From 55c04eb9203a93db1c0816adddf3182b45da5384 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Mon, 13 Jul 2020 12:10:09 -0700 Subject: Export of internal Abseil changes -- 69b3ab092ee0fef3d27f589e709280c341f006c6 by Greg Falcon : Import of CCTZ from GitHub. PiperOrigin-RevId: 321005878 -- 3a4038cd0cea6455453a7ae82f2de7e91d7e2bc1 by Abseil Team : Google-internal changes only. PiperOrigin-RevId: 320994821 -- f9d9a93782924df6ffc351a271c239ca4bdff3c8 by Derek Mauro : Update Linux latest toolchains, most notably to GCC 10.1 This create a new "hybrid" docker image that includes the latest versions of both GCC and LLVM. Since the LLVM build targets Debian 10, but Debian 10 uses an older version of libstdc++ that doesn't have full C++20 support, the easiest solution is to use the GCC/Debian 10 base image from DockerHub and copy LLVM into it. This also includes fixes to get the build working with the new toolchains. PiperOrigin-RevId: 320991795 -- 43129cd66dc4439b36d85030800a3929f20d9f86 by Abseil Team : Rollback import of CCTZ from GitHub (breaks MSAN tests) - e87b391f0d10ae9c3d2e70e4a3633337d2c5e643 handle "slim" TZif files in TimeZoneInfo::ExtendTransitio... by Bradley White <14679271+devbww@users.noreply.github.com> PiperOrigin-RevId: 320978767 -- 2a343a55f297d433c1521920f0bd20ddd2dc71e8 by Derek Mauro : Use ABSL_HAVE_ATTRIBUTE in thread_annotations.h PiperOrigin-RevId: 320956378 -- f6f3e8333c9ef6e6441586be6587bbfb1c8c8127 by Gennadiy Rozental : Import of CCTZ from GitHub. PiperOrigin-RevId: 320952592 -- 3cc2bcce3533ac1233c0536232b07eea45fe8ed0 by Derek Mauro : Internal change PiperOrigin-RevId: 320862698 -- 4e22066476744609e42c475b55e3cbd874f04c39 by Gennadiy Rozental : Internal change PiperOrigin-RevId: 320461277 GitOrigin-RevId: 69b3ab092ee0fef3d27f589e709280c341f006c6 Change-Id: I36f547711e7078d52f2e0a1ff3f4c903056a2b9e --- absl/time/internal/cctz/src/time_zone_info.cc | 257 +++++++++++++------------- absl/time/internal/cctz/src/time_zone_info.h | 9 +- 2 files changed, 136 insertions(+), 130 deletions(-) (limited to 'absl/time/internal') diff --git a/absl/time/internal/cctz/src/time_zone_info.cc b/absl/time/internal/cctz/src/time_zone_info.cc index 665fb424..7ccda113 100644 --- a/absl/time/internal/cctz/src/time_zone_info.cc +++ b/absl/time/internal/cctz/src/time_zone_info.cc @@ -40,7 +40,6 @@ #include #include #include -#include #include #include #include @@ -83,6 +82,27 @@ const std::int_least32_t kSecsPerYear[2] = { 366 * kSecsPerDay, }; +// Convert a cctz::weekday to a POSIX TZ weekday number (0==Sun, ..., 6=Sat). +inline int ToPosixWeekday(weekday wd) { + switch (wd) { + case weekday::sunday: + return 0; + case weekday::monday: + return 1; + case weekday::tuesday: + return 2; + case weekday::wednesday: + return 3; + case weekday::thursday: + return 4; + case weekday::friday: + return 5; + case weekday::saturday: + return 6; + } + return 0; /*NOTREACHED*/ +} + // Single-byte, unsigned numeric values are encoded directly. inline std::uint_fast8_t Decode8(const char* cp) { return static_cast(*cp) & 0xff; @@ -188,15 +208,13 @@ bool TimeZoneInfo::ResetToBuiltinUTC(const seconds& offset) { tt.is_dst = false; tt.abbr_index = 0; - // We temporarily add some redundant, contemporary (2013 through 2023) + // We temporarily add some redundant, contemporary (2015 through 2025) // transitions for performance reasons. See TimeZoneInfo::LocalTime(). // TODO: Fix the performance issue and remove the extra transitions. transitions_.clear(); transitions_.reserve(12); for (const std::int_fast64_t unix_time : { - -(1LL << 59), // BIG_BANG - 1356998400LL, // 2013-01-01T00:00:00+00:00 - 1388534400LL, // 2014-01-01T00:00:00+00:00 + -(1LL << 59), // a "first half" transition 1420070400LL, // 2015-01-01T00:00:00+00:00 1451606400LL, // 2016-01-01T00:00:00+00:00 1483228800LL, // 2017-01-01T00:00:00+00:00 @@ -206,7 +224,8 @@ bool TimeZoneInfo::ResetToBuiltinUTC(const seconds& offset) { 1609459200LL, // 2021-01-01T00:00:00+00:00 1640995200LL, // 2022-01-01T00:00:00+00:00 1672531200LL, // 2023-01-01T00:00:00+00:00 - 2147483647LL, // 2^31 - 1 + 1704067200LL, // 2024-01-01T00:00:00+00:00 + 1735689600LL, // 2025-01-01T00:00:00+00:00 }) { Transition& tr(*transitions_.emplace(transitions_.end())); tr.unix_time = unix_time; @@ -217,8 +236,8 @@ bool TimeZoneInfo::ResetToBuiltinUTC(const seconds& offset) { default_transition_type_ = 0; abbreviations_ = FixedOffsetToAbbr(offset); - abbreviations_.append(1, '\0'); // add NUL - future_spec_.clear(); // never needed for a fixed-offset zone + abbreviations_.append(1, '\0'); + future_spec_.clear(); // never needed for a fixed-offset zone extended_ = false; tt.civil_max = LocalTime(seconds::max().count(), tt).cs; @@ -259,21 +278,6 @@ std::size_t TimeZoneInfo::Header::DataLength(std::size_t time_len) const { return len; } -// Check that the TransitionType has the expected offset/is_dst/abbreviation. -void TimeZoneInfo::CheckTransition(const std::string& name, - const TransitionType& tt, - std::int_fast32_t offset, bool is_dst, - const std::string& abbr) const { - if (tt.utc_offset != offset || tt.is_dst != is_dst || - &abbreviations_[tt.abbr_index] != abbr) { - std::clog << name << ": Transition" - << " offset=" << tt.utc_offset << "/" - << (tt.is_dst ? "DST" : "STD") - << "/abbr=" << &abbreviations_[tt.abbr_index] - << " does not match POSIX spec '" << future_spec_ << "'\n"; - } -} - // zic(8) can generate no-op transitions when a zone changes rules at an // instant when there is actually no discontinuity. So we check whether // two transitions have equivalent types (same offset/is_dst/abbr). @@ -282,117 +286,108 @@ bool TimeZoneInfo::EquivTransitions(std::uint_fast8_t tt1_index, if (tt1_index == tt2_index) return true; const TransitionType& tt1(transition_types_[tt1_index]); const TransitionType& tt2(transition_types_[tt2_index]); - if (tt1.is_dst != tt2.is_dst) return false; if (tt1.utc_offset != tt2.utc_offset) return false; + if (tt1.is_dst != tt2.is_dst) return false; if (tt1.abbr_index != tt2.abbr_index) return false; return true; } +// Find/make a transition type with these attributes. +bool TimeZoneInfo::GetTransitionType(std::int_fast32_t utc_offset, bool is_dst, + const std::string& abbr, + std::uint_fast8_t* index) { + std::size_t type_index = 0; + std::size_t abbr_index = abbreviations_.size(); + for (; type_index != transition_types_.size(); ++type_index) { + const TransitionType& tt(transition_types_[type_index]); + const char* tt_abbr = &abbreviations_[tt.abbr_index]; + if (tt_abbr == abbr) abbr_index = tt.abbr_index; + if (tt.utc_offset == utc_offset && tt.is_dst == is_dst) { + if (abbr_index == tt.abbr_index) break; // reuse + } + } + if (type_index > 255 || abbr_index > 255) { + // No index space (8 bits) available for a new type or abbreviation. + return false; + } + if (type_index == transition_types_.size()) { + TransitionType& tt(*transition_types_.emplace(transition_types_.end())); + tt.utc_offset = static_cast(utc_offset); + tt.is_dst = is_dst; + if (abbr_index == abbreviations_.size()) { + abbreviations_.append(abbr); + abbreviations_.append(1, '\0'); + } + tt.abbr_index = static_cast(abbr_index); + } + *index = static_cast(type_index); + return true; +} + // Use the POSIX-TZ-environment-variable-style string to handle times // in years after the last transition stored in the zoneinfo data. -void TimeZoneInfo::ExtendTransitions(const std::string& name, - const Header& hdr) { +bool TimeZoneInfo::ExtendTransitions() { extended_ = false; - bool extending = !future_spec_.empty(); + if (future_spec_.empty()) return true; // last transition prevails PosixTimeZone posix; - if (extending && !ParsePosixSpec(future_spec_, &posix)) { - std::clog << name << ": Failed to parse '" << future_spec_ << "'\n"; - extending = false; - } - - if (extending && posix.dst_abbr.empty()) { // std only - // The future specification should match the last/default transition, - // and that means that handling the future will fall out naturally. - std::uint_fast8_t index = default_transition_type_; - if (hdr.timecnt != 0) index = transitions_[hdr.timecnt - 1].type_index; - const TransitionType& tt(transition_types_[index]); - CheckTransition(name, tt, posix.std_offset, false, posix.std_abbr); - extending = false; - } - - if (extending && hdr.timecnt < 2) { - std::clog << name << ": Too few transitions for POSIX spec\n"; - extending = false; - } - - if (!extending) { - // Ensure that there is always a transition in the second half of the - // time line (the BIG_BANG transition is in the first half) so that the - // signed difference between a civil_second and the civil_second of its - // previous transition is always representable, without overflow. - const Transition& last(transitions_.back()); - if (last.unix_time < 0) { - const std::uint_fast8_t type_index = last.type_index; - Transition& tr(*transitions_.emplace(transitions_.end())); - tr.unix_time = 2147483647; // 2038-01-19T03:14:07+00:00 - tr.type_index = type_index; - } - return; // last transition wins + if (!ParsePosixSpec(future_spec_, &posix)) return false; + + // Find transition type for the future std specification. + std::uint_fast8_t std_ti; + if (!GetTransitionType(posix.std_offset, false, posix.std_abbr, &std_ti)) + return false; + + if (posix.dst_abbr.empty()) { // std only + // The future specification should match the last transition, and + // that means that handling the future will fall out naturally. + return EquivTransitions(transitions_.back().type_index, std_ti); } + // Find transition type for the future dst specification. + std::uint_fast8_t dst_ti; + if (!GetTransitionType(posix.dst_offset, true, posix.dst_abbr, &dst_ti)) + return false; + // Extend the transitions for an additional 400 years using the // future specification. Years beyond those can be handled by // mapping back to a cycle-equivalent year within that range. - // zic(8) should probably do this so that we don't have to. - // TODO: Reduce the extension by the number of compatible - // transitions already in place. - transitions_.reserve(hdr.timecnt + 400 * 2 + 1); - transitions_.resize(hdr.timecnt + 400 * 2); + // We may need two additional transitions for the current year. + transitions_.reserve(transitions_.size() + 400 * 2 + 2); extended_ = true; - // The future specification should match the last two transitions, - // and those transitions should have different is_dst flags. Note - // that nothing says the UTC offset used by the is_dst transition - // must be greater than that used by the !is_dst transition. (See - // Europe/Dublin, for example.) - const Transition* tr0 = &transitions_[hdr.timecnt - 1]; - const Transition* tr1 = &transitions_[hdr.timecnt - 2]; - const TransitionType* tt0 = &transition_types_[tr0->type_index]; - const TransitionType* tt1 = &transition_types_[tr1->type_index]; - const TransitionType& dst(tt0->is_dst ? *tt0 : *tt1); - const TransitionType& std(tt0->is_dst ? *tt1 : *tt0); - CheckTransition(name, dst, posix.dst_offset, true, posix.dst_abbr); - CheckTransition(name, std, posix.std_offset, false, posix.std_abbr); - - // Add the transitions to tr1 and back to tr0 for each extra year. - last_year_ = LocalTime(tr0->unix_time, *tt0).cs.year(); + const Transition& last(transitions_.back()); + const std::int_fast64_t last_time = last.unix_time; + const TransitionType& last_tt(transition_types_[last.type_index]); + last_year_ = LocalTime(last_time, last_tt).cs.year(); bool leap_year = IsLeap(last_year_); - const civil_day jan1(last_year_, 1, 1); - std::int_fast64_t jan1_time = civil_second(jan1) - civil_second(); - int jan1_weekday = (static_cast(get_weekday(jan1)) + 1) % 7; - Transition* tr = &transitions_[hdr.timecnt]; // next trans to fill - if (LocalTime(tr1->unix_time, *tt1).cs.year() != last_year_) { - // Add a single extra transition to align to a calendar year. - transitions_.resize(transitions_.size() + 1); - assert(tr == &transitions_[hdr.timecnt]); // no reallocation - const PosixTransition& pt1(tt0->is_dst ? posix.dst_end : posix.dst_start); - std::int_fast64_t tr1_offset = TransOffset(leap_year, jan1_weekday, pt1); - tr->unix_time = jan1_time + tr1_offset - tt0->utc_offset; - tr++->type_index = tr1->type_index; - tr0 = &transitions_[hdr.timecnt]; - tr1 = &transitions_[hdr.timecnt - 1]; - tt0 = &transition_types_[tr0->type_index]; - tt1 = &transition_types_[tr1->type_index]; - } - const PosixTransition& pt1(tt0->is_dst ? posix.dst_end : posix.dst_start); - const PosixTransition& pt0(tt0->is_dst ? posix.dst_start : posix.dst_end); - for (const year_t limit = last_year_ + 400; last_year_ < limit;) { - last_year_ += 1; // an additional year of generated transitions + const civil_second jan1(last_year_); + std::int_fast64_t jan1_time = jan1 - civil_second(); + int jan1_weekday = ToPosixWeekday(get_weekday(jan1)); + + Transition dst = {0, dst_ti, civil_second(), civil_second()}; + Transition std = {0, std_ti, civil_second(), civil_second()}; + for (const year_t limit = last_year_ + 400;; ++last_year_) { + auto dst_trans_off = TransOffset(leap_year, jan1_weekday, posix.dst_start); + auto std_trans_off = TransOffset(leap_year, jan1_weekday, posix.dst_end); + dst.unix_time = jan1_time + dst_trans_off - posix.std_offset; + std.unix_time = jan1_time + std_trans_off - posix.dst_offset; + const auto* ta = dst.unix_time < std.unix_time ? &dst : &std; + const auto* tb = dst.unix_time < std.unix_time ? &std : &dst; + if (last_time < tb->unix_time) { + if (last_time < ta->unix_time) transitions_.push_back(*ta); + transitions_.push_back(*tb); + } + if (last_year_ == limit) break; jan1_time += kSecsPerYear[leap_year]; jan1_weekday = (jan1_weekday + kDaysPerYear[leap_year]) % 7; - leap_year = !leap_year && IsLeap(last_year_); - std::int_fast64_t tr1_offset = TransOffset(leap_year, jan1_weekday, pt1); - tr->unix_time = jan1_time + tr1_offset - tt0->utc_offset; - tr++->type_index = tr1->type_index; - std::int_fast64_t tr0_offset = TransOffset(leap_year, jan1_weekday, pt0); - tr->unix_time = jan1_time + tr0_offset - tt1->utc_offset; - tr++->type_index = tr0->type_index; - } - assert(tr == &transitions_[0] + transitions_.size()); + leap_year = !leap_year && IsLeap(last_year_ + 1); + } + + return true; } -bool TimeZoneInfo::Load(const std::string& name, ZoneInfoSource* zip) { +bool TimeZoneInfo::Load(ZoneInfoSource* zip) { // Read and validate the header. tzhead tzh; if (zip->Read(&tzh, sizeof(tzh)) != sizeof(tzh)) return false; @@ -430,7 +425,7 @@ bool TimeZoneInfo::Load(const std::string& name, ZoneInfoSource* zip) { const char* bp = tbuf.data(); // Decode and validate the transitions. - transitions_.reserve(hdr.timecnt + 2); // We might add a couple. + transitions_.reserve(hdr.timecnt + 2); transitions_.resize(hdr.timecnt); for (std::size_t i = 0; i != hdr.timecnt; ++i) { transitions_[i].unix_time = (time_len == 4) ? Decode32(bp) : Decode64(bp); @@ -449,6 +444,7 @@ bool TimeZoneInfo::Load(const std::string& name, ZoneInfoSource* zip) { } // Decode and validate the transition types. + transition_types_.reserve(hdr.typecnt + 2); transition_types_.resize(hdr.typecnt); for (std::size_t i = 0; i != hdr.typecnt; ++i) { transition_types_[i].utc_offset = @@ -475,6 +471,7 @@ bool TimeZoneInfo::Load(const std::string& name, ZoneInfoSource* zip) { } // Copy all the abbreviations. + abbreviations_.reserve(hdr.charcnt + 10); abbreviations_.assign(bp, hdr.charcnt); bp += hdr.charcnt; @@ -525,19 +522,29 @@ bool TimeZoneInfo::Load(const std::string& name, ZoneInfoSource* zip) { transitions_.resize(hdr.timecnt); // Ensure that there is always a transition in the first half of the - // time line (the second half is handled in ExtendTransitions()) so that - // the signed difference between a civil_second and the civil_second of - // its previous transition is always representable, without overflow. - // A contemporary zic will usually have already done this for us. + // time line (the second half is handled below) so that the signed + // difference between a civil_second and the civil_second of its + // previous transition is always representable, without overflow. if (transitions_.empty() || transitions_.front().unix_time >= 0) { Transition& tr(*transitions_.emplace(transitions_.begin())); - tr.unix_time = -(1LL << 59); // see tz/zic.c "BIG_BANG" + tr.unix_time = -(1LL << 59); // -18267312070-10-26T17:01:52+00:00 tr.type_index = default_transition_type_; - hdr.timecnt += 1; } // Extend the transitions using the future specification. - ExtendTransitions(name, hdr); + if (!ExtendTransitions()) return false; + + // Ensure that there is always a transition in the second half of the + // time line (the first half is handled above) so that the signed + // difference between a civil_second and the civil_second of its + // previous transition is always representable, without overflow. + const Transition& last(transitions_.back()); + if (last.unix_time < 0) { + const std::uint_fast8_t type_index = last.type_index; + Transition& tr(*transitions_.emplace(transitions_.end())); + tr.unix_time = 2147483647; // 2038-01-19T03:14:07+00:00 + tr.type_index = type_index; + } // Compute the local civil time for each transition and the preceding // second. These will be used for reverse conversions in MakeTime(). @@ -723,7 +730,7 @@ bool TimeZoneInfo::Load(const std::string& name) { if (auto zip = AndroidZoneInfoSource::Open(name)) return zip; return nullptr; }); - return zip != nullptr && Load(name, zip.get()); + return zip != nullptr && Load(zip.get()); } // BreakTime() translation for a particular transition type. @@ -897,8 +904,8 @@ bool TimeZoneInfo::NextTransition(const time_point& tp, const Transition* begin = &transitions_[0]; const Transition* end = begin + transitions_.size(); if (begin->unix_time <= -(1LL << 59)) { - // Do not report the BIG_BANG found in recent zoneinfo data as it is - // really a sentinel, not a transition. See tz/zic.c. + // Do not report the BIG_BANG found in some zoneinfo data as it is + // really a sentinel, not a transition. See pre-2018f tz/zic.c. ++begin; } std::int_fast64_t unix_time = ToUnixSeconds(tp); @@ -923,8 +930,8 @@ bool TimeZoneInfo::PrevTransition(const time_point& tp, const Transition* begin = &transitions_[0]; const Transition* end = begin + transitions_.size(); if (begin->unix_time <= -(1LL << 59)) { - // Do not report the BIG_BANG found in recent zoneinfo data as it is - // really a sentinel, not a transition. See tz/zic.c. + // Do not report the BIG_BANG found in some zoneinfo data as it is + // really a sentinel, not a transition. See pre-2018f tz/zic.c. ++begin; } std::int_fast64_t unix_time = ToUnixSeconds(tp); diff --git a/absl/time/internal/cctz/src/time_zone_info.h b/absl/time/internal/cctz/src/time_zone_info.h index 2a10c06c..068e34be 100644 --- a/absl/time/internal/cctz/src/time_zone_info.h +++ b/absl/time/internal/cctz/src/time_zone_info.h @@ -95,15 +95,14 @@ class TimeZoneInfo : public TimeZoneIf { std::size_t DataLength(std::size_t time_len) const; }; - void CheckTransition(const std::string& name, const TransitionType& tt, - std::int_fast32_t offset, bool is_dst, - const std::string& abbr) const; + bool GetTransitionType(std::int_fast32_t utc_offset, bool is_dst, + const std::string& abbr, std::uint_fast8_t* index); bool EquivTransitions(std::uint_fast8_t tt1_index, std::uint_fast8_t tt2_index) const; - void ExtendTransitions(const std::string& name, const Header& hdr); + bool ExtendTransitions(); bool ResetToBuiltinUTC(const seconds& offset); - bool Load(const std::string& name, ZoneInfoSource* zip); + bool Load(ZoneInfoSource* zip); // Helpers for BreakTime() and MakeTime(). time_zone::absolute_lookup LocalTime(std::int_fast64_t unix_time, -- cgit v1.2.3