[Xen-API] [PATCH] Adds functions "file_lines_{fold, iter}" to the Unixext module. These functions implement the standard "fold" and "iter" functions for all the lines in a file

[Jonathan Knowles <jonathan.knowles@xxxxxxxxxxxxx>]

# HG changeset patch
# User Jonathan Knowles <jonathan.knowles@xxxxxxxxxxxxx>
# Date 1258726936 0
# Node ID dd25a8923a9a5bc082d848e57b0e3eee34ad5e30
# Parent  4d0f0db47314e509928e05d578e9c2eb58d89e88
Adds functions "file_lines_{fold,iter}" to the Unixext module. These functions 
implement the standard "fold" and "iter" functions for all the lines in a file.

Signed-off-by: Jonathan Knowles <jonathan.knowles@xxxxxxxxxxxxx>

diff -r 4d0f0db47314 -r dd25a8923a9a stdext/unixext.ml
--- a/stdext/unixext.ml Tue Nov 17 10:55:17 2009 +0000
+++ b/stdext/unixext.ml Fri Nov 20 14:22:16 2009 +0000
@@ -85,18 +85,31 @@
                end
        | _ -> exit 0
 
-(** Run a function over every line in a file *)
-let readfile_line fn fname =
-       let fin = open_in fname in
+let file_lines_fold f start file_path =
+       let input = open_in file_path in
+       let rec fold accumulator =
+               let line =
+                       try Some (input_line input)
+                       with End_of_file -> None in
+               match line with
+                       | Some line -> fold (f accumulator line)
+                       | None -> accumulator in
+       finally
+               (fun () -> fold start)
+               (fun () -> close_in input)
+
+let file_lines_iter f file_path =
+       let input = open_in file_path in
        try
                while true do
-                       let line = input_line fin in
-                       fn line
-               done;
-               close_in fin;
+                       let line = input_line input in
+                       f line
+               done
        with
-       | End_of_file -> close_in fin
-       | exn -> close_in fin; raise exn
+               | End_of_file -> close_in input
+               | exn -> close_in input; raise exn
+
+let readfile_line = file_lines_iter
 
 (** open a file, and make sure the close is always done *)
 let with_file file mode perms f =
diff -r 4d0f0db47314 -r dd25a8923a9a stdext/unixext.mli
--- a/stdext/unixext.mli        Tue Nov 17 10:55:17 2009 +0000
+++ b/stdext/unixext.mli        Fri Nov 20 14:22:16 2009 +0000
@@ -11,6 +11,8 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Lesser General Public License for more details.
  *)
+(** A collection of extensions to the [Unix] module. *)
+
 external _exit : int -> unit = "unix_exit"
 val unlink_safe : string -> unit
 val mkdir_safe : string -> Unix.file_perm -> unit
@@ -20,6 +22,15 @@
 val daemonize : unit -> unit
 val with_file : string -> Unix.open_flag list -> Unix.file_perm -> 
(Unix.file_descr -> 'a) -> 'a
 val with_directory : string -> (Unix.dir_handle -> 'a) -> 'a
+
+(** Folds function [f] over every line in the file at [file_path] using the
+starting value [start]. *)
+val file_lines_fold : ('a -> string -> 'a) -> 'a -> string -> 'a
+
+(** Applies function [f] to every line in the file at [file_path]. *)
+val file_lines_iter : (string -> unit) -> string -> unit
+
+(** Alias for function [file_lines_iter]. *)
 val readfile_line : (string -> 'a) -> string -> unit
 val read_whole_file : int -> int -> Unix.file_descr -> string
 val read_whole_file_to_string : string -> string

Attachment: xen-api-libs.hg.patch
Description: Text Data

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