Merge changes Ifc8fc3e5,I7c403b50

* changes:
  Remove packIndex field from FileObjDatabase openPack method.
  Update DfsObjDatabase API to open/write by pack extension.

org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java

@@ -667,7 +667,7 @@ public class TestRepository<R extends Repository> {
 				pw.release();
 			}
 
-			odb.openPack(pack, idx);
+			odb.openPack(pack);
 			updateServerInfo();
 			prunePacked(odb);
 		}

org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/PackWriterTest.java

@@ -298,7 +298,7 @@ public class PackWriterTest extends SampleDataRepositoryTestCase {
 		copyFile(JGitTestUtil.getTestResourceFile(
 				"pack-34be9032ac282b11fa9babdc2b2a93ca996c9c2f.idxV2"),
 				crc32Idx);
-		db.openPack(crc32Pack, crc32Idx);
+		db.openPack(crc32Pack);
 
 		writeVerifyPack2(true);
 	}

org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/T0004_PackReaderTest.java

@@ -62,7 +62,6 @@ import org.junit.Test;
 public class T0004_PackReaderTest extends SampleDataRepositoryTestCase {
 	private static final String PACK_NAME = "pack-34be9032ac282b11fa9babdc2b2a93ca996c9c2f";
 	private static final File TEST_PACK = JGitTestUtil.getTestResourceFile(PACK_NAME + ".pack");
-	private static final File TEST_IDX = JGitTestUtil.getTestResourceFile(PACK_NAME + ".idx");
 
 	@Test
 	public void test003_lookupCompressedObject() throws IOException {
@@ -71,7 +70,7 @@ public class T0004_PackReaderTest extends SampleDataRepositoryTestCase {
 		final ObjectLoader or;
 
 		id = ObjectId.fromString("902d5476fa249b7abc9d84c611577a81381f0327");
-		pr = new PackFile(TEST_IDX, TEST_PACK);
+		pr = new PackFile(TEST_PACK);
 		or = pr.get(new WindowCursor(null), id);
 		assertNotNull(or);
 		assertEquals(Constants.OBJ_TREE, or.getType());

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

@@ -65,6 +65,7 @@ import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.storage.dfs.DfsObjDatabase.PackSource;
 import org.eclipse.jgit.storage.file.PackIndex;
 import org.eclipse.jgit.storage.pack.PackConfig;
+import org.eclipse.jgit.storage.pack.PackConstants;
 import org.eclipse.jgit.storage.pack.PackWriter;
 import org.eclipse.jgit.util.io.CountingOutputStream;
 
@@ -318,14 +319,14 @@ public class DfsGarbageCollector {
 		DfsPackDescription pack = repo.getObjectDatabase().newPack(source);
 		newPackDesc.add(pack);
 
-		out = objdb.writePackFile(pack);
+		out = objdb.writeFile(pack, PackConstants.PACK_EXT);
 		try {
 			pw.writePack(pm, pm, out);
 		} finally {
 			out.close();
 		}
 
-		out = objdb.writePackIndex(pack);
+		out = objdb.writeFile(pack, PackConstants.PACK_INDEX_EXT);
 		try {
 			CountingOutputStream cnt = new CountingOutputStream(out);
 			pw.writeIndex(cnt);

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

@@ -43,6 +43,9 @@
 
 package org.eclipse.jgit.storage.dfs;
 
+import static org.eclipse.jgit.storage.pack.PackConstants.PACK_EXT;
+import static org.eclipse.jgit.storage.pack.PackConstants.PACK_INDEX_EXT;
+
 import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
@@ -220,7 +223,7 @@ public class DfsInserter extends ObjectInserter {
 
 		rollback = true;
 		packDsc = db.newPack(DfsObjDatabase.PackSource.INSERT);
-		packOut = new PackStream(db.writePackFile(packDsc));
+		packOut = new PackStream(db.writeFile(packDsc, PACK_EXT));
 		packKey = new DfsPackKey();
 
 		// Write the header as though it were a single object pack.
@@ -250,7 +253,7 @@ public class DfsInserter extends ObjectInserter {
 			packIndex = PackIndex.read(buf.openInputStream());
 		}
 
-		DfsOutputStream os = db.writePackIndex(pack);
+		DfsOutputStream os = db.writeFile(pack, PACK_INDEX_EXT);
 		try {
 			CountingOutputStream cnt = new CountingOutputStream(os);
 			if (buf != null)

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

@@ -264,62 +264,40 @@ public abstract class DfsObjDatabase extends ObjectDatabase {
 	protected abstract List<DfsPackDescription> listPacks() throws IOException;
 
 	/**
-	 * Open a pack file for reading.
+	 * Open a pack, pack index, or other related file for reading.
 	 *
 	 * @param desc
-	 *            description of pack to read. This is an instance previously
-	 *            obtained from {@link #listPacks()}, but not necessarily from
-	 *            the same DfsObjDatabase instance.
-	 * @return channel to read the pack file.
+	 *            description of pack related to the data that will be read.
+	 *            This is an instance previously obtained from
+	 *            {@link #listPacks()}, but not necessarily from the same
+	 *            DfsObjDatabase instance.
+	 * @param ext
+	 *            file extension that will be read i.e "pack" or "idx".
+	 * @return channel to read the file.
 	 * @throws FileNotFoundException
 	 *             the file does not exist.
 	 * @throws IOException
 	 *             the file cannot be opened.
 	 */
-	protected abstract ReadableChannel openPackFile(DfsPackDescription desc)
+	protected abstract ReadableChannel openFile(
+			DfsPackDescription desc, String ext)
 			throws FileNotFoundException, IOException;
 
 	/**
-	 * Open a pack index for reading.
+	 * Open a pack, pack index, or other related file for writing.
 	 *
 	 * @param desc
-	 *            description of index to read. This is an instance previously
-	 *            obtained from {@link #listPacks()}, but not necessarily from
-	 *            the same DfsObjDatabase instance.
-	 * @return channel to read the pack file.
-	 * @throws FileNotFoundException
-	 *             the file does not exist.
-	 * @throws IOException
-	 *             the file cannot be opened.
-	 */
-	protected abstract ReadableChannel openPackIndex(DfsPackDescription desc)
-			throws FileNotFoundException, IOException;
-
-	/**
-	 * Open a pack file for writing.
-	 *
-	 * @param desc
-	 *            description of pack to write. This is an instance previously
-	 *            obtained from {@link #newPack(PackSource)}.
-	 * @return channel to write the pack file.
+	 *            description of pack related to the data that will be written.
+	 *            This is an instance previously obtained from
+	 *            {@link #newPack(PackSource)}.
+	 * @param ext
+	 *            file extension that will be written i.e "pack" or "idx".
+	 * @return channel to write the file.
 	 * @throws IOException
 	 *             the file cannot be opened.
 	 */
-	protected abstract DfsOutputStream writePackFile(DfsPackDescription desc)
-			throws IOException;
-
-	/**
-	 * Open a pack index for writing.
-	 *
-	 * @param desc
-	 *            description of index to write. This is an instance previously
-	 *            obtained from {@link #newPack(PackSource)}.
-	 * @return channel to write the index file.
-	 * @throws IOException
-	 *             the file cannot be opened.
-	 */
-	protected abstract DfsOutputStream writePackIndex(DfsPackDescription desc)
-			throws IOException;
+	protected abstract DfsOutputStream writeFile(
+			DfsPackDescription desc, String ext) throws IOException;
 
 	void addPack(DfsPackFile newPack) throws IOException {
 		PackList o, n;

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

@@ -50,8 +50,7 @@ import java.nio.ByteBuffer;
 /**
  * Output stream to create a file on the DFS.
  *
- * @see DfsObjDatabase#writePackFile(DfsPackDescription)
- * @see DfsObjDatabase#writePackIndex(DfsPackDescription)
+ * @see DfsObjDatabase#writeFile(DfsPackDescription, String)
  */
 public abstract class DfsOutputStream extends OutputStream {
 	/**

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

@@ -44,6 +44,8 @@
 package org.eclipse.jgit.storage.dfs;
 
 import static org.eclipse.jgit.storage.dfs.DfsObjDatabase.PackSource.COMPACT;
+import static org.eclipse.jgit.storage.pack.PackConstants.PACK_EXT;
+import static org.eclipse.jgit.storage.pack.PackConstants.PACK_INDEX_EXT;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -283,7 +285,7 @@ public class DfsPackCompactor {
 
 	private void writePack(DfsObjDatabase objdb, DfsPackDescription pack,
 			PackWriter pw, ProgressMonitor pm) throws IOException {
-		DfsOutputStream out = objdb.writePackFile(pack);
+		DfsOutputStream out = objdb.writeFile(pack, PACK_EXT);
 		try {
 			CountingOutputStream cnt = new CountingOutputStream(out);
 			pw.writePack(pm, pm, cnt);
@@ -296,7 +298,7 @@ public class DfsPackCompactor {
 
 	private void writeIndex(DfsObjDatabase objdb, DfsPackDescription pack,
 			PackWriter pw) throws IOException {
-		DfsOutputStream out = objdb.writePackIndex(pack);
+		DfsOutputStream out = objdb.writeFile(pack, PACK_INDEX_EXT);
 		try {
 			CountingOutputStream cnt = new CountingOutputStream(out);
 			pw.writeIndex(cnt);

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

@@ -47,6 +47,7 @@ import java.util.Set;
 
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.storage.dfs.DfsObjDatabase.PackSource;
+import org.eclipse.jgit.storage.pack.PackConstants;
 import org.eclipse.jgit.storage.pack.PackWriter;
 
 /**
@@ -81,9 +82,9 @@ public class DfsPackDescription implements Comparable<DfsPackDescription> {
 	/**
 	 * Initialize a description by pack name and repository.
 	 * <p>
-	 * The corresponding index file is assumed to exist and end with ".idx"
-	 * instead of ".pack". If this is not true implementors must extend the
-	 * class and override {@link #getIndexName()}.
+	 * The corresponding index file is assumed to exist. If this is not true
+	 * implementors must extend the class and override
+	 * {@link #getFileName(String)}.
 	 * <p>
 	 * Callers should also try to fill in other fields if they are reasonably
 	 * free to access at the time this instance is being initialized.
@@ -95,7 +96,8 @@ public class DfsPackDescription implements Comparable<DfsPackDescription> {
 	 */
 	public DfsPackDescription(DfsRepositoryDescription repoDesc, String name) {
 		this.repoDesc = repoDesc;
-		this.packName = name;
+		int dot = name.lastIndexOf('.');
+		this.packName = (dot < 0) ? name : name.substring(0, dot);
 	}
 
 	/** @return description of the repository. */
@@ -103,18 +105,13 @@ public class DfsPackDescription implements Comparable<DfsPackDescription> {
 		return repoDesc;
 	}
 
-	/** @return name of the pack file. */
-	public String getPackName() {
-		return packName;
-	}
-
-	/** @return name of the index file. */
-	public String getIndexName() {
-		String name = getPackName();
-		int dot = name.lastIndexOf('.');
-		if (dot < 0)
-			dot = name.length();
-		return name.substring(0, dot) + ".idx"; //$NON-NLS-1$
+	/**
+	 * @param ext
+	 *            the file extension
+	 * @return name of the file.
+	 * */
+	public String getFileName(String ext) {
+		return packName + '.' + ext;
 	}
 
 	/** @return the source of the pack. */
@@ -261,14 +258,14 @@ public class DfsPackDescription implements Comparable<DfsPackDescription> {
 
 	@Override
 	public int hashCode() {
-		return getPackName().hashCode();
+		return packName.hashCode();
 	}
 
 	@Override
 	public boolean equals(Object b) {
 		if (b instanceof DfsPackDescription) {
 			DfsPackDescription desc = (DfsPackDescription) b;
-			return getPackName().equals(desc.getPackName()) &&
+			return packName.equals(desc.packName) &&
 					getRepositoryDescription().equals(desc.getRepositoryDescription());
 		}
 		return false;
@@ -299,6 +296,6 @@ public class DfsPackDescription implements Comparable<DfsPackDescription> {
 
 	@Override
 	public String toString() {
-		return getPackName();
+		return getFileName(PackConstants.PACK_EXT);
 	}
 }

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

@@ -45,6 +45,9 @@
 
 package org.eclipse.jgit.storage.dfs;
 
+import static org.eclipse.jgit.storage.pack.PackConstants.PACK_EXT;
+import static org.eclipse.jgit.storage.pack.PackConstants.PACK_INDEX_EXT;
+
 import java.io.BufferedInputStream;
 import java.io.EOFException;
 import java.io.IOException;
@@ -187,7 +190,7 @@ public final class DfsPackFile {
 	}
 
 	private String getPackName() {
-		return packDesc.getPackName();
+		return packDesc.getFileName(PACK_EXT);
 	}
 
 	void setBlockSize(int newSize) {
@@ -229,7 +232,7 @@ public final class DfsPackFile {
 
 			PackIndex idx;
 			try {
-				ReadableChannel rc = ctx.db.openPackIndex(packDesc);
+				ReadableChannel rc = ctx.db.openFile(packDesc, PACK_INDEX_EXT);
 				try {
 					InputStream in = Channels.newInputStream(rc);
 					int wantSize = 8192;
@@ -246,13 +249,15 @@ public final class DfsPackFile {
 			} catch (EOFException e) {
 				invalid = true;
 				IOException e2 = new IOException(MessageFormat.format(
-						DfsText.get().shortReadOfIndex, packDesc.getIndexName()));
+						DfsText.get().shortReadOfIndex,
+						packDesc.getFileName(PACK_INDEX_EXT)));
 				e2.initCause(e);
 				throw e2;
 			} catch (IOException e) {
 				invalid = true;
 				IOException e2 = new IOException(MessageFormat.format(
-						DfsText.get().cannotReadIndex, packDesc.getIndexName()));
+						DfsText.get().cannotReadIndex,
+						packDesc.getFileName(PACK_INDEX_EXT)));
 				e2.initCause(e);
 				throw e2;
 			}
@@ -616,7 +621,7 @@ public final class DfsPackFile {
 			throw new PackInvalidException(getPackName());
 
 		boolean close = true;
-		ReadableChannel rc = ctx.db.openPackFile(packDesc);
+		ReadableChannel rc = ctx.db.openFile(packDesc, PACK_EXT);
 		try {
 			// If the block alignment is not yet known, discover it. Prefer the
 			// larger size from either the cache or the file itself.

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

@@ -58,6 +58,7 @@ import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ProgressMonitor;
 import org.eclipse.jgit.storage.file.PackIndex;
 import org.eclipse.jgit.storage.file.PackLock;
+import org.eclipse.jgit.storage.pack.PackConstants;
 import org.eclipse.jgit.transport.PackParser;
 import org.eclipse.jgit.transport.PackedObjectInfo;
 
@@ -205,7 +206,7 @@ public class DfsPackParser extends PackParser {
 		packDsc = objdb.newPack(DfsObjDatabase.PackSource.RECEIVE);
 		packKey = new DfsPackKey();
 
-		out = objdb.writePackFile(packDsc);
+		out = objdb.writeFile(packDsc, PackConstants.PACK_EXT);
 		int size = out.blockSize();
 		if (size <= 0)
 			size = blockCache.getBlockSize();

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

@@ -47,6 +47,7 @@ package org.eclipse.jgit.storage.dfs;
 import static org.eclipse.jgit.lib.Constants.OBJECT_ID_LENGTH;
 import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
 import static org.eclipse.jgit.lib.Constants.OBJ_TREE;
+import static org.eclipse.jgit.storage.pack.PackConstants.PACK_EXT;
 
 import java.io.IOException;
 import java.io.InterruptedIOException;
@@ -661,7 +662,7 @@ public final class DfsReader extends ObjectReader implements ObjectReuseAsIs {
 				pack.setInvalid();
 				throw new IOException(MessageFormat.format(
 						JGitText.get().packfileCorruptionDetected,
-						pack.getPackDescription().getPackName()));
+						pack.getPackDescription().getFileName(PACK_EXT)));
 			}
 		}
 	}

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

@@ -6,7 +6,9 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -101,50 +103,31 @@ public class InMemoryRepository extends DfsRepository {
 		}
 
 		@Override
-		protected ReadableChannel openPackFile(DfsPackDescription desc)
-				throws FileNotFoundException {
+		protected ReadableChannel openFile(DfsPackDescription desc, String ext)
+				throws FileNotFoundException, IOException {
 			MemPack memPack = (MemPack) desc;
-			if (memPack.packFile == null)
-				throw new FileNotFoundException(desc.getPackName());
-			return new ByteArrayReadableChannel(memPack.packFile);
+			byte[] file = memPack.fileMap.get(ext);
+			if (file == null)
+				throw new FileNotFoundException(desc.getFileName(ext));
+			return new ByteArrayReadableChannel(file);
 		}
 
 		@Override
-		protected ReadableChannel openPackIndex(DfsPackDescription desc)
-				throws FileNotFoundException {
-			MemPack memPack = (MemPack) desc;
-			if (memPack.packIndex == null)
-				throw new FileNotFoundException(desc.getIndexName());
-			return new ByteArrayReadableChannel(memPack.packIndex);
-		}
-
-		@Override
-		protected DfsOutputStream writePackFile(DfsPackDescription desc) {
-			final MemPack memPack = (MemPack) desc;
-			return new Out() {
-				@Override
-				public void flush() {
-					memPack.packFile = getData();
-				}
-			};
-		}
-
-		@Override
-		protected DfsOutputStream writePackIndex(DfsPackDescription desc) {
+		protected DfsOutputStream writeFile(
+				DfsPackDescription desc, final String ext) throws IOException {
 			final MemPack memPack = (MemPack) desc;
 			return new Out() {
 				@Override
 				public void flush() {
-					memPack.packIndex = getData();
+					memPack.fileMap.put(ext, getData());
 				}
 			};
 		}
 	}
 
 	private static class MemPack extends DfsPackDescription {
-		private byte[] packFile;
-
-		private byte[] packIndex;
+		private final Map<String, byte[]>
+				fileMap = new HashMap<String, byte[]>();
 
 		MemPack(String name, DfsRepositoryDescription repoDesc) {
 			super(repoDesc, name);

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

@@ -252,8 +252,8 @@ class CachedObjectDirectory extends FileObjectDatabase {
 	}
 
 	@Override
-	PackFile openPack(File pack, File idx) throws IOException {
-		return wrapped.openPack(pack, idx);
+	PackFile openPack(File pack) throws IOException {
+		return wrapped.openPack(pack);
 	}
 
 	@Override

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

@@ -288,7 +288,7 @@ abstract class FileObjectDatabase extends ObjectDatabase {
 	abstract InsertLooseObjectResult insertUnpackedObject(File tmp,
 			ObjectId id, boolean createDuplicate) throws IOException;
 
-	abstract PackFile openPack(File pack, File idx) throws IOException;
+	abstract PackFile openPack(File pack) throws IOException;
 
 	abstract FileObjectDatabase newCachedFileObjectDatabase();
 

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

@@ -369,14 +369,12 @@ public class FileRepository extends Repository {
 	 *
 	 * @param pack
 	 *            path of the pack file to open.
-	 * @param idx
-	 *            path of the corresponding index file.
 	 * @throws IOException
 	 *             index file could not be opened, read, or is not recognized as
 	 *             a Git pack file index.
 	 */
-	public void openPack(final File pack, final File idx) throws IOException {
-		objectDatabase.openPack(pack, idx);
+	public void openPack(final File pack) throws IOException {
+		objectDatabase.openPack(pack);
 	}
 
 	@Override

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

@@ -710,7 +710,7 @@ public class GC {
 				if (delete && tmpIdx.exists())
 					tmpIdx.delete();
 			}
-			return repo.getObjectDatabase().openPack(realPack, realIdx);
+			return repo.getObjectDatabase().openPack(realPack);
 		} finally {
 			pw.release();
 			if (tmpPack != null && tmpPack.exists())

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

@@ -327,28 +327,18 @@ public class ObjectDirectory extends FileObjectDatabase {
 	 *
 	 * @param pack
 	 *            path of the pack file to open.
-	 * @param idx
-	 *            path of the corresponding index file.
 	 * @return the pack that was opened and added to the database.
 	 * @throws IOException
 	 *             index file could not be opened, read, or is not recognized as
 	 *             a Git pack file index.
 	 */
-	public PackFile openPack(final File pack, final File idx)
+	public PackFile openPack(final File pack)
 			throws IOException {
 		final String p = pack.getName();
-		final String i = idx.getName();
-
 		if (p.length() != 50 || !p.startsWith("pack-") || !p.endsWith(".pack")) //$NON-NLS-1$
 			throw new IOException(MessageFormat.format(JGitText.get().notAValidPack, pack));
 
-		if (i.length() != 49 || !i.startsWith("pack-") || !i.endsWith(".idx")) //$NON-NLS-1$
-			throw new IOException(MessageFormat.format(JGitText.get().notAValidPack, idx));
-
-		if (!p.substring(0, 45).equals(i.substring(0, 45)))
-			throw new IOException(MessageFormat.format(JGitText.get().packDoesNotMatchIndex, pack));
-
-		PackFile res = new PackFile(idx, pack);
+		PackFile res = new PackFile(pack);
 		insertPack(res);
 		return res;
 	}
@@ -747,8 +737,7 @@ public class ObjectDirectory extends FileObjectDatabase {
 			}
 
 			final File packFile = new File(packDirectory, packName);
-			final File idxFile = new File(packDirectory, indexName);
-			list.add(new PackFile(idxFile, packFile));
+			list.add(new PackFile(packFile));
 			foundNew = true;
 		}
 

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

@@ -479,7 +479,7 @@ public class ObjectDirectoryPackParser extends PackParser {
 		}
 
 		try {
-			newPack = db.openPack(finalPack, finalIdx);
+			newPack = db.openPack(finalPack);
 		} catch (IOException err) {
 			keep.unlock();
 			if (finalPack.exists())

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

@@ -45,6 +45,8 @@
 
 package org.eclipse.jgit.storage.file;
 
+import static org.eclipse.jgit.storage.pack.PackConstants.PACK_INDEX_EXT;
+
 import java.io.EOFException;
 import java.io.File;
 import java.io.IOException;
@@ -92,8 +94,6 @@ public class PackFile implements Iterable<PackIndex.MutableEntry> {
 		}
 	};
 
-	private final File idxFile;
-
 	private final File packFile;
 
 	private File keepFile;
@@ -135,13 +135,10 @@ public class PackFile implements Iterable<PackIndex.MutableEntry> {
 	/**
 	 * Construct a reader for an existing, pre-indexed packfile.
 	 *
-	 * @param idxFile
-	 *            path of the <code>.idx</code> file listing the contents.
 	 * @param packFile
 	 *            path of the <code>.pack</code> file holding the data.
 	 */
-	public PackFile(final File idxFile, final File packFile) {
-		this.idxFile = idxFile;
+	public PackFile(final File packFile) {
 		this.packFile = packFile;
 		this.packLastModified = (int) (packFile.lastModified() >> 10);
 
@@ -158,7 +155,7 @@ public class PackFile implements Iterable<PackIndex.MutableEntry> {
 				throw new PackInvalidException(packFile);
 
 			try {
-				final PackIndex idx = PackIndex.open(idxFile);
+				final PackIndex idx = PackIndex.open(extFile(PACK_INDEX_EXT));
 
 				if (packChecksum == null)
 					packChecksum = idx.packChecksum;
@@ -1080,4 +1077,11 @@ public class PackFile implements Iterable<PackIndex.MutableEntry> {
 			list.add(offset);
 		}
 	}
+
+	private File extFile(String ext) {
+		String p = packFile.getName();
+		int dot = p.lastIndexOf('.');
+		String b = (dot < 0) ? p : p.substring(0, dot);
+		return new File(packFile.getParentFile(), b + '.' + ext);
+	}
 }

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

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2013, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.storage.pack;
+
+/** Misc. constants used with pack files. */
+public class PackConstants {
+
+	/** A pack file extension. */
+	public static final String PACK_EXT = "pack"; //$NON-NLS-1$
+
+	/** A pack index file extension. */
+	public static final String PACK_INDEX_EXT = "idx"; //$NON-NLS-1$
+
+	private PackConstants() {
+	}
+}