io_result.h

#pragma once

#include <cstring>
#include <errno.h>
#include <string_view>

namespace quic {

// Return result from a read or write operation that wraps an errno value. It is implicitly
// convertible to bool to test for "is not an error" (which is the inverse of casting a plain
// integer error code value to bool).
struct io_result {
    // An error code, typically an errno value
    int error_code{0};
    // Returns true if this represent a successful result, i.e. an error_code of 0.
    operator bool() const { return error_code == 0; }

    // Returns true if this is an error value indicating a failure to write without blocking (only
    // applied to io_result's capturing an errno).
    bool blocked() const { return error_code == EAGAIN || error_code == EWOULDBLOCK; }

    // Returns the errno string for the given error code.
    std::string_view str() const { return strerror(error_code); }
};

}