Re: [Libguestfs] [libnbd RFC PATCH 9/8] wip: generator: Add ReadStatus enum type

Exploration of what it would take to treat the nbd_pread_callback status parameter as a language-appropriate enum rather than a bare integer. While I've identified a rough set of the places to change, I have not actually got it working with Python or OCaml bindings. --- Posting this more for an idea of whether we want to pursue it further. I have no hard feelings if we decide to ditch it; what's more, compilers don't necessarily guarantee ABI stability with enum types in public headers, so sticking to Int may be better after all.

generator/generator | 46 +++++++++++++++++++++++++++++++++++++++------ 1 file changed, 40 insertions(+), 6 deletions(-) diff --git a/generator/generator b/generator/generator index 630260b..d269a04 100755 --- a/generator/generator +++ b/generator/generator @@ -845,6 +845,7 @@ and arg = | Int64 of string (* 64 bit signed int *) | Opaque of string (* opaque object, void* in C *) | Path of string (* filename or path *) +| ReadStatus of string (* enum of pread_callback status *) | SockAddrAndLen of string * string (* struct sockaddr * + socklen_t *) | String of string (* string *) | StringList of string (* argv-style NULL-terminated array of strings *) @@ -2033,10 +2034,13 @@ let constants = [ "CMD_FLAG_NO_HOLE", 1 lsl 1; "CMD_FLAG_DF", 1 lsl 2; "CMD_FLAG_REQ_ONE", 1 lsl 3; - - "READ_DATA", 1; - "READ_HOLE", 2; - "READ_ERROR", 3; +] +let enums = [ + "nbd_read_status", [ + "READ_DATA", 1; + "READ_HOLE", 2; + "READ_ERROR", 3; + ]; ]

(*----------------------------------------------------------------------*) @@ -2812,6 +2816,7 @@ let rec name_of_arg = function | Int64 n -> [n] | Opaque n -> [n] | Path n -> [n] +| ReadStatus n -> [n] | SockAddrAndLen (n, len) -> [n; len] | String n -> [n] | StringList n -> [n] @@ -2845,6 +2850,7 @@ let rec print_c_arg_list ?(handle = false) args = | Int n -> pr "int %s" n | Int64 n -> pr "int64_t %s" n | Opaque n -> pr "void *%s" n + | ReadStatus n -> pr "enum nbd_read_status %s" n | Path n | String n -> pr "const char *%s" n | StringList n -> pr "char **%s" n @@ -2896,6 +2902,13 @@ let generate_include_libnbd_h () = pr "\n"; List.iter (fun (n, i) -> pr "#define LIBNBD_%-30s %d\n" n i) constants; pr "\n"; + List.iter ( + fun (name, list) -> + pr "enum %s {\n" name; + List.iter (fun (n, i) -> pr " LIBNBD_%-30s = %d,\n" n i) list; + pr "};\n" + ) enums; + pr "\n"; pr "extern struct nbd_handle *nbd_create (void);\n"; pr "#define LIBNBD_HAVE_NBD_CREATE 1\n"; pr "\n"; @@ -3367,6 +3380,7 @@ let print_python_binding name { args; ret } = | Int _ -> () | Opaque n -> pr " struct %s_%s_data *_data = %s;\n" name cb_name n + | ReadStatus n | String n | UInt64 n -> () (* The following not yet implemented for callbacks XXX *) @@ -3384,6 +3398,7 @@ let print_python_binding name { args; ret } = | BytesIn (n, len) -> pr " \"y#\"" | Int n -> pr " \"i\"" | Opaque n -> pr " \"O\"" + | ReadStatus n -> pr " XXX1" | String n -> pr " \"s\"" | UInt64 n -> pr " \"K\"" (* The following not yet implemented for callbacks XXX *) @@ -3398,6 +3413,7 @@ let print_python_binding name { args; ret } = | ArrayAndLen (UInt32 n, _) -> pr ", py_%s" n | BytesIn (n, len) -> pr ", %s, (int) %s" n len | Opaque _ -> pr ", _data->data" + | ReadStatus n -> pr ", XXX2 %s" n | Int n | String n | UInt64 n -> pr ", %s" n @@ -3436,6 +3452,7 @@ let print_python_binding name { args; ret } = | BytesIn _ | Int _ | Opaque _ + | ReadStatus _ | String _ | UInt64 _ -> () (* The following not yet implemented for callbacks XXX *) @@ -3497,6 +3514,7 @@ let print_python_binding name { args; ret } = pr " long long %s; /* really int64_t */\n" n | Opaque _ -> () | Path n -> pr " char *%s = NULL;\n" n + | ReadStatus n -> pr " XXX3 %s\n" n | SockAddrAndLen (n, _) -> pr " /* XXX Complicated - Python uses a tuple of different\n"; pr " * lengths for the different socket types.\n"; @@ -3537,6 +3555,7 @@ let print_python_binding name { args; ret } = | Int64 _ | Opaque _ | Path _ + | ReadStatus _ | SockAddrAndLen _ | String _ | StringList _ @@ -3561,6 +3580,7 @@ let print_python_binding name { args; ret } = | Int64 n -> pr " \"L\"" | Opaque _ -> pr " \"O\"" | Path n -> pr " \"O&\"" + | ReadStatus n -> pr " XXX4" | SockAddrAndLen (n, _) -> pr " \"O\"" | String n -> pr " \"s\"" | StringList n -> pr " \"O\"" @@ -3584,6 +3604,7 @@ let print_python_binding name { args; ret } = | Int n -> pr ", &%s" n | Int64 n -> pr ", &%s" n | Opaque n -> pr ", &%s_data->data" (find_callback n) + | ReadStatus n -> pr ", XXX5 &%s" n | Path n -> pr ", PyUnicode_FSConverter, &%s" n | SockAddrAndLen (n, _) -> pr ", &%s" n | String n -> pr ", &%s" n @@ -3634,6 +3655,7 @@ let print_python_binding name { args; ret } = | Int64 n -> pr " %s_i64 = %s;\n" n n | Opaque n -> () | Path _ -> () + | ReadStatus n -> pr " XXX6 %s\n" n | SockAddrAndLen _ -> pr " abort (); /* XXX SockAddrAndLen not implemented */\n"; | String _ -> () @@ -3662,6 +3684,7 @@ let print_python_binding name { args; ret } = | Int64 n -> pr ", %s_i64" n | Opaque n -> pr ", %s_data" (find_callback n) | Path n -> pr ", %s" n + | ReadStatus n -> pr ", XXX8 %s" n | SockAddrAndLen (n, _) -> pr ", /* XXX */ (void *) %s, 0" n | String n -> pr ", %s" n | StringList n -> pr ", %s" n @@ -3696,6 +3719,7 @@ let print_python_binding name { args; ret } = | Int64 _ | Opaque _ | Path _ + | ReadStatus _ | SockAddrAndLen _ | String _ | StringList _ @@ -3741,6 +3765,7 @@ let print_python_binding name { args; ret } = | Int64 _ -> () | Opaque _ -> () | Path n -> pr " free (%s);\n" n + | ReadStatus _ -> () | SockAddrAndLen _ -> () | String n -> () | StringList n -> pr " nbd_internal_py_free_string_list (%s);\n" n @@ -3795,6 +3820,7 @@ import libnbdmod "; List.iter (fun (n, i) -> pr "%-30s = %d\n" n i) constants; + (* how to represent enums? *) pr "\ @@ -3839,6 +3865,7 @@ class NBD (object): | Int64 n -> n, None | Opaque n -> n, None | Path n -> n, None + | ReadStatus n -> n, None | SockAddrAndLen (n, _) -> n, None | String n -> n, None | StringList n -> n, None @@ -3929,6 +3956,7 @@ and ocaml_arg_to_string = function | OCamlArg (Int64 _) -> "int64" | OCamlArg (Opaque n) -> sprintf "'%s" n | OCamlArg (Path _) -> "string" + | OCamlArg (ReadStatus _) -> "int" | OCamlArg (SockAddrAndLen _) -> "string" (* XXX not impl *) | OCamlArg (String _) -> "string" | OCamlArg (StringList _) -> "string list" @@ -3978,6 +4006,7 @@ exception Closed of string List.iter ( fun (n, _) -> pr "val %s : int32\n" (String.lowercase_ascii n) ) constants; + (* how to represent enums? *) pr "\n"; pr "\ @@ -4040,6 +4069,7 @@ let () = List.iter ( fun (n, i) -> pr "let %s = %d_l\n" (String.lowercase_ascii n) i ) constants; + (* how to represent enums? *)

pr "\n"; pr "\ @@ -4092,7 +4122,7 @@ let print_ocaml_binding (name, { args; ret }) = List.map ( function | ArrayAndLen (UInt32 n, _) | BytesIn (n, _) - | Int n | Opaque n | String n | UInt64 n -> + | Int n | Opaque n | ReadStatus n | String n | UInt64 n -> n ^ "v" (* The following not yet implemented for callbacks XXX *) | ArrayAndLen _ | Bool _ | BytesOut _ @@ -4124,7 +4154,8 @@ let print_ocaml_binding (name, { args; ret }) = | BytesIn (n, len) -> pr " %sv = caml_alloc_string (%s);\n" n len; pr " memcpy (String_val (%sv), %s, %s);\n" n n len - | Int n -> + | Int n + | ReadStatus n -> pr " %sv = caml_copy_int32 (%s);\n" n n

| String n -> pr " %sv = caml_copy_string (%s);\n" n n @@ -4282,6 +4313,8 @@ let print_ocaml_binding (name, { args; ret }) = ) | OCamlArg (Path n) | OCamlArg (String n) -> pr " const char *%s = String_val (%sv);\n" n n + | OCamlArg (ReadStatus n) -> + pr " unsigned %s = Int_val (%sv);\n" n n

| OCamlArg (SockAddrAndLen (n, len)) -> pr " const struct sockaddr *%s;\n" n; pr " socklen_t %s;\n" len; @@ -4363,6 +4396,7 @@ let print_ocaml_binding (name, { args; ret }) = | OCamlArg (Int64 _) | OCamlArg (Opaque _) | OCamlArg (Path _) + | OCamlArg (ReadStatus _) | OCamlArg (String _) | OCamlArg (SockAddrAndLen _) | OCamlArg (UInt _) -- 2.20.1 _______________________________________________ Libguestfs mailing list Libguestfs(a)redhat.com https://www.redhat.com/mailman/listinfo/libguestfs