[Qemu-devel] [PATCH 07/12] BACKPORT: vnc: fix copyrect screen corruption

[Glauber Costa <glommer@redhat.com>]

From: Gerd Hoffmann <kraxel@redhat.com>

When sending a copyrect command to the vnc client, we must also update
the local server surface.  Otherwise the server's and the client's idea
of the screen content run out of sync and screen updates don't work
correctly.

[ backport: uses ds_get_data() instead of direct dereference ]
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 vnc.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/vnc.c b/vnc.c
index 1d8ebe7..c0700c0 100644
--- a/vnc.c
+++ b/vnc.c
@@ -633,8 +633,14 @@ static void send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
 
 static void vnc_copy(VncState *vs, int src_x, int src_y, int dst_x, int dst_y, int w, int h)
 {
+
+    uint8_t *src_row;
+    uint8_t *dst_row;
+    int y,pitch,depth;
+
     vnc_update_client(vs);
 
+    /* send bitblit op to the vnc client */
     vnc_write_u8(vs, 0);  /* msg id */
     vnc_write_u8(vs, 0);
     vnc_write_u16(vs, 1); /* number of rects */
@@ -642,6 +648,23 @@ static void vnc_copy(VncState *vs, int src_x, int src_y, int dst_x, int dst_y, i
     vnc_write_u16(vs, src_x);
     vnc_write_u16(vs, src_y);
     vnc_flush(vs);
+
+    /* do bitblit op on the local surface too */
+    pitch = ds_get_linesize(vs->ds);
+    depth = ds_get_bytes_per_pixel(vs->ds);
+    src_row = ds_get_data(vs->ds) + pitch * src_y + depth * src_x;
+    dst_row = ds_get_data(vs->ds) + pitch * dst_y + depth * dst_x;
+    if (dst_y > src_y) {
+        /* copy backwards */
+        src_row += pitch * (h-1);
+        dst_row += pitch * (h-1);
+        pitch = -pitch;
+    }
+    for (y = 0; y < h; y++) {
+        memmove(dst_row, src_row, w * depth);
+        src_row += pitch;
+        dst_row += pitch;
+    }
 }
 
 static void vnc_dpy_copy(DisplayState *ds, int src_x, int src_y, int dst_x, int dst_y, int w, int h)
-- 
1.6.2.2