Class DfsRefDatabase

    • 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()
        Get the repository the database holds the references of.
        Returns:
        the repository the database holds the references of.
      • getRefs

        public Map<String,​Ref> getRefs​(String prefix)
                                      throws IOException
        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
        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
        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
        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
        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()
        Initialize a new reference database at this location.
        Specified by:
        create in class RefDatabase
      • refresh

        public void refresh()
        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()
        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.

        Two reference match if and only if they satisfy the following:

        • If one reference is a symbolic ref, the other one should be a symbolic ref.
        • If both are symbolic refs, the target names should be same.
        • If both are object ID refs, the object IDs should be same.
        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.