thread.xs

UNIX下perl实现代码

#define PERL_NO_GET_CONTEXT
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

/* Magic signature for Thread's mg_private is "Th" */ 
#define Thread_MAGIC_SIGNATURE 0x5468

#ifdef __cplusplus
#ifdef I_UNISTD
#include <unistd.h>
#endif
#endif
#include <fcntl.h>
                        
static int sig_pipe[2];
            
#ifndef THREAD_RET_TYPE
#define THREAD_RET_TYPE void *
#define THREAD_RET_CAST(x) ((THREAD_RET_TYPE) x)
#endif

static void
remove_thread(pTHX_ Thread t)
{
#ifdef USE_THREADS
    DEBUG_S(WITH_THR(PerlIO_printf(Perl_debug_log,
				   "%p: remove_thread %p\n", thr, t)));
    MUTEX_LOCK(&PL_threads_mutex);
    MUTEX_DESTROY(&t->mutex);
    PL_nthreads--;
    t->prev->next = t->next;
    t->next->prev = t->prev;
    SvREFCNT_dec(t->oursv);
    COND_BROADCAST(&PL_nthreads_cond);
    MUTEX_UNLOCK(&PL_threads_mutex);
#endif
}

static THREAD_RET_TYPE
threadstart(void *arg)
{
#ifdef USE_THREADS
#ifdef FAKE_THREADS
    Thread savethread = thr;
    LOGOP myop;
    dSP;
    I32 oldscope = PL_scopestack_ix;
    I32 retval;
    AV *av;
    int i;

    DEBUG_S(PerlIO_printf(Perl_debug_log, "new thread %p starting at %s\n",
			  thr, SvPEEK(TOPs)));
    thr = (Thread) arg;
    savemark = TOPMARK;
    thr->prev = thr->prev_run = savethread;
    thr->next = savethread->next;
    thr->next_run = savethread->next_run;
    savethread->next = savethread->next_run = thr;
    thr->wait_queue = 0;
    thr->private = 0;

    /* Now duplicate most of perl_call_sv but with a few twists */
    PL_op = (OP*)&myop;
    Zero(PL_op, 1, LOGOP);
    myop.op_flags = OPf_STACKED;
    myop.op_next = Nullop;
    myop.op_flags |= OPf_KNOW;
    myop.op_flags |= OPf_WANT_LIST;
    PL_op = pp_entersub(ARGS);
    DEBUG_S(if (!PL_op)
	    PerlIO_printf(Perl_debug_log, "thread starts at Nullop\n"));
    /*
     * When this thread is next scheduled, we start in the right
     * place. When the thread runs off the end of the sub, perl.c
     * handles things, using savemark to figure out how much of the
     * stack is the return value for any join.
     */
    thr = savethread;		/* back to the old thread */
    return 0;
#else
    Thread thr = (Thread) arg;
    LOGOP myop;
    dSP;
    I32 oldmark = TOPMARK;
    I32 oldscope = PL_scopestack_ix;
    I32 retval;
    SV *sv;
    AV *av;
    int i, ret;
    dJMPENV;

#if defined(MULTIPLICITY)
    PERL_SET_INTERP(thr->interp);
#endif

    DEBUG_S(PerlIO_printf(Perl_debug_log, "new thread %p waiting to start\n",
			  thr));

    /*
     * Wait until our creator releases us. If we didn't do this, then
     * it would be potentially possible for out thread to carry on and
     * do stuff before our creator fills in our "self" field. For example,
     * if we went and created another thread which tried to JOIN with us,
     * then we'd be in a mess.
     */
    MUTEX_LOCK(&thr->mutex);
    MUTEX_UNLOCK(&thr->mutex);

    /*
     * It's safe to wait until now to set the thread-specific pointer
     * from our pthread_t structure to our struct perl_thread, since
     * we're the only thread who can get at it anyway.
     */
    PERL_SET_THX(thr);

    DEBUG_S(PerlIO_printf(Perl_debug_log, "new thread %p starting at %s\n",
			  thr, SvPEEK(TOPs)));

    av = newAV();
    sv = POPs;
    PUTBACK;
    ENTER;
    SAVETMPS;
    perl_call_sv(sv, G_ARRAY|G_EVAL);
    SPAGAIN;
    retval = SP - (PL_stack_base + oldmark);
    SP = PL_stack_base + oldmark + 1;
    if (SvCUR(thr->errsv)) {
	MUTEX_LOCK(&thr->mutex);
	thr->flags |= THRf_DID_DIE;
	MUTEX_UNLOCK(&thr->mutex);
	av_store(av, 0, &PL_sv_no);
	av_store(av, 1, newSVsv(thr->errsv));
	DEBUG_S(PerlIO_printf(Perl_debug_log, "%p died: %s\n",
			      thr, SvPV(thr->errsv, PL_na)));
    }
    else {
	DEBUG_S(STMT_START {
	    for (i = 1; i <= retval; i++) {
		PerlIO_printf(Perl_debug_log, "%p return[%d] = %s\n",
				thr, i, SvPEEK(SP[i - 1]));
	    }
	} STMT_END);
	av_store(av, 0, &PL_sv_yes);
	for (i = 1; i <= retval; i++, SP++)
	    sv_setsv(*av_fetch(av, i, TRUE), SvREFCNT_inc(*SP));
    }
    FREETMPS;
    LEAVE;

  finishoff:
#if 0    
    /* removed for debug */
    SvREFCNT_dec(PL_curstack);
#endif
    SvREFCNT_dec(thr->cvcache);
    SvREFCNT_dec(thr->threadsv);
    SvREFCNT_dec(thr->specific);
    SvREFCNT_dec(thr->errsv);

    /*Safefree(cxstack);*/
    while (PL_curstackinfo->si_next)
	PL_curstackinfo = PL_curstackinfo->si_next;
    while (PL_curstackinfo) {
	PERL_SI *p = PL_curstackinfo->si_prev;
	SvREFCNT_dec(PL_curstackinfo->si_stack);
	Safefree(PL_curstackinfo->si_cxstack);
	Safefree(PL_curstackinfo);
	PL_curstackinfo = p;
    }    
    Safefree(PL_markstack);
    Safefree(PL_scopestack);
    Safefree(PL_savestack);
    Safefree(PL_retstack);
    Safefree(PL_tmps_stack);
    Safefree(PL_ofs);

    SvREFCNT_dec(PL_rs);
    SvREFCNT_dec(PL_nrs);
    SvREFCNT_dec(PL_statname);
    SvREFCNT_dec(PL_errors);
    Safefree(PL_screamfirst);
    Safefree(PL_screamnext);
    Safefree(PL_reg_start_tmp);
    SvREFCNT_dec(PL_lastscream);
    SvREFCNT_dec(PL_defoutgv);
    Safefree(PL_reg_poscache);

    MUTEX_LOCK(&thr->mutex);
    DEBUG_S(PerlIO_printf(Perl_debug_log,
			  "%p: threadstart finishing: state is %u\n",
			  thr, ThrSTATE(thr)));
    switch (ThrSTATE(thr)) {
    case THRf_R_JOINABLE:
	ThrSETSTATE(thr, THRf_ZOMBIE);
	MUTEX_UNLOCK(&thr->mutex);
	DEBUG_S(PerlIO_printf(Perl_debug_log,
			      "%p: R_JOINABLE thread finished\n", thr));
	break;
    case THRf_R_JOINED:
	ThrSETSTATE(thr, THRf_DEAD);
	MUTEX_UNLOCK(&thr->mutex);
	remove_thread(aTHX_ thr);
	DEBUG_S(PerlIO_printf(Perl_debug_log,
			      "%p: R_JOINED thread finished\n", thr));
	break;
    case THRf_R_DETACHED:
	ThrSETSTATE(thr, THRf_DEAD);
	MUTEX_UNLOCK(&thr->mutex);
	SvREFCNT_dec(av);
	DEBUG_S(PerlIO_printf(Perl_debug_log,
			      "%p: DETACHED thread finished\n", thr));
	remove_thread(aTHX_ thr);	/* This might trigger main thread to finish */
	break;
    default:
	MUTEX_UNLOCK(&thr->mutex);
	croak("panic: illegal state %u at end of threadstart", ThrSTATE(thr));
	/* NOTREACHED */
    }
    return THREAD_RET_CAST(av);	/* Available for anyone to join with */
					/* us unless we're detached, in which */
					/* case noone sees the value anyway. */
#endif    
#else
    return THREAD_RET_CAST(NULL);
#endif
}

static SV *
newthread (pTHX_ SV *startsv, AV *initargs, char *classname)
{
#ifdef USE_THREADS
    dSP;
    Thread savethread;
    int i;
    SV *sv;
    int err;
#ifndef THREAD_CREATE
    static pthread_attr_t attr;
    static int attr_inited = 0;
    sigset_t fullmask, oldmask;
    static int attr_joinable = PTHREAD_CREATE_JOINABLE;
#endif

    savethread = thr;
    thr = new_struct_thread(thr);
    /* temporarily pretend to be the child thread in case the
     * XPUSHs() below want to grow the child's stack.  This is
     * safe, since the other thread is not yet created, and we
     * are the only ones who know about it */
    PERL_SET_THX(thr);
    SPAGAIN;
    DEBUG_S(PerlIO_printf(Perl_debug_log,
			  "%p: newthread (%p), tid is %u, preparing stack\n",
			  savethread, thr, thr->tid));
    /* The following pushes the arg list and startsv onto the *new* stack */
    PUSHMARK(SP);
    /* Could easily speed up the following greatly */
    for (i = 0; i <= AvFILL(initargs); i++)
	XPUSHs(SvREFCNT_inc(*av_fetch(initargs, i, FALSE)));
    XPUSHs(SvREFCNT_inc(startsv));
    PUTBACK;

    /* On your marks... */
    PERL_SET_THX(savethread);
    MUTEX_LOCK(&thr->mutex);

#ifdef THREAD_CREATE
    err = THREAD_CREATE(thr, threadstart);
#else    
    /* Get set...  */
    sigfillset(&fullmask);
    if (sigprocmask(SIG_SETMASK, &fullmask, &oldmask) == -1)
	croak("panic: sigprocmask");
    err = 0;
    if (!attr_inited) {
	attr_inited = 1;
	err = pthread_attr_init(&attr);
#  ifdef PTHREAD_ATTR_SETDETACHSTATE
	if (err == 0)
	    err = PTHREAD_ATTR_SETDETACHSTATE(&attr, attr_joinable);

#  else
	croak("panic: can't pthread_attr_setdetachstate");
#  endif
    }
    if (err == 0)
	err = PTHREAD_CREATE(&thr->self, attr, threadstart, (void*) thr);
#endif

    if (err) {
	MUTEX_UNLOCK(&thr->mutex);
        DEBUG_S(PerlIO_printf(Perl_debug_log,
			      "%p: create of %p failed %d\n",
			      savethread, thr, err));
	/* Thread creation failed--clean up */
	SvREFCNT_dec(thr->cvcache);
	remove_thread(aTHX_ thr);
	for (i = 0; i <= AvFILL(initargs); i++)
	    SvREFCNT_dec(*av_fetch(initargs, i, FALSE));
	SvREFCNT_dec(startsv);
	return NULL;
    }

#ifdef THREAD_POST_CREATE
    THREAD_POST_CREATE(thr);
#else
    if (sigprocmask(SIG_SETMASK, &oldmask, 0))
	croak("panic: sigprocmask");
#endif

    sv = newSViv(thr->tid);
    sv_magic(sv, thr->oursv, '~', 0, 0);
    SvMAGIC(sv)->mg_private = Thread_MAGIC_SIGNATURE;
    sv = sv_bless(newRV_noinc(sv), gv_stashpv(classname, TRUE));

    /* Go */
    MUTEX_UNLOCK(&thr->mutex);

    return sv;
#else
#  ifdef USE_ITHREADS
    croak("This perl was built for \"ithreads\", which currently does not support Thread.pm.\n"
	  "Run \"perldoc Thread\" for more information");
#  else
    croak("This perl was not built with support for 5.005-style threads.\n"
	  "Run \"perldoc Thread\" for more information");
#  endif
    return &PL_sv_undef;
#endif
}

static Signal_t handle_thread_signal (int sig);