org.eclipse.jgit.internal.storage.file

Class RefDirectory

java.lang.Object

org.eclipse.jgit.lib.RefDatabase

org.eclipse.jgit.internal.storage.file.RefDirectory

public class RefDirectory
extends RefDatabase

Traditional file system based RefDatabase.

This is the classical reference database representation for a Git repository. References are stored in two formats: loose, and packed.

Loose references are stored as individual files within the refs/ directory. The file name matches the reference name and the file contents is the current ObjectId in string form.

Packed references are stored in a single text file named packed-refs. In the packed format, each reference is stored on its own line. This file reduces the number of files needed for large reference spaces, reducing the overall size of a Git repository on disk.

Field Summary

Fields

Modifier and Type	Field and Description
static String	PACKED_REFS_HEADER Magic string denoting the header of a packed-refs file.
static String	PACKED_REFS_PEELED If in the header, denotes the file has peeled data.
static String	SYMREF Magic string denoting the start of a symbolic reference file.

Fields inherited from class org.eclipse.jgit.lib.RefDatabase

ALL, MAX_SYMBOLIC_REF_DEPTH, SEARCH_PATH

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close any resources held by this database.
void	create() Initialize a new reference database at this location.
List<Ref>	getAdditionalRefs() Get the additional reference-like entities from the repository.
Ref	getRef(String needle) Read a single reference.
Map<String,Ref>	getRefs(String prefix) Get a section of the reference namespace.
boolean	isNameConflicting(String name) Determine if a proposed reference name overlaps with an existing one.
org.eclipse.jgit.internal.storage.file.RefDirectoryRename	newRename(String fromName, String toName) Create a new update command to rename a reference.
org.eclipse.jgit.internal.storage.file.RefDirectoryUpdate	newUpdate(String name, boolean detach) Create a new update command to create, modify or delete a reference.
void	pack(List<String> refs) Adds a set of refs to the set of packed-refs.
Ref	peel(Ref ref) Peel a possibly unpeeled reference by traversing the annotated tags.
void	refresh() Triggers a refresh of all internal data structures.

Methods inherited from class org.eclipse.jgit.lib.RefDatabase

findRef, getConflictingNames, newBatchUpdate, performsAtomicTransactions

Methods inherited from class java.lang.Object

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

Field Detail

SYMREF

public static final String SYMREF

Magic string denoting the start of a symbolic reference file.

See Also:

Constant Field Values

PACKED_REFS_HEADER

public static final String PACKED_REFS_HEADER

Magic string denoting the header of a packed-refs file.

See Also:

Constant Field Values

PACKED_REFS_PEELED

public static final String PACKED_REFS_PEELED

If in the header, denotes the file has peeled data.

See Also:

Constant Field Values

Method Detail

create

public void create()
            throws IOException

Description copied from class: RefDatabase

Initialize a new reference database at this location.

Specified by:

create in class RefDatabase

Throws:

IOException - the database could not be created.

close

public void close()

Description copied from class: RefDatabase

Close any resources held by this database.

Specified by:

close in class RefDatabase

refresh

public void refresh()

Description copied from class: RefDatabase

Triggers a refresh of all internal data structures.

In case the RefDatabase implementation has internal caches this method will trigger that all these caches are cleared.

Implementors should overwrite this method if they use any kind of caches.

Overrides:

refresh in class RefDatabase

isNameConflicting

public boolean isNameConflicting(String name)
                          throws IOException

Description copied from class: RefDatabase

Determine if a proposed reference name overlaps with an existing one.

Reference names use '/' as a component separator, and may be stored in a hierarchical storage such as a directory on the local filesystem.

If the reference "refs/heads/foo" exists then "refs/heads/foo/bar" must not exist, as a reference cannot have a value and also be a container for other references at the same time.

If the reference "refs/heads/foo/bar" exists than the reference "refs/heads/foo" cannot exist, for the same reason.

Specified by:

isNameConflicting in class RefDatabase

Parameters:

name - proposed name.

Returns:

true if the name overlaps with an existing reference; false if using this name right now would be safe.

Throws:

IOException - the database could not be read to check for conflicts.

See Also:

RefDatabase.getConflictingNames(String)

getRef

public Ref getRef(String needle)
           throws IOException

Description copied from class: RefDatabase

Read a single reference.

Aside from taking advantage of RefDatabase.SEARCH_PATH, this method may be able to more quickly resolve a single reference name than obtaining the complete namespace by getRefs(ALL).get(name).

Specified by:

getRef in class RefDatabase

Parameters:

needle - the name of the reference. May be a short name which must be searched for using the standard RefDatabase.SEARCH_PATH.

Returns:

the reference (if it exists); else null.

Throws:

IOException - the reference space cannot be accessed.

getRefs

public Map<String,Ref> getRefs(String prefix)
                        throws IOException

Description copied from class: RefDatabase

Get a section of the reference namespace.

Specified by:

getRefs in class RefDatabase

Parameters:

prefix - prefix to search the namespace with; must end with /. If the empty string (RefDatabase.ALL), obtain a complete snapshot of all references.

Returns:

modifiable map that is a complete snapshot of the current reference namespace, with prefix removed from the start of each key. The map can be an unsorted map.

Throws:

IOException - the reference space cannot be accessed.

getAdditionalRefs

public List<Ref> getAdditionalRefs()
                            throws IOException

Description copied from class: RefDatabase

Get the additional reference-like entities from the repository.

The result list includes non-ref items such as MERGE_HEAD and FETCH_RESULT cast to be refs. The names of these refs are not returned by getRefs(ALL) but are accepted by RefDatabase.getRef(String)

Specified by:

getAdditionalRefs in class RefDatabase

Returns:

a list of additional refs

Throws:

IOException - the reference space cannot be accessed.

peel

public Ref peel(Ref ref)
         throws IOException

Description copied from class: RefDatabase

Peel a possibly unpeeled reference by traversing the annotated tags.

If the reference cannot be peeled (as it does not refer to an annotated tag) the peeled id stays null, but Ref.isPeeled() will be true.

Implementors should check Ref.isPeeled() before performing any additional work effort.

Specified by:

peel in class RefDatabase

Parameters:

ref - The reference to peel

Returns:

ref if ref.isPeeled() is true; otherwise a new Ref object representing the same data as Ref, but isPeeled() will be true and getPeeledObjectId() will contain the peeled object (or null).

Throws:

IOException - the reference space or object space cannot be accessed.

newUpdate

public org.eclipse.jgit.internal.storage.file.RefDirectoryUpdate newUpdate(String name,
                                                                  boolean detach)
                                                                    throws IOException

Description copied from class: RefDatabase

Create a new update command to create, modify or delete a reference.

Specified by:

newUpdate in class RefDatabase

Parameters:

name - the name of the reference.

detach - if true and name is currently a SymbolicRef, the update will replace it with an ObjectIdRef. Otherwise, the update will recursively traverse SymbolicRefs and operate on the leaf ObjectIdRef.

Returns:

a new update for the requested name; never null.

Throws:

IOException - the reference space cannot be accessed.

newRename

public org.eclipse.jgit.internal.storage.file.RefDirectoryRename newRename(String fromName,
                                                                  String toName)
                                                                    throws IOException

Description copied from class: RefDatabase

Create a new update command to rename a reference.

Specified by:

newRename in class RefDatabase

Parameters:

fromName - name of reference to rename from

toName - name of reference to rename to

Returns:

an update command that knows how to rename a branch to another.

Throws:

IOException - the reference space cannot be accessed.

pack

public void pack(List<String> refs)
          throws IOException

Adds a set of refs to the set of packed-refs. Only non-symbolic refs are added. If a ref with the given name already existed in packed-refs it is updated with the new value. Each loose ref which was added to the packed-ref file is deleted. If a given ref can't be locked it will not be added to the pack file.

Parameters:

refs - the refs to be added. Must be fully qualified.

Throws:

IOException