Boost::Process Pipe 流和單元測試

Question

我有兩個 stream 這樣的來源：

bp::ipstream StdOut;
bp::opstream StdIn;
bp::child MyProcess = bp::child(processPath, bp::std_out > StdOut, bp::std_in < StdIn);
// Doing some stuff with StdOut and StdIn

我想知道是否有辦法手動寫入這個 StdOut 並從 StdIn 讀取以進行單元測試？ 非常感謝！

Answer 1

您可以像普通的 stream 一樣寫信給他們：

住在科利魯

#include <boost/process.hpp>
#include <iostream>

namespace bp = boost::process;

int main() {
    bp::ipstream StdOut;
    bp::opstream StdIn;
    bp::child MyProcess = bp::child("/usr/bin/rev", bp::std_out > StdOut, bp::std_in < StdIn);

    for (int i = 0; i<100; ++i) {
        StdIn << "Sure no problem, " << i << std::endl;
    }
    StdIn.flush();
    StdIn.pipe().close();

    std::string il;
    while (getline(StdOut, il)) {
        std::cout << il << std::endl;
    }

    std::cout << "Bye\n";
}

印刷

0 ,melborp on eruS
1 ,melborp on eruS
2 ,melborp on eruS
...
99 ,melborp on eruS
Bye

異步版本

請注意，就像文檔警告的那樣，如果您的進程需要異步 IO 您最終可能會出現死鎖（例如，在子進程等待輸入時等待 output）。

為此，請使用 Asio 的異步操作：

住在科利魯

#include <boost/process.hpp>
#include <boost/asio.hpp>
#include <boost/process/async.hpp>
#include <iostream>

namespace ba = boost::asio;
namespace bp = boost::process;

int main() {
    ba::io_context io;
    bp::async_pipe ip(io), op(io);
    //bp::async_pipe StdIn(io);

    bp::child MyProcess = bp::child("/usr/bin/tac", bp::std_out > op, bp::std_in < ip, io);

    std::function<void()> send_loop, recv_loop;

    ba::streambuf sb;
    send_loop = [&, i=0]() mutable {
        if (++i<100) {
            std::ostream(&sb) << "Sure no problem, " << i << std::endl;
            ba::async_write(ip, sb, [&send_loop](auto ec, auto /*tx*/) {
                //std::cout << "Sent " << tx << " bytes (" << ec.message() << ")\n";
                if (!ec) send_loop();
            });
        } else ip.close();
    };

    ba::streambuf rb;
    recv_loop = [&]() {
        ba::async_read_until(op, rb, "\n", [&](auto ec, auto /*tx*/) {
            //std::cout << "Received " << tx << " bytes (" << ec.message() << ")\n";
            std::cout << &rb << std::flush;
            if (!ec) recv_loop();
        });
    };

    io.post(send_loop);
    io.post(recv_loop);
    io.run();

    std::cout << "Bye\n";
}

打印預期：

Sure no problem, 99
Sure no problem, 98
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