1e39f8626a
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b842b7fd9b1289be31f0b7ee8e62e48e550747cf by Greg Falcon <gfalcon@google.com>:
Change the Cord str_format formatter to use iteration instead of CordReader.
When Cord is publicly released, CordReader is not going with it.
PiperOrigin-RevId: 284780736
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28e76c08ea7185a7ff9f4e0e02ae565fbbf7980f by Greg Falcon <gfalcon@google.com>:
Implementation detail change.
Introduce ABSL_NAMESPACE_BEGIN and _END annotation macros which indicate the beginning and end of a `namespace absl` scope. Currently these do nothing, but they will be used to inject an inline namespace for LTS builds (to avoid symbol collisions against other Abseil versions).
These macros should not be used by end users, because end users should never write `namespace absl {` in their own code.
This CL applies these annotations to all code under //absl/base/. The rest of Abseil will be annotated in this way in follow-up CLs.
PiperOrigin-RevId: 284776410
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e1711dc6d696dcca50d4e7d4b4d8f3076575b7ec by Abseil Team <absl-team@google.com>:
--help changed to report long flags.
PiperOrigin-RevId: 284757720
--
78f66a68f428bbbd19d8d60e1125f43ba765fd35 by Tom Manshreck <shreck@google.com>:
Update comment on + or - in SimpleAToi()
PiperOrigin-RevId: 284231843
GitOrigin-RevId: b842b7fd9b1289be31f0b7ee8e62e48e550747cf
Change-Id: I3046b31391bd11c8bc4abab7785a863c377cd757
107 lines
3.1 KiB
C++
107 lines
3.1 KiB
C++
// Copyright 2017 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/base/call_once.h"
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#include <thread>
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#include <vector>
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#include "gtest/gtest.h"
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#include "absl/base/attributes.h"
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#include "absl/base/const_init.h"
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#include "absl/base/thread_annotations.h"
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#include "absl/synchronization/mutex.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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namespace {
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absl::once_flag once;
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ABSL_CONST_INIT Mutex counters_mu(absl::kConstInit);
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int running_thread_count ABSL_GUARDED_BY(counters_mu) = 0;
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int call_once_invoke_count ABSL_GUARDED_BY(counters_mu) = 0;
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int call_once_finished_count ABSL_GUARDED_BY(counters_mu) = 0;
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int call_once_return_count ABSL_GUARDED_BY(counters_mu) = 0;
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bool done_blocking ABSL_GUARDED_BY(counters_mu) = false;
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// Function to be called from absl::call_once. Waits for a notification.
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void WaitAndIncrement() {
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counters_mu.Lock();
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++call_once_invoke_count;
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counters_mu.Unlock();
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counters_mu.LockWhen(Condition(&done_blocking));
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++call_once_finished_count;
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counters_mu.Unlock();
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}
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void ThreadBody() {
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counters_mu.Lock();
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++running_thread_count;
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counters_mu.Unlock();
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absl::call_once(once, WaitAndIncrement);
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counters_mu.Lock();
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++call_once_return_count;
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counters_mu.Unlock();
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}
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// Returns true if all threads are set up for the test.
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bool ThreadsAreSetup(void*) ABSL_EXCLUSIVE_LOCKS_REQUIRED(counters_mu) {
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// All ten threads must be running, and WaitAndIncrement should be blocked.
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return running_thread_count == 10 && call_once_invoke_count == 1;
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}
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TEST(CallOnceTest, ExecutionCount) {
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std::vector<std::thread> threads;
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// Start 10 threads all calling call_once on the same once_flag.
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for (int i = 0; i < 10; ++i) {
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threads.emplace_back(ThreadBody);
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}
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// Wait until all ten threads have started, and WaitAndIncrement has been
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// invoked.
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counters_mu.LockWhen(Condition(ThreadsAreSetup, nullptr));
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// WaitAndIncrement should have been invoked by exactly one call_once()
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// instance. That thread should be blocking on a notification, and all other
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// call_once instances should be blocking as well.
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EXPECT_EQ(call_once_invoke_count, 1);
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EXPECT_EQ(call_once_finished_count, 0);
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EXPECT_EQ(call_once_return_count, 0);
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// Allow WaitAndIncrement to finish executing. Once it does, the other
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// call_once waiters will be unblocked.
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done_blocking = true;
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counters_mu.Unlock();
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for (std::thread& thread : threads) {
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thread.join();
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}
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counters_mu.Lock();
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EXPECT_EQ(call_once_invoke_count, 1);
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EXPECT_EQ(call_once_finished_count, 1);
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EXPECT_EQ(call_once_return_count, 10);
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counters_mu.Unlock();
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}
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} // namespace
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ABSL_NAMESPACE_END
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} // namespace absl
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