unikernel/duniverse/ocaml-caqti/caqti/lib-platform-unix/driver_loader.ml

@@ -0,0 +1,56 @@
+(* Copyright (C) 2022--2024  Petter A. Urkedal <paurkedal@gmail.com>
+ *
+ * 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 3 of the License, or (at your
+ * option) any later version, with the LGPL-3.0 Linking Exception.
+ *
+ * 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
+ * and the LGPL-3.0 Linking Exception along with this library.  If not, see
+ * <http://www.gnu.org/licenses/> and <https://spdx.org>, respectively.
+ *)
+
+module type DRIVER_FUNCTOR =
+  functor (System : Caqti_platform.System_sig.S) ->
+  functor (_ : System_sig.S
+    with type 'a fiber := 'a System.Fiber.t
+     and type stdenv := System.stdenv) ->
+  Caqti_platform.Driver_loader.DRIVER
+    with type 'a fiber := 'a System.Fiber.t
+     and type ('a, 'err) stream := ('a, 'err) System.Stream.t
+     and type switch := System.Switch.t
+     and type stdenv := System.stdenv
+
+let drivers = Hashtbl.create 5
+let register scheme p = Hashtbl.add drivers scheme p
+
+module Make
+  (System : Caqti_platform.System_sig.S)
+  (System_unix : System_sig.S
+    with type 'a fiber := 'a System.Fiber.t
+     and type stdenv := System.stdenv) =
+struct
+  module Core_loader = Caqti_platform.Driver_loader.Make (System)
+
+  module type DRIVER = Core_loader.DRIVER
+  module type CONNECTION = Core_loader.CONNECTION
+
+  let provides_unix = true
+
+  let find_and_apply' scheme =
+    (match Hashtbl.find_opt drivers scheme with
+     | None -> None
+     | Some (module F : DRIVER_FUNCTOR) ->
+        let module Driver = F (System) (System_unix) in
+        Some (module Driver : DRIVER))
+
+  let find_and_apply scheme =
+    (match Core_loader.find_and_apply scheme with
+     | Some _ as r -> r
+     | None -> find_and_apply' scheme)
+end