rio: preserve window z-order on resize, fix race conditions

sort the window array by w->topped before reshaping all
windows. this preserves the window z-order.

remove implicit focus change on reshape/move. it called
wcurrent() in wtcl thread which might send a wctl message
to itself, bad... also we might not want to change focus
on reshape, like for the rio resize. so we set the input
window explicitely in all call sites.

window deletion was racy. wclosewin() destroys w->i, but
it is called outside the wctl thread so it might just
free the image under libframe doing some text selection.
this is fixed the following: add wclunk() function,
which basically just marks the window as deleted and
removes the reference from the window[] and hidden[]
arrays. (called on wclose() when refcount drops to
zero). wclosewin() now just frees the image and is only
called from the wctl thread on exit or when handing
the Deleted message.

get a reference to the window when doing sweeping or
moving as the filesystem might just clunk it under
us and we might end up sending wctl messages to
a Exited window.

wctl resize message has to fail if the window is not
current as it might be hidden... would also be annoying.

1 files changed, 59 insertions, 53 deletions

diff --git a/sys/src/cmd/rio/wctl.c b/sys/src/cmd/rio/wctl.c
index 2e91b0e7c..557e9e84d 100644
--- a/sys/src/cmd/rio/wctl.c
+++ b/sys/src/cmd/rio/wctl.c
@@ -346,68 +346,32 @@ wctlnew(Rectangle rect, char *arg, int pid, int hideit, int scrollit, char *dir,
 }
 
 int
-writewctl(Xfid *x, char *err)
+wctlcmd(Window *w, Rectangle r, int cmd, char *err)
 {
-	int cnt, cmd, j, id, hideit, scrollit, pid;
 	Image *i;
-	char *arg, *dir;
-	Rectangle rect;
-	Window *w;
-
-	w = x->f->w;
-	cnt = x->count;
-	x->data[cnt] = '\0';
-	id = 0;
-
-	rect = rectsubpt(w->screenr, screen->r.min);
-	cmd = parsewctl(&arg, rect, &rect, &pid, &id, &hideit, &scrollit, &dir, x->data, err);
-	if(cmd < 0)
-		return -1;
-
-	if(mouse->buttons!=0 && cmd>=Top){
-		strcpy(err, "action disallowed when mouse active");
-		return -1;
-	}
-
-	if(id != 0){
-		for(j=0; j<nwindow; j++)
-			if(window[j]->id == id)
-				break;
-		if(j == nwindow){
-			strcpy(err, "no such window id");
-			return -1;
-		}
-		w = window[j];
-		if(w->deleted || w->i==nil){
-			strcpy(err, "window deleted");
-			return -1;
-		}
-	}
 
 	switch(cmd){
-	case New:
-		return wctlnew(rect, arg, pid, hideit, scrollit, dir, err);
-	case Set:
-		if(pid > 0)
-			wsetpid(w, pid, 0);
-		return 1;
 	case Move:
-		rect = Rect(rect.min.x, rect.min.y, rect.min.x+Dx(w->screenr), rect.min.y+Dy(w->screenr));
-		rect = rectonscreen(rect);
+		r = Rect(r.min.x, r.min.y, r.min.x+Dx(w->screenr), r.min.y+Dy(w->screenr));
+		r = rectonscreen(r);
 		/* fall through */
 	case Resize:
-		if(!goodrect(rect)){
+		if(!goodrect(r)){
 			strcpy(err, Ebadwr);
 			return -1;
 		}
-		if(eqrect(rect, w->screenr))
+		if(w != input){
+			strcpy(err, "window not current");
+			return -1;
+		}
+		if(eqrect(r, w->screenr))
 			return 1;
-		i = allocwindow(wscreen, rect, Refbackup, DWhite);
+		i = allocwindow(wscreen, r, Refbackup, DWhite);
 		if(i == nil){
 			strcpy(err, Ewalloc);
 			return -1;
 		}
-		border(i, rect, Selborder, red, ZP);
+		border(i, r, Selborder, red, ZP);
 		wsendctlmesg(w, Reshaped, i->r, i);
 		return 1;
 	case Scroll:
@@ -441,26 +405,68 @@ writewctl(Xfid *x, char *err)
 		}
 		return 1;
 	case Unhide:
-		for(j=0; j<nhidden; j++)
-			if(hidden[j] == w)
-				break;
-		if(j == nhidden){
+		switch(wunhide(w)){
+		case -1:
 			strcpy(err, "window not hidden");
 			return -1;
-		}
-		if(wunhide(j) == 0){
+		case 0:
 			strcpy(err, "hide failed");
 			return -1;
+		default:
+			break;
 		}
 		return 1;
 	case Delete:
 		wsendctlmesg(w, Deleted, ZR, nil);
 		return 1;
 	}
+
 	strcpy(err, "invalid wctl message");
 	return -1;
 }
 
+int
+writewctl(Xfid *x, char *err)
+{
+	int cnt, cmd, id, hideit, scrollit, pid;
+	char *arg, *dir;
+	Rectangle r;
+	Window *w;
+
+	w = x->f->w;
+	cnt = x->count;
+	x->data[cnt] = '\0';
+	id = 0;
+
+	r = rectsubpt(w->screenr, screen->r.min);
+	cmd = parsewctl(&arg, r, &r, &pid, &id, &hideit, &scrollit, &dir, x->data, err);
+	if(cmd < 0)
+		return -1;
+
+	if(id != 0){
+		w = wlookid(id);
+		if(w == 0){
+			strcpy(err, "no such window id");
+			return -1;
+		}
+	}
+
+	switch(cmd){
+	case New:
+		return wctlnew(r, arg, pid, hideit, scrollit, dir, err);
+	case Set:
+		if(pid > 0)
+			wsetpid(w, pid, 0);
+		return 1;
+	}
+
+	incref(w);
+	id = wctlcmd(w, r, cmd, err);
+	wclose(w);
+
+	return id;
+}
+
 void
 wctlthread(void *v)
 {