RNT interface

Co-authored-by: Estevan Castilho <tevo@riajuu.net>

1 files changed, 155 insertions, 0 deletions

diff --git a/lib/nt_ffi.ml b/lib/nt_ffi.ml
new file mode 100644
index 0000000..b7e65c4
--- /dev/null
+++ b/lib/nt_ffi.ml
@@ -0,0 +1,155 @@
+(* Low-level ctypes bindings to RNT_C_API.h.
+   This module is internal to Nt — never import it anywhere else. *)
+
+open Ctypes
+open Foreign
+
+(* Load the shared library.  Set RNT_LIBRARY_PATH to the full path of
+   libRNT.dylib / libRNT.so when the library is not on the default search
+   path. *)
+let lib =
+  let path =
+    match Sys.getenv_opt "RNT_LIBRARY_PATH" with
+    | Some p -> p
+    | None   -> "libRNT.dylib"
+  in
+  Dl.(dlopen ~filename:path ~flags:[ RTLD_NOW; RTLD_GLOBAL ])
+
+let fn name typ = foreign ~from:lib name typ
+
+(* Runtime ----------------------------------------------------------------- *)
+let rnt_init =
+  fn "rnt_init" (string @-> string @-> returning int)
+
+(* Auth -------------------------------------------------------------------- *)
+let rnt_firewall =
+  fn "rnt_firewall" (string @-> ptr (ptr char) @-> returning int)
+
+(* Session lifecycle ------------------------------------------------------- *)
+let rnt_session_open =
+  fn "rnt_session_open" (ptr void @-> ptr (ptr char) @-> returning int)
+
+let rnt_session_close =
+  fn "rnt_session_close" (string @-> returning int)
+
+let rnt_session_set_branch =
+  fn "rnt_session_set_branch"
+    (string @-> string @-> string @-> returning int)
+
+(* Handle lifecycle -------------------------------------------------------- *)
+let rnt_open_handle =
+  fn "rnt_open_handle" (string @-> ptr void @-> returning (ptr void))
+
+let rnt_close_handle =
+  fn "rnt_close_handle" (ptr void @-> returning int)
+
+(* Branch hash-pointer ----------------------------------------------------- *)
+let rnt_branch_target =
+  fn "rnt_branch_target"
+    (ptr void @-> ptr (ptr char) @-> returning int)
+
+let rnt_branch_advance =
+  fn "rnt_branch_advance" (string @-> string @-> returning int)
+
+(* Object registration ----------------------------------------------------- *)
+let rnt_register_relation =
+  fn "rnt_register_relation" (string @-> returning int)
+
+let rnt_register_branch =
+  fn "rnt_register_branch" (string @-> string @-> returning int)
+
+(* Branch / snapshot relation enumeration ----------------------------------- *)
+let rnt_list_relations =
+  fn "rnt_list_relations" (string @-> ptr (ptr char) @-> returning int)
+
+let rnt_list_branch_multigroups =
+  fn "rnt_list_branch_multigroups" (string @-> ptr (ptr char) @-> returning int)
+
+let rnt_list_snapshot_relations =
+  fn "rnt_list_snapshot_relations" (string @-> ptr (ptr char) @-> returning int)
+
+(* Tuple storage ----------------------------------------------------------- *)
+let rnt_link_tuple =
+  fn "rnt_link_tuple"
+    (string @-> string @-> ptr (ptr char) @-> returning int)
+
+let rnt_unlink_tuple =
+  fn "rnt_unlink_tuple" (string @-> string @-> returning int)
+
+let rnt_clear_relation =
+  fn "rnt_clear_relation" (string @-> returning int)
+
+let rnt_relation_root =
+  fn "rnt_relation_root"
+    (string @-> ptr (ptr char) @-> returning int)
+
+(* Cursor and VM ----------------------------------------------------------- *)
+let rnt_cursor_open =
+  fn "rnt_cursor_open" (ptr void @-> returning (ptr void))
+
+let rnt_cursor_next =
+  fn "rnt_cursor_next" (ptr void @-> ptr (ptr char) @-> returning int)
+
+let rnt_cursor_close =
+  fn "rnt_cursor_close" (ptr void @-> returning int)
+
+(* VM plan builder --------------------------------------------------------- *)
+let rnt_plan_scan =
+  fn "rnt_plan_scan" (string @-> returning (ptr void))
+
+let rnt_plan_join =
+  fn "rnt_plan_join" (ptr void @-> ptr void @-> returning (ptr void))
+
+let rnt_plan_take =
+  fn "rnt_plan_take" (ptr void @-> size_t @-> returning (ptr void))
+
+let rnt_plan_free =
+  fn "rnt_plan_free" (ptr void @-> returning void)
+
+let rnt_vm_execute_plan =
+  fn "rnt_vm_execute_plan" (ptr void @-> returning (ptr void))
+
+let rnt_vm_cursor_next =
+  fn "rnt_vm_cursor_next" (ptr void @-> ptr (ptr char) @-> returning int)
+
+let rnt_vm_cursor_close =
+  fn "rnt_vm_cursor_close" (ptr void @-> returning int)
+
+(* Memory management ------------------------------------------------------- *)
+let rnt_free_string =
+  fn "rnt_free_string" (ptr char @-> returning void)
+
+let rnt_free_bytes =
+  fn "rnt_free_bytes" (ptr uint8_t @-> returning void)
+
+(* --------------------------------------------------------------------------
+   Helpers shared by Nt (not exported from the library module)
+   -------------------------------------------------------------------------- *)
+
+let null_char_ptr : char ptr = from_voidp char null
+
+(* Reads a null-terminated C string from a char pointer, then frees it. *)
+let consume_cstring (p : char ptr) : string =
+  let n = ref 0 in
+  while !@(p +@ !n) <> '\000' do incr n done;
+  let s = string_from_ptr p ~length:!n in
+  rnt_free_string p;
+  s
+
+(* Allocates a char* out-parameter, calls [f], returns the rc and string. *)
+let with_out_string (f : char ptr ptr -> int) : int * string option =
+  let pp = allocate (ptr char) null_char_ptr in
+  let rc = f pp in
+  let p  = !@ pp in
+  if is_null p then (rc, None)
+  else (rc, Some (consume_cstring p))
+
+(* Converts a void* (returned from open_handle / cursor_open) to nativeint.
+   Returns None when the pointer is NULL (failure). *)
+let ptr_to_opt (p : unit ptr) : nativeint option =
+  if is_null p then None
+  else Some (raw_address_of_ptr p)
+
+(* Converts a stored nativeint back to a void* for API calls. *)
+let nint_to_ptr (n : nativeint) : unit ptr =
+  ptr_of_raw_address n