unikernel/duniverse/ocaml-caqti/caqti-dynload/lib/caqti_dynload.ml

@@ -0,0 +1,52 @@
+(* Copyright (C) 2017--2018  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.
+ *)
+
+let debug =
+  try bool_of_string (Sys.getenv "CAQTI_DEBUG_DYNLOAD")
+  with Not_found -> false
+
+let backend_predicates () =
+  (match Sys.backend_type with
+   | Sys.Native -> ["native"]
+   | Sys.Bytecode -> ["byte"]
+   | Sys.Other _ -> [])
+
+let init = lazy begin
+  let predicates = backend_predicates () in
+  Findlib.init ();
+  Findlib.record_package_predicates predicates;
+  List.iter (Findlib.record_package Record_core)
+            (Findlib.package_deep_ancestors predicates ["caqti"]);
+  if debug then
+    Printf.eprintf "\
+        [DEBUG] Caqti_dynload: recorded_predicates = %s\n\
+        [DEBUG] Caqti_dynload: recorded_packages.core = %s\n\
+        [DEBUG] Caqti_dynload: recorded_packages.load = %s\n%!"
+      (String.concat " " (Findlib.recorded_predicates ()))
+      (String.concat " " (Findlib.recorded_packages Record_core))
+      (String.concat " " (Findlib.recorded_packages Record_load))
+end
+
+let () = Caqti_platform.Connector.define_loader @@ fun pkg ->
+  Lazy.force init;
+  if debug then
+    Printf.eprintf "[DEBUG] Caqti_dynload: requested package: %s\n" pkg;
+  (try Ok (Fl_dynload.load_packages ~debug [pkg]) with
+   | Dynlink.Error err -> Error (Dynlink.error_message err)
+   | Findlib.No_such_package (_pkg, info) -> Error info)
+
+module Weak_ = struct include Weak end (* for caqti-driver-mariadb *)