devdraw: get rid of softscreen==0xa110c hack and make attachscreen() return Memdata*

all screen implementations use a Memimage* internally
for the framebuffer, so we can return a shared reference
to its Memdata structure in attachscreen() instead of
a framebuffer data pointer.

this eleminates the softscreen == 0xa110c hack as we
always use shared Memdata* now.

3 files changed, 9 insertions, 27 deletions

diff --git a/sys/src/cmd/vnc/devdraw.c b/sys/src/cmd/vnc/devdraw.c
index 07d27c147..48ec63e03 100644
--- a/sys/src/cmd/vnc/devdraw.c
+++ b/sys/src/cmd/vnc/devdraw.c
@@ -925,33 +925,14 @@ makescreenimage(void)
 	Memdata *md;
 	Memimage *i;
 	Rectangle r;
-	uchar *data;
 
-	if((data = attachscreen(&r, &chan, &depth, &width, &sdraw.softscreen)) == nil)
+	if((md = attachscreen(&r, &chan, &depth, &width, &sdraw.softscreen)) == nil)
 		return nil;
-	if(sdraw.softscreen == 0xa110c){
-		/* hack: softscreen is memimage. */
-		md = *((Memdata**)(data - sizeof(ulong) - sizeof(Memdata*)));
-
-		assert(md->bdata == data);
-		assert(md->ref > 1);
-		assert(md->allocd);
-
-		if((i = allocmemimaged(r, chan, md)) == nil){
-			md->ref--;
-			return nil;
-		}
-	}else{
-		if((md = malloc(sizeof *md)) == nil)
-			return nil;
-		md->allocd = 1;
-		md->base = nil;
-		md->bdata = data;
-		md->ref = 1;
-		if((i = allocmemimaged(r, chan, md)) == nil){
+	assert(md->ref > 0);
+	if((i = allocmemimaged(r, chan, md)) == nil){
+		if(--md->ref == 0 && md->allocd)
 			free(md);
-			return nil;
-		}
+		return nil;
 	}
 	i->width = width;
 	i->clipr = r;
diff --git a/sys/src/cmd/vnc/screen.c b/sys/src/cmd/vnc/screen.c
index 6d507877c..51361584d 100644
--- a/sys/src/cmd/vnc/screen.c
+++ b/sys/src/cmd/vnc/screen.c
@@ -126,7 +126,7 @@ screenwin(void)
 	qunlock(&drawlock);
 }
 
-uchar*
+Memdata*
 attachscreen(Rectangle* r, ulong* chan, int* d, int* width, int *softscreen)
 {
 	*r = gscreen->clipr;
@@ -135,7 +135,8 @@ attachscreen(Rectangle* r, ulong* chan, int* d, int* width, int *softscreen)
 	*width = gscreen->width;
 	*softscreen = 1;
 
-	return gscreen->data->bdata;
+	gscreen->data->ref++;
+	return gscreen->data;
 }
 
 void
diff --git a/sys/src/cmd/vnc/screen.h b/sys/src/cmd/vnc/screen.h
index ce525102c..5ba53a9ac 100644
--- a/sys/src/cmd/vnc/screen.h
+++ b/sys/src/cmd/vnc/screen.h
@@ -29,7 +29,7 @@ extern void	blankscreen(int);
 void		screeninit(int x, int y, char *chanstr);
 void		screenwin(void);
 void		absmousetrack(int x, int y, int b, ulong msec);
-uchar		*attachscreen(Rectangle*, ulong*, int*, int*, int*);
+Memdata*	attachscreen(Rectangle*, ulong*, int*, int*, int*);
 void		deletescreenimage(void);
 void		resetscreenimage(void);