12bc53e031
-- c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>: Remove a floating point division by zero test. This isn't testing behavior related to the library, and MSVC warns about it in opt mode. PiperOrigin-RevId: 285220804 -- 68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>: This CL introduces following changes to the class FlagImpl: * We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately. * CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now. * Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call. * We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced. PiperOrigin-RevId: 285132636 -- ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>: Change null-term* (and nul-term*) to NUL-term* in comments PiperOrigin-RevId: 285036610 -- 729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>: Use the Posix implementation of thread identity on MinGW. Some versions of MinGW suffer from thread_local bugs. PiperOrigin-RevId: 285022920 -- 39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>: Implementation detail change. Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil. PiperOrigin-RevId: 285012012 GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1
57 lines
1.8 KiB
C++
57 lines
1.8 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/synchronization/blocking_counter.h"
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#include "absl/base/internal/raw_logging.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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// Return whether int *arg is zero.
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static bool IsZero(void *arg) {
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return 0 == *reinterpret_cast<int *>(arg);
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}
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bool BlockingCounter::DecrementCount() {
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MutexLock l(&lock_);
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count_--;
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if (count_ < 0) {
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ABSL_RAW_LOG(
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FATAL,
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"BlockingCounter::DecrementCount() called too many times. count=%d",
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count_);
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}
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return count_ == 0;
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}
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void BlockingCounter::Wait() {
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MutexLock l(&this->lock_);
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ABSL_RAW_CHECK(count_ >= 0, "BlockingCounter underflow");
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// only one thread may call Wait(). To support more than one thread,
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// implement a counter num_to_exit, like in the Barrier class.
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ABSL_RAW_CHECK(num_waiting_ == 0, "multiple threads called Wait()");
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num_waiting_++;
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this->lock_.Await(Condition(IsZero, &this->count_));
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// At this point, We know that all threads executing DecrementCount have
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// released the lock, and so will not touch this object again.
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// Therefore, the thread calling this method is free to delete the object
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// after we return from this method.
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}
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ABSL_NAMESPACE_END
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} // namespace absl
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