com.google.devtools.build.lib.shell.Subprocess Maven / Gradle / Ivy
// Copyright 2016 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.shell;
import java.io.Closeable;
import java.io.InputStream;
import java.io.OutputStream;
/**
* A process started by Bazel.
*/
public interface Subprocess extends Closeable {
/**
* Kill the process.
*/
boolean destroy();
/**
* Returns the exit value of the process.
*
* Throws {@code IllegalThreadStateException} if the process has not terminated yet.
*/
int exitValue();
/**
* Returns the if the process has finished.
*
*
This may cause the process to be destroyed as a side effect, for example due to a timeout.
*/
boolean finished();
/** Returns true if the process is still alive. Does not block or cause any side effects. */
boolean isAlive();
/**
* Returns if the process timed out.
*/
boolean timedout();
/**
* Waits for the process to finish.
*/
void waitFor() throws InterruptedException;
/**
* Returns a stream into which data can be written that the process will get on its stdin.
*/
OutputStream getOutputStream();
/**
* Returns a stream from which the stdout of the process can be read.
*/
InputStream getInputStream();
/**
* Returns a stream from which the stderr of the process can be read.
*/
InputStream getErrorStream();
/*
* Terminates the process as thoroughly as the underlying implementation allows and releases
* native data structures associated with the process.
*/
@Override
void close();
/** Waits for the process to finish in a non-interruptible manner. */
default void waitForUninterruptibly() {
boolean wasInterrupted = false;
try {
while (true) {
try {
waitFor();
return;
} catch (InterruptedException ie) {
wasInterrupted = true;
}
}
} finally {
// Read this for detailed explanation: http://www.ibm.com/developerworks/library/j-jtp05236/
if (wasInterrupted) {
Thread.currentThread().interrupt(); // preserve interrupted status
}
}
}
/**
* Kills the subprocess and awaits for its termination so that we know it has released any
* resources it may have held.
*/
default void destroyAndWait() {
destroy();
waitForUninterruptibly();
}
}