JBR-5900: Fix deadlock when enabling the Wakefield extensionjb21-b201

1 files changed, 18 insertions, 28 deletions

diff --git a/src/java.desktop/unix/native/libawt_wlawt/WLToolkit.c b/src/java.desktop/unix/native/libawt_wlawt/WLToolkit.c
index aad5383f9d7..9209103e114 100644
--- a/src/java.desktop/unix/native/libawt_wlawt/WLToolkit.c
+++ b/src/java.desktop/unix/native/libawt_wlawt/WLToolkit.c
@@ -927,26 +927,6 @@ wl_display_poll(struct wl_display *display, int events, int poll_timeout)
     return rc;
 }
 
-static void
-dispatch_nondefault_queues(JNIEnv *env)
-{
-    // The handlers of the events on these queues will be called from here, i.e. on
-    // the 'AWT-Wayland' (toolkit) thread. The handlers must *not* execute any
-    // arbitrary user code that can block.
-    int rc = 0;
-
-#ifdef WAKEFIELD_ROBOT
-    if (robot_queue) {
-        rc = wl_display_dispatch_queue_pending(wl_display, robot_queue);
-    }
-#endif
-
-    if (rc < 0) {
-        JNU_ThrowByName(env, "java/awt/AWTError", "Wayland error during events processing");
-        return;
-    }
-}
-
 int
 wl_flush_to_server(JNIEnv *env)
 {
@@ -985,21 +965,31 @@ JNIEXPORT void JNICALL
 Java_sun_awt_wl_WLToolkit_dispatchNonDefaultQueuesImpl
   (JNIEnv *env, jobject obj)
 {
-    int rc = 0;
-    while (rc != -1) {
 #ifdef WAKEFIELD_ROBOT
-        if (robot_queue) {
-            rc = wl_display_dispatch_queue(wl_display, robot_queue);
-        } else {
+    if (!robot_queue) {
+        return;
+    }
+
+    int rc = 0;
+
+    while (rc >= 0) {
+        // Dispatch pending events on the wakefield queue
+        while (wl_display_prepare_read_queue(wl_display, robot_queue) != 0 && rc >= 0) {
+            rc = wl_display_dispatch_queue_pending(wl_display, robot_queue);
+        }
+        if (rc < 0) {
+            wl_display_cancel_read(wl_display);
             break;
         }
-#else
-    break;
-#endif
+
+        // Wait for new events, wl_display_read_events is a synchronization point between all threads reading events.
+        rc = wl_display_read_events(wl_display);
     }
+
     // Simply return in case of any error; the actual error reporting (exception)
     // and/or shutdown will happen on the "main" toolkit thread AWT-Wayland,
     // see readEvents() below.
+#endif
 }
 
 JNIEXPORT jint JNICALL