FileReader.cpp

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/*
 * SNode.C - a slim toolkit for network communication
 * Copyright (C) Volker Christian <me@vchrist.at>
 *               2020, 2021, 2022, 2023, 2024, 2025
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "core/file/FileReader.h"
 
#include "core/State.h"
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#include "core/system/unistd.h"
 
#include <cerrno>
#include <vector>
 
#endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
constexpr int MF_READSIZE = 16384;
 
namespace core::file {
 
    FileReader::FileReader(int fd, const std::string& name, std::size_t pufferSize, int openErrno)
        : core::Descriptor(fd)
        , EventReceiver(name)
        , pufferSize(pufferSize)
        , openErrno(openErrno) {
    }
 
    FileReader* FileReader::open(const std::string& path) {
        errno = 0;
 
        const int fd = core::system::open(path.c_str(), O_RDONLY);
 
        return new FileReader(fd, "FileReader: " + path, MF_READSIZE, fd < 0 ? errno : 0);
    }
 
    bool FileReader::isOpen() {
        return getFd() >= 0;
    }
 
    void FileReader::onEvent([[maybe_unused]] const utils::Timeval& currentTime) {
        if (running && core::eventLoopState() != core::State::STOPPING) {
            if (!suspended) {
                std::vector<char> puffer(pufferSize);
 
                const ssize_t ret = core::system::read(getFd(), puffer.data(), puffer.capacity());
                if (ret > 0) {
                    if (this->send(puffer.data(), static_cast<std::size_t>(ret)) < 0) {
                        running = false;
 
                        this->error(errno);
                    }
                } else {
                    running = false;
 
                    if (ret == 0) {
                        this->eof();
                    } else {
                        this->error(errno);
                    }
                }
 
                span();
            }
        } else {
            delete this;
        }
    }
 
    void FileReader::start() {
        if (!running) {
            running = true;
            span();
        }
    }
 
    void FileReader::suspend() {
        if (running) {
            suspended = true;
        }
    }
 
    void FileReader::resume() {
        if (running) {
            suspended = false;
            span();
        }
    }
 
    void FileReader::stop() {
        if (running) {
            this->eof();
 
            running = false;
            span();
        }
    }
 
} // namespace core::file