The MSSQL row decoder bypasses the decoder flow since handling a row might produce no row. We would like to have the same flow to be used.

The row decoder handleRow method now checks if the returned row is not null before passing it to the collector. In addition we need to use a specific mode to let the mssql decoder which decoding it should use dynamically.

Author: vietj

vertx-mssql-client/src/main/java/io/vertx/mssqlclient/impl/codec/QueryCommandBaseCodec.java

@@ -38,12 +38,14 @@ protected void handleRowDesc(MSSQLRowDesc mssqlRowDesc) {
 
   @Override
   protected void handleRow(ByteBuf payload) {
-    rowResultDecoder.handleRow(payload);
+    rowResultDecoder.nbc = false;
+    rowResultDecoder.handleRow(-1, payload);
   }
 
   @Override
   protected void handleNbcRow(ByteBuf payload) {
-    rowResultDecoder.handleNbcRow(payload);
+    rowResultDecoder.nbc = true;
+    rowResultDecoder.handleRow(-1, payload);
   }
 
   @Override

vertx-mssql-client/src/main/java/io/vertx/mssqlclient/impl/codec/RowResultDecoder.java

@@ -24,8 +24,7 @@ public class RowResultDecoder<C, R> extends RowDecoder<C, R> {
   private static final int FETCH_MISSING = 0x0002;
 
   private final MSSQLRowDesc desc;
-
-  private Row decoded;
+  public boolean nbc;
 
   public RowResultDecoder(Collector<Row, C, R> collector, MSSQLRowDesc desc) {
     super(collector);
@@ -38,23 +37,13 @@ public MSSQLRowDesc desc() {
 
   @Override
   public Row decodeRow(int len, ByteBuf in) {
-    Row row = Objects.requireNonNull(decoded);
-    decoded = null;
-    return row;
-  }
-
-  public void handleRow(ByteBuf in) {
-    decoded = decodeMssqlRow(in);
-    if (decoded != null) {
-      super.handleRow(-1, in);
-    }
-  }
-
-  public void handleNbcRow(ByteBuf in) {
-    decoded = decodeMssqlNbcRow(in);
-    if (decoded != null) {
-      super.handleRow(-1, in);
+    Row decoded;
+    if (nbc) {
+      decoded = decodeMssqlNbcRow(in);
+    } else {
+      decoded = decodeMssqlRow(in);
     }
+    return decoded;
   }
 
   private Row decodeMssqlRow(ByteBuf in) {

vertx-sql-client/src/main/java/io/vertx/sqlclient/impl/RowDecoder.java

@@ -46,25 +46,24 @@ public int size() {
   protected abstract Row decodeRow(int len, ByteBuf in);
 
   public void handleRow(int len, ByteBuf in) {
-    if (failure != null) {
-      return;
-    }
     Row row = decodeRow(len, in);
-    if (accumulator == null) {
+    if (row != null && failure == null) {
+      if (accumulator == null) {
+        try {
+          accumulator = collector.accumulator();
+        } catch (Exception e) {
+          failure = e;
+          return;
+        }
+      }
       try {
-        accumulator = collector.accumulator();
+        accumulator.accept(container, row);
       } catch (Exception e) {
         failure = e;
         return;
       }
+      size++;
     }
-    try {
-      accumulator.accept(container, row);
-    } catch (Exception e) {
-      failure = e;
-      return;
-    }
-    size++;
   }
 
   public R result() {