ghostty-rs/crates/ghostty-input/src/key.rs

//! Key events and key codes (ZIG/src/input/key.zig).
//!
//! The Zig `imguiKey` helper (cimgui constants) is intentionally not ported;
//! the inspector is deferred (see notes).

pub use crate::key_mods::Mods;

/// A generic key input event. This is the information that is necessary
/// regardless of apprt in order to generate the proper terminal
/// control sequences for a given key press.
///
/// Some apprts may not be able to provide all of this information, such
/// as GLFW. In this case, the apprt should provide as much information
/// as it can and it should be expected that the terminal behavior
/// will not be totally correct.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct KeyEvent<'a> {
    /// The action: press, release, etc.
    pub action: Action,

    /// The keycode of the physical key that was pressed. This is agnostic
    /// to the layout. Layout-dependent matching can only be done via the
    /// UTF-8 or unshifted codepoint.
    pub key: Key,

    /// Mods are the modifiers that are pressed.
    pub mods: Mods,

    /// The mods that were consumed in order to generate the text
    /// in utf8. This has the mods set that were consumed, so to
    /// get the set of mods that are effective you must negate
    /// mods with this.
    ///
    /// This field is meaningless if utf8 is empty.
    pub consumed_mods: Mods,

    /// Composing is true when this key event is part of a dead key
    /// composition sequence and we're in the middle of it.
    pub composing: bool,

    /// The utf8 sequence that was generated by this key event.
    /// This will be an empty string if there is no text generated.
    /// If composing is true and this is non-empty, this is preedit
    /// text.
    pub utf8: &'a str,

    /// The codepoint for this key when it is unshifted. For example,
    /// shift+a is "A" in UTF-8 but unshifted would provide 'a'.
    pub unshifted_codepoint: u32,
}

impl Default for KeyEvent<'_> {
    fn default() -> Self {
        KeyEvent {
            action: Action::Press,
            key: Key::Unidentified,
            mods: Mods::default(),
            consumed_mods: Mods::default(),
            composing: false,
            utf8: "",
            unshifted_codepoint: 0,
        }
    }
}

impl KeyEvent<'_> {
    /// Returns the effective modifiers for this event. The effective
    /// modifiers are the mods that should be considered for keybindings.
    pub fn effective_mods(&self) -> Mods {
        if self.utf8.is_empty() {
            return self.mods;
        }
        self.mods.unset(self.consumed_mods)
    }

    /// Returns a unique hash for this key event to be used for tracking
    /// uniquess specifically with bindings. This omits fields that are
    /// irrelevant for bindings.
    pub fn binding_hash(&self) -> u64 {
        use std::hash::{Hash, Hasher};
        let mut hasher = std::collections::hash_map::DefaultHasher::new();

        // These are all the fields that are explicitly part of Trigger.
        self.key.hash(&mut hasher);
        self.unshifted_codepoint.hash(&mut hasher);
        self.mods.binding().hash(&mut hasher);

        // Notes on unmapped things and why:
        //
        // - action: we don't have action-specific bindings right now
        //   AND we want to know if a key resulted in a binding regardless
        //   of action because a press should also ignore a release and so on.
        //
        // We can add to this if there is other confusion.

        hasher.finish()
    }
}

/// The action associated with an input event.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
#[repr(i32)]
pub enum Action {
    Release,
    Press,
    Repeat,
}

macro_rules! define_keys {
    ($($variant:ident => $name:literal,)*) => {
        /// The set of key codes that Ghostty is aware of. These represent
        /// physical keys on the keyboard. The logical key (or key string)
        /// is the string that is generated by the key event and that is up
        /// to the apprt to provide.
        ///
        /// Note that these are layout-independent. For example, the "a"
        /// key on a US keyboard is the same as the "ф" key on a Russian
        /// keyboard, but both will report the "a" enum value in the key
        /// event. These values are based on the W3C standard. See:
        /// https://www.w3.org/TR/uievents-code
        ///
        /// Layout-dependent strings are provided in the KeyEvent struct as
        /// UTF-8 and are produced by the associated apprt. Ghostty core has
        /// no mechanism to map input events to strings without the apprt.
        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
        #[repr(i32)]
        pub enum Key {
            $($variant,)*
        }

        impl Key {
            /// All keys in declaration order.
            pub const ALL: &'static [Key] = &[$(Key::$variant,)*];

            /// The Zig tag name (snake_case) of this key.
            pub fn name(self) -> &'static str {
                match self {
                    $(Key::$variant => $name,)*
                }
            }

            /// Look up a key by its Zig tag name (snake_case).
            pub fn from_name(s: &str) -> Option<Key> {
                match s {
                    $($name => Some(Key::$variant),)*
                    _ => None,
                }
            }
        }
    };
}

define_keys! {
        Unidentified => "unidentified",
        Backquote => "backquote",
        Backslash => "backslash",
        BracketLeft => "bracket_left",
        BracketRight => "bracket_right",
        Comma => "comma",
        Digit0 => "digit_0",
        Digit1 => "digit_1",
        Digit2 => "digit_2",
        Digit3 => "digit_3",
        Digit4 => "digit_4",
        Digit5 => "digit_5",
        Digit6 => "digit_6",
        Digit7 => "digit_7",
        Digit8 => "digit_8",
        Digit9 => "digit_9",
        Equal => "equal",
        IntlBackslash => "intl_backslash",
        IntlRo => "intl_ro",
        IntlYen => "intl_yen",
        KeyA => "key_a",
        KeyB => "key_b",
        KeyC => "key_c",
        KeyD => "key_d",
        KeyE => "key_e",
        KeyF => "key_f",
        KeyG => "key_g",
        KeyH => "key_h",
        KeyI => "key_i",
        KeyJ => "key_j",
        KeyK => "key_k",
        KeyL => "key_l",
        KeyM => "key_m",
        KeyN => "key_n",
        KeyO => "key_o",
        KeyP => "key_p",
        KeyQ => "key_q",
        KeyR => "key_r",
        KeyS => "key_s",
        KeyT => "key_t",
        KeyU => "key_u",
        KeyV => "key_v",
        KeyW => "key_w",
        KeyX => "key_x",
        KeyY => "key_y",
        KeyZ => "key_z",
        Minus => "minus",
        Period => "period",
        Quote => "quote",
        Semicolon => "semicolon",
        Slash => "slash",
        AltLeft => "alt_left",
        AltRight => "alt_right",
        Backspace => "backspace",
        CapsLock => "caps_lock",
        ContextMenu => "context_menu",
        ControlLeft => "control_left",
        ControlRight => "control_right",
        Enter => "enter",
        MetaLeft => "meta_left",
        MetaRight => "meta_right",
        ShiftLeft => "shift_left",
        ShiftRight => "shift_right",
        Space => "space",
        Tab => "tab",
        Convert => "convert",
        KanaMode => "kana_mode",
        NonConvert => "non_convert",
        Delete => "delete",
        End => "end",
        Help => "help",
        Home => "home",
        Insert => "insert",
        PageDown => "page_down",
        PageUp => "page_up",
        ArrowDown => "arrow_down",
        ArrowLeft => "arrow_left",
        ArrowRight => "arrow_right",
        ArrowUp => "arrow_up",
        NumLock => "num_lock",
        Numpad0 => "numpad_0",
        Numpad1 => "numpad_1",
        Numpad2 => "numpad_2",
        Numpad3 => "numpad_3",
        Numpad4 => "numpad_4",
        Numpad5 => "numpad_5",
        Numpad6 => "numpad_6",
        Numpad7 => "numpad_7",
        Numpad8 => "numpad_8",
        Numpad9 => "numpad_9",
        NumpadAdd => "numpad_add",
        NumpadBackspace => "numpad_backspace",
        NumpadClear => "numpad_clear",
        NumpadClearEntry => "numpad_clear_entry",
        NumpadComma => "numpad_comma",
        NumpadDecimal => "numpad_decimal",
        NumpadDivide => "numpad_divide",
        NumpadEnter => "numpad_enter",
        NumpadEqual => "numpad_equal",
        NumpadMemoryAdd => "numpad_memory_add",
        NumpadMemoryClear => "numpad_memory_clear",
        NumpadMemoryRecall => "numpad_memory_recall",
        NumpadMemoryStore => "numpad_memory_store",
        NumpadMemorySubtract => "numpad_memory_subtract",
        NumpadMultiply => "numpad_multiply",
        NumpadParenLeft => "numpad_paren_left",
        NumpadParenRight => "numpad_paren_right",
        NumpadSubtract => "numpad_subtract",
        NumpadSeparator => "numpad_separator",
        NumpadUp => "numpad_up",
        NumpadDown => "numpad_down",
        NumpadRight => "numpad_right",
        NumpadLeft => "numpad_left",
        NumpadBegin => "numpad_begin",
        NumpadHome => "numpad_home",
        NumpadEnd => "numpad_end",
        NumpadInsert => "numpad_insert",
        NumpadDelete => "numpad_delete",
        NumpadPageUp => "numpad_page_up",
        NumpadPageDown => "numpad_page_down",
        Escape => "escape",
        F1 => "f1",
        F2 => "f2",
        F3 => "f3",
        F4 => "f4",
        F5 => "f5",
        F6 => "f6",
        F7 => "f7",
        F8 => "f8",
        F9 => "f9",
        F10 => "f10",
        F11 => "f11",
        F12 => "f12",
        F13 => "f13",
        F14 => "f14",
        F15 => "f15",
        F16 => "f16",
        F17 => "f17",
        F18 => "f18",
        F19 => "f19",
        F20 => "f20",
        F21 => "f21",
        F22 => "f22",
        F23 => "f23",
        F24 => "f24",
        F25 => "f25",
        Fn => "fn",
        FnLock => "fn_lock",
        PrintScreen => "print_screen",
        ScrollLock => "scroll_lock",
        Pause => "pause",
        BrowserBack => "browser_back",
        BrowserFavorites => "browser_favorites",
        BrowserForward => "browser_forward",
        BrowserHome => "browser_home",
        BrowserRefresh => "browser_refresh",
        BrowserSearch => "browser_search",
        BrowserStop => "browser_stop",
        Eject => "eject",
        LaunchApp1 => "launch_app_1",
        LaunchApp2 => "launch_app_2",
        LaunchMail => "launch_mail",
        MediaPlayPause => "media_play_pause",
        MediaSelect => "media_select",
        MediaStop => "media_stop",
        MediaTrackNext => "media_track_next",
        MediaTrackPrevious => "media_track_previous",
        Power => "power",
        Sleep => "sleep",
        AudioVolumeDown => "audio_volume_down",
        AudioVolumeMute => "audio_volume_mute",
        AudioVolumeUp => "audio_volume_up",
        WakeUp => "wake_up",
        Copy => "copy",
        Cut => "cut",
        Paste => "paste",
}

/// Codepoint <-> key map. Keypad entries must always be last so that
/// `from_ascii` doesn't map them over normal numerics and other keys.
const CODEPOINT_MAP: &[(u32, Key)] = &[
    ('a' as u32, Key::KeyA),
    ('b' as u32, Key::KeyB),
    ('c' as u32, Key::KeyC),
    ('d' as u32, Key::KeyD),
    ('e' as u32, Key::KeyE),
    ('f' as u32, Key::KeyF),
    ('g' as u32, Key::KeyG),
    ('h' as u32, Key::KeyH),
    ('i' as u32, Key::KeyI),
    ('j' as u32, Key::KeyJ),
    ('k' as u32, Key::KeyK),
    ('l' as u32, Key::KeyL),
    ('m' as u32, Key::KeyM),
    ('n' as u32, Key::KeyN),
    ('o' as u32, Key::KeyO),
    ('p' as u32, Key::KeyP),
    ('q' as u32, Key::KeyQ),
    ('r' as u32, Key::KeyR),
    ('s' as u32, Key::KeyS),
    ('t' as u32, Key::KeyT),
    ('u' as u32, Key::KeyU),
    ('v' as u32, Key::KeyV),
    ('w' as u32, Key::KeyW),
    ('x' as u32, Key::KeyX),
    ('y' as u32, Key::KeyY),
    ('z' as u32, Key::KeyZ),
    ('0' as u32, Key::Digit0),
    ('1' as u32, Key::Digit1),
    ('2' as u32, Key::Digit2),
    ('3' as u32, Key::Digit3),
    ('4' as u32, Key::Digit4),
    ('5' as u32, Key::Digit5),
    ('6' as u32, Key::Digit6),
    ('7' as u32, Key::Digit7),
    ('8' as u32, Key::Digit8),
    ('9' as u32, Key::Digit9),
    (';' as u32, Key::Semicolon),
    (' ' as u32, Key::Space),
    ('\'' as u32, Key::Quote),
    (',' as u32, Key::Comma),
    ('`' as u32, Key::Backquote),
    ('.' as u32, Key::Period),
    ('/' as u32, Key::Slash),
    ('-' as u32, Key::Minus),
    ('=' as u32, Key::Equal),
    ('[' as u32, Key::BracketLeft),
    (']' as u32, Key::BracketRight),
    ('\\' as u32, Key::Backslash),
    // Control characters
    ('\t' as u32, Key::Tab),
    // Keypad entries. We just assume keypad with the numpad_ prefix
    // so that has some special meaning.
    ('0' as u32, Key::Numpad0),
    ('1' as u32, Key::Numpad1),
    ('2' as u32, Key::Numpad2),
    ('3' as u32, Key::Numpad3),
    ('4' as u32, Key::Numpad4),
    ('5' as u32, Key::Numpad5),
    ('6' as u32, Key::Numpad6),
    ('7' as u32, Key::Numpad7),
    ('8' as u32, Key::Numpad8),
    ('9' as u32, Key::Numpad9),
    ('.' as u32, Key::NumpadDecimal),
    ('/' as u32, Key::NumpadDivide),
    ('*' as u32, Key::NumpadMultiply),
    ('-' as u32, Key::NumpadSubtract),
    ('+' as u32, Key::NumpadAdd),
    ('=' as u32, Key::NumpadEqual),
];

impl Key {
    /// Converts an ASCII character to a key, if possible. This returns
    /// None if the character is unknown.
    ///
    /// Note that this can't distinguish between physical keys, i.e. '0'
    /// may be from the number row or the keypad, but it always maps
    /// to '.zero'.
    ///
    /// This is what we want, we want people to create keybindings that
    /// are independent of the physical key.
    pub fn from_ascii(ch: u8) -> Option<Key> {
        CODEPOINT_MAP
            .iter()
            // No ASCII characters should ever map to a keypad key
            .filter(|e| !e.1.keypad())
            .find(|e| e.0 == u32::from(ch))
            .map(|e| e.1)
    }

    /// Converts a W3C key code to a Ghostty key enum value.
    ///
    /// All required W3C key codes are supported, but there are a number of
    /// non-standard key codes that are not supported. In the case the value is
    /// invalid or unsupported, this function will return None.
    pub fn from_w3c(code: &str) -> Option<Key> {
        // If the code is bigger than our buffer it can't possibly match.
        if code.len() > 128 {
            return None;
        }

        // First just check the whole thing lowercased, this is the simple case
        if let Some(k) = Key::from_name(&code.to_ascii_lowercase()) {
            return Some(k);
        }

        // We need to convert FooBar to foo_bar
        let mut result = String::new();
        for (i, ch) in code.bytes().enumerate() {
            match ch {
                b'a'..=b'z' => result.push(ch as char),

                // Caps and numbers trigger underscores
                b'A'..=b'Z' | b'0'..=b'9' => {
                    if i > 0 {
                        result.push('_');
                    }
                    result.push(ch.to_ascii_lowercase() as char);
                }

                // We don't know of any key codes that aren't alphanumeric.
                _ => return None,
            }
        }

        Key::from_name(&result)
    }

    /// Converts a Ghostty key enum value to a W3C key code.
    pub fn w3c(self) -> String {
        let name = self.name();
        let mut out = String::with_capacity(name.len());
        let mut upper_next = true;
        for ch in name.chars() {
            if ch == '_' {
                upper_next = true;
            } else if upper_next {
                out.push(ch.to_ascii_uppercase());
                upper_next = false;
            } else {
                out.push(ch);
            }
        }
        out
    }

    /// True if this key represents a printable character.
    pub fn printable(self) -> bool {
        CODEPOINT_MAP.iter().any(|e| e.1 == self)
    }

    /// True if this key is a modifier.
    pub fn modifier(self) -> bool {
        matches!(
            self,
            Key::ShiftLeft
                | Key::ControlLeft
                | Key::AltLeft
                | Key::MetaLeft
                | Key::ShiftRight
                | Key::ControlRight
                | Key::AltRight
                | Key::MetaRight
        )
    }

    /// Whether this key should be remappable by the operating system.
    ///
    /// On certain OSes (namely Linux and the BSDs) certain keys like the
    /// functional keys are expected to be remappable by the user, such as
    /// in the very common use case of swapping the Caps Lock key with the
    /// Escape key with the XKB option `caps:swapescape`.
    ///
    /// However, the way XKB implements this is by essentially acting as a
    /// software key remapper that destroys all information about the original
    /// physical key, leading to very annoying bugs like #7309 where the
    /// physical key `XKB_KEY_c` gets remapped into `XKB_KEY_Cyrillic_tse`,
    /// which causes all of our physical key handling to completely break down.
    /// _Very naughty._
    ///
    /// As a compromise, given that writing system keys (§3.1.1) comprise the
    /// majority of keys that "change meaning [...] based on the current locale
    /// and keyboard layout", we allow all other keys to be remapped by default
    /// since they should be fairly harmless. We might consider making this
    /// configurable, but for now this should at least placate most people.
    pub fn should_be_remappable(self) -> bool {
        let v = self as i32;
        // "Writing System Keys" § 3.1.1 is the contiguous range
        // backquote ..= slash.
        !(Key::Backquote as i32..=Key::Slash as i32).contains(&v)
    }

    /// Returns true if this is a keypad key.
    pub fn keypad(self) -> bool {
        self.name().starts_with("numpad_")
    }

    /// Returns the codepoint representing this key, or None if the key is not
    /// printable.
    pub fn codepoint(self) -> Option<u32> {
        CODEPOINT_MAP.iter().find(|e| e.1 == self).map(|e| e.0)
    }

    /// true if this key is one of the left or right versions of super (MacOS)
    /// or ctrl.
    pub fn ctrl_or_super(self) -> bool {
        // Non-darwin target.
        self == Key::ControlLeft || self == Key::ControlRight
    }

    /// true if this key is either left or right shift.
    pub fn left_or_right_shift(self) -> bool {
        self == Key::ShiftLeft || self == Key::ShiftRight
    }

    /// true if this key is either left or right alt.
    pub fn left_or_right_alt(self) -> bool {
        self == Key::AltLeft || self == Key::AltRight
    }
}

/// This sets either "ctrl" or "super" to true (but not both)
/// on mods depending on if the build target is Mac or not. On
/// Mac, we default to super (i.e. super+c for copy) and on
/// non-Mac we default to ctrl (i.e. ctrl+c for copy).
pub fn ctrl_or_super(mods: Mods) -> Mods {
    let mut copy = mods;
    // Non-darwin target.
    copy.ctrl = true;
    copy
}

#[cfg(test)]
#[allow(clippy::unwrap_used)]
mod tests {
    use super::*;

    #[test]
    fn from_ascii_should_not_return_keypad_keys() {
        assert_eq!(Key::from_ascii(b'0'), Some(Key::Digit0));
        assert_eq!(Key::from_ascii(b'*'), None);
    }

    #[test]
    fn keypad_keys() {
        assert!(Key::Numpad0.keypad());
        assert!(!Key::Digit1.keypad());
    }

    #[test]
    fn w3c() {
        // All our keys should convert to and from the W3C format.
        for &key in Key::ALL {
            assert_eq!(Some(key), Key::from_w3c(&key.w3c()), "{key:?}");
        }
    }

    #[test]
    fn w3c_names() {
        assert_eq!(Key::KeyA.w3c(), "KeyA");
        assert_eq!(Key::ArrowUp.w3c(), "ArrowUp");
        assert_eq!(Key::Fn.w3c(), "Fn");
    }

    #[test]
    fn should_be_remappable_range() {
        assert!(!Key::KeyA.should_be_remappable());
        assert!(!Key::Slash.should_be_remappable());
        assert!(Key::AltLeft.should_be_remappable());
        assert!(Key::Unidentified.should_be_remappable());
    }

    #[test]
    fn ctrl_or_super_test() {
        let m = ctrl_or_super(Mods::default());
        assert!(m.ctrl_or_super());
    }
}