+/*
+ * Copyright 2015 Facebook, Inc.
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <folly/Executor.h>
+
+namespace folly {
+
+/*
+ * A DrivableExecutor can be driven via its drive() method
+ * Examples include EventBase (via loopOnce()) and ManualExecutor
+ * (via makeProgress()).
+ *
+ * This interface is most handy in conjunction with
+ * Future<T>::getVia(DrivableExecutor*) and
+ * Future<T>::waitVia(DrivableExecutor*)
+ *
+ * These call drive() * repeatedly until the Future is fulfilled.
+ * getVia() returns the value (or throws the exception) and waitVia() returns
+ * the same Future for chainability.
+ *
+ * These will be most helpful in tests, for instance if you need to pump a mock
+ * EventBase until Futures complete.
+ */
+class DrivableExecutor : public virtual Executor {
+ public:
+ virtual ~DrivableExecutor() = default;
+
+ // Make progress on this Executor's work.
+ virtual void drive() = 0;
+};
+
+} // folly