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use tracing::debug;
use super::{Cursor, Line, Position, ScreenBuffer};
/// `EscapeState` holds stateful information about the incoming
/// data to allow for proper processing of ansii escape codes/characters.
#[derive(Debug, PartialEq, Eq)]
pub(super) enum EscapeState {
/// Has not received ansii escape characters
Normal,
/// Just received an ESC (0x1B)
Esc,
/// Received ESC and then '[' (0x5B)
Csi,
}
/// Represents a section of an ascii escape sequence.
#[derive(Clone, Debug, PartialEq, Eq)]
pub(super) enum EscapePart {
/// The default state when not actively processing an escape sequence.
Empty,
/// Collects ascii digits (0-9) as they are received individually and are
/// eventually combined to create the final number that the `Action` will
/// perform on i.e. `vec!['2', '3']` -> `23`.
Numbers(Vec<char>),
/// The `Separator` represents the `;` used in ascii escape sequences.
Separator,
/// The `Action` represents the (typically) last letter of an escape
/// sequence that determines what action is to be taken i.e. `ESC[2J`.
Action(char),
}
impl Default for EscapePart {
fn default() -> Self {
Self::Empty
}
}
/// A state-holder/collection for building ascii escape sequences
/// from incoming data to enable proper processing/execution.
#[derive(Clone, Debug, PartialEq, Eq)]
pub(super) struct EscapeSequence {
sequence: Vec<EscapePart>,
part: EscapePart,
}
impl EscapeSequence {
pub(super) fn new() -> Self {
Self {
sequence: Vec::new(),
part: EscapePart::Empty,
}
}
/// Clear's the sequence and sets the part to [`EscapePart::Empty`].
pub(super) fn reset(&mut self) {
// Clear is probably good since it will continue to
// fill up to similar sizes throughout the program.
self.sequence.clear();
self.part = EscapePart::Empty;
}
/// Appends the `part` that is currently being processed to the `sequence`.
fn push_part(&mut self) {
self.sequence.push(std::mem::take(&mut self.part));
}
/// Appends a [`EscapePart::Separator`] to `Self.sequence`.
pub(super) fn insert_separator(&mut self) {
if self.part != EscapePart::Empty {
self.push_part();
}
self.sequence.push(EscapePart::Separator);
}
/// Adds numbers to the in-progress part of the escape sequence
pub(super) fn push_num(&mut self, num: char) {
match &mut self.part {
EscapePart::Numbers(nums) => nums.push(num),
_ => self.part = EscapePart::Numbers(vec![num]),
}
}
/// Pushes the action to the escape sequence, signaling the end
/// and results in carrying out the action for the escape sequence
/// and then resetting its values.
pub(super) fn push_action(&mut self, action: char) {
if self.part != EscapePart::Empty {
self.push_part();
}
self.sequence.push(EscapePart::Action(action));
}
}
impl ScreenBuffer {
pub(crate) fn parse_sequence(&mut self) {
let span = tracing::span!(tracing::Level::DEBUG, "Escape sequence");
let _enter = span.enter();
match &self.escape_sequence.sequence[..] {
[
EscapePart::Numbers(line_nums),
EscapePart::Separator,
EscapePart::Numbers(col_nums),
EscapePart::Action(action),
] => {
debug!("Got ESC[{:?};{:?}{}", line_nums, col_nums, action);
match action {
// Move cursor to (line_num, col_num)
'H' | 'f' => {
// Can unwrap because it is guaranteed elsewhere that
// `EscapePart::Numbers(Vec<Char>)` only holds ascii digits (0-9).
let line_num: u16 = line_nums.iter().collect::<String>().parse().unwrap();
let col_num: u16 = col_nums.iter().collect::<String>().parse().unwrap();
self.set_cursor_pos((col_num, line_num));
}
_ => {}
}
self.escape_state = EscapeState::Normal;
}
[
EscapePart::Separator,
EscapePart::Numbers(col_nums),
EscapePart::Action(action),
] => {
debug!("Got ESC[;{:?}{}", col_nums, action);
match action {
// Move cursor to (same, col_num)
'H' | 'f' => {
// Can unwrap because it is guaranteed elsewhere that
// `EscapePart::Numbers(Vec<Char>)` only holds ascii digits (0-9).
let col_num: u16 = col_nums.iter().collect::<String>().parse().unwrap();
self.cursor_pos.x = col_num;
}
_ => {}
}
self.escape_state = EscapeState::Normal;
}
[EscapePart::Numbers(nums), EscapePart::Action(action)] => {
debug!("Got ESC[{:?}{}", nums, action);
// Can unwrap because it is guaranteed elsewhere that
// `EscapePart::Numbers(Vec<Char>)` only holds ascii digits (0-9).
let num: u16 = nums.iter().collect::<String>().parse().unwrap();
// NOTE: These functions are solely doing what they say and do NOT move the cursor
match (num, action) {
// Move cursor up # of lines
(num, 'A') => self.move_cursor_up(num),
// Move cursor down # of lines
(num, 'B') => self.move_cursor_down(num),
// Move cursor right # of cols
(num, 'C') => self.move_cursor_right(num),
// Move cursor left # of cols
(num, 'D') => self.move_cursor_left(num),
// Moves cursor to beginning of line, # lines down
(num, 'E') => {
self.set_cursor_pos((0, (self.cursor_pos.y as u16) + num));
while self.cursor_pos.y > self.lines.len() {
self.lines.push_back(Line::new(self.width as usize));
}
}
// Moves cursor to beginning of line, # lines up
(num, 'F') => self.set_cursor_pos((0, (self.cursor_pos.y as u16) - num)),
// Moves cursor to column #
(num, 'G') => self.set_cursor_col(num),
// Erase from cursor until end of screen
(0, 'J') => self.clear_from_cursor_to_eos(),
// Erase from cursor to beginning of screen
(1, 'J') => self.clear_from_cursor_to_sos(),
// Erase entire screen
(2, 'J') => {
for _ in 0..=self.height {
self.lines.push_back(Line::new(self.width as usize));
}
self.view_start = self.lines.len() - self.height as usize;
}
// Erase from cursor to end of line
(0, 'K') => self.clear_from_cursor_to_eol(),
// Erase start of line to cursor
(1, 'K') => self.clear_from_cursor_to_sol(),
// Erase entire line
(2, 'K') => self.clear_whole_line(),
_ => {}
}
self.escape_state = EscapeState::Normal;
}
[EscapePart::Action(action)] => {
debug!("Got ESC[{}", action);
match action {
// Set cursor position to 0, 0
'H' => self.cursor_pos = Position::home(),
// Erase from cursor until end of screen
'J' => self.clear_from_cursor_to_eos(),
// Erase from cursor to end of line
'K' => self.clear_from_cursor_to_eol(),
'C' => self.move_cursor_right(1),
'D' => self.move_cursor_left(1),
action if action.is_alphabetic() => {}
_ => {}
}
self.escape_state = EscapeState::Normal;
}
_ => self.escape_state = EscapeState::Normal,
}
}
}