--
5ff0c4b38386ae80b25e9f8d0e1bac07fd7ce92c by Martijn Vels <mvels@google.com>:
Add CordzUpdateTracker class
PiperOrigin-RevId: 368469046
--
4de916b1ba4b5480b4dbe93d28c5eaa110449c66 by Derek Mauro <dmauro@google.com>:
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
b97a1ecda8/absl/types/span.h (L209-L248)
PiperOrigin-RevId: 368429085
--
bb6669016412bf5afffc02d0818a66dfe1c524cf by Martijn Vels <mvels@google.com>:
Reorganize internal cord code in CMakeLists.txt into cord_internal library
PiperOrigin-RevId: 368423765
--
d1d7fce066172d5fcfa0310c4e27631d895d7e50 by Derek Mauro <dmauro@google.com>:
Internal change
PiperOrigin-RevId: 368346725
GitOrigin-RevId: 5ff0c4b38386ae80b25e9f8d0e1bac07fd7ce92c
Change-Id: Ic4627eab4f0274e400a6d12cde3341fb538de075
pull/946/head
Abseil Team
4 years ago
committed by
Dino Radaković
parent
db1b7310d7
commit
46dfbfe31c
6 changed files with 310 additions and 17 deletions
@ -0,0 +1,96 @@ |
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// Copyright 2021 The Abseil Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef ABSL_STRINGS_INTERNAL_CORDZ_UPDATE_TRACKER_H_ |
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#define ABSL_STRINGS_INTERNAL_CORDZ_UPDATE_TRACKER_H_ |
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#include <atomic> |
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#include <cstdint> |
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#include "absl/base/config.h" |
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namespace absl { |
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ABSL_NAMESPACE_BEGIN |
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namespace cord_internal { |
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// CordzUpdateTracker tracks counters for Cord update methods.
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//
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// The purpose of CordzUpdateTracker is to track the number of calls to methods
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// updating Cord data for sampled cords. The class internally uses 'lossy'
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// atomic operations: Cord is thread-compatible, so there is no need to
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// synchronize updates. However, Cordz collection threads may call 'Value()' at
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// any point, so the class needs to provide thread safe access.
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//
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// This class is thread-safe. But as per above comments, all non-const methods
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// should be used single-threaded only: updates are thread-safe but lossy.
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class CordzUpdateTracker { |
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public: |
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// Tracked update methods.
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enum MethodIdentifier { |
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kAssignString, |
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kAssignCord, |
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kMoveAssignCord, |
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kAppendString, |
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kAppendCord, |
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kMoveAppendCord, |
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kPrependString, |
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kPrependCord, |
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kMovePrependCord, |
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kAppendExternalMemory, |
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kFlatten, |
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kGetAppendRegion, |
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kRemovePrefix, |
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kRemoveSuffic, |
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kSubCord, |
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// kNumMethods defines the number of entries: must be the last entry.
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kNumMethods, |
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}; |
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// Constructs a new instance. All counters are zero-initialized.
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constexpr CordzUpdateTracker() noexcept : values_{} {} |
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// Copy constructs a new instance.
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CordzUpdateTracker(const CordzUpdateTracker& rhs) noexcept { *this = rhs; } |
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// Assigns the provided value to this instance.
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CordzUpdateTracker& operator=(const CordzUpdateTracker& rhs) noexcept { |
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for (int i = 0; i < kNumMethods; ++i) { |
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values_[i].store(rhs.values_[i].load(std::memory_order_relaxed), |
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std::memory_order_relaxed); |
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} |
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return *this; |
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} |
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// Returns the value for the specified method.
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int64_t Value(MethodIdentifier method) const { |
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return values_[method].load(std::memory_order_relaxed); |
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} |
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// Increases the value for the specified method by `n`
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void LossyAdd(MethodIdentifier method, int64_t n = 1) { |
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auto& value = values_[method]; |
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value.store(value.load(std::memory_order_relaxed) + n, |
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std::memory_order_relaxed); |
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} |
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private: |
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std::atomic<int64_t> values_[kNumMethods]; |
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}; |
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} // namespace cord_internal
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ABSL_NAMESPACE_END |
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} // namespace absl
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#endif // ABSL_STRINGS_INTERNAL_CORDZ_UPDATE_TRACKER_H_
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@ -0,0 +1,130 @@ |
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// Copyright 2021 The Abseil Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "absl/strings/internal/cordz_update_tracker.h" |
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#include <array> |
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#include <thread> // NOLINT |
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#include "gmock/gmock.h" |
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#include "gtest/gtest.h" |
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#include "absl/base/attributes.h" |
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#include "absl/base/config.h" |
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#include "absl/synchronization/notification.h" |
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namespace absl { |
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ABSL_NAMESPACE_BEGIN |
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namespace cord_internal { |
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namespace { |
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using ::testing::AnyOf; |
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using ::testing::Eq; |
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using Method = CordzUpdateTracker::MethodIdentifier; |
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using Methods = std::array<Method, Method::kNumMethods>; |
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// Returns an array of all methods defined in `MethodIdentifier`
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Methods AllMethods() { |
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return Methods{Method::kAssignString, Method::kAssignCord, |
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Method::kMoveAssignCord, Method::kAppendString, |
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Method::kAppendCord, Method::kMoveAppendCord, |
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Method::kPrependString, Method::kPrependCord, |
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Method::kMovePrependCord, Method::kAppendExternalMemory, |
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Method::kFlatten, Method::kGetAppendRegion, |
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Method::kRemovePrefix, Method::kRemoveSuffic, |
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Method::kSubCord}; |
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} |
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TEST(CordzUpdateTracker, IsConstExprAndInitializesToZero) { |
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constexpr CordzUpdateTracker tracker; |
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for (Method method : AllMethods()) { |
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ASSERT_THAT(tracker.Value(method), Eq(0)); |
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} |
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} |
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TEST(CordzUpdateTracker, LossyAdd) { |
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int64_t n = 1; |
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CordzUpdateTracker tracker; |
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for (Method method : AllMethods()) { |
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tracker.LossyAdd(method, n); |
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EXPECT_THAT(tracker.Value(method), Eq(n)); |
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n += 2; |
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} |
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} |
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TEST(CordzUpdateTracker, CopyConstructor) { |
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int64_t n = 1; |
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CordzUpdateTracker src; |
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for (Method method : AllMethods()) { |
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src.LossyAdd(method, n); |
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n += 2; |
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} |
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n = 1; |
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CordzUpdateTracker tracker(src); |
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for (Method method : AllMethods()) { |
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EXPECT_THAT(tracker.Value(method), Eq(n)); |
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n += 2; |
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} |
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} |
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TEST(CordzUpdateTracker, OperatorAssign) { |
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int64_t n = 1; |
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CordzUpdateTracker src; |
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CordzUpdateTracker tracker; |
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for (Method method : AllMethods()) { |
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src.LossyAdd(method, n); |
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n += 2; |
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} |
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n = 1; |
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tracker = src; |
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for (Method method : AllMethods()) { |
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EXPECT_THAT(tracker.Value(method), Eq(n)); |
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n += 2; |
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} |
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} |
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TEST(CordzUpdateTracker, ThreadSanitizedValueCheck) { |
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absl::Notification done; |
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CordzUpdateTracker tracker; |
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std::thread reader([&done, &tracker] { |
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while (!done.HasBeenNotified()) { |
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int n = 1; |
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for (Method method : AllMethods()) { |
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EXPECT_THAT(tracker.Value(method), AnyOf(Eq(n), Eq(0))); |
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n += 2; |
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} |
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} |
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int n = 1; |
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for (Method method : AllMethods()) { |
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EXPECT_THAT(tracker.Value(method), Eq(n)); |
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n += 2; |
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} |
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}); |
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int64_t n = 1; |
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for (Method method : AllMethods()) { |
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tracker.LossyAdd(method, n); |
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n += 2; |
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} |
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done.Notify(); |
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reader.join(); |
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} |
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} // namespace
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} // namespace cord_internal
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ABSL_NAMESPACE_END |
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} // namespace absl
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