[tor-commits] [onionoo/master] Properly close BufferedWriter in LockFile.

[karsten at torproject.org]

commit 715f98d356b742a466bb57ef3040bb437fb262a8
Author: Karsten Loesing <karsten.loesing at gmx.net>
Date:   Mon Jun 1 10:40:28 2015 +0200

    Properly close BufferedWriter in LockFile.
    
    Patch by firebrand.  Fixes #15654.
---
 .../java/org/torproject/onionoo/util/LockFile.java |   27 +++++++++++++++++---
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/main/java/org/torproject/onionoo/util/LockFile.java b/src/main/java/org/torproject/onionoo/util/LockFile.java
index 0a1f17d..fc8a792 100644
--- a/src/main/java/org/torproject/onionoo/util/LockFile.java
+++ b/src/main/java/org/torproject/onionoo/util/LockFile.java
@@ -17,6 +17,13 @@ public class LockFile {
 
   private final File lockFile = new File("lock");
 
+  /**
+   * Acquire the lock by writing a lock file with the current time in
+   * milliseconds and return whether this operation was successful.
+   *
+   * @return <code>true</code> if the lock file did not exist and writing
+   * that file now succeeded, <code>false</code> otherwise.
+   */
   public boolean acquireLock() {
     Time time = TimeFactory.getTime();
     try {
@@ -26,10 +33,15 @@ public class LockFile {
       if (this.lockFile.getParentFile() != null) {
         this.lockFile.getParentFile().mkdirs();
       }
-      BufferedWriter bw = new BufferedWriter(new FileWriter(
-          this.lockFile));
-      bw.append("" + time.currentTimeMillis() + "\n");
-      bw.close();
+    } catch (SecurityException e) {
+      log.error("Unable to access lock file location", e);
+      return false;
+    }
+
+    try (BufferedWriter bw = new BufferedWriter(new FileWriter(
+        this.lockFile))) {
+      bw.append(String.valueOf(time.currentTimeMillis()));
+      bw.newLine();
       return true;
     } catch (IOException e) {
       log.error("Caught exception while trying to acquire lock!", e);
@@ -37,6 +49,13 @@ public class LockFile {
     }
   }
 
+  /**
+   * Release the lock by deleting the lock file if it exists and return
+   * whether the file was successfully deleted.
+   *
+   * @return <code>true</code> if the lock file does not exist anymore
+   * when returning, <code>false</code> otherwise.
+   */
   public boolean releaseLock() {
     if (this.lockFile.exists()) {
       this.lockFile.delete();