Garbage collector for FileRepositories

Implements a garbage collector for FileRepositories. Main ideas are
copied from the garbage collector for DFS based repos
(DfsGarbageCollector). Added functionalities are
- pruning loose objects
- handling of the index
- packing refs
- handling of reflogs (objects referenced from reflog will not be
pruned/)

These are features of a GC which are not handled in this change and
which should come with subsequent changes:
- unpacking packed objects into loose objects (to support that pruning
packed objects doesn't delete them until they are older than two weeks)
- expiration of reflogs
- support for configuration parameters (e.g. gc.pruneExpire)

Change-Id: I14ea5cb7e0fd1b5c50b994fd77f4e05bfbb9d911
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>

2 files changed, 59 insertions, 0 deletions

diff --git a/org.eclipse.jgit.pgm/META-INF/services/org.eclipse.jgit.pgm.TextBuiltin b/org.eclipse.jgit.pgm/META-INF/services/org.eclipse.jgit.pgm.TextBuiltin
index fa0daaa5fe..d8659c05aa 100644
--- a/org.eclipse.jgit.pgm/META-INF/services/org.eclipse.jgit.pgm.TextBuiltin
+++ b/org.eclipse.jgit.pgm/META-INF/services/org.eclipse.jgit.pgm.TextBuiltin
@@ -30,6 +30,7 @@ org.eclipse.jgit.pgm.UploadPack
 org.eclipse.jgit.pgm.Version
 
 org.eclipse.jgit.pgm.debug.DiffAlgorithms
+org.eclipse.jgit.pgm.debug.Gc
 org.eclipse.jgit.pgm.debug.MakeCacheTree
 org.eclipse.jgit.pgm.debug.ReadDirCache
 org.eclipse.jgit.pgm.debug.RebuildCommitGraph
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/Gc.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/Gc.java
new file mode 100644
index 0000000000..656a97cb16
--- /dev/null
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/Gc.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2012, Christian Halstrick <christian.halstrick@sap.com>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.pgm.debug;
+
+import org.eclipse.jgit.lib.TextProgressMonitor;
+import org.eclipse.jgit.pgm.TextBuiltin;
+import org.eclipse.jgit.storage.file.FileRepository;
+import org.eclipse.jgit.storage.file.GC;
+
+class Gc extends TextBuiltin {
+	@Override
+	protected void run() throws Exception {
+		GC gc = new GC((FileRepository) db);
+		gc.setProgressMonitor(new TextProgressMonitor());
+		gc.gc();
+	}
+}