Added filter for merge and non-merges commits.

Added the option to retrieve either merge or non-merge commits in the
LogCommand.

Change-Id: Ie0e1c515a823f2392783f1a47d385c31230e8167
Signed-off-by: Alcemir Santos <alcemir.santos@gmail.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/LogCommandTest.java

@@ -53,7 +53,9 @@
 import org.eclipse.jgit.junit.RepositoryTestCase;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.merge.MergeStrategy;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.filter.RevFilter;
 import org.junit.Test;
 
 public class LogCommandTest extends RepositoryTestCase {
@@ -210,4 +212,81 @@ public void logAllCommitsWithSkipAndMaxCount() throws Exception {
 		assertEquals("commit#2", commit.getShortMessage());
 		assertFalse(log.hasNext());
 	}
+
+	@Test
+	public void logOnlyMergeCommits() throws Exception {
+		setCommitsAndMerge();
+		Git git = Git.wrap(db);
+
+		Iterable<RevCommit> commits = git.log().all().call();
+		Iterator<RevCommit> i = commits.iterator();
+		RevCommit commit = i.next();
+		assertEquals("merge s0 with m1", commit.getFullMessage());
+		commit = i.next();
+		assertEquals("s0", commit.getFullMessage());
+		commit = i.next();
+		assertEquals("m1", commit.getFullMessage());
+		commit = i.next();
+		assertEquals("m0", commit.getFullMessage());
+		assertFalse(i.hasNext());
+
+		commits = git.log().setRevFilter(RevFilter.ONLY_MERGES).call();
+		i = commits.iterator();
+		commit = i.next();
+		assertEquals("merge s0 with m1", commit.getFullMessage());
+		assertFalse(i.hasNext());
+	}
+
+	@Test
+	public void logNoMergeCommits() throws Exception {
+		setCommitsAndMerge();
+		Git git = Git.wrap(db);
+
+		Iterable<RevCommit> commits = git.log().all().call();
+		Iterator<RevCommit> i = commits.iterator();
+		RevCommit commit = i.next();
+		assertEquals("merge s0 with m1", commit.getFullMessage());
+		commit = i.next();
+		assertEquals("s0", commit.getFullMessage());
+		commit = i.next();
+		assertEquals("m1", commit.getFullMessage());
+		commit = i.next();
+		assertEquals("m0", commit.getFullMessage());
+		assertFalse(i.hasNext());
+
+		commits = git.log().setRevFilter(RevFilter.NO_MERGES).call();
+		i = commits.iterator();
+		commit = i.next();
+		assertEquals("m1", commit.getFullMessage());
+		commit = i.next();
+		assertEquals("s0", commit.getFullMessage());
+		commit = i.next();
+		assertEquals("m0", commit.getFullMessage());
+		assertFalse(i.hasNext());
+	}
+
+	private void setCommitsAndMerge() throws Exception {
+		Git git = Git.wrap(db);
+		writeTrashFile("file1", "1\n2\n3\n4\n");
+		git.add().addFilepattern("file1").call();
+		RevCommit masterCommit0 = git.commit().setMessage("m0").call();
+
+		createBranch(masterCommit0, "refs/heads/side");
+		checkoutBranch("refs/heads/side");
+
+		writeTrashFile("file2", "1\n2\n3\n4\n5\n6\n7\n8\n");
+		git.add().addFilepattern("file2").call();
+		RevCommit c = git.commit().setMessage("s0").call();
+
+		checkoutBranch("refs/heads/master");
+
+		writeTrashFile("file3", "1\n2\n");
+		git.add().addFilepattern("file3").call();
+		git.commit().setMessage("m1").call();
+
+		git.merge().include(c.getId())
+				.setStrategy(MergeStrategy.RESOLVE)
+				.setMessage("merge s0 with m1").call();
+	}
+
 }

org.eclipse.jgit/src/org/eclipse/jgit/api/LogCommand.java

@@ -65,6 +65,7 @@
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.revwalk.filter.AndRevFilter;
 import org.eclipse.jgit.revwalk.filter.MaxCountRevFilter;
+import org.eclipse.jgit.revwalk.filter.RevFilter;
 import org.eclipse.jgit.revwalk.filter.SkipRevFilter;
 import org.eclipse.jgit.treewalk.filter.AndTreeFilter;
 import org.eclipse.jgit.treewalk.filter.PathFilter;
@@ -104,6 +105,8 @@ public class LogCommand extends GitCommand<Iterable<RevCommit>> {
 
 	private boolean startSpecified = false;
 
+	private RevFilter revFilter;
+
 	private final List<PathFilter> pathFilters = new ArrayList<PathFilter>();
 
 	private int maxCount = -1;
@@ -156,6 +159,11 @@ else if (maxCount > -1)
 						e);
 			}
 		}
+
+		if (this.revFilter != null) {
+			walk.setRevFilter(this.revFilter);
+		}
+
 		setCallable(false);
 		return walk;
 	}
@@ -342,4 +350,21 @@ private LogCommand add(boolean include, AnyObjectId start)
 					, start), e);
 		}
 	}
+
+
+	/**
+	 * Sets a filter for the <code>LogCommand</code>.
+	 *
+	 *
+	 * @param aFilter
+	 *            the filter that this instance of <code>LogCommand</code>
+	 *            should use
+	 * @return {@code this}
+	 * @since 4.4
+	 */
+	public LogCommand setRevFilter(RevFilter aFilter) {
+		checkCallable();
+		this.revFilter = aFilter;
+		return this;
+	}
 }

org.eclipse.jgit/src/org/eclipse/jgit/revwalk/filter/RevFilter.java

@@ -82,6 +82,7 @@
  * <b>Merge filters:</b>
  * <ul>
  * <li>Skip all merges: {@link #NO_MERGES}.</li>
+ * <li>Skip all non-merges: {@link #ONLY_MERGES}</li>
  * </ul>
  *
  * <p>
@@ -143,6 +144,37 @@ public String toString() {
 		}
 	}
 
+	/**
+	 * Filter including only merge commits, excluding all commits with less than
+	 * two parents (thread safe).
+	 *
+	 * @since 4.4
+	 */
+	public static final RevFilter ONLY_MERGES = new OnlyMergesFilter();
+
+	private static final class OnlyMergesFilter extends RevFilter {
+
+		@Override
+		public boolean include(RevWalk walker, RevCommit c) {
+			return c.getParentCount() >= 2;
+		}
+
+		@Override
+		public RevFilter clone() {
+			return this;
+		}
+
+		@Override
+		public boolean requiresCommitBody() {
+			return false;
+		}
+
+		@Override
+		public String toString() {
+			return "ONLY_MERGES"; //$NON-NLS-1$
+		}
+	}
+
 	/** Excludes commits with more than one parent (thread safe). */
 	public static final RevFilter NO_MERGES = new NoMergesFilter();