Add support for logAllRefUpdates configuration parameter

Honor the configuration parameter core.logAllRefUpdates when writing
reflogs.  Instead of writing reflog entries always only write
reflogs if this parameter is set to true or if the corresponding
file in the <git-dir>/logs directory already exists. In other words:
if you are updating a ref and this parameter is set to false and
there is no file corresponding to your ref in the <git-dir>/logs
folder then no reflog will be written.

This is a fix for the issue http://code.google.com/p/egit/issues/detail?id=4

Change-Id: I908e4c77e3630dc3223b2d2a47cb4534dbe4ed42
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ReflogConfigTest.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2009, Christian Halstrick <christian.halstrick@sap.com>
+ * Copyright (C) 2009, Christian Halstrick, Matthias Sohn, SAP AG
+ * 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.lib;
+
+import java.io.IOException;
+
+public class ReflogConfigTest extends RepositoryTestCase {
+	public void testlogAllRefUpdates() throws Exception {
+		long commitTime = 1154236443000L;
+		int tz = -4 * 60;
+
+		// check that there are no entries in the reflog and turn off writing
+		// reflogs
+		assertTrue("there should be no entries in reflog", db.getReflogReader(
+				Constants.HEAD).getReverseEntries().size() == 0);
+		db.getConfig().setBoolean("core", null, "logallrefupdates", false);
+
+		// do one commit and check that reflog size is 0: no reflogs should be
+		// written
+		final Tree t = new Tree(db);
+		addFileToTree(t, "i-am-a-file", "and this is the data in me\n");
+		commit(t, "A Commit\n", new PersonIdent(jauthor, commitTime, tz),
+				new PersonIdent(jcommitter, commitTime, tz));
+		commitTime += 100;
+		assertTrue(
+				"Reflog for HEAD still contain no entry",
+				db.getReflogReader(Constants.HEAD).getReverseEntries().size() == 0);
+
+		// set the logAllRefUpdates parameter to true and check it
+		db.getConfig().setBoolean("core", null, "logallrefupdates", true);
+		assertTrue(db.getConfig().getCore().isLogAllRefUpdates());
+
+		// do one commit and check that reflog size is increased to 1
+		addFileToTree(t, "i-am-another-file", "and this is other data in me\n");
+		commit(t, "A Commit\n", new PersonIdent(jauthor, commitTime, tz),
+				new PersonIdent(jcommitter, commitTime, tz));
+		commitTime += 100;
+		assertTrue(
+				"Reflog for HEAD should contain one entry",
+				db.getReflogReader(Constants.HEAD).getReverseEntries().size() == 1);
+
+		// set the logAllRefUpdates parameter to false and check it
+		db.getConfig().setBoolean("core", null, "logallrefupdates", false);
+		assertFalse(db.getConfig().getCore().isLogAllRefUpdates());
+
+		// do one commit and check that reflog size is 2
+		addFileToTree(t, "i-am-anotheranother-file",
+				"and this is other other data in me\n");
+		commit(t, "A Commit\n", new PersonIdent(jauthor, commitTime, tz),
+				new PersonIdent(jcommitter, commitTime, tz));
+		assertTrue(
+				"Reflog for HEAD should contain two entries",
+				db.getReflogReader(Constants.HEAD).getReverseEntries().size() == 2);
+	}
+
+	private void addFileToTree(final Tree t, String filename, String content)
+			throws IOException {
+		FileTreeEntry f = t.addFile(filename);
+		writeTrashFile(f.getName(), content);
+		t.accept(new WriteTree(trash, db), TreeEntry.MODIFIED_ONLY);
+	}
+
+	private void commit(final Tree t, String commitMsg, PersonIdent author,
+			PersonIdent committer) throws IOException {
+		final Commit commit = new Commit(db);
+		commit.setAuthor(author);
+		commit.setCommitter(committer);
+		commit.setMessage(commitMsg);
+		commit.setTree(t);
+		ObjectWriter writer = new ObjectWriter(db);
+		commit.setCommitId(writer.writeCommit(commit));
+
+		int nl = commitMsg.indexOf('\n');
+		final RefUpdate ru = db.updateRef(Constants.HEAD);
+		ru.setNewObjectId(commit.getCommitId());
+		ru.setRefLogMessage("commit : "
+				+ ((nl == -1) ? commitMsg : commitMsg.substring(0, nl)), false);
+		ru.forceUpdate();
+	}
+}

org.eclipse.jgit/src/org/eclipse/jgit/lib/CoreConfig.java

@@ -1,4 +1,5 @@
 /*
+ * Copyright (C) 2009, Christian Halstrick <christian.halstrick@sap.com>
  * Copyright (C) 2009, Google Inc.
  * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
  * Copyright (C) 2006-2008, Shawn O. Pearce <spearce@spearce.org>
@@ -64,9 +65,12 @@ public class CoreConfig {
 
 	private final int packIndexVersion;
 
+	private final boolean logAllRefUpdates;
+
 	private CoreConfig(final Config rc) {
 		compression = rc.getInt("core", "compression", DEFAULT_COMPRESSION);
 		packIndexVersion = rc.getInt("pack", "indexversion", 2);
+		logAllRefUpdates = rc.getBoolean("core", "logallrefupdates", true);
 	}
 
 	/**
@@ -84,4 +88,11 @@ public class CoreConfig {
 	public int getPackIndexVersion() {
 		return packIndexVersion;
 	}
+
+	/**
+	 * @return whether to log all refUpdates
+	 */
+	public boolean isLogAllRefUpdates() {
+		return logAllRefUpdates;
+	}
 }

org.eclipse.jgit/src/org/eclipse/jgit/lib/RefLogWriter.java

@@ -1,4 +1,5 @@
 /*
+ * Copyright (C) 2009, Christian Halstrick <christian.halstrick@sap.com>
  * Copyright (C) 2007, Dave Watson <dwatson@mimvista.com>
  * Copyright (C) 2009, Google Inc.
  * Copyright (C) 2007-2009, Robin Rosenberg <robin.rosenberg@dewire.com>
@@ -119,6 +120,7 @@ public class RefLogWriter {
 		final byte[] rec = Constants.encode(r.toString());
 		final File logdir = new File(db.getDirectory(), Constants.LOGS);
 		final File reflog = new File(logdir, refName);
+		if (reflog.exists() || db.getConfig().getCore().isLogAllRefUpdates()) {
 			final File refdir = reflog.getParentFile();
 
 			if (!refdir.exists() && !refdir.mkdirs())
@@ -131,6 +133,7 @@ public class RefLogWriter {
 				out.close();
 			}
 		}
+	}
 
 	/**
 	 * Writes reflog entry for ref specified by refName

org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java

@@ -193,6 +193,7 @@ public class Repository {
 		cfg.setBoolean("core", null, "filemode", true);
 		if (bare)
 			cfg.setBoolean("core", null, "bare", true);
+		cfg.setBoolean("core", null, "logallrefupdates", !bare);
 		cfg.save();
 	}