// 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.server.signal;
import com.google.devtools.build.lib.util.Preconditions;
import sun.misc.Signal;
import sun.misc.SignalHandler;
/**
* A facade around sun.misc.Signal providing special-purpose SIGINT handling.
*
* <p>We use this code in preference to using sun.misc directly since the latter is deprecated, and
* depending on it causes the jdk1.6 javac to emit an unsuppressable warning that sun.misc is
* "Sun proprietary API and may be removed in a future release".
*/
public abstract class InterruptSignalHandler implements Runnable {
private static final Signal SIGINT = new Signal("INT");
private SignalHandler oldHandler;
/**
* Constructs an InterruptSignalHandler instance. Until the uninstall()
* method is invoked, the delivery of a SIGINT signal to this process will
* cause the run() method to be invoked in another thread.
*/
protected InterruptSignalHandler() {
this.oldHandler =
Signal.handle(
SIGINT,
new SignalHandler() {
@Override
public void handle(Signal signal) {
run();
}
});
}
/** Disables SIGINT handling. */
public final synchronized void uninstall() {
Preconditions.checkNotNull(oldHandler, "uninstall() already called");
Signal.handle(SIGINT, oldHandler);
oldHandler = null;
}
}