- fd5f3d7077270ffc5ea74cdb9e18bbae3b9b46aa Fix typo optional -> variant by Abseil Team <absl-team@google.com>

- 9136c06dfa8dbfdde0a427ad3509e34763d607a6 Fix string_view_test and str_cat_test build under MSVC de... by Derek Mauro <dmauro@google.com>
  - a463820f9441888f4368aa87328599e3209f9b07 Removes constexpr optional<T>::operator->(). This was don... by Abseil Team <absl-team@google.com>
  - 3bf78a7f126daafff329f7815d507422f1ca378d Remove dependencies on external CCTZ project. by Shaindel Schwartz <shaindel@google.com>
  - a4ae574a11b1ddf6e88459af3d638cf79aea7ecd Internal change by Jon Cohen <cohenjon@google.com>

GitOrigin-RevId: fd5f3d7077270ffc5ea74cdb9e18bbae3b9b46aa
Change-Id: I6ab8ab99863716fe9b2745a12ef285f7a6da6d1e

absl/time/internal/cctz/src/time_zone_impl.h

@@ -0,0 +1,97 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+//   Unless required by applicable law or agreed to in writing, software
+//   distributed under the License is distributed on an "AS IS" BASIS,
+//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//   See the License for the specific language governing permissions and
+//   limitations under the License.
+
+#ifndef ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_IMPL_H_
+#define ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_IMPL_H_
+
+#include <memory>
+#include <string>
+
+#include "absl/time/internal/cctz/include/cctz/civil_time.h"
+#include "absl/time/internal/cctz/include/cctz/time_zone.h"
+#include "time_zone_if.h"
+#include "time_zone_info.h"
+
+namespace absl {
+namespace time_internal {
+namespace cctz {
+
+// time_zone::Impl is the internal object referenced by a cctz::time_zone.
+class time_zone::Impl {
+ public:
+  // The UTC time zone. Also used for other time zones that fail to load.
+  static time_zone UTC();
+
+  // Load a named time zone. Returns false if the name is invalid, or if
+  // some other kind of error occurs. Note that loading "UTC" never fails.
+  static bool LoadTimeZone(const std::string& name, time_zone* tz);
+
+  // Dereferences the time_zone to obtain its Impl.
+  static const time_zone::Impl& get(const time_zone& tz);
+
+  // Clears the map of cached time zones.  Primarily for use in benchmarks
+  // that gauge the performance of loading/parsing the time-zone data.
+  static void ClearTimeZoneMapTestOnly();
+
+  // The primary key is the time-zone ID (e.g., "America/New_York").
+  const std::string& name() const { return name_; }
+
+  // Breaks a time_point down to civil-time components in this time zone.
+  time_zone::absolute_lookup BreakTime(
+      const time_point<sys_seconds>& tp) const {
+    return zone_->BreakTime(tp);
+  }
+
+  // Converts the civil-time components in this time zone into a time_point.
+  // That is, the opposite of BreakTime(). The requested civil time may be
+  // ambiguous or illegal due to a change of UTC offset.
+  time_zone::civil_lookup MakeTime(const civil_second& cs) const {
+    return zone_->MakeTime(cs);
+  }
+
+  // Returns an implementation-specific description of this time zone.
+  std::string Description() const { return zone_->Description(); }
+
+  // Finds the time of the next/previous offset change in this time zone.
+  //
+  // By definition, NextTransition(&tp) returns false when tp has its
+  // maximum value, and PrevTransition(&tp) returns false when tp has its
+  // mimimum value.  If the zone has no transitions, the result will also
+  // be false no matter what the argument.
+  //
+  // Otherwise, when tp has its mimimum value, NextTransition(&tp) returns
+  // true and sets tp to the first recorded transition.  Chains of calls
+  // to NextTransition()/PrevTransition() will eventually return false,
+  // but it is unspecified exactly when NextTransition(&tp) jumps to false,
+  // or what time is set by PrevTransition(&tp) for a very distant tp.
+  bool NextTransition(time_point<sys_seconds>* tp) const {
+    return zone_->NextTransition(tp);
+  }
+  bool PrevTransition(time_point<sys_seconds>* tp) const {
+    return zone_->PrevTransition(tp);
+  }
+
+ private:
+  explicit Impl(const std::string& name);
+  static const Impl* UTCImpl();
+
+  const std::string name_;
+  std::unique_ptr<TimeZoneIf> zone_;
+};
+
+}  // namespace cctz
+}  // namespace time_internal
+}  // namespace absl
+
+#endif  // ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_IMPL_H_