#pragma once

#include <string>

#include <set>

#include <vector>

#include <poll.h>

#include <chrono>

/**

* Reads from a pipe when data is available, and hands data to registered callbacks.

*/

class pipe_reader {

private:

struct pollfd pollfd_;

public:

static constexpr std::chrono::milliseconds READ_TIMEOUT{50};

enum class result {

SUCCESS = 0,

TIMEOUT,

END_OF_FILE,

};

/**

* Construct new instance from pipe file descriptor.

* @param pipe_fd file descriptor for pipe we will read from (e.g., a subprocess's stdout, stderr pipes)

*/

explicit pipe_reader(int pipe_fd);

/**

* Read from pipe file descriptor and store data in buffer.

* This method is non-blocking, i.e., if there is no data to read, it returns immediately.

* Otherwise, it will read until either of the following conditions is met:

*

* - no more data left in the pipe to be read

* - buffer is completely filled

*

* The buffer will be resized to the number of bytes read from the pipe.

*

* On errors, a subprocess_error is thrown.

*

* @param buffer buffer to store read data into

* @returns

*/

result read(std::vector<std::string::value_type>& buffer, std::chrono::milliseconds read_timeout = READ_TIMEOUT);

};