256be56344
-- 00d42e3d5433aaf29c2ed293520b2ba178ae8bdb by Greg Falcon <gfalcon@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 238061818 -- 867a7ca318fac2991ea9a4107dbae3cc9fbf974a by Abseil Team <absl-team@google.com>: Added a IWYU export pragma when including a standard header for the purpose of aliasing its symbols. PiperOrigin-RevId: 238022277 -- 17047745058f2f151cd986ea9f649512542d3876 by Matt Armstrong <marmstrong@google.com>: Clarify the comment discouraging WrapUnique<T>(x) calls. PiperOrigin-RevId: 237873803 -- 3dcb2e4968243d33ca0ce53280c445df50f4a7ec by Samuel Benzaquen <sbenza@google.com>: Workaround clang bug https://bugs.llvm.org/show_bug.cgi?id=38289 PiperOrigin-RevId: 237873551 -- f348d2dc7087a990cbdfb95aa51fd7ff478ae40e by Samuel Benzaquen <sbenza@google.com>: Reduce minimum capacity to 1. This reduces memory usage for small tables. A flat_hash_set<int> of 1 element goes from 92 bytes to 24. A flat_hash_set<string> of 1 element goes from 512 bytes to 56. PiperOrigin-RevId: 237859811 -- 9c8125be5e4e5d22a7bb62bdec8c323338385c1b by Jon Cohen <cohenjon@google.com>: Bump to CMake 3.5. This is the oldest modern cmake being included by default in most popular OS distributions according to https://repology.org/project/cmake/versions. Specifically, Ubuntu LTS 16.04 uses cmake 3.5 (https://packages.ubuntu.com/xenial/cmake) PiperOrigin-RevId: 237859345 -- 07638d672e0a4dced986a62750cfd8318ed36ffa by Derek Mauro <dmauro@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 237714597 GitOrigin-RevId: 00d42e3d5433aaf29c2ed293520b2ba178ae8bdb Change-Id: I5faecc45add4a5a774d4f9baf06e5519091f2ccc
96 lines
3.5 KiB
C++
96 lines
3.5 KiB
C++
// Copyright 2016 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef ABSL_TIME_INTERNAL_CCTZ_ZONE_INFO_SOURCE_H_
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#define ABSL_TIME_INTERNAL_CCTZ_ZONE_INFO_SOURCE_H_
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#include <cstddef>
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#include <functional>
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#include <memory>
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#include <string>
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namespace absl {
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namespace time_internal {
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namespace cctz {
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// A stdio-like interface for providing zoneinfo data for a particular zone.
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class ZoneInfoSource {
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public:
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virtual ~ZoneInfoSource();
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virtual std::size_t Read(void* ptr, std::size_t size) = 0; // like fread()
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virtual int Skip(std::size_t offset) = 0; // like fseek()
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// Until the zoneinfo data supports versioning information, we provide
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// a way for a ZoneInfoSource to indicate it out-of-band. The default
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// implementation returns an empty std::string.
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virtual std::string Version() const;
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};
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} // namespace cctz
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} // namespace time_internal
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} // namespace absl
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namespace absl {
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namespace time_internal {
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namespace cctz_extension {
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// A function-pointer type for a factory that returns a ZoneInfoSource
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// given the name of a time zone and a fallback factory. Returns null
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// when the data for the named zone cannot be found.
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using ZoneInfoSourceFactory =
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std::unique_ptr<absl::time_internal::cctz::ZoneInfoSource> (*)(
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const std::string&,
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const std::function<std::unique_ptr<absl::time_internal::cctz::ZoneInfoSource>(
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const std::string&)>&);
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// The user can control the mapping of zone names to zoneinfo data by
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// providing a definition for cctz_extension::zone_info_source_factory.
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// For example, given functions my_factory() and my_other_factory() that
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// can return a ZoneInfoSource for a named zone, we could inject them into
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// cctz::load_time_zone() with:
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//
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// namespace cctz_extension {
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// namespace {
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// std::unique_ptr<cctz::ZoneInfoSource> CustomFactory(
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// const std::string& name,
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// const std::function<std::unique_ptr<cctz::ZoneInfoSource>(
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// const std::string& name)>& fallback_factory) {
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// if (auto zip = my_factory(name)) return zip;
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// if (auto zip = fallback_factory(name)) return zip;
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// if (auto zip = my_other_factory(name)) return zip;
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// return nullptr;
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// }
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// } // namespace
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// ZoneInfoSourceFactory zone_info_source_factory = CustomFactory;
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// } // namespace cctz_extension
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//
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// This might be used, say, to use zoneinfo data embedded in the program,
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// or read from a (possibly compressed) file archive, or both.
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//
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// cctz_extension::zone_info_source_factory() will be called:
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// (1) from the same thread as the cctz::load_time_zone() call,
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// (2) only once for any zone name, and
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// (3) serially (i.e., no concurrent execution).
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//
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// The fallback factory obtains zoneinfo data by reading files in ${TZDIR},
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// and it is used automatically when no zone_info_source_factory definition
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// is linked into the program.
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extern ZoneInfoSourceFactory zone_info_source_factory;
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} // namespace cctz_extension
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} // namespace time_internal
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} // namespace absl
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#endif // ABSL_TIME_INTERNAL_CCTZ_ZONE_INFO_SOURCE_H_
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