diff options
author | Abseil Team <absl-team@google.com> | 2018-04-23 08:17:58 -0700 |
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committer | Derek Mauro <dmauro@google.com> | 2018-04-23 12:57:34 -0400 |
commit | af7882601aad93ada881486eeaabc562f1733961 (patch) | |
tree | e9a52b01ef69c7654a97d66c8d60377c851ae817 /absl/time/internal/cctz/include/cctz/zone_info_source.h | |
parent | 94ce52d46c171683b1ee22d14277a6d3bdfd7c4c (diff) |
- 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
Diffstat (limited to 'absl/time/internal/cctz/include/cctz/zone_info_source.h')
-rw-r--r-- | absl/time/internal/cctz/include/cctz/zone_info_source.h | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/absl/time/internal/cctz/include/cctz/zone_info_source.h b/absl/time/internal/cctz/include/cctz/zone_info_source.h new file mode 100644 index 0000000..4d9d8f8 --- /dev/null +++ b/absl/time/internal/cctz/include/cctz/zone_info_source.h @@ -0,0 +1,91 @@ +// 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_ZONE_INFO_SOURCE_H_ +#define ABSL_TIME_INTERNAL_CCTZ_ZONE_INFO_SOURCE_H_ + +#include <cstddef> +#include <functional> +#include <memory> +#include <string> + +namespace absl { +namespace time_internal { +namespace cctz { + +// A stdio-like interface for providing zoneinfo data for a particular zone. +class ZoneInfoSource { + public: + virtual ~ZoneInfoSource(); + + virtual std::size_t Read(void* ptr, std::size_t size) = 0; // like fread() + virtual int Skip(std::size_t offset) = 0; // like fseek() +}; + +} // namespace cctz +} // namespace time_internal +} // namespace absl + +namespace absl { +namespace time_internal { +namespace cctz_extension { + +// A function-pointer type for a factory that returns a ZoneInfoSource +// given the name of a time zone and a fallback factory. Returns null +// when the data for the named zone cannot be found. +using ZoneInfoSourceFactory = + std::unique_ptr<absl::time_internal::cctz::ZoneInfoSource> (*)( + const std::string&, + const std::function<std::unique_ptr<absl::time_internal::cctz::ZoneInfoSource>( + const std::string&)>&); + +// The user can control the mapping of zone names to zoneinfo data by +// providing a definition for cctz_extension::zone_info_source_factory. +// For example, given functions my_factory() and my_other_factory() that +// can return a ZoneInfoSource for a named zone, we could inject them into +// cctz::load_time_zone() with: +// +// namespace cctz_extension { +// namespace { +// std::unique_ptr<cctz::ZoneInfoSource> CustomFactory( +// const std::string& name, +// const std::function<std::unique_ptr<cctz::ZoneInfoSource>( +// const std::string& name)>& fallback_factory) { +// if (auto zip = my_factory(name)) return zip; +// if (auto zip = fallback_factory(name)) return zip; +// if (auto zip = my_other_factory(name)) return zip; +// return nullptr; +// } +// } // namespace +// ZoneInfoSourceFactory zone_info_source_factory = CustomFactory; +// } // namespace cctz_extension +// +// This might be used, say, to use zoneinfo data embedded in the program, +// or read from a (possibly compressed) file archive, or both. +// +// cctz_extension::zone_info_source_factory() will be called: +// (1) from the same thread as the cctz::load_time_zone() call, +// (2) only once for any zone name, and +// (3) serially (i.e., no concurrent execution). +// +// The fallback factory obtains zoneinfo data by reading files in ${TZDIR}, +// and it is used automatically when no zone_info_source_factory definition +// is linked into the program. +extern ZoneInfoSourceFactory zone_info_source_factory; + +} // namespace cctz_extension +} // namespace time_internal +} // namespace absl + +#endif // ABSL_TIME_INTERNAL_CCTZ_ZONE_INFO_SOURCE_H_ |