DfsPackFileMidx: Offer localIterator

We need the iterator to use an exiting midx as input to write a new
one.

Add a localIterator() method to get the iterator over local objects.

Change-Id: Ie5037639dbec0abc8af8a6e195aa5c756a6a6964

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidx.java

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidx.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidx.java
index 0582737..3c63db2 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidx.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidx.java
@@ -20,6 +20,7 @@
 import org.eclipse.jgit.errors.StoredObjectRepresentationNotAvailableException;
 import org.eclipse.jgit.internal.storage.file.PackIndex;
 import org.eclipse.jgit.internal.storage.file.PackReverseIndex;
+import org.eclipse.jgit.internal.storage.midx.MultiPackIndex;
 import org.eclipse.jgit.internal.storage.pack.ObjectToPack;
 import org.eclipse.jgit.internal.storage.pack.PackOutputStream;
 import org.eclipse.jgit.lib.AbbreviatedObjectId;
@@ -152,6 +153,18 @@ protected int getObjectCount(DfsReader ctx) throws IOException {
 	 */
 	protected abstract byte[] getChecksum(DfsReader ctx) throws IOException;
 
+	/**
+	 * Get a midx iterator over the contents of *this* midx, without the base.
+	 *
+	 * @param ctx
+	 *            a ready
+	 * @return an iterator over the objects in this midx in sha1 order
+	 * @throws IOException
+	 *             an error loading the underlying data
+	 */
+	protected abstract MultiPackIndex.MidxIterator localIterator(DfsReader ctx)
+			throws IOException;
+
 	@Override
 	public final PackIndex getPackIndex(DfsReader ctx) {
 		return new MidxPackIndex(this, ctx);

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxNPacks.java

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxNPacks.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxNPacks.java
index bed7a53..7b030cf 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxNPacks.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxNPacks.java
@@ -242,6 +242,12 @@ protected int getObjectCount(DfsReader ctx) throws IOException {
 		return midx(ctx).getChecksum();
 	}
 
+	@Override
+	protected MultiPackIndex.MidxIterator localIterator(DfsReader ctx)
+			throws IOException {
+		return midx(ctx).iterator();
+	}
+
 	/**
 	 * Packs indexed by this multipack index (base NOT included)
 	 *

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxSingle.java

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxSingle.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxSingle.java
index 71ff884..89dbf9d 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxSingle.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFileMidxSingle.java
@@ -25,6 +25,8 @@
 import org.eclipse.jgit.internal.storage.file.PackBitmapIndex;
 import org.eclipse.jgit.internal.storage.file.PackIndex;
 import org.eclipse.jgit.internal.storage.file.PackReverseIndex;
+import org.eclipse.jgit.internal.storage.midx.MidxIterators;
+import org.eclipse.jgit.internal.storage.midx.MultiPackIndex;
 import org.eclipse.jgit.internal.storage.midx.MultiPackIndex.PackOffset;
 import org.eclipse.jgit.internal.storage.pack.ObjectToPack;
 import org.eclipse.jgit.internal.storage.pack.PackExt;
@@ -149,6 +151,14 @@ protected int getObjectCount(DfsReader ctx) throws IOException {
 		return checksum;
 	}
 
+	@Override
+	protected MultiPackIndex.MidxIterator localIterator(DfsReader ctx)
+			throws IOException {
+		String packName = pack.getPackDescription().getPackName();
+		PackIndex packIndex = pack.getPackIndex(ctx);
+		return MidxIterators.fromPackIndexIterator(packName, packIndex);
+	}
+
 	/**
 	 * Packs indexed by this multipack index (base NOT included)
 	 *