2 files changed, 122 insertions, 50 deletions
diff --git a/src/vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/JVppRegistryImpl.java b/src/vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/JVppRegistryImpl.java
index 6e938ae313f..baef14c3865 100644
--- a/src/vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/JVppRegistryImpl.java
+++ b/src/vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/JVppRegistryImpl.java
@@ -99,15 +99,24 @@ public final class JVppRegistryImpl implements JVppRegistry, ControlPingCallback
         final ControlPingCallback callback = (ControlPingCallback) pluginRegistry.get(clazz.getName());
         assertPluginWasRegistered(name, callback);
 
+        // controlPing0 is sending function and can go to waiting in case of e. g. full queue
+        // because of that it cant be in same synchronization block as used by reply handler function
+        int context = controlPing0();
+        if (context < 0) {
+            throw new VppInvocationException("controlPing", context);
+        }
+
         synchronized (pingCalls) {
-            int context = controlPing0();
-            if (context < 0) {
-                throw new VppInvocationException("controlPing", context);
+            // if callback is in map it's because reply was already received
+            EarlyControlPingReply earlyReplyCallback = (EarlyControlPingReply) pingCalls.remove(context);
+            if(earlyReplyCallback == null) {
+                pingCalls.put(context, callback);
+            } else {
+                callback.onControlPingReply(earlyReplyCallback.getReply());
             }
-
-            pingCalls.put(context, callback);
-            return context;
         }
+
+        return context;
     }
 
     @Override
@@ -116,8 +125,9 @@ public final class JVppRegistryImpl implements JVppRegistry, ControlPingCallback
         synchronized (pingCalls) {
             callback = pingCalls.remove(reply.context);
             if (callback == null) {
-                LOG.log(Level.WARNING, "No callback was registered for reply context=" + reply.context + " Contexts waiting="
-                    + pingCalls.keySet());
+                // reply received early, because we don't know callback to call
+                // we wrap the reply and let the sender to call it
+                pingCalls.put(reply.context, new EarlyControlPingReply(reply));
                 return;
             }
         }
@@ -151,4 +161,27 @@ public final class JVppRegistryImpl implements JVppRegistry, ControlPingCallback
     public void close() throws Exception {
         connection.close();
     }
+
+    private static class EarlyControlPingReply implements ControlPingCallback {
+
+        private final ControlPingReply reply;
+
+        public EarlyControlPingReply(final ControlPingReply reply) {
+            this.reply = reply;
+        }
+
+        public ControlPingReply getReply() {
+            return reply;
+        }
+
+        @Override
+        public void onError(VppCallbackException ex) {
+            throw new IllegalStateException("Calling onError in EarlyControlPingReply");
+        }
+
+        @Override
+        public void onControlPingReply(ControlPingReply reply) {
+            throw new IllegalStateException("Calling onControlPingReply in EarlyControlPingReply");
+        }
+    }
 }
diff --git a/src/vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/future/AbstractFutureJVppInvoker.java b/src/vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/future/AbstractFutureJVppInvoker.java
index e7df528ae30..ac85f5309ec 100644
--- a/src/vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/future/AbstractFutureJVppInvoker.java
+++ b/src/vpp-api/java/jvpp-registry/io/fd/vpp/jvpp/future/AbstractFutureJVppInvoker.java
@@ -21,6 +21,7 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
+
 import io.fd.vpp.jvpp.JVpp;
 import io.fd.vpp.jvpp.JVppRegistry;
 import io.fd.vpp.jvpp.VppInvocationException;
@@ -62,27 +63,41 @@ public abstract class AbstractFutureJVppInvoker implements FutureJVppInvoker {
     @Override
     @SuppressWarnings("unchecked")
     public <REQ extends JVppRequest, REPLY extends JVppReply<REQ>> CompletionStage<REPLY> send(REQ req) {
-        synchronized(requests) {
-            try {
-                final CompletableFuture<REPLY> replyCompletableFuture;
-                final int contextId = jvpp.send(req);
+        try {
+            // jvpp.send() can go to waiting state if sending queue is full, putting it into same
+            // synchronization block as used by receiving part (synchronized(requests)) can lead
+            // to deadlock between these two sides or at least slowing sending process by slow
+            // reader
+            final CompletableFuture<REPLY> replyCompletableFuture;
+            final int contextId = jvpp.send(req);
+
+            if(req instanceof JVppDump) {
+                throw new IllegalArgumentException("Send with empty reply dump has to be used in case of dump calls");
+            }
 
-                if(req instanceof JVppDump) {
-                    throw new IllegalArgumentException("Send with empty reply dump has to be used in case of dump calls");
+            synchronized(requests) {
+                CompletableFuture<? extends JVppReply<?>> replyFuture = requests.get(contextId);
+                if (replyFuture == null) {
+                    // reply not yet received, put new future into map
+                    replyCompletableFuture = new CompletableFuture<>();
+                    requests.put(contextId, replyCompletableFuture);
+                } else {
+                    // reply already received (should be completed by reader),
+                    // remove future from map and return it to caller
+                    replyCompletableFuture = (CompletableFuture<REPLY>) replyFuture;
+                    requests.remove(contextId);
                 }
-                replyCompletableFuture = new CompletableFuture<>();
-                requests.put(contextId, replyCompletableFuture);
-
-                // TODO in case of timeouts/missing replies, requests from the map are not removed
-                // consider adding cancel method, that would remove requests from the map and cancel
-                // associated replyCompletableFuture
-
-                return replyCompletableFuture;
-            } catch (VppInvocationException ex) {
-                final CompletableFuture<REPLY> replyCompletableFuture = new CompletableFuture<>();
-                replyCompletableFuture.completeExceptionally(ex);
-                return replyCompletableFuture;
             }
+
+            // TODO in case of timeouts/missing replies, requests from the map are not removed
+            // consider adding cancel method, that would remove requests from the map and cancel
+            // associated replyCompletableFuture
+
+            return replyCompletableFuture;
+        } catch (VppInvocationException ex) {
+            final CompletableFuture<REPLY> replyCompletableFuture = new CompletableFuture<>();
+            replyCompletableFuture.completeExceptionally(ex);
+            return replyCompletableFuture;
         }
     }
 
@@ -90,30 +105,54 @@ public abstract class AbstractFutureJVppInvoker implements FutureJVppInvoker {
     @SuppressWarnings("unchecked")
     public <REQ extends JVppRequest, REPLY extends JVppReply<REQ>, DUMP extends JVppReplyDump<REQ, REPLY>> CompletionStage<DUMP> send(
             REQ req, DUMP emptyReplyDump) {
-        synchronized(requests) {
-            try {
-                final CompletableDumpFuture<DUMP> replyCompletableFuture;
-                final int contextId = jvpp.send(req);
-
-                if(!(req instanceof JVppDump)) {
-                    throw new IllegalArgumentException("Send without empty reply dump has to be used in case of regular calls");
-                }
-                replyCompletableFuture = new CompletableDumpFuture<>(contextId, emptyReplyDump);
-
-                requests.put(contextId, replyCompletableFuture);
-                requests.put(registry.controlPing(jvpp.getClass()), replyCompletableFuture);
-
-                // TODO in case of timeouts/missing replies, requests from the map are not removed
-                // consider adding cancel method, that would remove requests from the map and cancel
-                // associated replyCompletableFuture
-
-                return replyCompletableFuture;
-            } catch (VppInvocationException ex) {
-                final CompletableFuture<DUMP> replyCompletableFuture = new CompletableFuture<>();
-                replyCompletableFuture.completeExceptionally(ex);
-                return replyCompletableFuture;
-            }
-        }
+      try {
+          // jvpp.send() and registry.controlPing() can go to waiting state if sending queue is full,
+          // putting it into same synchronization block as used by receiving part (synchronized(requests))
+          // can lead to deadlock between these two sides or at least slowing sending process by slow reader
+          final CompletableDumpFuture<DUMP> replyDumpFuture;
+          final int contextId = jvpp.send(req);
+
+          if(!(req instanceof JVppDump)) {
+              throw new IllegalArgumentException("Send without empty reply dump has to be used in case of regular calls");
+          }
+
+          synchronized(requests) {
+              CompletableFuture<? extends JVppReply<?>> replyFuture = requests.get(contextId);
+              if (replyFuture == null) {
+                  // reply not received yet, put new future to map
+                  replyDumpFuture = new CompletableDumpFuture<>(contextId, emptyReplyDump);
+                  requests.put(contextId, replyDumpFuture);
+              } else {
+                  // reply already received, save existing future
+                  replyDumpFuture = (CompletableDumpFuture<DUMP>) replyFuture;
+              }
+          }
+
+          final int pingId = registry.controlPing(jvpp.getClass());
+
+          synchronized(requests) {
+              if (requests.remove(pingId) == null) {
+                  // reply not received yet, put future into map under pingId
+                  requests.put(pingId, replyDumpFuture);
+              } else {
+                  // reply already received, complete future
+                  // ping reply couldn't complete the future because it is not in map under
+                  // ping id
+                  replyDumpFuture.complete(replyDumpFuture.getReplyDump());
+                  requests.remove(contextId);
+              }
+          }
+
+          // TODO in case of timeouts/missing replies, requests from the map are not removed
+          // consider adding cancel method, that would remove requests from the map and cancel
+          // associated replyCompletableFuture
+
+          return replyDumpFuture;
+      } catch (VppInvocationException ex) {
+          final CompletableFuture<DUMP> replyCompletableFuture = new CompletableFuture<>();
+          replyCompletableFuture.completeExceptionally(ex);
+          return replyCompletableFuture;
+      }
     }
 
     public static final class CompletableDumpFuture<T extends JVppReplyDump<?, ?>> extends CompletableFuture<T> {