org.eclipse.jgit.storage.file
Class RefDirectory

java.lang.Object
  extended by org.eclipse.jgit.lib.RefDatabase
      extended by org.eclipse.jgit.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
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
 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.storage.file.RefDirectoryRename newRename(String fromName, String toName)
          Create a new update command to rename a reference.
 org.eclipse.jgit.storage.file.RefDirectoryUpdate newUpdate(String name, 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.
 
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.

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.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.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.


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