static bool
chanrecv ( ChanType *t , Hchan* c , byte *ep , bool block , bool *received )
{
SudoG *sg;
SudoG mysg;
G *gp;
int64 t0;
#line 215 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( debug )
runtime·printf ( "chanrecv: chan=%p\n" , c ) ;
#line 218 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( c == nil ) {
USED ( t ) ;
if ( !block )
return false;
runtime·park ( nil , nil , "chan receive (nil chan)" ) ;
return false;
}
#line 226 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
t0 = 0;
mysg.releasetime = 0;
if ( runtime·blockprofilerate > 0 ) {
t0 = runtime·cputicks ( ) ;
mysg.releasetime = -1;
}
#line 233 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
runtime·lock ( c ) ;
if ( c->dataqsiz > 0 )
goto asynch;
#line 237 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( c->closed )
goto closed;
#line 240 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
sg = dequeue ( &c->sendq ) ;
if ( sg != nil ) {
if ( raceenabled )
racesync ( c , sg ) ;
runtime·unlock ( c ) ;
#line 246 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( ep != nil )
c->elemtype->alg->copy ( c->elemsize , ep , sg->elem ) ;
gp = sg->g;
gp->param = sg;
if ( sg->releasetime )
sg->releasetime = runtime·cputicks ( ) ;
runtime·ready ( gp ) ;
#line 254 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( received != nil )
*received = true;
return true;
}
#line 259 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( !block ) {
runtime·unlock ( c ) ;
return false;
}
#line 264 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
mysg.elem = ep;
mysg.g = g;
mysg.selectdone = nil;
g->param = nil;
enqueue ( &c->recvq , &mysg ) ;
runtime·parkunlock ( c , "chan receive" ) ;
#line 271 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( g->param == nil ) {
runtime·lock ( c ) ;
if ( !c->closed )
runtime·throw ( "chanrecv: spurious wakeup" ) ;
goto closed;
}
#line 278 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( received != nil )
*received = true;
if ( mysg.releasetime > 0 )
runtime·blockevent ( mysg.releasetime - t0 , 2 ) ;
return true;
#line 284 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
asynch:
if ( c->qcount <= 0 ) {
if ( c->closed )
goto closed;
#line 289 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( !block ) {
runtime·unlock ( c ) ;
if ( received != nil )
*received = false;
return false;
}
mysg.g = g;
mysg.elem = nil;
mysg.selectdone = nil;
enqueue ( &c->recvq , &mysg ) ;
runtime·parkunlock ( c , "chan receive" ) ;
#line 301 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
runtime·lock ( c ) ;
goto asynch;
}
#line 305 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( raceenabled ) {
runtime·raceacquire ( chanbuf ( c , c->recvx ) ) ;
if ( c->dataqsiz == 1 )
runtime·racerelease ( chanbuf ( c , c->recvx ) ) ;
}
#line 311 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( ep != nil )
c->elemtype->alg->copy ( c->elemsize , ep , chanbuf ( c , c->recvx ) ) ;
c->elemtype->alg->copy ( c->elemsize , chanbuf ( c , c->recvx ) , nil ) ;
if ( ++c->recvx == c->dataqsiz )
c->recvx = 0;
c->qcount--;
#line 318 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
sg = dequeue ( &c->sendq ) ;
if ( sg != nil ) {
gp = sg->g;
runtime·unlock ( c ) ;
if ( sg->releasetime )
sg->releasetime = runtime·cputicks ( ) ;
runtime·ready ( gp ) ;
} else
runtime·unlock ( c ) ;
#line 328 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
if ( received != nil )
*received = true;
if ( mysg.releasetime > 0 )
runtime·blockevent ( mysg.releasetime - t0 , 2 ) ;
return true;
#line 334 "/home/14/ren/source/golang/go/src/pkg/runtime/chan.goc"
closed:
if ( ep != nil )
c->elemtype->alg->copy ( c->elemsize , ep , nil ) ;
if ( received != nil )
*received = false;
if ( raceenabled )
runtime·raceacquire ( c ) ;
runtime·unlock ( c ) ;
if ( mysg.releasetime > 0 )
runtime·blockevent ( mysg.releasetime - t0 , 2 ) ;
return true;
}
static void*
selectgo(Select **selp)
{
Select *sel;
uint32 o, i, j, k;
Scase *cas, *dfl;
Hchan *c;
SudoG *sg;
G *gp;
byte *as;
void *pc;
sel = *selp;
if(runtime·gcwaiting)
runtime·gosched();
if(debug)
runtime·printf("select: sel=%p\n", sel);
// The compiler rewrites selects that statically have
// only 0 or 1 cases plus default into simpler constructs.
// The only way we can end up with such small sel->ncase
// values here is for a larger select in which most channels
// have been nilled out. The general code handles those
// cases correctly, and they are rare enough not to bother
// optimizing (and needing to test).
// generate permuted order
for(i=0; i<sel->ncase; i++)
sel->pollorder[i] = i;
for(i=1; i<sel->ncase; i++) {
o = sel->pollorder[i];
j = runtime·fastrand1()%(i+1);
sel->pollorder[i] = sel->pollorder[j];
sel->pollorder[j] = o;
}
// sort the cases by Hchan address to get the locking order.
// simple heap sort, to guarantee n log n time and constant stack footprint.
for(i=0; i<sel->ncase; i++) {
j = i;
c = sel->scase[j].chan;
while(j > 0 && sel->lockorder[k=(j-1)/2] < c) {
sel->lockorder[j] = sel->lockorder[k];
j = k;
}
sel->lockorder[j] = c;
}
for(i=sel->ncase; i-->0; ) {
c = sel->lockorder[i];
sel->lockorder[i] = sel->lockorder[0];
j = 0;
for(;;) {
k = j*2+1;
if(k >= i)
break;
if(k+1 < i && sel->lockorder[k] < sel->lockorder[k+1])
k++;
if(c < sel->lockorder[k]) {
sel->lockorder[j] = sel->lockorder[k];
j = k;
continue;
}
break;
}
sel->lockorder[j] = c;
}
/*
for(i=0; i+1<sel->ncase; i++)
if(sel->lockorder[i] > sel->lockorder[i+1]) {
runtime·printf("i=%d %p %p\n", i, sel->lockorder[i], sel->lockorder[i+1]);
runtime·throw("select: broken sort");
}
*/
sellock(sel);
loop:
// pass 1 - look for something already waiting
dfl = nil;
for(i=0; i<sel->ncase; i++) {
o = sel->pollorder[i];
cas = &sel->scase[o];
c = cas->chan;
switch(cas->kind) {
case CaseRecv:
if(c->dataqsiz > 0) {
if(c->qcount > 0)
goto asyncrecv;
} else {
sg = dequeue(&c->sendq);
if(sg != nil)
goto syncrecv;
}
if(c->closed)
goto rclose;
break;
case CaseSend:
if(c->closed)
goto sclose;
if(c->dataqsiz > 0) {
if(c->qcount < c->dataqsiz)
goto asyncsend;
} else {
sg = dequeue(&c->recvq);
if(sg != nil)
goto syncsend;
}
break;
case CaseDefault:
dfl = cas;
break;
}
}
if(dfl != nil) {
selunlock(sel);
cas = dfl;
goto retc;
}
// pass 2 - enqueue on all chans
for(i=0; i<sel->ncase; i++) {
o = sel->pollorder[i];
cas = &sel->scase[o];
c = cas->chan;
sg = &cas->sg;
sg->g = g;
sg->selgen = g->selgen;
switch(cas->kind) {
case CaseRecv:
enqueue(&c->recvq, sg);
break;
case CaseSend:
enqueue(&c->sendq, sg);
break;
}
}
g->param = nil;
runtime·park((void(*)(Lock*))selunlock, (Lock*)sel, "select");
sellock(sel);
sg = g->param;
// pass 3 - dequeue from unsuccessful chans
// otherwise they stack up on quiet channels
for(i=0; i<sel->ncase; i++) {
cas = &sel->scase[i];
if(cas != (Scase*)sg) {
c = cas->chan;
if(cas->kind == CaseSend)
dequeueg(&c->sendq);
else
dequeueg(&c->recvq);
}
}
if(sg == nil)
goto loop;
cas = (Scase*)sg;
c = cas->chan;
if(c->dataqsiz > 0)
runtime·throw("selectgo: shouldn't happen");
if(debug)
runtime·printf("wait-return: sel=%p c=%p cas=%p kind=%d\n",
sel, c, cas, cas->kind);
if(cas->kind == CaseRecv) {
if(cas->receivedp != nil)
*cas->receivedp = true;
}
selunlock(sel);
goto retc;
asyncrecv:
// can receive from buffer
if(raceenabled)
runtime·raceacquire(chanbuf(c, c->recvx));
if(cas->receivedp != nil)
*cas->receivedp = true;
if(cas->sg.elem != nil)
c->elemalg->copy(c->elemsize, cas->sg.elem, chanbuf(c, c->recvx));
c->elemalg->copy(c->elemsize, chanbuf(c, c->recvx), nil);
if(++c->recvx == c->dataqsiz)
c->recvx = 0;
c->qcount--;
sg = dequeue(&c->sendq);
if(sg != nil) {
gp = sg->g;
selunlock(sel);
runtime·ready(gp);
} else {
selunlock(sel);
}
goto retc;
asyncsend:
// can send to buffer
if(raceenabled)
runtime·racerelease(chanbuf(c, c->sendx));
c->elemalg->copy(c->elemsize, chanbuf(c, c->sendx), cas->sg.elem);
if(++c->sendx == c->dataqsiz)
c->sendx = 0;
c->qcount++;
sg = dequeue(&c->recvq);
if(sg != nil) {
gp = sg->g;
selunlock(sel);
runtime·ready(gp);
} else {
selunlock(sel);
}
goto retc;
syncrecv:
// can receive from sleeping sender (sg)
if(raceenabled)
racesync(c, sg);
selunlock(sel);
if(debug)
runtime·printf("syncrecv: sel=%p c=%p o=%d\n", sel, c, o);
if(cas->receivedp != nil)
*cas->receivedp = true;
if(cas->sg.elem != nil)
c->elemalg->copy(c->elemsize, cas->sg.elem, sg->elem);
gp = sg->g;
gp->param = sg;
runtime·ready(gp);
goto retc;
rclose:
// read at end of closed channel
selunlock(sel);
if(cas->receivedp != nil)
*cas->receivedp = false;
if(cas->sg.elem != nil)
c->elemalg->copy(c->elemsize, cas->sg.elem, nil);
if(raceenabled)
runtime·raceacquire(c);
goto retc;
syncsend:
// can send to sleeping receiver (sg)
if(raceenabled)
racesync(c, sg);
selunlock(sel);
if(debug)
runtime·printf("syncsend: sel=%p c=%p o=%d\n", sel, c, o);
if(sg->elem != nil)
c->elemalg->copy(c->elemsize, sg->elem, cas->sg.elem);
gp = sg->g;
gp->param = sg;
runtime·ready(gp);
retc:
// return pc corresponding to chosen case.
// Set boolean passed during select creation
// (at offset selp + cas->so) to true.
// If cas->so == 0, this is a reflect-driven select and we
// don't need to update the boolean.
pc = cas->pc;
if(cas->so > 0) {
as = (byte*)selp + cas->so;
*as = true;
}
runtime·free(sel);
return pc;
sclose:
// send on closed channel
selunlock(sel);
runtime·panicstring("send on closed channel");
return nil; // not reached
}
void
runtime·block(void)
{
runtime·park(nil, nil, "select (no cases)"); // forever
}
void
runtime·chanrecv(ChanType *t, Hchan* c, byte *ep, bool *selected, bool *received)
{
SudoG *sg;
SudoG mysg;
G *gp;
int64 t0;
if(runtime·gcwaiting)
runtime·gosched();
if(debug)
runtime·printf("chanrecv: chan=%p\n", c);
if(c == nil) {
USED(t);
if(selected != nil) {
*selected = false;
return;
}
runtime·park(nil, nil, "chan receive (nil chan)");
return; // not reached
}
t0 = 0;
mysg.releasetime = 0;
if(runtime·blockprofilerate > 0) {
t0 = runtime·cputicks();
mysg.releasetime = -1;
}
runtime·lock(c);
if(c->dataqsiz > 0)
goto asynch;
if(c->closed)
goto closed;
sg = dequeue(&c->sendq);
if(sg != nil) {
if(raceenabled)
racesync(c, sg);
runtime·unlock(c);
if(ep != nil)
c->elemalg->copy(c->elemsize, ep, sg->elem);
gp = sg->g;
gp->param = sg;
if(sg->releasetime)
sg->releasetime = runtime·cputicks();
runtime·ready(gp);
if(selected != nil)
*selected = true;
if(received != nil)
*received = true;
return;
}
if(selected != nil) {
runtime·unlock(c);
*selected = false;
return;
}
mysg.elem = ep;
mysg.g = g;
mysg.selgen = NOSELGEN;
g->param = nil;
enqueue(&c->recvq, &mysg);
runtime·park(runtime·unlock, c, "chan receive");
if(g->param == nil) {
runtime·lock(c);
if(!c->closed)
runtime·throw("chanrecv: spurious wakeup");
goto closed;
}
if(received != nil)
*received = true;
if(mysg.releasetime > 0)
runtime·blockevent(mysg.releasetime - t0, 2);
return;
asynch:
if(c->qcount <= 0) {
if(c->closed)
goto closed;
if(selected != nil) {
runtime·unlock(c);
*selected = false;
if(received != nil)
*received = false;
return;
}
mysg.g = g;
mysg.elem = nil;
mysg.selgen = NOSELGEN;
enqueue(&c->recvq, &mysg);
runtime·park(runtime·unlock, c, "chan receive");
runtime·lock(c);
goto asynch;
}
if(raceenabled)
runtime·raceacquire(chanbuf(c, c->recvx));
if(ep != nil)
c->elemalg->copy(c->elemsize, ep, chanbuf(c, c->recvx));
c->elemalg->copy(c->elemsize, chanbuf(c, c->recvx), nil);
if(++c->recvx == c->dataqsiz)
c->recvx = 0;
c->qcount--;
sg = dequeue(&c->sendq);
if(sg != nil) {
gp = sg->g;
runtime·unlock(c);
if(sg->releasetime)
sg->releasetime = runtime·cputicks();
runtime·ready(gp);
} else
runtime·unlock(c);
if(selected != nil)
*selected = true;
if(received != nil)
*received = true;
if(mysg.releasetime > 0)
runtime·blockevent(mysg.releasetime - t0, 2);
return;
closed:
if(ep != nil)
c->elemalg->copy(c->elemsize, ep, nil);
if(selected != nil)
*selected = true;
if(received != nil)
*received = false;
if(raceenabled)
runtime·raceacquire(c);
runtime·unlock(c);
if(mysg.releasetime > 0)
runtime·blockevent(mysg.releasetime - t0, 2);
}
/*
* generic single channel send/recv
* if the bool pointer is nil,
* then the full exchange will
* occur. if pres is not nil,
* then the protocol will not
* sleep but return if it could
* not complete.
*
* sleep can wake up with g->param == nil
* when a channel involved in the sleep has
* been closed. it is easiest to loop and re-run
* the operation; we'll see that it's now closed.
*/
void
runtime·chansend(ChanType *t, Hchan *c, byte *ep, bool *pres, void *pc)
{
SudoG *sg;
SudoG mysg;
G* gp;
int64 t0;
if(c == nil) {
USED(t);
if(pres != nil) {
*pres = false;
return;
}
runtime·park(nil, nil, "chan send (nil chan)");
return; // not reached
}
if(runtime·gcwaiting)
runtime·gosched();
if(debug) {
runtime·printf("chansend: chan=%p; elem=", c);
c->elemalg->print(c->elemsize, ep);
runtime·prints("\n");
}
t0 = 0;
mysg.releasetime = 0;
if(runtime·blockprofilerate > 0) {
t0 = runtime·cputicks();
mysg.releasetime = -1;
}
runtime·lock(c);
// TODO(dvyukov): add similar instrumentation to select.
if(raceenabled)
runtime·racereadpc(c, pc, runtime·chansend);
if(c->closed)
goto closed;
if(c->dataqsiz > 0)
goto asynch;
sg = dequeue(&c->recvq);
if(sg != nil) {
if(raceenabled)
racesync(c, sg);
runtime·unlock(c);
gp = sg->g;
gp->param = sg;
if(sg->elem != nil)
c->elemalg->copy(c->elemsize, sg->elem, ep);
if(sg->releasetime)
sg->releasetime = runtime·cputicks();
runtime·ready(gp);
if(pres != nil)
*pres = true;
return;
}
if(pres != nil) {
runtime·unlock(c);
*pres = false;
return;
}
mysg.elem = ep;
mysg.g = g;
mysg.selgen = NOSELGEN;
g->param = nil;
enqueue(&c->sendq, &mysg);
runtime·park(runtime·unlock, c, "chan send");
if(g->param == nil) {
runtime·lock(c);
if(!c->closed)
runtime·throw("chansend: spurious wakeup");
goto closed;
}
if(mysg.releasetime > 0)
runtime·blockevent(mysg.releasetime - t0, 2);
return;
asynch:
if(c->closed)
goto closed;
if(c->qcount >= c->dataqsiz) {
if(pres != nil) {
runtime·unlock(c);
*pres = false;
return;
}
mysg.g = g;
mysg.elem = nil;
mysg.selgen = NOSELGEN;
enqueue(&c->sendq, &mysg);
runtime·park(runtime·unlock, c, "chan send");
runtime·lock(c);
goto asynch;
}
if(raceenabled)
runtime·racerelease(chanbuf(c, c->sendx));
c->elemalg->copy(c->elemsize, chanbuf(c, c->sendx), ep);
if(++c->sendx == c->dataqsiz)
c->sendx = 0;
c->qcount++;
sg = dequeue(&c->recvq);
if(sg != nil) {
gp = sg->g;
runtime·unlock(c);
if(sg->releasetime)
sg->releasetime = runtime·cputicks();
runtime·ready(gp);
} else
runtime·unlock(c);
if(pres != nil)
*pres = true;
if(mysg.releasetime > 0)
runtime·blockevent(mysg.releasetime - t0, 2);
return;
closed:
runtime·unlock(c);
runtime·panicstring("send on closed channel");
}
void jerk()
{
forward100();
wait1Msec(100);
park();
}
