refactor: formatting helpers

* inline most heplers as they are only used once.
* give more precise types to the function that does the action

Signed-off-by: Rudi Grinberg <[email protected]>

bin/dune_init.ml

@@ -137,7 +137,7 @@ module File = struct
     let content =
       if not (Path.exists full_path) then []
       else
-        match Dune_lang.Format.parse_file (Some full_path) with
+        match Io.with_lexbuf_from_file ~f:Dune_lang.Format.parse full_path with
         | Dune_lang.Format.Sexps content -> content
         | Dune_lang.Format.OCaml_syntax _ ->
           User_error.raise
@@ -152,7 +152,12 @@ module File = struct
     let version =
       Dune_lang.Syntax.greatest_supported_version Dune_engine.Stanza.syntax
     in
-    Dune_lang.Format.write_file ~version ~path dune_file.content
+    Io.with_file_out ~binary:true
+      (* Why do we pass [~binary:true] but not anywhere else when formatting? *)
+      path ~f:(fun oc ->
+        let fmt = Format.formatter_of_out_channel oc in
+        Format.fprintf fmt "%a%!" Pp.to_fmt
+          (Dune_lang.Format.pp_top_sexps ~version dune_file.content))
 
   let write f =
     let path = full_path f in

bin/format_dune_file.ml

@@ -14,6 +14,26 @@ let man =
 
 let info = Term.info "format-dune-file" ~doc ~man
 
+let format_file ~version ~input =
+  let with_input =
+    match input with
+    | Some path -> fun f -> Io.with_lexbuf_from_file path ~f
+    | None ->
+      fun f ->
+        Exn.protect
+          ~f:(fun () -> f (Lexing.from_channel stdin))
+          ~finally:(fun () -> close_in_noerr stdin)
+  in
+  match with_input Dune_lang.Format.parse with
+  | Sexps sexps ->
+    Format.fprintf Format.std_formatter "%a%!" Pp.to_fmt
+      (Dune_lang.Format.pp_top_sexps ~version sexps)
+  | OCaml_syntax loc -> (
+    match input with
+    | None -> User_error.raise ~loc [ Pp.text "OCaml syntax is not supported." ]
+    | Some path ->
+      Io.with_file_in path ~f:(fun ic -> Io.copy_channels ic stdout))
+
 let term =
   let+ path_opt =
     let docv = "FILE" in
@@ -28,6 +48,6 @@ let term =
     Arg.(value & opt version default & info [ "dune-version" ] ~docv ~doc)
   in
   let input = Option.map ~f:Arg.Path.path path_opt in
-  Dune_lang.Format.format_file ~version ~input ~output:None
+  format_file ~version ~input
 
 let command = (term, info)

src/dune_engine/action_exec.ml

@@ -367,8 +367,7 @@ let rec exec t ~ectx ~eenv =
   | No_infer t -> exec t ~ectx ~eenv
   | Pipe (outputs, l) -> exec_pipe ~ectx ~eenv outputs l
   | Format_dune_file (version, src, dst) ->
-    Dune_lang.Format.format_file ~version ~input:(Some src)
-      ~output:(Some (Path.build dst));
+    Dune_lang.Format.format_action ~version ~src ~dst;
     Fiber.return Done
   | Cram script ->
     let+ () =

src/dune_lang/format.ml

@@ -6,15 +6,10 @@ type dune_file =
   | OCaml_syntax of Loc.t
   | Sexps of Cst.t list
 
-let parse_lexbuf lb =
+let parse lb =
   if Dune_lexer.is_script lb then OCaml_syntax (Loc.of_lexbuf lb)
   else Sexps (Parser.parse lb ~mode:Cst)
 
-let parse_file path_opt =
-  match path_opt with
-  | Some path -> Io.with_lexbuf_from_file path ~f:parse_lexbuf
-  | None -> parse_lexbuf @@ Lexing.from_channel stdin
-
 let can_be_displayed_wrapped =
   List.for_all ~f:(fun (c : Cst.t) ->
       match c with
@@ -66,35 +61,18 @@ let pp_top_sexp ~version sexp = pp_sexp ~version sexp ++ Pp.char '\n'
 let pp_top_sexps ~version =
   Pp.concat_map ~sep:Pp.newline ~f:(pp_top_sexp ~version)
 
-let write_file ~version ~path sexps =
-  let f oc =
-    let fmt = Format.formatter_of_out_channel oc in
-    Format.fprintf fmt "%a%!" Pp.to_fmt (pp_top_sexps ~version sexps)
-  in
-  Io.with_file_out ~binary:true path ~f
-
 let format_string ~version input =
-  match parse_lexbuf (Lexing.from_string input) with
+  match parse (Lexing.from_string input) with
   | OCaml_syntax _ ->
     User_error.raise [ Pp.text "OCaml syntax is not supported." ]
   | Sexps sexps ->
     Format.asprintf "%a%!" Pp.to_fmt (pp_top_sexps ~version sexps)
 
-let format_file ~version ~input ~output =
-  let with_output f =
-    match output with
-    | None -> f stdout
-    | Some output -> Io.with_file_out output ~f
-  in
-  match parse_file input with
-  | OCaml_syntax loc -> (
-    match input with
-    | Some path ->
-      Io.with_file_in path ~f:(fun ic ->
-          with_output (fun oc -> Io.copy_channels ic oc))
-    | None -> User_error.raise ~loc [ Pp.text "OCaml syntax is not supported." ]
-    )
+let format_action ~version ~src ~dst =
+  let dst = Path.build dst in
+  match Io.with_lexbuf_from_file src ~f:parse with
+  | OCaml_syntax _ -> Io.copy_file ~src ~dst ()
   | Sexps sexps ->
-    with_output (fun oc ->
+    Io.with_file_out dst ~f:(fun oc ->
         let oc = Format.formatter_of_out_channel oc in
         Format.fprintf oc "%a%!" Pp.to_fmt (pp_top_sexps ~version sexps))

src/dune_lang/format.mli

@@ -6,19 +6,11 @@ type dune_file =
 
 val format_string : version:Syntax.Version.t -> string -> string
 
-(** Read a file into its concrete syntax *)
-val parse_file : Path.t option -> dune_file
+val parse : Lexing.lexbuf -> dune_file
 
-(** Write the formatted concrete syntax to the file at [path] *)
-val write_file : version:Syntax.Version.t -> path:Path.t -> Cst.t list -> unit
-
-(** Reformat a dune file. [None] in [input] corresponds to stdin. [None] in
-    [output] corresponds to stdout. *)
-val format_file :
-     version:Syntax.Version.t
-  -> input:Path.t option
-  -> output:Path.t option
-  -> unit
+(** Reformat a dune file in a dune action *)
+val format_action :
+  version:Syntax.Version.t -> src:Path.t -> dst:Path.Build.t -> unit
 
 (** Pretty-print a list of toplevel s-expressions *)
 val pp_top_sexps : version:Syntax.Version.t -> Cst.t list -> _ Pp.t