unikernel/duniverse/ocaml-caqti/caqti-eio/lib-unix/system_unix.ml

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+(* Copyright (C) 2022--2023  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.
+ *)
+
+include Caqti_eio.System
+
+module Unix = struct
+  type file_descr = Unix.file_descr
+
+  let wrap_fd f fd = f fd
+
+  let poll ~stdenv ?(read = false) ?(write = false) ?timeout fd =
+    let f () =
+      (match read, write with
+       | false, false ->
+          (false, false, false)
+       | true, true ->
+          Eio.Fiber.first
+            (fun () -> Eio_unix.await_readable fd; (true, false, false))
+            (fun () -> Eio_unix.await_writable fd; (false, true, false))
+       | true, false ->
+          Eio_unix.await_readable fd; (true, false, false)
+       | false, true ->
+          Eio_unix.await_writable fd; (false, true, false))
+    in
+    (match timeout with
+     | None -> f ()
+     | Some t ->
+        (match Eio.Time.with_timeout stdenv#clock t (fun () -> Ok (f ())) with
+         | Ok r -> r
+         | Error `Timeout -> (false, false, true)))
+end
+
+module Preemptive = struct
+  let detach f x = Eio_unix.run_in_systhread (fun () -> f x)
+  let run_in_main f = f () (* FIXME *)
+end