// system headers

#include <algorithm>

#include <fcntl.h>

#include <unistd.h>

#include <functional>

#include <cstring>

#include <stdexcept>

// local headers

#include "linuxdeploy/subprocess/pipe_reader.h"

pipe_reader::pipe_reader(int pipe_fd) : pipe_fd_(pipe_fd) {

// add O_NONBLOCK TO fd's flags to be able to read

auto flags = fcntl(pipe_fd_, F_GETFL, 0);

flags |= O_NONBLOCK;

fcntl(pipe_fd_, F_SETFL, flags);

}

size_t pipe_reader::read(std::vector<std::string::value_type>& buffer) const {

ssize_t rv = ::read(pipe_fd_, buffer.data(), buffer.size());

if (rv == -1) {

// no data available

if (errno == EAGAIN)

return 0;

// TODO: introduce custom subprocess_error

throw std::runtime_error{"unexpected error reading from pipe: " + std::string(strerror(errno))};

}

return rv;

}