chore(3p/abseil_cpp): unvendor abseil_cpp r/3786

we weren't actually using these sources anymore, okay?

Change-Id: If701571d9716de308d3512e1eb22c35db0877a66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5248
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>

1 files changed, 0 insertions, 226 deletions

diff --git a/third_party/abseil_cpp/absl/base/call_once.h b/third_party/abseil_cpp/absl/base/call_once.h
deleted file mode 100644
index 5b468af855f1..000000000000
--- a/third_party/abseil_cpp/absl/base/call_once.h
+++ /dev/null
@@ -1,226 +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.
-//
-// -----------------------------------------------------------------------------
-// File: call_once.h
-// -----------------------------------------------------------------------------
-//
-// This header file provides an Abseil version of `std::call_once` for invoking
-// a given function at most once, across all threads. This Abseil version is
-// faster than the C++11 version and incorporates the C++17 argument-passing
-// fix, so that (for example) non-const references may be passed to the invoked
-// function.
-
-#ifndef ABSL_BASE_CALL_ONCE_H_
-#define ABSL_BASE_CALL_ONCE_H_
-
-#include <algorithm>
-#include <atomic>
-#include <cstdint>
-#include <type_traits>
-#include <utility>
-
-#include "absl/base/internal/invoke.h"
-#include "absl/base/internal/low_level_scheduling.h"
-#include "absl/base/internal/raw_logging.h"
-#include "absl/base/internal/scheduling_mode.h"
-#include "absl/base/internal/spinlock_wait.h"
-#include "absl/base/macros.h"
-#include "absl/base/optimization.h"
-#include "absl/base/port.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-
-class once_flag;
-
-namespace base_internal {
-std::atomic<uint32_t>* ControlWord(absl::once_flag* flag);
-}  // namespace base_internal
-
-// call_once()
-//
-// For all invocations using a given `once_flag`, invokes a given `fn` exactly
-// once across all threads. The first call to `call_once()` with a particular
-// `once_flag` argument (that does not throw an exception) will run the
-// specified function with the provided `args`; other calls with the same
-// `once_flag` argument will not run the function, but will wait
-// for the provided function to finish running (if it is still running).
-//
-// This mechanism provides a safe, simple, and fast mechanism for one-time
-// initialization in a multi-threaded process.
-//
-// Example:
-//
-// class MyInitClass {
-//  public:
-//  ...
-//  mutable absl::once_flag once_;
-//
-//  MyInitClass* init() const {
-//    absl::call_once(once_, &MyInitClass::Init, this);
-//    return ptr_;
-//  }
-//
-template <typename Callable, typename... Args>
-void call_once(absl::once_flag& flag, Callable&& fn, Args&&... args);
-
-// once_flag
-//
-// Objects of this type are used to distinguish calls to `call_once()` and
-// ensure the provided function is only invoked once across all threads. This
-// type is not copyable or movable. However, it has a `constexpr`
-// constructor, and is safe to use as a namespace-scoped global variable.
-class once_flag {
- public:
-  constexpr once_flag() : control_(0) {}
-  once_flag(const once_flag&) = delete;
-  once_flag& operator=(const once_flag&) = delete;
-
- private:
-  friend std::atomic<uint32_t>* base_internal::ControlWord(once_flag* flag);
-  std::atomic<uint32_t> control_;
-};
-
-//------------------------------------------------------------------------------
-// End of public interfaces.
-// Implementation details follow.
-//------------------------------------------------------------------------------
-
-namespace base_internal {
-
-// Like call_once, but uses KERNEL_ONLY scheduling. Intended to be used to
-// initialize entities used by the scheduler implementation.
-template <typename Callable, typename... Args>
-void LowLevelCallOnce(absl::once_flag* flag, Callable&& fn, Args&&... args);
-
-// Disables scheduling while on stack when scheduling mode is non-cooperative.
-// No effect for cooperative scheduling modes.
-class SchedulingHelper {
- public:
-  explicit SchedulingHelper(base_internal::SchedulingMode mode) : mode_(mode) {
-    if (mode_ == base_internal::SCHEDULE_KERNEL_ONLY) {
-      guard_result_ = base_internal::SchedulingGuard::DisableRescheduling();
-    }
-  }
-
-  ~SchedulingHelper() {
-    if (mode_ == base_internal::SCHEDULE_KERNEL_ONLY) {
-      base_internal::SchedulingGuard::EnableRescheduling(guard_result_);
-    }
-  }
-
- private:
-  base_internal::SchedulingMode mode_;
-  bool guard_result_;
-};
-
-// Bit patterns for call_once state machine values.  Internal implementation
-// detail, not for use by clients.
-//
-// The bit patterns are arbitrarily chosen from unlikely values, to aid in
-// debugging.  However, kOnceInit must be 0, so that a zero-initialized
-// once_flag will be valid for immediate use.
-enum {
-  kOnceInit = 0,
-  kOnceRunning = 0x65C2937B,
-  kOnceWaiter = 0x05A308D2,
-  // A very small constant is chosen for kOnceDone so that it fit in a single
-  // compare with immediate instruction for most common ISAs.  This is verified
-  // for x86, POWER and ARM.
-  kOnceDone = 221,    // Random Number
-};
-
-template <typename Callable, typename... Args>
-ABSL_ATTRIBUTE_NOINLINE
-void CallOnceImpl(std::atomic<uint32_t>* control,
-                  base_internal::SchedulingMode scheduling_mode, Callable&& fn,
-                  Args&&... args) {
-#ifndef NDEBUG
-  {
-    uint32_t old_control = control->load(std::memory_order_relaxed);
-    if (old_control != kOnceInit &&
-        old_control != kOnceRunning &&
-        old_control != kOnceWaiter &&
-        old_control != kOnceDone) {
-      ABSL_RAW_LOG(FATAL, "Unexpected value for control word: 0x%lx",
-                   static_cast<unsigned long>(old_control));  // NOLINT
-    }
-  }
-#endif  // NDEBUG
-  static const base_internal::SpinLockWaitTransition trans[] = {
-      {kOnceInit, kOnceRunning, true},
-      {kOnceRunning, kOnceWaiter, false},
-      {kOnceDone, kOnceDone, true}};
-
-  // Must do this before potentially modifying control word's state.
-  base_internal::SchedulingHelper maybe_disable_scheduling(scheduling_mode);
-  // Short circuit the simplest case to avoid procedure call overhead.
-  // The base_internal::SpinLockWait() call returns either kOnceInit or
-  // kOnceDone. If it returns kOnceDone, it must have loaded the control word
-  // with std::memory_order_acquire and seen a value of kOnceDone.
-  uint32_t old_control = kOnceInit;
-  if (control->compare_exchange_strong(old_control, kOnceRunning,
-                                       std::memory_order_relaxed) ||
-      base_internal::SpinLockWait(control, ABSL_ARRAYSIZE(trans), trans,
-                                  scheduling_mode) == kOnceInit) {
-    base_internal::invoke(std::forward<Callable>(fn),
-                          std::forward<Args>(args)...);
-    // The call to SpinLockWake below is an optimization, because the waiter
-    // in SpinLockWait is waiting with a short timeout. The atomic load/store
-    // sequence is slightly faster than an atomic exchange:
-    //   old_control = control->exchange(base_internal::kOnceDone,
-    //                                   std::memory_order_release);
-    // We opt for a slightly faster case when there are no waiters, in spite
-    // of longer tail latency when there are waiters.
-    old_control = control->load(std::memory_order_relaxed);
-    control->store(base_internal::kOnceDone, std::memory_order_release);
-    if (old_control == base_internal::kOnceWaiter) {
-      base_internal::SpinLockWake(control, true);
-    }
-  }  // else *control is already kOnceDone
-}
-
-inline std::atomic<uint32_t>* ControlWord(once_flag* flag) {
-  return &flag->control_;
-}
-
-template <typename Callable, typename... Args>
-void LowLevelCallOnce(absl::once_flag* flag, Callable&& fn, Args&&... args) {
-  std::atomic<uint32_t>* once = base_internal::ControlWord(flag);
-  uint32_t s = once->load(std::memory_order_acquire);
-  if (ABSL_PREDICT_FALSE(s != base_internal::kOnceDone)) {
-    base_internal::CallOnceImpl(once, base_internal::SCHEDULE_KERNEL_ONLY,
-                                std::forward<Callable>(fn),
-                                std::forward<Args>(args)...);
-  }
-}
-
-}  // namespace base_internal
-
-template <typename Callable, typename... Args>
-void call_once(absl::once_flag& flag, Callable&& fn, Args&&... args) {
-  std::atomic<uint32_t>* once = base_internal::ControlWord(&flag);
-  uint32_t s = once->load(std::memory_order_acquire);
-  if (ABSL_PREDICT_FALSE(s != base_internal::kOnceDone)) {
-    base_internal::CallOnceImpl(
-        once, base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL,
-        std::forward<Callable>(fn), std::forward<Args>(args)...);
-  }
-}
-
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_BASE_CALL_ONCE_H_