git2cpp/src/utils/input_output.cpp at fa0279b878ad2263760ce72bac868161ee503318 · QuantStack/git2cpp · GitHub

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#include "input_output.hpp"

#include <iostream>

#include "ansi_code.hpp"

// OS-specific libraries.
#include <sys/ioctl.h>

unsigned int cursor_hider::s_scope_count = 0;

cursor_hider::cursor_hider(bool hide /* = true */)
    : m_hide(hide)
{
    s_scope_count++;
    write_ansi_code(m_hide);
}

cursor_hider::~cursor_hider()
{
    s_scope_count--;

    if (s_scope_count == 0)
    {
        // Ensure cursor is visible when git2cpp exits.
        write_ansi_code(false);
    }
    else
    {
        write_ansi_code(!m_hide);
    }
}

void cursor_hider::write_ansi_code(bool hide)
{
    std::cout << (hide ? ansi_code::hide_cursor : ansi_code::show_cursor);
}

alternative_buffer::alternative_buffer()
{
    tcgetattr(fileno(stdin), &m_previous_termios);
    auto new_termios = m_previous_termios;
    // Disable canonical mode (buffered I/O) and echo from stdin to stdout.
    new_termios.c_lflag &= (~ICANON & ~ECHO);
    tcsetattr(fileno(stdin), TCSANOW, &new_termios);

    std::cout << ansi_code::enable_alternative_buffer;
}

alternative_buffer::~alternative_buffer()
{
    std::cout << ansi_code::disable_alternative_buffer;

    // Restore previous termios settings.
    tcsetattr(fileno(stdin), TCSANOW, &m_previous_termios);
}

echo_control::echo_control(bool echo)
    : m_echo(echo)
{
    if (!m_echo)
    {
        tcgetattr(fileno(stdin), &m_previous_termios);
        auto new_termios = m_previous_termios;
        new_termios.c_lflag &= ~ECHO;
        tcsetattr(fileno(stdin), TCSANOW, &new_termios);
    }
}

echo_control::~echo_control()
{
    if (!m_echo)
    {
        // Restore previous termios settings.
        tcsetattr(fileno(stdin), TCSANOW, &m_previous_termios);
    }
}

std::string prompt_input(const std::string_view prompt, bool echo /* = true */)
{
    std::cout << prompt;

    echo_control ec(echo);
    std::string input;

    cursor_hider ch(false);  // Re-enable cursor if currently hidden.
    std::getline(std::cin, input);

    if (!echo)
    {
        std::cout << std::endl;
    }

    // Maybe sanitise input, removing escape codes?
    return input;
}

bool prompt_yes_or_no(const std::string_view prompt, bool default_return)
{
    while (true)
    {
        auto input = prompt_input(prompt);
        if (input.empty())
        {
            return default_return;
        }
        auto first_char = std::tolower(input.front());
        if (first_char == 'y')
        {
            return true;
        }
        else if (first_char == 'n')
        {
            return false;
        }
        // Repeat prompt.
    }
}