From 46dfbfe31ca1dd414e4c33cbcbcd7199bb4efde3 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Wed, 14 Apr 2021 11:19:20 -0700 Subject: Export of internal Abseil changes -- 5ff0c4b38386ae80b25e9f8d0e1bac07fd7ce92c by Martijn Vels : Add CordzUpdateTracker class PiperOrigin-RevId: 368469046 -- 4de916b1ba4b5480b4dbe93d28c5eaa110449c66 by Derek Mauro : Adds `ABSL_ATTRIBUTE_LIFETIME_BOUND` to `absl::Span`s initializer_list constructor. Compilers that support this attribute will emit a warning if the parameter does not have sufficient lifetime. For more information, see https://github.com/abseil/abseil-cpp/blob/b97a1ecda869ca8754d467a56c50275cebfeb328/absl/types/span.h#L209-L248 PiperOrigin-RevId: 368429085 -- bb6669016412bf5afffc02d0818a66dfe1c524cf by Martijn Vels : Reorganize internal cord code in CMakeLists.txt into cord_internal library PiperOrigin-RevId: 368423765 -- d1d7fce066172d5fcfa0310c4e27631d895d7e50 by Derek Mauro : Internal change PiperOrigin-RevId: 368346725 GitOrigin-RevId: 5ff0c4b38386ae80b25e9f8d0e1bac07fd7ce92c Change-Id: Ic4627eab4f0274e400a6d12cde3341fb538de075 --- absl/strings/BUILD.bazel | 21 ++++ absl/strings/CMakeLists.txt | 75 +++++++++--- absl/strings/internal/cordz_update_tracker.h | 96 +++++++++++++++ absl/strings/internal/cordz_update_tracker_test.cc | 130 +++++++++++++++++++++ absl/types/span.h | 4 +- 5 files changed, 309 insertions(+), 17 deletions(-) create mode 100644 absl/strings/internal/cordz_update_tracker.h create mode 100644 absl/strings/internal/cordz_update_tracker_test.cc (limited to 'absl') diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel index 123b5efb..11385163 100644 --- a/absl/strings/BUILD.bazel +++ b/absl/strings/BUILD.bazel @@ -296,6 +296,26 @@ cc_library( ], ) +cc_library( + name = "cordz_update_tracker", + hdrs = ["internal/cordz_update_tracker.h"], + copts = ABSL_DEFAULT_COPTS, + visibility = ["//visibility:private"], + deps = ["//absl/base:config"], +) + +cc_test( + name = "cordz_update_tracker_test", + srcs = ["internal/cordz_update_tracker_test.cc"], + deps = [ + ":cordz_update_tracker", + "//absl/base:config", + "//absl/base:core_headers", + "//absl/synchronization", + "@com_google_googletest//:gtest_main", + ], +) + cc_library( name = "cord", srcs = [ @@ -307,6 +327,7 @@ cc_library( copts = ABSL_DEFAULT_COPTS, deps = [ ":cord_internal", + ":cordz_update_tracker", ":internal", ":str_format", ":strings", diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt index 3b7ae639..0d93d5ff 100644 --- a/absl/strings/CMakeLists.txt +++ b/absl/strings/CMakeLists.txt @@ -550,6 +550,59 @@ absl_cc_test( gmock_main ) +absl_cc_library( + NAME + cord_internal + HDRS + "internal/cord_internal.h" + "internal/cord_rep_flat.h" + "internal/cord_rep_ring.h" + "internal/cord_rep_ring_reader.h" + SRCS + "internal/cord_internal.cc" + "internal/cord_rep_ring.cc" + COPTS + ${ABSL_TEST_COPTS} + DEPS + absl::base_internal + absl::compressed_tuple + absl::config + absl::core_headers + absl::endian + absl::inlined_vector + absl::layout + absl::raw_logging_internal + absl::strings + absl::throw_delegate + absl::type_traits +) + +absl_cc_library( + NAME + cordz_update_tracker + HDRS + "internal/cordz_update_tracker.h" + COPTS + ${ABSL_TEST_COPTS} + DEPS + absl::config +) + +absl_cc_test( + NAME + cordz_update_tracker_test + SRCS + "internal/cordz_update_tracker_test.cc" + COPTS + ${ABSL_TEST_COPTS} + DEPS + absl::config + absl::cordz_update_tracker + absl::core_headers + absl::synchronization + gmock_main +) + absl_cc_library( NAME cord @@ -557,19 +610,13 @@ absl_cc_library( "cord.h" SRCS "cord.cc" - "internal/cord_internal.cc" - "internal/cord_internal.h" - "internal/cord_rep_ring.h" - "internal/cord_rep_ring.cc" - "internal/cord_rep_ring_reader.h" - "internal/cord_rep_flat.h" COPTS ${ABSL_DEFAULT_COPTS} DEPS absl::base - absl::base_internal - absl::compressed_tuple absl::config + absl::cord_internal + absl::cordz_update_tracker absl::core_headers absl::endian absl::fixed_array @@ -578,8 +625,6 @@ absl_cc_library( absl::optional absl::raw_logging_internal absl::strings - absl::strings_internal - absl::throw_delegate absl::type_traits PUBLIC ) @@ -624,12 +669,12 @@ absl_cc_test( COPTS ${ABSL_TEST_COPTS} DEPS - absl::config - absl::cord - absl::strings absl::base + absl::config + absl::cord_internal absl::core_headers absl::raw_logging_internal + absl::strings gmock_main ) @@ -641,9 +686,9 @@ absl_cc_test( COPTS ${ABSL_TEST_COPTS} DEPS - absl::cord - absl::strings absl::base + absl::cord_internal absl::core_headers + absl::strings gmock_main ) diff --git a/absl/strings/internal/cordz_update_tracker.h b/absl/strings/internal/cordz_update_tracker.h new file mode 100644 index 00000000..3c617e93 --- /dev/null +++ b/absl/strings/internal/cordz_update_tracker.h @@ -0,0 +1,96 @@ +// Copyright 2021 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. + +#ifndef ABSL_STRINGS_INTERNAL_CORDZ_UPDATE_TRACKER_H_ +#define ABSL_STRINGS_INTERNAL_CORDZ_UPDATE_TRACKER_H_ + +#include +#include + +#include "absl/base/config.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace cord_internal { + +// CordzUpdateTracker tracks counters for Cord update methods. +// +// The purpose of CordzUpdateTracker is to track the number of calls to methods +// updating Cord data for sampled cords. The class internally uses 'lossy' +// atomic operations: Cord is thread-compatible, so there is no need to +// synchronize updates. However, Cordz collection threads may call 'Value()' at +// any point, so the class needs to provide thread safe access. +// +// This class is thread-safe. But as per above comments, all non-const methods +// should be used single-threaded only: updates are thread-safe but lossy. +class CordzUpdateTracker { + public: + // Tracked update methods. + enum MethodIdentifier { + kAssignString, + kAssignCord, + kMoveAssignCord, + kAppendString, + kAppendCord, + kMoveAppendCord, + kPrependString, + kPrependCord, + kMovePrependCord, + kAppendExternalMemory, + kFlatten, + kGetAppendRegion, + kRemovePrefix, + kRemoveSuffic, + kSubCord, + + // kNumMethods defines the number of entries: must be the last entry. + kNumMethods, + }; + + // Constructs a new instance. All counters are zero-initialized. + constexpr CordzUpdateTracker() noexcept : values_{} {} + + // Copy constructs a new instance. + CordzUpdateTracker(const CordzUpdateTracker& rhs) noexcept { *this = rhs; } + + // Assigns the provided value to this instance. + CordzUpdateTracker& operator=(const CordzUpdateTracker& rhs) noexcept { + for (int i = 0; i < kNumMethods; ++i) { + values_[i].store(rhs.values_[i].load(std::memory_order_relaxed), + std::memory_order_relaxed); + } + return *this; + } + + // Returns the value for the specified method. + int64_t Value(MethodIdentifier method) const { + return values_[method].load(std::memory_order_relaxed); + } + + // Increases the value for the specified method by `n` + void LossyAdd(MethodIdentifier method, int64_t n = 1) { + auto& value = values_[method]; + value.store(value.load(std::memory_order_relaxed) + n, + std::memory_order_relaxed); + } + + private: + std::atomic values_[kNumMethods]; +}; + +} // namespace cord_internal +ABSL_NAMESPACE_END +} // namespace absl + +#endif // ABSL_STRINGS_INTERNAL_CORDZ_UPDATE_TRACKER_H_ diff --git a/absl/strings/internal/cordz_update_tracker_test.cc b/absl/strings/internal/cordz_update_tracker_test.cc new file mode 100644 index 00000000..45782046 --- /dev/null +++ b/absl/strings/internal/cordz_update_tracker_test.cc @@ -0,0 +1,130 @@ +// Copyright 2021 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/strings/internal/cordz_update_tracker.h" + +#include +#include // NOLINT + +#include "gmock/gmock.h" +#include "gtest/gtest.h" +#include "absl/base/attributes.h" +#include "absl/base/config.h" +#include "absl/synchronization/notification.h" + +namespace absl { +ABSL_NAMESPACE_BEGIN +namespace cord_internal { +namespace { + +using ::testing::AnyOf; +using ::testing::Eq; + +using Method = CordzUpdateTracker::MethodIdentifier; +using Methods = std::array; + +// Returns an array of all methods defined in `MethodIdentifier` +Methods AllMethods() { + return Methods{Method::kAssignString, Method::kAssignCord, + Method::kMoveAssignCord, Method::kAppendString, + Method::kAppendCord, Method::kMoveAppendCord, + Method::kPrependString, Method::kPrependCord, + Method::kMovePrependCord, Method::kAppendExternalMemory, + Method::kFlatten, Method::kGetAppendRegion, + Method::kRemovePrefix, Method::kRemoveSuffic, + Method::kSubCord}; +} + +TEST(CordzUpdateTracker, IsConstExprAndInitializesToZero) { + constexpr CordzUpdateTracker tracker; + for (Method method : AllMethods()) { + ASSERT_THAT(tracker.Value(method), Eq(0)); + } +} + +TEST(CordzUpdateTracker, LossyAdd) { + int64_t n = 1; + CordzUpdateTracker tracker; + for (Method method : AllMethods()) { + tracker.LossyAdd(method, n); + EXPECT_THAT(tracker.Value(method), Eq(n)); + n += 2; + } +} + +TEST(CordzUpdateTracker, CopyConstructor) { + int64_t n = 1; + CordzUpdateTracker src; + for (Method method : AllMethods()) { + src.LossyAdd(method, n); + n += 2; + } + + n = 1; + CordzUpdateTracker tracker(src); + for (Method method : AllMethods()) { + EXPECT_THAT(tracker.Value(method), Eq(n)); + n += 2; + } +} + +TEST(CordzUpdateTracker, OperatorAssign) { + int64_t n = 1; + CordzUpdateTracker src; + CordzUpdateTracker tracker; + for (Method method : AllMethods()) { + src.LossyAdd(method, n); + n += 2; + } + + n = 1; + tracker = src; + for (Method method : AllMethods()) { + EXPECT_THAT(tracker.Value(method), Eq(n)); + n += 2; + } +} + +TEST(CordzUpdateTracker, ThreadSanitizedValueCheck) { + absl::Notification done; + CordzUpdateTracker tracker; + + std::thread reader([&done, &tracker] { + while (!done.HasBeenNotified()) { + int n = 1; + for (Method method : AllMethods()) { + EXPECT_THAT(tracker.Value(method), AnyOf(Eq(n), Eq(0))); + n += 2; + } + } + int n = 1; + for (Method method : AllMethods()) { + EXPECT_THAT(tracker.Value(method), Eq(n)); + n += 2; + } + }); + + int64_t n = 1; + for (Method method : AllMethods()) { + tracker.LossyAdd(method, n); + n += 2; + } + done.Notify(); + reader.join(); +} + +} // namespace +} // namespace cord_internal +ABSL_NAMESPACE_END +} // namespace absl diff --git a/absl/types/span.h b/absl/types/span.h index 95fe7926..41db3420 100644 --- a/absl/types/span.h +++ b/absl/types/span.h @@ -243,8 +243,8 @@ class Span { // template > - Span( - std::initializer_list v) noexcept // NOLINT(runtime/explicit) + Span(std::initializer_list v + ABSL_ATTRIBUTE_LIFETIME_BOUND) noexcept // NOLINT(runtime/explicit) : Span(v.begin(), v.size()) {} // Accessors -- cgit v1.2.3