Rewrite virt-resize in OCaml.

[libguestfs.git] / resize / utils.ml

diff --git a/resize/utils.ml b/resize/utils.ml
new file mode 100644 (file)
index 0000000..3851975
--- /dev/null
+++ b/resize/utils.ml
@@ -0,0 +1,154 @@
+(* virt-resize
+ * Copyright (C) 2010-2011 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+open Printf
+
+module G = Guestfs
+
+let ( +^ ) = Int64.add
+let ( -^ ) = Int64.sub
+let ( *^ ) = Int64.mul
+let ( /^ ) = Int64.div
+let ( &^ ) = Int64.logand
+let ( ~^ ) = Int64.lognot
+
+let output_spaces chan n = for i = 0 to n-1 do output_char chan ' ' done
+
+let wrap ?(chan = stdout) ?(hanging = 0) str =
+  let rec _wrap col str =
+    let n = String.length str in
+    let i = try String.index str ' ' with Not_found -> n in
+    let col =
+      if col+i >= 72 then (
+        output_char chan '\n';
+        output_spaces chan hanging;
+        i+hanging+1
+      ) else col+i+1 in
+    output_string chan (String.sub str 0 i);
+    if i < n then (
+      output_char chan ' ';
+      _wrap col (String.sub str (i+1) (n-(i+1)))
+    )
+  in
+  _wrap 0 str
+
+let error fs =
+  let display str =
+    wrap ~chan:stderr ("virt-resize: error: " ^ str);
+    prerr_newline ();
+    prerr_newline ();
+    wrap ~chan:stderr
+      "If reporting bugs, run virt-resize with the '-d' option and include the complete output.";
+    prerr_newline ();
+    exit 1
+  in
+  ksprintf display fs
+
+(* The reverse of device name translation, see
+ * BLOCK DEVICE NAMING in guestfs(3).
+ *)
+let canonicalize dev =
+  if String.length dev >= 8 &&
+    dev.[0] = '/' && dev.[1] = 'd' && dev.[2] = 'e' && dev.[3] = 'v' &&
+    dev.[4] = '/' && (dev.[5] = 'h' || dev.[5] = 'v') && dev.[6] = 'd' then (
+      let dev = String.copy dev in
+      dev.[5] <- 's';
+      dev
+    )
+  else
+    dev
+
+let feature_available (g : Guestfs.guestfs) names =
+  try g#available names; true
+  with G.Error _ -> false
+
+(* Parse the size field from --resize and --resize-force options. *)
+let parse_size =
+  let const_re = Pcre.regexp "^([.\\d]+)([bKMG])$"
+  and plus_const_re = Pcre.regexp "^\\+([.\\d]+)([bKMG])$"
+  and minus_const_re = Pcre.regexp "^-([.\\d]+)([bKMG])$"
+  and percent_re = Pcre.regexp "^([.\\d]+)%$"
+  and plus_percent_re = Pcre.regexp "^\\+([.\\d]+)%$"
+  and minus_percent_re = Pcre.regexp "^-([.\\d]+)%$"
+  in
+  fun oldsize field ->
+    let subs = ref None in
+    let matches rex =
+      try subs := Some (Pcre.exec ~rex field); true
+      with Not_found -> false
+    in
+    let sub i =
+      match !subs with None -> assert false
+      | Some subs -> Pcre.get_substring subs i
+    in
+    let size_scaled f = function
+      | "b" -> Int64.of_float f
+      | "K" -> Int64.of_float (f *. 1024.)
+      | "M" -> Int64.of_float (f *. 1024. *. 1024.)
+      | "G" -> Int64.of_float (f *. 1024. *. 1024. *. 1024.)
+      | _ -> assert false
+    in
+
+    if matches const_re then (
+      size_scaled (float_of_string (sub 1)) (sub 2)
+    )
+    else if matches plus_const_re then (
+      let incr = size_scaled (float_of_string (sub 1)) (sub 2) in
+      oldsize +^ incr
+    )
+    else if matches minus_const_re then (
+      let incr = size_scaled (float_of_string (sub 1)) (sub 2) in
+      oldsize -^ incr
+    )
+    else if matches percent_re then (
+      let percent = Int64.of_float (10. *. float_of_string (sub 1)) in
+      oldsize *^ percent /^ 1000L
+    )
+    else if matches plus_percent_re then (
+      let percent = Int64.of_float (10. *. float_of_string (sub 1)) in
+      oldsize +^ oldsize *^ percent /^ 1000L
+    )
+    else if matches minus_percent_re then (
+      let percent = Int64.of_float (10. *. float_of_string (sub 1)) in
+      oldsize -^ oldsize *^ percent /^ 1000L
+    )
+    else
+      error "virt-resize: %s: cannot parse size field" field
+
+let human_size i =
+  let sign, i = if i < 0L then "-", Int64.neg i else "", i in
+
+  if i < 1024L then
+    sprintf "%s%Ld" sign i
+  else (
+    let f = Int64.to_float i /. 1024. in
+    let i = i /^ 1024L in
+    if i < 1024L then
+      sprintf "%s%.1fK" sign f
+    else (
+      let f = Int64.to_float i /. 1024. in
+      let i = i /^ 1024L in
+      if i < 1024L then
+        sprintf "%s%.1fM" sign f
+      else (
+        let f = Int64.to_float i /. 1024. in
+        (*let i = i /^ 1024L in*)
+        sprintf "%s%.1fG" sign f
+      )
+    )
+  )