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(* hey emacs, this is OCaml code: -*- tuareg -*- *)
(* nbd client library in userspace: generator
* Copyright Tage Johansson
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*)
(* Low level Rust bindings for the libnbd-sys crate. *)
open Printf
open API
open Utils
(** A list of the argument types corresponding to an [arg]. *)
let arg_types : arg -> string list = function
| Bool n -> [ "bool" ]
| Int n | Fd n | Enum (n, _) -> [ "c_int" ]
| UInt n -> [ "c_uint" ]
| UIntPtr n -> [ "uintptr_t" ]
| SizeT n -> [ "size_t" ]
| UInt32 n | Flags (n, _) -> [ "u32" ]
| Int64 n -> [ "i64" ]
| UInt64 n -> [ "u64" ]
| String n | Path n -> [ "*const c_char" ]
| SockAddrAndLen (n1, n2) -> [ "*const sockaddr"; "socklen_t" ]
| StringList n -> [ "*mut *mut c_char" ]
| BytesIn (n1, n2) | BytesPersistIn (n1, n2) -> [ "*const c_void"; "usize" ]
| BytesOut (n1, n2) | BytesPersistOut (n1, n2) -> [ "*mut c_void"; "usize" ]
| Closure { cbname } -> [ sprintf "nbd_%s_callback" cbname ]
| Extent64 (_) -> [ "nbd_extent" ]
(** The type of an optional argument. *)
let optarg_type : optarg -> string = function
| OClosure { cbname } -> sprintf "nbd_%s_callback" cbname
| OFlags _ -> "u32"
(** The types of arguments corresponding to a [cbarg]. *)
let cbarg_types : cbarg -> string list = function
| CBInt n -> arg_types (Int n)
| CBUInt n -> arg_types (UInt n)
| CBInt64 n -> arg_types (Int64 n)
| CBUInt64 n -> arg_types (UInt64 n)
| CBString n -> arg_types (String n)
| CBBytesIn (n1, n2) -> arg_types (BytesIn (n1, n2))
| CBMutable arg -> arg_types arg |> List.map (fun x -> "*mut " ^ x)
| CBArrayAndLen (elem, _) ->
let elem_type =
match arg_types elem with
| [ x ] -> x
| _ -> failwith "Bad array element type"
in
[ sprintf "*mut %s" elem_type; "usize" ]
(** Get a return type. *)
let ret_type : ret -> string = function
| RBool -> "c_int"
| RStaticString -> "*const c_char"
| RInt | RErr | RFd | REnum _ -> "c_int"
| RInt64 | RCookie -> "i64"
| RSizeT -> "isize"
| RString -> "*mut c_char"
| RUInt -> "c_uint"
| RUInt64 -> "u64"
| RUIntPtr -> "uintptr_t"
| RFlags _ -> "u32"
(** The names of all arguments corresponding to an [arg]. *)
let arg_names : arg -> string list = function
| Bool n
| Int n
| UInt n
| UIntPtr n
| UInt32 n
| Int64 n
| UInt64 n
| SizeT n
| String n
| StringList n
| Path n
| Fd n
| Enum (n, _)
| Flags (n, _)
| Closure { cbname = n } ->
[ n ]
| SockAddrAndLen (n1, n2)
| BytesIn (n1, n2)
| BytesPersistIn (n1, n2)
| BytesOut (n1, n2)
| BytesPersistOut (n1, n2) ->
[ n1; n2 ]
| Extent64 _ -> assert false (* only used in extent64_closure *)
(** The name of an optional argument. *)
let optarg_name : optarg -> string = function
| OClosure { cbname = name } | OFlags (name, _, _) -> name
(** Print the struct for a closure. *)
let print_closure_struct { cbname; cbargs } =
pr "#[repr(C)]\n";
pr "#[derive(Debug, Clone, Copy)]\n";
pr "pub struct nbd_%s_callback {\n" cbname;
pr " pub callback: \n";
pr " Option<unsafe extern \"C\" fn(*mut c_void, %s) -> c_int>,\n"
(cbargs |> List.map cbarg_types |> List.flatten |> String.concat ", ");
pr " pub user_data: *mut c_void,\n";
pr " pub free: Option<unsafe extern \"C\" fn(*mut c_void)>,\n";
pr "}\n"
(** Print an "extern definition" for a handle call. *)
let print_handle_call (name, call) =
let args_names =
(call.args |> List.map arg_names |> List.flatten)
@ (call.optargs |> List.map optarg_name)
in
let args_types =
(call.args |> List.map arg_types |> List.flatten)
@ (call.optargs |> List.map optarg_type)
in
pr "pub fn nbd_%s(handle: *mut nbd_handle, %s) -> %s;\n" name
(List.map2 (fun n ty -> sprintf "%s: %s" n ty) args_names args_types
|> String.concat ", ")
(ret_type call.ret)
(** Print a definition of "nbd_handle" and "nbd_extent" types. *)
let print_types () =
pr "#[repr(C)]\n";
pr "#[derive(Debug, Clone, Copy)]\n";
pr "pub struct nbd_handle {\n";
pr " _unused: [u8; 0],\n";
pr "}\n";
pr "\n";
pr "#[repr(C)]\n";
pr "#[derive(Debug, Clone, Copy)]\n";
pr "pub struct nbd_extent {\n";
pr " length: u64,\n";
pr " flags: u64,\n";
pr "}\n";
pr "\n"
(** Print some more "extern definitions". *)
let print_more_defs () =
pr "extern \"C\" {\n";
pr "pub fn nbd_get_error() -> *const c_char;\n";
pr "pub fn nbd_get_errno() -> c_int;\n";
pr "pub fn nbd_create() -> *mut nbd_handle;\n";
pr "pub fn nbd_close(h: *mut nbd_handle);\n";
pr "}\n";
pr "\n"
let print_imports () =
pr "use libc::*;\n";
pr "use std::ffi::c_void;\n";
pr "\n"
let generate_rust_sys_bindings () =
generate_header CStyle ~copyright:"Tage Johansson";
pr "\n";
print_imports ();
print_types ();
print_more_defs ();
all_closures |> List.iter print_closure_struct;
pr "extern \"C\" {\n";
handle_calls |> List.iter print_handle_call;
pr "}\n\n"
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