[cpp] Add magic GENCPP_SOURCE_DIRECTORY variable to make native code interaction easier

gencpp.ml

@@ -347,7 +347,7 @@ let get_meta_string meta key =
 
 
 
-let get_meta_string_path ctx meta key =
+let get_meta_string_path meta key =
    let rec loop = function
       | [] -> ""
       | (k,[Ast.EConst (Ast.String name),_], pos) :: _  when k=key->
@@ -367,6 +367,28 @@ let get_meta_string_path ctx meta key =
    loop meta
 ;;
 
+
+let get_meta_string_full_filename meta key =
+   let rec loop = function
+      | [] -> ""
+      | (k,_, pos) :: _  when k=key->
+           if (Filename.is_relative pos.pfile) then
+              Gencommon.normalize (Filename.concat (Sys.getcwd()) pos.pfile)
+           else
+              pos.pfile
+      | _ :: l -> loop l
+      in
+   loop meta
+;;
+
+let get_meta_string_full_dirname meta key =
+   let name = get_meta_string_full_filename meta key in
+   try
+      Gencommon.normalize (Filename.dirname name)
+   with Invalid_argument _ -> ""
+;;
+
+
 let get_field_access_meta field_access key =
 match field_access with
    | FInstance(_,_,class_field)
@@ -376,6 +398,14 @@ match field_access with
 
 let get_code meta key =
    let code = get_meta_string meta key in
+   let magic_var = "${GENCPP_SOURCE_DIRECTORY}"  in
+   let code = if ExtString.String.exists code magic_var then begin
+         let source_directory = get_meta_string_full_dirname meta key in
+         let _,code = ExtString.String.replace code magic_var source_directory in
+         code
+      end else
+         code
+      in
    if (code<>"") then code ^ "\n" else code
 ;;
 
@@ -2741,7 +2771,7 @@ let find_referenced_types ctx obj super_deps constructor_deps header_only for_de
       end
    in
    let add_extern_class klass =
-      let include_file = get_meta_string_path ctx klass.cl_meta (if for_depends then Meta.Depend else Meta.Include) in
+      let include_file = get_meta_string_path klass.cl_meta (if for_depends then Meta.Depend else Meta.Include) in
       if (include_file<>"") then
          add_type ( path_of_string include_file )
       else if (not for_depends) && (has_meta_key klass.cl_meta Meta.Include) then
@@ -3463,7 +3493,7 @@ let generate_class_files common_ctx member_types super_deps constructor_deps cla
       output_cpp "#include <hx/Scriptable.h>\n";
 
    output_cpp ( get_class_code class_def Meta.CppFileCode );
-   let inc = get_meta_string_path ctx class_def.cl_meta Meta.CppInclude in
+   let inc = get_meta_string_path class_def.cl_meta Meta.CppInclude in
    if (inc<>"") then
       output_cpp ("#include \"" ^ inc ^ "\"\n");
 
@@ -4086,7 +4116,7 @@ let generate_class_files common_ctx member_types super_deps constructor_deps cla
    List.iter ( gen_forward_decl h_file ) referenced;
 
    output_h ( get_class_code class_def Meta.HeaderCode );
-   let inc = get_meta_string_path ctx class_def.cl_meta Meta.HeaderInclude in
+   let inc = get_meta_string_path class_def.cl_meta Meta.HeaderInclude in
    if (inc<>"") then
       output_h ("#include \"" ^ inc ^ "\"\n");
 
@@ -5480,7 +5510,7 @@ let generate_source common_ctx =
       (match object_def with
       | TClassDecl class_def when is_extern_class class_def ->
          build_xml := !build_xml ^ (get_class_code class_def Meta.BuildXml);
-         let source = get_meta_string_path common_ctx class_def.cl_meta Meta.SourceFile in
+         let source = get_meta_string_path class_def.cl_meta Meta.SourceFile in
          if (source<>"") then
             extern_src := source :: !extern_src;
       | TClassDecl class_def ->