Server-generated column statistics (#4680)

Reintroduces the column statistics feature from DHE. This code is
copied, with a few changes to how it behaves and how it functions:

 * Results are sent to the client in a static table rather than a
 simple object payload.
 * Client can control the max number of unique values to display,
 up to a point (previously the max was technically 19, new default
 is 20).
 * Non-Comparable objects now have their "popularity" counts as well
 as Comparable, until a max limit is reached. Only the most common 20
 entries will be sent to the client.
 * Deephaven "null" values are used to represent that a standard
 deviation or average cannot be computed.

Note that until #188 is solved, the JS API and web UI will not display
the unique value list.

Fixes #697

authorization/src/main/java/io/deephaven/auth/codegen/impl/ObjectServiceAuthWiring.java

@@ -92,11 +92,9 @@ public void onCallStartedMessageStream(AuthContext authContext) {}
 
         public void onMessageReceivedMessageStream(AuthContext authContext, StreamRequest request) {}
 
-        public void onMessageReceivedOpenMessageStream(AuthContext authContext,
-                StreamRequest request) {}
+        public void onMessageReceivedOpenMessageStream(AuthContext authContext, StreamRequest request) {}
 
-        public void onMessageReceivedNextMessageStream(AuthContext authContext,
-                StreamRequest request) {}
+        public void onMessageReceivedNextMessageStream(AuthContext authContext, StreamRequest request) {}
     }
 
     class DenyAll implements ObjectServiceAuthWiring {
@@ -112,13 +110,11 @@ public void onMessageReceivedMessageStream(AuthContext authContext, StreamReques
             ServiceAuthWiring.operationNotAllowed();
         }
 
-        public void onMessageReceivedOpenMessageStream(AuthContext authContext,
-                StreamRequest request) {
+        public void onMessageReceivedOpenMessageStream(AuthContext authContext, StreamRequest request) {
             ServiceAuthWiring.operationNotAllowed();
         }
 
-        public void onMessageReceivedNextMessageStream(AuthContext authContext,
-                StreamRequest request) {
+        public void onMessageReceivedNextMessageStream(AuthContext authContext, StreamRequest request) {
             ServiceAuthWiring.operationNotAllowed();
         }
     }
@@ -144,15 +140,13 @@ public void onMessageReceivedMessageStream(AuthContext authContext, StreamReques
             }
         }
 
-        public void onMessageReceivedOpenMessageStream(AuthContext authContext,
-                StreamRequest request) {
+        public void onMessageReceivedOpenMessageStream(AuthContext authContext, StreamRequest request) {
             if (delegate != null) {
                 delegate.onMessageReceivedOpenMessageStream(authContext, request);
             }
         }
 
-        public void onMessageReceivedNextMessageStream(AuthContext authContext,
-                StreamRequest request) {
+        public void onMessageReceivedNextMessageStream(AuthContext authContext, StreamRequest request) {
             if (delegate != null) {
                 delegate.onMessageReceivedNextMessageStream(authContext, request);
             }

authorization/src/main/java/io/deephaven/auth/codegen/impl/TableServiceContextualAuthWiring.java

@@ -15,6 +15,7 @@
 import io.deephaven.proto.backplane.grpc.AjRajTablesRequest;
 import io.deephaven.proto.backplane.grpc.ApplyPreviewColumnsRequest;
 import io.deephaven.proto.backplane.grpc.AsOfJoinTablesRequest;
+import io.deephaven.proto.backplane.grpc.ColumnStatisticsRequest;
 import io.deephaven.proto.backplane.grpc.ComboAggregateRequest;
 import io.deephaven.proto.backplane.grpc.CreateInputTableRequest;
 import io.deephaven.proto.backplane.grpc.CrossJoinTablesRequest;
@@ -514,6 +515,17 @@ void checkPermissionSeekRow(AuthContext authContext, SeekRowRequest request,
     void checkPermissionMetaTable(AuthContext authContext, MetaTableRequest request,
             List<Table> sourceTables);
 
+    /**
+     * Authorize a request to ComputeColumnStatistics.
+     *
+     * @param authContext the authentication context of the request
+     * @param request the request to authorize
+     * @param sourceTables the operation's source tables
+     * @throws io.grpc.StatusRuntimeException if the user is not authorized to invoke ComputeColumnStatistics
+     */
+    void checkPermissionComputeColumnStatistics(AuthContext authContext,
+            ColumnStatisticsRequest request, List<Table> sourceTables);
+
     /**
      * A default implementation that funnels all requests to invoke {@code checkPermission}.
      */
@@ -729,6 +741,11 @@ public void checkPermissionMetaTable(AuthContext authContext, MetaTableRequest r
                 List<Table> sourceTables) {
             checkPermission(authContext, sourceTables);
         }
+
+        public void checkPermissionComputeColumnStatistics(AuthContext authContext,
+                ColumnStatisticsRequest request, List<Table> sourceTables) {
+            checkPermission(authContext, sourceTables);
+        }
     }
 
     /**
@@ -1045,5 +1062,12 @@ public void checkPermissionMetaTable(AuthContext authContext, MetaTableRequest r
                 delegate.checkPermissionMetaTable(authContext, request, sourceTables);
             }
         }
+
+        public void checkPermissionComputeColumnStatistics(AuthContext authContext,
+                ColumnStatisticsRequest request, List<Table> sourceTables) {
+            if (delegate != null) {
+                delegate.checkPermissionComputeColumnStatistics(authContext, request, sourceTables);
+            }
+        }
     }
 }