tokenpipe.h

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// Copyright (c) 2021 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#ifndef BITCOIN_UTIL_TOKENPIPE_H
#define BITCOIN_UTIL_TOKENPIPE_H
 
#ifndef WIN32
 
#include <cstdint>
#include <optional>
 
class TokenPipeEnd {
private:
    int m_fd = -1;
 
public:
    TokenPipeEnd(int fd = -1);
    ~TokenPipeEnd();
 
    enum Status {
        TS_ERR = -1,
        TS_EOS = -2,
    };
 
    int TokenWrite(uint8_t token);
 
    int TokenRead();
 
    void Close();
 
    bool IsOpen() { return m_fd != -1; }
 
    // Move-only class.
    TokenPipeEnd(TokenPipeEnd &&other) {
        m_fd = other.m_fd;
        other.m_fd = -1;
    }
    TokenPipeEnd &operator=(TokenPipeEnd &&other) {
        Close();
        m_fd = other.m_fd;
        other.m_fd = -1;
        return *this;
    }
    TokenPipeEnd(const TokenPipeEnd &) = delete;
    TokenPipeEnd &operator=(const TokenPipeEnd &) = delete;
};
 
class TokenPipe {
private:
    int m_fds[2] = {-1, -1};
 
    TokenPipe(int fds[2]) : m_fds{fds[0], fds[1]} {}
 
public:
    ~TokenPipe();
 
    static std::optional<TokenPipe> Make();
 
    TokenPipeEnd TakeReadEnd();
 
    TokenPipeEnd TakeWriteEnd();
 
    void Close();
 
    // Move-only class.
    TokenPipe(TokenPipe &&other) {
        for (int i = 0; i < 2; ++i) {
            m_fds[i] = other.m_fds[i];
            other.m_fds[i] = -1;
        }
    }
    TokenPipe &operator=(TokenPipe &&other) {
        Close();
        for (int i = 0; i < 2; ++i) {
            m_fds[i] = other.m_fds[i];
            other.m_fds[i] = -1;
        }
        return *this;
    }
    TokenPipe(const TokenPipe &) = delete;
    TokenPipe &operator=(const TokenPipe &) = delete;
};
 
#endif // WIN32
 
#endif // BITCOIN_UTIL_TOKENPIPE_H