Queries the refdb backend to determine if the given ref_name exists. A refdb implementation must provide this function.

Queries the refdb backend for a given reference. A refdb implementation must provide this function.

Allocate an iterator object for the backend.

A refdb implementation must provide this function.

Deletes the given reference from the refdb. A refdb implementation must provide this function.

Suggests that the given refdb compress or optimize its references. This mechanism is implementation specific. (For on-disk reference databases, this may pack all loose references.) A refdb implementation may provide this function; if it is not provided, nothing will be done.

Query whether a particular reference has a log (may be empty)

Make sure a particular reference will have a reflog which will be appended to on writes.

Frees any resources held by the refdb. A refdb implementation may provide this function; if it is not provided, nothing will be done.

Read the reflog for the given reference name.

Write a reflog to disk.

Rename a reflog

Remove a reflog.

Lock a reference. The opaque parameter will be passed to the unlock function

Unlock a reference. Only one of target or symbolic_target will be set. success indicates whether to update the reference or discard the lock (if it's false)