From 91b39a095b1860bf5446251de184bfb94c32eb1a Mon Sep 17 00:00:00 2001
From: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Date: Mon, 20 May 2024 15:38:37 +0100
Subject: [PATCH 1/8] xapi-stdext-std: String.split's ~limit is not optional

Users can instead opt for Astring.String's or stdlib's functions.

Signed-off-by: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Signed-off-by: Pau Ruiz Safont <pau.safont@vates.tech>
---
 doc/content/xapi/cli/_index.md                |  2 +-
 ocaml/database/parse_db_conf.ml               |  4 +--
 .../lib/xapi-stdext-std/xstringext.ml         | 25 +++++++--------
 .../lib/xapi-stdext-std/xstringext.mli        |  2 +-
 .../lib/xapi-stdext-std/xstringext_test.ml    | 31 +++++--------------
 ocaml/quicktest/quicktest_http.ml             |  2 +-
 ocaml/rrd2csv/src/rrd2csv.ml                  |  4 +--
 ocaml/xapi/authx.ml                           |  4 ++-
 ocaml/xapi/config_file_sync.ml                |  3 +-
 ocaml/xapi/dbsync_slave.ml                    |  6 ++--
 ocaml/xapi/gpg.ml                             |  4 +--
 ocaml/xapi/map_check.ml                       |  2 +-
 ocaml/xapi/nm.ml                              |  2 +-
 ocaml/xapi/vhd_tool_wrapper.ml                |  4 +--
 ocaml/xapi/xapi_globs.ml                      |  5 +--
 ocaml/xapi/xapi_pif.ml                        |  6 ++--
 ocaml/xapi/xapi_pool_update.ml                |  2 +-
 ocaml/xapi/xapi_xenops.ml                     | 12 ++++---
 ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml |  2 +-
 .../bin/rrdp-squeezed/rrdp_squeezed.ml        |  4 ++-
 ocaml/xe-cli/newcli.ml                        |  2 +-
 21 files changed, 61 insertions(+), 67 deletions(-)

diff --git a/doc/content/xapi/cli/_index.md b/doc/content/xapi/cli/_index.md
index 6715e7288c0..093e1576aaf 100644
--- a/doc/content/xapi/cli/_index.md
+++ b/doc/content/xapi/cli/_index.md
@@ -156,7 +156,7 @@ So each function receives a printer for sending text output to the xe client, an
       let mac = List.assoc_default "mac" params "" in
       let network = Client.Network.get_by_uuid rpc session_id network in
       let pifs = List.assoc "pif-uuids" params in
-      let uuids = String.split ',' pifs in
+      let uuids = String.split_on_char ',' pifs in
       let pifs = List.map (fun uuid -> Client.PIF.get_by_uuid rpc session_id uuid) uuids in
       let mode = Record_util.bond_mode_of_string (List.assoc_default "mode" params "") in
       let properties = read_map_params "properties" params in
diff --git a/ocaml/database/parse_db_conf.ml b/ocaml/database/parse_db_conf.ml
index 67aa5c70d80..76deca97e42 100644
--- a/ocaml/database/parse_db_conf.ml
+++ b/ocaml/database/parse_db_conf.ml
@@ -110,7 +110,7 @@ let parse_db_conf s =
     let conf = Unixext.string_of_file s in
     let lines : string list ref = ref [] in
     let consume_line () = lines := List.tl !lines in
-    lines := String.split '\n' conf ;
+    lines := String.split_on_char '\n' conf ;
     List.iter (fun line -> debug "%s" line) !lines ;
     let read_block () =
       let path_line = List.hd !lines in
@@ -120,7 +120,7 @@ let parse_db_conf s =
       while !lines <> [] && List.hd !lines <> "" do
         let line = List.hd !lines in
         key_values :=
-          ( match String.split ':' line with
+          ( match String.split_on_char ':' line with
           | k :: vs ->
               ( String.lowercase_ascii k
               , String.lowercase_ascii (String.concat ":" vs)
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
index 4e5379d7b36..6c759498def 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
@@ -76,15 +76,18 @@ module String = struct
     in
     loop 0
 
-  let rec split ?(limit = -1) c s =
-    let i = match index_opt s c with Some x -> x | None -> -1 in
-    let nlimit = if limit = -1 || limit = 0 then limit else limit - 1 in
-    if i = -1 || nlimit = 0 then
-      [s]
-    else
-      let a = String.sub s 0 i
-      and b = String.sub s (i + 1) (String.length s - i - 1) in
-      a :: split ~limit:nlimit c b
+  let sub_to_end s start =
+    let length = String.length s in
+    String.sub s start (length - start)
+
+  let rec split ~limit sep s =
+    match (String.index_opt s sep, limit < 2) with
+    | None, _ | _, true ->
+        [s]
+    | Some pos, false ->
+        let first = String.sub s 0 pos in
+        let rest = sub_to_end s (pos + 1) in
+        first :: split ~limit:(limit - 1) sep rest
 
   let rtrim s =
     let n = String.length s in
@@ -185,10 +188,6 @@ module String = struct
     | Some rules ->
         map_unlikely s (fun c -> List.assoc_opt c rules)
 
-  let sub_to_end s start =
-    let length = String.length s in
-    String.sub s start (length - start)
-
   let sub_before c s = String.sub s 0 (String.index s c)
 
   let sub_after c s = sub_to_end s (String.index s c + 1)
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
index 1f27490493d..d68e3f524f8 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
@@ -42,7 +42,7 @@ module String : sig
       runs of characters where the predicate was true. Avoid if possible, it's
       very costly to execute. *)
 
-  val split : ?limit:int -> char -> string -> string list
+  val split : limit:int -> char -> string -> string list
   (** split a string on a single char *)
 
   val rtrim : string -> string
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
index 9b7eb2674a1..4a70eb31899 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
@@ -44,30 +44,13 @@ let test_rev_map =
   ("rev_map", tests)
 
 let test_split =
-  let test ?limit (splitter, splitted, expected) =
-    let split, name =
-      match limit with
-      | None ->
-          let name = Printf.sprintf {|'%c' splits "%s"|} splitter splitted in
-          (* limit being set to -1 is the same as not using the parameter *)
-          let split = XString.split ~limit:(-1) in
-          (split, name)
-      | Some limit ->
-          let name =
-            Printf.sprintf {|'%c' splits "%s" with limit %i|} splitter splitted
-              limit
-          in
-          let split = XString.split ~limit in
-          (split, name)
+  let test limit (splitter, splitted, expected) =
+    let split = XString.split ~limit in
+    let name =
+      Printf.sprintf {|'%c' splits "%s" with limit %i|} splitter splitted limit
     in
     test_list (split splitter) (name, splitted, expected)
   in
-  let specs_no_limit =
-    [
-      ('.', "...", [""; ""; ""; ""]); ('.', "foo.bar.baz", ["foo"; "bar"; "baz"])
-    ]
-  in
-  let tests_no_limit = List.map test specs_no_limit in
   let specs_limit =
     [
       (0, [('.', "...", ["..."]); ('.', "foo.bar.baz", ["foo.bar.baz"])])
@@ -82,12 +65,12 @@ let test_split =
     ; (4, [('.', "...", [""; ""; ""; ""])])
     ]
   in
-  let tests_limit =
+  let tests =
     List.concat_map
-      (fun (limit, spec) -> List.map (test ~limit) spec)
+      (fun (limit, spec) -> List.map (test limit) spec)
       specs_limit
   in
-  ("split", List.concat [tests_no_limit; tests_limit])
+  ("split", tests)
 
 let test_split_f =
   let specs =
diff --git a/ocaml/quicktest/quicktest_http.ml b/ocaml/quicktest/quicktest_http.ml
index 0320cf12ab3..09cccbc3e60 100644
--- a/ocaml/quicktest/quicktest_http.ml
+++ b/ocaml/quicktest/quicktest_http.ml
@@ -34,7 +34,7 @@ module Uds = struct
     with_channel_aux fd func
 
   let http_response_code d =
-    match Xapi_stdext_std.Xstringext.String.split ' ' d with
+    match Xapi_stdext_std.Xstringext.String.split_on_char ' ' d with
     | _ :: code :: _ ->
         int_of_string code
     | _ ->
diff --git a/ocaml/rrd2csv/src/rrd2csv.ml b/ocaml/rrd2csv/src/rrd2csv.ml
index 37e00f8148d..1cfadb61983 100644
--- a/ocaml/rrd2csv/src/rrd2csv.ml
+++ b/ocaml/rrd2csv/src/rrd2csv.ml
@@ -149,10 +149,10 @@ module Ds_selector = struct
 
   let of_string str =
     let open Rrd in
-    let splitted = Xstringext.String.split ',' str in
+    let splitted = String.split_on_char ',' str in
     match splitted with
     | without_trailing_comma :: _ -> (
-        let splitted = Xstringext.String.split ':' without_trailing_comma in
+        let splitted = String.split_on_char ':' without_trailing_comma in
         match splitted with
         | [cf; owner; uuid; metric] ->
             {
diff --git a/ocaml/xapi/authx.ml b/ocaml/xapi/authx.ml
index 87d85e40332..92f085648aa 100644
--- a/ocaml/xapi/authx.ml
+++ b/ocaml/xapi/authx.ml
@@ -65,7 +65,9 @@ module AuthX : Auth_signature.AUTH_MODULE = struct
             | [] ->
                 raise Not_found
             | line :: lines -> (
-                let recs = Xapi_stdext_std.Xstringext.String.split ':' line in
+                let recs =
+                  Xapi_stdext_std.Xstringext.String.split_on_char ':' line
+                in
                 let username = List.nth recs 0 in
                 let uid = List.nth recs 2 in
                 match fn username uid recs with
diff --git a/ocaml/xapi/config_file_sync.ml b/ocaml/xapi/config_file_sync.ml
index b765f1ceae6..c291ebcd841 100644
--- a/ocaml/xapi/config_file_sync.ml
+++ b/ocaml/xapi/config_file_sync.ml
@@ -58,7 +58,8 @@ let config_file_sync_handler (req : Http.Request.t) s _ =
   Xapi_http.with_context "Syncing dom0 config files over HTTP" req s
     (fun __context ->
       let uri =
-        String.split '/' req.Http.Request.path |> List.filter (fun x -> x <> "")
+        String.split_on_char '/' req.Http.Request.path
+        |> List.filter (fun x -> x <> "")
       in
       req.Http.Request.close <- true ;
       debug "sending headers" ;
diff --git a/ocaml/xapi/dbsync_slave.ml b/ocaml/xapi/dbsync_slave.ml
index ff325b7259e..bbd83451af8 100644
--- a/ocaml/xapi/dbsync_slave.ml
+++ b/ocaml/xapi/dbsync_slave.ml
@@ -75,9 +75,9 @@ let get_start_time () =
     match
       Unixext.string_of_file "/proc/stat"
       |> String.trim
-      |> String.split '\n'
+      |> String.split_on_char '\n'
       |> List.find (fun s -> String.starts_with ~prefix:"btime" s)
-      |> String.split ' '
+      |> String.split_on_char ' '
     with
     | _ :: btime :: _ ->
         let boot_time = Date.of_unix_time (float_of_string btime) in
@@ -111,7 +111,7 @@ let refresh_localhost_info ~__context info =
     | None ->
         []
     | Some {capabilities; _} ->
-        String.split ' ' capabilities
+        String.split_on_char ' ' capabilities
   in
   Db.Host.set_capabilities ~__context ~self:host ~value:caps ;
   Db.Host.set_address ~__context ~self:host ~value:(get_my_ip_addr ~__context) ;
diff --git a/ocaml/xapi/gpg.ml b/ocaml/xapi/gpg.ml
index 1dd5c8141c8..6589ea7c321 100644
--- a/ocaml/xapi/gpg.ml
+++ b/ocaml/xapi/gpg.ml
@@ -26,7 +26,7 @@ let gpg_binary_path = "/usr/bin/gpg"
 exception InvalidSignature
 
 let parse_gpg_status status_data =
-  let lines = String.split '\n' status_data in
+  let lines = String.split_on_char '\n' status_data in
   let status_contains substr =
     List.exists (fun s -> String.starts_with ~prefix:substr s) lines
   in
@@ -42,7 +42,7 @@ let parse_gpg_status status_data =
     let validsigline =
       List.find (fun s -> String.starts_with ~prefix:validsig s) lines
     in
-    match String.split ' ' validsigline with
+    match String.split_on_char ' ' validsigline with
     | _ :: _ :: fingerprint :: _ ->
         Some fingerprint
     | _ ->
diff --git a/ocaml/xapi/map_check.ml b/ocaml/xapi/map_check.ml
index 0cb2d97e37f..01de88d4290 100644
--- a/ocaml/xapi/map_check.ml
+++ b/ocaml/xapi/map_check.ml
@@ -104,7 +104,7 @@ let assert_value ~field ~key ~attr ~value =
   )
   | EnumSet range ->
       (* enumset is a comma-separated string *)
-      let vs = Xapi_stdext_std.Xstringext.String.split ',' value in
+      let vs = Xapi_stdext_std.Xstringext.String.split_on_char ',' value in
       List.fold_right
         (fun v acc ->
           match mem v range with
diff --git a/ocaml/xapi/nm.ml b/ocaml/xapi/nm.ml
index fa86a6f08e7..735bdbe98a8 100644
--- a/ocaml/xapi/nm.ml
+++ b/ocaml/xapi/nm.ml
@@ -470,7 +470,7 @@ let determine_static_routes net_rc =
   if List.mem_assoc "static-routes" net_rc.API.network_other_config then
     try
       let routes =
-        String.split ','
+        String.split_on_char ','
           (List.assoc "static-routes" net_rc.API.network_other_config)
       in
       List.map
diff --git a/ocaml/xapi/vhd_tool_wrapper.ml b/ocaml/xapi/vhd_tool_wrapper.ml
index f3f791fe251..049d8effdf2 100644
--- a/ocaml/xapi/vhd_tool_wrapper.ml
+++ b/ocaml/xapi/vhd_tool_wrapper.ml
@@ -125,7 +125,7 @@ let find_backend_device path =
     let link =
       Unix.readlink (Printf.sprintf "/sys/dev/block/%d:%d/device" major minor)
     in
-    match List.rev (String.split '/' link) with
+    match List.rev (String.split_on_char '/' link) with
     | id :: "xen" :: "devices" :: _
       when Astring.String.is_prefix ~affix:"vbd-" id ->
         let id = int_of_string (String.sub id 4 (String.length id - 4)) in
@@ -135,7 +135,7 @@ let find_backend_device path =
               xs.Xs.read (Printf.sprintf "device/vbd/%d/backend" id)
             in
             let params = xs.Xs.read (Printf.sprintf "%s/params" backend) in
-            match String.split '/' backend with
+            match String.split_on_char '/' backend with
             | "local" :: "domain" :: bedomid :: _ ->
                 if not (self = bedomid) then
                   Helpers.internal_error
diff --git a/ocaml/xapi/xapi_globs.ml b/ocaml/xapi/xapi_globs.ml
index 161273c83f9..1d3f3d2687f 100644
--- a/ocaml/xapi/xapi_globs.ml
+++ b/ocaml/xapi/xapi_globs.ml
@@ -1466,7 +1466,7 @@ let other_options =
       (fun s -> s)
       disable_dbsync_for
   ; ( "xenopsd-queues"
-    , Arg.String (fun x -> xenopsd_queues := String.split ',' x)
+    , Arg.String (fun x -> xenopsd_queues := String.split_on_char ',' x)
     , (fun () -> String.concat "," !xenopsd_queues)
     , "list of xenopsd instances to manage"
     )
@@ -1553,7 +1553,8 @@ let other_options =
   ; ( "nvidia_multi_vgpu_enabled_driver_versions"
     , Arg.String
         (fun x ->
-          nvidia_multi_vgpu_enabled_driver_versions := String.split ',' x
+          nvidia_multi_vgpu_enabled_driver_versions :=
+            String.split_on_char ',' x
         )
     , (fun () -> String.concat "," !nvidia_multi_vgpu_enabled_driver_versions)
     , "list of nvidia host driver versions with multiple vGPU supported.\n\
diff --git a/ocaml/xapi/xapi_pif.ml b/ocaml/xapi/xapi_pif.ml
index 881c51091fb..56bdb49e565 100644
--- a/ocaml/xapi/xapi_pif.ml
+++ b/ocaml/xapi/xapi_pif.ml
@@ -216,7 +216,9 @@ let refresh_all ~__context ~host =
     pifs
 
 let read_bridges_from_inventory () =
-  try String.split ' ' (Xapi_inventory.lookup Xapi_inventory._current_interfaces)
+  try
+    String.split_on_char ' '
+      (Xapi_inventory.lookup Xapi_inventory._current_interfaces)
   with _ -> []
 
 (* Ensure the PIF is not a bond slave. *)
@@ -716,7 +718,7 @@ let scan ~__context ~host =
         let output, _ =
           Forkhelpers.execute_command_get_output !Xapi_globs.non_managed_pifs []
         in
-        let dsplit = String.split '\n' output in
+        let dsplit = String.split_on_char '\n' output in
         match dsplit with
         | [] | [""] | "" :: "" :: _ ->
             debug "No boot from SAN interface found" ;
diff --git a/ocaml/xapi/xapi_pool_update.ml b/ocaml/xapi/xapi_pool_update.ml
index 6aa1ea0fd71..4338cfe37fe 100644
--- a/ocaml/xapi/xapi_pool_update.ml
+++ b/ocaml/xapi/xapi_pool_update.ml
@@ -376,7 +376,7 @@ let parse_update_info xml =
           | "" ->
               []
           | s ->
-              List.map guidance_from_string (String.split ',' s)
+              List.map guidance_from_string (String.split_on_char ',' s)
         with _ -> []
       in
       let enforce_homogeneity =
diff --git a/ocaml/xapi/xapi_xenops.ml b/ocaml/xapi/xapi_xenops.ml
index 0ea29ea4cf7..880fd58a54f 100644
--- a/ocaml/xapi/xapi_xenops.ml
+++ b/ocaml/xapi/xapi_xenops.ml
@@ -1182,8 +1182,8 @@ module MD = struct
       let affinity =
         try
           List.map
-            (fun x -> List.map int_of_string (String.split ',' x))
-            (String.split ';' (List.assoc "mask" vm.API.vM_VCPUs_params))
+            (fun x -> List.map int_of_string (String.split_on_char ',' x))
+            (String.split_on_char ';' (List.assoc "mask" vm.API.vM_VCPUs_params))
         with _ -> []
       in
       let localhost = Helpers.get_localhost ~__context in
@@ -1193,7 +1193,9 @@ module MD = struct
       let host_cpu_mask =
         try
           List.map int_of_string
-            (String.split ',' (List.assoc "mask" host_guest_VCPUs_params))
+            (String.split_on_char ','
+               (List.assoc "mask" host_guest_VCPUs_params)
+            )
         with _ -> []
       in
       let affinity =
@@ -1981,7 +1983,9 @@ let update_vm_internal ~__context ~id ~self ~previous ~info ~localhost =
               String.sub path (String.length dir)
                 (String.length path - String.length dir)
             in
-            match List.filter (fun x -> x <> "") (String.split '/' rest) with
+            match
+              List.filter (fun x -> x <> "") (String.split_on_char '/' rest)
+            with
             | x :: _ ->
                 Some x
             | _ ->
diff --git a/ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml b/ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml
index 6141090eae7..f60b825b16d 100644
--- a/ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml
+++ b/ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml
@@ -437,7 +437,7 @@ let exec_tap_ctl_list () : ((string * string) * int) list =
 let minor_of_tapdev_unsafe tapdev =
   int_of_string
     (Unixext.file_lines_fold
-       (fun acc l -> acc ^ List.nth (Xstringext.String.split ':' l) 1)
+       (fun acc l -> acc ^ List.nth (Xstringext.String.split_on_char ':' l) 1)
        ""
        ("/sys/block/" ^ tapdev ^ "/dev")
     )
diff --git a/ocaml/xcp-rrdd/bin/rrdp-squeezed/rrdp_squeezed.ml b/ocaml/xcp-rrdd/bin/rrdp-squeezed/rrdp_squeezed.ml
index df49dca259f..ec5b783f3da 100644
--- a/ocaml/xcp-rrdd/bin/rrdp-squeezed/rrdp_squeezed.ml
+++ b/ocaml/xcp-rrdd/bin/rrdp-squeezed/rrdp_squeezed.ml
@@ -81,7 +81,9 @@ module MemoryActions = struct
             path domid ;
           current_memory_values := IntMap.remove domid !current_memory_values
     in
-    match List.filter (fun x -> x <> "") (Xstringext.String.split '/' path) with
+    match
+      List.filter (fun x -> x <> "") (Xstringext.String.split_on_char '/' path)
+    with
     | ["local"; "domain"; domid; "memory"; "dynamic-max"] ->
         read_new_value domid current_dynamic_max_values
     | ["local"; "domain"; domid; "memory"; "dynamic-min"] ->
diff --git a/ocaml/xe-cli/newcli.ml b/ocaml/xe-cli/newcli.ml
index 60ecce2a47d..c027a9b2e41 100644
--- a/ocaml/xe-cli/newcli.ml
+++ b/ocaml/xe-cli/newcli.ml
@@ -389,7 +389,7 @@ let with_open_channels f =
   match result with Ok r -> r | Error e -> raise e
 
 let http_response_code x =
-  match String.split ' ' x with
+  match String.split_on_char ' ' x with
   | _ :: code :: _ ->
       int_of_string code
   | _ ->

From 8ae7840dce051405fffeade39078ad013922e2d6 Mon Sep 17 00:00:00 2001
From: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Date: Mon, 20 May 2024 16:26:56 +0100
Subject: [PATCH 2/8] xapi-stdext-std: Do not include String functions in
 XStringext

Also remove all indiscriminate opens against it

Signed-off-by: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Signed-off-by: Pau Ruiz Safont <pau.safont@vates.tech>
---
 ocaml/database/parse_db_conf.ml               |  1 -
 ocaml/database/redo_log.ml                    |  1 -
 ocaml/doc/dune                                |  3 +-
 ocaml/doc/jsapi.ml                            |  1 -
 ocaml/idl/ocaml_backend/gen_rbac.ml           |  5 ++--
 .../lib/xapi-stdext-std/xstringext.ml         | 21 +++----------
 .../lib/xapi-stdext-std/xstringext.mli        |  2 --
 ocaml/quicktest/quicktest_http.ml             |  2 +-
 ocaml/xapi/authx.ml                           |  9 ++----
 ocaml/xapi/config_file_sync.ml                |  1 -
 ocaml/xapi/dbsync_slave.ml                    |  1 -
 ocaml/xapi/extauth_plugin_ADpbis.ml           | 30 ++++++++++---------
 ocaml/xapi/extauth_plugin_ADwinbind.ml        |  1 -
 ocaml/xapi/fileserver.ml                      |  4 +--
 ocaml/xapi/gpg.ml                             |  1 -
 ocaml/xapi/import.ml                          |  1 -
 ocaml/xapi/map_check.ml                       |  2 +-
 ocaml/xapi/nm.ml                              |  4 +--
 ocaml/xapi/sm.ml                              |  1 -
 ocaml/xapi/storage_mux.ml                     |  4 +--
 ocaml/xapi/vgpuops.ml                         |  1 -
 ocaml/xapi/vhd_tool_wrapper.ml                |  1 -
 ocaml/xapi/wlb_reports.ml                     |  1 -
 ocaml/xapi/workload_balancing.ml              |  5 ++--
 ocaml/xapi/xapi_dr_task.ml                    |  1 -
 ocaml/xapi/xapi_globs.ml                      |  4 +--
 ocaml/xapi/xapi_network.ml                    |  1 -
 ocaml/xapi/xapi_pif.ml                        |  6 ++--
 ocaml/xapi/xapi_pool.ml                       |  1 -
 ocaml/xapi/xapi_pool_update.ml                |  7 +++--
 ocaml/xapi/xapi_secret.ml                     |  2 --
 ocaml/xapi/xapi_vbd_helpers.ml                |  1 -
 ocaml/xapi/xapi_vif_helpers.ml                |  2 --
 ocaml/xapi/xapi_vusb_helpers.ml               |  2 --
 ocaml/xapi/xapi_xenops.ml                     |  4 +--
 ocaml/xapi/xha_interface.ml                   |  5 ++--
 ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml |  2 +-
 .../bin/rrdp-squeezed/rrdp_squeezed.ml        |  5 +---
 ocaml/xe-cli/newcli.ml                        |  4 +--
 39 files changed, 54 insertions(+), 96 deletions(-)

diff --git a/ocaml/database/parse_db_conf.ml b/ocaml/database/parse_db_conf.ml
index 76deca97e42..d1c7482c080 100644
--- a/ocaml/database/parse_db_conf.ml
+++ b/ocaml/database/parse_db_conf.ml
@@ -13,7 +13,6 @@
  *)
 (* !!! This needs to be moved out of xapi and into the database directory; probably being merged with db_connections !!! *)
 
-open Xapi_stdext_std.Xstringext
 open Xapi_stdext_unix
 
 module D = Debug.Make (struct let name = "parse_db_conf" end)
diff --git a/ocaml/database/redo_log.ml b/ocaml/database/redo_log.ml
index 8c2c95928d7..42175580f83 100644
--- a/ocaml/database/redo_log.ml
+++ b/ocaml/database/redo_log.ml
@@ -12,7 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 open Xapi_stdext_pervasives.Pervasiveext
-open Xapi_stdext_std.Xstringext
 open Xapi_stdext_unix
 
 let with_lock = Xapi_stdext_threads.Threadext.Mutex.execute
diff --git a/ocaml/doc/dune b/ocaml/doc/dune
index 061ba778232..618de9e30fb 100644
--- a/ocaml/doc/dune
+++ b/ocaml/doc/dune
@@ -1,7 +1,7 @@
 (executable
   (modes exe)
   (name jsapi)
-  (libraries    
+  (libraries
     mustache
     rpclib.core
     rpclib.json
@@ -10,7 +10,6 @@
     xapi-consts
     xapi-datamodel
     xapi-stdext-pervasives
-    xapi-stdext-std
     xapi-stdext-unix
   )
   (preprocess (pps ppx_deriving_rpc))
diff --git a/ocaml/doc/jsapi.ml b/ocaml/doc/jsapi.ml
index fa891e57743..1fef7fabf00 100644
--- a/ocaml/doc/jsapi.ml
+++ b/ocaml/doc/jsapi.ml
@@ -12,7 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 
-open Xapi_stdext_std.Xstringext
 open Xapi_stdext_pervasives.Pervasiveext
 module Unixext = Xapi_stdext_unix.Unixext
 open Datamodel_types
diff --git a/ocaml/idl/ocaml_backend/gen_rbac.ml b/ocaml/idl/ocaml_backend/gen_rbac.ml
index 7914dba96dd..6934d691a3f 100644
--- a/ocaml/idl/ocaml_backend/gen_rbac.ml
+++ b/ocaml/idl/ocaml_backend/gen_rbac.ml
@@ -70,11 +70,10 @@ let role_uuid name = Option.get (hash2uuid name)
 let permission_description = "A basic permission"
 
 let permission_name wire_name =
-  let open Xapi_stdext_std in
   let s1 = replace_char (Printf.sprintf "permission_%s" wire_name) '.' '_' in
   let s2 = replace_char s1 '/' '_' in
-  let s3 = Xstringext.String.replace "*" "WILDCHAR" s2 in
-  Xstringext.String.replace ":" "_" s3
+  let s3 = Xapi_stdext_std.Xstringext.String.replace "*" "WILDCHAR" s2 in
+  replace_char s3 ':' '_'
 
 let permission_index = ref 0
 
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
index 6c759498def..0512cc35dc5 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
@@ -12,29 +12,27 @@
  * GNU Lesser General Public License for more details.
  *)
 module String = struct
-  include String
-
   let of_char c = String.make 1 c
 
   let rev_map f string =
-    let n = length string in
+    let n = String.length string in
     String.init n (fun i -> f string.[n - i - 1])
 
   let rev_iter f string =
-    for i = length string - 1 downto 0 do
+    for i = String.length string - 1 downto 0 do
       f string.[i]
     done
 
   let fold_left f accu string =
     let accu = ref accu in
-    for i = 0 to length string - 1 do
+    for i = 0 to String.length string - 1 do
       accu := f !accu string.[i]
     done ;
     !accu
 
   let fold_right f string accu =
     let accu = ref accu in
-    for i = length string - 1 downto 0 do
+    for i = String.length string - 1 downto 0 do
       accu := f string.[i] !accu
     done ;
     !accu
@@ -65,17 +63,6 @@ module String = struct
     |> List.of_seq
     |> List.rev
 
-  let index_opt s c =
-    let rec loop i =
-      if String.length s = i then
-        None
-      else if s.[i] = c then
-        Some i
-      else
-        loop (i + 1)
-    in
-    loop 0
-
   let sub_to_end s start =
     let length = String.length s in
     String.sub s start (length - start)
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
index d68e3f524f8..a890537c1de 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
@@ -12,8 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 module String : sig
-  include module type of String
-
   val of_char : char -> string
 
   val rev_map : (char -> char) -> string -> string
diff --git a/ocaml/quicktest/quicktest_http.ml b/ocaml/quicktest/quicktest_http.ml
index 09cccbc3e60..86f9660e7ce 100644
--- a/ocaml/quicktest/quicktest_http.ml
+++ b/ocaml/quicktest/quicktest_http.ml
@@ -34,7 +34,7 @@ module Uds = struct
     with_channel_aux fd func
 
   let http_response_code d =
-    match Xapi_stdext_std.Xstringext.String.split_on_char ' ' d with
+    match String.split_on_char ' ' d with
     | _ :: code :: _ ->
         int_of_string code
     | _ ->
diff --git a/ocaml/xapi/authx.ml b/ocaml/xapi/authx.ml
index 92f085648aa..7236c793fb4 100644
--- a/ocaml/xapi/authx.ml
+++ b/ocaml/xapi/authx.ml
@@ -65,9 +65,7 @@ module AuthX : Auth_signature.AUTH_MODULE = struct
             | [] ->
                 raise Not_found
             | line :: lines -> (
-                let recs =
-                  Xapi_stdext_std.Xstringext.String.split_on_char ':' line
-                in
+                let recs = String.split_on_char ':' line in
                 let username = List.nth recs 0 in
                 let uid = List.nth recs 2 in
                 match fn username uid recs with
@@ -293,9 +291,8 @@ module AuthX : Auth_signature.AUTH_MODULE = struct
     | _ ->
         raise Not_found
 
-  (*
-	In addition, there are some event hooks that auth modules implement as follows:
-*)
+  (* In addition, there are some event hooks that auth modules implement as
+     follows: *)
 
   (* unit on_enable(((string*string) list) config_params)
 
diff --git a/ocaml/xapi/config_file_sync.ml b/ocaml/xapi/config_file_sync.ml
index c291ebcd841..cf877745290 100644
--- a/ocaml/xapi/config_file_sync.ml
+++ b/ocaml/xapi/config_file_sync.ml
@@ -15,7 +15,6 @@
 module D = Debug.Make (struct let name = "config_file_sync" end)
 
 open D
-open Xapi_stdext_std.Xstringext
 
 let superuser = "root"
 
diff --git a/ocaml/xapi/dbsync_slave.ml b/ocaml/xapi/dbsync_slave.ml
index bbd83451af8..ea5dddf8f82 100644
--- a/ocaml/xapi/dbsync_slave.ml
+++ b/ocaml/xapi/dbsync_slave.ml
@@ -17,7 +17,6 @@
 *)
 
 module Rrdd = Rrd_client.Client
-open Xapi_stdext_std.Xstringext
 module Unixext = Xapi_stdext_unix.Unixext
 module Date = Clock.Date
 open Create_misc
diff --git a/ocaml/xapi/extauth_plugin_ADpbis.ml b/ocaml/xapi/extauth_plugin_ADpbis.ml
index ea2dedfccc6..6c532c8eb70 100644
--- a/ocaml/xapi/extauth_plugin_ADpbis.ml
+++ b/ocaml/xapi/extauth_plugin_ADpbis.ml
@@ -18,7 +18,7 @@
 module D = Debug.Make (struct let name = "extauth_plugin_ADpbis" end)
 
 open D
-open Xapi_stdext_std.Xstringext
+module Stringext = Xapi_stdext_std.Xstringext.String
 
 let ( let@ ) = ( @@ )
 
@@ -106,7 +106,7 @@ let match_error_tag (lines : string list) =
   in
   let split_to_words str =
     let seps = ['('; ')'; ' '; '\t'; '.'] in
-    String.split_f (fun s -> List.exists (fun sep -> sep = s) seps) str
+    Stringext.split_f (fun s -> List.exists (fun sep -> sep = s) seps) str
   in
   let rec has_err lines err_pattern =
     match lines with
@@ -131,9 +131,9 @@ let match_error_tag (lines : string list) =
 let extract_sid_from_group_list group_list =
   List.map
     (fun (_, v) ->
-      let v = String.replace ")" "" v in
-      let v = String.replace "sid =" "|" v in
-      let vs = String.split_f (fun c -> c = '|') v in
+      let v = Stringext.replace ")" "" v in
+      let v = Stringext.replace "sid =" "|" v in
+      let vs = Stringext.split_f (fun c -> c = '|') v in
       let sid = String.trim (List.nth vs 1) in
       debug "extract_sid_from_group_list get sid=[%s]" sid ;
       sid
@@ -166,7 +166,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
     Locking_helpers.Named_mutex.create "IS_SERVER_AVAILABLE"
 
   let splitlines s =
-    String.split_f (fun c -> c = '\n') (String.replace "#012" "\n" s)
+    Stringext.split_f (fun c -> c = '\n') (Stringext.replace "#012" "\n" s)
 
   let pbis_common_with_password (password : string) (pbis_cmd : string)
       (pbis_args : string list) =
@@ -238,7 +238,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
       pbis_cmd ^ " " ^ List.fold_left (fun p pp -> p ^ " " ^ pp) " " pbis_args
     in
     let debug_cmd =
-      if String.has_substr debug_cmd "--password" then
+      if Stringext.has_substr debug_cmd "--password" then
         "(omitted for security)"
       else
         debug_cmd
@@ -348,9 +348,11 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
         if !exited_code <> 0 then (
           error "execute '%s': exit_code=[%d] output=[%s]" debug_cmd
             !exited_code
-            (String.replace "\n" ";" !output) ;
+            (Stringext.replace "\n" ";" !output) ;
           let split_to_words s =
-            String.split_f (fun c -> c = '(' || c = ')' || c = '.' || c = ' ') s
+            Stringext.split_f
+              (fun c -> c = '(' || c = ')' || c = '.' || c = ' ')
+              s
           in
           let revlines =
             List.rev
@@ -416,7 +418,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
           List.filter (fun l -> String.length l > 0) (splitlines !output)
         in
         let parse_line (acc, currkey) line =
-          let slices = String.split ~limit:2 ':' line in
+          let slices = Stringext.split ~limit:2 ':' line in
           debug "parse %s: currkey=[%s] line=[%s]" debug_cmd currkey line ;
           if List.length slices > 1 then (
             let key = String.trim (List.hd slices) in
@@ -619,7 +621,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
     (* first, we try to authenticated user against our external user database *)
     (* pbis_common will raise an Auth_failure if external authentication fails *)
     let domain, user =
-      match String.split_f (fun c -> c = '\\') username with
+      match Stringext.split_f (fun c -> c = '\\') username with
       | [domain; user] ->
           (domain, user)
       | [user] ->
@@ -976,7 +978,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
             | "" ->
                 []
             | disabled_modules_string ->
-                String.split_f (fun c -> c = ',') disabled_modules_string
+                Stringext.split_f (fun c -> c = ',') disabled_modules_string
           with Not_found -> []
         in
         let disabled_module_params =
@@ -1113,8 +1115,8 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
         in
         debug "execute %s: stdout=[%s],stderr=[%s]"
           pbis_force_domain_leave_script
-          (String.replace "\n" ";" output)
-          (String.replace "\n" ";" stderr)
+          (Stringext.replace "\n" ";" output)
+          (Stringext.replace "\n" ";" stderr)
       with e ->
         debug "exception executing %s: %s" pbis_force_domain_leave_script
           (ExnHelper.string_of_exn e)
diff --git a/ocaml/xapi/extauth_plugin_ADwinbind.ml b/ocaml/xapi/extauth_plugin_ADwinbind.ml
index 837dc429ca2..86d0e8c25b2 100644
--- a/ocaml/xapi/extauth_plugin_ADwinbind.ml
+++ b/ocaml/xapi/extauth_plugin_ADwinbind.ml
@@ -20,7 +20,6 @@ module D = Debug.Make (struct
 end)
 
 open D
-open Xapi_stdext_std.Xstringext
 open Auth_signature
 module Scheduler = Xapi_stdext_threads_scheduler.Scheduler
 
diff --git a/ocaml/xapi/fileserver.ml b/ocaml/xapi/fileserver.ml
index 9820a55d5ce..7c29441df35 100644
--- a/ocaml/xapi/fileserver.ml
+++ b/ocaml/xapi/fileserver.ml
@@ -16,14 +16,14 @@
  *)
 
 open Http
-open Xapi_stdext_std.Xstringext
+module Xstringext = Xapi_stdext_std.Xstringext.String
 
 module D = Debug.Make (struct let name = "fileserver" end)
 
 open D
 
 let escape uri =
-  String.escaped
+  Xstringext.escaped
     ~rules:
       [
         ('<', "&lt;")
diff --git a/ocaml/xapi/gpg.ml b/ocaml/xapi/gpg.ml
index 6589ea7c321..def89c7890b 100644
--- a/ocaml/xapi/gpg.ml
+++ b/ocaml/xapi/gpg.ml
@@ -13,7 +13,6 @@
  *)
 (** Wrapper around gpg *)
 
-open Xapi_stdext_std.Xstringext
 open Xapi_stdext_pervasives.Pervasiveext
 module Unixext = Xapi_stdext_unix.Unixext
 
diff --git a/ocaml/xapi/import.ml b/ocaml/xapi/import.ml
index 04306cff5f6..c854ed1807d 100644
--- a/ocaml/xapi/import.ml
+++ b/ocaml/xapi/import.ml
@@ -19,7 +19,6 @@ module D = Debug.Make (struct let name = "import" end)
 
 open D
 module Listext = Xapi_stdext_std.Listext
-module Xstringext = Xapi_stdext_std.Xstringext
 module Unixext = Xapi_stdext_unix.Unixext
 open Http
 open Importexport
diff --git a/ocaml/xapi/map_check.ml b/ocaml/xapi/map_check.ml
index 01de88d4290..503ccd2ce8a 100644
--- a/ocaml/xapi/map_check.ml
+++ b/ocaml/xapi/map_check.ml
@@ -104,7 +104,7 @@ let assert_value ~field ~key ~attr ~value =
   )
   | EnumSet range ->
       (* enumset is a comma-separated string *)
-      let vs = Xapi_stdext_std.Xstringext.String.split_on_char ',' value in
+      let vs = String.split_on_char ',' value in
       List.fold_right
         (fun v acc ->
           match mem v range with
diff --git a/ocaml/xapi/nm.ml b/ocaml/xapi/nm.ml
index 735bdbe98a8..4df9bf233f9 100644
--- a/ocaml/xapi/nm.ml
+++ b/ocaml/xapi/nm.ml
@@ -14,7 +14,7 @@
 module D = Debug.Make (struct let name = "nm" end)
 
 open D
-open Xapi_stdext_std.Xstringext
+module Stringext = Xapi_stdext_std.Xstringext.String
 module Listext = Xapi_stdext_std.Listext.List
 open Xapi_database.Db_filter_types
 open Network
@@ -216,7 +216,7 @@ let create_bond ~__context bond mtu persistent =
         List.filter_map
           (fun (k, v) ->
             if String.starts_with ~prefix:"bond-" k then
-              Some (String.sub_to_end k 5, v)
+              Some (Stringext.sub_to_end k 5, v)
             else
               None
           )
diff --git a/ocaml/xapi/sm.ml b/ocaml/xapi/sm.ml
index 1d198cf3f98..532f6fb44b1 100644
--- a/ocaml/xapi/sm.ml
+++ b/ocaml/xapi/sm.ml
@@ -15,7 +15,6 @@
  * @group Storage
 *)
 
-open Xapi_stdext_std.Xstringext
 open Smint
 open Printf
 
diff --git a/ocaml/xapi/storage_mux.ml b/ocaml/xapi/storage_mux.ml
index 0427f76ca54..ac8b0680f43 100644
--- a/ocaml/xapi/storage_mux.ml
+++ b/ocaml/xapi/storage_mux.ml
@@ -780,9 +780,9 @@ module Mux = struct
     (* Assume it has either the format:
        SR/VDI -- for a particular SR and VDI
        content_id -- for a particular content *)
-    let open Xapi_stdext_std.Xstringext in
+    let split = Xapi_stdext_std.Xstringext.String.split in
     with_dbg ~name:"get_by_name" ~dbg @@ fun di ->
-    match List.filter (fun x -> x <> "") (String.split ~limit:2 '/' name) with
+    match List.filter (fun x -> x <> "") (split ~limit:2 '/' name) with
     | [sr; name] ->
         let sr = Storage_interface.Sr.of_string sr in
         let module C = StorageAPI (Idl.Exn.GenClient (struct
diff --git a/ocaml/xapi/vgpuops.ml b/ocaml/xapi/vgpuops.ml
index e47b0896ab3..248ec2839a1 100644
--- a/ocaml/xapi/vgpuops.ml
+++ b/ocaml/xapi/vgpuops.ml
@@ -15,7 +15,6 @@ module D = Debug.Make (struct let name = "vgpuops" end)
 
 open D
 module Listext = Xapi_stdext_std.Listext.List
-open Xapi_stdext_std.Xstringext
 
 type vgpu_t = {
     vgpu_ref: API.ref_VGPU
diff --git a/ocaml/xapi/vhd_tool_wrapper.ml b/ocaml/xapi/vhd_tool_wrapper.ml
index 049d8effdf2..e8c051c0ef7 100644
--- a/ocaml/xapi/vhd_tool_wrapper.ml
+++ b/ocaml/xapi/vhd_tool_wrapper.ml
@@ -18,7 +18,6 @@
 module D = Debug.Make (struct let name = "vhd_tool_wrapper" end)
 
 open D
-open Xapi_stdext_std.Xstringext
 
 (* .vhds on XenServer are sometimes found via /dev/mapper *)
 let vhd_search_path = "/dev/mapper:."
diff --git a/ocaml/xapi/wlb_reports.ml b/ocaml/xapi/wlb_reports.ml
index e466bf959f5..8de0e80b298 100644
--- a/ocaml/xapi/wlb_reports.ml
+++ b/ocaml/xapi/wlb_reports.ml
@@ -92,7 +92,6 @@
 
 open Printf
 open Http
-open Xapi_stdext_std.Xstringext
 
 module D = Debug.Make (struct let name = "wlb_reports" end)
 
diff --git a/ocaml/xapi/workload_balancing.ml b/ocaml/xapi/workload_balancing.ml
index 7108032dbf7..47124c1f355 100644
--- a/ocaml/xapi/workload_balancing.ml
+++ b/ocaml/xapi/workload_balancing.ml
@@ -16,7 +16,6 @@
 *)
 
 open Printf
-open Xapi_stdext_std.Xstringext
 
 module D = Debug.Make (struct let name = "workload_balancing" end)
 
@@ -87,7 +86,9 @@ let split_host_port url =
       in
       (host, int_of_string port)
     ) else
-      match String.split_f (fun a -> a = ':') url with
+      match
+        Xapi_stdext_std.Xstringext.String.split_f (fun a -> a = ':') url
+      with
       | [host; port] ->
           (host, int_of_string port)
       | _ ->
diff --git a/ocaml/xapi/xapi_dr_task.ml b/ocaml/xapi/xapi_dr_task.ml
index de7d15e0523..56626ea1368 100644
--- a/ocaml/xapi/xapi_dr_task.ml
+++ b/ocaml/xapi/xapi_dr_task.ml
@@ -13,7 +13,6 @@
  *)
 
 open Client
-open Xapi_stdext_std.Xstringext
 
 module D = Debug.Make (struct let name = "xapi_dr_task" end)
 
diff --git a/ocaml/xapi/xapi_globs.ml b/ocaml/xapi/xapi_globs.ml
index 1d3f3d2687f..38700758b0b 100644
--- a/ocaml/xapi/xapi_globs.ml
+++ b/ocaml/xapi/xapi_globs.ml
@@ -14,8 +14,6 @@
 
 (** A central location for settings related to xapi *)
 
-module String_plain = String (* For when we don't want the Xstringext version *)
-open Xapi_stdext_std.Xstringext
 module StringSet = Set.Make (String)
 
 module D = Debug.Make (struct let name = "xapi_globs" end)
@@ -1370,7 +1368,7 @@ let gen_list_option name desc of_string string_of opt =
   let parse s =
     opt := [] ;
     try
-      String.split_f String.isspace s
+      Xapi_stdext_std.Xstringext.String.(split_f isspace s)
       |> List.iter (fun x -> opt := of_string x :: !opt)
     with e ->
       D.error "Unable to parse %s=%s (expected space-separated list) error: %s"
diff --git a/ocaml/xapi/xapi_network.ml b/ocaml/xapi/xapi_network.ml
index 73a59fd698c..dd937ad5784 100644
--- a/ocaml/xapi/xapi_network.ml
+++ b/ocaml/xapi/xapi_network.ml
@@ -14,7 +14,6 @@
 let with_lock = Xapi_stdext_threads.Threadext.Mutex.execute
 
 open Client
-open Xapi_stdext_std.Xstringext
 
 module D = Debug.Make (struct let name = "xapi_network" end)
 
diff --git a/ocaml/xapi/xapi_pif.ml b/ocaml/xapi/xapi_pif.ml
index 56bdb49e565..0e730bda514 100644
--- a/ocaml/xapi/xapi_pif.ml
+++ b/ocaml/xapi/xapi_pif.ml
@@ -19,7 +19,7 @@ module L = Debug.Make (struct let name = "license" end)
 
 open Xapi_database.Db_filter_types
 module Listext = Xapi_stdext_std.Listext.List
-open Xapi_stdext_std.Xstringext
+module Stringext = Xapi_stdext_std.Xstringext.String
 module Date = Clock.Date
 open Network
 
@@ -724,9 +724,9 @@ let scan ~__context ~host =
             debug "No boot from SAN interface found" ;
             ([], [])
         | m :: u :: _ ->
-            (String.split_f String.isspace m, String.split_f String.isspace u)
+            Stringext.(split_f isspace m, split_f isspace u)
         | m :: _ ->
-            (String.split_f String.isspace m, [])
+            Stringext.(split_f isspace m, [])
       with e ->
         warn "Error when executing script %s: %s; ignoring"
           !Xapi_globs.non_managed_pifs
diff --git a/ocaml/xapi/xapi_pool.ml b/ocaml/xapi/xapi_pool.ml
index 752d822135f..89e656ec8e2 100644
--- a/ocaml/xapi/xapi_pool.ml
+++ b/ocaml/xapi/xapi_pool.ml
@@ -16,7 +16,6 @@ open Client
 module Date = Clock.Date
 module Listext = Xapi_stdext_std.Listext
 module Unixext = Xapi_stdext_unix.Unixext
-module Xstringext = Xapi_stdext_std.Xstringext
 
 module Pkgs = (val Pkg_mgr.get_pkg_mgr)
 
diff --git a/ocaml/xapi/xapi_pool_update.ml b/ocaml/xapi/xapi_pool_update.ml
index 4338cfe37fe..a0b0534628a 100644
--- a/ocaml/xapi/xapi_pool_update.ml
+++ b/ocaml/xapi/xapi_pool_update.ml
@@ -12,7 +12,7 @@
  * GNU Lesser General Public License for more details.
  *)
 
-open Xapi_stdext_std.Xstringext
+module Stringext = Xapi_stdext_std.Xstringext.String
 module Unixext = Xapi_stdext_unix.Unixext
 open Http
 open Helpers
@@ -770,9 +770,10 @@ let resync_host ~__context ~host =
 let path_and_host_from_uri uri =
   (* remove any dodgy use of "." or ".." NB we don't prevent the use of symlinks *)
   let host_and_path =
-    String.sub_to_end uri (String.length Constants.get_pool_update_download_uri)
+    Stringext.sub_to_end uri
+      (String.length Constants.get_pool_update_download_uri)
   in
-  match String.split ~limit:2 '/' host_and_path with
+  match Stringext.split ~limit:2 '/' host_and_path with
   | [host; untrusted_path] ->
       let resolved_path =
         untrusted_path
diff --git a/ocaml/xapi/xapi_secret.ml b/ocaml/xapi/xapi_secret.ml
index 57492840ead..9ca6eb88276 100644
--- a/ocaml/xapi/xapi_secret.ml
+++ b/ocaml/xapi/xapi_secret.ml
@@ -15,8 +15,6 @@
  * @group XenAPI functions
 *)
 
-open Xapi_stdext_std.Xstringext
-
 module D = Debug.Make (struct let name = "xapi_secret" end)
 
 open D
diff --git a/ocaml/xapi/xapi_vbd_helpers.ml b/ocaml/xapi/xapi_vbd_helpers.ml
index 07d6b012da2..7fe8f32aa50 100644
--- a/ocaml/xapi/xapi_vbd_helpers.ml
+++ b/ocaml/xapi/xapi_vbd_helpers.ml
@@ -15,7 +15,6 @@
  * @group Storage
 *)
 
-open Xapi_stdext_std.Xstringext
 module Listext = Xapi_stdext_std.Listext
 module Date = Clock.Date
 
diff --git a/ocaml/xapi/xapi_vif_helpers.ml b/ocaml/xapi/xapi_vif_helpers.ml
index 37de1b77770..9bc87f3a553 100644
--- a/ocaml/xapi/xapi_vif_helpers.ml
+++ b/ocaml/xapi/xapi_vif_helpers.ml
@@ -12,8 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 
-open Xapi_stdext_std.Xstringext
-
 module D = Debug.Make (struct let name = "xapi_vif_helpers" end)
 
 open D
diff --git a/ocaml/xapi/xapi_vusb_helpers.ml b/ocaml/xapi/xapi_vusb_helpers.ml
index 19298735a06..0cf59fa5167 100644
--- a/ocaml/xapi/xapi_vusb_helpers.ml
+++ b/ocaml/xapi/xapi_vusb_helpers.ml
@@ -12,8 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 
-open Xapi_stdext_std.Xstringext
-
 module D = Debug.Make (struct let name = "xapi_vusb_helpers" end)
 
 (**************************************************************************************)
diff --git a/ocaml/xapi/xapi_xenops.ml b/ocaml/xapi/xapi_xenops.ml
index 880fd58a54f..a39a9983c86 100644
--- a/ocaml/xapi/xapi_xenops.ml
+++ b/ocaml/xapi/xapi_xenops.ml
@@ -17,9 +17,9 @@ module D = Debug.Make (struct let name = "xenops" end)
 open D
 module StringSet = Set.Make (String)
 open Network
-open Xapi_stdext_std.Xstringext
 module Date = Clock.Date
 module Listext = Xapi_stdext_std.Listext.List
+module Stringext = Xapi_stdext_std.Xstringext.String
 
 let with_lock = Xapi_stdext_threads.Threadext.Mutex.execute
 
@@ -129,7 +129,7 @@ let disk_of_vdi ~__context ~self =
 
 let vdi_of_disk ~__context x =
   let@ __context = Context.with_tracing ~__context __FUNCTION__ in
-  match String.split ~limit:2 '/' x with
+  match Stringext.split ~limit:2 '/' x with
   | [sr_uuid; location] -> (
       let open Xapi_database.Db_filter_types in
       let sr = Db.SR.get_by_uuid ~__context ~uuid:sr_uuid in
diff --git a/ocaml/xapi/xha_interface.ml b/ocaml/xapi/xha_interface.ml
index 82ac381519d..a42107a63a6 100644
--- a/ocaml/xapi/xha_interface.ml
+++ b/ocaml/xapi/xha_interface.ml
@@ -12,7 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 open API
-open Xapi_stdext_std.Xstringext
 
 let hashtbl_of_list xs =
   let tbl = Hashtbl.create (List.length xs) in
@@ -350,7 +349,9 @@ module LiveSetInformation = struct
             | Some u ->
                 u
           in
-          let set f x = List.map f (String.split_f String.isspace x) in
+          let set f x =
+            List.map f Xapi_stdext_std.Xstringext.String.(split_f isspace x)
+          in
           Some
             {
               id= uuid (find "HostID")
diff --git a/ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml b/ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml
index f60b825b16d..cad87fc6614 100644
--- a/ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml
+++ b/ocaml/xcp-rrdd/bin/rrdp-iostat/rrdp_iostat.ml
@@ -437,7 +437,7 @@ let exec_tap_ctl_list () : ((string * string) * int) list =
 let minor_of_tapdev_unsafe tapdev =
   int_of_string
     (Unixext.file_lines_fold
-       (fun acc l -> acc ^ List.nth (Xstringext.String.split_on_char ':' l) 1)
+       (fun acc l -> acc ^ List.nth (String.split_on_char ':' l) 1)
        ""
        ("/sys/block/" ^ tapdev ^ "/dev")
     )
diff --git a/ocaml/xcp-rrdd/bin/rrdp-squeezed/rrdp_squeezed.ml b/ocaml/xcp-rrdd/bin/rrdp-squeezed/rrdp_squeezed.ml
index ec5b783f3da..55a190b8988 100644
--- a/ocaml/xcp-rrdd/bin/rrdp-squeezed/rrdp_squeezed.ml
+++ b/ocaml/xcp-rrdd/bin/rrdp-squeezed/rrdp_squeezed.ml
@@ -12,7 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 
-open Xapi_stdext_std
 open Rrdd_plugin
 
 module Process = Process (struct let name = "xcp-rrdd-squeezed" end)
@@ -81,9 +80,7 @@ module MemoryActions = struct
             path domid ;
           current_memory_values := IntMap.remove domid !current_memory_values
     in
-    match
-      List.filter (fun x -> x <> "") (Xstringext.String.split_on_char '/' path)
-    with
+    match List.filter (fun x -> x <> "") (String.split_on_char '/' path) with
     | ["local"; "domain"; domid; "memory"; "dynamic-max"] ->
         read_new_value domid current_dynamic_max_values
     | ["local"; "domain"; domid; "memory"; "dynamic-min"] ->
diff --git a/ocaml/xe-cli/newcli.ml b/ocaml/xe-cli/newcli.ml
index c027a9b2e41..e8b7179e372 100644
--- a/ocaml/xe-cli/newcli.ml
+++ b/ocaml/xe-cli/newcli.ml
@@ -13,7 +13,7 @@
  *)
 (* New cli talking to the in-server cli interface *)
 
-open Xapi_stdext_std.Xstringext
+module Stringext = Xapi_stdext_std.Xstringext.String
 open Xapi_stdext_pervasives
 open Cli_protocol
 
@@ -306,7 +306,7 @@ let parse_args =
             || (extra_args.[!i] = ',' && extra_args.[!i - 1] <> '\\')
           then (
           let seg = String.sub extra_args !pos (!i - !pos) in
-          l := String.filter_chars seg (( <> ) '\\') :: !l ;
+          l := Stringext.filter_chars seg (( <> ) '\\') :: !l ;
           incr i ;
           pos := !i
         ) else

From 81fb38651ebd47059a00c0a04835876419c75bac Mon Sep 17 00:00:00 2001
From: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Date: Mon, 20 May 2024 16:37:30 +0100
Subject: [PATCH 3/8] xapi-stdext-std: Delete unused xstringext methods

Signed-off-by: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Signed-off-by: Pau Ruiz Safont <pau.safont@vates.tech>
---
 .../lib/xapi-stdext-std/xstringext.ml         | 29 -------------------
 .../lib/xapi-stdext-std/xstringext.mli        | 24 ---------------
 .../lib/xapi-stdext-std/xstringext_test.ml    | 25 +---------------
 3 files changed, 1 insertion(+), 77 deletions(-)

diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
index 0512cc35dc5..0ef46aaf17a 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
@@ -12,31 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 module String = struct
-  let of_char c = String.make 1 c
-
-  let rev_map f string =
-    let n = String.length string in
-    String.init n (fun i -> f string.[n - i - 1])
-
-  let rev_iter f string =
-    for i = String.length string - 1 downto 0 do
-      f string.[i]
-    done
-
-  let fold_left f accu string =
-    let accu = ref accu in
-    for i = 0 to String.length string - 1 do
-      accu := f !accu string.[i]
-    done ;
-    !accu
-
-  let fold_right f string accu =
-    let accu = ref accu in
-    for i = String.length string - 1 downto 0 do
-      accu := f string.[i] !accu
-    done ;
-    !accu
-
   (** Returns true for whitespace characters, false otherwise *)
   let isspace = function ' ' | '\n' | '\r' | '\t' -> true | _ -> false
 
@@ -174,8 +149,4 @@ module String = struct
         String.escaped s
     | Some rules ->
         map_unlikely s (fun c -> List.assoc_opt c rules)
-
-  let sub_before c s = String.sub s 0 (String.index s c)
-
-  let sub_after c s = sub_to_end s (String.index s c + 1)
 end
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
index a890537c1de..356c59a5719 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
@@ -12,21 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 module String : sig
-  val of_char : char -> string
-
-  val rev_map : (char -> char) -> string -> string
-  (** Map a string to a string, applying the given function in reverse
-      order. *)
-
-  val rev_iter : (char -> unit) -> string -> unit
-  (** Iterate over the characters in a string in reverse order. *)
-
-  val fold_left : ('a -> char -> 'a) -> 'a -> string -> 'a
-  (** Fold over the characters in a string. *)
-
-  val fold_right : (char -> 'a -> 'a) -> string -> 'a -> 'a
-  (** Iterate over the characters in a string in reverse order. *)
-
   val isspace : char -> bool
   (** True if the character is whitespace *)
 
@@ -49,9 +34,6 @@ module String : sig
   val has_substr : string -> string -> bool
   (** True if sub is a substr of str *)
 
-  val find_all : string -> string -> int list
-  (** find all occurences of needle in haystack and return all their respective index *)
-
   val replace : string -> string -> string -> string
   (** replace all [f] substring in [s] by [t] *)
 
@@ -63,10 +45,4 @@ module String : sig
 
   val sub_to_end : string -> int -> string
   (** a substring from the specified position to the end of the string *)
-
-  val sub_before : char -> string -> string
-  (** a substring from the start of the string to the first occurrence of a given character, excluding the character *)
-
-  val sub_after : char -> string -> string
-  (** a substring from  the first occurrence of a given character to the end of the string, excluding the character *)
 end
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
index 4a70eb31899..dac312a92aa 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
@@ -27,22 +27,6 @@ let test_list tested_f (name, case, expected) =
   in
   (name, `Quick, check)
 
-let test_rev_map =
-  let spec_rev = [("", ""); ("foo bar", "rab oof")] in
-  let spec_func = [("id", Fun.id); ("uppercase_ascii", Char.uppercase_ascii)] in
-  let test (f_name, f) (case, expected) =
-    let expected = String.map f expected in
-    let name =
-      Printf.sprintf {|"%s" produces "%s" (%s)|} case expected f_name
-    in
-    test_string (XString.rev_map f) (name, case, expected)
-  in
-  let tests =
-    (* Generate the product of the two lists to generate the tests *)
-    List.concat_map (fun func -> List.map (test func) spec_rev) spec_func
-  in
-  ("rev_map", tests)
-
 let test_split =
   let test limit (splitter, splitted, expected) =
     let split = XString.split ~limit in
@@ -168,11 +152,4 @@ let test_escaped =
 
 let () =
   Alcotest.run "Xstringext"
-    [
-      test_rev_map
-    ; test_split
-    ; test_split_f
-    ; test_has_substr
-    ; test_rtrim
-    ; test_escaped
-    ]
+    [test_split; test_split_f; test_has_substr; test_rtrim; test_escaped]

From 1174f3a86f48512adac5a0fffe02725016a82ce3 Mon Sep 17 00:00:00 2001
From: Pau Ruiz Safont <pau.safont@vates.tech>
Date: Fri, 12 Dec 2025 15:37:44 +0000
Subject: [PATCH 4/8] xapi-stdext-std: Remove String.escaped, add
 String.replaced
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

String.replaced is an alias of map_unlikely. This names makes the intent
of the function clearer. Because a function to replace the characters is
exposed, users are less likely to fall into the pitfall of using lists.

Lists not only are very slow, but allow users to have more than one
replacement rule per character, possibly introducing mistakes.

If a plain match function cannot be produced and a list needs to be used,
users can convert it to a Char.Map and do the match with a find_opt.
This approach ends up being ~60-70% faster than using plain lists.

The benchmark comparing the new approach with the old one:

  String size 100:
    Optimized: 236.556 μs
    Reference: 1861.600 μs
    Improvement: 87.3% faster

  String size 500:
    Optimized: 1099.030 μs
    Reference: 9665.405 μs
    Improvement: 88.6% faster

  String size 1000:
    Optimized: 2198.777 μs
    Reference: 19115.019 μs
    Improvement: 88.5% faster

Signed-off-by: Pau Ruiz Safont <pau.safont@vates.tech>
---
 ocaml/idl/markdown_backend.ml                 | 38 +++++------
 ocaml/libs/http-lib/dune                      |  1 +
 ocaml/libs/http-lib/http_svr.ml               | 40 +++++-------
 ocaml/libs/http-lib/http_svr.mli              |  3 +
 .../xapi-stdext-std/bench/bench_xstringext.ml | 64 +++++++++++--------
 .../lib/xapi-stdext-std/xstringext.ml         |  7 +-
 .../lib/xapi-stdext-std/xstringext.mli        |  8 +--
 .../lib/xapi-stdext-std/xstringext_test.ml    | 38 +----------
 ocaml/xapi-cli-server/cli_printer.ml          | 12 +++-
 ocaml/xapi/fileserver.ml                      | 14 +---
 10 files changed, 92 insertions(+), 133 deletions(-)

diff --git a/ocaml/idl/markdown_backend.ml b/ocaml/idl/markdown_backend.ml
index ca067ef9dcb..3125d850b85 100644
--- a/ocaml/idl/markdown_backend.ml
+++ b/ocaml/idl/markdown_backend.ml
@@ -43,41 +43,41 @@ let compare_case_ins x y =
   compare (String.lowercase_ascii x) (String.lowercase_ascii y)
 
 let escape s =
-  let esc_char = function
+  let replace = function
     | '\\' ->
-        "&#92;"
+        Some "&#92;"
     | '*' ->
-        "&#42;"
+        Some "&#42;"
     | '_' ->
-        "&#95;"
+        Some "&#95;"
     | '{' ->
-        "&#123;"
+        Some "&#123;"
     | '}' ->
-        "&#125;"
+        Some "&#125;"
     | '[' ->
-        "&#91;"
+        Some "&#91;"
     | ']' ->
-        "&#93;"
+        Some "&#93;"
     | '(' ->
-        "&#40;"
+        Some "&#40;"
     | ')' ->
-        "&#41;"
+        Some "&#41;"
     | '>' ->
-        "&gt;"
+        Some "&gt;"
     | '<' ->
-        "&lt;"
+        Some "&lt;"
     | '#' ->
-        "&#35;"
+        Some "&#35;"
     | '+' ->
-        "&#43;"
+        Some "&#43;"
     | '-' ->
-        "&#45;"
+        Some "&#45;"
     | '!' ->
-        "&#33;"
-    | c ->
-        String.make 1 c
+        Some "&#33;"
+    | _ ->
+        None
   in
-  String.to_seq s |> Seq.map esc_char |> List.of_seq |> String.concat ""
+  Xapi_stdext_std.Xstringext.String.replaced ~replace s
 
 let rec of_ty_verbatim = function
   | SecretString | String ->
diff --git a/ocaml/libs/http-lib/dune b/ocaml/libs/http-lib/dune
index 4e8d255b6bd..ac6db1b23d4 100644
--- a/ocaml/libs/http-lib/dune
+++ b/ocaml/libs/http-lib/dune
@@ -63,6 +63,7 @@
   xapi-backtrace
   xapi-log
   xapi-stdext-pervasives
+  xapi-stdext-std
   xapi-stdext-threads
   xapi-stdext-unix))
 
diff --git a/ocaml/libs/http-lib/http_svr.ml b/ocaml/libs/http-lib/http_svr.ml
index 7c5ecc393d1..6271c5ad987 100644
--- a/ocaml/libs/http-lib/http_svr.ml
+++ b/ocaml/libs/http-lib/http_svr.ml
@@ -331,28 +331,22 @@ module Server = struct
       x.handlers []
 end
 
-let escape uri =
-  (* from xapi-stdext-std xstringext *)
-  let escaped ~rules string =
-    let aux h t =
-      ( if List.mem_assoc h rules then
-          List.assoc h rules
-        else
-          Astring.String.of_char h
+let escape_html uri =
+  Xapi_stdext_std.Xstringext.String.replaced
+    ~replace:(function
+      | '<' ->
+          Some "&lt;"
+      | '>' ->
+          Some "&gt;"
+      | '\'' ->
+          Some "&apos;"
+      | '"' ->
+          Some "&quot;"
+      | '&' ->
+          Some "&amp;"
+      | _ ->
+          None
       )
-      :: t
-    in
-    String.concat "" (Astring.String.fold_right aux string [])
-  in
-  escaped
-    ~rules:
-      [
-        ('<', "&lt;")
-      ; ('>', "&gt;")
-      ; ('\'', "&apos;")
-      ; ('"', "&quot;")
-      ; ('&', "&amp;")
-      ]
     uri
 
 exception Generic_error of string
@@ -508,7 +502,7 @@ let read_request ?proxy_seen ~read_timeout ~total_timeout ~max_length fd =
                 )
         | exc ->
             response_internal_error exc fd
-              ~extra:(escape (Printexc.to_string exc))
+              ~extra:(escape_html (Printexc.to_string exc))
     ) ;
     (None, None)
 
@@ -557,7 +551,7 @@ let handle_one (x : 'a Server.t) ss context req =
                 )
         | exc ->
             response_internal_error ~req exc ss
-              ~extra:(escape (Printexc.to_string exc))
+              ~extra:(escape_html (Printexc.to_string exc))
     ) ;
     !finished
 
diff --git a/ocaml/libs/http-lib/http_svr.mli b/ocaml/libs/http-lib/http_svr.mli
index 61b49e7b3f2..cf335592d7b 100644
--- a/ocaml/libs/http-lib/http_svr.mli
+++ b/ocaml/libs/http-lib/http_svr.mli
@@ -68,6 +68,9 @@ val start :
 
 val handle_one : 'a Server.t -> Unix.file_descr -> 'a -> Http.Request.t -> bool
 
+val escape_html : string -> string
+(** Escapes HTML: replaces characters with their character references *)
+
 exception Socket_not_found
 
 val stop : socket -> unit
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/bench/bench_xstringext.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/bench/bench_xstringext.ml
index 52897ee2a0c..d302737b1b1 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/bench/bench_xstringext.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/bench/bench_xstringext.ml
@@ -8,36 +8,42 @@ let make_string len = String.init len (fun i -> Char.chr (33 + (i mod 94)))
 let escape_rules =
   [('a', "[A]"); ('e', "[E]"); ('i', "[I]"); ('o', "[O]"); ('u', "[U]")]
 
-(* Reference implementation from xstringext_test.ml *)
-let escaped_spec ?rules string =
-  match rules with
-  | None ->
-      String.escaped string
-  | Some rules ->
-      let apply_rules char =
-        match List.assoc_opt char rules with
-        | None ->
-            Seq.return char
-        | Some replacement ->
-            String.to_seq replacement
-      in
-      string |> String.to_seq |> Seq.concat_map apply_rules |> String.of_seq
+let replace = function
+  | 'a' ->
+      Some "[A]"
+  | 'e' ->
+      Some "[E]"
+  | 'i' ->
+      Some "[I]"
+  | 'o' ->
+      Some "[O]"
+  | 'u' ->
+      Some "[U]"
+  | _ ->
+      None
+
+(* Reference implementation using lists *)
+let replaced_spec ~rules string =
+  let apply_rules char = List.assoc_opt char rules in
+  XString.replaced ~replace:apply_rules string
 
-let escaped_benchmark n =
+let replaced ~rules string = XString.replaced ~replace:rules string
+
+let replaced_benchmark n =
   let s = make_string n in
-  Staged.stage @@ fun () -> ignore (XString.escaped ~rules:escape_rules s)
+  Staged.stage @@ fun () -> ignore (replaced ~rules:replace s)
 
-let escaped_spec_benchmark n =
+let replaced_spec_benchmark n =
   let s = make_string n in
-  Staged.stage @@ fun () -> ignore (escaped_spec ~rules:escape_rules s)
+  Staged.stage @@ fun () -> ignore (replaced_spec ~rules:escape_rules s)
 
-let test_escaped =
-  Test.make_indexed ~name:"escaped" ~fmt:"%s %d" ~args:[100; 500; 1000]
-    escaped_benchmark
+let test_replaced =
+  Test.make_indexed ~name:"replaced" ~fmt:"%s %d" ~args:[100; 500; 1000]
+    replaced_benchmark
 
-let test_escaped_spec =
-  Test.make_indexed ~name:"escaped-spec" ~fmt:"%s %d" ~args:[100; 500; 1000]
-    escaped_spec_benchmark
+let test_replaced_spec =
+  Test.make_indexed ~name:"replaced-spec" ~fmt:"%s %d" ~args:[100; 500; 1000]
+    replaced_spec_benchmark
 
 let benchmark () =
   let ols =
@@ -50,8 +56,8 @@ let benchmark () =
     Benchmark.cfg ~limit:2000 ~quota:(Time.second 0.5) ~kde:(Some 1000) ()
   in
   let test =
-    Test.make_grouped ~name:"escaped-comparison"
-      [test_escaped; test_escaped_spec]
+    Test.make_grouped ~name:"replaced-comparison"
+      [test_replaced; test_replaced_spec]
   in
   let raw_results = Benchmark.all cfg instances test in
   let results =
@@ -97,8 +103,10 @@ let () =
   List.iter
     (fun size ->
       Printf.printf "String size %s:\n" size ;
-      let opt_test = Printf.sprintf "escaped-comparison/escaped %s" size in
-      let ref_test = Printf.sprintf "escaped-comparison/escaped-spec %s" size in
+      let opt_test = Printf.sprintf "replaced-comparison/replaced %s" size in
+      let ref_test =
+        Printf.sprintf "replaced-comparison/replaced-spec %s" size
+      in
       match (get_timing opt_test, get_timing ref_test) with
       | Some opt_time, Some ref_time ->
           let improvement = (ref_time -. opt_time) /. ref_time *. 100.0 in
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
index 0ef46aaf17a..75746417e40 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
@@ -143,10 +143,5 @@ module String = struct
     ) else
       s
 
-  let escaped ?rules s =
-    match rules with
-    | None ->
-        String.escaped s
-    | Some rules ->
-        map_unlikely s (fun c -> List.assoc_opt c rules)
+  let replaced ~replace s = map_unlikely s replace
 end
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
index 356c59a5719..ab123eb5c98 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
@@ -15,10 +15,10 @@ module String : sig
   val isspace : char -> bool
   (** True if the character is whitespace *)
 
-  val escaped : ?rules:(char * string) list -> string -> string
-  (** Backward-compatible string escaping, defaulting to the built-in
-      	OCaml string escaping but allowing an arbitrary mapping from characters
-      	to strings. *)
+  val replaced : replace:(char -> string option) -> string -> string
+  (** [replaced ~replacement str] applies [replace] to all characters in [str]
+      and when it returns [Some rep] the character is replaced with [rep] in
+      the resulting string *)
 
   val split_f : (char -> bool) -> string -> string list
   (** Take a predicate and a string, return a list of strings separated by
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
index dac312a92aa..13eb45c6c01 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
@@ -114,42 +114,6 @@ let test_rtrim =
   in
   ("rtrim", List.map test spec)
 
-(** Simple implementation of escaped for testing against *)
-let escaped_spec ?rules string =
-  match rules with
-  | None ->
-      String.escaped string
-  | Some rules ->
-      let apply_rules char =
-        match List.assoc_opt char rules with
-        | None ->
-            Seq.return char
-        | Some replacement ->
-            String.to_seq replacement
-      in
-      string |> String.to_seq |> Seq.concat_map apply_rules |> String.of_seq
-
-let test_escaped =
-  let open QCheck2 in
-  (* Generator for escape rules: list of (char, string) mappings *)
-  let gen_rules =
-    let open Gen in
-    let gen_rule = pair char (string_size (int_range 0 5) ~gen:char) in
-    list gen_rule
-  in
-  (* Generator for test input: string and optional rules *)
-  let gen_input = Gen.pair Gen.string (Gen.opt gen_rules) in
-  let property (s, rules) =
-    let expected = escaped_spec ?rules s in
-    let actual = XString.escaped ?rules s in
-    String.equal expected actual
-  in
-  let test =
-    Test.make ~name:"escaped matches reference implementation" ~count:1000
-      gen_input property
-  in
-  ("escaped", [QCheck_alcotest.to_alcotest test])
-
 let () =
   Alcotest.run "Xstringext"
-    [test_split; test_split_f; test_has_substr; test_rtrim; test_escaped]
+    [test_split; test_split_f; test_has_substr; test_rtrim]
diff --git a/ocaml/xapi-cli-server/cli_printer.ml b/ocaml/xapi-cli-server/cli_printer.ml
index 1fc1d5586fd..bb627812924 100644
--- a/ocaml/xapi-cli-server/cli_printer.ml
+++ b/ocaml/xapi-cli-server/cli_printer.ml
@@ -47,9 +47,15 @@ let rec multi_line_record r =
 
 (* Used to escape commas in --minimal mode *)
 let escape_commas x =
-  (* Escaping rules: *)
-  let rules = [(',', "\\,"); (* , -> \, *) ('\\', "\\\\") (* \ -> \\ *)] in
-  Xapi_stdext_std.Xstringext.String.escaped ~rules x
+  let replace = function
+    | ',' ->
+        Some "\\,"
+    | '\\' ->
+        Some "\\\\"
+    | _ ->
+        None
+  in
+  Xapi_stdext_std.Xstringext.String.replaced ~replace x
 
 let make_printer sock minimal =
   let buffer = ref [] in
diff --git a/ocaml/xapi/fileserver.ml b/ocaml/xapi/fileserver.ml
index 7c29441df35..8c83dac57f3 100644
--- a/ocaml/xapi/fileserver.ml
+++ b/ocaml/xapi/fileserver.ml
@@ -22,23 +22,11 @@ module D = Debug.Make (struct let name = "fileserver" end)
 
 open D
 
-let escape uri =
-  Xstringext.escaped
-    ~rules:
-      [
-        ('<', "&lt;")
-      ; ('>', "&gt;")
-      ; ('\'', "&apos;")
-      ; ('"', "&quot;")
-      ; ('&', "&amp;")
-      ]
-    uri
-
 let missing uri =
   "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\"> <html><head> \
    <title>404 Not Found</title> </head><body> <h1>Not Found</h1> <p>The \
    requested URL "
-  ^ escape uri
+  ^ Http_svr.escape_html uri
   ^ " was not found on this server.</p> <hr><address>Xapi \
      Server</address></body></html>"
 

From e41ce966bb31b0ec14d14cd0e5b1e94e05ea84e7 Mon Sep 17 00:00:00 2001
From: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Date: Tue, 21 May 2024 16:27:58 +0100
Subject: [PATCH 5/8] xapi-stdext-std: Replace String.has_substr with Astring's
 is_infix

Not only it's more efficient, but it's also more ergonomic

Signed-off-by: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Signed-off-by: Pau Ruiz Safont <pau.safont@vates.tech>
---
 ocaml/libs/sexpr/sExpr.ml                     |  2 +-
 .../lib/xapi-stdext-std/xstringext.ml         | 11 --------
 .../lib/xapi-stdext-std/xstringext.mli        |  3 ---
 .../lib/xapi-stdext-std/xstringext_test.ml    | 27 +------------------
 ocaml/quicktest/quicktest_http.ml             |  6 ++---
 ocaml/xapi/extauth_plugin_ADpbis.ml           |  2 +-
 ocaml/xapi/map_check.ml                       |  2 +-
 ocaml/xapi/rbac_audit.ml                      |  5 ++--
 8 files changed, 8 insertions(+), 50 deletions(-)

diff --git a/ocaml/libs/sexpr/sExpr.ml b/ocaml/libs/sexpr/sExpr.ml
index 3637ac6abf5..c9794265d49 100644
--- a/ocaml/libs/sexpr/sExpr.ml
+++ b/ocaml/libs/sexpr/sExpr.ml
@@ -28,7 +28,7 @@ let is_escape_char = function '\\' | '\'' -> true | _ -> false
 (* XXX: This escapes "'c'" and "\'c\'" to "\\'c\\'".
  * They are both unescaped as "'c'". They have been ported
  * to make sure that this corner case is left unchanged.
- * It is worth investigating the use of 
+ * It is worth investigating the use of
  * - Astring.String.Ascii.escape_string
  * - Astring.String.Ascii.unescape
  * that have guaranteed invariants and optimised performances *)
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
index 75746417e40..f23bfbe0fb0 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
@@ -58,17 +58,6 @@ module String = struct
     else
       s
 
-  (** has_substr str sub returns true if sub is a substring of str. Simple, naive, slow. *)
-  let has_substr str sub =
-    if String.length sub > String.length str then
-      false
-    else
-      let result = ref false in
-      for start = 0 to String.length str - String.length sub do
-        if String.sub str start (String.length sub) = sub then result := true
-      done ;
-      !result
-
   (** find all occurences of needle in haystack and return all their respective index *)
   let find_all needle haystack =
     let m = String.length needle and n = String.length haystack in
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
index ab123eb5c98..31292bd69d5 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
@@ -31,9 +31,6 @@ module String : sig
   val rtrim : string -> string
   (** FIXME document me|remove me if similar to strip *)
 
-  val has_substr : string -> string -> bool
-  (** True if sub is a substr of str *)
-
   val replace : string -> string -> string -> string
   (** replace all [f] substring in [s] by [t] *)
 
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
index 13eb45c6c01..a603fb1d365 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
@@ -13,10 +13,6 @@
 
 module XString = Xapi_stdext_std.Xstringext.String
 
-let test_boolean tested_f (name, case, expected) =
-  let check () = Alcotest.(check bool) name expected (tested_f case) in
-  (name, `Quick, check)
-
 let test_string tested_f (name, case, expected) =
   let check () = Alcotest.(check string) name expected (tested_f case) in
   (name, `Quick, check)
@@ -74,26 +70,6 @@ let test_split_f =
   let tests = List.map test specs in
   ("split_f", tests)
 
-let test_has_substr =
-  let spec =
-    [
-      ("", "", true)
-    ; ("", "foo bar", true)
-    ; ("f", "foof", true)
-    ; ("foofo", "foof", false)
-    ; ("foof", "foof", true)
-    ; ("f", "foof", true)
-    ; ("fo", "foof", true)
-    ; ("of", "foof", true)
-    ; ("ff", "foof", false)
-    ]
-  in
-  let test (contained, container, expected) =
-    let name = Printf.sprintf {|"%s" in "%s"|} contained container in
-    test_boolean (XString.has_substr container) (name, contained, expected)
-  in
-  ("has_substr", List.map test spec)
-
 let test_rtrim =
   let spec =
     [
@@ -115,5 +91,4 @@ let test_rtrim =
   ("rtrim", List.map test spec)
 
 let () =
-  Alcotest.run "Xstringext"
-    [test_split; test_split_f; test_has_substr; test_rtrim]
+  Alcotest.run "Xstringext" [test_split; test_split_f; test_rtrim]
diff --git a/ocaml/quicktest/quicktest_http.ml b/ocaml/quicktest/quicktest_http.ml
index 86f9660e7ce..d718a61a9e7 100644
--- a/ocaml/quicktest/quicktest_http.ml
+++ b/ocaml/quicktest/quicktest_http.ml
@@ -99,7 +99,7 @@ module Cookies = struct
       match body with
       | first_line :: _ ->
           D.warn "expected = [%s]; received = [%s]" expected first_line ;
-          Xapi_stdext_std.Xstringext.String.has_substr first_line expected
+          Astring.String.is_infix ~affix:first_line expected
       | _ ->
           false
     in
@@ -210,9 +210,7 @@ module HTML_Escaping = struct
   let bad_command_exp = "&lt;&gt;&apos;\\&quot;&amp;"
 
   let html_escaping expected cmd =
-    let check_result b =
-      Xapi_stdext_std.Xstringext.String.has_substr b expected
-    in
+    let check_result = Astring.String.is_infix ~affix:expected in
     let _, _, _, body = Uds.http_command Xapi_globs.unix_domain_socket cmd in
     match body with
     | first_line :: _ ->
diff --git a/ocaml/xapi/extauth_plugin_ADpbis.ml b/ocaml/xapi/extauth_plugin_ADpbis.ml
index 6c532c8eb70..070d2a8a8c4 100644
--- a/ocaml/xapi/extauth_plugin_ADpbis.ml
+++ b/ocaml/xapi/extauth_plugin_ADpbis.ml
@@ -238,7 +238,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
       pbis_cmd ^ " " ^ List.fold_left (fun p pp -> p ^ " " ^ pp) " " pbis_args
     in
     let debug_cmd =
-      if Stringext.has_substr debug_cmd "--password" then
+      if Astring.String.is_infix ~affix:"--password" debug_cmd then
         "(omitted for security)"
       else
         debug_cmd
diff --git a/ocaml/xapi/map_check.ml b/ocaml/xapi/map_check.ml
index 503ccd2ce8a..3737b3f00bf 100644
--- a/ocaml/xapi/map_check.ml
+++ b/ocaml/xapi/map_check.ml
@@ -113,7 +113,7 @@ let assert_value ~field ~key ~attr ~value =
           | Some v ->
               if acc = "" then
                 v
-              else if Xapi_stdext_std.Xstringext.String.has_substr acc v then
+              else if Astring.String.is_infix ~affix:v acc then
                 err value
               else
                 v ^ "," ^ acc
diff --git a/ocaml/xapi/rbac_audit.ml b/ocaml/xapi/rbac_audit.ml
index bbc5a7a6fc9..d0f94f6775b 100644
--- a/ocaml/xapi/rbac_audit.ml
+++ b/ocaml/xapi/rbac_audit.ml
@@ -362,8 +362,7 @@ and
 
 let has_to_audit action =
   let has_side_effect action =
-    not (Xapi_stdext_std.Xstringext.String.has_substr action ".get")
-    (* TODO: a bit slow? *)
+    not (Astring.String.is_infix ~affix:".get" action)
   in
   (!Xapi_globs.log_getter || has_side_effect action)
   && not
@@ -471,7 +470,7 @@ let allowed_pre_fn ~__context ~action ?args () =
     if
       has_to_audit action
       (* for now, we only cache arg results for destroy actions *)
-      && Xapi_stdext_std.Xstringext.String.has_substr action ".destroy"
+      && Astring.String.is_infix ~affix:".destroy" action
     then
       let args' = add_dummy_args __context action args in
       Some (sexpr_of_parameters __context action args')

From dd040a9f59718a3507367b316e3a0991a585d439 Mon Sep 17 00:00:00 2001
From: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Date: Tue, 21 May 2024 16:34:22 +0100
Subject: [PATCH 6/8] xapi-stdext-std: replace String.filter_chars with
 Astring.filter

The former didn't have any tests and the performance is unknown

Signed-off-by: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Signed-off-by: Pau Ruiz Safont <pau.safont@vates.tech>
---
 ocaml/libs/tgroup/dune                             |  2 +-
 ocaml/libs/tgroup/tgroup.ml                        |  3 +--
 .../xapi-stdext/lib/xapi-stdext-std/xstringext.ml  | 14 --------------
 .../xapi-stdext/lib/xapi-stdext-std/xstringext.mli |  3 ---
 ocaml/xe-cli/dune                                  |  1 -
 ocaml/xe-cli/newcli.ml                             |  3 +--
 6 files changed, 3 insertions(+), 23 deletions(-)

diff --git a/ocaml/libs/tgroup/dune b/ocaml/libs/tgroup/dune
index 6c152a5c2ef..12070176651 100644
--- a/ocaml/libs/tgroup/dune
+++ b/ocaml/libs/tgroup/dune
@@ -2,7 +2,7 @@
  (name tgroup)
  (modules tgroup)
  (public_name tgroup)
- (libraries unix xapi-log xapi-stdext-unix xapi-stdext-std))
+ (libraries astring unix xapi-log xapi-stdext-unix))
 
 (test
  (name test_tgroup)
diff --git a/ocaml/libs/tgroup/tgroup.ml b/ocaml/libs/tgroup/tgroup.ml
index 071a9dfe0d2..e5b163fea60 100644
--- a/ocaml/libs/tgroup/tgroup.ml
+++ b/ocaml/libs/tgroup/tgroup.ml
@@ -70,8 +70,7 @@ module Group = struct
       | _ ->
           false
 
-    let sanitize s =
-      Xapi_stdext_std.Xstringext.String.filter_chars s is_alphanum
+    let sanitize s = Astring.String.filter is_alphanum s
 
     let make ?user_agent subject_sid =
       let user_agent =
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
index f23bfbe0fb0..07370794b15 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
@@ -98,20 +98,6 @@ module String = struct
     ) else
       s
 
-  let filter_chars s valid =
-    let badchars = ref false in
-    let buf = Buffer.create 0 in
-    for i = 0 to String.length s - 1 do
-      if !badchars then (
-        if valid s.[i] then
-          Buffer.add_char buf s.[i]
-      ) else if not (valid s.[i]) then (
-        Buffer.add_substring buf s 0 i ;
-        badchars := true
-      )
-    done ;
-    if !badchars then Buffer.contents buf else s
-
   let map_unlikely s f =
     let changed = ref false in
     let m = ref 0 in
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
index 31292bd69d5..17339e3321b 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
@@ -34,9 +34,6 @@ module String : sig
   val replace : string -> string -> string -> string
   (** replace all [f] substring in [s] by [t] *)
 
-  val filter_chars : string -> (char -> bool) -> string
-  (** filter chars from a string *)
-
   val map_unlikely : string -> (char -> string option) -> string
   (** map a string trying to fill the buffer by chunk *)
 
diff --git a/ocaml/xe-cli/dune b/ocaml/xe-cli/dune
index b61ec3cde63..3aed1017987 100644
--- a/ocaml/xe-cli/dune
+++ b/ocaml/xe-cli/dune
@@ -17,7 +17,6 @@
     xapi-backtrace
     xapi-cli-protocol
     xapi-stdext-pervasives
-    xapi-stdext-std
     xapi-stdext-unix
   )
 )
diff --git a/ocaml/xe-cli/newcli.ml b/ocaml/xe-cli/newcli.ml
index e8b7179e372..0b18d57dd18 100644
--- a/ocaml/xe-cli/newcli.ml
+++ b/ocaml/xe-cli/newcli.ml
@@ -13,7 +13,6 @@
  *)
 (* New cli talking to the in-server cli interface *)
 
-module Stringext = Xapi_stdext_std.Xstringext.String
 open Xapi_stdext_pervasives
 open Cli_protocol
 
@@ -306,7 +305,7 @@ let parse_args =
             || (extra_args.[!i] = ',' && extra_args.[!i - 1] <> '\\')
           then (
           let seg = String.sub extra_args !pos (!i - !pos) in
-          l := Stringext.filter_chars seg (( <> ) '\\') :: !l ;
+          l := Astring.String.filter (( <> ) '\\') seg :: !l ;
           incr i ;
           pos := !i
         ) else

From 8648ebba94a5bdce4c9401cfc284c66963d75570 Mon Sep 17 00:00:00 2001
From: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Date: Tue, 21 May 2024 17:16:09 +0100
Subject: [PATCH 7/8] xapi-stdext-std: replace String.split_f with Astring
 functions

This also allows to drop String.isspace

Signed-off-by: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Signed-off-by: Pau Ruiz Safont <pau.safont@vates.tech>
---
 .../lib/xapi-stdext-std/xstringext.ml         | 26 -------------------
 .../lib/xapi-stdext-std/xstringext.mli        |  8 ------
 .../lib/xapi-stdext-std/xstringext_test.ml    | 21 +--------------
 ocaml/tests/test_guest_agent.ml               | 20 ++++----------
 ocaml/xapi/extauth_plugin_ADpbis.ml           | 18 ++++++-------
 ocaml/xapi/workload_balancing.ml              | 26 +++++--------------
 ocaml/xapi/xapi_globs.ml                      |  6 ++---
 ocaml/xapi/xapi_host_crashdump.ml             |  7 +++--
 ocaml/xapi/xapi_pif.ml                        |  7 ++---
 ocaml/xapi/xha_interface.ml                   |  5 ++--
 10 files changed, 34 insertions(+), 110 deletions(-)

diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
index 07370794b15..1c205b31faa 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
@@ -12,32 +12,6 @@
  * GNU Lesser General Public License for more details.
  *)
 module String = struct
-  (** Returns true for whitespace characters, false otherwise *)
-  let isspace = function ' ' | '\n' | '\r' | '\t' -> true | _ -> false
-
-  let split_f p str =
-    let split_one seq =
-      let not_p c = not (p c) in
-      let a = Seq.take_while not_p seq in
-      let b = Seq.drop_while not_p seq in
-      (a, b)
-    in
-    let drop seq = Seq.drop_while p seq in
-    let rec split acc chars =
-      if Seq.is_empty chars then
-        acc
-      else
-        let a, b = split_one chars in
-        let b = drop b in
-        let acc = if Seq.is_empty a then acc else Seq.cons a acc in
-        split acc b
-    in
-    String.to_seq str
-    |> split Seq.empty
-    |> Seq.map String.of_seq
-    |> List.of_seq
-    |> List.rev
-
   let sub_to_end s start =
     let length = String.length s in
     String.sub s start (length - start)
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
index 17339e3321b..e2ba23e0139 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
@@ -12,19 +12,11 @@
  * GNU Lesser General Public License for more details.
  *)
 module String : sig
-  val isspace : char -> bool
-  (** True if the character is whitespace *)
-
   val replaced : replace:(char -> string option) -> string -> string
   (** [replaced ~replacement str] applies [replace] to all characters in [str]
       and when it returns [Some rep] the character is replaced with [rep] in
       the resulting string *)
 
-  val split_f : (char -> bool) -> string -> string list
-  (** Take a predicate and a string, return a list of strings separated by
-      runs of characters where the predicate was true. Avoid if possible, it's
-      very costly to execute. *)
-
   val split : limit:int -> char -> string -> string list
   (** split a string on a single char *)
 
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
index a603fb1d365..4fe39225785 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml
@@ -52,24 +52,6 @@ let test_split =
   in
   ("split", tests)
 
-let test_split_f =
-  let specs =
-    [
-      (XString.isspace, "foo bar", ["foo"; "bar"])
-    ; (XString.isspace, "foo  bar", ["foo"; "bar"])
-    ; (XString.isspace, "foo \n\t\r bar", ["foo"; "bar"])
-    ; (XString.isspace, " foo bar ", ["foo"; "bar"])
-    ; (XString.isspace, "", [])
-    ; (XString.isspace, " ", [])
-    ]
-  in
-  let test (splitter, splitted, expected) =
-    let name = Printf.sprintf {|"%s"|} (String.escaped splitted) in
-    test_list (XString.split_f splitter) (name, splitted, expected)
-  in
-  let tests = List.map test specs in
-  ("split_f", tests)
-
 let test_rtrim =
   let spec =
     [
@@ -90,5 +72,4 @@ let test_rtrim =
   in
   ("rtrim", List.map test spec)
 
-let () =
-  Alcotest.run "Xstringext" [test_split; test_split_f; test_rtrim]
+let () = Alcotest.run "Xstringext" [test_split; test_rtrim]
diff --git a/ocaml/tests/test_guest_agent.ml b/ocaml/tests/test_guest_agent.ml
index 6bc0f227c7b..94774ac10c7 100644
--- a/ocaml/tests/test_guest_agent.ml
+++ b/ocaml/tests/test_guest_agent.ml
@@ -42,9 +42,7 @@ module Networks = Generic.MakeStateless (struct
     )
 
   let construct_tree tree path =
-    let nodes =
-      Xapi_stdext_std.Xstringext.String.split_f (fun s -> s = '/') path
-    in
+    let nodes = Astring.String.cuts ~empty:false ~sep:"/" path in
     add_path_to_tree tree nodes
 
   let rec list_helper children = function
@@ -60,9 +58,7 @@ module Networks = Generic.MakeStateless (struct
     )
 
   let list (T (_root, children)) path =
-    let nodes =
-      Xapi_stdext_std.Xstringext.String.split_f (fun s -> s = '/') path
-    in
+    let nodes = Astring.String.cuts ~empty:false ~sep:"/" path in
     list_helper children nodes
 
   let transform input =
@@ -231,9 +227,7 @@ module Initial_guest_metrics = Generic.MakeStateless (struct
     )
 
   let construct_mtree mtree (path, leaf_value) =
-    let nodes =
-      Xapi_stdext_std.Xstringext.String.split_f (fun s -> s = '/') path
-    in
+    let nodes = Astring.String.cuts ~empty:false ~sep:"/" path in
     add_leaf_to_mtree nodes leaf_value mtree
 
   let rec list_helper children = function
@@ -254,9 +248,7 @@ module Initial_guest_metrics = Generic.MakeStateless (struct
     | Lf (_, _) ->
         []
     | Mt (_, children) ->
-        let nodes =
-          Xapi_stdext_std.Xstringext.String.split_f (fun s -> s = '/') path
-        in
+        let nodes = Astring.String.cuts ~empty:false ~sep:"/" path in
         list_helper children nodes
 
   let rec lookup_helper mtree = function
@@ -274,9 +266,7 @@ module Initial_guest_metrics = Generic.MakeStateless (struct
     )
 
   let lookup mtree path =
-    let nodes =
-      Xapi_stdext_std.Xstringext.String.split_f (fun s -> s = '/') path
-    in
+    let nodes = Astring.String.cuts ~empty:false ~sep:"/" path in
     lookup_helper mtree nodes
 
   let transform input =
diff --git a/ocaml/xapi/extauth_plugin_ADpbis.ml b/ocaml/xapi/extauth_plugin_ADpbis.ml
index 070d2a8a8c4..dac47414b33 100644
--- a/ocaml/xapi/extauth_plugin_ADpbis.ml
+++ b/ocaml/xapi/extauth_plugin_ADpbis.ml
@@ -92,6 +92,8 @@ module Lwsmd = struct
     )
 end
 
+let is_word_sep = function '(' | ')' | ' ' | '\t' | '.' -> true | _ -> false
+
 let match_error_tag (lines : string list) =
   let err_catch_list =
     [
@@ -105,8 +107,7 @@ let match_error_tag (lines : string list) =
     ]
   in
   let split_to_words str =
-    let seps = ['('; ')'; ' '; '\t'; '.'] in
-    Stringext.split_f (fun s -> List.exists (fun sep -> sep = s) seps) str
+    Astring.String.fields ~empty:false ~is_sep:is_word_sep str
   in
   let rec has_err lines err_pattern =
     match lines with
@@ -133,7 +134,7 @@ let extract_sid_from_group_list group_list =
     (fun (_, v) ->
       let v = Stringext.replace ")" "" v in
       let v = Stringext.replace "sid =" "|" v in
-      let vs = Stringext.split_f (fun c -> c = '|') v in
+      let vs = Astring.String.cuts ~empty:false ~sep:"|" v in
       let sid = String.trim (List.nth vs 1) in
       debug "extract_sid_from_group_list get sid=[%s]" sid ;
       sid
@@ -166,7 +167,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
     Locking_helpers.Named_mutex.create "IS_SERVER_AVAILABLE"
 
   let splitlines s =
-    Stringext.split_f (fun c -> c = '\n') (Stringext.replace "#012" "\n" s)
+    Astring.String.cuts ~empty:false ~sep:"\n" (Stringext.replace "#012" "\n" s)
 
   let pbis_common_with_password (password : string) (pbis_cmd : string)
       (pbis_args : string list) =
@@ -350,9 +351,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
             !exited_code
             (Stringext.replace "\n" ";" !output) ;
           let split_to_words s =
-            Stringext.split_f
-              (fun c -> c = '(' || c = ')' || c = '.' || c = ' ')
-              s
+            Astring.String.fields ~empty:false ~is_sep:is_word_sep s
           in
           let revlines =
             List.rev
@@ -621,7 +620,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
     (* first, we try to authenticated user against our external user database *)
     (* pbis_common will raise an Auth_failure if external authentication fails *)
     let domain, user =
-      match Stringext.split_f (fun c -> c = '\\') username with
+      match Astring.String.cuts ~empty:false ~sep:"\\" username with
       | [domain; user] ->
           (domain, user)
       | [user] ->
@@ -978,7 +977,8 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
             | "" ->
                 []
             | disabled_modules_string ->
-                Stringext.split_f (fun c -> c = ',') disabled_modules_string
+                Astring.String.cuts ~empty:false ~sep:","
+                  disabled_modules_string
           with Not_found -> []
         in
         let disabled_module_params =
diff --git a/ocaml/xapi/workload_balancing.ml b/ocaml/xapi/workload_balancing.ml
index 47124c1f355..136aa2c8985 100644
--- a/ocaml/xapi/workload_balancing.ml
+++ b/ocaml/xapi/workload_balancing.ml
@@ -74,26 +74,12 @@ let raise_internal_error args =
   raise (Api_errors.Server_error (Api_errors.wlb_internal_error, args))
 
 let split_host_port url =
-  try
-    if url.[0] = '[' then (
-      (* IPv6 *)
-      let host_end = String.rindex url ']' in
-      if url.[host_end + 1] <> ':' then
-        raise_url_invalid url ;
-      let host = String.sub url 1 (host_end - 1) in
-      let port =
-        String.sub url (host_end + 2) (String.length url - host_end - 2)
-      in
-      (host, int_of_string port)
-    ) else
-      match
-        Xapi_stdext_std.Xstringext.String.split_f (fun a -> a = ':') url
-      with
-      | [host; port] ->
-          (host, int_of_string port)
-      | _ ->
-          raise_url_invalid url
-  with _ -> raise_url_invalid url
+  let uri = Uri.of_string ("//" ^ url) in
+  match (Uri.host uri, Uri.port uri) with
+  | None, _ | _, None ->
+      raise_url_invalid url
+  | Some host, Some port ->
+      (host, port)
 
 let wlb_host_port ~__context =
   let pool = Helpers.get_pool ~__context in
diff --git a/ocaml/xapi/xapi_globs.ml b/ocaml/xapi/xapi_globs.ml
index 38700758b0b..8a062edbf29 100644
--- a/ocaml/xapi/xapi_globs.ml
+++ b/ocaml/xapi/xapi_globs.ml
@@ -1364,12 +1364,12 @@ let citrix_patch_key =
 
 let trusted_patch_key = ref citrix_patch_key
 
+let fields_of = Astring.(String.fields ~empty:false ~is_sep:Char.Ascii.is_white)
+
 let gen_list_option name desc of_string string_of opt =
   let parse s =
     opt := [] ;
-    try
-      Xapi_stdext_std.Xstringext.String.(split_f isspace s)
-      |> List.iter (fun x -> opt := of_string x :: !opt)
+    try fields_of s |> List.iter (fun x -> opt := of_string x :: !opt)
     with e ->
       D.error "Unable to parse %s=%s (expected space-separated list) error: %s"
         name s (Printexc.to_string e)
diff --git a/ocaml/xapi/xapi_host_crashdump.ml b/ocaml/xapi/xapi_host_crashdump.ml
index b7e9eedd74e..f9c66de62c8 100644
--- a/ocaml/xapi/xapi_host_crashdump.ml
+++ b/ocaml/xapi/xapi_host_crashdump.ml
@@ -16,7 +16,6 @@
 *)
 
 module Listext = Xapi_stdext_std.Listext
-module Xstringext = Xapi_stdext_std.Xstringext
 module Date = Clock.Date
 open Xapi_stdext_pervasives.Pervasiveext
 open Xapi_support
@@ -50,6 +49,8 @@ let delete_crashdump_dir filename =
       (ExnHelper.string_of_exn e) ;
     raise e
 
+let fields_of = Astring.(String.fields ~empty:false ~is_sep:Char.Ascii.is_white)
+
 (* Called once on host boot to resync the crash directory with the database *)
 let resynchronise ~__context ~host =
   debug "Xapi_host_crashdump.resynchronise" ;
@@ -103,9 +104,7 @@ let resynchronise ~__context ~host =
       debug "Adding record corresponding to new crashdump %s" filename ;
       let cmd = Printf.sprintf "%s --bytes -s %s/%s" du crash_dir filename in
       let size =
-        match
-          Xstringext.String.(split_f isspace (Helpers.get_process_output cmd))
-        with
+        match fields_of (Helpers.get_process_output cmd) with
         | size :: _ ->
             Int64.of_string size
         | _ ->
diff --git a/ocaml/xapi/xapi_pif.ml b/ocaml/xapi/xapi_pif.ml
index 0e730bda514..ccebf243816 100644
--- a/ocaml/xapi/xapi_pif.ml
+++ b/ocaml/xapi/xapi_pif.ml
@@ -19,7 +19,6 @@ module L = Debug.Make (struct let name = "license" end)
 
 open Xapi_database.Db_filter_types
 module Listext = Xapi_stdext_std.Listext.List
-module Stringext = Xapi_stdext_std.Xstringext.String
 module Date = Clock.Date
 open Network
 
@@ -709,6 +708,8 @@ let forget ~__context ~self =
 
 let scan_m = Mutex.create ()
 
+let fields_of = Astring.(String.fields ~empty:false ~is_sep:Char.Ascii.is_white)
+
 let scan ~__context ~host =
   let dbg = Context.string_of_task __context in
   refresh_all ~__context ~host ;
@@ -724,9 +725,9 @@ let scan ~__context ~host =
             debug "No boot from SAN interface found" ;
             ([], [])
         | m :: u :: _ ->
-            Stringext.(split_f isspace m, split_f isspace u)
+            (fields_of m, fields_of u)
         | m :: _ ->
-            Stringext.(split_f isspace m, [])
+            (fields_of m, [])
       with e ->
         warn "Error when executing script %s: %s; ignoring"
           !Xapi_globs.non_managed_pifs
diff --git a/ocaml/xapi/xha_interface.ml b/ocaml/xapi/xha_interface.ml
index a42107a63a6..dee90350575 100644
--- a/ocaml/xapi/xha_interface.ml
+++ b/ocaml/xapi/xha_interface.ml
@@ -349,9 +349,10 @@ module LiveSetInformation = struct
             | Some u ->
                 u
           in
-          let set f x =
-            List.map f Xapi_stdext_std.Xstringext.String.(split_f isspace x)
+          let fields_of =
+            Astring.(String.fields ~empty:false ~is_sep:Char.Ascii.is_white)
           in
+          let set f x = List.map f (fields_of x) in
           Some
             {
               id= uuid (find "HostID")

From aebedca1bd722bfe1a6855ab28c7b50e4255f06e Mon Sep 17 00:00:00 2001
From: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Date: Wed, 22 May 2024 10:48:06 +0100
Subject: [PATCH 8/8] xapi-stdext-std: change String.replace to replace
 characters

The few users that needed to replace strings, have been replaced with Astring's
cuts, as most of them were already segmenting strings, or they are run in very
specific, infrequent codepaths for efficiency to not matter.

Others have been replaced by Astring's filter as they were removing characters,
and the rest have been converted to the new String.replace.

map_unlikely can be removed from the interface and only have String.replaced
and String.replace

Signed-off-by: Pau Ruiz Safont <pau.ruizsafont@cloud.com>
Signed-off-by: Pau Ruiz Safont <pau.safont@vates.tech>
---
 ocaml/idl/ocaml_backend/gen_rbac.ml           |  2 +-
 .../lib/xapi-stdext-std/xstringext.ml         | 45 +++----------------
 .../lib/xapi-stdext-std/xstringext.mli        | 10 ++---
 ocaml/rrd2csv/src/rrd2csv.ml                  |  9 +---
 ocaml/xapi/audit_log.ml                       |  8 +---
 ocaml/xapi/extauth_plugin_ADpbis.ml           | 17 ++++---
 ocaml/xapi/pciops.ml                          |  3 +-
 ocaml/xapi/pvs_proxy_control.ml               |  4 +-
 ocaml/xapi/rbac_audit.ml                      |  4 +-
 ocaml/xapi/storage_mux.ml                     |  3 +-
 10 files changed, 32 insertions(+), 73 deletions(-)

diff --git a/ocaml/idl/ocaml_backend/gen_rbac.ml b/ocaml/idl/ocaml_backend/gen_rbac.ml
index 6934d691a3f..ad17e10db5f 100644
--- a/ocaml/idl/ocaml_backend/gen_rbac.ml
+++ b/ocaml/idl/ocaml_backend/gen_rbac.ml
@@ -72,7 +72,7 @@ let permission_description = "A basic permission"
 let permission_name wire_name =
   let s1 = replace_char (Printf.sprintf "permission_%s" wire_name) '.' '_' in
   let s2 = replace_char s1 '/' '_' in
-  let s3 = Xapi_stdext_std.Xstringext.String.replace "*" "WILDCHAR" s2 in
+  let s3 = Xapi_stdext_std.Xstringext.String.replace '*' ~by:"WILDCHAR" s2 in
   replace_char s3 ':' '_'
 
 let permission_index = ref 0
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
index 1c205b31faa..854245b9b6d 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml
@@ -32,46 +32,6 @@ module String = struct
     else
       s
 
-  (** find all occurences of needle in haystack and return all their respective index *)
-  let find_all needle haystack =
-    let m = String.length needle and n = String.length haystack in
-    if m > n then
-      []
-    else
-      let i = ref 0 and found = ref [] in
-      while !i < n - m + 1 do
-        if String.sub haystack !i m = needle then (
-          found := !i :: !found ;
-          i := !i + m
-        ) else
-          incr i
-      done ;
-      List.rev !found
-
-  (* replace all @f substring in @s by @t *)
-  let replace f t s =
-    let indexes = find_all f s in
-    let n = List.length indexes in
-    if n > 0 then (
-      let len_f = String.length f and len_t = String.length t in
-      let new_len = String.length s + (n * len_t) - (n * len_f) in
-      let new_b = Bytes.make new_len '\000' in
-      let orig_offset = ref 0 and dest_offset = ref 0 in
-      List.iter
-        (fun h ->
-          let len = h - !orig_offset in
-          Bytes.blit_string s !orig_offset new_b !dest_offset len ;
-          Bytes.blit_string t 0 new_b (!dest_offset + len) len_t ;
-          orig_offset := !orig_offset + len + len_f ;
-          dest_offset := !dest_offset + len + len_t
-        )
-        indexes ;
-      Bytes.blit_string s !orig_offset new_b !dest_offset
-        (String.length s - !orig_offset) ;
-      Bytes.unsafe_to_string new_b
-    ) else
-      s
-
   let map_unlikely s f =
     let changed = ref false in
     let m = ref 0 in
@@ -92,5 +52,10 @@ module String = struct
     ) else
       s
 
+  let replace char ~by s =
+    let replaceable = Stdlib.Char.equal char in
+    let get_replacement c = if replaceable c then Some by else None in
+    map_unlikely s get_replacement
+
   let replaced ~replace s = map_unlikely s replace
 end
diff --git a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
index e2ba23e0139..62a1053d883 100644
--- a/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
+++ b/ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli
@@ -17,18 +17,16 @@ module String : sig
       and when it returns [Some rep] the character is replaced with [rep] in
       the resulting string *)
 
+  val replace : char -> by:string -> string -> string
+  (** [replace ch ~by s] replaces all the occurrences of [ch] in [s] by [~by]
+    *)
+
   val split : limit:int -> char -> string -> string list
   (** split a string on a single char *)
 
   val rtrim : string -> string
   (** FIXME document me|remove me if similar to strip *)
 
-  val replace : string -> string -> string -> string
-  (** replace all [f] substring in [s] by [t] *)
-
-  val map_unlikely : string -> (char -> string option) -> string
-  (** map a string trying to fill the buffer by chunk *)
-
   val sub_to_end : string -> int -> string
   (** a substring from the specified position to the end of the string *)
 end
diff --git a/ocaml/rrd2csv/src/rrd2csv.ml b/ocaml/rrd2csv/src/rrd2csv.ml
index 1cfadb61983..bb57fbbb8d3 100644
--- a/ocaml/rrd2csv/src/rrd2csv.ml
+++ b/ocaml/rrd2csv/src/rrd2csv.ml
@@ -185,14 +185,7 @@ module Ds_selector = struct
   let escape_metric s =
     let quote s = Printf.sprintf "\"%s\"" s in
     if String.contains s '"' then
-      quote
-        (Xstringext.String.map_unlikely s (function
-          | '\"' ->
-              Some "\"\""
-          | _ ->
-              None
-          )
-          )
+      quote (Xstringext.String.replace '"' ~by:{|""|} s)
     else if String.contains s ',' || String.contains s '\n' then
       quote s
     else
diff --git a/ocaml/xapi/audit_log.ml b/ocaml/xapi/audit_log.ml
index 0563b2c4fe3..473df72f39e 100644
--- a/ocaml/xapi/audit_log.ml
+++ b/ocaml/xapi/audit_log.ml
@@ -102,12 +102,8 @@ let transfer_all_audit_files fd_out ?filter since =
   atransfer_try_gz ""
 
 (* map the ISO8601 timestamp format into the one in our logs *)
-let log_timestamp_of_iso8601 iso8601_timestamp =
-  let module Xstringext = Xapi_stdext_std.Xstringext in
-  let step1 = iso8601_timestamp in
-  let step2 = Xstringext.String.replace "-" "" step1 in
-  let step3 = Xstringext.String.replace "Z" "" step2 in
-  step3
+let log_timestamp_of_iso8601 iso8601 =
+  Astring.String.filter (function '-' | 'Z' -> false | _ -> true) iso8601
 
 (*
  Assume that RBAC access for the session_id already verified by xapi_http.ml
diff --git a/ocaml/xapi/extauth_plugin_ADpbis.ml b/ocaml/xapi/extauth_plugin_ADpbis.ml
index dac47414b33..b57b2c91cae 100644
--- a/ocaml/xapi/extauth_plugin_ADpbis.ml
+++ b/ocaml/xapi/extauth_plugin_ADpbis.ml
@@ -132,9 +132,11 @@ let match_error_tag (lines : string list) =
 let extract_sid_from_group_list group_list =
   List.map
     (fun (_, v) ->
-      let v = Stringext.replace ")" "" v in
-      let v = Stringext.replace "sid =" "|" v in
-      let vs = Astring.String.cuts ~empty:false ~sep:"|" v in
+      let vs =
+        Astring.String.filter (function ')' -> false | _ -> true) v
+        |> Astring.String.cuts ~empty:false ~sep:"sid ="
+        |> List.concat_map (Astring.String.cuts ~empty:false ~sep:"|")
+      in
       let sid = String.trim (List.nth vs 1) in
       debug "extract_sid_from_group_list get sid=[%s]" sid ;
       sid
@@ -167,7 +169,8 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
     Locking_helpers.Named_mutex.create "IS_SERVER_AVAILABLE"
 
   let splitlines s =
-    Astring.String.cuts ~empty:false ~sep:"\n" (Stringext.replace "#012" "\n" s)
+    Astring.String.cuts ~empty:false ~sep:"#012" s
+    |> List.concat_map (Astring.String.cuts ~empty:false ~sep:"\n")
 
   let pbis_common_with_password (password : string) (pbis_cmd : string)
       (pbis_args : string list) =
@@ -349,7 +352,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
         if !exited_code <> 0 then (
           error "execute '%s': exit_code=[%d] output=[%s]" debug_cmd
             !exited_code
-            (Stringext.replace "\n" ";" !output) ;
+            (Stringext.replace '\n' ~by:";" !output) ;
           let split_to_words s =
             Astring.String.fields ~empty:false ~is_sep:is_word_sep s
           in
@@ -1115,8 +1118,8 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
         in
         debug "execute %s: stdout=[%s],stderr=[%s]"
           pbis_force_domain_leave_script
-          (Stringext.replace "\n" ";" output)
-          (Stringext.replace "\n" ";" stderr)
+          (Stringext.replace '\n' ~by:";" output)
+          (Stringext.replace '\n' ~by:";" stderr)
       with e ->
         debug "exception executing %s: %s" pbis_force_domain_leave_script
           (ExnHelper.string_of_exn e)
diff --git a/ocaml/xapi/pciops.ml b/ocaml/xapi/pciops.ml
index 2126185474e..46cfdf377cc 100644
--- a/ocaml/xapi/pciops.ml
+++ b/ocaml/xapi/pciops.ml
@@ -126,7 +126,8 @@ let _unhide_pci ~__context pci =
       Printf.sprintf "(%s)" (Db.PCI.get_pci_id ~__context ~self:pci)
     in
     let new_value =
-      Xapi_stdext_std.Xstringext.String.replace bdf_paren "" raw_value
+      Astring.String.cuts ~empty:false ~sep:bdf_paren raw_value
+      |> String.concat ""
     in
     let cmd =
       match new_value with
diff --git a/ocaml/xapi/pvs_proxy_control.ml b/ocaml/xapi/pvs_proxy_control.ml
index 8597166fe7b..8a64cb2c051 100644
--- a/ocaml/xapi/pvs_proxy_control.ml
+++ b/ocaml/xapi/pvs_proxy_control.ml
@@ -21,7 +21,9 @@ open D
 let proxy_port_name vif =
   (* Interface names in Linux are at most 15 characters. We derive a
      name from the MAC address to ensure uniqueness, and make it fit. *)
-  let mac = Xapi_stdext_std.Xstringext.String.replace ":" "" vif.API.vIF_MAC in
+  let mac =
+    Astring.String.filter (function ':' -> false | _ -> true) vif.API.vIF_MAC
+  in
   Printf.sprintf "pvs%s" mac
 
 (** [proxies] returns all currently attached proxies *)
diff --git a/ocaml/xapi/rbac_audit.ml b/ocaml/xapi/rbac_audit.ml
index d0f94f6775b..7f86ba31030 100644
--- a/ocaml/xapi/rbac_audit.ml
+++ b/ocaml/xapi/rbac_audit.ml
@@ -453,9 +453,9 @@ let audit_line_of __context session_id allowed_denied ok_error result_error
          ?sexpr_of_args action permission
       )
   in
-  let line = Xapi_stdext_std.Xstringext.String.replace "\n" " " _line in
+  let line = Xapi_stdext_std.Xstringext.String.replace '\n' ~by:" " _line in
   (* no \n in line *)
-  let line = Xapi_stdext_std.Xstringext.String.replace "\r" " " line in
+  let line = Xapi_stdext_std.Xstringext.String.replace '\r' ~by:" " line in
   (* no \r in line *)
   let audit_line = append_line "%s" line in
   (*D.debug "line=%s, audit_line=%s" line audit_line;*)
diff --git a/ocaml/xapi/storage_mux.ml b/ocaml/xapi/storage_mux.ml
index ac8b0680f43..f2091c896d0 100644
--- a/ocaml/xapi/storage_mux.ml
+++ b/ocaml/xapi/storage_mux.ml
@@ -97,7 +97,8 @@ module Mux = struct
 
     let m = Mutex.create ()
 
-    let filename_of dp = Xapi_stdext_std.Xstringext.String.replace "/" "-" dp
+    let filename_of dp =
+      Xapi_stdext_std.Xstringext.String.replace '/' ~by:"-" dp
 
     let write dp info =
       let filename = filename_of dp in