527 lines
16 KiB
Rust
527 lines
16 KiB
Rust
/*
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* Copyright (c) 2023 Marceline Cramer
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* Copyright (c) 2023 Emma Tebibyte <emma@tebibyte.media>
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*
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* This program is free software: you can redistribute it and/or modify it under
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* the terms of the GNU Affero General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see https://www.gnu.org/licenses/.
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*/
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use std::{
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env::args,
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ffi::OsString,
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fs::{ File, write },
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io::{
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Read,
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stdout,
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Stdout,
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Write,
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},
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os::fd::FromRawFd,
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path::{ Path }
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};
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use crossterm::{
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cursor,
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event::{read, Event, KeyCode, KeyEvent},
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terminal, ExecutableCommand, Result,
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};
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use ropey::Rope;
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use yacexits::{ exit, EX_DATAERR, EX_UNAVAILABLE };
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struct Buffer {
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pub text: Rope,
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}
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impl Buffer {
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pub fn from_str(text: &str) -> Self {
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Self {
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text: Rope::from_str(text),
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}
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}
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pub fn draw(
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&self,
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cols: u16,
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rows: u16,
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scroll: Cursor,
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out: &mut (impl ExecutableCommand + Write),
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) -> Result<u32> {
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let lr_width = self.text.len_lines().ilog10() + 1;
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let gutter_width = lr_width + 1;
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let text_width = cols as usize - gutter_width as usize;
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out.execute(cursor::MoveTo(0, 0))?;
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for (row, line) in (0..rows).zip(self.text.lines_at(scroll.line)) {
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// only the last line is empty and should be skipped
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if line.len_chars() == 0 {
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break;
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}
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let row = row as usize + scroll.line;
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write!(out, "{:width$} ", row, width = lr_width as usize)?;
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let lhs = scroll.column;
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let width = line.len_chars().saturating_sub(1); // lop off whitespace
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if lhs < width {
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let window = text_width.min(width - lhs);
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let rhs = lhs + window;
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write!(out, "{}", line.slice(lhs..rhs))?;
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}
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out.execute(cursor::MoveToNextLine(1))?;
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}
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Ok(gutter_width)
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}
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pub fn clamped_cursor(&self, cursor: Cursor) -> Cursor {
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Cursor {
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line: cursor.line,
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column: cursor
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.column
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.min(self.text.line(cursor.line).len_chars() - 1),
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}
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}
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pub fn cursor_to_char(&self, cursor: Cursor) -> usize {
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let cursor = self.clamped_cursor(cursor);
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self.text.line_to_char(cursor.line) + cursor.column
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}
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pub fn move_cursor(&self, cursor: &mut Cursor, direction: Direction, enable_linewrap: bool) {
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*cursor = self.clamped_cursor(*cursor);
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match direction {
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Direction::Left => {
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if cursor.column > 0 {
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cursor.column -= 1;
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} else if enable_linewrap && cursor.line > 0 {
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cursor.line -= 1;
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let line = self.text.line(cursor.line);
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cursor.column = line.len_chars() - 1;
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}
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}
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Direction::Down => {
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if cursor.line + 2 < self.text.len_lines() {
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cursor.line += 1;
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}
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}
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Direction::Up => {
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if cursor.line > 0 {
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cursor.line -= 1;
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}
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}
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Direction::Right => {
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let line = self.text.line(cursor.line);
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if cursor.column + 2 > line.len_chars() {
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if enable_linewrap && cursor.line + 2 < self.text.len_lines() {
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cursor.line += 1;
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cursor.column = 0;
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}
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} else {
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cursor.column += 1;
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}
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}
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}
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}
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}
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#[derive(Copy, Clone, Debug, Default)]
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struct Cursor {
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pub column: usize,
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pub line: usize,
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}
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#[derive(Clone, Debug, Default)]
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struct NormalState {
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pub error: Option<String>,
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}
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#[derive(Clone, Debug, Default)]
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struct CommandState {
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pub buf: String,
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pub cursor: usize,
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}
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#[derive(Copy, Clone, Debug)]
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struct InsertState {
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append: bool,
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}
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#[derive(Clone, Debug)]
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enum Mode {
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Normal(NormalState),
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Command(CommandState),
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Visual,
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Insert(InsertState),
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}
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impl Default for Mode {
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fn default() -> Self {
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Mode::Normal(Default::default())
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}
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}
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impl Mode {
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pub fn cursor_style(&self) -> cursor::SetCursorStyle {
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use cursor::SetCursorStyle as Style;
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match self {
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Mode::Normal(_) => Style::SteadyBlock,
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Mode::Visual => Style::BlinkingBlock,
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Mode::Insert(_) => Style::BlinkingBar,
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Mode::Command(_) => Style::SteadyUnderScore,
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}
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}
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}
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#[derive(Copy, Clone, Debug)]
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enum Direction {
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Left,
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Down,
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Up,
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Right,
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}
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struct State {
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pub buffer: Buffer,
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pub cursor: Cursor,
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pub file: Option<OsString>,
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pub mode: Mode,
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pub scroll: Cursor,
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pub size: (usize, usize),
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pub quit: bool,
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}
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impl State {
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pub fn from_str(file_name: Option<OsString>, text: &str) -> Result<Self> {
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let (cols, rows) = terminal::size()?;
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Ok(Self {
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buffer: Buffer::from_str(text),
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cursor: Cursor::default(),
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file: file_name,
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mode: Mode::default(),
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scroll: Cursor::default(),
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size: (cols as usize, rows as usize),
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quit: false,
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})
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}
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pub fn draw(&self, out: &mut impl Write) -> Result<()> {
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// begin update
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let (cols, rows) = terminal::size()?;
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out.execute(terminal::BeginSynchronizedUpdate)?;
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out.execute(terminal::Clear(terminal::ClearType::All))?;
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// draw status line
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let mut set_cursor_pos = None;
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let mut show_status_bar = false;
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match &self.mode {
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Mode::Command(CommandState { buf, cursor }) => {
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let col = *cursor as u16 + 1;
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let row = rows - 1;
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out.execute(cursor::MoveTo(0, row))?;
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write!(out, ":{}", buf)?;
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set_cursor_pos = Some((col, row));
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show_status_bar = true;
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}
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Mode::Normal(NormalState { error: Some(error) }) => {
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out.execute(cursor::MoveTo(0, rows - 1))?;
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write!(out, "{}", error)?;
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show_status_bar = true;
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}
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_ => {}
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}
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// draw buffer
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let buffer_rows = if show_status_bar { rows - 1 } else { rows };
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let lr_width = self.buffer.draw(cols, buffer_rows, self.scroll, out)?;
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// draw cursor
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let cursor_pos = set_cursor_pos.unwrap_or_else(|| {
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// calculate cursor position on buffer
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let cursor = self.buffer.clamped_cursor(self.cursor);
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let col = cursor.column.saturating_sub(self.scroll.column) as u16;
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let row = cursor.line.saturating_sub(self.scroll.line) as u16;
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let col = col + lr_width as u16;
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(col, row)
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});
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out.execute(cursor::MoveTo(cursor_pos.0, cursor_pos.1))?;
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out.execute(self.mode.cursor_style())?;
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// finish update
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out.execute(terminal::EndSynchronizedUpdate)?;
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Ok(())
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}
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pub fn on_event(&mut self, event: Event) {
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match &self.mode {
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Mode::Normal(state) => self.on_normal_event(event, state.clone()),
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Mode::Command(state) => self.on_command_event(event, state.clone()),
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Mode::Visual => self.on_visual_event(event),
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Mode::Insert(state) => self.on_insert_event(event, state.clone()),
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}
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}
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fn on_normal_event(&mut self, event: Event, mut state: NormalState) {
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// reset the error from the last event
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state.error = None;
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match event {
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Event::Key(KeyEvent { code, .. }) => match code {
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KeyCode::Char('i') => {
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let state = InsertState { append: false };
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self.mode = Mode::Insert(state);
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}
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KeyCode::Char('a') => {
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let state = InsertState { append: true };
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self.move_cursor(Direction::Right);
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self.mode = Mode::Insert(state);
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}
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KeyCode::Char(':') => {
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self.mode = Mode::Command(Default::default());
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}
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KeyCode::Char('v') => {
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self.mode = Mode::Visual;
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}
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code => self.on_any_key(code),
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},
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event => self.on_any_event(event),
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}
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match self.mode {
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Mode::Normal(_) => self.mode = Mode::Normal(state),
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_ => {}
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}
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}
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fn on_command_event(&mut self, event: Event, mut state: CommandState) {
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match event {
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Event::Key(KeyEvent { code, .. }) => match code {
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KeyCode::Char(c) => {
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state.buf.insert(state.cursor, c);
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state.cursor += 1;
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}
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KeyCode::Backspace => {
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if state.cursor > 0 {
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state.cursor -= 1;
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state.buf.remove(state.cursor);
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}
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}
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KeyCode::Delete if state.cursor < state.buf.len() => {
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state.buf.remove(state.cursor);
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}
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KeyCode::Left if state.cursor > 0 => {
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state.cursor -= 1;
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}
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KeyCode::Right if state.cursor < state.buf.len() => {
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state.cursor += 1;
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}
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KeyCode::Enter => {
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// TODO add to command history
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let result = self.execute_command(&state.buf);
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let error = result.err();
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self.mode = Mode::Normal(NormalState { error });
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return;
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}
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code => return self.on_any_key(code),
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},
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event => return self.on_any_event(event),
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}
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self.mode = Mode::Command(state);
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}
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fn on_visual_event(&mut self, event: Event) {
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match event {
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Event::Key(KeyEvent { code, .. }) => match code {
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KeyCode::Esc => {
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self.mode = Mode::default();
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}
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code => self.on_any_key(code),
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},
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event => self.on_any_event(event),
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}
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}
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fn on_insert_event(&mut self, event: Event, state: InsertState) {
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match event {
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Event::Key(KeyEvent { code, .. }) => match code {
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KeyCode::Char(c) => {
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let index = self.buffer.cursor_to_char(self.cursor);
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self.buffer.text.insert_char(index, c);
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self.move_cursor(Direction::Right)
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}
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KeyCode::Backspace => {
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self.move_cursor(Direction::Left);
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let index = self.buffer.cursor_to_char(self.cursor);
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self.buffer.text.remove(index..=index);
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}
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KeyCode::Delete => {
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let index = self.buffer.cursor_to_char(self.cursor);
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self.buffer.text.remove(index..=index);
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}
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KeyCode::Enter => {
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let index = self.buffer.cursor_to_char(self.cursor);
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self.buffer.text.insert_char(index, '\n');
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self.cursor.line += 1;
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self.cursor.column = 0;
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}
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KeyCode::Esc => {
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if state.append {
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self.move_cursor(Direction::Left);
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}
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self.mode = Mode::default();
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}
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code => self.on_any_key(code),
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},
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event => self.on_any_event(event),
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}
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}
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fn on_any_event(&mut self, event: Event) {
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match event {
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Event::Resize(cols, rows) => {
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self.size = (cols as usize, rows as usize);
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}
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Event::Key(KeyEvent { code, .. }) => self.on_any_key(code),
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_ => {}
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}
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}
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fn on_any_key(&mut self, code: KeyCode) {
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match code {
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KeyCode::Esc => self.mode = Mode::default(),
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KeyCode::Char('h') | KeyCode::Left => self.move_cursor(Direction::Left),
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KeyCode::Char('j') | KeyCode::Down => self.move_cursor(Direction::Down),
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KeyCode::Char('k') | KeyCode::Up => self.move_cursor(Direction::Up),
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KeyCode::Char('l') | KeyCode::Right => self.move_cursor(Direction::Right),
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_ => {}
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}
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}
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fn write_buffer(&mut self, file: OsString) -> std::result::Result<(), String> {
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let out = self.buffer.text.bytes().collect::<Vec<u8>>();
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let handle = file
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.clone()
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.into_string()
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.map_err(|err| {
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format!("{:?}", err)
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})?;
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write(handle, out.as_slice())
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.map_err(|err| {
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format!("{:?}", err)
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})?;
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Ok(())
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}
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fn execute_command(&mut self, command: &str) -> std::result::Result<(), String> {
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match command {
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"q" => self.quit = true,
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"w" => {
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let handle = self.file.clone().unwrap_or_else(|| {
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OsString::from("file")
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});
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self.write_buffer(handle)?;
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},
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command => {
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return Err(
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format!("{:?}: Unrecognized command.", command)
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);
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},
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}
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Ok(())
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}
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fn move_cursor(&mut self, direction: Direction) {
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self.buffer.move_cursor(&mut self.cursor, direction, true);
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if self.cursor.column < self.scroll.column + 3 {
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self.scroll.column = self.cursor.column.saturating_sub(3);
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} else if self.cursor.column + 6 >= self.scroll.column + self.size.0 {
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self.scroll.column = self.cursor.column.saturating_sub(self.size.0 - 6);
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}
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if self.cursor.line < self.scroll.line {
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self.scroll.line = self.cursor.line;
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} else if self.cursor.line + 3 >= self.scroll.line + self.size.1 {
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self.scroll.line = self.cursor.line + 3 - self.size.1;
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}
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}
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}
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fn screen_main(stdout: &mut Stdout, mut state: State) -> Result<()> {
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while !state.quit {
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state.draw(stdout)?;
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let event = read()?;
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state.on_event(event);
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}
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Ok(())
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}
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fn main() -> Result<()> {
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let argv = args().collect::<Vec<String>>();
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let mut buf = Vec::new();
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let file_name: Option<OsString>;
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match argv.get(1).map(|s| s.as_str()) {
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Some("-") | None => {
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file_name = None;
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let stdin = 0; // get stdin as a file descriptor
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if unsafe { libc::isatty(stdin) } == 0 {
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unsafe { File::from_raw_fd(stdin) }
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} else { File::open("/dev/null").unwrap() }
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},
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Some(path) => {
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let input_file = Path::new(path);
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file_name = input_file.clone().file_name().map(|f| f.to_owned());
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File::open(input_file).unwrap_or_else(|_| {
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let mut err = String::new();
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if !input_file.exists() {
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err = "No such file or directory.".to_string();
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} else if input_file.is_dir() {
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err = "Is a directory.".to_string();
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}
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eprintln!("{}: {}: {}", argv[0], path, err);
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exit(EX_UNAVAILABLE);
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})
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},
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}.read_to_end(&mut buf).unwrap();
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let text = String::from_utf8(buf).unwrap_or_else(|_| {
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eprintln!(
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"{}: {}: File contents are not valid UTF-8.", argv[0], argv[1]
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);
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exit(EX_DATAERR);
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});
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let state = State::from_str(file_name, &text)?;
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let mut stdout = stdout();
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terminal::enable_raw_mode()?;
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stdout.execute(terminal::EnterAlternateScreen)?;
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let result = screen_main(&mut stdout, state);
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stdout.execute(terminal::LeaveAlternateScreen)?;
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terminal::disable_raw_mode()?;
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result
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}
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