Packages
rocksdb
2.4.0
3.1.1
3.1.0
3.0.0
2.6.2
2.6.1
retired
2.6.0
retired
2.5.0
2.4.1
2.4.0
2.3.0
2.2.0
2.1.0
2.0.0
1.9.0
1.8.0
1.7.0
1.6.0
1.5.1
1.5.0
1.4.0
1.3.2
1.3.1
1.3.0
1.2.0
1.1.1
1.1.0
1.0.0
0.26.2
0.26.1
0.26.0
0.25.0
0.24.0
0.23.3
0.23.2
0.23.1
0.23.0
0.22.0
0.21.0
0.20.1
0.20.0
0.19.0
0.18.0
0.17.0
0.16.0
0.15.0
0.14.0
0.13.1
0.13.0
0.12.0
0.11.0
0.10.0
0.9.1
0.9.0
0.8.2
0.8.1
0.8.0
0.7.1
0.7.0
0.6.4
0.6.3
0.6.2
0.6.1
0.6.0
RocksDB for Erlang
Current section
Files
Jump to
Current section
Files
deps/rocksdb/util/single_thread_executor.h
// Copyright (c) Meta Platforms, Inc. and affiliates.
//
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
#pragma once
#if USE_COROUTINES
#include <atomic>
#include <queue>
#include "folly/CPortability.h"
#include "folly/CppAttributes.h"
#include "folly/Executor.h"
#include "util/async_file_reader.h"
namespace ROCKSDB_NAMESPACE {
// Implements a simple executor that runs callback functions in the same
// thread, unlike CPUThreadExecutor which may schedule the callback on
// another thread. Runs in a tight loop calling the queued callbacks,
// and polls for async IO completions when idle. The completions will
// resume suspended coroutines and they get added to the queue, which
// will get picked up by this loop.
// Any possibility of deadlock is precluded because the file system
// guarantees that async IO completion callbacks will not be scheduled
// to run in this thread or this executor.
class SingleThreadExecutor : public folly::Executor {
public:
explicit SingleThreadExecutor(AsyncFileReader& reader)
: reader_(reader), busy_(false) {}
void add(folly::Func callback) override {
auto& q = q_;
q.push(std::move(callback));
if (q.size() == 1 && !busy_) {
while (!q.empty()) {
q.front()();
q.pop();
if (q.empty()) {
// Prevent recursion, as the Wait may queue resumed coroutines
busy_ = true;
reader_.Wait();
busy_ = false;
}
}
}
}
private:
std::queue<folly::Func> q_;
AsyncFileReader& reader_;
bool busy_;
};
} // namespace ROCKSDB_NAMESPACE
#endif // USE_COROUTINES