(*
Module: Nsswitch
  Parses /etc/nsswitch.conf

Author: Raphael Pinson <raphink@gmail.com>

About: Reference
  This lens tries to keep as close as possible to `man nsswitch.conf` where possible.

About: Licence
  This file is licensed under the LGPLv2+, like the rest of Augeas.

About: Lens Usage

About: Configuration files
  This lens applies to /etc/nsswitch.conf. See <filter>.
*)

module Nsswitch =
autoload xfm

(************************************************************************
 * Group:                 USEFUL PRIMITIVES
 *************************************************************************)

(* View: comment *)
let comment = Util.comment

(* View: empty *)
let empty = Util.empty

(* View: sep_colon
    The separator for database entries *)
let sep_colon = del /:[ \t]*/ ": "

(* View: service
    The service specification like `files', `db', or `nis' *)
let service = [ label "service" . store Rx.word ]

(* View: reaction
    The reaction on lookup result like `[NOTFOUND=return]' *)
let reaction =
  let status_kw = /success/i
                | /notfound/i
                | /unavail/i
                | /tryagain/i
    in let action_kw = /return/i
                     | /continue/i
      in let negate = [ Util.del_str "!" . label "negate" ]
        in let reaction_entry = [ label "status" . negate?
                                . store status_kw
                                . Util.del_str "="
                                . [ label "action" . store action_kw ] ]
          in Util.del_str "["
             . [ label "reaction"
               . (Build.opt_list reaction_entry Sep.space) ]
             . Util.del_str "]"

(* View: database *)
let database =
  let database_kw = "aliases"
                  | "ethers"
                  | "group"
                  | "hosts"
                  | "netgroup"
                  | "networks"
                  | "passwd"
                  | "protocols"
                  | "publickey"
                  | "rpc"
                  | "services"
                  | "shadow"
    in [ label "database" . store database_kw
               . sep_colon
               . (Build.opt_list
                    (service|reaction)
                    Sep.space)
               . Util.eol ]

(* View: lns *)
let lns = ( empty | comment | database )*

(* Variable: filter *)
let filter = (incl "/etc/resolv.conf")
    . Util.stdexcl

let xfm = transform lns filter