Revert "Refactor Date implementation in VM."

runtime/vm/os_linux.cc

Index: runtime/vm/os_linux.cc
diff --git a/runtime/vm/os_linux.cc b/runtime/vm/os_linux.cc
index e89b68f914b1262117fdb8c0f7026a0d816f1fd4..ff857cbe3519b799f551b6bb69bccfd665247a54 100644
--- a/runtime/vm/os_linux.cc
+++ b/runtime/vm/os_linux.cc
@@ -17,7 +17,15 @@
 
 namespace dart {
 
-static bool LocalTime(int64_t seconds_since_epoch, tm* tm_result) {
+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;
+  struct tm* error_code = gmtime_r(&seconds, tm_result);
+  return error_code != NULL;
+}
+
+
+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;
   struct tm* error_code = localtime_r(&seconds, tm_result);
@@ -25,29 +33,50 @@ static bool LocalTime(int64_t seconds_since_epoch, tm* tm_result) {
 }
 
 
-const char* OS::GetTimeZoneName(int64_t seconds_since_epoch) {
-  tm decomposed;
-  bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
-  ASSERT(succeeded);
-  return decomposed.tm_zone;
+bool OS::MkGmTime(tm* tm, int64_t* seconds_result) {
+  // Set wday to an impossible day, so that we can catch bad input.
+  tm->tm_wday = -1;
+  time_t seconds = timegm(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;
 }
 
 
-int OS::GetTimeZoneOffsetInSeconds(int64_t seconds_since_epoch) {
+bool OS::GetTimeZoneName(int64_t seconds_since_epoch,
+                         const char** name_result) {
   tm decomposed;
   bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
-  ASSERT(succeeded);
-  // Even if the offset was 24 hours it would still easily fit into 32 bits.
-  return static_cast<int>(decomposed.tm_gmtoff);
+  if (!succeeded) return false;
+  *name_result = decomposed.tm_zone;
+  return true;
 }
 
 
-int OS::GetLocalTimeZoneAdjustmentInSeconds() {
-  // TODO(floitsch): avoid excessive calls to tzset?
-  tzset();
+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.
-  // Note that Unix and Dart disagree on the sign.
-  return static_cast<int>(-timezone);
+  *offset_result = static_cast<int>(decomposed.tm_gmtoff);
+  return true;
 }