GUACAMOLE-377: Migrate VNC to default render loop.

src/protocols/vnc/client.h

@@ -23,29 +23,14 @@
 #include <guacamole/client.h>
 
 /**
- * The maximum duration of a frame in milliseconds. This ensures we at least
- * meet a reasonable minimum framerate in the case that the VNC server provides
- * no frame boundaries and streams data continuously enough that frame
- * boundaries are not discernable through timing.
+ * The amount of time to wait for new messages from the VNC server before
+ * moving on to internal matters, in milliseconds. This value must be kept
+ * reasonably small such that a slow VNC server will not prevent external
+ * events from being handled (such as the stop signal from guac_client_stop()),
+ * but large enough that the message handling loop does not eat up CPU
+ * spinning.
  */
-#define GUAC_VNC_MAX_FRAME_DURATION 33
-
-/**
- * The minimum duration of a frame in milliseconds. This ensures we don't start
- * flushing a ton of tiny frames if an VNC server provides no frame boundaries
- * and streams data inconsistently enough that timing would suggest frame
- * boundaries in the middle of a frame.
- */
-#define GUAC_VNC_MIN_FRAME_DURATION 10
-
-/**
- * The amount of time to wait for a new message from the VNC server when
- * beginning a new frame, in milliseconds. This value must be kept reasonably
- * small such that a slow VNC server will not prevent external events from
- * being handled (such as the stop signal from guac_client_stop()), but large
- * enough that the message handling loop does not eat up CPU spinning.
- */
-#define GUAC_VNC_FRAME_START_TIMEOUT 1000
+#define GUAC_VNC_MESSAGE_CHECK_INTERVAL 1000
 
 /**
  * The number of milliseconds to wait between connection attempts.

src/protocols/vnc/cursor.c

@@ -114,6 +114,7 @@ void guac_vnc_cursor(rfbClient* client, int x, int y, int w, int h, int vnc_bpp)
 
     /* Draw operation is now complete */
     guac_display_layer_close_raw(cursor_layer, context);
+    guac_display_render_thread_notify_modified(vnc_client->render_thread);
 
     /* libvncclient does not free rcMask as it does rcSource */
     if (client->rcMask != NULL) {

src/protocols/vnc/display.c

@@ -129,6 +129,8 @@ void guac_vnc_update(rfbClient* client, int x, int y, int w, int h) {
         vnc_client->copy_rect_used = 0;
     }
 
+    guac_display_render_thread_notify_modified(vnc_client->render_thread);
+
 }
 
 void guac_vnc_copyrect(rfbClient* client, int src_x, int src_y, int w, int h, int dest_x, int dest_y) {

src/protocols/vnc/vnc.c

@@ -596,44 +596,22 @@ void* guac_vnc_client_thread(void* data) {
 
     guac_display_end_frame(vnc_client->display);
 
+    vnc_client->render_thread = guac_display_render_thread_create(vnc_client->display);
+
     /* Handle messages from VNC server while client is running */
     while (client->state == GUAC_CLIENT_RUNNING) {
 
         /* Wait for data and construct a reasonable frame */
-        int wait_result = guac_vnc_wait_for_messages(rfb_client, GUAC_VNC_FRAME_START_TIMEOUT);
+        int wait_result = guac_vnc_wait_for_messages(rfb_client, GUAC_VNC_MESSAGE_CHECK_INTERVAL);
         if (wait_result > 0) {
 
-            /* Read server messages until frame is built */
-            guac_timestamp frame_start = guac_timestamp_current();
-            do {
-
-                /* Handle any message received */
-                if (!guac_vnc_handle_messages(vnc_client)) {
-                    guac_client_abort(client,
-                            GUAC_PROTOCOL_STATUS_UPSTREAM_ERROR,
-                            "Error handling message from VNC server.");
-                    break;
-                }
-
-                int frame_duration = guac_timestamp_current() - frame_start;
-
-                /* Continue processing messages for up to a reasonable minimum
-                 * framerate without an explicit frame boundary indicating that
-                 * the frame is not yet complete */
-                if (frame_duration > GUAC_VNC_MAX_FRAME_DURATION)
-                    break;
-
-                /* Do not exceed a reasonable maximum framerate without an
-                 * explicit frame boundary terminating the frame early */
-                int allowed_wait = GUAC_VNC_MIN_FRAME_DURATION - frame_duration;
-                if (allowed_wait < 0)
-                    allowed_wait = 0;
-
-                wait_result = guac_vnc_wait_for_messages(rfb_client, allowed_wait);
-
-            } while (wait_result > 0);
-
-            guac_display_end_frame(vnc_client->display);
+            /* Handle any message received */
+            if (!guac_vnc_handle_messages(vnc_client)) {
+                guac_client_abort(client,
+                        GUAC_PROTOCOL_STATUS_UPSTREAM_ERROR,
+                        "Error handling message from VNC server.");
+                break;
+            }
 
         }
 
@@ -643,6 +621,10 @@ void* guac_vnc_client_thread(void* data) {
 
     }
 
+    /* Stop render loop */
+    guac_display_render_thread_destroy(vnc_client->render_thread);
+    vnc_client->render_thread = NULL;
+
     /* Kill client and finish connection */
     guac_client_stop(client);
     guac_client_log(client, GUAC_LOG_INFO, "Internal VNC client disconnected");

src/protocols/vnc/vnc.h

@@ -113,6 +113,12 @@ typedef struct guac_vnc_client {
      */
     guac_display_layer_raw_context* current_context;
 
+    /**
+     * The current instance of the guac_display render thread. If the thread
+     * has not yet been started, this will be NULL.
+     */
+    guac_display_render_thread* render_thread;
+
     /**
      * Internal clipboard.
      */