From eb360475aa309618fddc71d650859187463e5853 Mon Sep 17 00:00:00 2001
From: akwizgran <michael@briarproject.org>
Date: Fri, 7 Sep 2012 16:58:03 +0100
Subject: [PATCH] KeyRotatorImpl looks a *lot* like DatabaseCleanerImpl.
---
.../net/sf/briar/db/DatabaseCleaner.java | 6 +--
.../net/sf/briar/db/DatabaseCleanerImpl.java | 6 +--
.../sf/briar/db/DatabaseComponentImpl.java | 3 +-
.../net/sf/briar/db/DatabaseConstants.java | 2 +-
components/net/sf/briar/db/KeyRotator.java | 24 +++++++++
.../net/sf/briar/db/KeyRotatorImpl.java | 41 ++++++++++++++
test/net/sf/briar/db/KeyRotatorImplTest.java | 53 +++++++++++++++++++
7 files changed, 125 insertions(+), 10 deletions(-)
create mode 100644 components/net/sf/briar/db/KeyRotator.java
create mode 100644 components/net/sf/briar/db/KeyRotatorImpl.java
create mode 100644 test/net/sf/briar/db/KeyRotatorImplTest.java
diff --git a/components/net/sf/briar/db/DatabaseCleaner.java b/components/net/sf/briar/db/DatabaseCleaner.java
index 32ecfe316d..639c92d4e3 100644
--- a/components/net/sf/briar/db/DatabaseCleaner.java
+++ b/components/net/sf/briar/db/DatabaseCleaner.java
@@ -19,9 +19,9 @@ interface DatabaseCleaner {
/**
* Checks how much free storage space is available to the database, and
* if necessary expires old messages until the free space is at least
- * DatabaseConstants.MIN_FREE_SPACE. While the free space is less than
- * DatabaseConstants.CRITICAL_FREE_SPACE, operations that attempt to
- * store messages in the database will block.
+ * DatabaseConstants.MIN_FREE_SPACE. If the free space is less than
+ * DatabaseConstants.CRITICAL_FREE_SPACE and there are no more messages
+ * to expire, an Error will be thrown.
*/
void checkFreeSpaceAndClean() throws DbException;
diff --git a/components/net/sf/briar/db/DatabaseCleanerImpl.java b/components/net/sf/briar/db/DatabaseCleanerImpl.java
index 71574267ed..71322acf82 100644
--- a/components/net/sf/briar/db/DatabaseCleanerImpl.java
+++ b/components/net/sf/briar/db/DatabaseCleanerImpl.java
@@ -33,12 +33,10 @@ class DatabaseCleanerImpl extends TimerTask implements DatabaseCleaner {
callback.checkFreeSpaceAndClean();
}
} catch(DbException e) {
- if(LOG.isLoggable(Level.WARNING))
- LOG.warning(e.toString());
+ if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.toString());
throw new Error(e); // Kill the application
} catch(RuntimeException e) {
- if(LOG.isLoggable(Level.WARNING))
- LOG.warning(e.toString());
+ if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.toString());
throw new Error(e); // Kill the application
}
}
diff --git a/components/net/sf/briar/db/DatabaseComponentImpl.java b/components/net/sf/briar/db/DatabaseComponentImpl.java
index 408d415095..ebe17a3097 100644
--- a/components/net/sf/briar/db/DatabaseComponentImpl.java
+++ b/components/net/sf/briar/db/DatabaseComponentImpl.java
@@ -1548,8 +1548,7 @@ DatabaseCleaner.Callback {
if(freeSpace < CRITICAL_FREE_SPACE && !expired) {
// FIXME: Work out what to do here - the amount of free space
// is critically low and there are no messages left to expire
- System.err.println("Disk space is critical - shutting down");
- System.exit(1);
+ throw new Error("Disk space is critical");
}
Thread.yield();
freeSpace = db.getFreeSpace();
diff --git a/components/net/sf/briar/db/DatabaseConstants.java b/components/net/sf/briar/db/DatabaseConstants.java
index fa013a562d..d177b8c089 100644
--- a/components/net/sf/briar/db/DatabaseConstants.java
+++ b/components/net/sf/briar/db/DatabaseConstants.java
@@ -14,7 +14,7 @@ interface DatabaseConstants {
/**
* The minimum amount of space in bytes that must be kept free on the device
* where the database is stored. If less than this much space is free and
- * there are no more messages to expire, the program will shut down.
+ * there are no more messages to expire, an Error will be thrown.
*/
static final long CRITICAL_FREE_SPACE = 100 * 1024 * 1024; // 100 MiB
diff --git a/components/net/sf/briar/db/KeyRotator.java b/components/net/sf/briar/db/KeyRotator.java
new file mode 100644
index 0000000000..200a1ed24f
--- /dev/null
+++ b/components/net/sf/briar/db/KeyRotator.java
@@ -0,0 +1,24 @@
+package net.sf.briar.db;
+
+import net.sf.briar.api.db.DbException;
+
+interface KeyRotator {
+
+ /**
+ * Starts a new thread to rotate keys periodically. The rotator will pause
+ * for the given number of milliseconds between rotations.
+ */
+ void startRotating(Callback callback, long msBetweenRotations);
+
+ /** Tells the rotator thread to exit. */
+ void stopRotating();
+
+ interface Callback {
+
+ /**
+ * Rotates keys, replacing and destroying any keys that have passed the
+ * ends of their respective retention periods.
+ */
+ void rotateKeys() throws DbException;
+ }
+}
diff --git a/components/net/sf/briar/db/KeyRotatorImpl.java b/components/net/sf/briar/db/KeyRotatorImpl.java
new file mode 100644
index 0000000000..26db0228b3
--- /dev/null
+++ b/components/net/sf/briar/db/KeyRotatorImpl.java
@@ -0,0 +1,41 @@
+package net.sf.briar.db;
+
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import net.sf.briar.api.db.DbException;
+
+class KeyRotatorImpl extends TimerTask implements KeyRotator {
+
+ private static final Logger LOG =
+ Logger.getLogger(KeyRotatorImpl.class.getName());
+
+ private volatile Callback callback = null;
+ private volatile Timer timer = null;
+
+ public void startRotating(Callback callback, long msBetweenRotations) {
+ this.callback = callback;
+ timer = new Timer();
+ timer.scheduleAtFixedRate(this, 0L, msBetweenRotations);
+ }
+
+ public void stopRotating() {
+ if(timer == null) throw new IllegalStateException();
+ timer.cancel();
+ }
+
+ public void run() {
+ if(callback == null) throw new IllegalStateException();
+ try {
+ callback.rotateKeys();
+ } catch(DbException e) {
+ if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.toString());
+ throw new Error(e); // Kill the application
+ } catch(RuntimeException e) {
+ if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.toString());
+ throw new Error(e); // Kill the application
+ }
+ }
+}
diff --git a/test/net/sf/briar/db/KeyRotatorImplTest.java b/test/net/sf/briar/db/KeyRotatorImplTest.java
new file mode 100644
index 0000000000..2470e534e6
--- /dev/null
+++ b/test/net/sf/briar/db/KeyRotatorImplTest.java
@@ -0,0 +1,53 @@
+package net.sf.briar.db;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import net.sf.briar.BriarTestCase;
+import net.sf.briar.api.db.DbException;
+import net.sf.briar.db.KeyRotator.Callback;
+
+import org.junit.Test;
+
+public class KeyRotatorImplTest extends BriarTestCase {
+
+ @Test
+ public void testCleanerRunsPeriodically() throws Exception {
+ final CountDownLatch latch = new CountDownLatch(5);
+ Callback callback = new Callback() {
+
+ public void rotateKeys() throws DbException {
+ latch.countDown();
+ }
+ };
+ KeyRotatorImpl cleaner = new KeyRotatorImpl();
+ // Start the rotator
+ cleaner.startRotating(callback, 10L);
+ // The keys should be rotated five times (allow 5 secs for system load)
+ assertTrue(latch.await(5, TimeUnit.SECONDS));
+ // Stop the rotator
+ cleaner.stopRotating();
+ }
+
+ @Test
+ public void testStoppingCleanerWakesItUp() throws Exception {
+ final CountDownLatch latch = new CountDownLatch(1);
+ Callback callback = new Callback() {
+
+ public void rotateKeys() throws DbException {
+ latch.countDown();
+ }
+ };
+ KeyRotatorImpl cleaner = new KeyRotatorImpl();
+ long start = System.currentTimeMillis();
+ // Start the rotator
+ cleaner.startRotating(callback, 10L * 1000L);
+ // The keys should be rotated once at startup
+ assertTrue(latch.await(5, TimeUnit.SECONDS));
+ // Stop the rotator (it should be waiting between rotations)
+ cleaner.stopRotating();
+ long end = System.currentTimeMillis();
+ // Check that much less than 10 seconds expired
+ assertTrue(end - start < 10L * 1000L);
+ }
+}
--
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