org.eclipse.jgit.internal.storage.file

Class GC

java.lang.Object

org.eclipse.jgit.internal.storage.file.GC

public class GC
extends Object

A garbage collector for git FileRepository. Instances of this class are not thread-safe. Don't use the same instance from multiple threads. This class started as a copy of DfsGarbageCollector from Shawn O. Pearce adapted to FileRepositories.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GC.RepoStatistics A class holding statistical data for a FileRepository regarding how many objects are stored as loose or packed objects

Constructor Summary

Constructors

Constructor and Description
GC(FileRepository repo) Creates a new garbage collector with default values.

Method Summary

Modifier and Type	Method and Description
Collection<PackFile>	gc() Runs a garbage collector on a FileRepository.
GC.RepoStatistics	getStatistics() Returns information about objects and pack files for a FileRepository.
void	packRefs() Packs all non-symbolic, loose refs into packed-refs.
void	prune(Set<ObjectId> objectsToKeep) Like "git prune" this method tries to prune all loose objects which are unreferenced.
void	prunePacked() Like "git prune-packed" this method tries to prune all loose objects which can be found in packs.
Collection<PackFile>	repack() Packs all objects which reachable from any of the heads into one pack file.
void	setAuto(boolean auto) Set the gc --auto option.
static void	setExecutor(ExecutorService e) Set the executor for running auto-gc in the background.
void	setExpire(Date expire) During gc() or prune() each unreferenced, loose object which has been created or modified after or at expire will not be pruned.
void	setExpireAgeMillis(long expireAgeMillis) During gc() or prune() each unreferenced, loose object which has been created or modified in the last expireAgeMillis milliseconds will not be pruned.
void	setPackConfig(PackConfig pconfig) Set the PackConfig used when (re-)writing packfiles.
void	setPackExpire(Date packExpire) During gc() or prune() packfiles which are created or modified after or at packExpire will not be deleted.
void	setPackExpireAgeMillis(long packExpireAgeMillis) During gc() or prune() packfiles which are created or modified in the last packExpireAgeMillis milliseconds will not be deleted.
GC	setProgressMonitor(ProgressMonitor pm) Set the progress monitor used for garbage collection methods.

Methods inherited from class java.lang.Object

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

Constructor Detail

GC

public GC(FileRepository repo)

Creates a new garbage collector with default values. An expirationTime of two weeks and null as progress monitor will be used.

Parameters:

repo - the repo to work on

Method Detail

setExecutor

public static void setExecutor(ExecutorService e)

Set the executor for running auto-gc in the background. If no executor is set JGit's own WorkQueue will be used.

Parameters:

e - the executor to be used for running auto-gc

gc

public Collection<PackFile> gc()
                        throws IOException,
                               ParseException

Runs a garbage collector on a FileRepository. It will

• pack loose references into packed-refs
• repack all reachable objects into new pack files and delete the old pack files
• prune all loose objects which are now reachable by packs

If setAuto(boolean) was set to true gc will first check whether any housekeeping is required; if not, it exits without performing any work. If setBackground(boolean) was set to true collectGarbage will start the gc in the background, and then return immediately. In this case, errors will not be reported except in gc.log.

Returns:

the collection of PackFile's which are newly created

Throws:

IOException

ParseException - If the configuration parameter "gc.pruneexpire" couldn't be parsed

prunePacked

public void prunePacked()
                 throws IOException

Like "git prune-packed" this method tries to prune all loose objects which can be found in packs. If certain objects can't be pruned (e.g. because the filesystem delete operation fails) this is silently ignored.

Throws:

IOException

prune

public void prune(Set<ObjectId> objectsToKeep)
           throws IOException,
                  ParseException

Like "git prune" this method tries to prune all loose objects which are unreferenced. If certain objects can't be pruned (e.g. because the filesystem delete operation fails) this is silently ignored.

Parameters:

objectsToKeep - a set of objects which should explicitly not be pruned

Throws:

IOException

ParseException - If the configuration parameter "gc.pruneexpire" couldn't be parsed

packRefs

public void packRefs()
              throws IOException

Packs all non-symbolic, loose refs into packed-refs.

Throws:

IOException

repack

public Collection<PackFile> repack()
                            throws IOException

Packs all objects which reachable from any of the heads into one pack file. Additionally all objects which are not reachable from any head but which are reachable from any of the other refs (e.g. tags), special refs (e.g. FETCH_HEAD) or index are packed into a separate pack file. Objects included in pack files which have a .keep file associated are never repacked. All old pack files which existed before are deleted.

Returns:

a collection of the newly created pack files

Throws:

IOException - when during reading of refs, index, packfiles, objects, reflog-entries or during writing to the packfiles IOException occurs

getStatistics

public GC.RepoStatistics getStatistics()
                                throws IOException

Returns information about objects and pack files for a FileRepository.

Returns:

information about objects and pack files for a FileRepository

Throws:

IOException

setProgressMonitor

public GC setProgressMonitor(ProgressMonitor pm)

Set the progress monitor used for garbage collection methods.

Parameters:

pm - a ProgressMonitor object.

Returns:

this

setExpireAgeMillis

public void setExpireAgeMillis(long expireAgeMillis)

During gc() or prune() each unreferenced, loose object which has been created or modified in the last expireAgeMillis milliseconds will not be pruned. Only older objects may be pruned. If set to 0 then every object is a candidate for pruning.

Parameters:

expireAgeMillis - minimal age of objects to be pruned in milliseconds.

setPackExpireAgeMillis

public void setPackExpireAgeMillis(long packExpireAgeMillis)

During gc() or prune() packfiles which are created or modified in the last packExpireAgeMillis milliseconds will not be deleted. Only older packfiles may be deleted. If set to 0 then every packfile is a candidate for deletion.

Parameters:

packExpireAgeMillis - minimal age of packfiles to be deleted in milliseconds.

setPackConfig

public void setPackConfig(@NonNull
                          PackConfig pconfig)

Set the PackConfig used when (re-)writing packfiles. This allows to influence how packs are written and to implement something similar to "git gc --aggressive"

Parameters:

pconfig - the PackConfig used when writing packs

setExpire

public void setExpire(Date expire)

During gc() or prune() each unreferenced, loose object which has been created or modified after or at expire will not be pruned. Only older objects may be pruned. If set to null then every object is a candidate for pruning.

Parameters:

expire - instant in time which defines object expiration objects with modification time before this instant are expired objects with modification time newer or equal to this instant are not expired

setPackExpire

public void setPackExpire(Date packExpire)

During gc() or prune() packfiles which are created or modified after or at packExpire will not be deleted. Only older packfiles may be deleted. If set to null then every packfile is a candidate for deletion.

Parameters:

packExpire - instant in time which defines packfile expiration

setAuto

public void setAuto(boolean auto)

Set the gc --auto option. With this option, gc checks whether any housekeeping is required; if not, it exits without performing any work. Some JGit commands run gc --auto after performing operations that could create many loose objects.

Housekeeping is required if there are too many loose objects or too many packs in the repository. If the number of loose objects exceeds the value of the gc.auto option JGit GC consolidates all existing packs into a single pack (equivalent to -A option), whereas git-core would combine all loose objects into a single pack using repack -d -l. Setting the value of gc.auto to 0 disables automatic packing of loose objects.

If the number of packs exceeds the value of gc.autoPackLimit, then existing packs (except those marked with a .keep file) are consolidated into a single pack by using the -A option of repack. Setting gc.autoPackLimit to 0 disables automatic consolidation of packs.

Like git the following jgit commands run auto gc:

• fetch
• merge
• rebase
• receive-pack

The auto gc for receive-pack can be suppressed by setting the config option receive.autogc = false

Parameters:

auto - defines whether gc should do automatic housekeeping