Replace startswith and endswith with stdlib calls

Drops `startswith` and `endswith` from `String` (within
`xapi-stdext/xapi-stdext-std`).

These functions were introduced in OCaml 4.13:

```
String.starts_with : prefix:string -> string -> bool
```

Usage sites are adapted to supply the relevant labelled argument in each
case, e.g. ~prefix:"foo".

Signed-off-by: Colin James <[email protected]>

Author: Colin James

ocaml/database/parse_db_conf.ml

@@ -168,7 +168,7 @@ let parse_db_conf s =
     let connections : db_connection list ref = ref [] in
     while !lines <> [] do
       let line = List.hd !lines in
-      if String.startswith "[" line then
+      if String.starts_with ~prefix:"[" line then
         connections := read_block () :: !connections
       else
         consume_line ()

ocaml/idl/datamodel_utils.ml

@@ -183,7 +183,7 @@ let find_self_parameter (msg : message) =
         )
 
 let plural name =
-  if Xstringext.String.endswith "metrics" name then
+  if String.ends_with ~suffix:"metrics" name then
     name ^ " instances"
   else
     name ^ "s"

ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.ml

@@ -39,16 +39,6 @@ module String = struct
     done ;
     !accu
 
-  (** True if string 'x' ends with suffix 'suffix' *)
-  let endswith suffix x =
-    let x_l = String.length x and suffix_l = String.length suffix in
-    suffix_l <= x_l && String.sub x (x_l - suffix_l) suffix_l = suffix
-
-  (** True if string 'x' starts with prefix 'prefix' *)
-  let startswith prefix x =
-    let x_l = String.length x and prefix_l = String.length prefix in
-    prefix_l <= x_l && String.sub x 0 prefix_l = prefix
-
   (** Returns true for whitespace characters, false otherwise *)
   let isspace = function ' ' | '\n' | '\r' | '\t' -> true | _ -> false
 

ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext.mli

@@ -29,12 +29,6 @@ module String : sig
   val fold_right : (char -> 'a -> 'a) -> string -> 'a -> 'a
   (** Iterate over the characters in a string in reverse order. *)
 
-  val endswith : string -> string -> bool
-  (** True if string 'x' ends with suffix 'suffix' *)
-
-  val startswith : string -> string -> bool
-  (** True if string 'x' starts with prefix 'prefix' *)
-
   val isspace : char -> bool
   (** True if the character is whitespace *)
 

ocaml/libs/xapi-stdext/lib/xapi-stdext-std/xstringext_test.ml

@@ -127,44 +127,6 @@ let test_has_substr =
   in
   ("has_substr", List.map test spec)
 
-let test_startswith =
-  let spec =
-    [
-      ("", "", true)
-    ; ("", "foo bar", true)
-    ; ("foofo", "foof", false)
-    ; ("foof", "foof", true)
-    ; ("f", "foof", true)
-    ; ("fo", "foof", true)
-    ; ("of", "foof", false)
-    ; ("ff", "foof", false)
-    ]
-  in
-  let test (contained, container, expected) =
-    let name = Printf.sprintf {|"%s" starts with "%s"|} container contained in
-    test_boolean (XString.startswith contained) (name, container, expected)
-  in
-  ("startswith", List.map test spec)
-
-let test_endswith =
-  let spec =
-    [
-      ("", "", true)
-    ; ("", "foo bar", true)
-    ; ("ofoof", "foof", false)
-    ; ("foof", "foof", true)
-    ; ("f", "foof", true)
-    ; ("fo", "foof", false)
-    ; ("of", "foof", true)
-    ; ("ff", "foof", false)
-    ]
-  in
-  let test (contained, container, expected) =
-    let name = Printf.sprintf {|"%s" ends with "%s"|} container contained in
-    test_boolean (XString.endswith contained) (name, container, expected)
-  in
-  ("endswith", List.map test spec)
-
 let test_rtrim =
   let spec =
     [
@@ -187,12 +149,4 @@ let test_rtrim =
 
 let () =
   Alcotest.run "Xstringext"
-    [
-      test_rev_map
-    ; test_split
-    ; test_split_f
-    ; test_has_substr
-    ; test_startswith
-    ; test_endswith
-    ; test_rtrim
-    ]
+    [test_rev_map; test_split; test_split_f; test_has_substr; test_rtrim]

ocaml/mpathalert/mpathalert.ml

@@ -95,7 +95,7 @@ let rec retry_with_session f rpc x =
     retry_with_session f rpc x
 
 let keep_mpath =
-  List.filter (fun (key, _) -> Xstringext.String.startswith "mpath-" key)
+  List.filter (fun (key, _) -> String.starts_with ~prefix:"mpath-" key)
 
 let create_alert ~host_uuid_string ~host_name ~pbd_uuid_string key value
     timestamp scsi_id =

ocaml/quicktest/qt.ml

@@ -122,7 +122,7 @@ module VM = struct
       match
         List.filter
           (fun self ->
-            Xapi_stdext_std.Xstringext.String.startswith startswith
+            String.starts_with ~prefix:startswith
               (Client.Client.VM.get_name_label ~rpc ~session_id ~self)
             && Client.Client.VM.get_is_a_template ~rpc ~session_id ~self
           )

ocaml/rrd2csv/src/rrd2csv.ml

@@ -282,7 +282,7 @@ module Ds_selector = struct
      match the non-null fields of f *)
   let filter11 f d =
     true
-    && (Xstringext.String.startswith f.metric d.metric || f.metric = "")
+    && (String.starts_with ~prefix:f.metric d.metric || f.metric = "")
     && (f.cf = d.cf || f.cf = None)
     && ( match (f.owner, d.owner) with
        | None, _ ->
@@ -601,7 +601,7 @@ let print_last session_id data_sources =
 let filter_ds_that_starts_with_name dss name =
   List.fold_left
     (fun acc ds ->
-      if Xstringext.String.startswith name ds.Ds_selector.metric then
+      if String.starts_with ~prefix:name ds.Ds_selector.metric then
         ds :: acc
       else
         acc

ocaml/xapi/extauth_plugin_ADpbis.ml

@@ -363,7 +363,7 @@ module AuthADlw : Auth_signature.AUTH_MODULE = struct
           let errcode =
             List.hd
               (List.filter
-                 (fun w -> String.startswith "LW_ERROR_" w)
+                 (fun w -> String.starts_with ~prefix:"LW_ERROR_" w)
                  (split_to_words errcodeline)
               )
           in

ocaml/xapi/fileserver.ml

@@ -78,7 +78,7 @@ let send_file (uri_base : string) (dir : string) (req : Request.t)
       let file_path =
         Xapi_stdext_unix.Unixext.resolve_dot_and_dotdot file_path
       in
-      if not (String.startswith dir file_path) then (
+      if not (String.starts_with ~prefix:dir file_path) then (
         debug "Rejecting request for file: %s (outside of directory %s)"
           file_path dir ;
         Http_svr.response_forbidden ~req s

ocaml/xapi/gpg.ml

@@ -28,7 +28,7 @@ exception InvalidSignature
 let parse_gpg_status status_data =
   let lines = String.split '\n' status_data in
   let status_contains substr =
-    List.exists (fun s -> String.startswith substr s) lines
+    List.exists (fun s -> String.starts_with ~prefix:substr s) lines
   in
   if
     not
@@ -40,7 +40,7 @@ let parse_gpg_status status_data =
   let validsig = "[GNUPG:] VALIDSIG" in
   if status_contains validsig then
     let validsigline =
-      List.find (fun s -> String.startswith validsig s) lines
+      List.find (fun s -> String.starts_with ~prefix:validsig s) lines
     in
     match String.split ' ' validsigline with
     | _ :: _ :: fingerprint :: _ ->

ocaml/xapi/import.ml

@@ -189,7 +189,7 @@ let assert_can_restore_backup ~__context rpc session_id (x : header) =
   let get_vm_uuid_of_snap s =
     let snapshot_of = Ref.string_of s.API.vM_snapshot_of in
     try
-      if Xstringext.String.startswith "Ref:" snapshot_of then
+      if String.starts_with ~prefix:"Ref:" snapshot_of then
         (* This should be a snapshot in the archive *)
         let v =
           List.find
@@ -198,7 +198,7 @@ let assert_can_restore_backup ~__context rpc session_id (x : header) =
         in
         let v = get_vm_record v.snapshot in
         Some v.API.vM_uuid
-      else if Xstringext.String.startswith Ref.ref_prefix snapshot_of then
+      else if String.starts_with ~prefix:Ref.ref_prefix snapshot_of then
         (* This should be a snapshot in a live system *)
         if Db.is_valid_ref __context s.API.vM_snapshot_of then
           Some (Db.VM.get_uuid ~__context ~self:s.API.vM_snapshot_of)
@@ -2313,9 +2313,7 @@ let read_map_params name params =
   (* include ':' *)
   let filter_params =
     List.filter
-      (fun (p, _) ->
-        Xstringext.String.startswith name p && String.length p > len
-      )
+      (fun (p, _) -> String.starts_with ~prefix:name p && String.length p > len)
       params
   in
   List.map

ocaml/xapi/nm.ml

@@ -215,7 +215,7 @@ let create_bond ~__context bond mtu persistent =
       let overrides =
         List.filter_map
           (fun (k, v) ->
-            if String.startswith "bond-" k then
+            if String.starts_with ~prefix:"bond-" k then
               Some (String.sub_to_end k 5, v)
             else
               None

ocaml/xapi/workload_balancing.ml

@@ -233,7 +233,7 @@ let wlb_request host meth body encoded_auth =
 let filtered_headers headers =
   List.map
     (fun s ->
-      if String.startswith "Authorization:" s then
+      if String.starts_with ~prefix:"Authorization:" s then
         "Authorization: Basic <password>"
       else
         s

ocaml/xapi/xapi_network.ml

@@ -252,7 +252,7 @@ let create ~__context ~name_label ~name_description ~mTU ~other_config ~bridge
             (not is_internal_session)
             && (String.length bridge > 15
                || List.exists
-                    (fun s -> String.startswith s bridge)
+                    (fun s -> String.starts_with ~prefix:s bridge)
                     bridge_blacklist
                )
           then

ocaml/xapi/xapi_pif.ml

@@ -132,7 +132,7 @@ let refresh_all ~__context ~host =
   List.iter (fun self -> refresh_internal ~__context ~self) pifs
 
 let bridge_naming_convention (device : string) =
-  if String.startswith "eth" device then
+  if String.starts_with ~prefix:"eth" device then
     "xenbr" ^ String.sub device 3 (String.length device - 3)
   else
     "br" ^ device

ocaml/xapi/xapi_pool.ml

@@ -2839,8 +2839,8 @@ let enable_external_auth ~__context ~pool:_ ~config ~service_name ~auth_type =
                          (Api_errors.auth_unknown_type, [msg_of_e])
                       )
                 | err_of_e
-                  when Xstringext.String.startswith
-                         Api_errors.auth_enable_failed err_of_e ->
+                  when String.starts_with ~prefix:Api_errors.auth_enable_failed
+                         err_of_e ->
                     raise
                       (Api_errors.Server_error
                          ( Api_errors.pool_auth_prefix ^ err_of_e
@@ -2923,7 +2923,7 @@ let disable_external_auth ~__context ~pool:_ ~config =
             debug
               "Failed to disable the external authentication of at least one \
                host in the pool" ;
-            if Xstringext.String.startswith Api_errors.auth_disable_failed err
+            if String.starts_with ~prefix:Api_errors.auth_disable_failed err
             then (* tagged exception *)
               raise
                 (Api_errors.Server_error

ocaml/xapi/xapi_pool_update.ml

@@ -817,7 +817,7 @@ let pool_update_download_handler (req : Request.t) s _ =
   if host_uuid <> localhost_uuid then
     proxy_request req s host_uuid
   else if
-    (not (String.startswith !Xapi_globs.host_update_dir filepath))
+    (not (String.starts_with ~prefix:!Xapi_globs.host_update_dir filepath))
     || not (Sys.file_exists filepath)
   then (
     debug

ocaml/xapi/xapi_secret.ml

@@ -41,7 +41,7 @@ let clean_out_passwds ~__context strmap =
       Db.Secret.destroy ~__context ~self:s
     with _ -> ()
   in
-  let check_key (k, _) = String.endswith "password_secret" k in
+  let check_key (k, _) = String.ends_with ~suffix:"password_secret" k in
   let secrets = List.map snd (List.filter check_key strmap) in
   List.iter delete_secret secrets
 
@@ -55,7 +55,7 @@ let copy ~__context ~secret =
 (* Modify a ((string * string) list) by duplicating all the passwords found in
  * it *)
 let duplicate_passwds ~__context strmap =
-  let check_key k = String.endswith "password_secret" k in
+  let check_key k = String.ends_with ~suffix:"password_secret" k in
   let possibly_duplicate (k, v) =
     if check_key k then
       let sr = Db.Secret.get_by_uuid ~__context ~uuid:v in
@@ -70,7 +70,7 @@ let duplicate_passwds ~__context strmap =
 
 let move_passwds_to_secrets ~__context strmap =
   let maybe_move (k, value) =
-    if String.endswith "password" k then (
+    if String.ends_with ~suffix:"password" k then (
       let new_k = k ^ "_secret" in
       warn
         "Replacing deprecated %s with %s, please avoid using %s in \

ocaml/xapi/xapi_xenops.ml

@@ -1643,7 +1643,11 @@ module Xenopsd_metadata = struct
           (List.assoc Xapi_globs.persist_xenopsd_md oc)
         |> Xapi_stdext_unix.Unixext.resolve_dot_and_dotdot
       in
-      if not (String.startswith Xapi_globs.persist_xenopsd_md_root file_path)
+      if
+        not
+          (String.starts_with ~prefix:Xapi_globs.persist_xenopsd_md_root
+             file_path
+          )
       then
         warn "Not persisting xenopsd metadata to bad location: '%s'" file_path
       else (
@@ -1893,7 +1897,7 @@ let update_vm ~__context id =
             let results =
               List.filter_map
                 (fun (path, _) ->
-                  if String.startswith dir path then
+                  if String.starts_with ~prefix:dir path then
                     let rest =
                       String.sub path (String.length dir)
                         (String.length path - String.length dir)

ocaml/xe-cli/newcli.ml

@@ -118,7 +118,9 @@ let rec read_rest_of_headers ic =
       debug "read '%s'\n" r ;
       let hdr =
         List.find
-          (fun s -> String.startswith (s ^ ": ") (String.lowercase_ascii r))
+          (fun s ->
+            String.starts_with ~prefix:(s ^ ": ") (String.lowercase_ascii r)
+          )
           hdrs
       in
       let value = end_of_string r (String.length hdr + 2) in