Add support for timezone offset and timezone name.

runtime/vm/os_macos.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/os.h"
 
 #include <errno.h>
 #include <limits.h>
 #include <mach/mach.h>
 #include <mach/clock.h>
@@ skipping 42 matching lines @@
   tm->tm_wday = -1;
   time_t seconds = mktime(tm);
   if ((seconds == -1) && (tm->tm_wday == -1)) {
     return false;
   }
   *seconds_result = seconds;
   return true;
 }
 
 
+bool OS::GetTimeZoneName(int64_t seconds_since_epoch,
+                         const char** name_result) {
+  tm decomposed;
+  bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
+  if (!succeeded) return false;
+  *name_result = decomposed.tm_zone;
+  return true;
+}
+
+
+bool OS::GetTimeZoneOffsetInSeconds(int64_t seconds_since_epoch,
+                                    int* offset_result) {
+  tm decomposed;
+  bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
+  if (!succeeded) return false;
+  // Even if the offset was 24 hours it would still easily fit into 32 bits.
+  *offset_result = static_cast<int>(decomposed.tm_gmtoff);
+  return true;
+}
+
+
 int64_t OS::GetCurrentTimeMillis() {
   return GetCurrentTimeMicros() / 1000;
 }
 
 
 int64_t OS::GetCurrentTimeMicros() {
   // gettimeofday has microsecond resolution.
   struct timeval tv;
   if (gettimeofday(&tv, NULL) < 0) {
     UNREACHABLE();
@@ skipping 101 matching lines @@
 void OS::Abort() {
   abort();
 }
 
 
 void OS::Exit(int code) {
   exit(code);
 }
 
 }  // namespace dart