Fix Daemon.stop() to actually stop the listener thread

ServerSocket.accept() is not interruptible: a thread busy in accept()
may not react to Thread.interrupt() and may not return from accept()
via an InterruptedException. Close the socket instead to make the
daemon's listener thread terminate.

* Close the listening socket to get the listening thread to exit
  instead of interrupting it.
* Add a stopAndWait() method that stops the listening thread and
  then waits until it has indeed finished.
* Set SO_REUSE_ADDRESS on the listening socket.

Bug: 376369
Change-Id: I9d6014103e6dcb0173daea134feb44dc52c5c69a
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

1 files changed, 96 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/DaemonTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/DaemonTest.java
new file mode 100644
index 0000000000..a5e5441405
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/DaemonTest.java
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2017 Thomas Wolf <thomas.wolf@paranor.ch>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.transport;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.net.InetSocketAddress;
+
+import org.junit.Test;
+
+/**
+ * Daemon tests.
+ */
+public class DaemonTest {
+
+	@Test
+	public void testDaemonStop() throws Exception {
+		Daemon d = new Daemon();
+		d.start();
+		InetSocketAddress address = d.getAddress();
+		assertTrue("Port should be allocated", address.getPort() > 0);
+		assertTrue("Daemon should be running", d.isRunning());
+		Thread.sleep(1000); // Give it time to enter accept()
+		d.stopAndWait();
+		// Try to start a new Daemon again on the same port
+		d = new Daemon(address);
+		d.start();
+		InetSocketAddress newAddress = d.getAddress();
+		assertEquals("New daemon should run on the same port", address,
+				newAddress);
+		assertTrue("Daemon should be running", d.isRunning());
+		Thread.sleep(1000);
+		d.stopAndWait();
+	}
+
+	@Test
+	public void testDaemonRestart() throws Exception {
+		Daemon d = new Daemon();
+		d.start();
+		InetSocketAddress address = d.getAddress();
+		assertTrue("Port should be allocated", address.getPort() > 0);
+		assertTrue("Daemon should be running", d.isRunning());
+		Thread.sleep(1000);
+		d.stopAndWait();
+		// Re-start the same daemon
+		d.start();
+		InetSocketAddress newAddress = d.getAddress();
+		assertEquals("Daemon should again run on the same port", address,
+				newAddress);
+		assertTrue("Daemon should be running", d.isRunning());
+		Thread.sleep(1000);
+		d.stopAndWait();
+	}
+}