Changed cache to prevent jar overwriting when update happens.

1 files changed, 245 insertions, 0 deletions

diff --git a/netx/net/sourceforge/jnlp/cache/CacheLRUWrapper.java b/netx/net/sourceforge/jnlp/cache/CacheLRUWrapper.java
new file mode 100644
index 0000000..2a91456
--- /dev/null
+++ b/netx/net/sourceforge/jnlp/cache/CacheLRUWrapper.java
@@ -0,0 +1,245 @@
+/* CacheLRUWrapper -- Handle LRU for cache files.
+   Copyright (C) 2011 Red Hat, Inc.
+
+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 java.io.File;
+import java.io.IOException;
+import java.nio.channels.FileLock;
+import java.nio.channels.OverlappingFileLockException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map.Entry;
+
+import net.sourceforge.jnlp.config.DeploymentConfiguration;
+import net.sourceforge.jnlp.runtime.JNLPRuntime;
+import net.sourceforge.jnlp.util.FileUtils;
+import net.sourceforge.jnlp.util.PropertiesFile;
+
+/**
+ * This class helps maintain the ordering of most recently use items across
+ * multiple jvm instances.
+ * 
+ * @author Andrew Su ([email protected], [email protected])
+ * 
+ */
+enum CacheLRUWrapper {
+    INSTANCE;
+
+    private int lockCount = 0;
+
+    /* lock for the file RecentlyUsed */
+    private FileLock fl = null;
+
+    /* location of cache directory */
+    private final String cacheDir = new File(JNLPRuntime.getConfiguration()
+            .getProperty(DeploymentConfiguration.KEY_USER_CACHE_DIR)).getPath();
+
+    /*
+     * back-end of how LRU is implemented This file is to keep track of the most
+     * recently used items. The items are to be kept with key = (current time
+     * accessed) followed by folder of item. value = path to file.
+     */
+    private PropertiesFile cacheOrder = new PropertiesFile(
+            new File(cacheDir + File.separator + "recently_used"));
+
+    /**
+     * Returns an instance of the policy.
+     * 
+     * @param propertiesFile
+     * @return
+     */
+    public static CacheLRUWrapper getInstance() {
+        return INSTANCE;
+    }
+
+    /**
+     * Update map for keeping track of recently used items.
+     */
+    public synchronized void load() {
+        cacheOrder.load();
+    }
+
+    /**
+     * Write file to disk.
+     */
+    public synchronized void store() {
+        cacheOrder.store();
+    }
+
+    /**
+     * This adds a new entry to file.
+     * 
+     * @param key key we want path to be associated with.
+     * @param path path to cache item.
+     * @return true if we successfully added to map, false otherwise.
+     */
+    public synchronized boolean addEntry(String key, String path) {
+        if (cacheOrder.containsKey(key)) return false;
+        cacheOrder.setProperty(key, path);
+        return true;
+    }
+
+    /**
+     * This removed an entry from our map.
+     * 
+     * @param key key we want to remove.
+     * @return true if we successfully removed key from map, false otherwise.
+     */
+    public synchronized boolean removeEntry(String key) {
+        if (!cacheOrder.containsKey(key)) return false;
+        cacheOrder.remove(key);
+        return true;
+    }
+
+    private String getIdForCacheFolder(String folder) {
+        int len = cacheDir.length();
+        int index = folder.indexOf(File.separatorChar, len + 1);
+        return folder.substring(len + 1, index);
+    }
+
+    /**
+     * This updates the given key to reflect it was recently accessed.
+     * 
+     * @param oldKey Key we wish to update.
+     * @return true if we successfully updated value, false otherwise.
+     */
+    public synchronized boolean updateEntry(String oldKey) {
+        if (!cacheOrder.containsKey(oldKey)) return false;
+        String value = cacheOrder.getProperty(oldKey);
+        String folder = getIdForCacheFolder(value);
+
+        cacheOrder.remove(oldKey);
+        cacheOrder.setProperty(Long.toString(System.currentTimeMillis()) + "," + folder, value);
+        return true;
+    }
+
+    /**
+     * Return a copy of the keys available.
+     * 
+     * @return List of Strings sorted by ascending order.
+     */
+    public synchronized List<Entry<String, String>> getLRUSortedEntries() {
+        ArrayList<Entry<String, String>> entries = new ArrayList(cacheOrder.entrySet());
+        // sort by keys in descending order.
+        Collections.sort(entries, new Comparator<Entry<String, String>>() {
+            @Override
+            public int compare(Entry<String, String> e1, Entry<String, String> e2) {
+                try {
+                    Long t1 = Long.parseLong(e1.getKey().split(",")[0]);
+                    Long t2 = Long.parseLong(e2.getKey().split(",")[0]);
+
+                    int c = t1.compareTo(t2);
+                    return c < 0 ? 1 : (c > 0 ? -1 : 0);
+                } catch (NumberFormatException e) {
+                    // Perhaps an error is too harsh. Maybe just somehow turn
+                    // caching off if this is the case.
+                    throw new InternalError("Corrupt LRU file entries");
+                }
+            }
+        });
+        return entries;
+    }
+
+    /**
+     * Lock the file to have exclusive access.
+     */
+    public synchronized void lock() {
+        try {
+            File f = cacheOrder.getStoreFile();
+            if (!f.exists()) {
+                FileUtils.createParentDir(f);
+                FileUtils.createRestrictedFile(f, true);
+            }
+            fl = FileUtils.getFileLock(f.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.
+     */
+    public synchronized void unlock() {
+        if (fl != null) {
+            lockCount--;
+            try {
+                if (lockCount == 0) {
+                    fl.release();
+                    fl.channel().close();
+                    fl = null;
+                }
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    /**
+     * Return the value of given key.
+     * 
+     * @param key
+     * @return value of given key, null otherwise.
+     */
+    public synchronized String getValue(String key) {
+        return cacheOrder.getProperty(key);
+    }
+
+    /**
+     * Test if we the key provided is in use.
+     * 
+     * @param key key to be tested.
+     * @return true if the key is in use.
+     */
+    public synchronized boolean contains(String key) {
+        return cacheOrder.contains(key);
+    }
+
+    /**
+     * Generate a key given the path to file. May or may not generate the same
+     * key given same path.
+     * 
+     * @param path Path to generate a key with.
+     * @return String representing the a key.
+     */
+    public String generateKey(String path) {
+        return System.currentTimeMillis() + "," + getIdForCacheFolder(path);
+    }
+}