182 lines
6.7 KiB
C++
182 lines
6.7 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 <cstdlib>
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#include <thread> // NOLINT(build/c++11), Abseil test
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#include <type_traits>
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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/internal/raw_logging.h"
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#include "absl/base/thread_annotations.h"
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#include "absl/synchronization/mutex.h"
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#include "absl/synchronization/notification.h"
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namespace {
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// A two-threaded test which checks that Mutex, CondVar, and Notification have
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// correct basic functionality. The intent is to establish that they
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// function correctly in various phases of construction and destruction.
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//
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// Thread one acquires a lock on 'mutex', wakes thread two via 'notification',
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// then waits for 'state' to be set, as signalled by 'condvar'.
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//
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// Thread two waits on 'notification', then sets 'state' inside the 'mutex',
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// signalling the change via 'condvar'.
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//
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// These tests use ABSL_RAW_CHECK to validate invariants, rather than EXPECT or
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// ASSERT from gUnit, because we need to invoke them during global destructors,
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// when gUnit teardown would have already begun.
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void ThreadOne(absl::Mutex* mutex, absl::CondVar* condvar,
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absl::Notification* notification, bool* state) {
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// Test that the notification is in a valid initial state.
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ABSL_RAW_CHECK(!notification->HasBeenNotified(), "invalid Notification");
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ABSL_RAW_CHECK(*state == false, "*state not initialized");
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{
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absl::MutexLock lock(mutex);
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notification->Notify();
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ABSL_RAW_CHECK(notification->HasBeenNotified(), "invalid Notification");
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while (*state == false) {
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condvar->Wait(mutex);
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}
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}
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}
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void ThreadTwo(absl::Mutex* mutex, absl::CondVar* condvar,
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absl::Notification* notification, bool* state) {
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ABSL_RAW_CHECK(*state == false, "*state not initialized");
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// Wake thread one
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notification->WaitForNotification();
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ABSL_RAW_CHECK(notification->HasBeenNotified(), "invalid Notification");
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{
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absl::MutexLock lock(mutex);
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*state = true;
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condvar->Signal();
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}
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}
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// Launch thread 1 and thread 2, and block on their completion.
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// If any of 'mutex', 'condvar', or 'notification' is nullptr, use a locally
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// constructed instance instead.
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void RunTests(absl::Mutex* mutex, absl::CondVar* condvar) {
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absl::Mutex default_mutex;
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absl::CondVar default_condvar;
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absl::Notification notification;
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if (!mutex) {
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mutex = &default_mutex;
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}
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if (!condvar) {
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condvar = &default_condvar;
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}
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bool state = false;
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std::thread thread_one(ThreadOne, mutex, condvar, ¬ification, &state);
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std::thread thread_two(ThreadTwo, mutex, condvar, ¬ification, &state);
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thread_one.join();
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thread_two.join();
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}
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void TestLocals() {
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absl::Mutex mutex;
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absl::CondVar condvar;
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RunTests(&mutex, &condvar);
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}
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// Normal kConstInit usage
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ABSL_CONST_INIT absl::Mutex const_init_mutex(absl::kConstInit);
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void TestConstInitGlobal() { RunTests(&const_init_mutex, nullptr); }
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// Global variables during start and termination
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//
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// In a translation unit, static storage duration variables are initialized in
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// the order of their definitions, and destroyed in the reverse order of their
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// definitions. We can use this to arrange for tests to be run on these objects
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// before they are created, and after they are destroyed.
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using Function = void (*)();
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class OnConstruction {
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public:
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explicit OnConstruction(Function fn) { fn(); }
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};
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class OnDestruction {
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public:
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explicit OnDestruction(Function fn) : fn_(fn) {}
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~OnDestruction() { fn_(); }
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private:
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Function fn_;
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};
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// These tests require that the compiler correctly supports C++11 constant
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// initialization... but MSVC has a known regression since v19.10:
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// https://developercommunity.visualstudio.com/content/problem/336946/class-with-constexpr-constructor-not-using-static.html
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// TODO(epastor): Limit the affected range once MSVC fixes this bug.
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#if defined(__clang__) || !(defined(_MSC_VER) && _MSC_VER > 1900)
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// kConstInit
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// Test early usage. (Declaration comes first; definitions must appear after
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// the test runner.)
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extern absl::Mutex early_const_init_mutex;
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// (Normally I'd write this +[], to make the cast-to-function-pointer explicit,
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// but in some MSVC setups we support, lambdas provide conversion operators to
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// different flavors of function pointers, making this trick ambiguous.)
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OnConstruction test_early_const_init([] {
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RunTests(&early_const_init_mutex, nullptr);
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});
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// This definition appears before test_early_const_init, but it should be
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// initialized first (due to constant initialization). Test that the object
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// actually works when constructed this way.
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ABSL_CONST_INIT absl::Mutex early_const_init_mutex(absl::kConstInit);
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// Furthermore, test that the const-init c'tor doesn't stomp over the state of
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// a Mutex. Really, this is a test that the platform under test correctly
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// supports C++11 constant initialization. (The constant-initialization
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// constructors of globals "happen at link time"; memory is pre-initialized,
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// before the constructors of either grab_lock or check_still_locked are run.)
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extern absl::Mutex const_init_sanity_mutex;
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OnConstruction grab_lock([]() ABSL_NO_THREAD_SAFETY_ANALYSIS {
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const_init_sanity_mutex.Lock();
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});
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ABSL_CONST_INIT absl::Mutex const_init_sanity_mutex(absl::kConstInit);
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OnConstruction check_still_locked([]() ABSL_NO_THREAD_SAFETY_ANALYSIS {
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const_init_sanity_mutex.AssertHeld();
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const_init_sanity_mutex.Unlock();
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});
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#endif // defined(__clang__) || !(defined(_MSC_VER) && _MSC_VER > 1900)
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// Test shutdown usage. (Declarations come first; definitions must appear after
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// the test runner.)
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extern absl::Mutex late_const_init_mutex;
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// OnDestruction is being used here as a global variable, even though it has a
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// non-trivial destructor. This is against the style guide. We're violating
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// that rule here to check that the exception we allow for kConstInit is safe.
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// NOLINTNEXTLINE
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OnDestruction test_late_const_init([] {
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RunTests(&late_const_init_mutex, nullptr);
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});
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ABSL_CONST_INIT absl::Mutex late_const_init_mutex(absl::kConstInit);
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} // namespace
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int main() {
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TestLocals();
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TestConstInitGlobal();
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// Explicitly call exit(0) here, to make it clear that we intend for the
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// above global object destructors to run.
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std::exit(0);
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}
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