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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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
//
// http://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.
#pragma once
#include <functional>
#include <memory>
#include <unordered_map>
struct aeEventLoop;
namespace plasma {
// The constants below are defined using hardcoded values taken from ae.h so
// that ae.h does not need to be included in this file.
/// Constant specifying that the timer is done and it will be removed.
constexpr int kEventLoopTimerDone = -1; // AE_NOMORE
/// A successful status.
constexpr int kEventLoopOk = 0; // AE_OK
/// Read event on the file descriptor.
constexpr int kEventLoopRead = 1; // AE_READABLE
/// Write event on the file descriptor.
constexpr int kEventLoopWrite = 2; // AE_WRITABLE
typedef long long TimerID; // NOLINT
class EventLoop {
public:
// Signature of the handler that will be called when there is a new event
// on the file descriptor that this handler has been registered for.
//
// The arguments are the event flags (read or write).
using FileCallback = std::function<void(int)>;
// This handler will be called when a timer times out. The timer id is
// passed as an argument. The return is the number of milliseconds the timer
// shall be reset to or kEventLoopTimerDone if the timer shall not be
// triggered again.
using TimerCallback = std::function<int(int64_t)>;
EventLoop();
~EventLoop();
/// Add a new file event handler to the event loop.
///
/// \param fd The file descriptor we are listening to.
/// \param events The flags for events we are listening to (read or write).
/// \param callback The callback that will be called when the event happens.
/// \return Returns true if the event handler was added successfully.
bool AddFileEvent(int fd, int events, const FileCallback& callback);
/// Remove a file event handler from the event loop.
///
/// \param fd The file descriptor of the event handler.
void RemoveFileEvent(int fd);
/// Register a handler that will be called after a time slice of
/// "timeout" milliseconds.
///
/// \param timeout The timeout in milliseconds.
/// \param callback The callback for the timeout.
/// \return The ID of the newly created timer.
int64_t AddTimer(int64_t timeout, const TimerCallback& callback);
/// Remove a timer handler from the event loop.
///
/// \param timer_id The ID of the timer that is to be removed.
/// \return The ae.c error code. TODO(pcm): needs to be standardized
int RemoveTimer(int64_t timer_id);
/// \brief Run the event loop.
void Start();
/// \brief Stop the event loop
void Stop();
void Shutdown();
private:
static void FileEventCallback(aeEventLoop* loop, int fd, void* context, int events);
static int TimerEventCallback(aeEventLoop* loop, TimerID timer_id, void* context);
aeEventLoop* loop_;
std::unordered_map<int, std::unique_ptr<FileCallback>> file_callbacks_;
std::unordered_map<int64_t, std::unique_ptr<TimerCallback>> timer_callbacks_;
};
} // namespace plasma
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