rio: ensure single reader and single writer for kbdtap

Multiple readers eat each other's lunch, and it makes more
sense to limit use to one 'pipeline' then just one reader.

This also brings back the 'focus' message from kbdtap used
by ktrans to reset its line buffers when the user switches
windows. An event file was considered, but deemed harmful
to the artwork. To paraphrase an old excuse found in the code:
"rio just isn't structured for that. Apologies."

1 files changed, 17 insertions, 5 deletions

diff --git a/sys/src/cmd/rio/xfid.c b/sys/src/cmd/rio/xfid.c
index cee3c006d..7afe02353 100644
--- a/sys/src/cmd/rio/xfid.c
+++ b/sys/src/cmd/rio/xfid.c
@@ -247,6 +247,7 @@ xfidopen(Xfid *x)
 {
 	Fcall t;
 	Window *w;
+	char *s;
 
 	w = x->f->w;
 	if(w != nil && w->deleted){
@@ -312,8 +313,12 @@ xfidopen(Xfid *x)
 		}
 		break;
 	case Qtap:
-		chanprint(ctltap, "%c", Tapon);
-		break;
+		chanprint(ctltap, "%c%c", Tapon, x->mode);
+		s = recvp(resptap);
+		if(s == nil)
+			break;
+		filsysrespond(x->fs, x, &t, s);
+		return;
 	}
 	t.qid = x->f->qid;
 	t.iounit = messagesize-IOHDRSZ;
@@ -369,7 +374,8 @@ xfidclose(Xfid *x)
 			w->wctlopen = FALSE;
 		break;
 	case Qtap:
-		chanprint(ctltap, "%c", Tapoff);
+		chanprint(ctltap, "%c%c", Tapoff, x->f->mode);
+		recvp(resptap);
 		break;
 	}
 	if(w)
@@ -581,12 +587,18 @@ xfidwrite(Xfid *x)
 		}
 		e = x->data + cnt;
 		for(p = x->data; p < e; p += strlen(p)+1){
-			if(*p == '\0'){
+			switch(*p){
+			case '\0':
 				fc.count = p - x->data;
 				filsysrespond(x->fs, x, &fc, "null message type");
 				return;
+			case Tapfocus:
+				/* cleanup our own pollution */
+				break;
+			default:
+				chanprint(fromtap, "%s", p);
+				break;	
 			}
-			chanprint(fromtap, "%s", p);
 		}
 		break;