minicrossterm/src/event/sys/windows/parse.rs

376 lines
15 KiB
Rust

use crossterm_winapi::{ControlKeyState, EventFlags, KeyEventRecord, ScreenBuffer};
use winapi::um::{
wincon::{
CAPSLOCK_ON, LEFT_ALT_PRESSED, LEFT_CTRL_PRESSED, RIGHT_ALT_PRESSED, RIGHT_CTRL_PRESSED,
SHIFT_PRESSED,
},
winuser::{
GetForegroundWindow, GetKeyboardLayout, GetWindowThreadProcessId, ToUnicodeEx, VK_BACK,
VK_CONTROL, VK_DELETE, VK_DOWN, VK_END, VK_ESCAPE, VK_F1, VK_F24, VK_HOME, VK_INSERT,
VK_LEFT, VK_MENU, VK_NEXT, VK_NUMPAD0, VK_NUMPAD9, VK_PRIOR, VK_RETURN, VK_RIGHT, VK_SHIFT,
VK_TAB, VK_UP,
},
};
use crate::{
event::{
Event, KeyCode, KeyEvent, KeyEventKind, KeyModifiers, MouseButton, MouseEvent,
MouseEventKind,
},
Result,
};
#[derive(Default)]
pub struct MouseButtonsPressed {
pub(crate) left: bool,
pub(crate) right: bool,
pub(crate) middle: bool,
}
pub(crate) fn handle_mouse_event(
mouse_event: crossterm_winapi::MouseEvent,
buttons_pressed: &MouseButtonsPressed,
) -> Option<Event> {
if let Ok(Some(event)) = parse_mouse_event_record(&mouse_event, buttons_pressed) {
return Some(Event::Mouse(event));
}
None
}
enum WindowsKeyEvent {
KeyEvent(KeyEvent),
Surrogate(u16),
}
pub(crate) fn handle_key_event(
key_event: KeyEventRecord,
surrogate_buffer: &mut Option<u16>,
) -> Option<Event> {
let windows_key_event = parse_key_event_record(&key_event)?;
match windows_key_event {
WindowsKeyEvent::KeyEvent(key_event) => {
// Discard any buffered surrogate value if another valid key event comes before the
// next surrogate value.
*surrogate_buffer = None;
Some(Event::Key(key_event))
}
WindowsKeyEvent::Surrogate(new_surrogate) => {
let ch = handle_surrogate(surrogate_buffer, new_surrogate)?;
let modifiers = KeyModifiers::from(&key_event.control_key_state);
let key_event = KeyEvent::new(KeyCode::Char(ch), modifiers);
Some(Event::Key(key_event))
}
}
}
fn handle_surrogate(surrogate_buffer: &mut Option<u16>, new_surrogate: u16) -> Option<char> {
match *surrogate_buffer {
Some(buffered_surrogate) => {
*surrogate_buffer = None;
std::char::decode_utf16([buffered_surrogate, new_surrogate])
.next()
.unwrap()
.ok()
}
None => {
*surrogate_buffer = Some(new_surrogate);
None
}
}
}
impl From<&ControlKeyState> for KeyModifiers {
fn from(state: &ControlKeyState) -> Self {
let shift = state.has_state(SHIFT_PRESSED);
let alt = state.has_state(LEFT_ALT_PRESSED | RIGHT_ALT_PRESSED);
let control = state.has_state(LEFT_CTRL_PRESSED | RIGHT_CTRL_PRESSED);
let mut modifier = KeyModifiers::empty();
if shift {
modifier |= KeyModifiers::SHIFT;
}
if control {
modifier |= KeyModifiers::CONTROL;
}
if alt {
modifier |= KeyModifiers::ALT;
}
modifier
}
}
enum CharCase {
LowerCase,
UpperCase,
}
fn try_ensure_char_case(ch: char, desired_case: CharCase) -> char {
match desired_case {
CharCase::LowerCase if ch.is_uppercase() => {
let mut iter = ch.to_lowercase();
// Unwrap is safe; iterator yields one or more chars.
let ch_lower = iter.next().unwrap();
if iter.next().is_none() {
ch_lower
} else {
ch
}
}
CharCase::UpperCase if ch.is_lowercase() => {
let mut iter = ch.to_uppercase();
// Unwrap is safe; iterator yields one or more chars.
let ch_upper = iter.next().unwrap();
if iter.next().is_none() {
ch_upper
} else {
ch
}
}
_ => ch,
}
}
// Attempts to return the character for a key event accounting for the user's keyboard layout.
// The returned character (if any) is capitalized (if applicable) based on shift and capslock state.
// Returns None if the key doesn't map to a character or if it is a dead key.
// We use the *currently* active keyboard layout (if it can be determined). This layout may not
// correspond to the keyboard layout that was active when the user typed their input, since console
// applications get their input asynchronously from the terminal. By the time a console application
// can process a key input, the user may have changed the active layout. In this case, the character
// returned might not correspond to what the user expects, but there is no way for a console
// application to know what the keyboard layout actually was for a key event, so this is our best
// effort. If a console application processes input in a timely fashion, then it is unlikely that a
// user has time to change their keyboard layout before a key event is processed.
fn get_char_for_key(key_event: &KeyEventRecord) -> Option<char> {
let virtual_key_code = key_event.virtual_key_code as u32;
let virtual_scan_code = key_event.virtual_scan_code as u32;
let key_state = [0u8; 256];
let mut utf16_buf = [0u16, 16];
let dont_change_kernel_keyboard_state = 0x4;
// Best-effort attempt at determining the currently active keyboard layout.
// At the time of writing, this works for a console application running in Windows Terminal, but
// doesn't work under a Conhost terminal. For Conhost, the window handle returned by
// GetForegroundWindow() does not appear to actually be the foreground window which has the
// keyboard layout associated with it (or perhaps it is, but also has special protection that
// doesn't allow us to query it).
// When this determination fails, the returned keyboard layout handle will be null, which is an
// acceptable input for ToUnicodeEx, as that argument is optional. In this case ToUnicodeEx
// appears to use the keyboard layout associated with the current thread, which will be the
// layout that was inherited when the console application started (or possibly when the current
// thread was spawned). This is then unfortunately not updated when the user changes their
// keyboard layout in the terminal, but it's what we get.
let active_keyboard_layout = unsafe {
let foreground_window = GetForegroundWindow();
let foreground_thread = GetWindowThreadProcessId(foreground_window, std::ptr::null_mut());
GetKeyboardLayout(foreground_thread)
};
let ret = unsafe {
ToUnicodeEx(
virtual_key_code,
virtual_scan_code,
key_state.as_ptr(),
utf16_buf.as_mut_ptr(),
utf16_buf.len() as i32,
dont_change_kernel_keyboard_state,
active_keyboard_layout,
)
};
// -1 indicates a dead key.
// 0 indicates no character for this key.
if ret < 1 {
return None;
}
let mut ch_iter = std::char::decode_utf16(utf16_buf.into_iter().take(ret as usize));
let mut ch = ch_iter.next()?.ok()?;
if ch_iter.next().is_some() {
// Key doesn't map to a single char.
return None;
}
let is_shift_pressed = key_event.control_key_state.has_state(SHIFT_PRESSED);
let is_capslock_on = key_event.control_key_state.has_state(CAPSLOCK_ON);
let desired_case = if is_shift_pressed ^ is_capslock_on {
CharCase::UpperCase
} else {
CharCase::LowerCase
};
ch = try_ensure_char_case(ch, desired_case);
Some(ch)
}
fn parse_key_event_record(key_event: &KeyEventRecord) -> Option<WindowsKeyEvent> {
let modifiers = KeyModifiers::from(&key_event.control_key_state);
let virtual_key_code = key_event.virtual_key_code as i32;
// We normally ignore all key release events, but we will make an exception for an Alt key
// release if it carries a u_char value, as this indicates an Alt code.
let is_alt_code = virtual_key_code == VK_MENU && !key_event.key_down && key_event.u_char != 0;
if is_alt_code {
let utf16 = key_event.u_char;
match utf16 {
surrogate @ 0xD800..=0xDFFF => {
return Some(WindowsKeyEvent::Surrogate(surrogate));
}
unicode_scalar_value => {
// Unwrap is safe: We tested for surrogate values above and those are the only
// u16 values that are invalid when directly interpreted as unicode scalar
// values.
let ch = std::char::from_u32(unicode_scalar_value as u32).unwrap();
let key_code = KeyCode::Char(ch);
let kind = if key_event.key_down {
KeyEventKind::Press
} else {
KeyEventKind::Release
};
let key_event = KeyEvent::new_with_kind(key_code, modifiers, kind);
return Some(WindowsKeyEvent::KeyEvent(key_event));
}
}
}
// Don't generate events for numpad key presses when they're producing Alt codes.
let is_numpad_numeric_key = (VK_NUMPAD0..=VK_NUMPAD9).contains(&virtual_key_code);
let is_only_alt_modifier = modifiers.contains(KeyModifiers::ALT)
&& !modifiers.contains(KeyModifiers::SHIFT | KeyModifiers::CONTROL);
if is_only_alt_modifier && is_numpad_numeric_key {
return None;
}
let parse_result = match virtual_key_code {
VK_SHIFT | VK_CONTROL | VK_MENU => None,
VK_BACK => Some(KeyCode::Backspace),
VK_ESCAPE => Some(KeyCode::Esc),
VK_RETURN => Some(KeyCode::Enter),
VK_F1..=VK_F24 => Some(KeyCode::F((key_event.virtual_key_code - 111) as u8)),
VK_LEFT => Some(KeyCode::Left),
VK_UP => Some(KeyCode::Up),
VK_RIGHT => Some(KeyCode::Right),
VK_DOWN => Some(KeyCode::Down),
VK_PRIOR => Some(KeyCode::PageUp),
VK_NEXT => Some(KeyCode::PageDown),
VK_HOME => Some(KeyCode::Home),
VK_END => Some(KeyCode::End),
VK_DELETE => Some(KeyCode::Delete),
VK_INSERT => Some(KeyCode::Insert),
VK_TAB if modifiers.contains(KeyModifiers::SHIFT) => Some(KeyCode::BackTab),
VK_TAB => Some(KeyCode::Tab),
_ => {
let utf16 = key_event.u_char;
match utf16 {
0x00..=0x1f => {
// Some key combinations generate either no u_char value or generate control
// codes. To deliver back a KeyCode::Char(...) event we want to know which
// character the key normally maps to on the user's keyboard layout.
// The keys that intentionally generate control codes (ESC, ENTER, TAB, etc.)
// are handled by their virtual key codes above.
get_char_for_key(key_event).map(KeyCode::Char)
}
surrogate @ 0xD800..=0xDFFF => {
return Some(WindowsKeyEvent::Surrogate(surrogate));
}
unicode_scalar_value => {
// Unwrap is safe: We tested for surrogate values above and those are the only
// u16 values that are invalid when directly interpreted as unicode scalar
// values.
let ch = std::char::from_u32(unicode_scalar_value as u32).unwrap();
Some(KeyCode::Char(ch))
}
}
}
};
if let Some(key_code) = parse_result {
let kind = if key_event.key_down {
KeyEventKind::Press
} else {
KeyEventKind::Release
};
let key_event = KeyEvent::new_with_kind(key_code, modifiers, kind);
return Some(WindowsKeyEvent::KeyEvent(key_event));
}
None
}
// The 'y' position of a mouse event or resize event is not relative to the window but absolute to screen buffer.
// This means that when the mouse cursor is at the top left it will be x: 0, y: 2295 (e.g. y = number of cells conting from the absolute buffer height) instead of relative x: 0, y: 0 to the window.
pub fn parse_relative_y(y: i16) -> Result<i16> {
let window_size = ScreenBuffer::current()?.info()?.terminal_window();
Ok(y - window_size.top)
}
fn parse_mouse_event_record(
event: &crossterm_winapi::MouseEvent,
buttons_pressed: &MouseButtonsPressed,
) -> Result<Option<MouseEvent>> {
let modifiers = KeyModifiers::from(&event.control_key_state);
let xpos = event.mouse_position.x as u16;
let ypos = parse_relative_y(event.mouse_position.y)? as u16;
let button_state = event.button_state;
let kind = match event.event_flags {
EventFlags::PressOrRelease => {
if button_state.left_button() && !buttons_pressed.left {
Some(MouseEventKind::Down(MouseButton::Left))
} else if !button_state.left_button() && buttons_pressed.left {
Some(MouseEventKind::Up(MouseButton::Left))
} else if button_state.right_button() && !buttons_pressed.right {
Some(MouseEventKind::Down(MouseButton::Right))
} else if !button_state.right_button() && buttons_pressed.right {
Some(MouseEventKind::Up(MouseButton::Right))
} else if button_state.middle_button() && !buttons_pressed.middle {
Some(MouseEventKind::Down(MouseButton::Middle))
} else if !button_state.middle_button() && buttons_pressed.middle {
Some(MouseEventKind::Up(MouseButton::Middle))
} else {
None
}
}
EventFlags::MouseMoved => {
let button = if button_state.right_button() {
MouseButton::Right
} else if button_state.middle_button() {
MouseButton::Middle
} else {
MouseButton::Left
};
if button_state.release_button() {
Some(MouseEventKind::Moved)
} else {
Some(MouseEventKind::Drag(button))
}
}
EventFlags::MouseWheeled => {
// Vertical scroll
// from https://docs.microsoft.com/en-us/windows/console/mouse-event-record-str
// if `button_state` is negative then the wheel was rotated backward, toward the user.
if button_state.scroll_down() {
Some(MouseEventKind::ScrollDown)
} else if button_state.scroll_up() {
Some(MouseEventKind::ScrollUp)
} else {
None
}
}
EventFlags::DoubleClick => None, // double click not supported by unix terminals
EventFlags::MouseHwheeled => None, // horizontal scroll not supported by unix terminals
_ => None,
};
Ok(kind.map(|kind| MouseEvent {
kind,
column: xpos,
row: ypos,
modifiers,
}))
}