From 6c1351a1fed0c714a6f0b3fa2606c708381ecefc Mon Sep 17 00:00:00 2001
From: Tuukka Lehtonen <tuukka.lehtonen@semantum.fi>
Date: Mon, 16 Oct 2017 22:54:33 +0300
Subject: [PATCH] Improved tracking and disposal robustness of
 DirectorySizeTracker

refs #7551

Change-Id: I2844c5d53a365d2f69aee169772e97e09dbda815
---
 .../file/DirectorySizeTracker.java            | 37 ++++++++++++++++---
 1 file changed, 32 insertions(+), 5 deletions(-)

diff --git a/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/file/DirectorySizeTracker.java b/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/file/DirectorySizeTracker.java
index 6050f4dc9..4746afc89 100644
--- a/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/file/DirectorySizeTracker.java
+++ b/bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/file/DirectorySizeTracker.java
@@ -18,6 +18,7 @@ import static java.nio.file.StandardWatchEventKinds.OVERFLOW;
 
 import java.io.Closeable;
 import java.io.IOException;
+import java.nio.file.AccessDeniedException;
 import java.nio.file.FileSystems;
 import java.nio.file.FileVisitResult;
 import java.nio.file.FileVisitor;
@@ -61,7 +62,7 @@ public class DirectorySizeTracker implements Runnable, Closeable {
 
 	private static final Kind<?>[] ALL_EVENTS = { ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY };
 
-	private static AtomicInteger threadCounter = new AtomicInteger();
+	private static AtomicInteger threadCounter = new AtomicInteger(1);
 
 	private LongConsumer consumer;
 	private Kind<?>[] events;
@@ -86,7 +87,7 @@ public class DirectorySizeTracker implements Runnable, Closeable {
 
 	public static DirectorySizeTracker startTracker(LongConsumer sizeChangeListener) throws IOException {
 		DirectorySizeTracker watcher = new DirectorySizeTracker(sizeChangeListener, ALL_EVENTS);
-		watcher.thread = new Thread(watcher, DirectorySizeTracker.class.getSimpleName() + threadCounter.get());
+		watcher.thread = new Thread(watcher, DirectorySizeTracker.class.getSimpleName() + "-" + threadCounter.get());
 		watcher.thread.start();
 		return watcher;
 	}
@@ -275,6 +276,18 @@ public class DirectorySizeTracker implements Runnable, Closeable {
 			Path dir = trackedDirs.getRight(key);
 			if (dir == null) {
 				LOGGER.error("WatchKey not registered: " + key);
+				for (WatchEvent<?> event : key.pollEvents()) {
+					WatchEvent.Kind<?> kind = event.kind();
+					// TBD - provide example of how OVERFLOW event is handled
+					if (kind == OVERFLOW)
+						continue;
+					// Context for directory entry event is the file name of entry
+					WatchEvent<Path> evt = cast(event);
+					Path name = evt.context();
+					LOGGER.error(String.format("MISSED EVENT: %s: %s", event.kind().name(), name));
+				}
+				boolean valid = key.reset();
+				LOGGER.error("RESET KEY RETURNED: " + valid);
 				continue;
 			}
 
@@ -317,6 +330,8 @@ public class DirectorySizeTracker implements Runnable, Closeable {
 							if (!entrySizes.containsKey(child)) {
 								untrack(child);
 							}
+						} catch (AccessDeniedException e) {
+							// Ignore. This can happen e.g. with temporary locked Lucene index files.
 						} catch (IOException ioe) {
 							LOGGER.error("Failed to read attribute for path " + child, ioe);
 						}
@@ -354,10 +369,23 @@ public class DirectorySizeTracker implements Runnable, Closeable {
 			while (running)
 				processEvents();
 		} finally {
+			// It seems that for some reason cancelling all watch keys
+			// helps the watcher close itself. Otherwise closing the
+			// watch service seemed to get stuck easily.
+			cancelWatchKeys();
 			FileUtils.uncheckedClose(watcher);
 		}
 	}
 
+	private void cancelWatchKeys() {
+		synchronized (lock) {
+			for (WatchKey key : trackedDirs.getLeftSet()) {
+				key.cancel();
+				key.pollEvents();
+			}
+		}
+	}
+
 	/**
 	 * @return total size of the tracked directories in bytes
 	 */
@@ -366,9 +394,8 @@ public class DirectorySizeTracker implements Runnable, Closeable {
 	}
 
 //	public static void main(String[] args) {
-//		try {
-//			DirectorySizeTracker tracker = DirectorySizeTracker.startTracker(null);
-//			tracker.track(Paths.get("d:/track-test"));
+//		try (DirectorySizeTracker tracker = DirectorySizeTracker.startTracker(null)) {
+//			tracker.track(Paths.get("d:/temp dir"));
 //			LOGGER.info("AFTER TRACK: Total size from " + tracker.entrySizes.size() + " files and " + tracker.trackedDirs.size() + " directories is " + tracker.getTotalSize());
 //			Thread.sleep(2000);
 //			//tracker.untrack(Paths.get("d:/track-test"));
-- 
2.43.2