84 lines
2.6 KiB
C++
84 lines
2.6 KiB
C++
/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "epoll.h"
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#include <sys/epoll.h>
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#include <chrono>
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#include <functional>
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#include <map>
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namespace android {
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namespace init {
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Epoll::Epoll() {}
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Result<Success> Epoll::Open() {
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if (epoll_fd_ >= 0) return Success();
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epoll_fd_.reset(epoll_create1(EPOLL_CLOEXEC));
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if (epoll_fd_ == -1) {
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return ErrnoError() << "epoll_create1 failed";
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}
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return Success();
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}
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Result<Success> Epoll::RegisterHandler(int fd, std::function<void()> handler) {
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auto [it, inserted] = epoll_handlers_.emplace(fd, std::move(handler));
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if (!inserted) {
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return Error() << "Cannot specify two epoll handlers for a given FD";
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}
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epoll_event ev;
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ev.events = EPOLLIN;
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// std::map's iterators do not get invalidated until erased, so we use the
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// pointer to the std::function in the map directly for epoll_ctl.
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ev.data.ptr = reinterpret_cast<void*>(&it->second);
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if (epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, fd, &ev) == -1) {
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Result<Success> result = ErrnoError() << "epoll_ctl failed to add fd";
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epoll_handlers_.erase(fd);
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return result;
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}
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return Success();
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}
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Result<Success> Epoll::UnregisterHandler(int fd) {
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if (epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, nullptr) == -1) {
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return ErrnoError() << "epoll_ctl failed to remove fd";
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}
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if (epoll_handlers_.erase(fd) != 1) {
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return Error() << "Attempting to remove epoll handler for FD without an existing handler";
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}
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return Success();
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}
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Result<Success> Epoll::Wait(std::optional<std::chrono::milliseconds> timeout) {
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int timeout_ms = -1;
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if (timeout && timeout->count() < INT_MAX) {
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timeout_ms = timeout->count();
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}
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epoll_event ev;
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auto nr = TEMP_FAILURE_RETRY(epoll_wait(epoll_fd_, &ev, 1, timeout_ms));
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if (nr == -1) {
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return ErrnoError() << "epoll_wait failed";
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} else if (nr == 1) {
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std::invoke(*reinterpret_cast<std::function<void()>*>(ev.data.ptr));
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}
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return Success();
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}
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} // namespace init
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} // namespace android
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