Cache the diff configuration section

This way we don't have to reparse for the rename limit every time
we create a new rename detector for a repository.

Change-Id: I669d031690b85ef4da5e39189be7173fb773fc56
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffConfig.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2010, Google Inc.
+ * 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.diff;
+
+import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.lib.Config.SectionParser;
+
+/** Keeps track of diff related configuration options. */
+public class DiffConfig {
+	/** Key for {@link Config#get(SectionParser)}. */
+	public static final Config.SectionParser<DiffConfig> KEY = new SectionParser<DiffConfig>() {
+		public DiffConfig parse(final Config cfg) {
+			return new DiffConfig(cfg);
+		}
+	};
+
+	private final int renameLimit;
+
+	private DiffConfig(final Config rc) {
+		renameLimit = rc.getInt("diff", "renamelimit", 200);
+	}
+
+	/** @return limit on number of paths to perform inexact rename detection. */
+	public int getRenameLimit() {
+		return renameLimit;
+	}
+}

org.eclipse.jgit/src/org/eclipse/jgit/diff/RenameDetector.java

@@ -54,7 +54,6 @@ import java.util.List;
 import org.eclipse.jgit.JGitText;
 import org.eclipse.jgit.diff.DiffEntry.ChangeType;
 import org.eclipse.jgit.lib.AbbreviatedObjectId;
-import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.NullProgressMonitor;
 import org.eclipse.jgit.lib.ProgressMonitor;
@@ -126,8 +125,8 @@ public class RenameDetector {
 	public RenameDetector(Repository repo) {
 		this.repo = repo;
 
-		Config cfg = repo.getConfig();
-		renameLimit = cfg.getInt("diff", "renamelimit", 200);
+		DiffConfig cfg = repo.getConfig().get(DiffConfig.KEY);
+		renameLimit = cfg.getRenameLimit();
 	}
 
 	/**