Merged IncomingConnectionExecutor and PluginExecutor into IoExecutor.

We don't need two separate executors for long-running IO threads.

briar-core/src/org/briarproject/lifecycle/LifecycleModule.java

@@ -1,18 +1,49 @@
 package org.briarproject.lifecycle;
 
+import static java.util.concurrent.TimeUnit.SECONDS;
+
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.RejectedExecutionHandler;
+import java.util.concurrent.SynchronousQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+
 import javax.inject.Singleton;
 
+import org.briarproject.api.lifecycle.IoExecutor;
 import org.briarproject.api.lifecycle.LifecycleManager;
 import org.briarproject.api.lifecycle.ShutdownManager;
 
 import com.google.inject.AbstractModule;
+import com.google.inject.Provides;
 
 public class LifecycleModule extends AbstractModule {
 
+	private final ExecutorService ioExecutor;
+
+	public LifecycleModule() {
+		// The thread pool is unbounded, so use direct handoff
+		BlockingQueue<Runnable> queue = new SynchronousQueue<Runnable>();
+		// Discard tasks that are submitted during shutdown
+		RejectedExecutionHandler policy =
+				new ThreadPoolExecutor.DiscardPolicy();
+		// Create threads as required and keep them in the pool for 60 seconds
+		ioExecutor = new ThreadPoolExecutor(0, Integer.MAX_VALUE,
+				60, SECONDS, queue, policy);
+	}
+
+	@Override
 	protected void configure() {
 		bind(LifecycleManager.class).to(
 				LifecycleManagerImpl.class).in(Singleton.class);
 		bind(ShutdownManager.class).to(
 				ShutdownManagerImpl.class).in(Singleton.class);
 	}
+
+	@Provides @Singleton @IoExecutor
+	Executor getIoExecutor(LifecycleManager lifecycleManager) {
+		lifecycleManager.registerForShutdown(ioExecutor);
+		return ioExecutor;
+	}
 }