Revert "Refactor Date implementation in VM."

runtime/vm/os_win.cc

Index: runtime/vm/os_win.cc
diff --git a/runtime/vm/os_win.cc b/runtime/vm/os_win.cc
index e0ff669ea715d19b74e184e224409386854021e3..778f9953d8c7bb7c11587b0a3d2761107dc19d30 100644
--- a/runtime/vm/os_win.cc
+++ b/runtime/vm/os_win.cc
@@ -10,8 +10,16 @@
 
 namespace dart {
 
+bool OS::GmTime(int64_t seconds_since_epoch, tm* tm_result) {
+  time_t seconds = static_cast<time_t>(seconds_since_epoch);
+  if (seconds != seconds_since_epoch) return false;
+  errno_t error_code = gmtime_s(tm_result, &seconds);
+  return error_code == 0;
+}
+
+
 // As a side-effect sets the globals _timezone, _daylight and _tzname.
-static bool LocalTime(int64_t seconds_since_epoch, tm* tm_result) {
+bool OS::LocalTime(int64_t seconds_since_epoch, tm* tm_result) {
   time_t seconds = static_cast<time_t>(seconds_since_epoch);
   if (seconds != seconds_since_epoch) return false;
   // localtime_s implicitly sets _timezone, _daylight and _tzname.
@@ -20,6 +28,34 @@ static bool LocalTime(int64_t seconds_since_epoch, tm* tm_result) {
 }
 
 
+bool OS::MkGmTime(tm* tm, int64_t* seconds_result) {
+  // Disable daylight saving.
+  tm->tm_isdst = 0;
+  // Set wday to an impossible day, so that we can catch bad input.
+  tm->tm_wday = -1;
+  time_t seconds = _mkgmtime(tm);
+  if ((seconds == -1) && (tm->tm_wday == -1)) {
+    return false;
+  }
+  *seconds_result = seconds;
+  return true;
+}
+
+
+bool OS::MkTime(tm* tm, int64_t* seconds_result) {
+  // Let the libc figure out if daylight saving is active.
+  tm->tm_isdst = -1;
+  // Set wday to an impossible day, so that we can catch bad input.
+  tm->tm_wday = -1;
+  time_t seconds = mktime(tm);
+  if ((seconds == -1) && (tm->tm_wday == -1)) {
+    return false;
+  }
+  *seconds_result = seconds;
+  return true;
+}
+
+
 static int GetDaylightSavingBiasInSeconds() {
   TIME_ZONE_INFORMATION zone_information;
   memset(&zone_information, 0, sizeof(zone_information));
@@ -31,41 +67,39 @@ static int GetDaylightSavingBiasInSeconds() {
   }
 }
 
-
-const char* OS::GetTimeZoneName(int64_t seconds_since_epoch) {
+bool OS::GetTimeZoneName(int64_t seconds_since_epoch,
+                         const char** name_result) {
   tm decomposed;
   // LocalTime will set _tzname.
   bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
-  ASSERT(succeeded);
+  if (!succeeded) return false;
   int inDaylightSavingsTime = decomposed.tm_isdst;
-  ASSERT(inDaylightSavingsTime == 0 || inDaylightSavingsTime == 1);
-  return _tzname[inDaylightSavingsTime];
+  if (inDaylightSavingsTime != 0 && inDaylightSavingsTime != 1) {
+    return false;
+  }
+  *name_result = _tzname[inDaylightSavingsTime];
+  return true;
 }
 
 
-int OS::GetTimeZoneOffsetInSeconds(int64_t seconds_since_epoch) {
+bool OS::GetTimeZoneOffsetInSeconds(int64_t seconds_since_epoch,
+                                    int* offset_result) {
   tm decomposed;
   // LocalTime will set _timezone.
   bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
-  ASSERT(succeeded);
+  if (!succeeded) return false;
   int inDaylightSavingsTime = decomposed.tm_isdst;
-  ASSERT(inDaylightSavingsTime == 0 || inDaylightSavingsTime == 1);
+  if (inDaylightSavingsTime != 0 && inDaylightSavingsTime != 1) {
+    return false;
+  }
   // Dart and Windows disagree on the sign of the bias.
-  int offset = static_cast<int>(-_timezone);
+  *offset_result = static_cast<int>(-_timezone);
   if (inDaylightSavingsTime == 1) {
     static int daylight_bias = GetDaylightSavingBiasInSeconds();
     // Subtract because windows and Dart disagree on the sign.
-    offset = offset - daylight_bias;
+    *offset_result = *offset_result - daylight_bias;
   }
-  return offset;
-}
-
-
-int OS::GetLocalTimeZoneAdjustmentInSeconds() {
-  // TODO(floitsch): avoid excessive calls to _tzset?
-  _tzset();
-  // Dart and Windows disagree on the sign of the bias.
-  return static_cast<int>(-_timezone);
+  return true;
 }