1 files changed, 40 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/shell/FutureCommandResult.java b/src/main/java/com/google/devtools/build/lib/shell/FutureCommandResult.java
new file mode 100644
index 0000000000..3e1f5c9a5f
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/shell/FutureCommandResult.java
@@ -0,0 +1,40 @@
+// Copyright 2014 Google Inc. 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.shell;
+
+/**
+ * Supplier of the command result which additionally allows to check if
+ * the command already terminated. Implementing full fledged Future would
+ * be a much harder undertaking, so a bare minimum that makes this class still
+ * useful for asynchronous command execution is implemented.
+ */
+public interface FutureCommandResult {
+  /**
+   * Returns the result of command execution. If the process is not finished
+   * yet (as reported by {@link #isDone()}, the call will block until that
+   * process terminates.
+   *
+   * @return non-null result of command execution
+   * @throws AbnormalTerminationException if command execution failed
+   */
+  CommandResult get() throws AbnormalTerminationException;
+
+  /**
+   * Returns true if the process terminated, the command result is available
+   * and the call to {@link #get()} will not block.
+   *
+   * @return true if the process terminated
+   */
+  boolean isDone();
+}