Improve directory size update performance

Use NIO Files.walkFileTree() instead of IO File.ListFiles() API.
Speed improvement was ~6.1s -> ~4.4s on my recordings list.

TODO: implement more intelligent refresh.

common/src/main/java/ctbrec/Recording.java

@@ -1,18 +1,31 @@
 package ctbrec;
 
 import java.io.File;
+import java.io.IOException;
 import java.io.Serializable;
+import java.nio.file.FileVisitOption;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
 import java.time.Duration;
 import java.time.Instant;
 import java.time.LocalDateTime;
 import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
+import java.util.EnumSet;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import ctbrec.event.EventBusHolder;
 import ctbrec.event.RecordingStateChangedEvent;
 import ctbrec.recorder.download.Download;
 
 public class Recording implements Serializable {
+    private static final transient Logger LOG = LoggerFactory.getLogger(Recording.class);
+
     private Model model;
     private transient Download download;
     private Instant startDate;
@@ -216,17 +229,26 @@ public class Recording implements Serializable {
     }
 
     private long getDirectorySize(File dir) {
-        long size = 0;
-        if (dir.exists()) {
-            File[] files = dir.listFiles();
-            if (files == null) {
-                return 0;
-            }
-            for (File file : files) {
-                size += file.length();
-            }
+        final long[] size = { 0 };
+        int maxDepth = 1; // Don't expect subdirs, so don't even try
+        try {
+            Files.walkFileTree(dir.toPath(), EnumSet.noneOf(FileVisitOption.class), maxDepth, new SimpleFileVisitor<Path>() {
+                @Override
+                public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
+                    size[0] += attrs.size();
+                    return FileVisitResult.CONTINUE;
+                }
+
+                @Override
+                public FileVisitResult visitFileFailed(Path file, IOException exc) {
+                    // Ignore file access issues
+                    return FileVisitResult.CONTINUE;
+                }
+            });
+        } catch (IOException e) {
+            LOG.error("Couldn't determine size of recording {}", this, e);
         }
-        return size;
+        return size[0];
     }
 
     public void refresh() {

common/src/main/java/ctbrec/recorder/RecordingManager.java

@@ -7,6 +7,7 @@ import static java.nio.file.StandardOpenOption.*;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
+import java.time.Duration;
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
@@ -135,9 +136,13 @@ public class RecordingManager {
     public List<Recording> getAll() {
         recordingsLock.lock();
         try {
+            Instant start = Instant.now();
             for (Recording recording : recordings) {
                 recording.refresh();
             }
+            Instant finish = Instant.now();
+            long timeElapsed = Duration.between(start, finish).toMillis();
+            LOG.trace("Recordings list refreshed in {} ms", timeElapsed);
             return new ArrayList<>(recordings);
         } finally {
             recordingsLock.unlock();