vireventthread: Introduce virEventThreadStop

The aim is to move parts of vir_event_thread_finalize() that MAY
block into a separate function, so that unrefing the a
virEventThread no longer blocks (or require releasing and
subsequent re-acquiring of a mutex).

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>

src/libvirt_private.syms

@@ -2288,6 +2288,7 @@ virEventGLibRunOnce;
 # util/vireventthread.h
 virEventThreadGetContext;
 virEventThreadNew;
+virEventThreadStop;
 
 
 # util/virfcp.h

src/util/vireventthread.c

@@ -188,6 +188,28 @@ virEventThreadNew(const char *name)
 }
 
 
+/**
+ * virEventThreadStop:
+ * @evt: event thread
+ *
+ * May block until all events are processed. Typical use case is:
+ *
+ * virEventThread *evt = virEventThreadNew("name");
+ * ...
+ * virEventThreadStop(evt);
+ * g_object_unref(evt);
+ */
+void
+virEventThreadStop(virEventThread *evt)
+{
+    if (evt->thread) {
+        g_main_loop_quit(evt->loop);
+        g_thread_join(evt->thread);
+        evt->thread = NULL;
+    }
+}
+
+
 GMainContext *
 virEventThreadGetContext(virEventThread *evt)
 {

src/util/vireventthread.h

@@ -28,4 +28,6 @@ G_DECLARE_FINAL_TYPE(virEventThread, vir_event_thread, VIR, EVENT_THREAD, GObjec
 
 virEventThread *virEventThreadNew(const char *name);
 
+void virEventThreadStop(virEventThread *evt);
+
 GMainContext *virEventThreadGetContext(virEventThread *evt);