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Diffstat (limited to 'third_party/abseil_cpp/absl/synchronization/internal/waiter.cc')
-rw-r--r--third_party/abseil_cpp/absl/synchronization/internal/waiter.cc428
1 files changed, 0 insertions, 428 deletions
diff --git a/third_party/abseil_cpp/absl/synchronization/internal/waiter.cc b/third_party/abseil_cpp/absl/synchronization/internal/waiter.cc
deleted file mode 100644
index 2123be60f54f..000000000000
--- a/third_party/abseil_cpp/absl/synchronization/internal/waiter.cc
+++ /dev/null
@@ -1,428 +0,0 @@
-// Copyright 2017 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/waiter.h"
-
-#include "absl/base/config.h"
-
-#ifdef _WIN32
-#include <windows.h>
-#else
-#include <pthread.h>
-#include <sys/time.h>
-#include <unistd.h>
-#endif
-
-#ifdef __linux__
-#include <linux/futex.h>
-#include <sys/syscall.h>
-#endif
-
-#ifdef ABSL_HAVE_SEMAPHORE_H
-#include <semaphore.h>
-#endif
-
-#include <errno.h>
-#include <stdio.h>
-#include <time.h>
-
-#include <atomic>
-#include <cassert>
-#include <cstdint>
-#include <new>
-#include <type_traits>
-
-#include "absl/base/internal/raw_logging.h"
-#include "absl/base/internal/thread_identity.h"
-#include "absl/base/optimization.h"
-#include "absl/synchronization/internal/kernel_timeout.h"
-
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace synchronization_internal {
-
-static void MaybeBecomeIdle() {
-  base_internal::ThreadIdentity *identity =
-      base_internal::CurrentThreadIdentityIfPresent();
-  assert(identity != nullptr);
-  const bool is_idle = identity->is_idle.load(std::memory_order_relaxed);
-  const int ticker = identity->ticker.load(std::memory_order_relaxed);
-  const int wait_start = identity->wait_start.load(std::memory_order_relaxed);
-  if (!is_idle && ticker - wait_start > Waiter::kIdlePeriods) {
-    identity->is_idle.store(true, std::memory_order_relaxed);
-  }
-}
-
-#if ABSL_WAITER_MODE == ABSL_WAITER_MODE_FUTEX
-
-Waiter::Waiter() {
-  futex_.store(0, std::memory_order_relaxed);
-}
-
-Waiter::~Waiter() = default;
-
-bool Waiter::Wait(KernelTimeout t) {
-  // Loop until we can atomically decrement futex from a positive
-  // value, waiting on a futex while we believe it is zero.
-  // Note that, since the thread ticker is just reset, we don't need to check
-  // whether the thread is idle on the very first pass of the loop.
-  bool first_pass = true;
-  while (true) {
-    int32_t x = futex_.load(std::memory_order_relaxed);
-    while (x != 0) {
-      if (!futex_.compare_exchange_weak(x, x - 1,
-                                        std::memory_order_acquire,
-                                        std::memory_order_relaxed)) {
-        continue;  // Raced with someone, retry.
-      }
-      return true;  // Consumed a wakeup, we are done.
-    }
-
-
-    if (!first_pass) MaybeBecomeIdle();
-    const int err = Futex::WaitUntil(&futex_, 0, t);
-    if (err != 0) {
-      if (err == -EINTR || err == -EWOULDBLOCK) {
-        // Do nothing, the loop will retry.
-      } else if (err == -ETIMEDOUT) {
-        return false;
-      } else {
-        ABSL_RAW_LOG(FATAL, "Futex operation failed with error %d\n", err);
-      }
-    }
-    first_pass = false;
-  }
-}
-
-void Waiter::Post() {
-  if (futex_.fetch_add(1, std::memory_order_release) == 0) {
-    // We incremented from 0, need to wake a potential waiter.
-    Poke();
-  }
-}
-
-void Waiter::Poke() {
-  // Wake one thread waiting on the futex.
-  const int err = Futex::Wake(&futex_, 1);
-  if (ABSL_PREDICT_FALSE(err < 0)) {
-    ABSL_RAW_LOG(FATAL, "Futex operation failed with error %d\n", err);
-  }
-}
-
-#elif ABSL_WAITER_MODE == ABSL_WAITER_MODE_CONDVAR
-
-class PthreadMutexHolder {
- public:
-  explicit PthreadMutexHolder(pthread_mutex_t *mu) : mu_(mu) {
-    const int err = pthread_mutex_lock(mu_);
-    if (err != 0) {
-      ABSL_RAW_LOG(FATAL, "pthread_mutex_lock failed: %d", err);
-    }
-  }
-
-  PthreadMutexHolder(const PthreadMutexHolder &rhs) = delete;
-  PthreadMutexHolder &operator=(const PthreadMutexHolder &rhs) = delete;
-
-  ~PthreadMutexHolder() {
-    const int err = pthread_mutex_unlock(mu_);
-    if (err != 0) {
-      ABSL_RAW_LOG(FATAL, "pthread_mutex_unlock failed: %d", err);
-    }
-  }
-
- private:
-  pthread_mutex_t *mu_;
-};
-
-Waiter::Waiter() {
-  const int err = pthread_mutex_init(&mu_, 0);
-  if (err != 0) {
-    ABSL_RAW_LOG(FATAL, "pthread_mutex_init failed: %d", err);
-  }
-
-  const int err2 = pthread_cond_init(&cv_, 0);
-  if (err2 != 0) {
-    ABSL_RAW_LOG(FATAL, "pthread_cond_init failed: %d", err2);
-  }
-
-  waiter_count_ = 0;
-  wakeup_count_ = 0;
-}
-
-Waiter::~Waiter() {
-  const int err = pthread_mutex_destroy(&mu_);
-  if (err != 0) {
-    ABSL_RAW_LOG(FATAL, "pthread_mutex_destroy failed: %d", err);
-  }
-
-  const int err2 = pthread_cond_destroy(&cv_);
-  if (err2 != 0) {
-    ABSL_RAW_LOG(FATAL, "pthread_cond_destroy failed: %d", err2);
-  }
-}
-
-bool Waiter::Wait(KernelTimeout t) {
-  struct timespec abs_timeout;
-  if (t.has_timeout()) {
-    abs_timeout = t.MakeAbsTimespec();
-  }
-
-  PthreadMutexHolder h(&mu_);
-  ++waiter_count_;
-  // Loop until we find a wakeup to consume or timeout.
-  // Note that, since the thread ticker is just reset, we don't need to check
-  // whether the thread is idle on the very first pass of the loop.
-  bool first_pass = true;
-  while (wakeup_count_ == 0) {
-    if (!first_pass) MaybeBecomeIdle();
-    // No wakeups available, time to wait.
-    if (!t.has_timeout()) {
-      const int err = pthread_cond_wait(&cv_, &mu_);
-      if (err != 0) {
-        ABSL_RAW_LOG(FATAL, "pthread_cond_wait failed: %d", err);
-      }
-    } else {
-      const int err = pthread_cond_timedwait(&cv_, &mu_, &abs_timeout);
-      if (err == ETIMEDOUT) {
-        --waiter_count_;
-        return false;
-      }
-      if (err != 0) {
-        ABSL_RAW_LOG(FATAL, "pthread_cond_timedwait failed: %d", err);
-      }
-    }
-    first_pass = false;
-  }
-  // Consume a wakeup and we're done.
-  --wakeup_count_;
-  --waiter_count_;
-  return true;
-}
-
-void Waiter::Post() {
-  PthreadMutexHolder h(&mu_);
-  ++wakeup_count_;
-  InternalCondVarPoke();
-}
-
-void Waiter::Poke() {
-  PthreadMutexHolder h(&mu_);
-  InternalCondVarPoke();
-}
-
-void Waiter::InternalCondVarPoke() {
-  if (waiter_count_ != 0) {
-    const int err = pthread_cond_signal(&cv_);
-    if (ABSL_PREDICT_FALSE(err != 0)) {
-      ABSL_RAW_LOG(FATAL, "pthread_cond_signal failed: %d", err);
-    }
-  }
-}
-
-#elif ABSL_WAITER_MODE == ABSL_WAITER_MODE_SEM
-
-Waiter::Waiter() {
-  if (sem_init(&sem_, 0, 0) != 0) {
-    ABSL_RAW_LOG(FATAL, "sem_init failed with errno %d\n", errno);
-  }
-  wakeups_.store(0, std::memory_order_relaxed);
-}
-
-Waiter::~Waiter() {
-  if (sem_destroy(&sem_) != 0) {
-    ABSL_RAW_LOG(FATAL, "sem_destroy failed with errno %d\n", errno);
-  }
-}
-
-bool Waiter::Wait(KernelTimeout t) {
-  struct timespec abs_timeout;
-  if (t.has_timeout()) {
-    abs_timeout = t.MakeAbsTimespec();
-  }
-
-  // Loop until we timeout or consume a wakeup.
-  // Note that, since the thread ticker is just reset, we don't need to check
-  // whether the thread is idle on the very first pass of the loop.
-  bool first_pass = true;
-  while (true) {
-    int x = wakeups_.load(std::memory_order_relaxed);
-    while (x != 0) {
-      if (!wakeups_.compare_exchange_weak(x, x - 1,
-                                          std::memory_order_acquire,
-                                          std::memory_order_relaxed)) {
-        continue;  // Raced with someone, retry.
-      }
-      // Successfully consumed a wakeup, we're done.
-      return true;
-    }
-
-    if (!first_pass) MaybeBecomeIdle();
-    // Nothing to consume, wait (looping on EINTR).
-    while (true) {
-      if (!t.has_timeout()) {
-        if (sem_wait(&sem_) == 0) break;
-        if (errno == EINTR) continue;
-        ABSL_RAW_LOG(FATAL, "sem_wait failed: %d", errno);
-      } else {
-        if (sem_timedwait(&sem_, &abs_timeout) == 0) break;
-        if (errno == EINTR) continue;
-        if (errno == ETIMEDOUT) return false;
-        ABSL_RAW_LOG(FATAL, "sem_timedwait failed: %d", errno);
-      }
-    }
-    first_pass = false;
-  }
-}
-
-void Waiter::Post() {
-  // Post a wakeup.
-  if (wakeups_.fetch_add(1, std::memory_order_release) == 0) {
-    // We incremented from 0, need to wake a potential waiter.
-    Poke();
-  }
-}
-
-void Waiter::Poke() {
-  if (sem_post(&sem_) != 0) {  // Wake any semaphore waiter.
-    ABSL_RAW_LOG(FATAL, "sem_post failed with errno %d\n", errno);
-  }
-}
-
-#elif ABSL_WAITER_MODE == ABSL_WAITER_MODE_WIN32
-
-class Waiter::WinHelper {
- public:
-  static SRWLOCK *GetLock(Waiter *w) {
-    return reinterpret_cast<SRWLOCK *>(&w->mu_storage_);
-  }
-
-  static CONDITION_VARIABLE *GetCond(Waiter *w) {
-    return reinterpret_cast<CONDITION_VARIABLE *>(&w->cv_storage_);
-  }
-
-  static_assert(sizeof(SRWLOCK) == sizeof(void *),
-                "`mu_storage_` does not have the same size as SRWLOCK");
-  static_assert(alignof(SRWLOCK) == alignof(void *),
-                "`mu_storage_` does not have the same alignment as SRWLOCK");
-
-  static_assert(sizeof(CONDITION_VARIABLE) == sizeof(void *),
-                "`ABSL_CONDITION_VARIABLE_STORAGE` does not have the same size "
-                "as `CONDITION_VARIABLE`");
-  static_assert(
-      alignof(CONDITION_VARIABLE) == alignof(void *),
-      "`cv_storage_` does not have the same alignment as `CONDITION_VARIABLE`");
-
-  // The SRWLOCK and CONDITION_VARIABLE types must be trivially constructible
-  // and destructible because we never call their constructors or destructors.
-  static_assert(std::is_trivially_constructible<SRWLOCK>::value,
-                "The `SRWLOCK` type must be trivially constructible");
-  static_assert(
-      std::is_trivially_constructible<CONDITION_VARIABLE>::value,
-      "The `CONDITION_VARIABLE` type must be trivially constructible");
-  static_assert(std::is_trivially_destructible<SRWLOCK>::value,
-                "The `SRWLOCK` type must be trivially destructible");
-  static_assert(std::is_trivially_destructible<CONDITION_VARIABLE>::value,
-                "The `CONDITION_VARIABLE` type must be trivially destructible");
-};
-
-class LockHolder {
- public:
-  explicit LockHolder(SRWLOCK* mu) : mu_(mu) {
-    AcquireSRWLockExclusive(mu_);
-  }
-
-  LockHolder(const LockHolder&) = delete;
-  LockHolder& operator=(const LockHolder&) = delete;
-
-  ~LockHolder() {
-    ReleaseSRWLockExclusive(mu_);
-  }
-
- private:
-  SRWLOCK* mu_;
-};
-
-Waiter::Waiter() {
-  auto *mu = ::new (static_cast<void *>(&mu_storage_)) SRWLOCK;
-  auto *cv = ::new (static_cast<void *>(&cv_storage_)) CONDITION_VARIABLE;
-  InitializeSRWLock(mu);
-  InitializeConditionVariable(cv);
-  waiter_count_ = 0;
-  wakeup_count_ = 0;
-}
-
-// SRW locks and condition variables do not need to be explicitly destroyed.
-// https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-initializesrwlock
-// https://stackoverflow.com/questions/28975958/why-does-windows-have-no-deleteconditionvariable-function-to-go-together-with
-Waiter::~Waiter() = default;
-
-bool Waiter::Wait(KernelTimeout t) {
-  SRWLOCK *mu = WinHelper::GetLock(this);
-  CONDITION_VARIABLE *cv = WinHelper::GetCond(this);
-
-  LockHolder h(mu);
-  ++waiter_count_;
-
-  // Loop until we find a wakeup to consume or timeout.
-  // Note that, since the thread ticker is just reset, we don't need to check
-  // whether the thread is idle on the very first pass of the loop.
-  bool first_pass = true;
-  while (wakeup_count_ == 0) {
-    if (!first_pass) MaybeBecomeIdle();
-    // No wakeups available, time to wait.
-    if (!SleepConditionVariableSRW(cv, mu, t.InMillisecondsFromNow(), 0)) {
-      // GetLastError() returns a Win32 DWORD, but we assign to
-      // unsigned long to simplify the ABSL_RAW_LOG case below.  The uniform
-      // initialization guarantees this is not a narrowing conversion.
-      const unsigned long err{GetLastError()};  // NOLINT(runtime/int)
-      if (err == ERROR_TIMEOUT) {
-        --waiter_count_;
-        return false;
-      } else {
-        ABSL_RAW_LOG(FATAL, "SleepConditionVariableSRW failed: %lu", err);
-      }
-    }
-    first_pass = false;
-  }
-  // Consume a wakeup and we're done.
-  --wakeup_count_;
-  --waiter_count_;
-  return true;
-}
-
-void Waiter::Post() {
-  LockHolder h(WinHelper::GetLock(this));
-  ++wakeup_count_;
-  InternalCondVarPoke();
-}
-
-void Waiter::Poke() {
-  LockHolder h(WinHelper::GetLock(this));
-  InternalCondVarPoke();
-}
-
-void Waiter::InternalCondVarPoke() {
-  if (waiter_count_ != 0) {
-    WakeConditionVariable(WinHelper::GetCond(this));
-  }
-}
-
-#else
-#error Unknown ABSL_WAITER_MODE
-#endif
-
-}  // namespace synchronization_internal
-ABSL_NAMESPACE_END
-}  // namespace absl