Reduce no. of loads of the cache index file

6 files changed, 368 insertions, 25 deletions

diff --git a/ChangeLog b/ChangeLog
index 82c0feb..65eb995 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2012-05-11  Thomas Meyer  <[email protected]>
+
+	* tests/netx/unit/net/sourceforge/jnlp/util/PropertiesFileTest.java: Add
+	some unit tests for the PropertiesFile class 
+	* tests/netx/unit/net/sourceforge/jnlp/cache/CacheLRUWrapperTest.java: Add
+	some unit tests for the CacheLRUWrapper class
+	* netx/net/sourceforge/jnlp/util/PropertiesFile.java: Use last
+	modification timestamp of the underlying file to lazy load properties.
+	(load): Only reload file, if the file modification timestamp has changed.
+	(store): Actually fsync() the file to disk.
+	* netx/net/sourceforge/jnlp/services/XPersistenceService.java (create):
+	Fix coding style
+	* netx/net/sourceforge/jnlp/cache/CacheLRUWrapper.java (load): Only check
+	data when the recently_used file was reloaded.
+
 2012-05-02  Jiri Vanek  <[email protected]>
 
 	Introduced new annotations Bug (to connect test/reproducer with documentation)
diff --git a/netx/net/sourceforge/jnlp/cache/CacheLRUWrapper.java b/netx/net/sourceforge/jnlp/cache/CacheLRUWrapper.java
index a1eef67..4a23520 100644
--- a/netx/net/sourceforge/jnlp/cache/CacheLRUWrapper.java
+++ b/netx/net/sourceforge/jnlp/cache/CacheLRUWrapper.java
@@ -108,11 +108,11 @@ enum CacheLRUWrapper {
      * Update map for keeping track of recently used items.
      */
     public synchronized void load() {
-        cacheOrder.load();
+        boolean loaded = cacheOrder.load();
         /* 
          * clean up possibly corrupted entries
          */
-        if (checkData()) {
+        if (loaded && checkData()) {
             if (JNLPRuntime.isDebug()) {
                 new LruCacheException().printStackTrace();
             }
@@ -125,7 +125,7 @@ enum CacheLRUWrapper {
     /**
      * check content of cacheOrder and remove invalid/corrupt entries
      *
-     * @return true, if cache was coruupted and affected entry removed
+     * @return true, if cache was corrupted and affected entry removed
      */
     private boolean checkData () {
         boolean modified = false;
diff --git a/netx/net/sourceforge/jnlp/services/XPersistenceService.java b/netx/net/sourceforge/jnlp/services/XPersistenceService.java
index 3e847c9..f3a638f 100644
--- a/netx/net/sourceforge/jnlp/services/XPersistenceService.java
+++ b/netx/net/sourceforge/jnlp/services/XPersistenceService.java
@@ -127,9 +127,10 @@ class XPersistenceService implements PersistenceService {
         checkLocation(location);
 
         File file = toCacheFile(location);
-        if (!file.exists())
+        if (!file.exists()) {
             throw new FileNotFoundException("Persistence store for "
                     + location.toString() + " is not found.");
+        }
         FileUtils.createParentDir(file, "Persistence store for "
                     + location.toString());
 
diff --git a/netx/net/sourceforge/jnlp/util/PropertiesFile.java b/netx/net/sourceforge/jnlp/util/PropertiesFile.java
index 69dbf53..b9dd176 100644
--- a/netx/net/sourceforge/jnlp/util/PropertiesFile.java
+++ b/netx/net/sourceforge/jnlp/util/PropertiesFile.java
@@ -35,9 +35,9 @@ public class PropertiesFile extends Properties {
 
     /** the header string */
     String header = "netx file";
-
-    /** lazy loaded on getProperty */
-    boolean loaded = false;
+    
+    /** time of last modification, lazy loaded on getProperty */
+    long lastStore;
 
     /**
      * Create a properties object backed by the specified file.
@@ -64,7 +64,7 @@ public class PropertiesFile extends Properties {
      * does not exist.
      */
     public String getProperty(String key) {
-        if (!loaded)
+        if (lastStore == 0)
             load();
 
         return super.getProperty(key);
@@ -75,7 +75,7 @@ public class PropertiesFile extends Properties {
      * if the key does not exist.
      */
     public String getProperty(String key, String defaultValue) {
-        if (!loaded)
+        if (lastStore == 0)
             load();
 
         return super.getProperty(key, defaultValue);
@@ -87,7 +87,7 @@ public class PropertiesFile extends Properties {
      * @return the previous value
      */
     public Object setProperty(String key, String value) {
-        if (!loaded)
+        if (lastStore == 0)
             load();
 
         return super.setProperty(key, value);
@@ -104,39 +104,62 @@ public class PropertiesFile extends Properties {
      * Ensures that the file backing these properties has been
      * loaded; call this method before calling any method defined by
      * a superclass.
+     * 
+     * @return true, if file was (re-)loaded
+     *         false, if file was still current
      */
-    public void load() {
-        loaded = true;
+    public boolean load() {
 
-        InputStream s = null;
-        try {
-            if (!file.exists())
-                return;
+        if (!file.exists()) {
+            return false;
+        }
 
+        long currentStore = file.lastModified();
+        long currentTime = System.currentTimeMillis();
+
+        /* (re)load file, if
+         *  - it wasn't loaded/stored, yet (lastStore == 0)
+         *  - current file modification timestamp has changed since last store (currentStore != lastStore) OR
+         *  - current file modification timestamp has not changed since last store AND current system time equals current file modification timestamp
+         *    This is necessary because some filesystems seems only to provide accuracy of the timestamp on the level of seconds!
+         */
+        if(lastStore == 0 || currentStore != lastStore || (currentStore == lastStore && currentStore / 1000 == currentTime / 1000)) {
+            InputStream s = null;
             try {
-                s = new FileInputStream(file);
-                load(s);
-            } finally {
-                if (s != null) s.close();
+
+                try {
+                    s = new FileInputStream(file);
+                    load(s);
+                } finally {
+                    if (s != null) {
+                        s.close();
+                        lastStore=currentStore;
+                        return true;
+                    }
+                }
+            } catch (IOException ex) {
+                ex.printStackTrace();
             }
-        } catch (IOException ex) {
-            ex.printStackTrace();
         }
+
+        return false;
     }
 
     /**
      * Saves the properties to the file.
      */
     public void store() {
-        if (!loaded)
-            return; // nothing could have changed so save unnecessary load/save
 
-        OutputStream s = null;
+        FileOutputStream s = null;
         try {
             try {
                 file.getParentFile().mkdirs();
                 s = new FileOutputStream(file);
                 store(s, header);
+
+                // fsync()
+                s.getChannel().force(true);
+                lastStore = file.lastModified();
             } finally {
                 if (s != null) s.close();
             }
diff --git a/tests/netx/unit/net/sourceforge/jnlp/cache/CacheLRUWrapperTest.java b/tests/netx/unit/net/sourceforge/jnlp/cache/CacheLRUWrapperTest.java
new file mode 100644
index 0000000..584e4b7
--- /dev/null
+++ b/tests/netx/unit/net/sourceforge/jnlp/cache/CacheLRUWrapperTest.java
@@ -0,0 +1,153 @@
+/* CacheLRUWrapperTest.java
+   Copyright (C) 2012 Thomas Meyer
+
+This file is part of IcedTea.
+
+IcedTea is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License as published by
+the Free Software Foundation, version 2.
+
+IcedTea is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with IcedTea; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version.
+*/
+
+package net.sourceforge.jnlp.cache;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+
+import net.sourceforge.jnlp.config.DeploymentConfiguration;
+import net.sourceforge.jnlp.runtime.JNLPRuntime;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class CacheLRUWrapperTest {
+
+    private final CacheLRUWrapper clw = CacheLRUWrapper.getInstance();
+    private final String cacheDir = new File(JNLPRuntime.getConfiguration()
+            .getProperty(DeploymentConfiguration.KEY_USER_CACHE_DIR)).getPath();
+
+    // does no DeploymentConfiguration exist for this file name? 
+    private final String cacheIndexFileName = "recently_used";
+
+    private final int noEntriesCacheFile = 1000;
+
+    @BeforeClass
+    static public void setupJNLPRuntimeConfig() {
+        JNLPRuntime.getConfiguration().setProperty(DeploymentConfiguration.KEY_USER_CACHE_DIR, System.getProperty("java.io.tmpdir"));
+    }
+    
+    @Test
+    public void testLoadStoreTiming() throws InterruptedException {
+
+        int noLoops = 1000;
+
+        long time[] = new long[noLoops];
+
+        clw.lock();
+        clearCacheIndexFile();
+
+        fillCacheIndexFile(noEntriesCacheFile);
+        clw.store();
+
+        // FIXME: wait a second, because of file modification timestamp only provides accuracy on seconds.
+        Thread.sleep(1000);
+
+        long sum = 0;
+        for(int i=0; i < noLoops - 1; i++) {
+            time[i]= System.nanoTime();
+            clw.load();
+            time[i+1]= System.nanoTime();
+            if(i==0)
+                continue;
+            sum = sum + time[i] - time[i-1];
+        }
+        
+        double avg = sum / time.length;
+        System.out.println("Average = " + avg + "ns");
+
+        // wait more than 100 microseconds for noLoops = 1000 and noEntries=1000 is bad
+        assertTrue("load() must not take longer than 100 µs, but took in avg " + avg/1000 + "µs", avg < 100 * 1000);
+
+        clw.unlock();
+    }
+
+    private void fillCacheIndexFile(int noEntries) {
+
+        // fill cache index file
+        for(int i = 0; i < noEntries; i++) {
+            String path = cacheDir + File.separatorChar + i + File.separatorChar + "test" + i + ".jar";
+            String key = clw.generateKey(path);
+            clw.addEntry(key, path);
+        }
+    }
+
+    @Test
+    public void testModTimestampAfterStore() throws InterruptedException {
+
+        final File cacheIndexFile = new File(cacheDir + File.separator + cacheIndexFileName);
+
+        clw.lock();
+        
+        // 1. clear cache entries + store
+        long lmBefore = cacheIndexFile.lastModified();
+        clearCacheIndexFile();
+        long lmAfter = cacheIndexFile.lastModified();
+        assertTrue("modification timestamp hasn't changed! Before = " + lmBefore + " After = " + lmAfter, lmBefore < lmAfter);
+
+        // FIXME: wait a second, because of file modification timestamp only provides accuracy on seconds.
+        Thread.sleep(1000);
+
+        // 2. load cache file
+        lmBefore = cacheIndexFile.lastModified();
+        clw.load();
+        lmAfter = cacheIndexFile.lastModified();
+        assertTrue("modification timestamp has changed!", lmBefore == lmAfter);
+
+        // 3. add some cache entries and store
+        lmBefore = cacheIndexFile.lastModified();
+        fillCacheIndexFile(noEntriesCacheFile);
+        clw.store();
+        lmAfter = cacheIndexFile.lastModified();
+        assertTrue("modification timestamp hasn't changed! Before = " + lmBefore + " After = " + lmAfter, lmBefore < lmAfter);
+
+        clw.unlock();
+    }
+    
+    private void clearCacheIndexFile() {
+
+        clw.lock();
+
+        // clear cache + store file
+        clw.clearLRUSortedEntries();
+        clw.store();
+
+        clw.unlock();
+    }
+}
diff --git a/tests/netx/unit/net/sourceforge/jnlp/util/PropertiesFileTest.java b/tests/netx/unit/net/sourceforge/jnlp/util/PropertiesFileTest.java
new file mode 100644
index 0000000..1cd5d88
--- /dev/null
+++ b/tests/netx/unit/net/sourceforge/jnlp/util/PropertiesFileTest.java
@@ -0,0 +1,151 @@
+/*  PropertiesFileTest.java
+   Copyright (C) 2012 Thomas Meyer
+
+This file is part of IcedTea.
+
+IcedTea is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License as published by
+the Free Software Foundation, version 2.
+
+IcedTea is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with IcedTea; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version.
+*/
+
+package net.sourceforge.jnlp.util;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.channels.FileLock;
+import java.nio.channels.OverlappingFileLockException;
+
+import net.sourceforge.jnlp.config.DeploymentConfiguration;
+import net.sourceforge.jnlp.runtime.JNLPRuntime;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class PropertiesFileTest {
+
+    private int lockCount = 0;
+
+    /* lock for the file RecentlyUsed */
+    private FileLock fl = null;
+
+    private final String cacheDir = new File(JNLPRuntime.getConfiguration()
+            .getProperty(DeploymentConfiguration.KEY_USER_CACHE_DIR)).getPath();
+
+    // does no DeploymentConfiguration exist for this file name? 
+    private final String cacheIndexFileName = "recently_used";
+
+    private final PropertiesFile cacheIndexFile = new PropertiesFile(new File(cacheDir + File.separatorChar + cacheIndexFileName));
+    private final int noEntriesCacheFile = 1000;
+
+    @BeforeClass
+    static public void setupJNLPRuntimeConfig() {
+        JNLPRuntime.getConfiguration().setProperty(DeploymentConfiguration.KEY_USER_CACHE_DIR, System.getProperty("java.io.tmpdir"));
+    }
+
+    private void fillCacheIndexFile(int noEntries) {
+
+        // fill cache index file
+        for(int i = 0; i < noEntries; i++) {
+            String path = cacheDir + File.separatorChar + i + File.separatorChar + "test" + i + ".jar";
+            String key = String.valueOf(System.currentTimeMillis());
+            cacheIndexFile.setProperty(key, path);
+        }
+    }
+
+    @Test
+    public void testReloadAfterStore() {
+
+        lock();
+
+        boolean reloaded = false;
+
+        // 1. clear cache entries + store
+        clearCacheIndexFile();
+
+        // 2. load cache file
+        reloaded = cacheIndexFile.load();
+        assertTrue("File was not reloaded!", reloaded);
+
+        // 3. add some cache entries and store
+        fillCacheIndexFile(noEntriesCacheFile);
+        cacheIndexFile.store();
+        reloaded = cacheIndexFile.load();
+        assertTrue("File was not reloaded!", reloaded);
+
+        unlock();
+    }
+    
+    private void clearCacheIndexFile() {
+
+        lock();
+
+        // clear cache + store file
+        cacheIndexFile.clear();
+        cacheIndexFile.store();
+
+        unlock();
+    }
+
+    
+    // add locking, because maybe some JNLP runtime user is running. copy/paste from CacheLRUWrapper
+
+    /**
+     * Lock the file to have exclusive access.
+     */
+    private void lock() {
+        try {
+            fl = FileUtils.getFileLock(cacheIndexFile.getStoreFile().getPath(), false, true);
+        } catch (OverlappingFileLockException e) { // if overlap we just increase the count.
+        } catch (Exception e) { // We didn't get a lock..
+            e.printStackTrace();
+        }
+        if (fl != null) lockCount++;
+    }
+    
+    /**
+     * Unlock the file.
+     */
+    private void unlock() {
+        if (fl != null) {
+            lockCount--;
+            try {
+                if (lockCount == 0) {
+                    fl.release();
+                    fl.channel().close();
+                    fl = null;
+                }
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}