Remove memory leak on resetDriver() when handle TERM signal enabled

fixes #14

webcam-capture/src/main/java/com/github/sarxos/webcam/Webcam.java

@@ -11,6 +11,7 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
+import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
@@ -58,7 +59,7 @@ public void run() {
 		}
 	}
 
-	private static final class WebcamsDiscovery implements Callable<List<Webcam>> {
+	private static final class WebcamsDiscovery implements Callable<List<Webcam>>, ThreadFactory {
 
 		private final WebcamDriver driver;
 
@@ -74,6 +75,13 @@ public List<Webcam> call() throws Exception {
 			}
 			return webcams;
 		}
+
+		@Override
+		public Thread newThread(Runnable r) {
+			Thread t = new Thread(r, "webcam-discovery");
+			t.setDaemon(true);
+			return t;
+		}
 	}
 
 	/**
@@ -180,6 +188,7 @@ public synchronized void close() {
 		}
 
 		Runtime.getRuntime().removeShutdownHook(hook);
+
 		close0();
 	}
 
@@ -362,8 +371,10 @@ public static List<Webcam> getWebcams(long timeout) throws TimeoutException {
 				driver = new WebcamDefaultDriver();
 			}
 
-			ExecutorService executor = Executors.newSingleThreadExecutor();
-			Future<List<Webcam>> future = executor.submit(new WebcamsDiscovery(driver));
+			WebcamsDiscovery discovery = new WebcamsDiscovery(driver);
+			ExecutorService executor = Executors.newSingleThreadExecutor(discovery);
+			Future<List<Webcam>> future = executor.submit(discovery);
+
 			executor.shutdown();
 
 			try {
@@ -537,7 +548,14 @@ public static void resetDriver() {
 
 		driver = null;
 
+		if (deallocOnTermSignal) {
+			WebcamDeallocator.unstore();
+		}
+
 		if (webcams != null && !webcams.isEmpty()) {
+			for (Webcam webcam : webcams) {
+				webcam.dispose();
+			}
 			webcams.clear();
 		}
 
@@ -586,12 +604,21 @@ public WebcamDevice getDevice() {
 	 */
 	protected void dispose() {
 
+		LOG.info("Disposing webcam {}", getName());
+
+		// hook can be null because there is a possibility that webcam has never
+		// been open and therefore hook was not created
+		if (hook != null) {
+			Runtime.getRuntime().removeShutdownHook(hook);
+		}
+
 		open = false;
 		disposed = true;
 
 		WebcamEvent we = new WebcamEvent(this);
 		for (WebcamListener l : listeners) {
 			try {
+				l.webcamClosed(we);
 				l.webcamDisposed(we);
 			} catch (Exception e) {
 				LOG.error(String.format("Notify webcam disposed, exception when calling %s listener", l.getClass()), e);

webcam-capture/src/main/java/com/github/sarxos/webcam/WebcamDeallocator.java

@@ -3,8 +3,6 @@
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.PrintStream;
-import java.util.Observable;
-import java.util.Observer;
 
 
 /**
@@ -13,10 +11,11 @@
  * 
  * @author Bartosz Firyn (SarXos)
  */
-class WebcamDeallocator implements Observer {
+final class WebcamDeallocator {
 
-	private Webcam[] webcams = null;
-	private WebcamSignalHandler handler = new WebcamSignalHandler();
+	private static final WebcamSignalHandler HANDLER = new WebcamSignalHandler();
+
+	private final Webcam[] webcams;
 
 	/**
 	 * This constructor is used internally to create new deallocator for the
@@ -25,43 +24,48 @@ class WebcamDeallocator implements Observer {
 	 * @param devices the devices to be stored in deallocator
 	 */
 	private WebcamDeallocator(Webcam[] devices) {
-		if (devices != null && devices.length > 0) {
-			this.webcams = devices;
-			this.handler.listen("TERM", this);
-		}
+		this.webcams = devices;
 	}
 
 	/**
 	 * Store devices to be deallocated when TERM signal has been received.
 	 * 
-	 * @param devices the devices array to be stored by deallocator
+	 * @param webcams the webcams array to be stored in deallocator
 	 */
-	protected static final void store(Webcam[] devices) {
-		new WebcamDeallocator(devices);
+	protected static final void store(Webcam[] webcams) {
+		if (HANDLER.get() == null) {
+			HANDLER.set(new WebcamDeallocator(webcams));
+		} else {
+			throw new IllegalStateException("Deallocator is already set!");
+		}
 	}
 
-	@Override
-	public void update(Observable observable, Object object) {
-		for (Webcam device : webcams) {
+	protected static final void unstore() {
+		HANDLER.reset();
+	}
+
+	protected void deallocate() {
+		for (Webcam w : webcams) {
 			try {
-				device.dispose();
+				w.dispose();
 			} catch (Throwable t) {
 				caugh(t);
 			}
 		}
 	}
 
-	public void caugh(Throwable e) {
+	private void caugh(Throwable t) {
 		File f = new File(String.format("webcam-capture-hs-%s", System.currentTimeMillis()));
 		PrintStream ps = null;
 		try {
-			e.printStackTrace(ps = new PrintStream(f));
-		} catch (FileNotFoundException e2) {
-			// ignore, stdout is not working, cannot do anything more
+			t.printStackTrace(ps = new PrintStream(f));
+		} catch (FileNotFoundException e) {
+			e.printStackTrace();
 		} finally {
 			if (ps != null) {
 				ps.close();
 			}
 		}
 	}
+
 }

webcam-capture/src/main/java/com/github/sarxos/webcam/WebcamSignalHandler.java

@@ -1,7 +1,7 @@
 package com.github.sarxos.webcam;
 
-import java.util.Observable;
-import java.util.Observer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import sun.misc.Signal;
 import sun.misc.SignalHandler;
@@ -14,29 +14,44 @@
  * @author Bartosz Firyn (SarXos)
  */
 @SuppressWarnings("restriction")
-class WebcamSignalHandler extends Observable implements SignalHandler {
+final class WebcamSignalHandler implements SignalHandler {
+
+	private static final Logger LOG = LoggerFactory.getLogger(WebcamSignalHandler.class);
+
+	private WebcamDeallocator deallocator = null;
 
 	private SignalHandler handler = null;
 
-	public void listen(String signal, Observer observer) throws IllegalArgumentException {
-		addObserver(observer);
-		handler = Signal.handle(new Signal(signal), this);
+	public WebcamSignalHandler() {
+		handler = Signal.handle(new Signal("TERM"), this);
 	}
 
 	@Override
 	public void handle(Signal signal) {
 
+		LOG.warn("Detected signal {} {}, calling deallocator", signal.getName(), signal.getNumber());
+
 		// do nothing on "signal default" or "signal ignore"
 		if (handler == SIG_DFL || handler == SIG_IGN) {
 			return;
 		}
 
-		setChanged();
-
 		try {
-			notifyObservers(signal);
+			deallocator.deallocate();
 		} finally {
 			handler.handle(signal);
 		}
 	}
+
+	public void set(WebcamDeallocator deallocator) {
+		this.deallocator = deallocator;
+	}
+
+	public WebcamDeallocator get() {
+		return this.deallocator;
+	}
+
+	public void reset() {
+		this.deallocator = null;
+	}
 }

webcam-capture/src/main/java/com/github/sarxos/webcam/ds/buildin/WebcamDefaultDriver.java

@@ -2,7 +2,6 @@
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -37,28 +36,20 @@ public class WebcamDefaultDriver implements WebcamDriver {
 	 */
 	private static final GetDevicesTask DEVICES_TASK = new GetDevicesTask(processor);
 
-	/**
-	 * Static devices list.
-	 */
-	private static final List<WebcamDevice> devices = new ArrayList<WebcamDevice>();
-
-	private static final AtomicBoolean initialized = new AtomicBoolean(false);
-
 	@Override
 	public List<WebcamDevice> getDevices() {
 
-		if (initialized.compareAndSet(false, true)) {
+		LOG.debug("Searching devices");
 
-			LOG.debug("Searching devices");
+		List<WebcamDevice> devices = new ArrayList<WebcamDevice>();
 
-			for (Device device : DEVICES_TASK.getDevices()) {
-				devices.add(new WebcamDefaultDevice(device));
-			}
+		for (Device device : DEVICES_TASK.getDevices()) {
+			devices.add(new WebcamDefaultDevice(device));
+		}
 
-			if (LOG.isDebugEnabled()) {
-				for (WebcamDevice device : devices) {
-					LOG.debug("Found device " + device);
-				}
+		if (LOG.isDebugEnabled()) {
+			for (WebcamDevice device : devices) {
+				LOG.debug("Found device {}", device.getName());
 			}
 		}
 

webcam-capture/src/main/java/com/github/sarxos/webcam/ds/buildin/WebcamGrabberProcessor.java

@@ -19,7 +19,7 @@
  * 
  * @author Bartosz Firyn (SarXos)
  */
-public class WebcamGrabberProcessor {
+public final class WebcamGrabberProcessor {
 
 	/**
 	 * Thread factory for processor.