreadPriority) PR_GetThreadPriority(const PRThread *thread)
{
    return (PRThreadPriority) thread->priority;
}

PR_IMPLEMENT(PRThread *) PR_GetCurrentThread()
{
    if (!_pr_initialized) {
        _PR_ImplicitInitialization();
    }
    return _PR_MD_CURRENT_THREAD();
}

/*
** Set the interrupt flag for a thread. The thread will be unable to
** block in i/o functions when this happens. Also, any PR_Wait's in
** progress will be undone. The interrupt remains in force until
** PR_ClearInterrupt is called.
*/
PR_IMPLEMENT(PRStatus) PR_Interrupt(PRThread *thread)
{
#ifdef _PR_GLOBAL_THREADS_ONLY
    PRCondVar *victim;

    _PR_THREAD_LOCK(thread);
    thread->flags |= _PR_INTERRUPT;
    victim = thread->wait.cvar;
    _PR_THREAD_UNLOCK(thread);
    if ((NULL != victim) && (!(thread->flags & _PR_INTERRUPT_BLOCKED))) {
        int haveLock = (victim->lock->owner == _PR_MD_CURRENT_THREAD());

        if (!haveLock) {
            PR_Lock(victim->lock);
        }
        PR_NotifyAllCondVar(victim);
        if (!haveLock) {
            PR_Unlock(victim->lock);
        }
    }
    return PR_SUCCESS;
#else  /* ! _PR_GLOBAL_THREADS_ONLY */
    PRIntn is;
    PRThread *me = _PR_MD_CURRENT_THREAD();

    if (!_PR_IS_NATIVE_THREAD(me)) {
        _PR_INTSOFF(is);
    }

    _PR_THREAD_LOCK(thread);
    thread->flags |= _PR_INTERRUPT;
    switch (thread->state) {
        case _PR_COND_WAIT:
            /*
             * call is made with thread locked;
             * on return lock is released
             */
            if (!(thread->flags & _PR_INTERRUPT_BLOCKED)) {
                _PR_NotifyLockedThread(thread);
            }
            break;
        case _PR_IO_WAIT:
            /*
             * Need to hold the thread lock when calling
             * _PR_Unblock_IO_Wait().  On return lock is
             * released.
             */
#if defined(XP_UNIX) || defined(WINNT) || defined(WIN16)
            if (!(thread->flags & _PR_INTERRUPT_BLOCKED)) {
                _PR_Unblock_IO_Wait(thread);
            }
#else
            _PR_THREAD_UNLOCK(thread);
#endif
            break;
        case _PR_RUNNING:
        case _PR_RUNNABLE:
        case _PR_LOCK_WAIT:
        default:
            _PR_THREAD_UNLOCK(thread);
            break;
    }
    if (!_PR_IS_NATIVE_THREAD(me)) {
        _PR_INTSON(is);
    }
    return PR_SUCCESS;
#endif  /* _PR_GLOBAL_THREADS_ONLY */
}

/*
** Clear the interrupt flag for self.
*/
PR_IMPLEMENT(void) PR_ClearInterrupt()
{
    PRIntn is;
    PRThread *me = _PR_MD_CURRENT_THREAD();

    if ( !_PR_IS_NATIVE_THREAD(me)) {
        _PR_INTSOFF(is);
    }
    _PR_THREAD_LOCK(me);
    me->flags &= ~_PR_INTERRUPT;
    _PR_THREAD_UNLOCK(me);
    if ( !_PR_IS_NATIVE_THREAD(me)) {
        _PR_INTSON(is);
    }
}

PR_IMPLEMENT(void) PR_BlockInterrupt()
{
    PRIntn is;
    PRThread *me = _PR_MD_CURRENT_THREAD();

    if ( !_PR_IS_NATIVE_THREAD(me)) {
        _PR_INTSOFF(is);
    }
    _PR_THREAD_LOCK(me);
    _PR_THREAD_BLOCK_INTERRUPT(me);
    _PR_THREAD_UNLOCK(me);
    if ( !_PR_IS_NATIVE_THREAD(me)) {
        _PR_INTSON(is);
    }
}  /* PR_BlockInterrupt */

PR_IMPLEMENT(void) PR_UnblockInterrupt()
{
    PRIntn is;
    PRThread *me = _PR_MD_CURRENT_THREAD();

    if ( !_PR_IS_NATIVE_THREAD(me)) {
        _PR_INTSOFF(is);
    }
    _PR_THREAD_LOCK(me);
    _PR_THREAD_UNBLOCK_INTERRUPT(me);
    _PR_THREAD_UNLOCK(me);
    if ( !_PR_IS_NATIVE_THREAD(me)) {
        _PR_INTSON(is);
    }
}  /* PR_UnblockInterrupt */

/*
** Return the thread stack pointer of the given thread.
*/
PR_IMPLEMENT(void *) PR_GetSP(PRThread *thread)
{
    return (void *)_PR_MD_GET_SP(thread);
}

PR_IMPLEMENT(void*) GetExecutionEnvironment(PRThread *thread)
{
    return thread->environment;
}

PR_IMPLEMENT(void) SetExecutionEnvironment(PRThread *thread, void *env)
{
    thread->environment = env;
}


PR_IMPLEMENT(PRInt32) PR_GetThreadAffinityMask(PRThread *thread, PRUint32 *mask)
{
#ifdef HAVE_THREAD_AFFINITY
    return _PR_MD_GETTHREADAFFINITYMASK(thread, mask);
#else
    return 0;
#endif
}

PR_IMPLEMENT(PRInt32) PR_SetThreadAffinityMask(PRThread *thread, PRUint32 mask )
{
#ifdef HAVE_THREAD_AFFINITY
    return _PR_MD_SETTHREADAFFINITYMASK(thread, mask);
#else
    return 0;
#endif
}

/* This call is thread unsafe if another thread is calling SetConcurrency()
 */
PR_IMPLEMENT(PRInt32) PR_SetCPUAffinityMask(PRUint32 mask)
{
#ifdef HAVE_THREAD_AFFINITY
    PRCList *qp;
    extern PRUint32 _pr_cpu_affinity_mask;

    if (!_pr_initialized) {
        _PR_ImplicitInitialization();
    }

    _pr_cpu_affinity_mask = mask;

    qp = _PR_CPUQ().next;
    while(qp != &_PR_CPUQ()) {
        _PRCPU *cpu;

        cpu = _PR_CPU_PTR(qp);
        PR_SetThreadAffinityMask(cpu->thread, mask);

        qp = qp->next;
    }
#endif

    return 0;
}

PRUint32 _pr_recycleThreads = 0;
PR_IMPLEMENT(void) PR_SetThreadRecycleMode(PRUint32 count)
{
    _pr_recycleThreads = count;
}

PR_IMPLEMENT(PRThread*) PR_CreateThreadGCAble(PRThreadType type,
        void (*start)(void *arg),
        void *arg,
        PRThreadPriority priority,
        PRThreadScope scope,
        PRThreadState state,
        PRUint32 stackSize)
{
    return _PR_CreateThread(type, start, arg, priority, scope, state,
                            stackSize, _PR_GCABLE_THREAD);
}

#ifdef SOLARIS
PR_IMPLEMENT(PRThread*) PR_CreateThreadBound(PRThreadType type,
        void (*start)(void *arg),
        void *arg,
        PRUintn priority,
        PRThreadScope scope,
        PRThreadState state,
        PRUint32 stackSize)
{
    return _PR_CreateThread(type, start, arg, priority, scope, state,
                            stackSize, _PR_BOUND_THREAD);
}
#endif


PR_IMPLEMENT(PRThread*) PR_AttachThreadGCAble(
    PRThreadType type, PRThreadPriority priority, PRThreadStack *stack)
{
    /* $$$$ not sure how to finese this one */
    PR_SetError(PR_NOT_IMPLEMENTED_ERROR, 0);
    return NULL;
}

PR_IMPLEMENT(void) PR_SetThreadGCAble()
{
    if (!_pr_initialized) {
        _PR_ImplicitInitialization();
    }
    PR_Lock(_pr_activeLock);
    _PR_MD_CURRENT_THREAD()->flags |= _PR_GCABLE_THREAD;
    PR_Unlock(_pr_activeLock);
}

PR_IMPLEMENT(void) PR_ClearThreadGCAble()
{
    if (!_pr_initialized) {
        _PR_ImplicitInitialization();
    }
    PR_Lock(_pr_activeLock);
    _PR_MD_CURRENT_THREAD()->flags &= (~_PR_GCABLE_THREAD);
    PR_Unlock(_pr_activeLock);
}

PR_IMPLEMENT(PRThreadScope) PR_GetThreadScope(const PRThread *thread)
{
    if (!_pr_initialized) {
        _PR_ImplicitInitialization();
    }

    if (_PR_IS_NATIVE_THREAD(thread)) {
        return (thread->flags & _PR_BOUND_THREAD) ? PR_GLOBAL_BOUND_THREAD :
               PR_GLOBAL_THREAD;
    } else {
        return PR_LOCAL_THREAD;
    }
}

PR_IMPLEMENT(PRThreadType) PR_GetThreadType(const PRThread *thread)
{
    return (thread->flags & _PR_SYSTEM) ? PR_SYSTEM_THREAD : PR_USER_THREAD;
}

PR_IMPLEMENT(PRThreadState) PR_GetThreadState(const PRThread *thread)
{
    return (NULL == thread->term) ? PR_UNJOINABLE_THREAD : PR_JOINABLE_THREAD;
}  /* PR_GetThreadState */