org.eclipse.jgit.internal.storage.file

Class PackIndexV2

java.lang.Object

org.eclipse.jgit.internal.storage.file.PackIndex

org.eclipse.jgit.internal.storage.file.PackIndexV2

All Implemented Interfaces:

java.lang.Iterable<PackIndex.MutableEntry>, ObjectIdSet

class PackIndexV2
extends PackIndex

Support for the pack index v2 format.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	PackIndexV2.EntriesIteratorV2

Nested classes/interfaces inherited from class org.eclipse.jgit.internal.storage.file.PackIndex

PackIndex.EntriesIterator, PackIndex.MutableEntry

Field Summary

Fields

Modifier and Type	Field and Description
private byte[][]	crc32 256 arrays of the CRC-32 of objects, matching names.
private static int	FANOUT
private long[]	fanoutTable
private static long	IS_O64
(package private) int[][]	names 256 arrays of contiguous object names.
private static byte[]	NO_BYTES
private static int[]	NO_INTS
private long	objectCnt
(package private) byte[][]	offset32 256 arrays of the 32 bit offset data, matching names.
(package private) byte[]	offset64 64 bit offset table.

Fields inherited from class org.eclipse.jgit.internal.storage.file.PackIndex

packChecksum

Constructor Summary

Constructors

Constructor and Description
PackIndexV2(java.io.InputStream fd)

Method Summary

Modifier and Type	Method and Description
private int	binarySearchLevelTwo(AnyObjectId objId, int levelOne)
long	findCRC32(AnyObjectId objId) Retrieve stored CRC32 checksum of the requested object raw-data (including header).
private int	findLevelOne(long nthPosition)
long	findOffset(AnyObjectId objId) Locate the file offset position for the requested object.
private int	getLevelTwo(long nthPosition, int levelOne)
long	getObjectCount() Obtain the total number of objects described by this index.
ObjectId	getObjectId(long nthPosition) Get ObjectId for the n-th object entry returned by PackIndex.iterator().
private long	getOffset(int levelOne, int levelTwo)
long	getOffset(long nthPosition) Get offset in a pack for the n-th object entry returned by PackIndex.iterator().
long	getOffset64Count() Obtain the total number of objects needing 64 bit offsets.
boolean	hasCRC32Support() Check whether this index supports (has) CRC32 checksums for objects.
private static int	idOffset(int p)
java.util.Iterator<PackIndex.MutableEntry>	iterator()
void	resolve(java.util.Set<ObjectId> matches, AbbreviatedObjectId id, int matchLimit) Find objects matching the prefix abbreviation.

Methods inherited from class org.eclipse.jgit.internal.storage.file.PackIndex

contains, getObjectId, hasObject, open, read

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

IS_O64

private static final long IS_O64

See Also:

Constant Field Values

FANOUT

private static final int FANOUT

See Also:

Constant Field Values

NO_INTS

private static final int[] NO_INTS

NO_BYTES

private static final byte[] NO_BYTES

objectCnt

private long objectCnt

fanoutTable

private final long[] fanoutTable

names

int[][] names

256 arrays of contiguous object names.

offset32

byte[][] offset32

256 arrays of the 32 bit offset data, matching names.

crc32

private byte[][] crc32

256 arrays of the CRC-32 of objects, matching names.

offset64

byte[] offset64

64 bit offset table.

Constructor Detail

PackIndexV2

PackIndexV2(java.io.InputStream fd)
     throws java.io.IOException

Throws:

java.io.IOException

Method Detail

getObjectCount

public long getObjectCount()

Obtain the total number of objects described by this index.

Specified by:

getObjectCount in class PackIndex

Returns:

number of objects in this index, and likewise in the associated pack that this index was generated from.

getOffset64Count

public long getOffset64Count()

Obtain the total number of objects needing 64 bit offsets.

Specified by:

getOffset64Count in class PackIndex

Returns:

number of objects in this index using a 64 bit offset; that is an object positioned after the 2 GB position within the file.

findLevelOne

private int findLevelOne(long nthPosition)

getLevelTwo

private int getLevelTwo(long nthPosition,
                        int levelOne)

getObjectId

public ObjectId getObjectId(long nthPosition)

Get ObjectId for the n-th object entry returned by PackIndex.iterator().

This method is a constant-time replacement for the following loop:

 Iterator<MutableEntry> eItr = index.iterator();
 int curPosition = 0;
 while (eItr.hasNext() && curPosition++ < nthPosition)
        eItr.next();
 ObjectId result = eItr.next().toObjectId();
 

Specified by:

getObjectId in class PackIndex

Parameters:

nthPosition - position within the traversal of PackIndex.iterator() that the caller needs the object for. The first returned PackIndex.MutableEntry is 0, the second is 1, etc.

Returns:

the ObjectId for the corresponding entry.

getOffset

public long getOffset(long nthPosition)

Get offset in a pack for the n-th object entry returned by PackIndex.iterator().

Specified by:

getOffset in class PackIndex

Parameters:

nthPosition - unsigned 32 bit position within the traversal of PackIndex.iterator() for which the caller needs the offset. The first returned PackIndex.MutableEntry is 0, the second is 1, etc. Positions past 2**31-1 are negative, but still valid.

Returns:

the offset in a pack for the corresponding entry.

findOffset

public long findOffset(AnyObjectId objId)

Locate the file offset position for the requested object.

Specified by:

findOffset in class PackIndex

Parameters:

objId - name of the object to locate within the pack.

Returns:

offset of the object's header and compressed content; -1 if the object does not exist in this index and is thus not stored in the associated pack.

getOffset

private long getOffset(int levelOne,
                       int levelTwo)

findCRC32

public long findCRC32(AnyObjectId objId)
               throws MissingObjectException

Retrieve stored CRC32 checksum of the requested object raw-data (including header).

Specified by:

findCRC32 in class PackIndex

Parameters:

objId - id of object to look for

Returns:

CRC32 checksum of specified object (at 32 less significant bits)

Throws:

MissingObjectException - when requested ObjectId was not found in this index

hasCRC32Support

public boolean hasCRC32Support()

Check whether this index supports (has) CRC32 checksums for objects.

Specified by:

hasCRC32Support in class PackIndex

Returns:

true if CRC32 is stored, false otherwise

iterator

public java.util.Iterator<PackIndex.MutableEntry> iterator()

Provide iterator that gives access to index entries. Note, that iterator returns reference to mutable object, the same reference in each call - for performance reason. If client needs immutable objects, it must copy returned object on its own.

Iterator returns objects in SHA-1 lexicographical order.

Specified by:

iterator in interface java.lang.Iterable<PackIndex.MutableEntry>

Specified by:

iterator in class PackIndex

resolve

public void resolve(java.util.Set<ObjectId> matches,
                    AbbreviatedObjectId id,
                    int matchLimit)
             throws java.io.IOException

Find objects matching the prefix abbreviation.

Specified by:

resolve in class PackIndex

Parameters:

matches - set to add any located ObjectIds to. This is an output parameter.

id - prefix to search for.

matchLimit - maximum number of results to return. At most this many ObjectIds should be added to matches before returning.

Throws:

java.io.IOException - the index cannot be read.

idOffset

private static int idOffset(int p)

binarySearchLevelTwo

private int binarySearchLevelTwo(AnyObjectId objId,
                                 int levelOne)