nite/crates/ming/src/keymap/matcher.rs
2024-05-13 22:41:30 +03:00

102 lines
3.4 KiB
Rust

use crate::{KeyBinding, KeyContext, Keymap, KeymapVersion, Keystroke};
use smallvec::SmallVec;
use std::{cell::RefCell, rc::Rc};
pub(crate) struct KeystrokeMatcher {
pending_keystrokes: Vec<Keystroke>,
keymap: Rc<RefCell<Keymap>>,
keymap_version: KeymapVersion,
}
pub struct KeymatchResult {
pub bindings: SmallVec<[KeyBinding; 1]>,
pub pending: bool,
}
impl KeystrokeMatcher {
pub fn new(keymap: Rc<RefCell<Keymap>>) -> Self {
let keymap_version = keymap.borrow().version();
Self {
pending_keystrokes: Vec::new(),
keymap_version,
keymap,
}
}
pub fn has_pending_keystrokes(&self) -> bool {
!self.pending_keystrokes.is_empty()
}
/// Pushes a keystroke onto the matcher.
/// The result of the new keystroke is returned:
/// - KeyMatch::None =>
/// No match is valid for this key given any pending keystrokes.
/// - KeyMatch::Pending =>
/// There exist bindings which are still waiting for more keys.
/// - KeyMatch::Complete(matches) =>
/// One or more bindings have received the necessary key presses.
/// Bindings added later will take precedence over earlier bindings.
pub(crate) fn match_keystroke(
&mut self,
keystroke: &Keystroke,
context_stack: &[KeyContext],
) -> KeymatchResult {
let keymap = self.keymap.borrow();
// Clear pending keystrokes if the keymap has changed since the last matched keystroke.
if keymap.version() != self.keymap_version {
self.keymap_version = keymap.version();
self.pending_keystrokes.clear();
}
let mut pending_key = None;
let mut bindings = SmallVec::new();
for binding in keymap.bindings().rev() {
if !keymap.binding_enabled(binding, context_stack) {
continue;
}
for candidate in keystroke.match_candidates() {
self.pending_keystrokes.push(candidate.clone());
match binding.match_keystrokes(&self.pending_keystrokes) {
KeyMatch::Matched => {
bindings.push(binding.clone());
}
KeyMatch::Pending => {
pending_key.get_or_insert(candidate);
}
KeyMatch::None => {}
}
self.pending_keystrokes.pop();
}
}
if bindings.is_empty() && pending_key.is_none() && !self.pending_keystrokes.is_empty() {
drop(keymap);
self.pending_keystrokes.remove(0);
return self.match_keystroke(keystroke, context_stack);
}
let pending = if let Some(pending_key) = pending_key {
self.pending_keystrokes.push(pending_key);
true
} else {
self.pending_keystrokes.clear();
false
};
KeymatchResult { bindings, pending }
}
}
/// The result of matching a keystroke against a given keybinding.
/// - KeyMatch::None => No match is valid for this key given any pending keystrokes.
/// - KeyMatch::Pending => There exist bindings that is still waiting for more keys.
/// - KeyMatch::Some(matches) => One or more bindings have received the necessary key presses.
#[derive(Debug, PartialEq)]
pub enum KeyMatch {
None,
Pending,
Matched,
}