org.eclipse.jgit.internal.storage.dfs

Class DfsRefDatabase

java.lang.Object

org.eclipse.jgit.lib.RefDatabase

org.eclipse.jgit.internal.storage.dfs.DfsRefDatabase

public abstract class DfsRefDatabase
extends RefDatabase

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DfsRefDatabase.RefCache Collection of references managed by this database.

Field Summary

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

ALL, MAX_SYMBOLIC_REF_DEPTH, SEARCH_PATH

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DfsRefDatabase(DfsRepository repository) Initialize the reference database for a repository.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	cachePeeledState(Ref oldLeaf, Ref newLeaf) Update the cached peeled state of a reference
void	close() Close any resources held by this database.
protected abstract boolean	compareAndPut(Ref oldRef, Ref newRef) Compare a reference, and put if it matches.
protected abstract boolean	compareAndRemove(Ref oldRef) Compare a reference, and delete if it matches.
void	create() Initialize a new reference database at this location.
Ref	exactRef(String name) Read a single reference.
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.
protected DfsRepository	getRepository()
boolean	isNameConflicting(String refName) Determine if a proposed reference name overlaps with an existing one.
RefRename	newRename(String fromName, String toName) Create a new update command to rename a reference.
RefUpdate	newUpdate(String refName, boolean detach) Create a new update command to create, modify or delete a reference.
Ref	peel(Ref ref) Peel a possibly unpeeled reference by traversing the annotated tags.
void	refresh() Triggers a refresh of all internal data structures.
protected abstract DfsRefDatabase.RefCache	scanAllRefs() Read all known references in the repository.

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

exactRef, findRef, firstExactRef, getConflictingNames, newBatchUpdate, performsAtomicTransactions

Methods inherited from class java.lang.Object

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

Constructor Detail

DfsRefDatabase

protected DfsRefDatabase(DfsRepository repository)

Initialize the reference database for a repository.

Parameters:

repository - the repository this database instance manages references for.

Method Detail

getRepository

protected DfsRepository getRepository()

Returns:

the repository the database holds the references of.

exactRef

public Ref exactRef(String name)
             throws IOException

Description copied from class: RefDatabase

Read a single reference.

Unlike RefDatabase.getRef(java.lang.String), this method expects an unshortened reference name and does not search using the standard RefDatabase.SEARCH_PATH.

Overrides:

exactRef in class RefDatabase

Parameters:

name - the unabbreviated name of the reference.

Returns:

the reference (if it exists); else null.

Throws:

IOException - the reference space cannot be accessed.

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).

To read a specific reference without using @{link #SEARCH_PATH}, see RefDatabase.exactRef(String).

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.

getAdditionalRefs

public List<Ref> getAdditionalRefs()

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) and RefDatabase.exactRef(String).

Specified by:

getAdditionalRefs in class RefDatabase

Returns:

a list of additional refs

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.

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 RefUpdate newUpdate(String refName,
                  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:

refName - 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 RefRename 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.

isNameConflicting

public boolean isNameConflicting(String refName)
                          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:

refName - 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)

create

public void create()

Description copied from class: RefDatabase

Initialize a new reference database at this location.

Specified by:

create 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

close

public void close()

Description copied from class: RefDatabase

Close any resources held by this database.

Specified by:

close in class RefDatabase

scanAllRefs

protected abstract DfsRefDatabase.RefCache scanAllRefs()
                                                throws IOException

Read all known references in the repository.

Returns:

all current references of the repository.

Throws:

IOException - references cannot be accessed.

compareAndPut

protected abstract boolean compareAndPut(Ref oldRef,
                    Ref newRef)
                                  throws IOException

Compare a reference, and put if it matches.

Parameters:

oldRef - old value to compare to. If the reference is expected to not exist the old value has a storage of Ref.Storage.NEW and an ObjectId value of null.

newRef - new reference to store.

Returns:

true if the put was successful; false otherwise.

Throws:

IOException - the reference cannot be put due to a system error.

compareAndRemove

protected abstract boolean compareAndRemove(Ref oldRef)
                                     throws IOException

Compare a reference, and delete if it matches.

Parameters:

oldRef - the old reference information that was previously read.

Returns:

true if the remove was successful; false otherwise.

Throws:

IOException - the reference could not be removed due to a system error.

cachePeeledState

protected void cachePeeledState(Ref oldLeaf,
                    Ref newLeaf)

Update the cached peeled state of a reference

The ref database invokes this method after it peels a reference that had not been peeled before. This allows the storage to cache the peel state of the reference, and if it is actually peelable, the target that it peels to, so that on-the-fly peeling doesn't have to happen on the next reference read.

Parameters:

oldLeaf - the old reference.

newLeaf - the new reference, with peel information.