Add set_single_row_mode and extend result_status as needed.

Author: paurkedal

examples/async.ml

@@ -53,7 +53,17 @@ let main () =
   for i = 0 to r#ntuples - 1 do
     Printf.printf "%s %s %s\n"
                   (r#getvalue i 0) (r#getvalue i 1) (r#getvalue i 2)
-  done
+  done;
+  c#send_query_prepared "test_sel";
+  for i = 0 to 1 do
+    match fetch_result c with
+    | None -> assert false
+    | Some r ->
+      assert (r#status = Single_tuple);
+      Printf.printf "%s %s %s\n"
+                    (r#getvalue i 0) (r#getvalue i 1) (r#getvalue i 2)
+  done;
+  assert (fetch_result c = None)
 
 let _ =
   try main () with

examples/prompt.ml

@@ -39,6 +39,8 @@ let print_res conn res =
   | Bad_response -> printf "Bad response: %s\n" res#error; conn#reset
   | Nonfatal_error -> printf "Non fatal error: %s\n" res#error
   | Fatal_error -> printf "Fatal error: %s\n" res#error
+  | Copy_both -> printf "Copy in/out, not handled!\n"; exit 1
+  | Single_tuple -> printf "Single tuple, not handled!\n"; exit 1
 
 let rec dump_res conn =
   match conn#get_result with

lib/postgresql.ml

@@ -260,6 +260,8 @@ type result_status =
   | Bad_response
   | Nonfatal_error
   | Fatal_error
+  | Copy_both
+  | Single_tuple
 
 external result_status : result_status -> string = "PQresStatus_stub"
 
@@ -406,6 +408,7 @@ module Stub = struct
   external send_describe_portal : connection -> string -> int
     = "PQsendDescribePortal_stub"
 
+  external set_single_row_mode : connection -> int = "PQsetSingleRowMode_stub"
   external get_result : connection -> result = "PQgetResult_stub"
   external consume_input : connection -> int = "PQconsumeInput_stub" "noalloc"
   external is_busy : connection -> bool = "PQisBusy_stub" "noalloc"
@@ -811,13 +814,15 @@ object (self)
 
   method send_describe_prepared stm_name =
     wrap_conn (fun conn ->
-      if Stub.send_describe_prepared conn stm_name <> 1 then
-        signal_error conn)
+      if Stub.send_describe_prepared conn stm_name <> 1 then signal_error conn)
 
   method send_describe_portal portal_name =
     wrap_conn (fun conn ->
-      if Stub.send_describe_portal conn portal_name <> 1 then
-        signal_error conn)
+      if Stub.send_describe_portal conn portal_name <> 1 then signal_error conn)
+
+  method set_single_row_mode =
+    wrap_conn (fun conn ->
+      if Stub.set_single_row_mode conn <> 1 then signal_error conn)
 
   method get_result =
     let res = wrap_conn Stub.get_result in

lib/postgresql.mli

@@ -117,6 +117,8 @@ type result_status =
   | Bad_response    (** The server's response was not understood *)
   | Nonfatal_error
   | Fatal_error
+  | Copy_both
+  | Single_tuple    (** One tuple of a result set ({!set_single_row_mode}) *)
 
 (** Result of getline *)
 type getline_result =
@@ -631,6 +633,10 @@ object
 
       @raise Error if there is a connection error. *)
 
+  method set_single_row_mode : unit
+  (** [#set_single_row_mode] called right after {!send_query} or a sibling
+      function causes the returned rows to be split into individual results. *)
+
   method get_result : result option
   (** [get_result] @return [Some result] of an asynchronous query if
       available or [None].

lib/postgresql_stubs.c

@@ -36,6 +36,10 @@
     || ( PG_OCAML_MAJOR_VERSION >= 8 && PG_OCAML_MINOR_VERSION >= 2)
 # define PG_OCAML_8_2
 #endif
+#if PG_OCAML_MAJOR_VERSION > 9 \
+    || ( PG_OCAML_MAJOR_VERSION >= 9 && PG_OCAML_MINOR_VERSION >= 2)
+# define PG_OCAML_9_2
+#endif
 
 #include <string.h>
 #include <ctype.h>
@@ -817,6 +821,17 @@ PQsendDescribePortal_stub(value __unused v_conn, value __unused v_portal_name)
 }
 #endif
 
+#ifdef PG_OCAML_9_2
+noalloc_conn_info(PQsetSingleRowMode, Val_int)
+#else
+CAMLprim value
+PQsetSingleRowMode_stub(value __unused conn)
+{
+  caml_failwith("Postgresql.set_single_row_mode: not supported");
+  return Val_unit;
+}
+#endif
+
 CAMLprim value PQgetResult_stub(value v_conn)
 {
   CAMLparam1(v_conn);