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/*
* Copyright 2018, The Android Open Source Project
*
* Licensed 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 <chrono>
#include <vector>
#include <poll.h>
/* An interface for pollable classes.
*/
class Pollable {
public:
using Clock = std::chrono::steady_clock;
using Timestamp = Clock::time_point;
virtual ~Pollable() = default;
/* Get the poll data for the next poll loop. The implementation can place
* as many fds as needed in |fds|.
*/
virtual void getPollData(std::vector<pollfd>* fds) const = 0;
/* Get the timeout for the next poll loop. This should be a timestamp
* indicating when the timeout should be triggered. Note that this may
* be called at any time and any number of times for a poll loop so the
* deadline should not be adjusted in this call, a set deadline should
* just be returned. Note specifically that if a call to onReadAvailable
* modifies the deadline the timeout for the previous timestamp might not
* fire as the poller will check the timestamp AFTER onReadAvailable is
* called.
*/
virtual Timestamp getTimeout() const = 0;
/* Called when there is data available to read on an fd associated with
* the pollable. |fd| indicates which fd to read from. If the call returns
* false the poller will exit its poll loop with a return code of |status|.
*/
virtual bool onReadAvailable(int fd, int* status) = 0;
/* Called when an fd associated with the pollable is closed. |fd| indicates
* which fd was closed. If the call returns false the poller will exit its
* poll loop with a return code of |status|.
*/
virtual bool onClose(int fd, int* status) = 0;
/* Called when the timeout returned by getPollData has been reached. If
* the call returns false the poller will exit its poll loop with a return
* code of |status|.
*/
virtual bool onTimeout(int* status) = 0;
};
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