Merge changes I57b1d7c1,I590ac460

* changes:
  Use .addObject and .or instead of .add in AddToBitmapFilter
  Replace anonymous BitmapRevFilter subclasses with explicit classes

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/PackWriterBitmapWalker.java

@@ -110,7 +110,7 @@ final class PackWriterBitmapWalker {
 		}
 
 		if (marked) {
-			BitmapRevFilter filter = newRevFilter(seen, bitmapResult);
+			RevFilter filter = newRevFilter(seen, bitmapResult);
 			walker.setRevFilter(filter);
 
 			while (walker.next() != null) {
@@ -141,41 +141,105 @@ final class PackWriterBitmapWalker {
 		walker.reset();
 	}
 
-	static BitmapRevFilter newRevFilter(
-			final BitmapBuilder seen, final BitmapBuilder bitmapResult) {
+	static RevFilter newRevFilter(BitmapBuilder seen, BitmapBuilder bitmapResult) {
 		if (seen != null) {
-			return new BitmapRevFilter() {
-				protected boolean load(RevCommit cmit) {
-					if (seen.contains(cmit))
-						return false;
-					return bitmapResult.add(cmit, Constants.OBJ_COMMIT);
-				}
-			};
+			return new AddUnseenToBitmapFilter(seen, bitmapResult);
+		}
+		return new AddToBitmapFilter(bitmapResult);
+	}
+
+	/**
+	 * A RevFilter that adds the visited commits to {@code bitmap} as a side
+	 * effect.
+	 * <p>
+	 * When the walk hits a commit that is part of {@code bitmap}'s
+	 * BitmapIndex, that entire bitmap is ORed into {@code bitmap} and the
+	 * commit and its parents are marked as SEEN so that the walk does not
+	 * have to visit its ancestors.  This ensures the walk is very short if
+	 * there is good bitmap coverage.
+	 */
+	private static class AddToBitmapFilter extends RevFilter {
+		private final BitmapBuilder bitmap;
+
+		AddToBitmapFilter(BitmapBuilder bitmap) {
+			this.bitmap = bitmap;
 		}
-		return new BitmapRevFilter() {
-			@Override
-			protected boolean load(RevCommit cmit) {
-				return bitmapResult.add(cmit, Constants.OBJ_COMMIT);
+
+		@Override
+		public final boolean include(RevWalk walker, RevCommit cmit) {
+			Bitmap visitedBitmap;
+
+			if (bitmap.contains(cmit)) {
+				// already included
+			} else if ((visitedBitmap = bitmap.getBitmapIndex().getBitmap(cmit)) != null) {
+				bitmap.or(visitedBitmap);
+			} else {
+				bitmap.addObject(cmit, Constants.OBJ_COMMIT);
+				return true;
+			}
+
+			for (RevCommit p : cmit.getParents()) {
+				p.add(RevFlag.SEEN);
 			}
-		};
+			return false;
+		}
+
+		@Override
+		public final RevFilter clone() {
+			throw new UnsupportedOperationException();
+		}
+
+		@Override
+		public final boolean requiresCommitBody() {
+			return false;
+		}
 	}
 
-	static abstract class BitmapRevFilter extends RevFilter {
-		protected abstract boolean load(RevCommit cmit);
+	/**
+	 * A RevFilter that adds the visited commits to {@code bitmap} as a side
+	 * effect.
+	 * <p>
+	 * When the walk hits a commit that is part of {@code bitmap}'s
+	 * BitmapIndex, that entire bitmap is ORed into {@code bitmap} and the
+	 * commit and its parents are marked as SEEN so that the walk does not
+	 * have to visit its ancestors.  This ensures the walk is very short if
+	 * there is good bitmap coverage.
+	 * <p>
+	 * Commits named in {@code seen} are considered already seen.  If one is
+	 * encountered, that commit and its parents will be marked with the SEEN
+	 * flag to prevent the walk from visiting its ancestors.
+	 */
+	private static class AddUnseenToBitmapFilter extends RevFilter {
+		private final BitmapBuilder seen;
+		private final BitmapBuilder bitmap;
+
+		AddUnseenToBitmapFilter(BitmapBuilder seen, BitmapBuilder bitmapResult) {
+			this.seen = seen;
+			this.bitmap = bitmapResult;
+		}
 
 		@Override
 		public final boolean include(RevWalk walker, RevCommit cmit) {
-			if (load(cmit)) {
+			Bitmap visitedBitmap;
+
+			if (seen.contains(cmit) || bitmap.contains(cmit)) {
+				// already seen or included
+			} else if ((visitedBitmap = bitmap.getBitmapIndex().getBitmap(cmit)) != null) {
+				bitmap.or(visitedBitmap);
+			} else {
+				bitmap.addObject(cmit, Constants.OBJ_COMMIT);
 				return true;
 			}
-			for (RevCommit p : cmit.getParents())
+
+			for (RevCommit p : cmit.getParents()) {
 				p.add(RevFlag.SEEN);
+			}
 			return false;
 		}
 
 		@Override
 		public final RevFilter clone() {
-			return this;
+			throw new UnsupportedOperationException();
 		}
 
 		@Override