diff options
| -rw-r--r-- | CMake/AbseilDll.cmake | 1 | ||||
| -rw-r--r-- | absl/synchronization/BUILD.bazel | 16 | ||||
| -rw-r--r-- | absl/synchronization/CMakeLists.txt | 18 | ||||
| -rw-r--r-- | absl/synchronization/internal/kernel_timeout.cc | 168 | ||||
| -rw-r--r-- | absl/synchronization/internal/kernel_timeout.h | 180 | ||||
| -rw-r--r-- | absl/synchronization/internal/kernel_timeout_test.cc | 278 |
6 files changed, 546 insertions, 115 deletions
diff --git a/CMake/AbseilDll.cmake b/CMake/AbseilDll.cmake index 52a563cd..3c0f6901 100644 --- a/CMake/AbseilDll.cmake +++ b/CMake/AbseilDll.cmake @@ -365,6 +365,7 @@ set(ABSL_INTERNAL_DLL_FILES "synchronization/internal/graphcycles.cc" "synchronization/internal/graphcycles.h" "synchronization/internal/kernel_timeout.h" + "synchronization/internal/kernel_timeout.cc" "synchronization/internal/per_thread_sem.cc" "synchronization/internal/per_thread_sem.h" "synchronization/internal/thread_pool.h" diff --git a/absl/synchronization/BUILD.bazel b/absl/synchronization/BUILD.bazel index ccaee796..9c89ac49 100644 --- a/absl/synchronization/BUILD.bazel +++ b/absl/synchronization/BUILD.bazel @@ -53,6 +53,7 @@ cc_library( cc_library( name = "kernel_timeout_internal", + srcs = ["internal/kernel_timeout.cc"], hdrs = ["internal/kernel_timeout.h"], copts = ABSL_DEFAULT_COPTS, linkopts = ABSL_DEFAULT_LINKOPTS, @@ -60,12 +61,25 @@ cc_library( "//absl/synchronization:__pkg__", ], deps = [ - "//absl/base:core_headers", + "//absl/base:config", "//absl/base:raw_logging_internal", "//absl/time", ], ) +cc_test( + name = "kernel_timeout_internal_test", + srcs = ["internal/kernel_timeout_test.cc"], + copts = ABSL_TEST_COPTS, + linkopts = ABSL_DEFAULT_LINKOPTS, + deps = [ + ":kernel_timeout_internal", + "//absl/base:config", + "//absl/time", + "@com_google_googletest//:gtest_main", + ], +) + cc_library( name = "synchronization", srcs = [ diff --git a/absl/synchronization/CMakeLists.txt b/absl/synchronization/CMakeLists.txt index f64653bb..5eb9b566 100644 --- a/absl/synchronization/CMakeLists.txt +++ b/absl/synchronization/CMakeLists.txt @@ -39,14 +39,30 @@ absl_cc_library( kernel_timeout_internal HDRS "internal/kernel_timeout.h" + SRCS + "internal/kernel_timeout.cc" COPTS ${ABSL_DEFAULT_COPTS} DEPS - absl::core_headers + absl::config absl::raw_logging_internal absl::time ) +absl_cc_test( + NAME + kernel_timeout_internal_test + SRCS + "internal/kernel_timeout_test.cc" + COPTS + ${ABSL_TEST_COPTS} + DEPS + absl::kernel_timeout_internal + absl::config + absl::time + GTest::gmock_main +) + absl_cc_library( NAME synchronization diff --git a/absl/synchronization/internal/kernel_timeout.cc b/absl/synchronization/internal/kernel_timeout.cc new file mode 100644 index 00000000..4015bd0c --- /dev/null +++ b/absl/synchronization/internal/kernel_timeout.cc @@ -0,0 +1,168 @@ +// Copyright 2023 The Abseil Authors +// +// 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 +// +// https://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. + +#include "absl/synchronization/internal/kernel_timeout.h" + +#include <algorithm> +#include <cstdint> +#include <ctime> +#include <limits> + +#include "absl/base/config.h" +#include "absl/time/time.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace synchronization_internal { + +#ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL +constexpr uint64_t KernelTimeout::kNoTimeout; +constexpr int64_t KernelTimeout::kMaxNanos; +#endif + +KernelTimeout::KernelTimeout(absl::Time t) { + // `absl::InfiniteFuture()` is a common "no timeout" value and cheaper to + // compare than convert. + if (t == absl::InfiniteFuture()) { + rep_ = kNoTimeout; + return; + } + + int64_t unix_nanos = absl::ToUnixNanos(t); + + // A timeout that lands before the unix epoch is converted to 0. + // In theory implementations should expire these timeouts immediately. + if (unix_nanos < 0) { + unix_nanos = 0; + } + + // Values greater than or equal to kMaxNanos are converted to infinite. + if (unix_nanos >= kMaxNanos) { + rep_ = kNoTimeout; + return; + } + + rep_ = static_cast<uint64_t>(unix_nanos) << 1; +} + +KernelTimeout::KernelTimeout(absl::Duration d) { + // `absl::InfiniteDuration()` is a common "no timeout" value and cheaper to + // compare than convert. + if (d == absl::InfiniteDuration()) { + rep_ = kNoTimeout; + return; + } + + int64_t nanos = absl::ToInt64Nanoseconds(d); + + // Negative durations are normalized to 0. + // In theory implementations should expire these timeouts immediately. + if (nanos < 0) { + nanos = 0; + } + + // Values greater than or equal to kMaxNanos are converted to infinite. + if (nanos >= kMaxNanos) { + rep_ = kNoTimeout; + return; + } + + rep_ = (static_cast<uint64_t>(nanos) << 1) | uint64_t{1}; +} + +int64_t KernelTimeout::MakeAbsNanos() const { + if (!has_timeout()) { + return kMaxNanos; + } + + int64_t nanos = RawNanos(); + + if (is_relative_timeout()) { + int64_t now = ToUnixNanos(absl::Now()); + if (nanos > kMaxNanos - now) { + // Overflow. + nanos = kMaxNanos; + } else { + nanos += now; + } + } else if (nanos == 0) { + // Some callers have assumed that 0 means no timeout, so instead we return a + // time of 1 nanosecond after the epoch. + nanos = 1; + } + + return nanos; +} + +struct timespec KernelTimeout::MakeAbsTimespec() const { + return absl::ToTimespec(absl::Nanoseconds(MakeAbsNanos())); +} + +struct timespec KernelTimeout::MakeRelativeTimespec() const { + if (!has_timeout()) { + return absl::ToTimespec(absl::Nanoseconds(kMaxNanos)); + } + if (is_relative_timeout()) { + return absl::ToTimespec(absl::Nanoseconds(RawNanos())); + } + + int64_t nanos = RawNanos(); + int64_t now = ToUnixNanos(absl::Now()); + if (now > nanos) { + // Convert past values to 0 to be safe. + nanos = 0; + } else { + nanos -= now; + } + return absl::ToTimespec(absl::Nanoseconds(nanos)); +} + +KernelTimeout::DWord KernelTimeout::InMillisecondsFromNow() const { + constexpr DWord kInfinite = std::numeric_limits<DWord>::max(); + + if (!has_timeout()) { + return kInfinite; + } + + const int64_t nanos = RawNanos(); + constexpr uint64_t kNanosInMillis = uint64_t{1000000}; + + if (is_relative_timeout()) { + uint64_t ms = static_cast<uint64_t>(nanos) / kNanosInMillis; + if (ms > static_cast<uint64_t>(kInfinite)) { + ms = static_cast<uint64_t>(kInfinite); + } + return static_cast<DWord>(ms); + } + + int64_t now = ToUnixNanos(absl::Now()); + if (nanos >= now) { + // Round up so that now + ms_from_now >= nanos. + constexpr uint64_t kMaxValueNanos = + std::numeric_limits<int64_t>::max() - kNanosInMillis + 1; + uint64_t ms_from_now = + (std::min(kMaxValueNanos, static_cast<uint64_t>(nanos - now)) + + kNanosInMillis - 1) / + kNanosInMillis; + if (ms_from_now > kInfinite) { + return kInfinite; + } + return static_cast<DWord>(ms_from_now); + } + return DWord{0}; +} + +} // namespace synchronization_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/absl/synchronization/internal/kernel_timeout.h b/absl/synchronization/internal/kernel_timeout.h index f5c2c0ef..1f4d82cd 100644 --- a/absl/synchronization/internal/kernel_timeout.h +++ b/absl/synchronization/internal/kernel_timeout.h @@ -11,26 +11,16 @@ // 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. -// - -// An optional absolute timeout, with nanosecond granularity, -// compatible with absl::Time. Suitable for in-register -// parameter-passing (e.g. syscalls.) -// Constructible from a absl::Time (for a timeout to be respected) or {} -// (for "no timeout".) -// This is a private low-level API for use by a handful of low-level -// components. Higher-level components should build APIs based on -// absl::Time and absl::Duration. #ifndef ABSL_SYNCHRONIZATION_INTERNAL_KERNEL_TIMEOUT_H_ #define ABSL_SYNCHRONIZATION_INTERNAL_KERNEL_TIMEOUT_H_ -#include <time.h> - #include <algorithm> #include <cstdint> +#include <ctime> #include <limits> +#include "absl/base/config.h" #include "absl/base/internal/raw_logging.h" #include "absl/time/clock.h" #include "absl/time/time.h" @@ -41,56 +31,59 @@ namespace synchronization_internal { class Waiter; +// An optional timeout, with nanosecond granularity. +// +// This is a private low-level API for use by a handful of low-level +// components. Higher-level components should build APIs based on +// absl::Time and absl::Duration. class KernelTimeout { public: - // A timeout that should expire at <t>. Any value, in the full - // InfinitePast() to InfiniteFuture() range, is valid here and will be - // respected. - explicit KernelTimeout(absl::Time t) : ns_(MakeNs(t)) {} - // No timeout. - KernelTimeout() : ns_(0) {} + // Construct an absolute timeout that should expire at `t`. + explicit KernelTimeout(absl::Time t); + + // Construct a relative timeout that should expire after `d`. + explicit KernelTimeout(absl::Duration d); + + // Infinite timeout. + constexpr KernelTimeout() : rep_(kNoTimeout) {} + + // A more explicit factory for those who prefer it. + // Equivalent to `KernelTimeout()`. + static constexpr KernelTimeout Never() { return KernelTimeout(); } - // A more explicit factory for those who prefer it. Equivalent to {}. - static KernelTimeout Never() { return {}; } + // Returns true if there is a timeout that will eventually expire. + // Returns false if the timeout is infinite. + bool has_timeout() const { return rep_ != kNoTimeout; } - // We explicitly do not support other custom formats: timespec, int64_t nanos. - // Unify on this and absl::Time, please. + // If `has_timeout()` is true, returns true if the timeout was provided as an + // `absl::Time`. The return value is undefined if `has_timeout()` is false + // because all indefinite timeouts are equivalent. + bool is_absolute_timeout() const { return (rep_ & 1) == 0; } - bool has_timeout() const { return ns_ != 0; } + // If `has_timeout()` is true, returns true if the timeout was provided as an + // `absl::Duration`. The return value is undefined if `has_timeout()` is false + // because all indefinite timeouts are equivalent. + bool is_relative_timeout() const { return (rep_ & 1) == 1; } - // Convert to parameter for sem_timedwait/futex/similar. Only for approved - // users. Do not call if !has_timeout. + // Convert to `struct timespec` for interfaces that expect an absolute + // timeout. If !has_timeout() or is_relative_timeout(), attempts to convert to + // a reasonable absolute timeout, but callers should to test has_timeout() and + // is_relative_timeout() and prefer to use a more appropriate interface. struct timespec MakeAbsTimespec() const; - // Convert to unix epoch nanos. Do not call if !has_timeout. + // Convert to `struct timespec` for interfaces that expect a relative + // timeout. If !has_timeout() or is_absolute_timeout(), attempts to convert to + // a reasonable relative timeout, but callers should to test has_timeout() and + // is_absolute_timeout() and prefer to use a more appropriate interface. + struct timespec MakeRelativeTimespec() const; + + // Convert to unix epoch nanos for interfaces that expect an absolute timeout + // in nanoseconds. If !has_timeout() or is_relative_timeout(), attempts to + // convert to a reasonable absolute timeout, but callers should to test + // has_timeout() and is_relative_timeout() and prefer to use a more + // appropriate interface. int64_t MakeAbsNanos() const; - private: - // internal rep, not user visible: ns after unix epoch. - // zero = no timeout. - // Negative we treat as an unlikely (and certainly expired!) but valid - // timeout. - int64_t ns_; - - static int64_t MakeNs(absl::Time t) { - // optimization--InfiniteFuture is common "no timeout" value - // and cheaper to compare than convert. - if (t == absl::InfiniteFuture()) return 0; - int64_t x = ToUnixNanos(t); - - // A timeout that lands exactly on the epoch (x=0) needs to be respected, - // so we alter it unnoticably to 1. Negative timeouts are in - // theory supported, but handled poorly by the kernel (long - // delays) so push them forward too; since all such times have - // already passed, it's indistinguishable. - if (x <= 0) x = 1; - // A time larger than what can be represented to the kernel is treated - // as no timeout. - if (x == (std::numeric_limits<int64_t>::max)()) x = 0; - return x; - } - -#ifdef _WIN32 // Converts to milliseconds from now, or INFINITE when // !has_timeout(). For use by SleepConditionVariableSRW on // Windows. Callers should recognize that the return value is a @@ -100,68 +93,29 @@ class KernelTimeout { // so we define our own DWORD and INFINITE instead of getting them from // <intsafe.h> and <WinBase.h>. typedef unsigned long DWord; // NOLINT - DWord InMillisecondsFromNow() const { - constexpr DWord kInfinite = (std::numeric_limits<DWord>::max)(); - if (!has_timeout()) { - return kInfinite; - } - // The use of absl::Now() to convert from absolute time to - // relative time means that absl::Now() cannot use anything that - // depends on KernelTimeout (for example, Mutex) on Windows. - int64_t now = ToUnixNanos(absl::Now()); - if (ns_ >= now) { - // Round up so that Now() + ms_from_now >= ns_. - constexpr uint64_t max_nanos = - (std::numeric_limits<int64_t>::max)() - 999999u; - uint64_t ms_from_now = - ((std::min)(max_nanos, static_cast<uint64_t>(ns_ - now)) + 999999u) / - 1000000u; - if (ms_from_now > kInfinite) { - return kInfinite; - } - return static_cast<DWord>(ms_from_now); - } - return 0; - } - - friend class Waiter; -#endif -}; + DWord InMillisecondsFromNow() const; -inline struct timespec KernelTimeout::MakeAbsTimespec() const { - int64_t n = ns_; - static const int64_t kNanosPerSecond = 1000 * 1000 * 1000; - if (n == 0) { - ABSL_RAW_LOG( - ERROR, "Tried to create a timespec from a non-timeout; never do this."); - // But we'll try to continue sanely. no-timeout ~= saturated timeout. - n = (std::numeric_limits<int64_t>::max)(); - } - - // Kernel APIs validate timespecs as being at or after the epoch, - // despite the kernel time type being signed. However, no one can - // tell the difference between a timeout at or before the epoch (since - // all such timeouts have expired!) - if (n < 0) n = 0; - - struct timespec abstime; - int64_t seconds = (std::min)(n / kNanosPerSecond, - int64_t{(std::numeric_limits<time_t>::max)()}); - abstime.tv_sec = static_cast<time_t>(seconds); - abstime.tv_nsec = static_cast<decltype(abstime.tv_nsec)>(n % kNanosPerSecond); - return abstime; -} - -inline int64_t KernelTimeout::MakeAbsNanos() const { - if (ns_ == 0) { - ABSL_RAW_LOG( - ERROR, "Tried to create a timeout from a non-timeout; never do this."); - // But we'll try to continue sanely. no-timeout ~= saturated timeout. - return (std::numeric_limits<int64_t>::max)(); - } - - return ns_; -} + private: + // Internal representation. + // - If the value is kNoTimeout, then the timeout is infinite, and + // has_timeout() will return true. + // - If the low bit is 0, then the high 63 bits is number of nanoseconds + // after the unix epoch. + // - If the low bit is 1, then the high 63 bits is a relative duration in + // nanoseconds. + uint64_t rep_; + + // Returns the number of nanoseconds stored in the internal representation. + // Together with is_absolute_timeout() and is_relative_timeout(), the return + // value is used to compute when the timeout should occur. + int64_t RawNanos() const { return static_cast<int64_t>(rep_ >> 1); } + + // A value that represents no timeout (or an infinite timeout). + static constexpr uint64_t kNoTimeout = (std::numeric_limits<uint64_t>::max)(); + + // The maximum value that can be stored in the high 63 bits. + static constexpr int64_t kMaxNanos = (std::numeric_limits<int64_t>::max)(); +}; } // namespace synchronization_internal ABSL_NAMESPACE_END diff --git a/absl/synchronization/internal/kernel_timeout_test.cc b/absl/synchronization/internal/kernel_timeout_test.cc new file mode 100644 index 00000000..a89ae220 --- /dev/null +++ b/absl/synchronization/internal/kernel_timeout_test.cc @@ -0,0 +1,278 @@ +// Copyright 2023 The Abseil Authors +// +// 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 +// +// https://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. + +#include "absl/synchronization/internal/kernel_timeout.h" + +#include <limits> + +#include "gtest/gtest.h" +#include "absl/base/config.h" +#include "absl/time/clock.h" +#include "absl/time/time.h" + +namespace { + +#if defined(ABSL_HAVE_ADDRESS_SANITIZER) || \ + defined(ABSL_HAVE_MEMORY_SANITIZER) || \ + defined(ABSL_HAVE_THREAD_SANITIZER) || defined(__ANDROID__) +constexpr absl::Duration kTimingBound = absl::Milliseconds(5); +#else +constexpr absl::Duration kTimingBound = absl::Microseconds(250); +#endif + +using absl::synchronization_internal::KernelTimeout; + +TEST(KernelTimeout, FiniteTimes) { + constexpr absl::Duration kDurationsToTest[] = { + absl::ZeroDuration(), + absl::Nanoseconds(1), + absl::Microseconds(1), + absl::Milliseconds(1), + absl::Seconds(1), + absl::Minutes(1), + absl::Hours(1), + absl::Hours(1000), + -absl::Nanoseconds(1), + -absl::Microseconds(1), + -absl::Milliseconds(1), + -absl::Seconds(1), + -absl::Minutes(1), + -absl::Hours(1), + -absl::Hours(1000), + }; + + for (auto duration : kDurationsToTest) { + const absl::Time now = absl::Now(); + const absl::Time when = now + duration; + SCOPED_TRACE(duration); + KernelTimeout t(when); + EXPECT_TRUE(t.has_timeout()); + EXPECT_TRUE(t.is_absolute_timeout()); + EXPECT_FALSE(t.is_relative_timeout()); + EXPECT_EQ(absl::TimeFromTimespec(t.MakeAbsTimespec()), when); + // MakeRelativeTimespec() doesn't quite round trip when using an absolute + // time, but it should get pretty close. Past times are converted to zero + // durations. + EXPECT_LE( + absl::AbsDuration(absl::DurationFromTimespec(t.MakeRelativeTimespec()) - + std::max(duration, absl::ZeroDuration())), + kTimingBound); + EXPECT_EQ(absl::FromUnixNanos(t.MakeAbsNanos()), when); + EXPECT_LE(absl::AbsDuration(absl::Milliseconds(t.InMillisecondsFromNow()) - + std::max(duration, absl::ZeroDuration())), + absl::Milliseconds(5)); + } +} + +TEST(KernelTimeout, InfiniteFuture) { + KernelTimeout t(absl::InfiniteFuture()); + EXPECT_FALSE(t.has_timeout()); + // Callers are expected to check has_timeout() instead of using the methods + // below, but we do try to do something reasonable if they don't. We may not + // be able to round-trip back to absl::InfiniteDuration() or + // absl::InfiniteFuture(), but we should return a very large value. + EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), + absl::Now() + absl::Hours(100000)); + EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), + absl::Hours(100000)); + EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), + absl::Now() + absl::Hours(100000)); + EXPECT_EQ(t.InMillisecondsFromNow(), + std::numeric_limits<KernelTimeout::DWord>::max()); +} + +TEST(KernelTimeout, DefaultConstructor) { + // The default constructor is equivalent to absl::InfiniteFuture(). + KernelTimeout t; + EXPECT_FALSE(t.has_timeout()); + // Callers are expected to check has_timeout() instead of using the methods + // below, but we do try to do something reasonable if they don't. We may not + // be able to round-trip back to absl::InfiniteDuration() or + // absl::InfiniteFuture(), but we should return a very large value. + EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), + absl::Now() + absl::Hours(100000)); + EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), + absl::Hours(100000)); + EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), + absl::Now() + absl::Hours(100000)); + EXPECT_EQ(t.InMillisecondsFromNow(), + std::numeric_limits<KernelTimeout::DWord>::max()); +} + +TEST(KernelTimeout, TimeMaxNanos) { + // Time >= kMaxNanos should behave as no timeout. + KernelTimeout t(absl::FromUnixNanos(std::numeric_limits<int64_t>::max())); + EXPECT_FALSE(t.has_timeout()); + // Callers are expected to check has_timeout() instead of using the methods + // below, but we do try to do something reasonable if they don't. We may not + // be able to round-trip back to absl::InfiniteDuration() or + // absl::InfiniteFuture(), but we should return a very large value. + EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), + absl::Now() + absl::Hours(100000)); + EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), + absl::Hours(100000)); + EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), + absl::Now() + absl::Hours(100000)); + EXPECT_EQ(t.InMillisecondsFromNow(), + std::numeric_limits<KernelTimeout::DWord>::max()); +} + +TEST(KernelTimeout, Never) { + // KernelTimeout::Never() is equivalent to absl::InfiniteFuture(). + KernelTimeout t = KernelTimeout::Never(); + EXPECT_FALSE(t.has_timeout()); + // Callers are expected to check has_timeout() instead of using the methods + // below, but we do try to do something reasonable if they don't. We may not + // be able to round-trip back to absl::InfiniteDuration() or + // absl::InfiniteFuture(), but we should return a very large value. + EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), + absl::Now() + absl::Hours(100000)); + EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), + absl::Hours(100000)); + EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), + absl::Now() + absl::Hours(100000)); + EXPECT_EQ(t.InMillisecondsFromNow(), + std::numeric_limits<KernelTimeout::DWord>::max()); +} + +TEST(KernelTimeout, InfinitePast) { + KernelTimeout t(absl::InfinitePast()); + EXPECT_TRUE(t.has_timeout()); + EXPECT_TRUE(t.is_absolute_timeout()); + EXPECT_FALSE(t.is_relative_timeout()); + EXPECT_LE(absl::TimeFromTimespec(t.MakeAbsTimespec()), + absl::FromUnixNanos(1)); + EXPECT_EQ(absl::DurationFromTimespec(t.MakeRelativeTimespec()), + absl::ZeroDuration()); + EXPECT_LE(absl::FromUnixNanos(t.MakeAbsNanos()), absl::FromUnixNanos(1)); + EXPECT_EQ(t.InMillisecondsFromNow(), KernelTimeout::DWord{0}); +} + +TEST(KernelTimeout, FiniteDurations) { + constexpr absl::Duration kDurationsToTest[] = { + absl::ZeroDuration(), + absl::Nanoseconds(1), + absl::Microseconds(1), + absl::Milliseconds(1), + absl::Seconds(1), + absl::Minutes(1), + absl::Hours(1), + absl::Hours(1000), + }; + + for (auto duration : kDurationsToTest) { + SCOPED_TRACE(duration); + KernelTimeout t(duration); + EXPECT_TRUE(t.has_timeout()); + EXPECT_FALSE(t.is_absolute_timeout()); + EXPECT_TRUE(t.is_relative_timeout()); + EXPECT_LE(absl::AbsDuration(absl::Now() + duration - + absl::TimeFromTimespec(t.MakeAbsTimespec())), + absl::Milliseconds(5)); + EXPECT_EQ(absl::DurationFromTimespec(t.MakeRelativeTimespec()), duration); + EXPECT_LE(absl::AbsDuration(absl::Now() + duration - + absl::FromUnixNanos(t.MakeAbsNanos())), + absl::Milliseconds(5)); + EXPECT_LE(absl::Milliseconds(t.InMillisecondsFromNow()) - duration, + absl::Milliseconds(5)); + } +} + +TEST(KernelTimeout, NegativeDurations) { + constexpr absl::Duration kDurationsToTest[] = { + -absl::ZeroDuration(), + -absl::Nanoseconds(1), + -absl::Microseconds(1), + -absl::Milliseconds(1), + -absl::Seconds(1), + -absl::Minutes(1), + -absl::Hours(1), + -absl::Hours(1000), + -absl::InfiniteDuration(), + }; + + for (auto duration : kDurationsToTest) { + // Negative durations should all be converted to zero durations or "now". + SCOPED_TRACE(duration); + KernelTimeout t(duration); + EXPECT_TRUE(t.has_timeout()); + EXPECT_FALSE(t.is_absolute_timeout()); + EXPECT_TRUE(t.is_relative_timeout()); + EXPECT_LE(absl::AbsDuration(absl::Now() - + absl::TimeFromTimespec(t.MakeAbsTimespec())), + absl::Milliseconds(5)); + EXPECT_EQ(absl::DurationFromTimespec(t.MakeRelativeTimespec()), + absl::ZeroDuration()); + EXPECT_LE( + absl::AbsDuration(absl::Now() - absl::FromUnixNanos(t.MakeAbsNanos())), + absl::Milliseconds(5)); + EXPECT_EQ(t.InMillisecondsFromNow(), KernelTimeout::DWord{0}); + } +} + +TEST(KernelTimeout, InfiniteDuration) { + KernelTimeout t(absl::InfiniteDuration()); + EXPECT_FALSE(t.has_timeout()); + // Callers are expected to check has_timeout() instead of using the methods + // below, but we do try to do something reasonable if they don't. We may not + // be able to round-trip back to absl::InfiniteDuration() or + // absl::InfiniteFuture(), but we should return a very large value. + EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), + absl::Now() + absl::Hours(100000)); + EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), + absl::Hours(100000)); + EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), + absl::Now() + absl::Hours(100000)); + EXPECT_EQ(t.InMillisecondsFromNow(), + std::numeric_limits<KernelTimeout::DWord>::max()); +} + +TEST(KernelTimeout, DurationMaxNanos) { + // Duration >= kMaxNanos should behave as no timeout. + KernelTimeout t(absl::Nanoseconds(std::numeric_limits<int64_t>::max())); + EXPECT_FALSE(t.has_timeout()); + // Callers are expected to check has_timeout() instead of using the methods + // below, but we do try to do something reasonable if they don't. We may not + // be able to round-trip back to absl::InfiniteDuration() or + // absl::InfiniteFuture(), but we should return a very large value. + EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), + absl::Now() + absl::Hours(100000)); + EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), + absl::Hours(100000)); + EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), + absl::Now() + absl::Hours(100000)); + EXPECT_EQ(t.InMillisecondsFromNow(), + std::numeric_limits<KernelTimeout::DWord>::max()); +} + +TEST(KernelTimeout, OverflowNanos) { + // Test what happens when KernelTimeout is constructed with an absl::Duration + // that would overflow now_nanos + duration. + int64_t now_nanos = absl::ToUnixNanos(absl::Now()); + int64_t limit = std::numeric_limits<int64_t>::max() - now_nanos; + absl::Duration duration = absl::Nanoseconds(limit) + absl::Seconds(1); + KernelTimeout t(duration); + EXPECT_TRUE(t.has_timeout()); + // Timeouts should still be far in the future. + EXPECT_GT(absl::TimeFromTimespec(t.MakeAbsTimespec()), + absl::Now() + absl::Hours(100000)); + EXPECT_GT(absl::DurationFromTimespec(t.MakeRelativeTimespec()), + absl::Hours(100000)); + EXPECT_GT(absl::FromUnixNanos(t.MakeAbsNanos()), + absl::Now() + absl::Hours(100000)); + EXPECT_LE(absl::Milliseconds(t.InMillisecondsFromNow()) - duration, + absl::Milliseconds(5)); +} + +} // namespace |