Rollback of commit 822c37816ac669e51bec3853b41849a19ec5e230.

--
PiperOrigin-RevId: 148844518
MOS_MIGRATED_REVID=148844518

1 files changed, 23 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/query2/engine/ThreadSafeCallback.java b/src/main/java/com/google/devtools/build/lib/query2/engine/ThreadSafeCallback.java
new file mode 100644
index 0000000000..950335e38a
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/query2/engine/ThreadSafeCallback.java
@@ -0,0 +1,23 @@
+// Copyright 2014 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.query2.engine;
+
+import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadSafe;
+import com.google.devtools.build.lib.util.ThreadSafeBatchCallback;
+
+/** Marker interface for a {@link Callback} that is {@link ThreadSafe}. */
+@ThreadSafe
+public interface ThreadSafeCallback<T>
+    extends Callback<T>, ThreadSafeBatchCallback<T, QueryException> {
+}