Add cxx extension for C++ stubs

CHANGES.md

@@ -5,6 +5,8 @@ unreleased
   fixes the support for `[@@deriving_inline]` with older versions of
   ppxlib (#...., @diml)
 
+- Add support for `.cxx` extension for C++ stubs (#1831, @rgrinberg)
+
 1.7.1 (13/02/2019)
 ------------------
 
@@ -16,6 +18,7 @@ unreleased
 1.7.0 (12/02/2019)
 ------------------
 
+
 - Second step of the deprecation of jbuilder: the `jbuilder` binary
   now emits a warning on every startup and both `jbuilder` and `dune`
   emit warnings when encountering `jbuild` files (#1752, @diml)

src/c.ml

@@ -10,16 +10,31 @@ module Kind = struct
     | C -> Format.pp_print_string fmt "c"
     | Cxx -> Format.pp_print_string fmt "cpp"
 
-  let split_extension fn =
-    match String.lsplit2 fn ~on:'.' with
-    | Some (obj, "c") -> Some (obj, C)
-    | Some (obj, "cpp") -> Some (obj, Cxx)
-    | _ -> None
+  type split =
+    | Unrecognized
+    | Not_allowed_until of Syntax.Version.t
+    | Recognized of string * t
 
-  let possible_fns t fn =
+  let split_extension fn ~dune_version =
+    match String.lsplit2 fn ~on:'.' with
+    | Some (obj, "c") -> Recognized (obj, C)
+    | Some (obj, "cpp") -> Recognized (obj, Cxx)
+    | Some (obj, "cxx") ->
+      if dune_version >= (1, 8) then
+        Recognized (obj, Cxx)
+      else
+        Not_allowed_until (1, 8)
+    | _ -> Unrecognized
+
+  let possible_fns t fn ~dune_version =
     match t with
     | C -> [fn ^ ".c"]
-    | Cxx -> [fn ^ ".cpp"]
+    | Cxx ->
+      let cxx = [fn ^ ".cpp"] in
+      if dune_version >= (1, 8) then
+        (fn ^ ".cxx") :: cxx
+      else
+        cxx
 
   module Dict = struct
     type 'a t =

src/c.mli

@@ -7,11 +7,19 @@ module Kind : sig
 
   val pp : t Fmt.t
 
-  val split_extension : string -> (string * t) option
+  type split =
+    | Unrecognized
+    | Not_allowed_until of Syntax.Version.t
+    | Recognized of string * t
+
+  val split_extension
+    :  string
+    -> dune_version:Syntax.Version.t
+    -> split
 
   (** [possible_fns t s] returns the possible filenames given the extension-less
       basenames [s] *)
-  val possible_fns : t -> string -> string list
+  val possible_fns : t -> string -> dune_version:Syntax.Version.t -> string list
 
   module Dict : sig
     type kind

src/c_sources.ml

@@ -45,12 +45,18 @@ module Eval = struct
   include Ordered_set_lang.Make_loc(String)(Value)
 end
 
-let load_sources ~dir ~files =
+let load_sources ~dune_version ~dir ~files =
   let init = C.Kind.Dict.make String.Map.empty in
   String.Set.fold files ~init ~f:(fun fn acc ->
-    match C.Kind.split_extension fn with
-    | None -> acc
-    | Some (obj, kind) ->
+    match C.Kind.split_extension fn ~dune_version with
+    | Unrecognized -> acc
+    | Not_allowed_until version ->
+      let loc = Loc.in_dir dir in
+      Errors.warn loc
+        "Source file %s with extension %s is not allowed before version %a"
+        fn (Filename.extension fn) Syntax.Version.pp version;
+      acc
+    | Recognized (obj, kind) ->
       let path = Path.relative dir fn in
       C.Kind.Dict.update acc kind ~f:(fun v ->
         String.Map.add v obj (C.Source.make ~kind ~path)
@@ -79,9 +85,11 @@ let make (d : _ Dir_with_dune.t)
             match String.Map.find c_sources s with
             | Some source -> (loc, source)
             | None ->
+              let dune_version = d.dune_version in
               Errors.fail loc "%s does not exist as a C source. \
                                %s must be present"
-                s (String.enumerate_one_of (C.Kind.possible_fns kind s))
+                s (String.enumerate_one_of
+                     (C.Kind.possible_fns kind s ~dune_version))
           )
         in
         let names =

src/c_sources.mli

@@ -12,7 +12,8 @@ val for_lib : t -> dir:Path.t -> name:Lib_name.t -> C.Sources.t
     map. The first level will is keyed by C vs. C++ sources. The second level is
     keyed by the object name of the source. *)
 val load_sources
-  :  dir:Path.t
+  :  dune_version:Syntax.Version.t
+  -> dir:Path.t
   -> files:String.Set.t
   -> C.Source.t String.Map.t C.Kind.Dict.t
 

src/dir_contents.ml

@@ -240,6 +240,7 @@ let load_text_files sctx ft_dir
       ; scope = _
       ; data = stanzas
       ; kind = _
+      ; dune_version = _
       } =
   (* Interpret a few stanzas in order to determine the list of
      files generated by the user. *)
@@ -355,8 +356,10 @@ let rec get sctx ~dir =
                               ~modules:(modules_of_files ~dir:d.ctx_dir ~files))
           ; mlds = lazy (build_mlds_map d ~files)
           ; c_sources = lazy (
+              let dune_version = d.dune_version in
               C_sources.make d
-                ~c_sources:(C_sources.load_sources ~dir:d.ctx_dir ~files))
+                ~c_sources:(C_sources.load_sources ~dune_version ~dir:d.ctx_dir
+                              ~files))
           }
         | Some (_, None)
         | None ->
@@ -422,11 +425,12 @@ let rec get sctx ~dir =
         Modules.make d ~modules)
       in
       let c_sources = lazy (
+        let dune_version = d.dune_version in
         let init = C.Kind.Dict.make String.Map.empty in
         let c_sources =
           List.fold_left ((dir, files) :: subdirs) ~init
             ~f:(fun acc (dir, files) ->
-              let sources = C_sources.load_sources ~dir ~files in
+              let sources = C_sources.load_sources ~dir ~dune_version ~files in
               let f acc sources =
                 String.Map.union acc sources ~f:(fun name x y ->
                   Errors.fail (Loc.in_file

src/dir_with_dune.ml

@@ -1,9 +1,10 @@
 open Stdune
 
 type 'data t =
-  { src_dir : Path.t
-  ; ctx_dir : Path.t
-  ; data    : 'data
-  ; scope   : Scope.t
-  ; kind    : Dune_lang.Syntax.t
+  { src_dir         : Path.t
+  ; ctx_dir         : Path.t
+  ; data            : 'data
+  ; scope           : Scope.t
+  ; kind            : Dune_lang.Syntax.t
+  ; dune_version    : Syntax.Version.t
   }

src/dir_with_dune.mli

@@ -2,9 +2,10 @@ open Stdune
 
 (** A directory with a [dune] file *)
 type 'data t =
-  { src_dir : Path.t
-  ; ctx_dir : Path.t  (** [_build/context-name/src_dir] *)
-  ; data    : 'data
-  ; scope   : Scope.t
-  ; kind    : Dune_lang.Syntax.t
+  { src_dir         : Path.t
+  ; ctx_dir         : Path.t  (** [_build/context-name/src_dir] *)
+  ; data            : 'data
+  ; scope           : Scope.t
+  ; kind            : Dune_lang.Syntax.t
+  ; dune_version    : Syntax.Version.t
   }

src/dune_project.ml

@@ -165,6 +165,7 @@ type t =
   ; extension_args  : Univ_map.t
   ; parsing_context : Univ_map.t
   ; implicit_transitive_deps : bool
+  ; dune_version    : Syntax.Version.t
   }
 
 let packages t = t.packages
@@ -177,7 +178,7 @@ let implicit_transitive_deps t = t.implicit_transitive_deps
 
 let pp fmt { name ; root ; version ; project_file ; parsing_context = _
            ; extension_args = _; stanza_parser = _ ; packages
-           ; implicit_transitive_deps } =
+           ; implicit_transitive_deps ; dune_version } =
   Fmt.record fmt
     [ "name", Fmt.const Name.pp name
     ; "root", Fmt.const Path.Local.pp root
@@ -189,6 +190,7 @@ let pp fmt { name ; root ; version ; project_file ; parsing_context = _
         (Package.Name.Map.to_list packages)
     ; "implicit_transitive_deps",
       Fmt.const Format.pp_print_bool implicit_transitive_deps
+    ; "dune_version", Fmt.const Syntax.Version.pp dune_version
     ]
 
 let find_extension_args t key =
@@ -422,14 +424,15 @@ let key =
   Univ_map.Key.create ~name:"dune-project"
     (fun { name; root; version; project_file
          ; stanza_parser = _; packages = _ ; extension_args = _
-         ; parsing_context ; implicit_transitive_deps } ->
+         ; parsing_context ; implicit_transitive_deps ; dune_version } ->
       Sexp.Encoder.record
         [ "name", Name.to_sexp name
         ; "root", Path.Local.to_sexp root
         ; "version", Sexp.Encoder.(option string) version
         ; "project_file", Project_file.to_sexp project_file
         ; "parsing_context", Univ_map.to_sexp parsing_context
         ; "implicit_transitive_deps", Sexp.Encoder.bool implicit_transitive_deps
+        ; "dune_version", Syntax.Version.to_sexp dune_version
         ])
 
 let set t = Dune_lang.Decoder.set key t
@@ -469,6 +472,7 @@ let anonymous = lazy (
   ; project_file
   ; extension_args
   ; parsing_context
+  ; dune_version = lang.version
   })
 
 let default_name ~dir ~packages =
@@ -537,6 +541,7 @@ let parse ~dir ~lang ~packages ~file =
      ; extension_args
      ; parsing_context
      ; implicit_transitive_deps
+     ; dune_version = lang.version
      })
 
 let load_dune_project ~dir packages =
@@ -565,6 +570,7 @@ let make_jbuilder_project ~dir packages =
   ; extension_args
   ; parsing_context
   ; implicit_transitive_deps = true
+  ; dune_version = lang.version
   }
 
 let read_name file =
@@ -603,5 +609,7 @@ let load ~dir ~files =
   else
     None
 
+let dune_version t = t.dune_version
+
 let set_parsing_context t parser =
   Dune_lang.Decoder.set_many t.parsing_context parser

src/dune_project.mli

@@ -125,4 +125,6 @@ val set_parsing_context : t -> 'a Dune_lang.Decoder.t -> 'a Dune_lang.Decoder.t
 
 val implicit_transitive_deps : t -> bool
 
+val dune_version : t -> Syntax.Version.t
+
 val pp : t Fmt.t

src/gen_rules.ml

@@ -69,7 +69,7 @@ module Gen(P : Install_rules.Params) = struct
 
   let gen_rules dir_contents cctxs
         { Dir_with_dune. src_dir; ctx_dir; data = stanzas
-        ; scope; kind = dir_kind } =
+        ; scope; kind = dir_kind ; dune_version = _ } =
     let expander = Super_context.expander sctx ~dir:ctx_dir in
     let for_stanza stanza =
       let dir = ctx_dir in

src/install_rules.ml

@@ -347,6 +347,7 @@ module Gen(P : Params) = struct
            ~f:(fun ({ Dir_with_dune.
                       data =
                         { Dune_file.Install_conf. section; files; package = _ }
+                    ; dune_version = _
                     ; ctx_dir = dir
                     ; src_dir = _
                     ; scope = _
@@ -380,6 +381,7 @@ module Gen(P : Params) = struct
                    ; ctx_dir = dir
                    ; src_dir = _
                    ; kind = dir_kind
+                   ; dune_version = _
                    } ->
                 let sub_dir = (Option.value_exn lib.public).sub_dir in
                 let dir_contents = Dir_contents.get sctx ~dir in

src/local_package.ml

@@ -19,7 +19,7 @@ let is_odig_doc_file fn =
 let add_stanzas t ~sctx =
   List.fold_left ~init:t
     ~f:(fun t ({ Dir_with_dune. ctx_dir = dir ; scope = _ ; data
-               ; src_dir = _ ; kind = _} as d) ->
+               ; src_dir = _ ; kind = _; dune_version = _ } as d) ->
          let expander = Super_context.expander sctx ~dir in
          let path_expander sw =
            (String_with_vars.loc sw, Expander.expand_str expander sw) in
@@ -45,7 +45,7 @@ let stanzas_to_consider_for_install stanzas ~external_lib_deps_mode =
   if not external_lib_deps_mode then
     List.concat_map stanzas
       ~f:(fun ({ Dir_with_dune.ctx_dir =  _; data = stanzas
-               ; scope; kind = _ ; src_dir = _ } as d) ->
+               ; scope; kind = _ ; src_dir = _ ; dune_version = _ } as d) ->
            List.filter_map stanzas ~f:(fun stanza ->
              let keep =
                match (stanza : Stanza.t) with

src/stanza.ml

@@ -9,7 +9,7 @@ end
 let syntax =
   Syntax.create ~name:"dune" ~desc:"the dune language"
     [ (0, 0) (* Jbuild syntax *)
-    ; (1, 7)
+    ; (1, 8)
     ]
 
 module File_kind = struct

src/super_context.ml

@@ -269,12 +269,14 @@ let create
     List.map stanzas
       ~f:(fun { Dune_load.Dune_file. dir; project; stanzas; kind } ->
         let ctx_dir = Path.append context.build_dir dir in
+        let dune_version = Dune_project.dune_version project in
         { Dir_with_dune.
           src_dir = dir
         ; ctx_dir
         ; data = stanzas
         ; scope = Scope.DB.find_by_name scopes (Dune_project.name project)
         ; kind
+        ; dune_version
         })
   in
   let stanzas_per_dir =

test/blackbox-tests/dune.inc

@@ -111,6 +111,14 @@
    test-cases/custom-build-dir
    (progn (run %{exe:cram.exe} -test run.t) (diff? run.t run.t.corrected)))))
 
+(alias
+ (name cxx-extension)
+ (deps (package dune) (source_tree test-cases/cxx-extension))
+ (action
+  (chdir
+   test-cases/cxx-extension
+   (progn (run %{exe:cram.exe} -test run.t) (diff? run.t run.t.corrected)))))
+
 (alias
  (name default-targets)
  (deps (package dune) (source_tree test-cases/default-targets))
@@ -1277,6 +1285,7 @@
   (alias copy_files)
   (alias cross-compilation)
   (alias custom-build-dir)
+  (alias cxx-extension)
   (alias default-targets)
   (alias dep-vars)
   (alias depend-on-the-universe)
@@ -1433,6 +1442,7 @@
   (alias copy_files)
   (alias cross-compilation)
   (alias custom-build-dir)
+  (alias cxx-extension)
   (alias default-targets)
   (alias dep-vars)
   (alias depend-on-the-universe)

test/blackbox-tests/test-cases/cxx-extension/bar.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include "foo.cxx"
+
+void foo () {
+  int n = cppfoo();
+  printf("n = %d\n", n);
+}

test/blackbox-tests/test-cases/cxx-extension/bar.ml

@@ -0,0 +1 @@
+Foo.foo ()

test/blackbox-tests/test-cases/cxx-extension/dune

@@ -0,0 +1,14 @@
+(library
+ (name foo)
+ (cxx_names foo)
+ (c_names bar)
+ (modules foo))
+
+(executable
+ (name bar)
+ (libraries foo)
+ (modules bar))
+
+(alias
+ (name default)
+ (action (run ./bar.exe)))

test/blackbox-tests/test-cases/cxx-extension/dune-project

@@ -0,0 +1 @@
+(lang dune 1.8)