mirror of
https://github.com/facebook/rocksdb.git
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9277569ba3
Summary: Some files miss headers. Also some headers are irregular. Fix them to make an internal checkup tool happy. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10519 Reviewed By: jay-zhuang Differential Revision: D38603291 fbshipit-source-id: 13b1bbd6d48f5ee15ba20da67544396de48238f1
57 lines
1.7 KiB
C++
57 lines
1.7 KiB
C++
// Copyright (c) Meta Platforms, Inc. and affiliates.
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//
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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#pragma once
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#if USE_COROUTINES
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#include <atomic>
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#include "folly/CPortability.h"
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#include "folly/CppAttributes.h"
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#include "folly/Executor.h"
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#include "util/async_file_reader.h"
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namespace ROCKSDB_NAMESPACE {
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// Implements a simple executor that runs callback functions in the same
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// thread, unlike CPUThreadExecutor which may schedule the callback on
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// another thread. Runs in a tight loop calling the queued callbacks,
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// and polls for async IO completions when idle. The completions will
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// resume suspended coroutines and they get added to the queue, which
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// will get picked up by this loop.
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// Any possibility of deadlock is precluded because the file system
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// guarantees that async IO completion callbacks will not be scheduled
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// to run in this thread or this executor.
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class SingleThreadExecutor : public folly::Executor {
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public:
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explicit SingleThreadExecutor(AsyncFileReader& reader)
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: reader_(reader), busy_(false) {}
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void add(folly::Func callback) override {
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auto& q = q_;
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q.push(std::move(callback));
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if (q.size() == 1 && !busy_) {
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while (!q.empty()) {
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q.front()();
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q.pop();
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if (q.empty()) {
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// Prevent recursion, as the Wait may queue resumed coroutines
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busy_ = true;
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reader_.Wait();
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busy_ = false;
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}
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}
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}
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}
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private:
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std::queue<folly::Func> q_;
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AsyncFileReader& reader_;
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bool busy_;
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};
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} // namespace ROCKSDB_NAMESPACE
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#endif // USE_COROUTINES
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