diff options
Diffstat (limited to 'abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc')
| -rw-r--r-- | abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc | 594 |
1 files changed, 352 insertions, 242 deletions
diff --git a/abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc b/abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc index 8039353..f46198f 100644 --- a/abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc +++ b/abseil-cpp/absl/time/internal/cctz/src/time_zone_info.cc @@ -39,10 +39,13 @@ #include <cstdio> #include <cstdlib> #include <cstring> +#include <fstream> #include <functional> #include <memory> #include <sstream> #include <string> +#include <utility> +#include <vector> #include "absl/base/config.h" #include "absl/time/internal/cctz/include/cctz/civil_time.h" @@ -132,6 +135,64 @@ std::int_fast64_t Decode64(const char* cp) { return static_cast<std::int_fast64_t>(v - s64maxU - 1) - s64max - 1; } +struct Header { // counts of: + std::size_t timecnt; // transition times + std::size_t typecnt; // transition types + std::size_t charcnt; // zone abbreviation characters + std::size_t leapcnt; // leap seconds (we expect none) + std::size_t ttisstdcnt; // UTC/local indicators (unused) + std::size_t ttisutcnt; // standard/wall indicators (unused) + + bool Build(const tzhead& tzh); + std::size_t DataLength(std::size_t time_len) const; +}; + +// Builds the in-memory header using the raw bytes from the file. +bool Header::Build(const tzhead& tzh) { + std::int_fast32_t v; + if ((v = Decode32(tzh.tzh_timecnt)) < 0) return false; + timecnt = static_cast<std::size_t>(v); + if ((v = Decode32(tzh.tzh_typecnt)) < 0) return false; + typecnt = static_cast<std::size_t>(v); + if ((v = Decode32(tzh.tzh_charcnt)) < 0) return false; + charcnt = static_cast<std::size_t>(v); + if ((v = Decode32(tzh.tzh_leapcnt)) < 0) return false; + leapcnt = static_cast<std::size_t>(v); + if ((v = Decode32(tzh.tzh_ttisstdcnt)) < 0) return false; + ttisstdcnt = static_cast<std::size_t>(v); + if ((v = Decode32(tzh.tzh_ttisutcnt)) < 0) return false; + ttisutcnt = static_cast<std::size_t>(v); + return true; +} + +// How many bytes of data are associated with this header. The result +// depends upon whether this is a section with 4-byte or 8-byte times. +std::size_t Header::DataLength(std::size_t time_len) const { + std::size_t len = 0; + len += (time_len + 1) * timecnt; // unix_time + type_index + len += (4 + 1 + 1) * typecnt; // utc_offset + is_dst + abbr_index + len += 1 * charcnt; // abbreviations + len += (time_len + 4) * leapcnt; // leap-time + TAI-UTC + len += 1 * ttisstdcnt; // UTC/local indicators + len += 1 * ttisutcnt; // standard/wall indicators + return len; +} + +// Does the rule for future transitions call for year-round daylight time? +// See tz/zic.c:stringzone() for the details on how such rules are encoded. +bool AllYearDST(const PosixTimeZone& posix) { + if (posix.dst_start.date.fmt != PosixTransition::N) return false; + if (posix.dst_start.date.n.day != 0) return false; + if (posix.dst_start.time.offset != 0) return false; + + if (posix.dst_end.date.fmt != PosixTransition::J) return false; + if (posix.dst_end.date.j.day != kDaysPerYear[0]) return false; + const auto offset = posix.std_offset - posix.dst_offset; + if (posix.dst_end.time.offset + offset != kSecsPerDay) return false; + + return true; +} + // Generate a year-relative offset for a PosixTransition. std::int_fast64_t TransOffset(bool leap_year, int jan1_weekday, const PosixTransition& pt) { @@ -200,98 +261,6 @@ inline civil_second YearShift(const civil_second& cs, year_t shift) { } // namespace -// What (no leap-seconds) UTC+seconds zoneinfo would look like. -bool TimeZoneInfo::ResetToBuiltinUTC(const seconds& offset) { - transition_types_.resize(1); - TransitionType& tt(transition_types_.back()); - tt.utc_offset = static_cast<std::int_least32_t>(offset.count()); - tt.is_dst = false; - tt.abbr_index = 0; - - // 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), // 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 - 1514764800LL, // 2018-01-01T00:00:00+00:00 - 1546300800LL, // 2019-01-01T00:00:00+00:00 - 1577836800LL, // 2020-01-01T00:00:00+00:00 - 1609459200LL, // 2021-01-01T00:00:00+00:00 - 1640995200LL, // 2022-01-01T00:00:00+00:00 - 1672531200LL, // 2023-01-01T00:00:00+00:00 - 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; - tr.type_index = 0; - tr.civil_sec = LocalTime(tr.unix_time, tt).cs; - tr.prev_civil_sec = tr.civil_sec - 1; - } - - default_transition_type_ = 0; - abbreviations_ = FixedOffsetToAbbr(offset); - 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; - tt.civil_min = LocalTime(seconds::min().count(), tt).cs; - - transitions_.shrink_to_fit(); - return true; -} - -// Builds the in-memory header using the raw bytes from the file. -bool TimeZoneInfo::Header::Build(const tzhead& tzh) { - std::int_fast32_t v; - if ((v = Decode32(tzh.tzh_timecnt)) < 0) return false; - timecnt = static_cast<std::size_t>(v); - if ((v = Decode32(tzh.tzh_typecnt)) < 0) return false; - typecnt = static_cast<std::size_t>(v); - if ((v = Decode32(tzh.tzh_charcnt)) < 0) return false; - charcnt = static_cast<std::size_t>(v); - if ((v = Decode32(tzh.tzh_leapcnt)) < 0) return false; - leapcnt = static_cast<std::size_t>(v); - if ((v = Decode32(tzh.tzh_ttisstdcnt)) < 0) return false; - ttisstdcnt = static_cast<std::size_t>(v); - if ((v = Decode32(tzh.tzh_ttisutcnt)) < 0) return false; - ttisutcnt = static_cast<std::size_t>(v); - return true; -} - -// How many bytes of data are associated with this header. The result -// depends upon whether this is a section with 4-byte or 8-byte times. -std::size_t TimeZoneInfo::Header::DataLength(std::size_t time_len) const { - std::size_t len = 0; - len += (time_len + 1) * timecnt; // unix_time + type_index - len += (4 + 1 + 1) * typecnt; // utc_offset + is_dst + abbr_index - len += 1 * charcnt; // abbreviations - len += (time_len + 4) * leapcnt; // leap-time + TAI-UTC - len += 1 * ttisstdcnt; // UTC/local indicators - len += 1 * ttisutcnt; // standard/wall indicators - return len; -} - -// 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). -bool TimeZoneInfo::EquivTransitions(std::uint_fast8_t tt1_index, - std::uint_fast8_t tt2_index) const { - if (tt1_index == tt2_index) return true; - const TransitionType& tt1(transition_types_[tt1_index]); - const TransitionType& tt2(transition_types_[tt2_index]); - 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, @@ -324,6 +293,20 @@ bool TimeZoneInfo::GetTransitionType(std::int_fast32_t utc_offset, bool is_dst, return true; } +// 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). +bool TimeZoneInfo::EquivTransitions(std::uint_fast8_t tt1_index, + std::uint_fast8_t tt2_index) const { + if (tt1_index == tt2_index) return true; + const TransitionType& tt1(transition_types_[tt1_index]); + const TransitionType& tt2(transition_types_[tt2_index]); + 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; +} + // Use the POSIX-TZ-environment-variable-style string to handle times // in years after the last transition stored in the zoneinfo data. bool TimeZoneInfo::ExtendTransitions() { @@ -349,11 +332,19 @@ bool TimeZoneInfo::ExtendTransitions() { 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. - // We may need two additional transitions for the current year. - transitions_.reserve(transitions_.size() + 400 * 2 + 2); + if (AllYearDST(posix)) { // dst 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, dst_ti); + } + + // Extend the transitions for an additional 401 years using the future + // specification. Years beyond those can be handled by mapping back to + // a cycle-equivalent year within that range. Note that we need 401 + // (well, at least the first transition in the 401st year) so that the + // end of the 400th year is mapped back to an extended year. And first + // we may also need two additional transitions for the current year. + transitions_.reserve(transitions_.size() + 2 + 401 * 2); extended_ = true; const Transition& last(transitions_.back()); @@ -367,7 +358,7 @@ bool TimeZoneInfo::ExtendTransitions() { 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_) { + for (const year_t limit = last_year_ + 401;; ++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; @@ -387,6 +378,251 @@ bool TimeZoneInfo::ExtendTransitions() { return true; } +namespace { + +using FilePtr = std::unique_ptr<FILE, int (*)(FILE*)>; + +// fopen(3) adaptor. +inline FilePtr FOpen(const char* path, const char* mode) { +#if defined(_MSC_VER) + FILE* fp; + if (fopen_s(&fp, path, mode) != 0) fp = nullptr; + return FilePtr(fp, fclose); +#else + // TODO: Enable the close-on-exec flag. + return FilePtr(fopen(path, mode), fclose); +#endif +} + +// A stdio(3)-backed implementation of ZoneInfoSource. +class FileZoneInfoSource : public ZoneInfoSource { + public: + static std::unique_ptr<ZoneInfoSource> Open(const std::string& name); + + std::size_t Read(void* ptr, std::size_t size) override { + size = std::min(size, len_); + std::size_t nread = fread(ptr, 1, size, fp_.get()); + len_ -= nread; + return nread; + } + int Skip(std::size_t offset) override { + offset = std::min(offset, len_); + int rc = fseek(fp_.get(), static_cast<long>(offset), SEEK_CUR); + if (rc == 0) len_ -= offset; + return rc; + } + std::string Version() const override { + // TODO: It would nice if the zoneinfo data included the tzdb version. + return std::string(); + } + + protected: + explicit FileZoneInfoSource( + FilePtr fp, std::size_t len = std::numeric_limits<std::size_t>::max()) + : fp_(std::move(fp)), len_(len) {} + + private: + FilePtr fp_; + std::size_t len_; +}; + +std::unique_ptr<ZoneInfoSource> FileZoneInfoSource::Open( + const std::string& name) { + // Use of the "file:" prefix is intended for testing purposes only. + const std::size_t pos = (name.compare(0, 5, "file:") == 0) ? 5 : 0; + + // Map the time-zone name to a path name. + std::string path; + if (pos == name.size() || name[pos] != '/') { + const char* tzdir = "/usr/share/zoneinfo"; + char* tzdir_env = nullptr; +#if defined(_MSC_VER) + _dupenv_s(&tzdir_env, nullptr, "TZDIR"); +#else + tzdir_env = std::getenv("TZDIR"); +#endif + if (tzdir_env && *tzdir_env) tzdir = tzdir_env; + path += tzdir; + path += '/'; +#if defined(_MSC_VER) + free(tzdir_env); +#endif + } + path.append(name, pos, std::string::npos); + + // Open the zoneinfo file. + auto fp = FOpen(path.c_str(), "rb"); + if (fp == nullptr) return nullptr; + return std::unique_ptr<ZoneInfoSource>(new FileZoneInfoSource(std::move(fp))); +} + +class AndroidZoneInfoSource : public FileZoneInfoSource { + public: + static std::unique_ptr<ZoneInfoSource> Open(const std::string& name); + std::string Version() const override { return version_; } + + private: + explicit AndroidZoneInfoSource(FilePtr fp, std::size_t len, + std::string version) + : FileZoneInfoSource(std::move(fp), len), version_(std::move(version)) {} + std::string version_; +}; + +std::unique_ptr<ZoneInfoSource> AndroidZoneInfoSource::Open( + const std::string& name) { + // Use of the "file:" prefix is intended for testing purposes only. + const std::size_t pos = (name.compare(0, 5, "file:") == 0) ? 5 : 0; + + // See Android's libc/tzcode/bionic.cpp for additional information. + for (const char* tzdata : {"/data/misc/zoneinfo/current/tzdata", + "/system/usr/share/zoneinfo/tzdata"}) { + auto fp = FOpen(tzdata, "rb"); + if (fp == nullptr) continue; + + char hbuf[24]; // covers header.zonetab_offset too + if (fread(hbuf, 1, sizeof(hbuf), fp.get()) != sizeof(hbuf)) continue; + if (strncmp(hbuf, "tzdata", 6) != 0) continue; + const char* vers = (hbuf[11] == '\0') ? hbuf + 6 : ""; + const std::int_fast32_t index_offset = Decode32(hbuf + 12); + const std::int_fast32_t data_offset = Decode32(hbuf + 16); + if (index_offset < 0 || data_offset < index_offset) continue; + if (fseek(fp.get(), static_cast<long>(index_offset), SEEK_SET) != 0) + continue; + + char ebuf[52]; // covers entry.unused too + const std::size_t index_size = + static_cast<std::size_t>(data_offset - index_offset); + const std::size_t zonecnt = index_size / sizeof(ebuf); + if (zonecnt * sizeof(ebuf) != index_size) continue; + for (std::size_t i = 0; i != zonecnt; ++i) { + if (fread(ebuf, 1, sizeof(ebuf), fp.get()) != sizeof(ebuf)) break; + const std::int_fast32_t start = data_offset + Decode32(ebuf + 40); + const std::int_fast32_t length = Decode32(ebuf + 44); + if (start < 0 || length < 0) break; + ebuf[40] = '\0'; // ensure zone name is NUL terminated + if (strcmp(name.c_str() + pos, ebuf) == 0) { + if (fseek(fp.get(), static_cast<long>(start), SEEK_SET) != 0) break; + return std::unique_ptr<ZoneInfoSource>(new AndroidZoneInfoSource( + std::move(fp), static_cast<std::size_t>(length), vers)); + } + } + } + + return nullptr; +} + +// A zoneinfo source for use inside Fuchsia components. This attempts to +// read zoneinfo files from one of several known paths in a component's +// incoming namespace. [Config data][1] is preferred, but package-specific +// resources are also supported. +// +// Fuchsia's implementation supports `FileZoneInfoSource::Version()`. +// +// [1]: +// https://fuchsia.dev/fuchsia-src/development/components/data#using_config_data_in_your_component +class FuchsiaZoneInfoSource : public FileZoneInfoSource { + public: + static std::unique_ptr<ZoneInfoSource> Open(const std::string& name); + std::string Version() const override { return version_; } + + private: + explicit FuchsiaZoneInfoSource(FilePtr fp, std::string version) + : FileZoneInfoSource(std::move(fp)), version_(std::move(version)) {} + std::string version_; +}; + +std::unique_ptr<ZoneInfoSource> FuchsiaZoneInfoSource::Open( + const std::string& name) { + // Use of the "file:" prefix is intended for testing purposes only. + const std::size_t pos = (name.compare(0, 5, "file:") == 0) ? 5 : 0; + + // Prefixes where a Fuchsia component might find zoneinfo files, + // in descending order of preference. + const auto kTzdataPrefixes = { + "/config/data/tzdata/", + "/pkg/data/tzdata/", + "/data/tzdata/", + }; + const auto kEmptyPrefix = {""}; + const bool name_absolute = (pos != name.size() && name[pos] == '/'); + const auto prefixes = name_absolute ? kEmptyPrefix : kTzdataPrefixes; + + // Fuchsia builds place zoneinfo files at "<prefix><format><name>". + for (const std::string prefix : prefixes) { + std::string path = prefix; + if (!prefix.empty()) path += "zoneinfo/tzif2/"; // format + path.append(name, pos, std::string::npos); + + auto fp = FOpen(path.c_str(), "rb"); + if (fp == nullptr) continue; + + std::string version; + if (!prefix.empty()) { + // Fuchsia builds place the version in "<prefix>revision.txt". + std::ifstream version_stream(prefix + "revision.txt"); + if (version_stream.is_open()) { + // revision.txt should contain no newlines, but to be + // defensive we read just the first line. + std::getline(version_stream, version); + } + } + + return std::unique_ptr<ZoneInfoSource>( + new FuchsiaZoneInfoSource(std::move(fp), std::move(version))); + } + + return nullptr; +} + +} // namespace + +// What (no leap-seconds) UTC+seconds zoneinfo would look like. +bool TimeZoneInfo::ResetToBuiltinUTC(const seconds& offset) { + transition_types_.resize(1); + TransitionType& tt(transition_types_.back()); + tt.utc_offset = static_cast<std::int_least32_t>(offset.count()); + tt.is_dst = false; + tt.abbr_index = 0; + + // 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), // 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 + 1514764800LL, // 2018-01-01T00:00:00+00:00 + 1546300800LL, // 2019-01-01T00:00:00+00:00 + 1577836800LL, // 2020-01-01T00:00:00+00:00 + 1609459200LL, // 2021-01-01T00:00:00+00:00 + 1640995200LL, // 2022-01-01T00:00:00+00:00 + 1672531200LL, // 2023-01-01T00:00:00+00:00 + 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; + tr.type_index = 0; + tr.civil_sec = LocalTime(tr.unix_time, tt).cs; + tr.prev_civil_sec = tr.civil_sec - 1; + } + + default_transition_type_ = 0; + abbreviations_ = FixedOffsetToAbbr(offset); + 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; + tt.civil_min = LocalTime(seconds::min().count(), tt).cs; + + transitions_.shrink_to_fit(); + return true; +} + bool TimeZoneInfo::Load(ZoneInfoSource* zip) { // Read and validate the header. tzhead tzh; @@ -479,9 +715,9 @@ bool TimeZoneInfo::Load(ZoneInfoSource* zip) { // encoded zoneinfo. The ttisstd/ttisgmt indicators only apply when // interpreting a POSIX spec that does not include start/end rules, and // that isn't the case here (see "zic -p"). - bp += (8 + 4) * hdr.leapcnt; // leap-time + TAI-UTC - bp += 1 * hdr.ttisstdcnt; // UTC/local indicators - bp += 1 * hdr.ttisutcnt; // standard/wall indicators + bp += (time_len + 4) * hdr.leapcnt; // leap-time + TAI-UTC + bp += 1 * hdr.ttisstdcnt; // UTC/local indicators + bp += 1 * hdr.ttisutcnt; // standard/wall indicators assert(bp == tbuf.data() + tbuf.size()); future_spec_.clear(); @@ -510,8 +746,8 @@ bool TimeZoneInfo::Load(ZoneInfoSource* zip) { // Trim redundant transitions. zic may have added these to work around // differences between the glibc and reference implementations (see - // zic.c:dontmerge) and the Qt library (see zic.c:WORK_AROUND_QTBUG_53071). - // For us, they just get in the way when we do future_spec_ extension. + // zic.c:dontmerge) or to avoid bugs in old readers. For us, they just + // get in the way when we do future_spec_ extension. while (hdr.timecnt > 1) { if (!EquivTransitions(transitions_[hdr.timecnt - 1].type_index, transitions_[hdr.timecnt - 2].type_index)) { @@ -574,145 +810,6 @@ bool TimeZoneInfo::Load(ZoneInfoSource* zip) { return true; } -namespace { - -// fopen(3) adaptor. -inline FILE* FOpen(const char* path, const char* mode) { -#if defined(_MSC_VER) - FILE* fp; - if (fopen_s(&fp, path, mode) != 0) fp = nullptr; - return fp; -#else - return fopen(path, mode); // TODO: Enable the close-on-exec flag. -#endif -} - -// A stdio(3)-backed implementation of ZoneInfoSource. -class FileZoneInfoSource : public ZoneInfoSource { - public: - static std::unique_ptr<ZoneInfoSource> Open(const std::string& name); - - std::size_t Read(void* ptr, std::size_t size) override { - size = std::min(size, len_); - std::size_t nread = fread(ptr, 1, size, fp_.get()); - len_ -= nread; - return nread; - } - int Skip(std::size_t offset) override { - offset = std::min(offset, len_); - int rc = fseek(fp_.get(), static_cast<long>(offset), SEEK_CUR); - if (rc == 0) len_ -= offset; - return rc; - } - std::string Version() const override { - // TODO: It would nice if the zoneinfo data included the tzdb version. - return std::string(); - } - - protected: - explicit FileZoneInfoSource( - FILE* fp, std::size_t len = std::numeric_limits<std::size_t>::max()) - : fp_(fp, fclose), len_(len) {} - - private: - std::unique_ptr<FILE, int (*)(FILE*)> fp_; - std::size_t len_; -}; - -std::unique_ptr<ZoneInfoSource> FileZoneInfoSource::Open( - const std::string& name) { - // Use of the "file:" prefix is intended for testing purposes only. - const std::size_t pos = (name.compare(0, 5, "file:") == 0) ? 5 : 0; - - // Map the time-zone name to a path name. - std::string path; - if (pos == name.size() || name[pos] != '/') { - const char* tzdir = "/usr/share/zoneinfo"; - char* tzdir_env = nullptr; -#if defined(_MSC_VER) - _dupenv_s(&tzdir_env, nullptr, "TZDIR"); -#else - tzdir_env = std::getenv("TZDIR"); -#endif - if (tzdir_env && *tzdir_env) tzdir = tzdir_env; - path += tzdir; - path += '/'; -#if defined(_MSC_VER) - free(tzdir_env); -#endif - } - path.append(name, pos, std::string::npos); - - // Open the zoneinfo file. - FILE* fp = FOpen(path.c_str(), "rb"); - if (fp == nullptr) return nullptr; - std::size_t length = 0; - if (fseek(fp, 0, SEEK_END) == 0) { - long offset = ftell(fp); - if (offset >= 0) { - length = static_cast<std::size_t>(offset); - } - rewind(fp); - } - return std::unique_ptr<ZoneInfoSource>(new FileZoneInfoSource(fp, length)); -} - -class AndroidZoneInfoSource : public FileZoneInfoSource { - public: - static std::unique_ptr<ZoneInfoSource> Open(const std::string& name); - std::string Version() const override { return version_; } - - private: - explicit AndroidZoneInfoSource(FILE* fp, std::size_t len, const char* vers) - : FileZoneInfoSource(fp, len), version_(vers) {} - std::string version_; -}; - -std::unique_ptr<ZoneInfoSource> AndroidZoneInfoSource::Open( - const std::string& name) { - // Use of the "file:" prefix is intended for testing purposes only. - const std::size_t pos = (name.compare(0, 5, "file:") == 0) ? 5 : 0; - - // See Android's libc/tzcode/bionic.cpp for additional information. - for (const char* tzdata : {"/data/misc/zoneinfo/current/tzdata", - "/system/usr/share/zoneinfo/tzdata"}) { - std::unique_ptr<FILE, int (*)(FILE*)> fp(FOpen(tzdata, "rb"), fclose); - if (fp.get() == nullptr) continue; - - char hbuf[24]; // covers header.zonetab_offset too - if (fread(hbuf, 1, sizeof(hbuf), fp.get()) != sizeof(hbuf)) continue; - if (strncmp(hbuf, "tzdata", 6) != 0) continue; - const char* vers = (hbuf[11] == '\0') ? hbuf + 6 : ""; - const std::int_fast32_t index_offset = Decode32(hbuf + 12); - const std::int_fast32_t data_offset = Decode32(hbuf + 16); - if (index_offset < 0 || data_offset < index_offset) continue; - if (fseek(fp.get(), static_cast<long>(index_offset), SEEK_SET) != 0) - continue; - - char ebuf[52]; // covers entry.unused too - const std::size_t index_size = - static_cast<std::size_t>(data_offset - index_offset); - const std::size_t zonecnt = index_size / sizeof(ebuf); - if (zonecnt * sizeof(ebuf) != index_size) continue; - for (std::size_t i = 0; i != zonecnt; ++i) { - if (fread(ebuf, 1, sizeof(ebuf), fp.get()) != sizeof(ebuf)) break; - const std::int_fast32_t start = data_offset + Decode32(ebuf + 40); - const std::int_fast32_t length = Decode32(ebuf + 44); - if (start < 0 || length < 0) break; - ebuf[40] = '\0'; // ensure zone name is NUL terminated - if (strcmp(name.c_str() + pos, ebuf) == 0) { - if (fseek(fp.get(), static_cast<long>(start), SEEK_SET) != 0) break; - return std::unique_ptr<ZoneInfoSource>(new AndroidZoneInfoSource( - fp.release(), static_cast<std::size_t>(length), vers)); - } - } - } - - return nullptr; -} - -} // namespace - bool TimeZoneInfo::Load(const std::string& name) { // We can ensure that the loading of UTC or any other fixed-offset // zone never fails because the simple, fixed-offset state can be @@ -728,11 +825,24 @@ bool TimeZoneInfo::Load(const std::string& name) { name, [](const std::string& n) -> std::unique_ptr<ZoneInfoSource> { if (auto z = FileZoneInfoSource::Open(n)) return z; if (auto z = AndroidZoneInfoSource::Open(n)) return z; + if (auto z = FuchsiaZoneInfoSource::Open(n)) return z; return nullptr; }); return zip != nullptr && Load(zip.get()); } +std::unique_ptr<TimeZoneInfo> TimeZoneInfo::UTC() { + auto tz = std::unique_ptr<TimeZoneInfo>(new TimeZoneInfo); + tz->ResetToBuiltinUTC(seconds::zero()); + return tz; +} + +std::unique_ptr<TimeZoneInfo> TimeZoneInfo::Make(const std::string& name) { + auto tz = std::unique_ptr<TimeZoneInfo>(new TimeZoneInfo); + if (!tz->Load(name)) tz.reset(); // fallback to UTC + return tz; +} + // BreakTime() translation for a particular transition type. time_zone::absolute_lookup TimeZoneInfo::LocalTime( std::int_fast64_t unix_time, const TransitionType& tt) const { |