Option to pass start RevCommit to be blamed on to the BlameGenerator.

This can allow passing a FilteredRevCommit which is the filtered list of
commit graph making it easier for Blame to work on. This can
significantly improve blame performance since blame can skip expensive
RevWalk.

Change-Id: Ie127cb710d004079e9f53a5802130afdb49a7de1

1 files changed, 303 insertions, 26 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/blame/BlameGeneratorTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/blame/BlameGeneratorTest.java
index f47f447375..b175ead8ec 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/blame/BlameGeneratorTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/blame/BlameGeneratorTest.java
@@ -13,50 +13,247 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
+import java.util.Iterator;
+
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.blame.BlameGenerator;
 import org.eclipse.jgit.blame.BlameResult;
 import org.eclipse.jgit.junit.RepositoryTestCase;
 import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.merge.MergeStrategy;
+import org.eclipse.jgit.revwalk.FilteredRevCommit;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.junit.Test;
 
 /** Unit tests of {@link BlameGenerator}. */
 public class BlameGeneratorTest extends RepositoryTestCase {
+
+	public static final String OTHER_FILE = "other_file.txt";
+
+	public static final String INTERESTING_FILE = "interesting_file.txt";
+
 	@Test
-	public void testBoundLineDelete() throws Exception {
-		try (Git git = new Git(db)) {
-			String[] content1 = new String[] { "first", "second" };
-			writeTrashFile("file.txt", join(content1));
-			git.add().addFilepattern("file.txt").call();
+	public void testSingleBlame() throws Exception {
+
+		/**
+		 * <pre>
+		 * (ts) 	OTHER_FILE			INTERESTING_FILE
+		 * 1 		a
+		 * 2	 	a, b
+		 * 3							1, 2				c1 <--
+		 * 4	 	a, b, c										 |
+		 * 5							1, 2, 3				c2---
+		 * </pre>
+		 */
+		try (Git git = new Git(db);
+				RevWalk revWalk = new RevWalk(git.getRepository())) {
+			writeTrashFile(OTHER_FILE, join("a"));
+			git.add().addFilepattern(OTHER_FILE).call();
+			git.commit().setMessage("create file").call();
+
+			writeTrashFile(OTHER_FILE, join("a", "b"));
+			git.add().addFilepattern(OTHER_FILE).call();
+			git.commit().setMessage("amend file").call();
+
+			writeTrashFile(INTERESTING_FILE, join("1", "2"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
 			RevCommit c1 = git.commit().setMessage("create file").call();
 
-			String[] content2 = new String[] { "third", "first", "second" };
-			writeTrashFile("file.txt", join(content2));
-			git.add().addFilepattern("file.txt").call();
-			RevCommit c2 = git.commit().setMessage("create file").call();
+			writeTrashFile(OTHER_FILE, join("a", "b", "c"));
+			git.add().addFilepattern(OTHER_FILE).call();
+			git.commit().setMessage("amend file").call();
 
-			try (BlameGenerator generator = new BlameGenerator(db, "file.txt")) {
-				generator.push(null, db.resolve(Constants.HEAD));
+			writeTrashFile(INTERESTING_FILE, join("1", "2", "3"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
+			RevCommit c2 = git.commit().setMessage("amend file").call();
+
+			RevCommit filteredC1 = new FilteredRevCommit(c1);
+			RevCommit filteredC2 = new FilteredRevCommit(c2, filteredC1);
+
+			revWalk.parseHeaders(filteredC2);
+
+			try (BlameGenerator generator = new BlameGenerator(db,
+					INTERESTING_FILE)) {
+				generator.push(filteredC2);
 				assertEquals(3, generator.getResultContents().size());
 
 				assertTrue(generator.next());
 				assertEquals(c2, generator.getSourceCommit());
 				assertEquals(1, generator.getRegionLength());
+				assertEquals(2, generator.getResultStart());
+				assertEquals(3, generator.getResultEnd());
+				assertEquals(2, generator.getSourceStart());
+				assertEquals(3, generator.getSourceEnd());
+				assertEquals(INTERESTING_FILE, generator.getSourcePath());
+
+				assertTrue(generator.next());
+				assertEquals(c1, generator.getSourceCommit());
+				assertEquals(2, generator.getRegionLength());
 				assertEquals(0, generator.getResultStart());
-				assertEquals(1, generator.getResultEnd());
+				assertEquals(2, generator.getResultEnd());
 				assertEquals(0, generator.getSourceStart());
-				assertEquals(1, generator.getSourceEnd());
-				assertEquals("file.txt", generator.getSourcePath());
+				assertEquals(2, generator.getSourceEnd());
+				assertEquals(INTERESTING_FILE, generator.getSourcePath());
+
+				assertFalse(generator.next());
+			}
+		}
+	}
+
+	@Test
+	public void testMergeSingleBlame() throws Exception {
+		try (Git git = new Git(db);
+				RevWalk revWalk = new RevWalk(git.getRepository())) {
+
+			/**
+			 *
+			 *
+			 * <pre>
+			 *  refs/heads/master
+			 *      A
+			 *     / \       		 refs/heads/side
+			 *    /   ---------------->  side
+			 *   /                        |
+			 *  merge <-------------------
+			 * </pre>
+			 */
+
+			writeTrashFile(INTERESTING_FILE, join("1", "2"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
+			RevCommit c1 = git.commit().setMessage("create file").call();
+
+			createBranch(c1, "refs/heads/side");
+			checkoutBranch("refs/heads/side");
+			writeTrashFile(INTERESTING_FILE, join("1", "2", "3", "4"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
+			RevCommit sideCommit = git.commit()
+					.setMessage("amend file in another branch").call();
+
+			checkoutBranch("refs/heads/master");
+			git.merge().setMessage("merge").include(sideCommit)
+					.setStrategy(MergeStrategy.RESOLVE).call();
+
+			Iterator<RevCommit> it = git.log().call().iterator();
+			RevCommit mergeCommit = it.next();
+
+			RevCommit filteredC1 = new FilteredRevCommit(c1);
+			RevCommit filteredSide = new FilteredRevCommit(sideCommit,
+					filteredC1);
+			RevCommit filteredMerge = new FilteredRevCommit(mergeCommit,
+					filteredSide, filteredC1);
+
+			revWalk.parseHeaders(filteredMerge);
+
+			try (BlameGenerator generator = new BlameGenerator(db,
+					INTERESTING_FILE)) {
+				generator.push(filteredMerge);
+				assertEquals(4, generator.getResultContents().size());
 
 				assertTrue(generator.next());
-				assertEquals(c1, generator.getSourceCommit());
+				assertEquals(mergeCommit, generator.getSourceCommit());
 				assertEquals(2, generator.getRegionLength());
-				assertEquals(1, generator.getResultStart());
+				assertEquals(2, generator.getResultStart());
+				assertEquals(4, generator.getResultEnd());
+				assertEquals(2, generator.getSourceStart());
+				assertEquals(4, generator.getSourceEnd());
+				assertEquals(INTERESTING_FILE, generator.getSourcePath());
+
+				assertTrue(generator.next());
+				assertEquals(filteredC1, generator.getSourceCommit());
+				assertEquals(2, generator.getRegionLength());
+				assertEquals(0, generator.getResultStart());
+				assertEquals(2, generator.getResultEnd());
+				assertEquals(0, generator.getSourceStart());
+				assertEquals(2, generator.getSourceEnd());
+				assertEquals(INTERESTING_FILE, generator.getSourcePath());
+
+				assertFalse(generator.next());
+			}
+		}
+	}
+
+	@Test
+	public void testMergeBlame() throws Exception {
+		try (Git git = new Git(db);
+				RevWalk revWalk = new RevWalk(git.getRepository())) {
+
+			/**
+			 *
+			 *
+			 * <pre>
+			 *  refs/heads/master
+			 *      A
+			 *     / \       		 refs/heads/side
+			 *    B   ---------------->  side
+			 *   /                        |
+			 *  merge <-------------------
+			 * </pre>
+			 */
+			writeTrashFile(INTERESTING_FILE, join("1", "2"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
+			RevCommit c1 = git.commit().setMessage("create file").call();
+
+			createBranch(c1, "refs/heads/side");
+			checkoutBranch("refs/heads/side");
+			writeTrashFile(INTERESTING_FILE, join("1", "2", "3"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
+			RevCommit sideCommit = git.commit().setMessage("amend file").call();
+
+			checkoutBranch("refs/heads/master");
+			writeTrashFile(INTERESTING_FILE, join("1", "2", "4"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
+			RevCommit c2 = git.commit().setMessage("delete and amend file")
+					.call();
+
+			git.merge().setMessage("merge").include(sideCommit)
+					.setStrategy(MergeStrategy.RESOLVE).call();
+			writeTrashFile(INTERESTING_FILE, join("1", "2", "3", "4"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
+			RevCommit mergeCommit = git.commit().setMessage("merge commit")
+					.call();
+
+			RevCommit filteredC1 = new FilteredRevCommit(c1);
+			RevCommit filteredSide = new FilteredRevCommit(sideCommit,
+					filteredC1);
+			RevCommit filteredC2 = new FilteredRevCommit(c2, filteredC1);
+
+			RevCommit filteredMerge = new FilteredRevCommit(mergeCommit,
+					filteredSide, filteredC2);
+
+			revWalk.parseHeaders(filteredMerge);
+
+			try (BlameGenerator generator = new BlameGenerator(db,
+					INTERESTING_FILE)) {
+				generator.push(filteredMerge);
+				assertEquals(4, generator.getResultContents().size());
+
+				assertTrue(generator.next());
+				assertEquals(filteredC2, generator.getSourceCommit());
+				assertEquals(1, generator.getRegionLength());
+				assertEquals(3, generator.getResultStart());
+				assertEquals(4, generator.getResultEnd());
+				assertEquals(2, generator.getSourceStart());
+				assertEquals(3, generator.getSourceEnd());
+				assertEquals(INTERESTING_FILE, generator.getSourcePath());
+
+				assertTrue(generator.next());
+				assertEquals(filteredSide, generator.getSourceCommit());
+				assertEquals(1, generator.getRegionLength());
+				assertEquals(2, generator.getResultStart());
 				assertEquals(3, generator.getResultEnd());
+				assertEquals(2, generator.getSourceStart());
+				assertEquals(3, generator.getSourceEnd());
+				assertEquals(INTERESTING_FILE, generator.getSourcePath());
+
+				assertTrue(generator.next());
+				assertEquals(filteredC1, generator.getSourceCommit());
+				assertEquals(2, generator.getRegionLength());
+				assertEquals(0, generator.getResultStart());
+				assertEquals(2, generator.getResultEnd());
 				assertEquals(0, generator.getSourceStart());
 				assertEquals(2, generator.getSourceEnd());
-				assertEquals("file.txt", generator.getSourcePath());
+				assertEquals(INTERESTING_FILE, generator.getSourcePath());
 
 				assertFalse(generator.next());
 			}
@@ -64,6 +261,83 @@ public class BlameGeneratorTest extends RepositoryTestCase {
 	}
 
 	@Test
+	public void testSingleBlame_compareWithWalk() throws Exception {
+		/**
+		 * <pre>
+		 * (ts) 	OTHER_FILE			INTERESTING_FILE
+		 * 1 		a
+		 * 2	 	a, b
+		 * 3							1, 2				c1 <--
+		 * 4	 	a, b, c										 |
+		 * 6							3, 1, 2				c2---
+		 * </pre>
+		 */
+		try (Git git = new Git(db);
+				RevWalk revWalk = new RevWalk(git.getRepository())) {
+			writeTrashFile(OTHER_FILE, join("a"));
+			git.add().addFilepattern(OTHER_FILE).call();
+			git.commit().setMessage("create file").call();
+
+			writeTrashFile(OTHER_FILE, join("a", "b"));
+			git.add().addFilepattern(OTHER_FILE).call();
+			git.commit().setMessage("amend file").call();
+
+			writeTrashFile(INTERESTING_FILE, join("1", "2"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
+			RevCommit c1 = git.commit().setMessage("create file").call();
+
+			writeTrashFile(OTHER_FILE, join("a", "b", "c"));
+			git.add().addFilepattern(OTHER_FILE).call();
+			git.commit().setMessage("amend file").call();
+
+			writeTrashFile(INTERESTING_FILE, join("3", "1", "2"));
+			git.add().addFilepattern(INTERESTING_FILE).call();
+			RevCommit c2 = git.commit().setMessage("prepend").call();
+
+			RevCommit filteredC1 = new FilteredRevCommit(c1);
+			RevCommit filteredC2 = new FilteredRevCommit(c2, filteredC1);
+
+			revWalk.parseHeaders(filteredC2);
+
+			try (BlameGenerator g1 = new BlameGenerator(db, INTERESTING_FILE);
+					BlameGenerator g2 = new BlameGenerator(db,
+							INTERESTING_FILE)) {
+				g1.push(null, c2);
+				g2.push(null, filteredC2);
+
+				assertEquals(g1.getResultContents().size(),
+						g2.getResultContents().size()); // 3
+
+				assertTrue(g1.next());
+				assertTrue(g2.next());
+
+				assertEquals(g1.getSourceCommit(), g2.getSourceCommit()); // c2
+				assertEquals(INTERESTING_FILE, g1.getSourcePath());
+				assertEquals(g1.getRegionLength(), g2.getRegionLength()); // 1
+				assertEquals(g1.getResultStart(), g2.getResultStart()); // 0
+				assertEquals(g1.getResultEnd(), g2.getResultEnd()); // 1
+				assertEquals(g1.getSourceStart(), g2.getSourceStart()); // 0
+				assertEquals(g1.getSourceEnd(), g2.getSourceEnd()); // 1
+				assertEquals(g1.getSourcePath(), g2.getSourcePath()); // INTERESTING_FILE
+
+				assertTrue(g1.next());
+				assertTrue(g2.next());
+
+				assertEquals(g1.getSourceCommit(), g2.getSourceCommit()); // c1
+				assertEquals(g1.getRegionLength(), g2.getRegionLength()); // 2
+				assertEquals(g1.getResultStart(), g2.getResultStart()); // 1
+				assertEquals(g1.getResultEnd(), g2.getResultEnd()); // 3
+				assertEquals(g1.getSourceStart(), g2.getSourceStart()); // 0
+				assertEquals(g1.getSourceEnd(), g2.getSourceEnd()); // 2
+				assertEquals(g1.getSourcePath(), g2.getSourcePath()); // INTERESTING_FILE
+
+				assertFalse(g1.next());
+				assertFalse(g2.next());
+			}
+		}
+	}
+
+	@Test
 	public void testRenamedBoundLineDelete() throws Exception {
 		try (Git git = new Git(db)) {
 			final String FILENAME_1 = "subdir/file1.txt";
@@ -87,7 +361,8 @@ public class BlameGeneratorTest extends RepositoryTestCase {
 			git.add().addFilepattern(FILENAME_2).call();
 			RevCommit c2 = git.commit().setMessage("change file2").call();
 
-			try (BlameGenerator generator = new BlameGenerator(db, FILENAME_2)) {
+			try (BlameGenerator generator = new BlameGenerator(db,
+					FILENAME_2)) {
 				generator.push(null, db.resolve(Constants.HEAD));
 				assertEquals(3, generator.getResultContents().size());
 
@@ -113,7 +388,8 @@ public class BlameGeneratorTest extends RepositoryTestCase {
 			}
 
 			// and test again with other BlameGenerator API:
-			try (BlameGenerator generator = new BlameGenerator(db, FILENAME_2)) {
+			try (BlameGenerator generator = new BlameGenerator(db,
+					FILENAME_2)) {
 				generator.push(null, db.resolve(Constants.HEAD));
 				BlameResult result = generator.computeBlameResult();
 
@@ -136,21 +412,22 @@ public class BlameGeneratorTest extends RepositoryTestCase {
 		try (Git git = new Git(db)) {
 			String[] content1 = new String[] { "first", "second", "third" };
 
-			writeTrashFile("file.txt", join(content1));
-			git.add().addFilepattern("file.txt").call();
+			writeTrashFile(INTERESTING_FILE, join(content1));
+			git.add().addFilepattern(INTERESTING_FILE).call();
 			git.commit().setMessage("create file").call();
 
 			String[] content2 = new String[] { "" };
 
-			writeTrashFile("file.txt", join(content2));
-			git.add().addFilepattern("file.txt").call();
+			writeTrashFile(INTERESTING_FILE, join(content2));
+			git.add().addFilepattern(INTERESTING_FILE).call();
 			git.commit().setMessage("create file").call();
 
-			writeTrashFile("file.txt", join(content1));
-			git.add().addFilepattern("file.txt").call();
+			writeTrashFile(INTERESTING_FILE, join(content1));
+			git.add().addFilepattern(INTERESTING_FILE).call();
 			RevCommit c3 = git.commit().setMessage("create file").call();
 
-			try (BlameGenerator generator = new BlameGenerator(db, "file.txt")) {
+			try (BlameGenerator generator = new BlameGenerator(db,
+					INTERESTING_FILE)) {
 				generator.push(null, db.resolve(Constants.HEAD));
 				assertEquals(3, generator.getResultContents().size());