Fix loop in auto gc

* GC.tooManyLooseObjects() always responded true since the loop missed
to advance the iterator so it always incremented until the threshold was
exceeded.
* Also fix loop exit criterion which was off by 1.
* Add some tests.

Change-Id: I70976dfaa026efbcf3c46bd45941f37277a18e04
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/AutoGcTest.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2016, Matthias Sohn <matthias.sohn@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.internal.storage.file;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.eclipse.jgit.lib.ConfigConstants;
+import org.eclipse.jgit.storage.file.FileBasedConfig;
+import org.eclipse.jgit.test.resources.SampleDataRepositoryTestCase;
+import org.junit.Test;
+
+public class AutoGcTest extends GcTestCase {
+
+	@Test
+	public void testNotTooManyLooseObjects() {
+		assertFalse("should not find too many loose objects",
+				gc.tooManyLooseObjects());
+	}
+
+	@Test
+	public void testTooManyLooseObjects() throws Exception {
+		FileBasedConfig c = repo.getConfig();
+		c.setInt(ConfigConstants.CONFIG_GC_SECTION, null,
+				ConfigConstants.CONFIG_KEY_AUTO, 255);
+		c.save();
+		commitChain(10, 50);
+		assertTrue("should find too many loose objects",
+				gc.tooManyLooseObjects());
+	}
+
+	@Test
+	public void testNotTooManyPacks() {
+		assertFalse("should not find too many packs", gc.tooManyPacks());
+	}
+
+	@Test
+	public void testTooManyPacks() throws Exception {
+		FileBasedConfig c = repo.getConfig();
+		c.setInt(ConfigConstants.CONFIG_GC_SECTION, null,
+				ConfigConstants.CONFIG_KEY_AUTOPACKLIMIT, 1);
+		c.save();
+		SampleDataRepositoryTestCase.copyCGitTestPacks(repo);
+
+		assertTrue("should find too many packs", gc.tooManyPacks());
+	}
+}

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GcTestCase.java

@@ -105,6 +105,46 @@ public abstract class GcTestCase extends LocalDiskRepositoryTestCase {
 		return tip;
 	}
 
+	/**
+	 * Create a chain of commits of given depth with given number of added files
+	 * per commit.
+	 * <p>
+	 * Each commit contains {@code files} files as its content. The created
+	 * commit chain is referenced from any ref.
+	 * <p>
+	 * A chain will create {@code (2 + files) * depth} objects in Gits object
+	 * database. For each depth level the following objects are created: the
+	 * commit object, the top-level tree object and @code files} blobs for the
+	 * content of the file "a".
+	 *
+	 * @param depth
+	 *            the depth of the commit chain.
+	 * @param width
+	 *            number of files added per commit
+	 * @return the commit that is the tip of the commit chain
+	 * @throws Exception
+	 */
+	protected RevCommit commitChain(int depth, int width) throws Exception {
+		if (depth <= 0) {
+			throw new IllegalArgumentException("Chain depth must be > 0");
+		}
+		if (width <= 0) {
+			throw new IllegalArgumentException("Number of files per commit must be > 0");
+		}
+		CommitBuilder cb = tr.commit();
+		RevCommit tip = null;
+		do {
+			--depth;
+			for (int i=0; i < width; i++) {
+				String id = depth + "-" + i;
+				cb.add("a" + id, id).message(id);
+			}
+			tip = cb.create();
+			cb = cb.child();
+		} while (depth > 0);
+		return tip;
+	}
+
 	protected long lastModified(AnyObjectId objectId) throws IOException {
 		return repo.getFS().lastModified(
 				repo.getObjectDatabase().fileFor(objectId));

org.eclipse.jgit.test/tst/org/eclipse/jgit/test/resources/SampleDataRepositoryTestCase.java

@@ -47,7 +47,9 @@
 package org.eclipse.jgit.test.resources;
 
 import java.io.File;
+import java.io.IOException;
 
+import org.eclipse.jgit.internal.storage.file.FileRepository;
 import org.eclipse.jgit.junit.JGitTestUtil;
 import org.eclipse.jgit.junit.RepositoryTestCase;
 
@@ -57,7 +59,17 @@ public abstract class SampleDataRepositoryTestCase extends RepositoryTestCase {
 	@Override
 	public void setUp() throws Exception {
 		super.setUp();
+		copyCGitTestPacks(db);
+	}
 
+	/**
+	 * Copy C Git generated pack files into given repository for testing
+	 *
+	 * @param repo
+	 *            test repository to receive packfile copies
+	 * @throws IOException
+	 */
+	public static void copyCGitTestPacks(FileRepository repo) throws IOException {
 		final String[] packs = {
 				"pack-34be9032ac282b11fa9babdc2b2a93ca996c9c2f",
 				"pack-df2982f284bbabb6bdb59ee3fcc6eb0983e20371",
@@ -67,13 +79,14 @@ public abstract class SampleDataRepositoryTestCase extends RepositoryTestCase {
 				"pack-e6d07037cbcf13376308a0a995d1fa48f8f76aaa",
 				"pack-3280af9c07ee18a87705ef50b0cc4cd20266cf12"
 		};
-		final File packDir = new File(db.getObjectDatabase().getDirectory(), "pack");
+		final File packDir = new File(repo.getObjectDatabase().getDirectory(),
+				"pack");
 		for (String n : packs) {
 			JGitTestUtil.copyTestResource(n + ".pack", new File(packDir, n + ".pack"));
 			JGitTestUtil.copyTestResource(n + ".idx", new File(packDir, n + ".idx"));
 		}
 
 		JGitTestUtil.copyTestResource("packed-refs",
-				new File(db.getDirectory(), "packed-refs"));
+				new File(repo.getDirectory(), "packed-refs"));
 	}
 }

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java

@@ -1164,7 +1164,7 @@ public class GC {
 	/**
 	 * @return {@code true} if number of packs > gc.autopacklimit (default 50)
 	 */
-	private boolean tooManyPacks() {
+	boolean tooManyPacks() {
 		int autopacklimit = repo.getConfig().getInt(
 				ConfigConstants.CONFIG_GC_SECTION,
 				ConfigConstants.CONFIG_KEY_AUTOPACKLIMIT,
@@ -1183,7 +1183,7 @@ public class GC {
 	 *
 	 * @return {@code true} if number of loose objects > gc.auto (default 6700)
 	 */
-	private boolean tooManyLooseObjects() {
+	boolean tooManyLooseObjects() {
 		int auto = repo.getConfig().getInt(ConfigConstants.CONFIG_GC_SECTION,
 				ConfigConstants.CONFIG_KEY_AUTO, DEFAULT_AUTOLIMIT);
 		if (auto <= 0) {
@@ -1204,9 +1204,9 @@ public class GC {
 								.matches();
 					}
 				})) {
-			Iterator<Path> iter = stream.iterator();
-			while (iter.hasNext()) {
-				if (n++ > threshold) {
+			for (Iterator<Path> iter = stream.iterator(); iter.hasNext();
+					iter.next()) {
+				if (++n > threshold) {
 					return true;
 				}
 			}