module type BACKEND =sig..end
val pull_url : OpamTypes.package ->
       OpamTypes.dirname ->
       string option ->
       OpamTypes.address ->
       OpamTypes.generic_file OpamTypes.download OpamProcess.job
val pull_repo : OpamTypes.repository -> unit OpamProcess.job
val pull_archive : OpamTypes.repository ->
       OpamTypes.filename -> OpamTypes.filename OpamTypes.download OpamProcess.job
val revision : OpamTypes.repository -> OpamTypes.version option OpamProcess.job