1 files changed, 63 insertions, 0 deletions
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/RepositoryCache.java b/org.eclipse.egit.core/src/org/eclipse/egit/core/RepositoryCache.java
new file mode 100644
index 0000000000..ca7f96c3ed
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+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/RepositoryCache.java
@@ -0,0 +1,63 @@
+/*******************************************************************************
+ * Copyright (C) 2010, Jens Baumgart <jens.baumgart@sap.com>
+ * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
+ * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
+ * Copyright (C) 2008, Google Inc.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.egit.core;
+
+import java.io.File;
+import java.io.IOException;
+import java.lang.ref.Reference;
+import java.lang.ref.WeakReference;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+
+import org.eclipse.jgit.lib.Repository;
+
+/**
+ * Central cache for Repository instances
+ *
+ */
+public class RepositoryCache {
+	private final Map<File, Reference<Repository>> repositoryCache = new HashMap<File, Reference<Repository>>();
+
+	RepositoryCache() {
+		// package private constructor
+	}
+
+	/**
+	 *
+	 * @param gitDir
+	 * @return an existing instance of Repository for <code>gitDir</code> or a
+	 *         new one if no Repository instance for <code>gitDir</code> exists
+	 *         in the cache.
+	 * @throws IOException
+	 */
+	public synchronized Repository lookupRepository(final File gitDir)
+			throws IOException {
+		Reference<Repository> r = repositoryCache.get(gitDir);
+		Repository d = r != null ? r.get() : null;
+		if (d == null) {
+			d = new Repository(gitDir);
+			repositoryCache.put(gitDir, new WeakReference<Repository>(d));
+		}
+		prune(repositoryCache);
+		return d;
+	}
+
+	private static <K, V> void prune(Map<K, Reference<V>> map) {
+		for (final Iterator<Map.Entry<K, Reference<V>>> i = map.entrySet()
+				.iterator(); i.hasNext();) {
+			if (i.next().getValue().get() == null)
+				i.remove();
+		}
+	}
+
+}