gitk: Allow displaying time zones from author and commit dates timestamps

diff --git a/gitk b/gitk
index a4a8bd30ae17e5f5de77d5ed044822f0bccf2eaa..a40de31ce04d5842774455b284944768d4e832e3 100755 (executable)
--- a/gitk
+++ b/gitk
@@ -11580,7 +11580,29 @@ proc prefsok {} {
 proc formatdate {d} {
     global datetimeformat
     if {$d ne {}} {
-       set d [clock format [lindex $d 0] -format $datetimeformat]
+       # If $datetimeformat includes a timezone, display in the
+       # timezone of the argument.  Otherwise, display in local time.
+       if {[string match {*%[zZ]*} $datetimeformat]} {
+           if {[catch {set d [clock format [lindex $d 0] -timezone [lindex $d 1] -format $datetimeformat]}]} {
+               # Tcl < 8.5 does not support -timezone.  Emulate it by
+               # setting TZ (e.g. TZ=<-0430>+04:30).
+               global env
+               if {[info exists env(TZ)]} {
+                   set savedTZ $env(TZ)
+               }
+               set zone [lindex $d 1]
+               set sign [string map {+ - - +} [string index $zone 0]]
+               set env(TZ) <$zone>$sign[string range $zone 1 2]:[string range $zone 3 4]
+               set d [clock format [lindex $d 0] -format $datetimeformat]
+               if {[info exists savedTZ]} {
+                   set env(TZ) $savedTZ
+               } else {
+                   unset env(TZ)
+               }
+           }
+       } else {
+           set d [clock format [lindex $d 0] -format $datetimeformat]
+       }
     }
     return $d
 }