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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/message_loop/work_id_provider.h"
#include <memory>
#include "base/memory/ptr_util.h"
#include "base/no_destructor.h"
#include "base/threading/thread_local.h"
namespace base {
// static
WorkIdProvider* WorkIdProvider::GetForCurrentThread() {
static NoDestructor<ThreadLocalOwnedPointer<WorkIdProvider>> instance;
if (!instance->Get()) {
instance->Set(WrapUnique(new WorkIdProvider));
}
return instance->Get();
}
// This function must support being invoked while other threads are suspended so
// must not take any locks, including indirectly through use of heap allocation,
// LOG, CHECK, or DCHECK.
unsigned int WorkIdProvider::GetWorkId() {
return work_id_.load(std::memory_order_acquire);
}
WorkIdProvider::~WorkIdProvider() = default;
void WorkIdProvider::SetCurrentWorkIdForTesting(unsigned int id) {
work_id_.store(id, std::memory_order_relaxed);
}
void WorkIdProvider::IncrementWorkIdForTesting() {
IncrementWorkId();
}
WorkIdProvider::WorkIdProvider() : work_id_(0) {}
void WorkIdProvider::IncrementWorkId() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
unsigned int next_id = work_id_.load(std::memory_order_relaxed) + 1;
// Reserve 0 to mean no work items have been executed.
if (next_id == 0) {
++next_id;
}
// Release order ensures this state is visible to other threads prior to the
// following task/event execution.
work_id_.store(next_id, std::memory_order_release);
}
} // namespace base
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