In non-blocking recv functions in libmux and libdraw,

distinguish between "cannot receive without blocking"
and "EOF on connection".

In libmux, do not elect async guys muxers, so that
synchronous RPC calls run in the main event loop
(e.g., in eresized) do not get stuck.

Fixes problem reported by Lu Xuxiao, namely that
jpg etc. would spin at 100% cpu usage.

1 files changed, 20 insertions, 23 deletions

diff --git a/src/libmux/io.c b/src/libmux/io.c
index 4a89ca22..d9d9d8a6 100644
--- a/src/libmux/io.c
+++ b/src/libmux/io.c
@@ -34,7 +34,7 @@ _muxrecvproc(void *v)
 	qunlock(&mux->inlk);
 	qlock(&mux->lk);
 	_muxqhangup(q);
-	while((p = _muxnbqrecv(q)) != nil)
+	while(_muxnbqrecv(q, &p))
 		free(p);
 	free(q);
 	mux->readq = nil;
@@ -64,7 +64,7 @@ _muxsendproc(void *v)
 	qunlock(&mux->outlk);
 	qlock(&mux->lk);
 	_muxqhangup(q);
-	while((p = _muxnbqrecv(q)) != nil)
+	while(_muxnbqrecv(q, &p))
 		free(p);
 	free(q);
 	mux->writeq = nil;
@@ -73,42 +73,39 @@ _muxsendproc(void *v)
 	return;
 }
 
-void*
-_muxrecv(Mux *mux, int canblock)
+int
+_muxrecv(Mux *mux, int canblock, void **vp)
 {
 	void *p;
+	int ret;
 
 	qlock(&mux->lk);
-/*
-	if(mux->state != VtStateConnected){
-		werrstr("not connected");
-		qunlock(&mux->lk);
-		return nil;
-	}
-*/
 	if(mux->readq){
 		qunlock(&mux->lk);
-		if(canblock)
-			return _muxqrecv(mux->readq);
-		return _muxnbqrecv(mux->readq);
+		if(canblock){
+			*vp = _muxqrecv(mux->readq);
+			return 1;
+		}
+		return _muxnbqrecv(mux->readq, vp);
 	}
 
 	qlock(&mux->inlk);
 	qunlock(&mux->lk);
-	if(canblock)
+	if(canblock){
 		p = mux->recv(mux);
-	else{
+		ret = 1;
+	}else{
 		if(mux->nbrecv)
-			p = mux->nbrecv(mux);
-		else
+			ret = mux->nbrecv(mux, &p);
+		else{
+			/* send eof, not "no packet ready" */
 			p = nil;
+			ret = 1;
+		}
 	}
 	qunlock(&mux->inlk);
-/*
-	if(!p && canblock)
-		vthangup(mux);
-*/
-	return p;
+	*vp = p;
+	return ret;
 }
 
 int