From 2eba343b51e0923cd3fb919a6abd6120590fc059 Mon Sep 17 00:00:00 2001
From: Abseil Team <absl-team@google.com>
Date: Tue, 9 Jun 2020 08:17:12 -0700
Subject: [PATCH] Export of internal Abseil changes
--
baf626d27ff1547776745f3b601cc42f703d4bdf by Greg Falcon <gfalcon@google.com>:
Import of CCTZ from GitHub.
PiperOrigin-RevId: 315486679
--
39d4e7f9214c5a74e4ee4b8a7f4af26479925029 by Gennadiy Rozental <rogeeff@google.com>:
Avoid order dependant test cases.
PiperOrigin-RevId: 315327948
--
8feb187703a28bb0c5cfc5dd6091e3faa90a8e61 by Gennadiy Rozental <rogeeff@google.com>:
Avoid order dependant test cases.
PiperOrigin-RevId: 315317018
--
cffd8fddad15908ec9de7f21f65b20528972e3fa by Gennadiy Rozental <rogeeff@google.com>:
Avoid order dependant test cases.
PiperOrigin-RevId: 315311587
--
48997a0ceb231b75c14eb4b1eb3b66af69e49f42 by Tom Manshreck <shreck@google.com>:
Nit: remove extra "the"
PiperOrigin-RevId: 314959763
--
9516f44a4b5d3055427c95e80c8c04a6321e4221 by Gennadiy Rozental <rogeeff@google.com>:
Import of CCTZ from GitHub.
PiperOrigin-RevId: 314925147
--
4f8691d74a4eb42ed03ef29c9588a01b78829941 by Abseil Team <absl-team@google.com>:
Uninclude util/bits/bits.h
PiperOrigin-RevId: 314858384
--
02b42a8ec5e5561b29b4e5f93cc1482c3c72ef2d by Abseil Team <absl-team@google.com>:
Google-internal changes only.
PiperOrigin-RevId: 314855667
--
146013d69dabafbe2030e23ced7b741d9e8d417c by Gennadiy Rozental <rogeeff@google.com>:
Uninclude util/bits/bits.h
PiperOrigin-RevId: 314838927
GitOrigin-RevId: baf626d27ff1547776745f3b601cc42f703d4bdf
Change-Id: I2602286fb13cf35a88bdd80fe0b44974d4388d46
---
absl/base/internal/low_level_scheduling.h | 5 -
absl/flags/commandlineflag_test.cc | 12 +-
absl/flags/internal/program_name_test.cc | 4 +-
absl/flags/parse_test.cc | 4 +
absl/strings/str_format.h | 2 +-
absl/synchronization/mutex.cc | 7 -
.../internal/cctz/src/time_zone_format.cc | 124 ++++++++++++++----
.../cctz/src/time_zone_format_test.cc | 88 +++++++++++++
absl/time/internal/cctz/src/time_zone_impl.cc | 34 ++---
9 files changed, 215 insertions(+), 65 deletions(-)
diff --git a/absl/base/internal/low_level_scheduling.h b/absl/base/internal/low_level_scheduling.h
index 7c52d48c..961cc981 100644
--- a/absl/base/internal/low_level_scheduling.h
+++ b/absl/base/internal/low_level_scheduling.h
@@ -29,9 +29,6 @@ extern "C" void __google_enable_rescheduling(bool disable_result);
namespace absl {
ABSL_NAMESPACE_BEGIN
-class CondVar;
-class Mutex;
-
namespace base_internal {
class SchedulingHelper; // To allow use of SchedulingGuard.
@@ -80,8 +77,6 @@ class SchedulingGuard {
};
// Access to SchedulingGuard is explicitly white-listed.
- friend class absl::CondVar;
- friend class absl::Mutex;
friend class SchedulingHelper;
friend class SpinLock;
diff --git a/absl/flags/commandlineflag_test.cc b/absl/flags/commandlineflag_test.cc
index c5afff61..585db4ba 100644
--- a/absl/flags/commandlineflag_test.cc
+++ b/absl/flags/commandlineflag_test.cc
@@ -34,6 +34,10 @@ ABSL_FLAG(std::string, string_flag, "dflt",
absl::StrCat("string_flag", " help"));
ABSL_RETIRED_FLAG(bool, bool_retired_flag, false, "bool_retired_flag help");
+// These are only used to test default values.
+ABSL_FLAG(int, int_flag2, 201, "");
+ABSL_FLAG(std::string, string_flag2, "dflt", "");
+
namespace {
namespace flags = absl::flags_internal;
@@ -94,15 +98,15 @@ TEST_F(CommandLineFlagTest, TestAttributesAccessMethods) {
// --------------------------------------------------------------------
TEST_F(CommandLineFlagTest, TestValueAccessMethods) {
- absl::SetFlag(&FLAGS_int_flag, 301);
- auto* flag_01 = absl::FindCommandLineFlag("int_flag");
+ absl::SetFlag(&FLAGS_int_flag2, 301);
+ auto* flag_01 = absl::FindCommandLineFlag("int_flag2");
ASSERT_TRUE(flag_01);
EXPECT_EQ(flag_01->CurrentValue(), "301");
EXPECT_EQ(flag_01->DefaultValue(), "201");
- absl::SetFlag(&FLAGS_string_flag, "new_str_value");
- auto* flag_02 = absl::FindCommandLineFlag("string_flag");
+ absl::SetFlag(&FLAGS_string_flag2, "new_str_value");
+ auto* flag_02 = absl::FindCommandLineFlag("string_flag2");
ASSERT_TRUE(flag_02);
EXPECT_EQ(flag_02->CurrentValue(), "new_str_value");
diff --git a/absl/flags/internal/program_name_test.cc b/absl/flags/internal/program_name_test.cc
index 269142f2..aff9f631 100644
--- a/absl/flags/internal/program_name_test.cc
+++ b/absl/flags/internal/program_name_test.cc
@@ -25,7 +25,7 @@ namespace {
namespace flags = absl::flags_internal;
-TEST(FlagsPathUtilTest, TestInitialProgamName) {
+TEST(FlagsPathUtilTest, TestProgamNameInterfaces) {
flags::SetProgramInvocationName("absl/flags/program_name_test");
std::string program_name = flags::ProgramInvocationName();
for (char& c : program_name)
@@ -43,9 +43,7 @@ TEST(FlagsPathUtilTest, TestInitialProgamName) {
EXPECT_TRUE(absl::EndsWith(program_name, expect_name)) << program_name;
EXPECT_EQ(flags::ShortProgramInvocationName(), expect_basename);
-}
-TEST(FlagsPathUtilTest, TestProgamNameInterfaces) {
flags::SetProgramInvocationName("a/my_test");
EXPECT_EQ(flags::ProgramInvocationName(), "a/my_test");
diff --git a/absl/flags/parse_test.cc b/absl/flags/parse_test.cc
index 67ae8aad..d35a6e47 100644
--- a/absl/flags/parse_test.cc
+++ b/absl/flags/parse_test.cc
@@ -637,6 +637,10 @@ TEST_F(ParseTest, TestFlagfileInFlagfile) {
"--flagfile=$0/parse_test.ff2",
};
+ GetFlagfileFlag({{"parse_test.ff2", absl::MakeConstSpan(ff2_data)},
+ {"parse_test.ff1", absl::MakeConstSpan(ff1_data)}},
+ flagfile_flag);
+
const char* in_args1[] = {
"testbin",
GetFlagfileFlag({{"parse_test.ff3", absl::MakeConstSpan(ff3_data)}},
diff --git a/absl/strings/str_format.h b/absl/strings/str_format.h
index f833a80a..36bd84a3 100644
--- a/absl/strings/str_format.h
+++ b/absl/strings/str_format.h
@@ -19,7 +19,7 @@
//
// The `str_format` library is a typesafe replacement for the family of
// `printf()` string formatting routines within the `<cstdio>` standard library
-// header. Like the `printf` family, the `str_format` uses a "format string" to
+// header. Like the `printf` family, `str_format` uses a "format string" to
// perform argument substitutions based on types. See the `FormatSpec` section
// below for format string documentation.
//
diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc
index 36c93d5f..1f8a696e 100644
--- a/absl/synchronization/mutex.cc
+++ b/absl/synchronization/mutex.cc
@@ -58,7 +58,6 @@
using absl::base_internal::CurrentThreadIdentityIfPresent;
using absl::base_internal::PerThreadSynch;
-using absl::base_internal::SchedulingGuard;
using absl::base_internal::ThreadIdentity;
using absl::synchronization_internal::GetOrCreateCurrentThreadIdentity;
using absl::synchronization_internal::GraphCycles;
@@ -1109,7 +1108,6 @@ void Mutex::TryRemove(PerThreadSynch *s) {
// on the mutex queue. In this case, remove "s" from the queue and return
// true, otherwise return false.
ABSL_XRAY_LOG_ARGS(1) void Mutex::Block(PerThreadSynch *s) {
- SchedulingGuard::ScopedDisable disable_rescheduling;
while (s->state.load(std::memory_order_acquire) == PerThreadSynch::kQueued) {
if (!DecrementSynchSem(this, s, s->waitp->timeout)) {
// After a timeout, we go into a spin loop until we remove ourselves
@@ -1899,7 +1897,6 @@ static void CheckForMutexCorruption(intptr_t v, const char* label) {
}
void Mutex::LockSlowLoop(SynchWaitParams *waitp, int flags) {
- SchedulingGuard::ScopedDisable disable_rescheduling;
int c = 0;
intptr_t v = mu_.load(std::memory_order_relaxed);
if ((v & kMuEvent) != 0) {
@@ -2019,7 +2016,6 @@ void Mutex::LockSlowLoop(SynchWaitParams *waitp, int flags) {
// or it is in the process of blocking on a condition variable; it must requeue
// itself on the mutex/condvar to wait for its condition to become true.
ABSL_ATTRIBUTE_NOINLINE void Mutex::UnlockSlow(SynchWaitParams *waitp) {
- SchedulingGuard::ScopedDisable disable_rescheduling;
intptr_t v = mu_.load(std::memory_order_relaxed);
this->AssertReaderHeld();
CheckForMutexCorruption(v, "Unlock");
@@ -2335,7 +2331,6 @@ void Mutex::Trans(MuHow how) {
// It will later acquire the mutex with high probability. Otherwise, we
// enqueue thread w on this mutex.
void Mutex::Fer(PerThreadSynch *w) {
- SchedulingGuard::ScopedDisable disable_rescheduling;
int c = 0;
ABSL_RAW_CHECK(w->waitp->cond == nullptr,
"Mutex::Fer while waiting on Condition");
@@ -2434,7 +2429,6 @@ CondVar::~CondVar() {
// Remove thread s from the list of waiters on this condition variable.
void CondVar::Remove(PerThreadSynch *s) {
- SchedulingGuard::ScopedDisable disable_rescheduling;
intptr_t v;
int c = 0;
for (v = cv_.load(std::memory_order_relaxed);;
@@ -2595,7 +2589,6 @@ void CondVar::Wakeup(PerThreadSynch *w) {
}
void CondVar::Signal() {
- SchedulingGuard::ScopedDisable disable_rescheduling;
ABSL_TSAN_MUTEX_PRE_SIGNAL(nullptr, 0);
intptr_t v;
int c = 0;
diff --git a/absl/time/internal/cctz/src/time_zone_format.cc b/absl/time/internal/cctz/src/time_zone_format.cc
index a4428632..2e02233c 100644
--- a/absl/time/internal/cctz/src/time_zone_format.cc
+++ b/absl/time/internal/cctz/src/time_zone_format.cc
@@ -67,6 +67,48 @@ char* strptime(const char* s, const char* fmt, std::tm* tm) {
}
#endif
+// Convert a cctz::weekday to a tm_wday value (0-6, Sunday = 0).
+int ToTmWday(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*/
+}
+
+// Convert a tm_wday value (0-6, Sunday = 0) to a cctz::weekday.
+weekday FromTmWday(int tm_wday) {
+ switch (tm_wday) {
+ case 0:
+ return weekday::sunday;
+ case 1:
+ return weekday::monday;
+ case 2:
+ return weekday::tuesday;
+ case 3:
+ return weekday::wednesday;
+ case 4:
+ return weekday::thursday;
+ case 5:
+ return weekday::friday;
+ case 6:
+ return weekday::saturday;
+ }
+ return weekday::sunday; /*NOTREACHED*/
+}
+
std::tm ToTM(const time_zone::absolute_lookup& al) {
std::tm tm{};
tm.tm_sec = al.cs.second();
@@ -84,34 +126,19 @@ std::tm ToTM(const time_zone::absolute_lookup& al) {
tm.tm_year = static_cast<int>(al.cs.year() - 1900);
}
- switch (get_weekday(al.cs)) {
- case weekday::sunday:
- tm.tm_wday = 0;
- break;
- case weekday::monday:
- tm.tm_wday = 1;
- break;
- case weekday::tuesday:
- tm.tm_wday = 2;
- break;
- case weekday::wednesday:
- tm.tm_wday = 3;
- break;
- case weekday::thursday:
- tm.tm_wday = 4;
- break;
- case weekday::friday:
- tm.tm_wday = 5;
- break;
- case weekday::saturday:
- tm.tm_wday = 6;
- break;
- }
+ tm.tm_wday = ToTmWday(get_weekday(al.cs));
tm.tm_yday = get_yearday(al.cs) - 1;
tm.tm_isdst = al.is_dst ? 1 : 0;
return tm;
}
+// Returns the week of the year [0:53] given a civil day and the day on
+// which weeks are defined to start.
+int ToWeek(const civil_day& cd, weekday week_start) {
+ const civil_day d(cd.year() % 400, cd.month(), cd.day());
+ return static_cast<int>((d - prev_weekday(civil_year(d), week_start)) / 7);
+}
+
const char kDigits[] = "0123456789";
// Formats a 64-bit integer in the given field width. Note that it is up
@@ -355,7 +382,7 @@ std::string format(const std::string& format, const time_point<seconds>& tp,
if (cur == end || (cur - percent) % 2 == 0) continue;
// Simple specifiers that we handle ourselves.
- if (strchr("YmdeHMSzZs%", *cur)) {
+ if (strchr("YmdeUuWwHMSzZs%", *cur)) {
if (cur - 1 != pending) {
FormatTM(&result, std::string(pending, cur - 1), tm);
}
@@ -376,6 +403,22 @@ std::string format(const std::string& format, const time_point<seconds>& tp,
if (*cur == 'e' && *bp == '0') *bp = ' '; // for Windows
result.append(bp, static_cast<std::size_t>(ep - bp));
break;
+ case 'U':
+ bp = Format02d(ep, ToWeek(civil_day(al.cs), weekday::sunday));
+ result.append(bp, static_cast<std::size_t>(ep - bp));
+ break;
+ case 'u':
+ bp = Format64(ep, 0, tm.tm_wday ? tm.tm_wday : 7);
+ result.append(bp, static_cast<std::size_t>(ep - bp));
+ break;
+ case 'W':
+ bp = Format02d(ep, ToWeek(civil_day(al.cs), weekday::monday));
+ result.append(bp, static_cast<std::size_t>(ep - bp));
+ break;
+ case 'w':
+ bp = Format64(ep, 0, tm.tm_wday);
+ result.append(bp, static_cast<std::size_t>(ep - bp));
+ break;
case 'H':
bp = Format02d(ep, al.cs.hour());
result.append(bp, static_cast<std::size_t>(ep - bp));
@@ -610,6 +653,17 @@ const char* ParseTM(const char* dp, const char* fmt, std::tm* tm) {
return dp;
}
+// Sets year, tm_mon and tm_mday given the year, week_num, and tm_wday,
+// and the day on which weeks are defined to start.
+void FromWeek(int week_num, weekday week_start, year_t* year, std::tm* tm) {
+ const civil_year y(*year % 400);
+ civil_day cd = prev_weekday(y, week_start); // week 0
+ cd = next_weekday(cd - 1, FromTmWday(tm->tm_wday)) + (week_num * 7);
+ *year += cd.year() - y.year();
+ tm->tm_mon = cd.month() - 1;
+ tm->tm_mday = cd.day();
+}
+
} // namespace
// Uses strptime(3) to parse the given input. Supports the same extended
@@ -659,6 +713,8 @@ bool parse(const std::string& format, const std::string& input,
const char* fmt = format.c_str(); // NUL terminated
bool twelve_hour = false;
bool afternoon = false;
+ int week_num = -1;
+ weekday week_start = weekday::sunday;
bool saw_percent_s = false;
std::int_fast64_t percent_s = 0;
@@ -697,10 +753,27 @@ bool parse(const std::string& format, const std::string& input,
case 'm':
data = ParseInt(data, 2, 1, 12, &tm.tm_mon);
if (data != nullptr) tm.tm_mon -= 1;
+ week_num = -1;
continue;
case 'd':
case 'e':
data = ParseInt(data, 2, 1, 31, &tm.tm_mday);
+ week_num = -1;
+ continue;
+ case 'U':
+ data = ParseInt(data, 0, 0, 53, &week_num);
+ week_start = weekday::sunday;
+ continue;
+ case 'W':
+ data = ParseInt(data, 0, 0, 53, &week_num);
+ week_start = weekday::monday;
+ continue;
+ case 'u':
+ data = ParseInt(data, 0, 1, 7, &tm.tm_wday);
+ if (data != nullptr) tm.tm_wday %= 7;
+ continue;
+ case 'w':
+ data = ParseInt(data, 0, 0, 6, &tm.tm_wday);
continue;
case 'H':
data = ParseInt(data, 2, 0, 23, &tm.tm_hour);
@@ -891,6 +964,9 @@ bool parse(const std::string& format, const std::string& input,
year += 1900;
}
+ // Compute year, tm.tm_mon and tm.tm_mday if we parsed a week number.
+ if (week_num != -1) FromWeek(week_num, week_start, &year, &tm);
+
const int month = tm.tm_mon + 1;
civil_second cs(year, month, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
diff --git a/absl/time/internal/cctz/src/time_zone_format_test.cc b/absl/time/internal/cctz/src/time_zone_format_test.cc
index 13a4227e..e625a839 100644
--- a/absl/time/internal/cctz/src/time_zone_format_test.cc
+++ b/absl/time/internal/cctz/src/time_zone_format_test.cc
@@ -679,6 +679,34 @@ TEST(Format, RFC1123Format) { // locale specific
EXPECT_EQ("28 Jun 1977 09:08:07 -0700", format(RFC1123_no_wday, tp, tz));
}
+TEST(Format, Week) {
+ const time_zone utc = utc_time_zone();
+
+ auto tp = convert(civil_second(2017, 1, 1, 0, 0, 0), utc);
+ EXPECT_EQ("2017-01-7", format("%Y-%U-%u", tp, utc));
+ EXPECT_EQ("2017-00-0", format("%Y-%W-%w", tp, utc));
+
+ tp = convert(civil_second(2017, 12, 31, 0, 0, 0), utc);
+ EXPECT_EQ("2017-53-7", format("%Y-%U-%u", tp, utc));
+ EXPECT_EQ("2017-52-0", format("%Y-%W-%w", tp, utc));
+
+ tp = convert(civil_second(2018, 1, 1, 0, 0, 0), utc);
+ EXPECT_EQ("2018-00-1", format("%Y-%U-%u", tp, utc));
+ EXPECT_EQ("2018-01-1", format("%Y-%W-%w", tp, utc));
+
+ tp = convert(civil_second(2018, 12, 31, 0, 0, 0), utc);
+ EXPECT_EQ("2018-52-1", format("%Y-%U-%u", tp, utc));
+ EXPECT_EQ("2018-53-1", format("%Y-%W-%w", tp, utc));
+
+ tp = convert(civil_second(2019, 1, 1, 0, 0, 0), utc);
+ EXPECT_EQ("2019-00-2", format("%Y-%U-%u", tp, utc));
+ EXPECT_EQ("2019-00-2", format("%Y-%W-%w", tp, utc));
+
+ tp = convert(civil_second(2019, 12, 31, 0, 0, 0), utc);
+ EXPECT_EQ("2019-52-2", format("%Y-%U-%u", tp, utc));
+ EXPECT_EQ("2019-52-2", format("%Y-%W-%w", tp, utc));
+}
+
//
// Testing parse()
//
@@ -1395,6 +1423,66 @@ TEST(Parse, RFC3339Format) {
EXPECT_EQ(tp, tp4);
}
+TEST(Parse, Week) {
+ const time_zone utc = utc_time_zone();
+ time_point<absl::time_internal::cctz::seconds> tp;
+
+ auto exp = convert(civil_second(2017, 1, 1, 0, 0, 0), utc);
+ EXPECT_TRUE(parse("%Y-%U-%u", "2017-01-7", utc, &tp));
+ EXPECT_EQ(exp, tp);
+ EXPECT_TRUE(parse("%Y-%W-%w", "2017-00-0", utc, &tp));
+ EXPECT_EQ(exp, tp);
+
+ exp = convert(civil_second(2017, 12, 31, 0, 0, 0), utc);
+ EXPECT_TRUE(parse("%Y-%U-%u", "2017-53-7", utc, &tp));
+ EXPECT_EQ(exp, tp);
+ EXPECT_TRUE(parse("%Y-%W-%w", "2017-52-0", utc, &tp));
+ EXPECT_EQ(exp, tp);
+
+ exp = convert(civil_second(2018, 1, 1, 0, 0, 0), utc);
+ EXPECT_TRUE(parse("%Y-%U-%u", "2018-00-1", utc, &tp));
+ EXPECT_EQ(exp, tp);
+ EXPECT_TRUE(parse("%Y-%W-%w", "2018-01-1", utc, &tp));
+ EXPECT_EQ(exp, tp);
+
+ exp = convert(civil_second(2018, 12, 31, 0, 0, 0), utc);
+ EXPECT_TRUE(parse("%Y-%U-%u", "2018-52-1", utc, &tp));
+ EXPECT_EQ(exp, tp);
+ EXPECT_TRUE(parse("%Y-%W-%w", "2018-53-1", utc, &tp));
+ EXPECT_EQ(exp, tp);
+
+ exp = convert(civil_second(2019, 1, 1, 0, 0, 0), utc);
+ EXPECT_TRUE(parse("%Y-%U-%u", "2019-00-2", utc, &tp));
+ EXPECT_EQ(exp, tp);
+ EXPECT_TRUE(parse("%Y-%W-%w", "2019-00-2", utc, &tp));
+ EXPECT_EQ(exp, tp);
+
+ exp = convert(civil_second(2019, 12, 31, 0, 0, 0), utc);
+ EXPECT_TRUE(parse("%Y-%U-%u", "2019-52-2", utc, &tp));
+ EXPECT_EQ(exp, tp);
+ EXPECT_TRUE(parse("%Y-%W-%w", "2019-52-2", utc, &tp));
+ EXPECT_EQ(exp, tp);
+}
+
+TEST(Parse, WeekYearShift) {
+ // %U/%W conversions with week values in {0, 52, 53} can slip
+ // into the previous/following calendar years.
+ const time_zone utc = utc_time_zone();
+ time_point<absl::time_internal::cctz::seconds> tp;
+
+ auto exp = convert(civil_second(2019, 12, 31, 0, 0, 0), utc);
+ EXPECT_TRUE(parse("%Y-%U-%u", "2020-00-2", utc, &tp));
+ EXPECT_EQ(exp, tp);
+ EXPECT_TRUE(parse("%Y-%W-%w", "2020-00-2", utc, &tp));
+ EXPECT_EQ(exp, tp);
+
+ exp = convert(civil_second(2021, 1, 1, 0, 0, 0), utc);
+ EXPECT_TRUE(parse("%Y-%U-%u", "2020-52-5", utc, &tp));
+ EXPECT_EQ(exp, tp);
+ EXPECT_TRUE(parse("%Y-%W-%w", "2020-52-5", utc, &tp));
+ EXPECT_EQ(exp, tp);
+}
+
TEST(Parse, MaxRange) {
const time_zone utc = utc_time_zone();
time_point<absl::time_internal::cctz::seconds> tp;
diff --git a/absl/time/internal/cctz/src/time_zone_impl.cc b/absl/time/internal/cctz/src/time_zone_impl.cc
index 030ae0e1..f34e3aec 100644
--- a/absl/time/internal/cctz/src/time_zone_impl.cc
+++ b/absl/time/internal/cctz/src/time_zone_impl.cc
@@ -15,6 +15,7 @@
#include "time_zone_impl.h"
#include <deque>
+#include <memory>
#include <mutex>
#include <string>
#include <unordered_map>
@@ -48,17 +49,16 @@ std::mutex& TimeZoneMutex() {
time_zone time_zone::Impl::UTC() { return time_zone(UTCImpl()); }
bool time_zone::Impl::LoadTimeZone(const std::string& name, time_zone* tz) {
- const time_zone::Impl* const utc_impl = UTCImpl();
+ const Impl* const utc_impl = UTCImpl();
- // First check for UTC (which is never a key in time_zone_map).
+ // Check for UTC (which is never a key in time_zone_map).
auto offset = seconds::zero();
if (FixedOffsetFromName(name, &offset) && offset == seconds::zero()) {
*tz = time_zone(utc_impl);
return true;
}
- // Then check, under a shared lock, whether the time zone has already
- // been loaded. This is the common path. TODO: Move to shared_mutex.
+ // Check whether the time zone has already been loaded.
{
std::lock_guard<std::mutex> lock(TimeZoneMutex());
if (time_zone_map != nullptr) {
@@ -70,20 +70,15 @@ bool time_zone::Impl::LoadTimeZone(const std::string& name, time_zone* tz) {
}
}
- // Now check again, under an exclusive lock.
+ // Load the new time zone (outside the lock).
+ std::unique_ptr<const Impl> new_impl(new Impl(name));
+
+ // Add the new time zone to the map.
std::lock_guard<std::mutex> lock(TimeZoneMutex());
if (time_zone_map == nullptr) time_zone_map = new TimeZoneImplByName;
const Impl*& impl = (*time_zone_map)[name];
- if (impl == nullptr) {
- // The first thread in loads the new time zone.
- Impl* new_impl = new Impl(name);
- new_impl->zone_ = TimeZoneIf::Load(new_impl->name_);
- if (new_impl->zone_ == nullptr) {
- delete new_impl; // free the nascent Impl
- impl = utc_impl; // and fallback to UTC
- } else {
- impl = new_impl; // install new time zone
- }
+ if (impl == nullptr) { // this thread won any load race
+ impl = new_impl->zone_ ? new_impl.release() : utc_impl;
}
*tz = time_zone(impl);
return impl != utc_impl;
@@ -104,14 +99,11 @@ void time_zone::Impl::ClearTimeZoneMapTestOnly() {
}
}
-time_zone::Impl::Impl(const std::string& name) : name_(name) {}
+time_zone::Impl::Impl(const std::string& name)
+ : name_(name), zone_(TimeZoneIf::Load(name_)) {}
const time_zone::Impl* time_zone::Impl::UTCImpl() {
- static Impl* utc_impl = [] {
- Impl* impl = new Impl("UTC");
- impl->zone_ = TimeZoneIf::Load(impl->name_); // never fails
- return impl;
- }();
+ static const Impl* utc_impl = new Impl("UTC"); // never fails
return utc_impl;
}