From 3a19470202c5c0f6e9375e5d57535c3d508f2edf Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Sat, 4 Nov 2006 18:46:00 +0000
Subject: 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.
---
 src/libmux/io.c | 43 ++++++++++++++++++++-----------------------
 1 file changed, 20 insertions(+), 23 deletions(-)

(limited to 'src/libmux/io.c')

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
-- 
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