fix nullable struct deserializer

jiuyangzhao · jiuyangzhao · commit 90e6e6fa1942 · 2017-04-13T19:12:40.000-07:00
diff --git a/generator/java.stoneg.py b/generator/java.stoneg.py
@@ -1068,10 +1068,14 @@ def java_serializer(self, data_type):
             return self.fmt('%s.INSTANCE', serializer_class)
         else:
             serializers_class = JavaClass('com.dropbox.core.stone.StoneSerializers')
-            if is_nullable_type(data_type):
+            if is_nullable_type(data_type) and is_struct_type(data_type.data_type):
+                return self.fmt('%s.nullableStruct(%s)',
+                                serializers_class, self.java_serializer(data_type.data_type))
+            elif is_nullable_type(data_type):
                 return self.fmt('%s.nullable(%s)',
                                 serializers_class, self.java_serializer(data_type.data_type))
             elif is_list_type(data_type):
+                # TODO: also support passing collapsed to list serializer
                 return self.fmt('%s.list(%s)',
                                 serializers_class, self.java_serializer(data_type.data_type))
             else:
@@ -3889,7 +3893,7 @@ def generate_union_serialize(self, data_type):
                             w.out('writeTag("%s", g);', field.name)
                             serializer = w.java_serializer(field.data_type)
                             value = 'value.%s' % j.param_name(field)
-                            if j.is_collapsible(field.data_type):
+                            if j.is_collapsible(field.data_type) or is_nullable_type(field.data_type) and j.is_collapsible(field.data_type.data_type):
                                 w.out('%s.serialize(%s, g, true);', serializer, value)
                             else:
                                 w.out('g.writeFieldName("%s");', field.name)
@@ -3940,7 +3944,7 @@ def generate_union_deserialize(self, data_type):
                         w.out('%s fieldValue = null;', j.java_class(field_dt, boxed=True, generics=True))
                         with w.conditional_block(is_nullable_type(field.data_type), 'if (p.getCurrentToken() != JsonToken.END_OBJECT)'):
                             field_serializer = w.java_serializer(field_dt)
-                            if j.is_collapsible(field_dt):
+                            if j.is_collapsible(field_dt) or is_nullable_type(field_dt) and j.is_collapsible(field_dt.data_type):
                                 w.out('fieldValue = %s.deserialize(p, true);', field_serializer)
                             else:
                                 w.out('expectField("%s", p);', field.name)
diff --git a/src/main/java/com/dropbox/core/stone/StoneSerializers.java b/src/main/java/com/dropbox/core/stone/StoneSerializers.java
@@ -62,6 +62,10 @@ public static <T> StoneSerializer<T> nullable(StoneSerializer<T> underlying) {
         return new NullableSerializer<T>(underlying);
     }
 
+    public static <T> StructSerializer<T> nullableStruct(StructSerializer<T> underlying) {
+        return new NullableStructSerializer<T>(underlying);
+    }
+
     public static <T> StoneSerializer<List<T>> list(StoneSerializer<T> underlying) {
         return new ListSerializer<T>(underlying);
     }
@@ -241,6 +245,52 @@ public T deserialize(JsonParser p) throws IOException, JsonParseException {
         }
     }
 
+    private static final class NullableStructSerializer<T> extends StructSerializer<T> {
+        private final StructSerializer<T> underlying;
+
+        public NullableStructSerializer(StructSerializer<T> underlying) {
+            this.underlying = underlying;
+        }
+
+        @Override
+        public void serialize(T value, JsonGenerator g) throws IOException {
+            if (value == null) {
+                g.writeNull();
+            } else {
+                underlying.serialize(value, g);
+            }
+        }
+
+        @Override
+        public void serialize(T value, JsonGenerator g, boolean collapsed) throws IOException {
+            if (value == null) {
+                g.writeNull();
+            } else {
+                underlying.serialize(value, g, collapsed);
+            }
+        }
+
+        @Override
+        public T deserialize(JsonParser p) throws IOException {
+            if (p.getCurrentToken() == JsonToken.VALUE_NULL) {
+                p.nextToken();
+                return null;
+            } else {
+                return underlying.deserialize(p);
+            }
+        }
+
+        @Override
+        public T deserialize(JsonParser p, boolean collapsed) throws IOException {
+            if (p.getCurrentToken() == JsonToken.VALUE_NULL) {
+                p.nextToken();
+                return null;
+            } else {
+                return underlying.deserialize(p, collapsed);
+            }
+        }
+    }
+
     private static final class ListSerializer<T> extends StoneSerializer<List<T>> {
         private final StoneSerializer<T> underlying;
 
