org.eclipse.jgit.storage.pack
Class CachedPack

java.lang.Object
  org.eclipse.jgit.storage.pack.CachedPack

Direct Known Subclasses:

DfsCachedPack

public abstract class CachedPack
extends Object

Describes a pack file ObjectReuseAsIs can append onto a stream.

Constructor Summary

CachedPack()

Method Summary

long	getDeltaCount() Get the number of delta objects stored in this pack.
abstract long	getObjectCount() Get the number of objects in this pack.
abstract Set<ObjectId>	getTips() Objects that start this pack.
abstract boolean	hasObject(ObjectToPack obj, StoredObjectRepresentation rep) Determine if this pack contains the object representation given.

Methods inherited from class java.lang.Object

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

Constructor Detail

CachedPack

public CachedPack()

Method Detail

getTips

public abstract Set<ObjectId> getTips()

Objects that start this pack.

All objects reachable from the tips are contained within this pack. If PackWriter is going to include everything reachable from all of these objects, this cached pack is eligible to be appended directly onto the output pack stream.

Returns:

the tip objects that describe this pack.

getObjectCount

public abstract long getObjectCount()
                             throws IOException

Get the number of objects in this pack.

Returns:

the total object count for the pack.

Throws:

IOException - if the object count cannot be read.

getDeltaCount

public long getDeltaCount()
                   throws IOException

Get the number of delta objects stored in this pack.

This is an optional method, not every cached pack storage system knows the precise number of deltas stored within the pack. This number must be smaller than getObjectCount() as deltas are not supposed to span across pack files.

This method must be fast, if the only way to determine delta counts is to scan the pack file's contents one object at a time, implementors should return 0 and avoid the high cost of the scan.

Returns:

the number of deltas; 0 if the number is not known or there are no deltas.

Throws:

IOException - if the delta count cannot be read.

hasObject

public abstract boolean hasObject(ObjectToPack obj,
                                  StoredObjectRepresentation rep)

Determine if this pack contains the object representation given.

PackWriter uses this method during the finding sources phase to prune away any objects from the leading thin-pack that already appear within this pack and should not be sent twice.

Implementors are strongly encouraged to rely on looking at rep only and using its internal state to decide if this object is within this pack. Implementors should ensure a representation from this cached pack is tested as part of ObjectReuseAsIs.selectObjectRepresentation(PackWriter, org.eclipse.jgit.lib.ProgressMonitor, Iterable) , ensuring this method would eventually return true if the object would be included by this cached pack.

Parameters:

obj - the object being packed. Can be used as an ObjectId.

rep - representation from the ObjectReuseAsIs instance that originally supplied this CachedPack.

Returns:

true if this pack contains this object.