Class PackIndex
- All Implemented Interfaces:
Iterable<PackIndex.MutableEntry>
,ObjectIdSet
- Direct Known Subclasses:
PackIndexV1
,PackIndexV2
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Nested Class Summary
Nested ClassesModifier and TypeClassDescription(package private) class
static class
Represent mutable entry of pack index consisting of object id and offset in pack (both mutable). -
Field Summary
FieldsModifier and TypeFieldDescriptionprotected byte[]
Footer checksum applied on the bottom of the pack file. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionboolean
contains
(AnyObjectId id) Returns true if the objectId is contained within the collection.abstract long
findCRC32
(AnyObjectId objId) Retrieve stored CRC32 checksum of the requested object raw-data (including header).abstract long
findOffset
(AnyObjectId objId) Locate the file offset position for the requested object.byte[]
abstract long
Obtain the total number of objects described by this index.final ObjectId
getObjectId
(int nthPosition) Get ObjectId for the n-th object entry returned byiterator()
.abstract ObjectId
getObjectId
(long nthPosition) Get ObjectId for the n-th object entry returned byiterator()
.(package private) abstract long
getOffset
(long nthPosition) Get offset in a pack for the n-th object entry returned byiterator()
.abstract long
Obtain the total number of objects needing 64 bit offsets.abstract boolean
Check whether this index supports (has) CRC32 checksums for objects.boolean
hasObject
(AnyObjectId id) Determine if an object is contained within the pack file.private static boolean
isTOC
(byte[] h) abstract Iterator<PackIndex.MutableEntry>
iterator()
static PackIndex
Open an existing pack.idx
file for reading.static PackIndex
read
(InputStream fd) Read an existing pack index file from a buffered stream.abstract void
resolve
(Set<ObjectId> matches, AbbreviatedObjectId id, int matchLimit) Find objects matching the prefix abbreviation.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
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Field Details
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packChecksum
protected byte[] packChecksumFooter checksum applied on the bottom of the pack file.
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Constructor Details
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PackIndex
public PackIndex()
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Method Details
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open
Open an existing pack.idx
file for reading.The format of the file will be automatically detected and a proper access implementation for that format will be constructed and returned to the caller. The file may or may not be held open by the returned instance.
- Parameters:
idxFile
- existing pack .idx to read.- Returns:
- access implementation for the requested file.
- Throws:
FileNotFoundException
- the file does not exist.IOException
- the file exists but could not be read due to security errors, unrecognized data version, or unexpected data corruption.
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read
Read an existing pack index file from a buffered stream.The format of the file will be automatically detected and a proper access implementation for that format will be constructed and returned to the caller. The file may or may not be held open by the returned instance.
- Parameters:
fd
- stream to read the index file from. The stream must be buffered as some small IOs are performed against the stream. The caller is responsible for closing the stream.- Returns:
- a copy of the index in-memory.
- Throws:
IOException
- the stream cannot be read.CorruptObjectException
- the stream does not contain a valid pack index.
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isTOC
private static boolean isTOC(byte[] h) -
hasObject
Determine if an object is contained within the pack file.- Parameters:
id
- the object to look for. Must not be null.- Returns:
- true if the object is listed in this index; false otherwise.
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contains
Returns true if the objectId is contained within the collection.- Specified by:
contains
in interfaceObjectIdSet
- Parameters:
id
- the objectId to find- Returns:
- whether the collection contains the objectId.
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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 interfaceIterable<PackIndex.MutableEntry>
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getObjectCount
public abstract long getObjectCount()Obtain the total number of objects described by this index.- Returns:
- number of objects in this index, and likewise in the associated pack that this index was generated from.
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getOffset64Count
public abstract long getOffset64Count()Obtain the total number of objects needing 64 bit offsets.- 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.
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getObjectId
Get ObjectId for the n-th object entry returned byiterator()
.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();
- Parameters:
nthPosition
- position within the traversal ofiterator()
that the caller needs the object for. The first returnedPackIndex.MutableEntry
is 0, the second is 1, etc.- Returns:
- the ObjectId for the corresponding entry.
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getObjectId
Get ObjectId for the n-th object entry returned byiterator()
.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();
- Parameters:
nthPosition
- unsigned 32 bit position within the traversal ofiterator()
that the caller needs the object for. The first returnedPackIndex.MutableEntry
is 0, the second is 1, etc. Positions past 2**31-1 are negative, but still valid.- Returns:
- the ObjectId for the corresponding entry.
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getOffset
abstract long getOffset(long nthPosition) Get offset in a pack for the n-th object entry returned byiterator()
.- Parameters:
nthPosition
- unsigned 32 bit position within the traversal ofiterator()
for which the caller needs the offset. The first returnedPackIndex.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.
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findOffset
Locate the file offset position for the requested object.- 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.
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findCRC32
public abstract long findCRC32(AnyObjectId objId) throws MissingObjectException, UnsupportedOperationException Retrieve stored CRC32 checksum of the requested object raw-data (including header).- 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 indexUnsupportedOperationException
- when this index doesn't support CRC32 checksum
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hasCRC32Support
public abstract boolean hasCRC32Support()Check whether this index supports (has) CRC32 checksums for objects.- Returns:
- true if CRC32 is stored, false otherwise
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resolve
public abstract void resolve(Set<ObjectId> matches, AbbreviatedObjectId id, int matchLimit) throws IOException Find objects matching the prefix abbreviation.- 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:
IOException
- the index cannot be read.
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getChecksum
public byte[] getChecksum()- Returns:
- the checksum of the pack; caller must not modify it
- Since:
- 5.5
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