Fix --end-time option with absolute times.

Assume the user enters a local time, and convert it to UTC.

This also adds some clarifying comments to the relative time
code (but doesn't change that code).

Note that the obsolete Calendar1 code is *not* updated by this change.

diff --git a/virt-top/virt_top_calendar2.ml b/virt-top/virt_top_calendar2.ml
index cb0ebec..cc82eec 100755 (executable)
--- a/virt-top/virt_top_calendar2.ml
+++ b/virt-top/virt_top_calendar2.ml
@@ -38,18 +38,28 @@ fun time ->
          Calendar.Period.make 0 0 0 hh mm ss
        ) else                          (* +seconds *)
          Calendar.Period.second (int_of_string period) in
-      (* Add it as an offset from the current time. *)
+      (* Add it as an offset from the current time.
+       *
+       * Note that the default for the Calendar library is to return
+       * Calendar.now in the UTC time zone, which is in fact what we
+       * need below.
+       *)
       Calendar.add (Calendar.now ()) period
     ) else (
-      if String.contains time '-' then (* YYYY-MM-DD HH:MM:SS *)
-       Printer.CalendarPrinter.from_string time
-      else (                           (* HH:MM:SS *)
-       let time = Printer.TimePrinter.from_string time in
-       Calendar.create (Date.today ()) time
-      )
+      let cal =
+        if String.contains time '-' then (* YYYY-MM-DD HH:MM:SS *)
+         Printer.CalendarPrinter.from_string time
+        else (                          (* HH:MM:SS *)
+         let time = Printer.TimePrinter.from_string time in
+         Calendar.create (Date.today ()) time
+        ) in
+      (* Assume the user has entered a local time.  Convert it to
+       * UTC time zone which is what we need below.  (RHBZ#680344)
+       *)
+      Calendar.convert cal Time_Zone.Local Time_Zone.UTC
     ) in
 
-  eprintf "end time: %s\n" (Printer.CalendarPrinter.to_string cal);
+  eprintf "end time (UTC): %s\n" (Printer.CalendarPrinter.to_string cal);
 
   (* Convert to a time_t.  Note that we compare this against
    * Unix.gettimeofday in the main module, so this must be returned as