remote: Use virDomainEventState helpers

One functionality change here is that we no longer force enable the event
timeout for every queued event, only enable it for the first event after
the queue has been flushed. This is how other drivers have already done it,
and I haven't encountered problems in practice.

v3:
    Adjust for new virDomainEventStateNew argument

src/remote/remote_driver.c

@@ -184,15 +184,7 @@ struct private_data {
     unsigned int bufferLength;
     unsigned int bufferOffset;
 
-    /* The list of domain event callbacks */
-    virDomainEventCallbackListPtr callbackList;
-    /* The queue of domain events generated
-       during a call / response rpc          */
-    virDomainEventQueuePtr domainEvents;
-    /* Timer for flushing domainEvents queue */
-    int eventFlushTimer;
-    /* Flag if we're in process of dispatching */
-    int domainEventDispatching;
+    virDomainEventStatePtr domainEventState;
 
     /* Self-pipe to wakeup threads waiting in poll() */
     int wakeupSendFD;
@@ -264,6 +256,7 @@ static void make_nonnull_nwfilter (remote_nonnull_nwfilter *nwfilter_dst, virNWF
 static void make_nonnull_domain_snapshot (remote_nonnull_domain_snapshot *snapshot_dst, virDomainSnapshotPtr snapshot_src);
 void remoteDomainEventFired(int watch, int fd, int event, void *data);
 void remoteDomainEventQueueFlush(int timer, void *opaque);
+void remoteDomainEventQueue(struct private_data *priv, virDomainEventPtr event);
 /*----------------------------------------------------------------------*/
 
 /* Helper functions for remoteOpen. */
@@ -913,17 +906,6 @@ doRemoteOpen (virConnectPtr conn,
         }
     }
 
-    if(VIR_ALLOC(priv->callbackList)<0) {
-        virReportOOMError();
-        goto failed;
-    }
-
-    if(VIR_ALLOC(priv->domainEvents)<0) {
-        virReportOOMError();
-        goto failed;
-    }
-
-    VIR_DEBUG("Adding Handler for remote events");
     /* Set up a callback to listen on the socket data */
     if ((priv->watch = virEventAddHandle(priv->sock,
                                          VIR_EVENT_HANDLE_READABLE,
@@ -931,18 +913,21 @@ doRemoteOpen (virConnectPtr conn,
                                          conn, NULL)) < 0) {
         VIR_DEBUG("virEventAddHandle failed: No addHandleImpl defined."
                " continuing without events.");
-    } else {
+        priv->watch = -1;
+    }
 
-        VIR_DEBUG("Adding Timeout for remote event queue flushing");
-        if ( (priv->eventFlushTimer = virEventAddTimeout(-1,
-                                                         remoteDomainEventQueueFlush,
-                                                         conn, NULL)) < 0) {
-            VIR_DEBUG("virEventAddTimeout failed: No addTimeoutImpl defined. "
-                    "continuing without events.");
-            virEventRemoveHandle(priv->watch);
-            priv->watch = -1;
-        }
+    priv->domainEventState = virDomainEventStateNew(remoteDomainEventQueueFlush,
+                                                    conn,
+                                                    NULL,
+                                                    false);
+    if (!priv->domainEventState) {
+        goto failed;
+    }
+    if (priv->domainEventState->timer < 0 && priv->watch != -1) {
+        virEventRemoveHandle(priv->watch);
+        priv->watch = -1;
     }
+
     /* Successful. */
     retcode = VIR_DRV_OPEN_SUCCESS;
 
@@ -1559,12 +1544,13 @@ verify_certificate (virConnectPtr conn ATTRIBUTE_UNUSED,
 static int
 doRemoteClose (virConnectPtr conn, struct private_data *priv)
 {
-    if (priv->eventFlushTimer >= 0) {
-        /* Remove timeout */
-        virEventRemoveTimeout(priv->eventFlushTimer);
-        /* Remove handle for remote events */
+    /* Remove timer before closing the connection, to avoid possible
+     * remoteDomainEventFired with a free'd connection */
+    if (priv->domainEventState->timer >= 0) {
+        virEventRemoveTimeout(priv->domainEventState->timer);
         virEventRemoveHandle(priv->watch);
         priv->watch = -1;
+        priv->domainEventState->timer = -1;
     }
 
     if (call (conn, priv, 0, REMOTE_PROC_CLOSE,
@@ -1605,11 +1591,7 @@ retry:
     /* See comment for remoteType. */
     VIR_FREE(priv->type);
 
-    /* Free callback list */
-    virDomainEventCallbackListFree(priv->callbackList);
-
-    /* Free queued events */
-    virDomainEventQueueFree(priv->domainEvents);
+    virDomainEventStateFree(priv->domainEventState);
 
     return 0;
 }
@@ -3800,17 +3782,20 @@ static int remoteDomainEventRegister(virConnectPtr conn,
 
     remoteDriverLock(priv);
 
-    if (priv->eventFlushTimer < 0) {
+    if (priv->domainEventState->timer < 0) {
          remoteError(VIR_ERR_NO_SUPPORT, "%s", _("no event support"));
          goto done;
     }
-    if (virDomainEventCallbackListAdd(conn, priv->callbackList,
+
+    if (virDomainEventCallbackListAdd(conn, priv->domainEventState->callbacks,
                                       callback, opaque, freecb) < 0) {
          remoteError(VIR_ERR_RPC, "%s", _("adding cb to list"));
          goto done;
     }
 
-    if (virDomainEventCallbackListCountID(conn, priv->callbackList, VIR_DOMAIN_EVENT_ID_LIFECYCLE) == 1) {
+    if (virDomainEventCallbackListCountID(conn,
+                                          priv->domainEventState->callbacks,
+                                          VIR_DOMAIN_EVENT_ID_LIFECYCLE) == 1) {
         /* Tell the server when we are the first callback deregistering */
         if (call (conn, priv, 0, REMOTE_PROC_DOMAIN_EVENTS_REGISTER,
                 (xdrproc_t) xdr_void, (char *) NULL,
@@ -3833,21 +3818,14 @@ static int remoteDomainEventDeregister(virConnectPtr conn,
 
     remoteDriverLock(priv);
 
-    if (priv->domainEventDispatching) {
-        if (virDomainEventCallbackListMarkDelete(conn, priv->callbackList,
-                                                 callback) < 0) {
-            remoteError(VIR_ERR_RPC, "%s", _("marking cb for deletion"));
-            goto done;
-        }
-    } else {
-        if (virDomainEventCallbackListRemove(conn, priv->callbackList,
-                                             callback) < 0) {
-            remoteError(VIR_ERR_RPC, "%s", _("removing cb from list"));
-            goto done;
-        }
-    }
+    if (virDomainEventStateDeregister(conn,
+                                      priv->domainEventState,
+                                      callback) < 0)
+        goto done;
 
-    if (virDomainEventCallbackListCountID(conn, priv->callbackList, VIR_DOMAIN_EVENT_ID_LIFECYCLE) == 0) {
+    if (virDomainEventCallbackListCountID(conn,
+                                          priv->domainEventState->callbacks,
+                                          VIR_DOMAIN_EVENT_ID_LIFECYCLE) == 0) {
         /* Tell the server when we are the last callback deregistering */
         if (call (conn, priv, 0, REMOTE_PROC_DOMAIN_EVENTS_DEREGISTER,
                   (xdrproc_t) xdr_void, (char *) NULL,
@@ -4723,12 +4701,13 @@ static int remoteDomainEventRegisterAny(virConnectPtr conn,
 
     remoteDriverLock(priv);
 
-    if (priv->eventFlushTimer < 0) {
+    if (priv->domainEventState->timer < 0) {
          remoteError(VIR_ERR_NO_SUPPORT, "%s", _("no event support"));
          goto done;
     }
 
-    if ((callbackID = virDomainEventCallbackListAddID(conn, priv->callbackList,
+    if ((callbackID = virDomainEventCallbackListAddID(conn,
+                                                      priv->domainEventState->callbacks,
                                                       dom, eventID,
                                                       callback, opaque, freecb)) < 0) {
          remoteError(VIR_ERR_RPC, "%s", _("adding cb to list"));
@@ -4737,13 +4716,17 @@ static int remoteDomainEventRegisterAny(virConnectPtr conn,
 
     /* If this is the first callback for this eventID, we need to enable
      * events on the server */
-    if (virDomainEventCallbackListCountID(conn, priv->callbackList, eventID) == 1) {
+    if (virDomainEventCallbackListCountID(conn,
+                                          priv->domainEventState->callbacks,
+                                          eventID) == 1) {
         args.eventID = eventID;
 
         if (call (conn, priv, 0, REMOTE_PROC_DOMAIN_EVENTS_REGISTER_ANY,
                   (xdrproc_t) xdr_remote_domain_events_register_any_args, (char *) &args,
                   (xdrproc_t) xdr_void, (char *)NULL) == -1) {
-            virDomainEventCallbackListRemoveID(conn, priv->callbackList, callbackID);
+            virDomainEventCallbackListRemoveID(conn,
+                                               priv->domainEventState->callbacks,
+                                               callbackID);
             goto done;
         }
     }
@@ -4766,28 +4749,23 @@ static int remoteDomainEventDeregisterAny(virConnectPtr conn,
 
     remoteDriverLock(priv);
 
-    if ((eventID = virDomainEventCallbackListEventID(conn, priv->callbackList, callbackID)) < 0) {
+    if ((eventID = virDomainEventCallbackListEventID(conn,
+                                                     priv->domainEventState->callbacks,
+                                                     callbackID)) < 0) {
         remoteError(VIR_ERR_RPC, _("unable to find callback ID %d"), callbackID);
         goto done;
     }
 
-    if (priv->domainEventDispatching) {
-        if (virDomainEventCallbackListMarkDeleteID(conn, priv->callbackList,
-                                                   callbackID) < 0) {
-            remoteError(VIR_ERR_RPC, "%s", _("marking cb for deletion"));
-            goto done;
-        }
-    } else {
-        if (virDomainEventCallbackListRemoveID(conn, priv->callbackList,
-                                               callbackID) < 0) {
-            remoteError(VIR_ERR_RPC, "%s", _("removing cb from list"));
-            goto done;
-        }
-    }
+    if (virDomainEventStateDeregisterAny(conn,
+                                         priv->domainEventState,
+                                         callbackID) < 0)
+        goto done;
 
     /* If that was the last callback for this eventID, we need to disable
      * events on the server */
-    if (virDomainEventCallbackListCountID(conn, priv->callbackList, eventID) == 0) {
+    if (virDomainEventCallbackListCountID(conn,
+                                          priv->domainEventState->callbacks,
+                                          eventID) == 0) {
         args.eventID = eventID;
 
         if (call (conn, priv, 0, REMOTE_PROC_DOMAIN_EVENTS_DEREGISTER_ANY,
@@ -5593,13 +5571,7 @@ processCallDispatchMessage(virConnectPtr conn, struct private_data *priv,
     if (!event)
         return -1;
 
-    if (virDomainEventQueuePush(priv->domainEvents,
-                                event) < 0) {
-        VIR_DEBUG("Error adding event to queue");
-        virDomainEventFree(event);
-    }
-    virEventUpdateTimeout(priv->eventFlushTimer, 0);
-
+    remoteDomainEventQueue(priv, event);
     return 0;
 }
 
@@ -6270,31 +6242,22 @@ remoteDomainEventQueueFlush(int timer ATTRIBUTE_UNUSED, void *opaque)
 {
     virConnectPtr conn = opaque;
     struct private_data *priv = conn->privateData;
-    virDomainEventQueue tempQueue;
 
-    remoteDriverLock(priv);
 
+    remoteDriverLock(priv);
     VIR_DEBUG("Event queue flush %p", conn);
-    priv->domainEventDispatching = 1;
-
-    /* Copy the queue, so we're reentrant safe */
-    tempQueue.count = priv->domainEvents->count;
-    tempQueue.events = priv->domainEvents->events;
-    priv->domainEvents->count = 0;
-    priv->domainEvents->events = NULL;
-
-    virEventUpdateTimeout(priv->eventFlushTimer, -1);
-    virDomainEventQueueDispatch(&tempQueue, priv->callbackList,
-                                remoteDomainEventDispatchFunc, priv);
-
-    /* Purge any deleted callbacks */
-    virDomainEventCallbackListPurgeMarked(priv->callbackList);
-
-    priv->domainEventDispatching = 0;
 
+    virDomainEventStateFlush(priv->domainEventState,
+                             remoteDomainEventDispatchFunc,
+                             priv);
     remoteDriverUnlock(priv);
 }
 
+void
+remoteDomainEventQueue(struct private_data *priv, virDomainEventPtr event)
+{
+    virDomainEventStateQueue(priv->domainEventState, event);
+}
 
 /* get_nonnull_domain and get_nonnull_network turn an on-wire
  * (name, uuid) pair into virDomainPtr or virNetworkPtr object.