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alacritty/alacritty_terminal/src/grid/mod.rs

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// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! A specialized 2d grid implementation optimized for use in a terminal.
use std::cmp::{max, min, Ordering};
use std::ops::{Deref, Index, IndexMut, Range, RangeFrom, RangeFull, RangeInclusive, RangeTo};
use crate::index::{self, Column, IndexRange, Line, Point};
use crate::selection::Selection;
mod row;
pub use self::row::Row;
#[cfg(test)]
mod tests;
mod storage;
use self::storage::Storage;
const MIN_INIT_SIZE: usize = 1_000;
/// Bidirection iterator
pub trait BidirectionalIterator: Iterator {
fn prev(&mut self) -> Option<Self::Item>;
}
/// An item in the grid along with its Line and Column.
pub struct Indexed<T> {
pub inner: T,
pub line: Line,
pub column: Column,
}
impl<T> Deref for Indexed<T> {
type Target = T;
#[inline]
fn deref(&self) -> &T {
&self.inner
}
}
impl<T: PartialEq> ::std::cmp::PartialEq for Grid<T> {
fn eq(&self, other: &Self) -> bool {
// Compare struct fields and check result of grid comparison
self.raw.eq(&other.raw)
&& self.cols.eq(&other.cols)
&& self.lines.eq(&other.lines)
&& self.display_offset.eq(&other.display_offset)
&& self.scroll_limit.eq(&other.scroll_limit)
&& self.selection.eq(&other.selection)
&& self.url_highlight.eq(&other.url_highlight)
}
}
pub trait GridCell {
fn is_empty(&self) -> bool;
fn is_wrap(&self) -> bool;
fn set_wrap(&mut self, wrap: bool);
}
/// Represents the terminal display contents
#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct Grid<T> {
/// Lines in the grid. Each row holds a list of cells corresponding to the
/// columns in that row.
raw: Storage<T>,
/// Number of columns
cols: index::Column,
/// Number of lines.
///
/// Invariant: lines is equivalent to raw.len()
lines: index::Line,
/// Offset of displayed area
///
/// If the displayed region isn't at the bottom of the screen, it stays
/// stationary while more text is emitted. The scrolling implementation
/// updates this offset accordingly.
#[serde(default)]
display_offset: usize,
/// An limit on how far back it's possible to scroll
#[serde(default)]
scroll_limit: usize,
/// Selected region
#[serde(skip)]
pub selection: Option<Selection>,
#[serde(default)]
max_scroll_limit: usize,
/// Range for URL hover highlights
#[serde(default)]
pub url_highlight: Option<RangeInclusive<index::Linear>>,
}
#[derive(Copy, Clone)]
pub enum Scroll {
Lines(isize),
PageUp,
PageDown,
Top,
Bottom,
}
#[derive(Copy, Clone)]
pub enum ViewportPosition {
Visible(Line),
Above,
Below,
}
impl<T: GridCell + Copy + Clone> Grid<T> {
pub fn new(lines: index::Line, cols: index::Column, scrollback: usize, template: T) -> Grid<T> {
let raw = Storage::with_capacity(lines, Row::new(cols, &template));
Grid {
raw,
cols,
lines,
display_offset: 0,
scroll_limit: 0,
selection: None,
max_scroll_limit: scrollback,
url_highlight: None,
}
}
pub fn visible_to_buffer(&self, point: Point) -> Point<usize> {
Point { line: self.visible_line_to_buffer(point.line), col: point.col }
}
pub fn buffer_line_to_visible(&self, line: usize) -> ViewportPosition {
let offset = line.saturating_sub(self.display_offset);
if line < self.display_offset {
ViewportPosition::Below
} else if offset >= *self.num_lines() {
ViewportPosition::Above
} else {
ViewportPosition::Visible(self.lines - offset - 1)
}
}
pub fn visible_line_to_buffer(&self, line: Line) -> usize {
self.line_to_offset(line) + self.display_offset
}
/// Update the size of the scrollback history
pub fn update_history(&mut self, history_size: usize, template: &T) {
self.raw.update_history(history_size, Row::new(self.cols, &template));
self.max_scroll_limit = history_size;
self.scroll_limit = min(self.scroll_limit, history_size);
self.display_offset = min(self.display_offset, self.scroll_limit);
}
pub fn scroll_display(&mut self, scroll: Scroll) {
match scroll {
Scroll::Lines(count) => {
self.display_offset = min(
max((self.display_offset as isize) + count, 0isize) as usize,
self.scroll_limit,
);
},
Scroll::PageUp => {
self.display_offset = min(self.display_offset + self.lines.0, self.scroll_limit);
},
Scroll::PageDown => {
self.display_offset -= min(self.display_offset, self.lines.0);
},
Scroll::Top => self.display_offset = self.scroll_limit,
Scroll::Bottom => self.display_offset = 0,
}
}
pub fn resize(
&mut self,
lines: index::Line,
cols: index::Column,
cursor_pos: &mut Point,
template: &T,
) {
// Check that there's actually work to do and return early if not
if lines == self.lines && cols == self.cols {
return;
}
match self.lines.cmp(&lines) {
Ordering::Less => self.grow_lines(lines, template),
Ordering::Greater => self.shrink_lines(lines),
Ordering::Equal => (),
}
match self.cols.cmp(&cols) {
Ordering::Less => self.grow_cols(cols, cursor_pos, template),
Ordering::Greater => self.shrink_cols(cols, template),
Ordering::Equal => (),
}
}
fn increase_scroll_limit(&mut self, count: usize, template: &T) {
self.scroll_limit = min(self.scroll_limit + count, self.max_scroll_limit);
// Initialize new lines when the history buffer is smaller than the scroll limit
let history_size = self.raw.len().saturating_sub(*self.lines);
if history_size < self.scroll_limit {
let new = min(
max(self.scroll_limit - history_size, MIN_INIT_SIZE),
self.max_scroll_limit - history_size,
);
self.raw.initialize(new, Row::new(self.cols, template));
}
}
fn decrease_scroll_limit(&mut self, count: usize) {
self.scroll_limit = self.scroll_limit.saturating_sub(count);
}
/// Add lines to the visible area
///
/// Alacritty keeps the cursor at the bottom of the terminal as long as there
/// is scrollback available. Once scrollback is exhausted, new lines are
/// simply added to the bottom of the screen.
fn grow_lines(&mut self, new_line_count: index::Line, template: &T) {
let lines_added = new_line_count - self.lines;
// Need to "resize" before updating buffer
self.raw.grow_visible_lines(new_line_count, Row::new(self.cols, template));
self.lines = new_line_count;
// Move existing lines up if there is no scrollback to fill new lines
if lines_added.0 > self.scroll_limit {
let scroll_lines = lines_added - self.scroll_limit;
self.scroll_up(&(Line(0)..new_line_count), scroll_lines, template);
}
self.scroll_limit = self.scroll_limit.saturating_sub(*lines_added);
self.display_offset = self.display_offset.saturating_sub(*lines_added);
}
fn grow_cols(&mut self, cols: index::Column, cursor_pos: &mut Point, template: &T) {
// Truncate all buffered lines
self.raw.grow_hidden(cols, template);
let max_lines = self.lines.0 + self.max_scroll_limit;
// Iterate backwards with indices for mutation during iteration
let mut i = self.raw.len();
while i > 0 {
i -= 1;
// Grow the current line if there's wrapped content available
while i >= 1
&& self.raw[i].len() < cols.0
&& self.raw[i].last().map(GridCell::is_wrap) == Some(true)
{
// Remove wrap flag before appending additional cells
if let Some(cell) = self.raw[i].last_mut() {
cell.set_wrap(false);
}
// Append as many cells from the next line as possible
let len = min(self.raw[i - 1].len(), cols.0 - self.raw[i].len());
let mut cells = self.raw[i - 1].front_split_off(len);
self.raw[i].append(&mut cells);
if self.raw[i - 1].is_empty() {
// Remove following line if all cells have been drained
self.raw.remove(i - 1);
if self.raw.len() < self.lines.0 || self.scroll_limit == 0 {
// Add new line and move lines up if we can't pull from history
self.raw.insert(0, Row::new(cols, template), max_lines);
cursor_pos.line = Line(cursor_pos.line.saturating_sub(1));
} else {
// Make sure viewport doesn't move if line is outside of the visible area
if i < self.display_offset {
self.display_offset = self.display_offset.saturating_sub(1);
}
// Remove one line from scrollback, since we just moved it to the viewport
self.scroll_limit = self.scroll_limit.saturating_sub(1);
self.display_offset = min(self.display_offset, self.scroll_limit);
i -= 1;
}
} else if let Some(cell) = self.raw[i].last_mut() {
// Set wrap flag if next line still has cells
cell.set_wrap(true);
}
}
// Fill remaining cells
if self.raw[i].len() < cols.0 {
self.raw[i].grow(cols, template);
}
}
self.cols = cols;
}
fn shrink_cols(&mut self, cols: index::Column, template: &T) {
// Truncate all buffered lines
self.raw.shrink_hidden(cols);
let max_lines = self.lines.0 + self.max_scroll_limit;
// Iterate backwards with indices for mutation during iteration
let mut i = self.raw.len();
while i > 0 {
i -= 1;
if let Some(mut new_row) = self.raw[i].shrink(cols) {
// Set line as wrapped if cells got removed
if let Some(cell) = self.raw[i].last_mut() {
cell.set_wrap(true);
}
if Some(true) == new_row.last().map(|c| c.is_wrap() && i >= 1)
&& new_row.len() < cols.0
{
// Make sure previous wrap flag doesn't linger around
if let Some(cell) = new_row.last_mut() {
cell.set_wrap(false);
}
// Add removed cells to start of next row
self.raw[i - 1].append_front(new_row);
} else {
// Make sure viewport doesn't move if line is outside of the visible area
if i < self.display_offset {
self.display_offset = min(self.display_offset + 1, self.max_scroll_limit);
}
// Make sure new row is at least as long as new width
let occ = new_row.len();
if occ < cols.0 {
new_row.append(&mut vec![*template; cols.0 - occ]);
}
let row = Row::from_vec(new_row, occ);
// Add new row with all removed cells
self.raw.insert(i, row, max_lines);
// Increase scrollback history
self.scroll_limit = min(self.scroll_limit + 1, self.max_scroll_limit);
// Since inserted might exceed cols, we need to check the same line again
i += 1;
}
}
}
self.cols = cols;
}
/// Remove lines from the visible area
///
/// The behavior in Terminal.app and iTerm.app is to keep the cursor at the
/// bottom of the screen. This is achieved by pushing history "out the top"
/// of the terminal window.
///
/// Alacritty takes the same approach.
fn shrink_lines(&mut self, target: index::Line) {
let prev = self.lines;
self.selection = None;
self.url_highlight = None;
self.raw.rotate(*prev as isize - *target as isize);
self.raw.shrink_visible_lines(target);
self.lines = target;
}
/// Convert a Line index (active region) to a buffer offset
///
/// # Panics
///
/// This method will panic if `Line` is larger than the grid dimensions
pub fn line_to_offset(&self, line: index::Line) -> usize {
assert!(line < self.num_lines());
*(self.num_lines() - line - 1)
}
#[inline]
pub fn scroll_down(
&mut self,
region: &Range<index::Line>,
positions: index::Line,
template: &T,
) {
// Whether or not there is a scrolling region active, as long as it
// starts at the top, we can do a full rotation which just involves
// changing the start index.
//
// To accomodate scroll regions, rows are reordered at the end.
if region.start == Line(0) {
// Rotate the entire line buffer. If there's a scrolling region
// active, the bottom lines are restored in the next step.
self.raw.rotate_up(*positions);
if let Some(ref mut selection) = self.selection {
selection.rotate(-(*positions as isize));
}
self.url_highlight = None;
self.decrease_scroll_limit(*positions);
// Now, restore any scroll region lines
let lines = self.lines;
for i in IndexRange(region.end..lines) {
self.raw.swap_lines(i, i + positions);
}
// Finally, reset recycled lines
for i in IndexRange(Line(0)..positions) {
self.raw[i].reset(&template);
}
} else {
// Subregion rotation
for line in IndexRange((region.start + positions)..region.end).rev() {
self.raw.swap_lines(line, line - positions);
}
for line in IndexRange(region.start..(region.start + positions)) {
self.raw[line].reset(&template);
}
}
}
/// scroll_up moves lines at the bottom towards the top
///
/// This is the performance-sensitive part of scrolling.
pub fn scroll_up(&mut self, region: &Range<index::Line>, positions: index::Line, template: &T) {
if region.start == Line(0) {
// Update display offset when not pinned to active area
if self.display_offset != 0 {
self.display_offset =
min(self.display_offset + *positions, self.len() - self.num_lines().0);
}
self.increase_scroll_limit(*positions, template);
// Rotate the entire line buffer. If there's a scrolling region
// active, the bottom lines are restored in the next step.
self.raw.rotate(-(*positions as isize));
if let Some(ref mut selection) = self.selection {
selection.rotate(*positions as isize);
}
self.url_highlight = None;
// // This next loop swaps "fixed" lines outside of a scroll region
// // back into place after the rotation. The work is done in buffer-
// // space rather than terminal-space to avoid redundant
// // transformations.
let fixed_lines = *self.num_lines() - *region.end;
for i in 0..fixed_lines {
self.raw.swap(i, i + *positions);
}
// Finally, reset recycled lines
//
// Recycled lines are just above the end of the scrolling region.
for i in 0..*positions {
self.raw[i + fixed_lines].reset(&template);
}
} else {
// Subregion rotation
for line in IndexRange(region.start..(region.end - positions)) {
self.raw.swap_lines(line, line + positions);
}
// Clear reused lines
for line in IndexRange((region.end - positions)..region.end) {
self.raw[line].reset(&template);
}
}
}
// Completely reset the grid state
pub fn reset(&mut self, template: &T) {
// Explicitly purge all lines from history
let shrinkage = self.raw.len() - self.lines.0;
self.raw.shrink_lines(shrinkage);
self.clear_history();
// Reset all visible lines
for row in 0..self.raw.len() {
self.raw[row].reset(template);
}
self.display_offset = 0;
self.selection = None;
self.url_highlight = None;
}
}
#[allow(clippy::len_without_is_empty)]
impl<T> Grid<T> {
#[inline]
pub fn num_lines(&self) -> index::Line {
self.lines
}
pub fn display_iter(&self) -> DisplayIter<'_, T> {
DisplayIter::new(self)
}
#[inline]
pub fn num_cols(&self) -> index::Column {
self.cols
}
pub fn clear_history(&mut self) {
self.scroll_limit = 0;
}
#[inline]
pub fn scroll_limit(&self) -> usize {
self.scroll_limit
}
/// Total number of lines in the buffer, this includes scrollback + visible lines
#[inline]
pub fn len(&self) -> usize {
self.raw.len()
}
#[inline]
pub fn history_size(&self) -> usize {
self.raw.len().saturating_sub(*self.lines)
}
/// This is used only for initializing after loading ref-tests
pub fn initialize_all(&mut self, template: &T)
where
T: Copy,
{
let history_size = self.raw.len().saturating_sub(*self.lines);
self.raw.initialize(self.max_scroll_limit - history_size, Row::new(self.cols, template));
}
/// This is used only for truncating before saving ref-tests
pub fn truncate(&mut self) {
self.raw.truncate();
}
pub fn iter_from(&self, point: Point<usize>) -> GridIterator<'_, T> {
GridIterator { grid: self, cur: point }
}
#[inline]
pub fn contains(&self, point: &Point) -> bool {
self.lines > point.line && self.cols > point.col
}
#[inline]
pub fn display_offset(&self) -> usize {
self.display_offset
}
}
pub struct GridIterator<'a, T> {
/// Immutable grid reference
grid: &'a Grid<T>,
/// Current position of the iterator within the grid.
pub cur: Point<usize>,
}
impl<'a, T> Iterator for GridIterator<'a, T> {
type Item = &'a T;
fn next(&mut self) -> Option<Self::Item> {
let last_col = self.grid.num_cols() - Column(1);
match self.cur {
Point { line, col } if line == 0 && col == last_col => None,
Point { col, .. } if (col == last_col) => {
self.cur.line -= 1;
self.cur.col = Column(0);
Some(&self.grid[self.cur.line][self.cur.col])
},
_ => {
self.cur.col += Column(1);
Some(&self.grid[self.cur.line][self.cur.col])
},
}
}
}
impl<'a, T> BidirectionalIterator for GridIterator<'a, T> {
fn prev(&mut self) -> Option<Self::Item> {
let num_cols = self.grid.num_cols();
match self.cur {
Point { line, col: Column(0) } if line == self.grid.len() - 1 => None,
Point { col: Column(0), .. } => {
self.cur.line += 1;
self.cur.col = num_cols - Column(1);
Some(&self.grid[self.cur.line][self.cur.col])
},
_ => {
self.cur.col -= Column(1);
Some(&self.grid[self.cur.line][self.cur.col])
},
}
}
}
/// Index active region by line
impl<T> Index<index::Line> for Grid<T> {
type Output = Row<T>;
#[inline]
fn index(&self, index: index::Line) -> &Row<T> {
&self.raw[index]
}
}
/// Index with buffer offset
impl<T> Index<usize> for Grid<T> {
type Output = Row<T>;
#[inline]
fn index(&self, index: usize) -> &Row<T> {
&self.raw[index]
}
}
impl<T> IndexMut<index::Line> for Grid<T> {
#[inline]
fn index_mut(&mut self, index: index::Line) -> &mut Row<T> {
&mut self.raw[index]
}
}
impl<T> IndexMut<usize> for Grid<T> {
#[inline]
fn index_mut(&mut self, index: usize) -> &mut Row<T> {
&mut self.raw[index]
}
}
impl<'point, T> Index<&'point Point> for Grid<T> {
type Output = T;
#[inline]
fn index<'a>(&'a self, point: &Point) -> &'a T {
&self[point.line][point.col]
}
}
impl<'point, T> IndexMut<&'point Point> for Grid<T> {
#[inline]
fn index_mut<'a, 'b>(&'a mut self, point: &'b Point) -> &'a mut T {
&mut self[point.line][point.col]
}
}
// -------------------------------------------------------------------------------------------------
// REGIONS
// -------------------------------------------------------------------------------------------------
/// A subset of lines in the grid
///
/// May be constructed using Grid::region(..)
pub struct Region<'a, T> {
start: Line,
end: Line,
raw: &'a Storage<T>,
}
/// A mutable subset of lines in the grid
///
/// May be constructed using Grid::region_mut(..)
pub struct RegionMut<'a, T> {
start: Line,
end: Line,
raw: &'a mut Storage<T>,
}
impl<'a, T> RegionMut<'a, T> {
/// Call the provided function for every item in this region
pub fn each<F: Fn(&mut T)>(self, func: F) {
for row in self {
for item in row {
func(item)
}
}
}
}
pub trait IndexRegion<I, T> {
/// Get an immutable region of Self
fn region(&self, _: I) -> Region<'_, T>;
/// Get a mutable region of Self
fn region_mut(&mut self, _: I) -> RegionMut<'_, T>;
}
impl<T> IndexRegion<Range<Line>, T> for Grid<T> {
fn region(&self, index: Range<Line>) -> Region<'_, T> {
assert!(index.start < self.num_lines());
assert!(index.end <= self.num_lines());
assert!(index.start <= index.end);
Region { start: index.start, end: index.end, raw: &self.raw }
}
fn region_mut(&mut self, index: Range<Line>) -> RegionMut<'_, T> {
assert!(index.start < self.num_lines());
assert!(index.end <= self.num_lines());
assert!(index.start <= index.end);
RegionMut { start: index.start, end: index.end, raw: &mut self.raw }
}
}
impl<T> IndexRegion<RangeTo<Line>, T> for Grid<T> {
fn region(&self, index: RangeTo<Line>) -> Region<'_, T> {
assert!(index.end <= self.num_lines());
Region { start: Line(0), end: index.end, raw: &self.raw }
}
fn region_mut(&mut self, index: RangeTo<Line>) -> RegionMut<'_, T> {
assert!(index.end <= self.num_lines());
RegionMut { start: Line(0), end: index.end, raw: &mut self.raw }
}
}
impl<T> IndexRegion<RangeFrom<Line>, T> for Grid<T> {
fn region(&self, index: RangeFrom<Line>) -> Region<'_, T> {
assert!(index.start < self.num_lines());
Region { start: index.start, end: self.num_lines(), raw: &self.raw }
}
fn region_mut(&mut self, index: RangeFrom<Line>) -> RegionMut<'_, T> {
assert!(index.start < self.num_lines());
RegionMut { start: index.start, end: self.num_lines(), raw: &mut self.raw }
}
}
impl<T> IndexRegion<RangeFull, T> for Grid<T> {
fn region(&self, _: RangeFull) -> Region<'_, T> {
Region { start: Line(0), end: self.num_lines(), raw: &self.raw }
}
fn region_mut(&mut self, _: RangeFull) -> RegionMut<'_, T> {
RegionMut { start: Line(0), end: self.num_lines(), raw: &mut self.raw }
}
}
pub struct RegionIter<'a, T> {
end: Line,
cur: Line,
raw: &'a Storage<T>,
}
pub struct RegionIterMut<'a, T> {
end: Line,
cur: Line,
raw: &'a mut Storage<T>,
}
impl<'a, T> IntoIterator for Region<'a, T> {
type IntoIter = RegionIter<'a, T>;
type Item = &'a Row<T>;
fn into_iter(self) -> Self::IntoIter {
RegionIter { end: self.end, cur: self.start, raw: self.raw }
}
}
impl<'a, T> IntoIterator for RegionMut<'a, T> {
type IntoIter = RegionIterMut<'a, T>;
type Item = &'a mut Row<T>;
fn into_iter(self) -> Self::IntoIter {
RegionIterMut { end: self.end, cur: self.start, raw: self.raw }
}
}
impl<'a, T> Iterator for RegionIter<'a, T> {
type Item = &'a Row<T>;
fn next(&mut self) -> Option<Self::Item> {
if self.cur < self.end {
let index = self.cur;
self.cur += 1;
Some(&self.raw[index])
} else {
None
}
}
}
impl<'a, T> Iterator for RegionIterMut<'a, T> {
type Item = &'a mut Row<T>;
fn next(&mut self) -> Option<Self::Item> {
if self.cur < self.end {
let index = self.cur;
self.cur += 1;
unsafe { Some(&mut *(&mut self.raw[index] as *mut _)) }
} else {
None
}
}
}
// -------------------------------------------------------------------------------------------------
// DISPLAY ITERATOR
// -------------------------------------------------------------------------------------------------
/// Iterates over the visible area accounting for buffer transform
pub struct DisplayIter<'a, T> {
grid: &'a Grid<T>,
offset: usize,
limit: usize,
col: Column,
line: Line,
}
impl<'a, T: 'a> DisplayIter<'a, T> {
pub fn new(grid: &'a Grid<T>) -> DisplayIter<'a, T> {
let offset = grid.display_offset + *grid.num_lines() - 1;
let limit = grid.display_offset;
let col = Column(0);
let line = Line(0);
DisplayIter { grid, offset, col, limit, line }
}
pub fn offset(&self) -> usize {
self.offset
}
pub fn column(&self) -> Column {
self.col
}
pub fn line(&self) -> Line {
self.line
}
}
impl<'a, T: Copy + 'a> Iterator for DisplayIter<'a, T> {
type Item = Indexed<T>;
#[inline]
fn next(&mut self) -> Option<Self::Item> {
// Return None if we've reached the end.
if self.offset == self.limit && self.grid.num_cols() == self.col {
return None;
}
// Get the next item.
let item = Some(Indexed {
inner: self.grid.raw[self.offset][self.col],
line: self.line,
column: self.col,
});
// Update line/col to point to next item
self.col += 1;
if self.col == self.grid.num_cols() && self.offset != self.limit {
self.offset -= 1;
self.col = Column(0);
self.line = Line(*self.grid.lines - 1 - (self.offset - self.limit));
}
item
}
}
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