ui/vnc: Introduce the VncWorker type

The worker thread copies data in VncState to avoid race, but some
data are too big to copy. Such data are held with pointers to avoid
the overhead to copy, but it requires tedious memory management and
makes them vulnerable to race.

Introduce the VncWorker type to contain all data shared without copying.
It allows allocating and freeing all shared data at once and shows that
the race with the worker thread needs to be taken care of when
accessing them.

Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20250603-zlib-v3-2-20b857bd8d05@rsg.ci.i.u-tokyo.ac.jp>

1 files changed, 4 insertions, 9 deletions

diff --git a/ui/vnc-jobs.c b/ui/vnc-jobs.c
index d3486af9e2..bed33950a8 100644
--- a/ui/vnc-jobs.c
+++ b/ui/vnc-jobs.c
@@ -185,14 +185,10 @@ static void vnc_async_encoding_start(VncState *orig, VncState *local)
     local->vnc_encoding = orig->vnc_encoding;
     local->features = orig->features;
     local->vd = orig->vd;
-    local->lossy_rect = orig->lossy_rect;
     local->write_pixels = orig->write_pixels;
     local->client_pf = orig->client_pf;
     local->client_endian = orig->client_endian;
-    local->tight = orig->tight;
-    local->zlib = orig->zlib;
     local->hextile = orig->hextile;
-    local->zrle = orig->zrle;
     local->client_width = orig->client_width;
     local->client_height = orig->client_height;
 }
@@ -200,11 +196,7 @@ static void vnc_async_encoding_start(VncState *orig, VncState *local)
 static void vnc_async_encoding_end(VncState *orig, VncState *local)
 {
     buffer_free(&local->output);
-    orig->tight = local->tight;
-    orig->zlib = local->zlib;
     orig->hextile = local->hextile;
-    orig->zrle = local->zrle;
-    orig->lossy_rect = local->lossy_rect;
 }
 
 static bool vnc_worker_clamp_rect(VncState *vs, VncJob *job, VncRect *rect)
@@ -237,6 +229,7 @@ static bool vnc_worker_clamp_rect(VncState *vs, VncJob *job, VncRect *rect)
 
 static int vnc_worker_thread_loop(VncJobQueue *queue)
 {
+    VncConnection *vc;
     VncJob *job;
     VncRectEntry *entry, *tmp;
     VncState vs = {};
@@ -256,6 +249,7 @@ static int vnc_worker_thread_loop(VncJobQueue *queue)
     }
 
     assert(job->vs->magic == VNC_MAGIC);
+    vc = container_of(job->vs, VncConnection, vs);
 
     vnc_lock_output(job->vs);
     if (job->vs->ioc == NULL || job->vs->abort == true) {
@@ -295,7 +289,8 @@ static int vnc_worker_thread_loop(VncJobQueue *queue)
         }
 
         if (vnc_worker_clamp_rect(&vs, job, &entry->rect)) {
-            n = vnc_send_framebuffer_update(&vs, entry->rect.x, entry->rect.y,
+            n = vnc_send_framebuffer_update(&vs, &vc->worker,
+                                            entry->rect.x, entry->rect.y,
                                             entry->rect.w, entry->rect.h);
 
             if (n >= 0) {