Enable writing pack indexes with bitmaps in the GC.

Update the dfs and file GC implementations to prepare and write
bitmaps on the packs that contain the full closure of the object
graph. Update the DfsPackDescription to include the index version.

Change-Id: I3f1421e9cd90fe93e7e2ef2b8179ae2f1ba819ed

org.eclipse.jgit/src/org/eclipse/jgit/storage/dfs/DfsGarbageCollector.java

@@ -45,6 +45,7 @@
 
 import static org.eclipse.jgit.storage.dfs.DfsObjDatabase.PackSource.GC;
 import static org.eclipse.jgit.storage.dfs.DfsObjDatabase.PackSource.UNREACHABLE_GARBAGE;
+import static org.eclipse.jgit.storage.pack.PackExt.BITMAP_INDEX;
 import static org.eclipse.jgit.storage.pack.PackExt.PACK;
 import static org.eclipse.jgit.storage.pack.PackExt.INDEX;
 
@@ -329,10 +330,22 @@ private DfsPackDescription writePack(PackSource source, PackWriter pw,
 			CountingOutputStream cnt = new CountingOutputStream(out);
 			pw.writeIndex(cnt);
 			pack.setFileSize(INDEX, cnt.getCount());
+			pack.setIndexVersion(pw.getIndexVersion());
 		} finally {
 			out.close();
 		}
 
+		if (pw.prepareBitmapIndex(pm)) {
+			out = objdb.writeFile(pack, BITMAP_INDEX);
+			try {
+				CountingOutputStream cnt = new CountingOutputStream(out);
+				pw.writeIndex(cnt);
+				pack.setFileSize(BITMAP_INDEX, cnt.getCount());
+			} finally {
+				out.close();
+			}
+		}
+
 		final ObjectIdOwnerMap<ObjectIdOwnerMap.Entry> packedObjs = pw
 				.getObjectSet();
 		newPackObj.add(new PackWriter.ObjectIdSet() {

org.eclipse.jgit/src/org/eclipse/jgit/storage/dfs/DfsInserter.java

@@ -240,6 +240,7 @@ private void sortObjectsById() {
 
 	PackIndex writePackIndex(DfsPackDescription pack, byte[] packHash,
 			List<PackedObjectInfo> list) throws IOException {
+		pack.setIndexVersion(INDEX_VERSION);
 		pack.setObjectCount(list.size());
 
 		// If there are less than 58,000 objects, the entire index fits in under

org.eclipse.jgit/src/org/eclipse/jgit/storage/dfs/DfsPackCompactor.java

@@ -303,6 +303,7 @@ private void writeIndex(DfsObjDatabase objdb, DfsPackDescription pack,
 			CountingOutputStream cnt = new CountingOutputStream(out);
 			pw.writeIndex(cnt);
 			pack.setFileSize(INDEX, cnt.getCount());
+			pack.setIndexVersion(pw.getIndexVersion());
 		} finally {
 			out.close();
 		}

org.eclipse.jgit/src/org/eclipse/jgit/storage/dfs/DfsPackDescription.java

@@ -81,6 +81,8 @@ public class DfsPackDescription implements Comparable<DfsPackDescription> {
 
 	private int extensions;
 
+	private int indexVersion;
+
 	/**
 	 * Initialize a description by pack name and repository.
 	 * <p>
@@ -259,6 +261,21 @@ public DfsPackDescription clearPackStats() {
 		return this;
 	}
 
+	/** @return the version of the index file written. */
+	public int getIndexVersion() {
+		return indexVersion;
+	}
+
+	/**
+	 * @param version
+	 *            the version of the index file written.
+	 * @return {@code this}
+	 */
+	public DfsPackDescription setIndexVersion(int version) {
+		indexVersion = version;
+		return this;
+	}
+
 	@Override
 	public int hashCode() {
 		return packName.hashCode();

org.eclipse.jgit/src/org/eclipse/jgit/storage/file/GC.java

@@ -43,6 +43,9 @@
  */
 package org.eclipse.jgit.storage.file;
 
+import static org.eclipse.jgit.storage.pack.PackExt.BITMAP_INDEX;
+import static org.eclipse.jgit.storage.pack.PackExt.INDEX;
+
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -54,6 +57,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -63,6 +67,7 @@
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.TreeMap;
 
 import org.eclipse.jgit.dircache.DirCacheIterator;
 import org.eclipse.jgit.errors.CorruptObjectException;
@@ -83,6 +88,7 @@
 import org.eclipse.jgit.revwalk.ObjectWalk;
 import org.eclipse.jgit.revwalk.RevObject;
 import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.jgit.storage.pack.PackExt;
 import org.eclipse.jgit.storage.pack.PackWriter;
 import org.eclipse.jgit.storage.pack.PackWriter.ObjectIdSet;
 import org.eclipse.jgit.treewalk.TreeWalk;
@@ -192,8 +198,10 @@ private void deleteOldPacks(Collection<PackFile> oldPacks,
 
 			if (!oldPack.shouldBeKept()) {
 				oldPack.close();
-				FileUtils.delete(nameFor(oldName, ".pack"), deleteOptions); //$NON-NLS-1$
-				FileUtils.delete(nameFor(oldName, ".idx"), deleteOptions); //$NON-NLS-1$
+				for (PackExt ext : PackExt.values()) {
+					File f = nameFor(oldName, "." + ext.getExtension()); //$NON-NLS-1$
+					FileUtils.delete(f, deleteOptions);
+				}
 			}
 		}
 		// close the complete object database. Thats my only chance to force
@@ -636,7 +644,22 @@ private PackFile writePack(Set<? extends ObjectId> want,
 			Set<? extends ObjectId> have, Set<ObjectId> tagTargets,
 			List<ObjectIdSet> excludeObjects) throws IOException {
 		File tmpPack = null;
-		File tmpIdx = null;
+		Map<PackExt, File> tmpExts = new TreeMap<PackExt, File>(
+				new Comparator<PackExt>() {
+					public int compare(PackExt o1, PackExt o2) {
+						// INDEX entries must be returned last, so the pack
+						// scanner does pick up the new pack until all the
+						// PackExt entries have been written.
+						if (o1 == o2)
+							return 0;
+						if (o1 == PackExt.INDEX)
+							return 1;
+						if (o2 == PackExt.INDEX)
+							return -1;
+						return Integer.signum(o1.hashCode() - o2.hashCode());
+					}
+
+				});
 		PackWriter pw = new PackWriter(repo);
 		try {
 			// prepare the PackWriter
@@ -655,9 +678,10 @@ private PackFile writePack(Set<? extends ObjectId> want,
 			String id = pw.computeName().getName();
 			File packdir = new File(repo.getObjectsDirectory(), "pack"); //$NON-NLS-1$
 			tmpPack = File.createTempFile("gc_", ".pack_tmp", packdir); //$NON-NLS-1$ //$NON-NLS-2$
-			tmpIdx = new File(packdir, tmpPack.getName().substring(0,
-					tmpPack.getName().lastIndexOf('.'))
-					+ ".idx_tmp"); //$NON-NLS-1$
+			final String tmpBase = tmpPack.getName()
+					.substring(0, tmpPack.getName().lastIndexOf('.'));
+			File tmpIdx = new File(packdir, tmpBase + ".idx_tmp"); //$NON-NLS-1$
+			tmpExts.put(INDEX, tmpIdx);
 
 			if (!tmpIdx.createNewFile())
 				throw new IOException(MessageFormat.format(
@@ -687,38 +711,70 @@ private PackFile writePack(Set<? extends ObjectId> want,
 				idxChannel.close();
 			}
 
+			if (pw.prepareBitmapIndex(pm)) {
+				File tmpBitmapIdx = new File(packdir, tmpBase + ".bitmap_tmp"); //$NON-NLS-1$
+				tmpExts.put(BITMAP_INDEX, tmpBitmapIdx);
+
+				if (!tmpBitmapIdx.createNewFile())
+					throw new IOException(MessageFormat.format(
+							JGitText.get().cannotCreateIndexfile,
+							tmpBitmapIdx.getPath()));
+
+				idxChannel = new FileOutputStream(tmpBitmapIdx).getChannel();
+				idxStream = Channels.newOutputStream(idxChannel);
+				try {
+					pw.writeBitmapIndex(idxStream);
+				} finally {
+					idxChannel.force(true);
+					idxStream.close();
+					idxChannel.close();
+				}
+			}
+
 			// rename the temporary files to real files
 			File realPack = nameFor(id, ".pack"); //$NON-NLS-1$
 			tmpPack.setReadOnly();
-			File realIdx = nameFor(id, ".idx"); //$NON-NLS-1$
-			realIdx.setReadOnly();
 			boolean delete = true;
 			try {
 				if (!tmpPack.renameTo(realPack))
 					return null;
 				delete = false;
-				if (!tmpIdx.renameTo(realIdx)) {
-					File newIdx = new File(realIdx.getParentFile(),
-							realIdx.getName() + ".new"); //$NON-NLS-1$
-					if (!tmpIdx.renameTo(newIdx))
-						newIdx = tmpIdx;
-					throw new IOException(MessageFormat.format(
-							JGitText.get().panicCantRenameIndexFile, newIdx,
-							realIdx));
+				for (Map.Entry<PackExt, File> tmpEntry : tmpExts.entrySet()) {
+					File tmpExt = tmpEntry.getValue();
+					tmpExt.setReadOnly();
+
+					File realExt = nameFor(
+							id, "." + tmpEntry.getKey().getExtension()); //$NON-NLS-1$
+					if (!tmpExt.renameTo(realExt)) {
+						File newExt = new File(realExt.getParentFile(),
+								realExt.getName() + ".new"); //$NON-NLS-1$
+						if (!tmpExt.renameTo(newExt))
+							newExt = tmpExt;
+						throw new IOException(MessageFormat.format(
+								JGitText.get().panicCantRenameIndexFile, newExt,
+								realExt));
+					}
 				}
+
 			} finally {
-				if (delete && tmpPack.exists())
-					tmpPack.delete();
-				if (delete && tmpIdx.exists())
-					tmpIdx.delete();
+				if (delete) {
+					if (tmpPack.exists())
+						tmpPack.delete();
+					for (File tmpExt : tmpExts.values()) {
+						if (tmpExt.exists())
+							tmpExt.delete();
+					}
+				}
 			}
 			return repo.getObjectDatabase().openPack(realPack);
 		} finally {
 			pw.release();
 			if (tmpPack != null && tmpPack.exists())
 				tmpPack.delete();
-			if (tmpIdx != null && tmpIdx.exists())
-				tmpIdx.delete();
+			for (File tmpExt : tmpExts.values()) {
+				if (tmpExt.exists())
+					tmpExt.delete();
+			}
 		}
 	}
 

org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackWriter.java

@@ -866,7 +866,7 @@ public void writeIndex(final OutputStream indexStream) throws IOException {
 	 * Create a bitmap index file to match the pack file just written.
 	 * <p>
 	 * This method can only be invoked after
-	 * {@link #prepareBitmapIndex(ProgressMonitor, Set)} has been invoked and
+	 * {@link #prepareBitmapIndex(ProgressMonitor)} has been invoked and
 	 * completed successfully. Writing a corresponding bitmap index is an
 	 * optional feature that not all pack users may require.
 	 *
@@ -2051,16 +2051,11 @@ private final boolean have(ObjectToPack ptr, AnyObjectId objectId) {
 	 *
 	 * @param pm
 	 *            progress monitor to report bitmap building work.
-	 * @param want
-	 *            collection of objects to be marked as interesting (start
-	 *            points of graph traversal).
 	 * @return whether a bitmap index may be written.
 	 * @throws IOException
 	 *             when some I/O problem occur during reading objects.
 	 */
-	public boolean prepareBitmapIndex(
-			ProgressMonitor pm, Set<? extends ObjectId> want)
-			throws IOException {
+	public boolean prepareBitmapIndex(ProgressMonitor pm) throws IOException {
 		if (!canBuildBitmaps || getObjectCount() > Integer.MAX_VALUE
 				|| !cachedPacks.isEmpty())
 			return false;
@@ -2069,8 +2064,8 @@ public boolean prepareBitmapIndex(
 			pm = NullProgressMonitor.INSTANCE;
 
 		writeBitmaps = new PackBitmapIndexBuilder(sortByName());
-		PackWriterBitmapPreparer bitmapPreparer =
-				new PackWriterBitmapPreparer(reader, writeBitmaps, pm, want);
+		PackWriterBitmapPreparer bitmapPreparer = new PackWriterBitmapPreparer(
+				reader, writeBitmaps, pm, stats.interestingObjects);
 
 		int numCommits = objectsLists[Constants.OBJ_COMMIT].size();
 		Collection<PackWriterBitmapPreparer.BitmapCommit> selectedCommits =