vendor/anstyle-wincon-2.1.0/src/windows.rs

use std::os::windows::io::AsHandle;
use std::os::windows::io::AsRawHandle;

pub fn set_colors<S: AsHandle>(
    stream: &mut S,
    fg: anstyle::AnsiColor,
    bg: anstyle::AnsiColor,
) -> std::io::Result<()> {
    let handle = stream.as_handle();
    let handle = handle.as_raw_handle();
    let attributes = inner::set_colors(fg, bg);
    inner::set_console_text_attributes(handle, attributes)
}

pub fn get_colors<S: AsHandle>(
    stream: &S,
) -> std::io::Result<(anstyle::AnsiColor, anstyle::AnsiColor)> {
    let handle = stream.as_handle();
    let handle = handle.as_raw_handle();
    let info = inner::get_screen_buffer_info(handle)?;
    let (fg, bg) = inner::get_colors(&info);
    Ok((fg, bg))
}

mod inner {
    use windows_sys::Win32::System::Console::CONSOLE_CHARACTER_ATTRIBUTES;
    use windows_sys::Win32::System::Console::CONSOLE_SCREEN_BUFFER_INFO;
    use windows_sys::Win32::System::Console::FOREGROUND_BLUE;
    use windows_sys::Win32::System::Console::FOREGROUND_GREEN;
    use windows_sys::Win32::System::Console::FOREGROUND_INTENSITY;
    use windows_sys::Win32::System::Console::FOREGROUND_RED;

    use std::os::windows::io::RawHandle;

    const FOREGROUND_CYAN: CONSOLE_CHARACTER_ATTRIBUTES = FOREGROUND_BLUE | FOREGROUND_GREEN;
    const FOREGROUND_MAGENTA: CONSOLE_CHARACTER_ATTRIBUTES = FOREGROUND_BLUE | FOREGROUND_RED;
    const FOREGROUND_YELLOW: CONSOLE_CHARACTER_ATTRIBUTES = FOREGROUND_GREEN | FOREGROUND_RED;
    const FOREGROUND_WHITE: CONSOLE_CHARACTER_ATTRIBUTES =
        FOREGROUND_BLUE | FOREGROUND_GREEN | FOREGROUND_RED;

    pub fn get_screen_buffer_info(
        handle: RawHandle,
    ) -> std::io::Result<CONSOLE_SCREEN_BUFFER_INFO> {
        unsafe {
            let handle = std::mem::transmute(handle);
            if handle == 0 {
                return Err(std::io::Error::new(
                    std::io::ErrorKind::BrokenPipe,
                    "console is detached",
                ));
            }

            let mut info: CONSOLE_SCREEN_BUFFER_INFO = std::mem::zeroed();
            if windows_sys::Win32::System::Console::GetConsoleScreenBufferInfo(handle, &mut info)
                != 0
            {
                Ok(info)
            } else {
                Err(std::io::Error::last_os_error())
            }
        }
    }

    pub fn set_console_text_attributes(
        handle: RawHandle,
        attributes: CONSOLE_CHARACTER_ATTRIBUTES,
    ) -> std::io::Result<()> {
        unsafe {
            let handle = std::mem::transmute(handle);
            if handle == 0 {
                return Err(std::io::Error::new(
                    std::io::ErrorKind::BrokenPipe,
                    "console is detached",
                ));
            }

            if windows_sys::Win32::System::Console::SetConsoleTextAttribute(handle, attributes) != 0
            {
                Ok(())
            } else {
                Err(std::io::Error::last_os_error())
            }
        }
    }

    pub fn get_colors(
        info: &CONSOLE_SCREEN_BUFFER_INFO,
    ) -> (anstyle::AnsiColor, anstyle::AnsiColor) {
        let attributes = info.wAttributes;
        let bg = from_nibble(attributes >> 4);
        let fg = from_nibble(attributes);
        (fg, bg)
    }

    pub fn set_colors(
        fg: anstyle::AnsiColor,
        bg: anstyle::AnsiColor,
    ) -> CONSOLE_CHARACTER_ATTRIBUTES {
        to_nibble(bg) << 4 | to_nibble(fg)
    }

    fn from_nibble(color: CONSOLE_CHARACTER_ATTRIBUTES) -> anstyle::AnsiColor {
        if color & FOREGROUND_WHITE == FOREGROUND_WHITE {
            // 3 bits high
            anstyle::AnsiColor::White
        } else if color & FOREGROUND_CYAN == FOREGROUND_CYAN {
            // 2 bits high
            anstyle::AnsiColor::Cyan
        } else if color & FOREGROUND_YELLOW == FOREGROUND_YELLOW {
            // 2 bits high
            anstyle::AnsiColor::Yellow
        } else if color & FOREGROUND_MAGENTA == FOREGROUND_MAGENTA {
            // 2 bits high
            anstyle::AnsiColor::Magenta
        } else if color & FOREGROUND_RED == FOREGROUND_RED {
            // 1 bit high
            anstyle::AnsiColor::Red
        } else if color & FOREGROUND_GREEN == FOREGROUND_GREEN {
            // 1 bit high
            anstyle::AnsiColor::Green
        } else if color & FOREGROUND_BLUE == FOREGROUND_BLUE {
            // 1 bit high
            anstyle::AnsiColor::Blue
        } else {
            // 0 bits high
            anstyle::AnsiColor::Black
        }
        .bright(color & FOREGROUND_INTENSITY == FOREGROUND_INTENSITY)
    }

    fn to_nibble(color: anstyle::AnsiColor) -> CONSOLE_CHARACTER_ATTRIBUTES {
        let mut attributes = 0;
        attributes |= match color.bright(false) {
            anstyle::AnsiColor::Black => 0,
            anstyle::AnsiColor::Red => FOREGROUND_RED,
            anstyle::AnsiColor::Green => FOREGROUND_GREEN,
            anstyle::AnsiColor::Yellow => FOREGROUND_YELLOW,
            anstyle::AnsiColor::Blue => FOREGROUND_BLUE,
            anstyle::AnsiColor::Magenta => FOREGROUND_MAGENTA,
            anstyle::AnsiColor::Cyan => FOREGROUND_CYAN,
            anstyle::AnsiColor::White => FOREGROUND_WHITE,
            anstyle::AnsiColor::BrightBlack
            | anstyle::AnsiColor::BrightRed
            | anstyle::AnsiColor::BrightGreen
            | anstyle::AnsiColor::BrightYellow
            | anstyle::AnsiColor::BrightBlue
            | anstyle::AnsiColor::BrightMagenta
            | anstyle::AnsiColor::BrightCyan
            | anstyle::AnsiColor::BrightWhite => unreachable!("brights were toggled off"),
        };
        if color.is_bright() {
            attributes |= FOREGROUND_INTENSITY;
        }
        attributes
    }

    #[test]
    fn to_from_nibble() {
        const COLORS: [anstyle::AnsiColor; 16] = [
            anstyle::AnsiColor::Black,
            anstyle::AnsiColor::Red,
            anstyle::AnsiColor::Green,
            anstyle::AnsiColor::Yellow,
            anstyle::AnsiColor::Blue,
            anstyle::AnsiColor::Magenta,
            anstyle::AnsiColor::Cyan,
            anstyle::AnsiColor::White,
            anstyle::AnsiColor::BrightBlack,
            anstyle::AnsiColor::BrightRed,
            anstyle::AnsiColor::BrightGreen,
            anstyle::AnsiColor::BrightYellow,
            anstyle::AnsiColor::BrightBlue,
            anstyle::AnsiColor::BrightMagenta,
            anstyle::AnsiColor::BrightCyan,
            anstyle::AnsiColor::BrightWhite,
        ];
        for expected in COLORS {
            let nibble = to_nibble(expected);
            let actual = from_nibble(nibble);
            assert_eq!(expected, actual, "Intermediate: {}", nibble);
        }
    }
}