Merge branch 'js/rename'

* js/rename:
  Implemented file path based tie breaking to exact rename detection
  Added more test cases for RenameDetector
  Added very small optimization to exact rename detection
  Fixed Misleading Javadoc
  Added file path similarity to scoring metric in rename detection
  Fixed potential div by zero bug
  Added file size based rename detection optimization
  Create FileHeader from DiffEntry
  log: Implement --follow
  Cache the diff configuration section
  log: Add whitespace ignore options
  Format submodule links during differences
  Redo DiffFormatter API to be easier to use
  log, diff: Add rename detection support
  Implement similarity based rename detection
  Added a preliminary version of rename detection
  Refactored code out of FileHeader to facilitate rename detection

1 files changed, 137 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/SimilarityIndexTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/SimilarityIndexTest.java
new file mode 100644
index 0000000000..d6915eb872
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/SimilarityIndexTest.java
@@ -0,0 +1,137 @@
+/*
+ * 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 junit.framework.TestCase;
+
+import org.eclipse.jgit.lib.Constants;
+
+public class SimilarityIndexTest extends TestCase {
+	public void testIndexing() {
+		SimilarityIndex si = hash("" //
+				+ "A\n" //
+				+ "B\n" //
+				+ "D\n" //
+				+ "B\n" //
+		);
+
+		int key_A = keyFor("A\n");
+		int key_B = keyFor("B\n");
+		int key_D = keyFor("D\n");
+		assertTrue(key_A != key_B && key_A != key_D && key_B != key_D);
+
+		assertEquals(3, si.size());
+		assertEquals(2, si.count(si.findIndex(key_A)));
+		assertEquals(4, si.count(si.findIndex(key_B)));
+		assertEquals(2, si.count(si.findIndex(key_D)));
+	}
+
+	public void testCommonScore_SameFiles() {
+		String text = "" //
+				+ "A\n" //
+				+ "B\n" //
+				+ "D\n" //
+				+ "B\n";
+		SimilarityIndex src = hash(text);
+		SimilarityIndex dst = hash(text);
+		assertEquals(8, src.common(dst));
+		assertEquals(8, dst.common(src));
+
+		assertEquals(100, src.score(dst, 100));
+		assertEquals(100, dst.score(src, 100));
+	}
+
+	public void testCommonScore_EmptyFiles() {
+		SimilarityIndex src = hash("");
+		SimilarityIndex dst = hash("");
+		assertEquals(0, src.common(dst));
+		assertEquals(0, dst.common(src));
+	}
+
+	public void testCommonScore_TotallyDifferentFiles() {
+		SimilarityIndex src = hash("A\n");
+		SimilarityIndex dst = hash("D\n");
+		assertEquals(0, src.common(dst));
+		assertEquals(0, dst.common(src));
+	}
+
+	public void testCommonScore_SimiliarBy75() {
+		SimilarityIndex src = hash("A\nB\nC\nD\n");
+		SimilarityIndex dst = hash("A\nB\nC\nQ\n");
+		assertEquals(6, src.common(dst));
+		assertEquals(6, dst.common(src));
+
+		assertEquals(75, src.score(dst, 100));
+		assertEquals(75, dst.score(src, 100));
+	}
+
+	private static SimilarityIndex hash(String text) {
+		SimilarityIndex src = new SimilarityIndex() {
+			@Override
+			void hash(byte[] raw, int ptr, final int end) {
+				while (ptr < end) {
+					int hash = raw[ptr] & 0xff;
+					int start = ptr;
+					do {
+						int c = raw[ptr++] & 0xff;
+						if (c == '\n')
+							break;
+					} while (ptr < end && ptr - start < 64);
+					add(hash, ptr - start);
+				}
+			}
+		};
+		byte[] raw = Constants.encode(text);
+		src.setFileSize(raw.length);
+		src.hash(raw, 0, raw.length);
+		src.sort();
+		return src;
+	}
+
+	private static int keyFor(String line) {
+		SimilarityIndex si = hash(line);
+		assertEquals("single line scored", 1, si.size());
+		return si.key(0);
+	}
+}