unikernel/duniverse/ocaml-caqti/caqti/lib-template/request.ml

@@ -0,0 +1,92 @@
+(* Copyright (C) 2017--2025  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.
+ *)
+
+[@@@alert "-caqti_private"]
+
+module Log = (val Logs.src_log (Logs.Src.create "caqti"))
+
+type prepare_policy =
+  | Direct
+  | Dynamic
+  | Static
+
+type ('a, 'b, +'m) t = {
+  id: int option;
+  prepare_policy: prepare_policy;
+  query: Dialect.t -> Query.t;
+  param_type: 'a Row_type.t;
+  row_type: 'b Row_type.t;
+  row_mult: 'm Row_mult.t;
+} constraint 'm = [< `Zero | `One | `Many]
+
+let last_id = ref (-1)
+
+let create prepare_policy (param_type, row_type, row_mult) query =
+  let id =
+    (match prepare_policy with
+     | Direct -> None
+     | Static | Dynamic -> incr last_id; Some !last_id)
+  in
+  {id; prepare_policy; query; param_type; row_type; row_mult}
+
+let prepare_policy request = request.prepare_policy
+let param_type request = request.param_type
+let row_type request = request.row_type
+let row_mult request = request.row_mult
+
+let query_id request = request.id
+let query request = request.query
+
+let empty_subst _ = raise Not_found
+
+let default_dialect = Dialect.create_unknown ~purpose:`Printing ()
+
+let make_pp ?(dialect = default_dialect) ?(subst = empty_subst) () ppf req =
+  let query = Query.expand subst (req.query dialect) in
+  Format.fprintf ppf "(%a -->%s %a) {|%a|}"
+    Row_type.pp req.param_type
+    (match Row_mult.expose req.row_mult with
+     | `Zero -> "."
+     | `One -> ""
+     | `Zero_or_one -> "?"
+     | `Zero_or_more -> "*")
+    Row_type.pp req.row_type
+    Query.pp query
+
+let pp ppf = make_pp () ppf
+
+let pp_with_param_enabled =
+  (match Sys.getenv "CAQTI_DEBUG_PARAM" with
+   | "true" -> true
+   | "false" -> false
+   | s ->
+      Log.err (fun f ->
+        f "Invalid value %s for CAQTI_DEBUG_PARAM, assuming false." s);
+      false
+   | exception Not_found -> false)
+
+let make_pp_with_param ?dialect ?subst () ppf (req, param) =
+  let pp = make_pp ?subst ?dialect () in
+  pp ppf req;
+  if pp_with_param_enabled then
+    Format.fprintf ppf " %a" (Row.pp req.param_type) param
+
+type liveness_witness = int option
+
+let liveness_witness request =
+  assert (request.id <> None);
+  request.id