mod breadcrumb;
mod diff_view;
mod input;
pub(crate) mod palette;
mod render;
mod syntax_state;
mod terminal;
use std::{
io::{self, Write},
time::Duration,
};
use anyhow::{Context, Result};
use breadcrumb::JsonBreadcrumbCache;
use crossterm::{
event,
event::{DisableMouseCapture, EnableMouseCapture},
execute,
terminal::{EnterAlternateScreen, LeaveAlternateScreen, disable_raw_mode, enable_raw_mode},
};
use ratatui::{
backend::CrosstermBackend,
layout::{Rect, Size},
text::Line,
};
#[cfg(test)]
use crate::load::IndexedTempFile;
use crate::load::ViewFile;
use crate::syntax::SyntaxKind;
use input::{
ViewState, drain_events, process_search_index_step, process_search_step, reset_top_row_offset,
};
use render::{
LineWindowCache, RenderContext, RenderRequest, RenderedLineCache, TailPositionCache,
ViewPosition, ViewportRenderOptions, continuation_indent, effective_top_row_offset,
exact_top_line_tail_offset, format_count, is_after_tail, last_full_logical_page_top,
line_number_digits, next_wrap_end, prewarm_render_cache, render_row_limit, render_viewport,
rendered_row_count, viewer_progress_percent,
};
use syntax_state::MarkdownSyntaxCache;
#[cfg(test)]
use terminal::draw_cells;
use terminal::{TerminalFrame, ViewerTerminal};
const EVENT_POLL_INTERVAL: Duration = Duration::from_millis(50);
const EVENT_DRAIN_BUDGET: Duration = Duration::from_millis(8);
const EVENT_DRAIN_LIMIT: usize = 512;
const MOUSE_SCROLL_LINES: usize = 1;
const MOUSE_HORIZONTAL_COLUMNS: usize = 4;
const RENDER_CACHE_MAX_LINES: usize = 512;
const RENDER_CACHE_MAX_ROWS_PER_LINE: usize = 256;
const WRAP_RENDER_CHUNK_ROWS: usize = 64;
const WRAP_RENDER_CHUNKS_PER_LINE: usize = 64;
const WRAP_CHECKPOINT_INTERVAL_ROWS: usize = 256;
const TERMINAL_SCROLL_HINT_MAX_ROWS: usize = 12;
const WRAP_PREWARM_LOGICAL_LINES: usize = 4;
const WRAP_GUTTER_MINOR_TICK_ROWS: usize = 8;
const WRAP_GUTTER_MAJOR_TICK_ROWS: usize = 64;
const PREWARM_PAGES: usize = 2;
const PREWARM_MAX_LINES: usize = 192;
const PREWARM_MAX_LINE_BYTES: usize = 16 * 1024;
const PREWARM_BUDGET: Duration = Duration::from_millis(4);
const LAZY_PRELOAD_LINES: usize = 4096;
const LAZY_PRELOAD_RECORDS: usize = 64;
const LAZY_PRELOAD_BUDGET: Duration = Duration::from_millis(6);
const JUMP_BUFFER_MAX_DIGITS: usize = 20;
const SEARCH_CHUNK_LINES: usize = 4096;
const TAIL_ROW_OFFSET: usize = usize::MAX;
pub fn run(file: Box<dyn ViewFile>, mode: SyntaxKind) -> Result<()> {
run_terminal(|terminal| run_loop(terminal, file.as_ref(), mode))
}
pub(crate) fn run_diff(view: crate::diff::DiffView) -> Result<()> {
run_terminal(|terminal| diff_view::run_loop(terminal, view))
}
fn run_terminal<F>(run_loop: F) -> Result<()>
where
F: FnOnce(&mut ViewerTerminal<CrosstermBackend<io::Stdout>>) -> Result<()>,
{
let mut stdout = io::stdout();
enable_raw_mode().context("failed to enable raw mode")?;
let mut cleanup = TerminalCleanup::active();
execute!(stdout, EnterAlternateScreen, EnableMouseCapture)
.context("failed to enter alternate screen")?;
let backend = CrosstermBackend::new(stdout);
let mut terminal = ViewerTerminal::new(backend);
let result = run_loop(&mut terminal);
disable_raw_mode().ok();
execute!(
terminal.backend_mut(),
DisableMouseCapture,
LeaveAlternateScreen
)
.ok();
cleanup.disarm();
terminal.show_cursor().ok();
result
}
struct TerminalCleanup {
active: bool,
}
impl TerminalCleanup {
fn active() -> Self {
Self { active: true }
}
fn disarm(&mut self) {
self.active = false;
}
}
impl Drop for TerminalCleanup {
fn drop(&mut self) {
if !self.active {
return;
}
disable_raw_mode().ok();
let mut stdout = io::stdout();
execute!(stdout, DisableMouseCapture, LeaveAlternateScreen).ok();
stdout.flush().ok();
}
}
fn run_loop(
terminal: &mut ViewerTerminal<CrosstermBackend<io::Stdout>>,
file: &dyn ViewFile,
mode: SyntaxKind,
) -> Result<()> {
let mut state = ViewState::default();
let mut dirty = true;
let mut caches = ViewerCaches::default();
loop {
if state.search_task.is_some() {
dirty |= process_search_step(file, &mut state)?;
}
if state
.search_index
.as_ref()
.is_some_and(|index| !index.exact)
{
dirty |= process_search_index_step(file, &mut state)?;
}
if dirty {
draw_view(terminal, file, mode, &mut state, &mut caches)?;
dirty = false;
}
let poll_interval = if state.search_task.is_some() {
Duration::ZERO
} else {
EVENT_POLL_INTERVAL
};
if !event::poll(poll_interval).context("failed to poll terminal event")? {
dirty |= file.preload(
LAZY_PRELOAD_LINES,
LAZY_PRELOAD_RECORDS,
LAZY_PRELOAD_BUDGET,
)?;
continue;
}
let page = terminal
.size()
.map(|size| usize::from(size.height.saturating_sub(4)).max(1))
.unwrap_or(20);
let action = drain_events(&mut state, file.line_count(), file.line_count_exact(), page)?;
if action.quit {
break;
}
if let Some(enabled) = action.mouse_capture {
apply_mouse_capture(terminal, enabled)?;
}
dirty |= action.dirty;
}
Ok(())
}
fn apply_mouse_capture(
terminal: &mut ViewerTerminal<CrosstermBackend<io::Stdout>>,
enabled: bool,
) -> Result<()> {
if enabled {
execute!(terminal.backend_mut(), EnableMouseCapture)
.context("failed to enable mouse capture")?;
} else {
execute!(terminal.backend_mut(), DisableMouseCapture)
.context("failed to disable mouse capture")?;
}
Ok(())
}
#[derive(Default)]
struct ViewerCaches {
line: LineWindowCache,
render: RenderedLineCache,
markdown: MarkdownSyntaxCache,
tail: TailPositionCache,
breadcrumb: JsonBreadcrumbCache,
}
#[derive(Debug, Clone, Copy)]
struct DrawLayout {
area: Rect,
visible_width: usize,
base_visible_height: usize,
gutter_width: usize,
selection_mode: bool,
context: RenderContext,
}
struct StickyLayout {
lines: Vec<Line<'static>>,
visible_height: usize,
tail: Option<ViewPosition>,
}
fn draw_view(
terminal: &mut ViewerTerminal<CrosstermBackend<io::Stdout>>,
file: &dyn ViewFile,
mode: SyntaxKind,
state: &mut ViewState,
caches: &mut ViewerCaches,
) -> Result<()> {
let size = terminal.size().context("failed to read terminal size")?;
let layout = draw_layout(size, file, state, mode);
let mut sticky = sync_sticky_layout(
file,
mode,
state,
&mut caches.breadcrumb,
&mut caches.tail,
layout,
)?;
resolve_search_target_from_view(
file,
state,
&mut caches.line,
sticky.visible_height,
layout.context,
)?;
let mut lines = caches.line.read(
file,
state.top,
sticky.visible_height,
sticky.visible_height.saturating_mul(2).max(32),
)?;
if refresh_sticky_after_position_change(
file,
mode,
state,
&mut caches.breadcrumb,
&mut caches.tail,
layout,
&mut sticky,
)? {
resolve_search_target_from_view(
file,
state,
&mut caches.line,
sticky.visible_height,
layout.context,
)?;
lines = caches.line.read(
file,
state.top,
sticky.visible_height,
sticky.visible_height.saturating_mul(2).max(32),
)?;
}
let render_request = RenderRequest {
context: layout.context,
row_limit: render_row_limit(sticky.visible_height),
};
if state.top_row_offset == TAIL_ROW_OFFSET {
state.top_row_offset =
exact_top_line_tail_offset(lines.lines, sticky.visible_height, layout.context);
}
state.wrap_bounds_stale = false;
let line_modes = caches
.markdown
.line_modes(file, state.top, lines.lines, mode)?;
let mut viewport = render_viewport(
lines.lines,
state.top + 1,
state.top_row_offset,
sticky.visible_height,
render_request,
&mut caches.render,
ViewportRenderOptions {
line_modes: line_modes.as_deref(),
search_query: active_search_query(state),
},
);
let mut max_top_row_offset = effective_top_row_offset(
state.top + 1,
sticky.visible_height,
layout.context,
&caches.render,
sticky.tail,
);
if viewport.lines.is_empty() && state.top_row_offset > 0 {
state.top_row_offset = max_top_row_offset;
viewport = render_viewport(
lines.lines,
state.top + 1,
state.top_row_offset,
sticky.visible_height,
render_request,
&mut caches.render,
ViewportRenderOptions {
line_modes: line_modes.as_deref(),
search_query: active_search_query(state),
},
);
}
max_top_row_offset = effective_top_row_offset(
state.top + 1,
sticky.visible_height,
layout.context,
&caches.render,
sticky.tail,
);
if state.top_row_offset > max_top_row_offset
&& caches.render.status(state.top + 1).total_rows.is_some()
{
state.top_row_offset = max_top_row_offset;
viewport = render_viewport(
lines.lines,
state.top + 1,
state.top_row_offset,
sticky.visible_height,
render_request,
&mut caches.render,
ViewportRenderOptions {
line_modes: line_modes.as_deref(),
search_query: active_search_query(state),
},
);
max_top_row_offset = effective_top_row_offset(
state.top + 1,
sticky.visible_height,
layout.context,
&caches.render,
sticky.tail,
);
}
state.top_max_row_offset = max_top_row_offset;
let position = ViewPosition {
top: state.top,
row_offset: state.top_row_offset,
};
let scroll_hint = if state.wrap && state.mouse_capture {
terminal
.scroll_hint(position)
.or_else(|| logical_scroll_hint(terminal, &caches.render, position))
} else {
None
};
let current = if file.line_count() == 0 {
0
} else {
state.top + 1
};
let bottom = viewport
.last_line_number
.unwrap_or(current)
.min(file.line_count());
let progress = viewer_progress_percent(file, layout.context, bottom, viewport.bottom);
let styled = viewport.lines;
let display_mode = display_mode_text(state);
let title = format!(
" {} | {} lines | {}-{} | {:>3}% | {} ",
file.label(),
line_count_text(file),
current,
bottom,
progress,
display_mode
);
let footer_text = if state.search_active {
format!(
" search: {} | Enter find | Backspace edit | Esc cancel ",
state.search_buffer
)
} else if !state.jump_buffer.is_empty() {
format!(
" go to line: {} / {} | Enter jump | Backspace edit | Esc cancel ",
state.jump_buffer,
line_count_text(file)
)
} else if let Some(message) = &state.search_message {
format!(
" {message}{} | / search | n/N | Esc clear ",
search_count_suffix(state)
)
} else {
idle_footer_text(state)
};
terminal
.draw(TerminalFrame {
area: layout.area,
styled,
sticky: sticky.lines,
selection_mode: layout.selection_mode,
title,
footer_text,
position,
scroll_hint,
})
.context("failed to draw terminal frame")?;
prewarm_render_cache(
file,
&mut caches.line,
&mut caches.render,
&mut caches.markdown,
position,
sticky.visible_height,
render_request,
);
Ok(())
}
fn draw_layout(size: Size, file: &dyn ViewFile, state: &ViewState, mode: SyntaxKind) -> DrawLayout {
let selection_mode = !state.mouse_capture;
let area = Rect::new(0, 0, size.width, size.height);
let visible_width = if selection_mode {
usize::from(size.width)
} else {
usize::from(size.width.saturating_sub(2))
};
let base_visible_height = if selection_mode {
usize::from(size.height.saturating_sub(1))
} else {
usize::from(size.height.saturating_sub(3))
};
let gutter_digits = if selection_mode {
0
} else if file.line_count_exact() {
line_number_digits(file.line_count())
} else {
line_number_digits(file.line_count()).max(4)
};
let gutter_width = if gutter_digits == 0 {
0
} else {
gutter_digits + 3
};
let content_width = visible_width.saturating_sub(gutter_width);
DrawLayout {
area,
visible_width,
base_visible_height,
gutter_width,
selection_mode,
context: RenderContext {
gutter_digits,
x: state.x,
width: content_width,
wrap: state.wrap,
mode,
},
}
}
fn sync_sticky_layout(
file: &dyn ViewFile,
mode: SyntaxKind,
state: &mut ViewState,
breadcrumb: &mut JsonBreadcrumbCache,
tail_cache: &mut TailPositionCache,
layout: DrawLayout,
) -> Result<StickyLayout> {
let mut lines = Vec::new();
let mut visible_height = layout.base_visible_height;
let mut tail = None;
for _ in 0..3 {
tail = adjust_state_for_visible_height(
file,
state,
visible_height,
layout.context,
tail_cache,
)?;
let next_lines = sticky_lines(
mode,
breadcrumb,
file,
state.top,
layout.visible_width,
layout.gutter_width,
layout.base_visible_height,
);
let next_visible_height =
visible_height_for_sticky(layout.base_visible_height, next_lines.len());
let stable = next_visible_height == visible_height;
lines = next_lines;
visible_height = next_visible_height;
if stable {
break;
}
}
Ok(StickyLayout {
lines,
visible_height,
tail,
})
}
fn resolve_search_target_from_view(
file: &dyn ViewFile,
state: &mut ViewState,
line_cache: &mut LineWindowCache,
visible_height: usize,
render_context: RenderContext,
) -> Result<()> {
for _ in 0..3 {
let lines = line_cache.read(
file,
state.top,
visible_height,
visible_height.saturating_mul(2).max(32),
)?;
if !resolve_search_target_position(state, lines.lines, visible_height, render_context) {
break;
}
}
Ok(())
}
fn refresh_sticky_after_position_change(
file: &dyn ViewFile,
mode: SyntaxKind,
state: &mut ViewState,
breadcrumb: &mut JsonBreadcrumbCache,
tail_cache: &mut TailPositionCache,
layout: DrawLayout,
sticky: &mut StickyLayout,
) -> Result<bool> {
let final_lines = sticky_lines(
mode,
breadcrumb,
file,
state.top,
layout.visible_width,
layout.gutter_width,
layout.base_visible_height,
);
if final_lines.len() == sticky.lines.len() {
sticky.lines = final_lines;
return Ok(false);
}
sticky.lines = final_lines;
sticky.visible_height =
visible_height_for_sticky(layout.base_visible_height, sticky.lines.len());
sticky.tail = adjust_state_for_visible_height(
file,
state,
sticky.visible_height,
layout.context,
tail_cache,
)?;
sticky.lines = sticky_lines(
mode,
breadcrumb,
file,
state.top,
layout.visible_width,
layout.gutter_width,
layout.base_visible_height,
);
Ok(true)
}
fn adjust_state_for_visible_height(
file: &dyn ViewFile,
state: &mut ViewState,
visible_height: usize,
render_context: RenderContext,
tail_cache: &mut TailPositionCache,
) -> Result<Option<ViewPosition>> {
let logical_tail_top = last_full_logical_page_top(file.line_count(), visible_height);
let tail = if file.line_count_exact() && (!state.wrap || state.top >= logical_tail_top) {
Some(tail_cache.position(file, visible_height, render_context)?)
} else {
None
};
if let Some(tail) = tail.filter(|tail| is_after_tail(state, *tail)) {
state.top = tail.top;
state.top_row_offset = tail.row_offset;
state.top_max_row_offset = 0;
state.wrap_bounds_stale = state.wrap;
}
let max_top = file.line_count().saturating_sub(1);
if file.line_count_exact() && state.top > max_top {
state.top = max_top;
reset_top_row_offset(state);
}
Ok(tail)
}
fn sticky_lines(
mode: SyntaxKind,
breadcrumb: &mut JsonBreadcrumbCache,
file: &dyn ViewFile,
top: usize,
width: usize,
gutter_width: usize,
base_visible_height: usize,
) -> Vec<Line<'static>> {
if mode == SyntaxKind::Structured {
breadcrumb.render(file, top, width, gutter_width, base_visible_height)
} else {
Vec::new()
}
}
fn visible_height_for_sticky(base_visible_height: usize, sticky_rows: usize) -> usize {
base_visible_height.saturating_sub(sticky_rows).max(1)
}
fn active_search_query(state: &ViewState) -> Option<&str> {
(!state.search_query.is_empty()).then_some(state.search_query.as_str())
}
fn resolve_search_target_position(
state: &mut ViewState,
lines: &[String],
visible_height: usize,
context: RenderContext,
) -> bool {
let Some(target) = state.search_target else {
return false;
};
let context_rows = search_context_rows(visible_height);
match target_visual_position_in_window(lines, state.top, target, context) {
Some(position)
if visual_row_is_visible(position.row, state.top_row_offset, visible_height) =>
{
state.search_target = None;
false
}
Some(position) if target.line == state.top => {
state.top_row_offset = position.row_in_line.saturating_sub(context_rows);
state.top_max_row_offset = 0;
state.search_target = None;
false
}
Some(position) if position.row_in_line > context_rows => {
position_search_target_visual_line(
state,
target.line,
position.row_in_line,
context_rows,
)
}
Some(position) => {
if position_search_target_logical_line(state, target.line, visible_height) {
true
} else {
position_search_target_visual_line(
state,
target.line,
position.row_in_line,
context_rows,
)
}
}
None => position_search_target_logical_line(state, target.line, visible_height),
}
}
fn position_search_target_visual_line(
state: &mut ViewState,
target_line: usize,
target_row: usize,
context_rows: usize,
) -> bool {
let old_top = state.top;
state.top = target_line;
state.top_row_offset = target_row.saturating_sub(context_rows);
state.top_max_row_offset = 0;
state.wrap_bounds_stale = state.wrap;
state.search_target = None;
state.top != old_top
}
fn position_search_target_logical_line(
state: &mut ViewState,
target_line: usize,
visible_height: usize,
) -> bool {
let next_top = target_line.saturating_sub(search_context_rows(visible_height));
if state.top == next_top && state.top_row_offset == 0 {
state.search_target = None;
return false;
}
state.top = next_top;
state.top_row_offset = 0;
state.top_max_row_offset = 0;
state.wrap_bounds_stale = state.wrap;
true
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct TargetVisualPosition {
row: usize,
row_in_line: usize,
}
fn target_visual_position_in_window(
lines: &[String],
first_line: usize,
target: input::SearchTarget,
context: RenderContext,
) -> Option<TargetVisualPosition> {
let target_index = target.line.checked_sub(first_line)?;
if target_index >= lines.len() {
return None;
}
let mut row = 0_usize;
for (index, line) in lines.iter().enumerate() {
if index == target_index {
let row_in_line = visual_row_for_byte(line, target.byte_index, context);
return Some(TargetVisualPosition {
row: row.saturating_add(row_in_line),
row_in_line,
});
}
row = row.saturating_add(rendered_row_count(line, context));
}
None
}
fn visual_row_is_visible(row: usize, top_row_offset: usize, visible_height: usize) -> bool {
visible_height > 0
&& row >= top_row_offset
&& row.saturating_sub(top_row_offset) < visible_height
}
fn search_context_rows(visible_height: usize) -> usize {
if visible_height < 4 {
return 0;
}
(visible_height / 3)
.clamp(2, 8)
.min(visible_height.saturating_sub(1))
}
fn visual_row_for_byte(line: &str, byte_index: usize, context: RenderContext) -> usize {
if !context.wrap || line.is_empty() || context.width == 0 {
return 0;
}
let target_byte = floor_char_boundary(line, byte_index.min(line.len()));
let continuation_indent = continuation_indent(line, context.width);
let mut start_byte = 0_usize;
let mut start_char = 0_usize;
let mut row = 0_usize;
while start_byte < line.len() {
let indent = if row > 0 {
continuation_indent.min(context.width.saturating_sub(1))
} else {
0
};
let row_width = context.width.saturating_sub(indent).max(1);
let (end_byte, end_char) = next_wrap_end(line, start_byte, start_char, row_width);
if target_byte < end_byte || end_byte >= line.len() {
return row;
}
start_byte = end_byte.max(start_byte.saturating_add(1)).min(line.len());
start_char = end_char.max(start_char.saturating_add(1));
row = row.saturating_add(1);
}
row
}
fn floor_char_boundary(text: &str, mut index: usize) -> usize {
while index > 0 && !text.is_char_boundary(index) {
index -= 1;
}
index
}
fn logical_scroll_hint(
terminal: &ViewerTerminal<CrosstermBackend<io::Stdout>>,
render_cache: &RenderedLineCache,
position: ViewPosition,
) -> Option<terminal::ScrollHint> {
let previous = terminal.previous_position()?;
if previous.row_offset != 0 || position.row_offset != 0 {
return None;
}
if position.top == previous.top.saturating_add(1) {
return known_line_rows(render_cache, previous.top).map(terminal::ScrollHint::up);
}
if previous.top == position.top.saturating_add(1) {
return known_line_rows(render_cache, position.top).map(terminal::ScrollHint::down);
}
None
}
fn known_line_rows(render_cache: &RenderedLineCache, zero_based_line: usize) -> Option<u16> {
let rows = render_cache.status(zero_based_line + 1).total_rows?;
if rows == 0 || rows > TERMINAL_SCROLL_HINT_MAX_ROWS {
return None;
}
u16::try_from(rows).ok()
}
fn idle_footer_text(state: &ViewState) -> String {
let wrap_hint = if state.wrap { "w unwrap" } else { "w wrap" };
let mouse_hint = if state.mouse_capture {
"m select"
} else {
"m mouse"
};
let position = wrap_position_text(state)
.map(|position| format!("{position} | "))
.unwrap_or_default();
let search = search_count_text(state)
.map(|count| format!("{count} | "))
.unwrap_or_default();
format!(
" {position}{search}q/Esc quit | {wrap_hint} | {mouse_hint} | / search n/N | wheel/j/k | 123 Enter | Space/f,b "
)
}
fn search_count_suffix(state: &ViewState) -> String {
search_count_text(state)
.map(|count| format!(" | {count}"))
.unwrap_or_default()
}
fn search_count_text(state: &ViewState) -> Option<String> {
let index = state.search_index.as_ref()?;
if index.query != state.search_query {
return None;
}
let suffix = if index.exact { "" } else { "+" };
let matches = state
.search_match_ordinal
.map(|ordinal| index.matches.max(ordinal))
.unwrap_or(index.matches);
let noun = if matches == 1 { "match" } else { "matches" };
if let Some(ordinal) = state.search_match_ordinal {
return Some(format!(
"{}/{}{suffix} {noun}",
format_count(ordinal),
format_count(matches)
));
}
Some(format!("{}{suffix} {noun}", format_count(matches)))
}
fn display_mode_text(state: &ViewState) -> String {
if state.wrap {
return wrap_position_text(state)
.map(|position| format!("wrap {position}"))
.unwrap_or_else(|| "wrap".to_owned());
}
format!("nowrap x:{}", state.x)
}
fn line_count_text(file: &dyn ViewFile) -> String {
let count = file.line_count();
if file.line_count_exact() {
count.to_string()
} else {
format!("{count}+")
}
}
fn wrap_position_text(state: &ViewState) -> Option<String> {
if !state.wrap || state.top_row_offset == 0 {
return None;
}
Some(format!("+{} rows", format_count(state.top_row_offset)))
}
#[cfg(test)]
mod tests;