org.eclipse.jgit.storage.dfs
Class DfsRefDatabase

java.lang.Object
  extended by org.eclipse.jgit.lib.RefDatabase
      extended by org.eclipse.jgit.storage.dfs.DfsRefDatabase

public abstract class DfsRefDatabase
extends RefDatabase


Nested Class Summary
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
protected DfsRefDatabase(DfsRepository repository)
          Initialize the reference database for a repository.
 
Method Summary
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.
 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.
 org.eclipse.jgit.storage.dfs.DfsRefUpdate 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.
protected abstract  DfsRefDatabase.RefCache scanAllRefs()
          Read all known references in the repository.
 
Methods inherited from class org.eclipse.jgit.lib.RefDatabase
refresh
 
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.

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.

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)

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 org.eclipse.jgit.storage.dfs.DfsRefUpdate 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.

create

public void create()
Description copied from class: RefDatabase
Initialize a new reference database at this location.

Specified by:
create 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.


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