Reapply "Refactor Date implementation in VM."

samples/total/client/DateTimeUtils.dart

 // Copyright (c) 2011, 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.
 
 class DateUtils {
   static final int DAYS_FROM_1900_TO_1970 = 25569;
   static final int MILLISECONDS_PER_DAY = 86400000;
   static final int MILLISECONDS_PER_HOUR = 3600000;
   static Date _EPOCH;
 
@@ skipping 47 matching lines @@
     if (mmddyyyy.hasMatch(value)) {
       return true;
     }
     return false;
   }
 
   // Return the number of days between 1899-12-30 and the current time.
   static double now() {
     Date nowDate = new Date.now();
     int milliseconds = nowDate.difference(EPOCH).inMilliseconds;
-    milliseconds += MILLISECONDS_PER_HOUR; // FIXME - something is one hour behind
-    double days = milliseconds / MILLISECONDS_PER_DAY;
+    // We round the result to get rid of daylight saving differences.
+    double days = (milliseconds / MILLISECONDS_PER_DAY).round();
     return days;
   }
 
   // Parse a date and return the number of days between 1899-12-30 and the given date.
   // The acceptable formats are as described in the comments for isDate(String).
   static double parseDate(String value) {
     RegExp mmdd = const RegExp("^(\\d\\d?)[-/](\\d\\d?)\$");
     Match m = mmdd.firstMatch(value);
     if (m != null) {
       int month = _parseInt(m[1]);
       int day = _parseInt(m[2]);
       Date nowDate = new Date.now();
       int thisYear = nowDate.year;
       Date dateTime = new Date(thisYear, month, day, 0, 0, 0, 0);
       int milliseconds = dateTime.difference(EPOCH).inMilliseconds;
-      milliseconds += MILLISECONDS_PER_HOUR; // FIXME - something is one hour behind
-      double days = milliseconds / MILLISECONDS_PER_DAY;
+      // We round the result to get rid of daylight saving differences.
+      double days = (milliseconds / MILLISECONDS_PER_DAY).round();
       return days;
     }
 
     RegExp mmddyyyy = const RegExp("^(\\d\\d?)[-/](\\d\\d?)[-/](\\d\\d\\d?\\d?)\$");
     m = mmddyyyy.firstMatch(value);
     if (m != null) {
       int month = _parseInt(m[1]);
       int day = _parseInt(m[2]);
       int year = _parseInt(m[3]);
       // 0-50 ==> 2000-2050, 51-99 ==> 1951-1999
       if (year < 50) {
         year += 2000;
       } else if (year < 100) {
         year += 1900;
       }
       Date dateTime = new Date(year, month, day, 0, 0, 0, 0);
       int milliseconds = dateTime.difference(EPOCH).inMilliseconds;
-      milliseconds += MILLISECONDS_PER_HOUR; // FIXME - something is one hour behind
-      double days = milliseconds / MILLISECONDS_PER_DAY;
+      // We round the result to get rid of daylight saving differences.
+      double days = (milliseconds / MILLISECONDS_PER_DAY).round();
       return days;
     }
 
     return -1.0;
   }
 
   // Return the number of days between 1899-12-30 and the current time, truncated to
   // an integer.
   static double today() => now().floor();
 
   // Parse an integer, stripping leading zeros to avoid an octal parsing bug.
   static int _parseInt(String s) {
     while (s.length > 1 && s.charCodeAt(0) == StringUtils.ZERO) {
       s = s.substring(1, s.length);
     }
     return Math.parseInt(s);
   }
 }