helix-mirror/helix-core/src/indent.rs
2024-05-07 15:15:52 -04:00

1246 lines
46 KiB
Rust

use std::{borrow::Cow, collections::HashMap};
use helix_stdx::rope::RopeSliceExt;
use tree_sitter::{Query, QueryCursor, QueryPredicateArg};
use crate::{
chars::{char_is_line_ending, char_is_whitespace},
graphemes::{grapheme_width, tab_width_at},
syntax::{IndentationHeuristic, LanguageConfiguration, RopeProvider, Syntax},
tree_sitter::Node,
Position, Rope, RopeGraphemes, RopeSlice,
};
/// Enum representing indentation style.
///
/// Only values 1-8 are valid for the `Spaces` variant.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub enum IndentStyle {
Tabs,
Spaces(u8),
}
// 16 spaces
const INDENTS: &str = " ";
pub const MAX_INDENT: u8 = 16;
impl IndentStyle {
/// Creates an `IndentStyle` from an indentation string.
///
/// For example, passing `" "` (four spaces) will create `IndentStyle::Spaces(4)`.
#[allow(clippy::should_implement_trait)]
#[inline]
pub fn from_str(indent: &str) -> Self {
// XXX: do we care about validating the input more than this? Probably not...?
debug_assert!(!indent.is_empty() && indent.len() <= MAX_INDENT as usize);
if indent.starts_with(' ') {
IndentStyle::Spaces(indent.len().clamp(1, MAX_INDENT as usize) as u8)
} else {
IndentStyle::Tabs
}
}
#[inline]
pub fn as_str(&self) -> &'static str {
match *self {
IndentStyle::Tabs => "\t",
IndentStyle::Spaces(n) => {
// Unsupported indentation style. This should never happen,
debug_assert!(n > 0 && n <= MAX_INDENT);
// Either way, clamp to the nearest supported value
let closest_n = n.clamp(1, MAX_INDENT) as usize;
&INDENTS[0..closest_n]
}
}
}
#[inline]
pub fn indent_width(&self, tab_width: usize) -> usize {
match *self {
IndentStyle::Tabs => tab_width,
IndentStyle::Spaces(width) => width as usize,
}
}
}
/// Attempts to detect the indentation style used in a document.
///
/// Returns the indentation style if the auto-detect confidence is
/// reasonably high, otherwise returns `None`.
pub fn auto_detect_indent_style(document_text: &Rope) -> Option<IndentStyle> {
// Build a histogram of the indentation *increases* between
// subsequent lines, ignoring lines that are all whitespace.
//
// Index 0 is for tabs, the rest are 1-MAX_INDENT spaces.
let histogram: [usize; MAX_INDENT as usize + 1] = {
let mut histogram = [0; MAX_INDENT as usize + 1];
let mut prev_line_is_tabs = false;
let mut prev_line_leading_count = 0usize;
// Loop through the lines, checking for and recording indentation
// increases as we go.
'outer: for line in document_text.lines().take(1000) {
let mut c_iter = line.chars();
// Is first character a tab or space?
let is_tabs = match c_iter.next() {
Some('\t') => true,
Some(' ') => false,
// Ignore blank lines.
Some(c) if char_is_line_ending(c) => continue,
_ => {
prev_line_is_tabs = false;
prev_line_leading_count = 0;
continue;
}
};
// Count the line's total leading tab/space characters.
let mut leading_count = 1;
let mut count_is_done = false;
for c in c_iter {
match c {
'\t' if is_tabs && !count_is_done => leading_count += 1,
' ' if !is_tabs && !count_is_done => leading_count += 1,
// We stop counting if we hit whitespace that doesn't
// qualify as indent or doesn't match the leading
// whitespace, but we don't exit the loop yet because
// we still want to determine if the line is blank.
c if char_is_whitespace(c) => count_is_done = true,
// Ignore blank lines.
c if char_is_line_ending(c) => continue 'outer,
_ => break,
}
// Bound the worst-case execution time for weird text files.
if leading_count > 256 {
continue 'outer;
}
}
// If there was an increase in indentation over the previous
// line, update the histogram with that increase.
if (prev_line_is_tabs == is_tabs || prev_line_leading_count == 0)
&& prev_line_leading_count < leading_count
{
if is_tabs {
histogram[0] += 1;
} else {
let amount = leading_count - prev_line_leading_count;
if amount <= MAX_INDENT as usize {
histogram[amount] += 1;
}
}
}
// Store this line's leading whitespace info for use with
// the next line.
prev_line_is_tabs = is_tabs;
prev_line_leading_count = leading_count;
}
// Give more weight to tabs, because their presence is a very
// strong indicator.
histogram[0] *= 2;
histogram
};
// Find the most frequent indent, its frequency, and the frequency of
// the next-most frequent indent.
let indent = histogram
.iter()
.enumerate()
.max_by_key(|kv| kv.1)
.unwrap()
.0;
let indent_freq = histogram[indent];
let indent_freq_2 = *histogram
.iter()
.enumerate()
.filter(|kv| kv.0 != indent)
.map(|kv| kv.1)
.max()
.unwrap();
// Return the the auto-detected result if we're confident enough in its
// accuracy, based on some heuristics.
if indent_freq >= 1 && (indent_freq_2 as f64 / indent_freq as f64) < 0.66 {
Some(match indent {
0 => IndentStyle::Tabs,
_ => IndentStyle::Spaces(indent as u8),
})
} else {
None
}
}
/// To determine indentation of a newly inserted line, figure out the indentation at the last col
/// of the previous line.
pub fn indent_level_for_line(line: RopeSlice, tab_width: usize, indent_width: usize) -> usize {
let mut len = 0;
for ch in line.chars() {
match ch {
'\t' => len += tab_width_at(len, tab_width as u16),
' ' => len += 1,
_ => break,
}
}
len / indent_width
}
/// Create a string of tabs & spaces that has the same visual width as the given RopeSlice (independent of the tab width).
fn whitespace_with_same_width(text: RopeSlice) -> String {
let mut s = String::new();
for grapheme in RopeGraphemes::new(text) {
if grapheme == "\t" {
s.push('\t');
} else {
s.extend(std::iter::repeat(' ').take(grapheme_width(&Cow::from(grapheme))));
}
}
s
}
fn add_indent_level(
mut base_indent: String,
added_indent_level: isize,
indent_style: &IndentStyle,
tab_width: usize,
) -> String {
if added_indent_level >= 0 {
// Adding a non-negative indent is easy, we can simply append the indent string
base_indent.push_str(&indent_style.as_str().repeat(added_indent_level as usize));
base_indent
} else {
// In this case, we want to return a prefix of `base_indent`.
// Since the width of a tab depends on its offset, we cannot simply iterate over
// the chars of `base_indent` in reverse until we have the desired indent reduction,
// instead we iterate over them twice in forward direction.
let base_indent_rope = RopeSlice::from(base_indent.as_str());
#[allow(deprecated)]
let base_indent_width =
crate::visual_coords_at_pos(base_indent_rope, base_indent_rope.len_chars(), tab_width)
.col;
let target_indent_width = base_indent_width
.saturating_sub((-added_indent_level) as usize * indent_style.indent_width(tab_width));
#[allow(deprecated)]
let char_end_idx = crate::pos_at_visual_coords(
base_indent_rope,
Position {
row: 0,
col: target_indent_width,
},
tab_width,
);
let byte_end_idx = base_indent_rope.char_to_byte(char_end_idx);
base_indent.truncate(byte_end_idx);
base_indent
}
}
/// Return true if only whitespace comes before the node on its line.
/// If given, new_line_byte_pos is treated the same way as any existing newline.
fn is_first_in_line(node: Node, text: RopeSlice, new_line_byte_pos: Option<usize>) -> bool {
let mut line_start_byte_pos = text.line_to_byte(node.start_position().row);
if let Some(pos) = new_line_byte_pos {
if line_start_byte_pos < pos && pos <= node.start_byte() {
line_start_byte_pos = pos;
}
}
text.byte_slice(line_start_byte_pos..node.start_byte())
.chars()
.all(|c| c.is_whitespace())
}
/// The total indent for some line of code.
/// This is usually constructed in one of 2 ways:
/// - Successively add indent captures to get the (added) indent from a single line
/// - Successively add the indent results for each line
/// The string that this indentation defines starts with the string contained in the align field (unless it is None), followed by:
/// - max(0, indent - outdent) tabs, if tabs are used for indentation
/// - max(0, indent - outdent)*indent_width spaces, if spaces are used for indentation
#[derive(Default, Debug, PartialEq, Eq, Clone)]
pub struct Indentation<'a> {
indent: usize,
indent_always: usize,
outdent: usize,
outdent_always: usize,
/// The alignment, as a string containing only tabs & spaces. Storing this as a string instead of e.g.
/// the (visual) width ensures that the alignment is preserved even if the tab width changes.
align: Option<RopeSlice<'a>>,
}
impl<'a> Indentation<'a> {
/// Add some other [Indentation] to this.
/// The added indent should be the total added indent from one line.
/// Indent should always be added starting from the bottom (or equivalently, the innermost tree-sitter node).
fn add_line(&mut self, added: Indentation<'a>) {
// Align overrides the indent from outer scopes.
if self.align.is_some() {
return;
}
if added.align.is_some() {
self.align = added.align;
return;
}
self.indent += added.indent;
self.indent_always += added.indent_always;
self.outdent += added.outdent;
self.outdent_always += added.outdent_always;
}
/// Add an indent capture to this indent.
/// Only captures that apply to the same line should be added together in this way (otherwise use `add_line`)
/// and the captures should be added starting from the innermost tree-sitter node (currently this only matters
/// if multiple `@align` patterns occur on the same line).
fn add_capture(&mut self, added: IndentCaptureType<'a>) {
match added {
IndentCaptureType::Indent => {
if self.indent_always == 0 {
self.indent = 1;
}
}
IndentCaptureType::IndentAlways => {
// any time we encounter an `indent.always` on the same line, we
// want to cancel out all regular indents
self.indent_always += 1;
self.indent = 0;
}
IndentCaptureType::Outdent => {
if self.outdent_always == 0 {
self.outdent = 1;
}
}
IndentCaptureType::OutdentAlways => {
self.outdent_always += 1;
self.outdent = 0;
}
IndentCaptureType::Align(align) => {
if self.align.is_none() {
self.align = Some(align);
}
}
}
}
fn net_indent(&self) -> isize {
(self.indent + self.indent_always) as isize
- ((self.outdent + self.outdent_always) as isize)
}
/// Convert `self` into a string, taking into account the computed and actual indentation of some other line.
fn relative_indent(
&self,
other_computed_indent: &Self,
other_leading_whitespace: RopeSlice,
indent_style: &IndentStyle,
tab_width: usize,
) -> Option<String> {
if self.align == other_computed_indent.align {
// If self and baseline are either not aligned to anything or both aligned the same way,
// we can simply take `other_leading_whitespace` and add some indent / outdent to it (in the second
// case, the alignment should already be accounted for in `other_leading_whitespace`).
let indent_diff = self.net_indent() - other_computed_indent.net_indent();
Some(add_indent_level(
String::from(other_leading_whitespace),
indent_diff,
indent_style,
tab_width,
))
} else {
// If the alignment of both lines is different, we cannot compare their indentation in any meaningful way
None
}
}
pub fn to_string(&self, indent_style: &IndentStyle, tab_width: usize) -> String {
add_indent_level(
self.align
.map_or_else(String::new, whitespace_with_same_width),
self.net_indent(),
indent_style,
tab_width,
)
}
}
/// An indent definition which corresponds to a capture from the indent query
#[derive(Debug)]
struct IndentCapture<'a> {
capture_type: IndentCaptureType<'a>,
scope: IndentScope,
}
#[derive(Debug, Clone, PartialEq)]
enum IndentCaptureType<'a> {
Indent,
IndentAlways,
Outdent,
OutdentAlways,
/// Alignment given as a string of whitespace
Align(RopeSlice<'a>),
}
impl<'a> IndentCaptureType<'a> {
fn default_scope(&self) -> IndentScope {
match self {
IndentCaptureType::Indent | IndentCaptureType::IndentAlways => IndentScope::Tail,
IndentCaptureType::Outdent | IndentCaptureType::OutdentAlways => IndentScope::All,
IndentCaptureType::Align(_) => IndentScope::All,
}
}
}
/// This defines which part of a node an [IndentCapture] applies to.
/// Each [IndentCaptureType] has a default scope, but the scope can be changed
/// with `#set!` property declarations.
#[derive(Debug, Clone, Copy)]
enum IndentScope {
/// The indent applies to the whole node
All,
/// The indent applies to everything except for the first line of the node
Tail,
}
/// A capture from the indent query which does not define an indent but extends
/// the range of a node. This is used before the indent is calculated.
#[derive(Debug)]
enum ExtendCapture {
Extend,
PreventOnce,
}
/// The result of running a tree-sitter indent query. This stores for
/// each node (identified by its ID) the relevant captures (already filtered
/// by predicates).
#[derive(Debug)]
struct IndentQueryResult<'a> {
indent_captures: HashMap<usize, Vec<IndentCapture<'a>>>,
extend_captures: HashMap<usize, Vec<ExtendCapture>>,
}
fn get_node_start_line(node: Node, new_line_byte_pos: Option<usize>) -> usize {
let mut node_line = node.start_position().row;
// Adjust for the new line that will be inserted
if new_line_byte_pos.map_or(false, |pos| node.start_byte() >= pos) {
node_line += 1;
}
node_line
}
fn get_node_end_line(node: Node, new_line_byte_pos: Option<usize>) -> usize {
let mut node_line = node.end_position().row;
// Adjust for the new line that will be inserted (with a strict inequality since end_byte is exclusive)
if new_line_byte_pos.map_or(false, |pos| node.end_byte() > pos) {
node_line += 1;
}
node_line
}
fn query_indents<'a>(
query: &Query,
syntax: &Syntax,
cursor: &mut QueryCursor,
text: RopeSlice<'a>,
range: std::ops::Range<usize>,
new_line_byte_pos: Option<usize>,
) -> IndentQueryResult<'a> {
let mut indent_captures: HashMap<usize, Vec<IndentCapture>> = HashMap::new();
let mut extend_captures: HashMap<usize, Vec<ExtendCapture>> = HashMap::new();
cursor.set_byte_range(range);
// Iterate over all captures from the query
for m in cursor.matches(query, syntax.tree().root_node(), RopeProvider(text)) {
// Skip matches where not all custom predicates are fulfilled
if !query.general_predicates(m.pattern_index).iter().all(|pred| {
match pred.operator.as_ref() {
"not-kind-eq?" => match (pred.args.get(0), pred.args.get(1)) {
(
Some(QueryPredicateArg::Capture(capture_idx)),
Some(QueryPredicateArg::String(kind)),
) => {
let node = m.nodes_for_capture_index(*capture_idx).next();
match node {
Some(node) => node.kind()!=kind.as_ref(),
_ => true,
}
}
_ => {
panic!("Invalid indent query: Arguments to \"not-kind-eq?\" must be a capture and a string");
}
},
"same-line?" | "not-same-line?" => {
match (pred.args.get(0), pred.args.get(1)) {
(
Some(QueryPredicateArg::Capture(capt1)),
Some(QueryPredicateArg::Capture(capt2))
) => {
let n1 = m.nodes_for_capture_index(*capt1).next();
let n2 = m.nodes_for_capture_index(*capt2).next();
match (n1, n2) {
(Some(n1), Some(n2)) => {
let n1_line = get_node_start_line(n1, new_line_byte_pos);
let n2_line = get_node_start_line(n2, new_line_byte_pos);
let same_line = n1_line == n2_line;
same_line==(pred.operator.as_ref()=="same-line?")
}
_ => true,
}
}
_ => {
panic!("Invalid indent query: Arguments to \"{}\" must be 2 captures", pred.operator);
}
}
}
"one-line?" | "not-one-line?" => match pred.args.get(0) {
Some(QueryPredicateArg::Capture(capture_idx)) => {
let node = m.nodes_for_capture_index(*capture_idx).next();
match node {
Some(node) => {
let (start_line, end_line) = (get_node_start_line(node,new_line_byte_pos), get_node_end_line(node, new_line_byte_pos));
let one_line = end_line == start_line;
one_line != (pred.operator.as_ref() == "not-one-line?")
},
_ => true,
}
}
_ => {
panic!("Invalid indent query: Arguments to \"not-kind-eq?\" must be a capture and a string");
}
},
_ => {
panic!(
"Invalid indent query: Unknown predicate (\"{}\")",
pred.operator
);
}
}
}) {
continue;
}
// A list of pairs (node_id, indent_capture) that are added by this match.
// They cannot be added to indent_captures immediately since they may depend on other captures (such as an @anchor).
let mut added_indent_captures: Vec<(usize, IndentCapture)> = Vec::new();
// The row/column position of the optional anchor in this query
let mut anchor: Option<tree_sitter::Node> = None;
for capture in m.captures {
let capture_name = query.capture_names()[capture.index as usize];
let capture_type = match capture_name {
"indent" => IndentCaptureType::Indent,
"indent.always" => IndentCaptureType::IndentAlways,
"outdent" => IndentCaptureType::Outdent,
"outdent.always" => IndentCaptureType::OutdentAlways,
// The alignment will be updated to the correct value at the end, when the anchor is known.
"align" => IndentCaptureType::Align(RopeSlice::from("")),
"anchor" => {
if anchor.is_some() {
log::error!("Invalid indent query: Encountered more than one @anchor in the same match.")
} else {
anchor = Some(capture.node);
}
continue;
}
"extend" => {
extend_captures
.entry(capture.node.id())
.or_insert_with(|| Vec::with_capacity(1))
.push(ExtendCapture::Extend);
continue;
}
"extend.prevent-once" => {
extend_captures
.entry(capture.node.id())
.or_insert_with(|| Vec::with_capacity(1))
.push(ExtendCapture::PreventOnce);
continue;
}
_ => {
// Ignore any unknown captures (these may be needed for predicates such as #match?)
continue;
}
};
let scope = capture_type.default_scope();
let mut indent_capture = IndentCapture {
capture_type,
scope,
};
// Apply additional settings for this capture
for property in query.property_settings(m.pattern_index) {
match property.key.as_ref() {
"scope" => {
indent_capture.scope = match property.value.as_deref() {
Some("all") => IndentScope::All,
Some("tail") => IndentScope::Tail,
Some(s) => {
panic!("Invalid indent query: Unknown value for \"scope\" property (\"{}\")", s);
}
None => {
panic!(
"Invalid indent query: Missing value for \"scope\" property"
);
}
}
}
_ => {
panic!(
"Invalid indent query: Unknown property \"{}\"",
property.key
);
}
}
}
added_indent_captures.push((capture.node.id(), indent_capture))
}
for (node_id, mut capture) in added_indent_captures {
// Set the anchor for all align queries.
if let IndentCaptureType::Align(_) = capture.capture_type {
let anchor = match anchor {
None => {
log::error!(
"Invalid indent query: @align requires an accompanying @anchor."
);
continue;
}
Some(anchor) => anchor,
};
capture.capture_type = IndentCaptureType::Align(
text.line(anchor.start_position().row)
.byte_slice(0..anchor.start_position().column),
);
}
indent_captures
.entry(node_id)
.or_insert_with(|| Vec::with_capacity(1))
.push(capture);
}
}
let result = IndentQueryResult {
indent_captures,
extend_captures,
};
log::trace!("indent result = {:?}", result);
result
}
/// Handle extend queries. deepest_preceding is the deepest descendant of node that directly precedes the cursor position.
/// Any ancestor of deepest_preceding which is also a descendant of node may be "extended". In that case, node will be updated,
/// so that the indent computation starts with the correct syntax node.
fn extend_nodes<'a>(
node: &mut Node<'a>,
mut deepest_preceding: Node<'a>,
extend_captures: &HashMap<usize, Vec<ExtendCapture>>,
text: RopeSlice,
line: usize,
tab_width: usize,
indent_width: usize,
) {
let mut stop_extend = false;
while deepest_preceding != *node {
let mut extend_node = false;
// This will be set to true if this node is captured, regardless of whether
// it actually will be extended (e.g. because the cursor isn't indented
// more than the node).
let mut node_captured = false;
if let Some(captures) = extend_captures.get(&deepest_preceding.id()) {
for capture in captures {
match capture {
ExtendCapture::PreventOnce => {
stop_extend = true;
}
ExtendCapture::Extend => {
node_captured = true;
// We extend the node if
// - the cursor is on the same line as the end of the node OR
// - the line that the cursor is on is more indented than the
// first line of the node
if deepest_preceding.end_position().row == line {
extend_node = true;
} else {
let cursor_indent =
indent_level_for_line(text.line(line), tab_width, indent_width);
let node_indent = indent_level_for_line(
text.line(deepest_preceding.start_position().row),
tab_width,
indent_width,
);
if cursor_indent > node_indent {
extend_node = true;
}
}
}
}
}
}
// If we encountered some `StopExtend` capture before, we don't
// extend the node even if we otherwise would
if node_captured && stop_extend {
stop_extend = false;
} else if extend_node && !stop_extend {
*node = deepest_preceding;
break;
}
// If the tree contains a syntax error, `deepest_preceding` may not
// have a parent despite being a descendant of `node`.
deepest_preceding = match deepest_preceding.parent() {
Some(parent) => parent,
None => return,
}
}
}
/// Prepare an indent query by computing:
/// - The node from which to start the query (this is non-trivial due to `@extend` captures)
/// - The indent captures for all relevant nodes.
#[allow(clippy::too_many_arguments)]
fn init_indent_query<'a, 'b>(
query: &Query,
syntax: &'a Syntax,
text: RopeSlice<'b>,
tab_width: usize,
indent_width: usize,
line: usize,
byte_pos: usize,
new_line_byte_pos: Option<usize>,
) -> Option<(Node<'a>, HashMap<usize, Vec<IndentCapture<'b>>>)> {
// The innermost tree-sitter node which is considered for the indent
// computation. It may change if some predeceding node is extended
let mut node = syntax
.tree()
.root_node()
.descendant_for_byte_range(byte_pos, byte_pos)?;
let (query_result, deepest_preceding) = {
// The query range should intersect with all nodes directly preceding
// the position of the indent query in case one of them is extended.
let mut deepest_preceding = None; // The deepest node preceding the indent query position
let mut tree_cursor = node.walk();
for child in node.children(&mut tree_cursor) {
if child.byte_range().end <= byte_pos {
deepest_preceding = Some(child);
}
}
deepest_preceding = deepest_preceding.map(|mut prec| {
// Get the deepest directly preceding node
while prec.child_count() > 0 {
prec = prec.child(prec.child_count() - 1).unwrap();
}
prec
});
let query_range = deepest_preceding
.map(|prec| prec.byte_range().end - 1..byte_pos + 1)
.unwrap_or(byte_pos..byte_pos + 1);
crate::syntax::PARSER.with(|ts_parser| {
let mut ts_parser = ts_parser.borrow_mut();
let mut cursor = ts_parser.cursors.pop().unwrap_or_default();
let query_result = query_indents(
query,
syntax,
&mut cursor,
text,
query_range,
new_line_byte_pos,
);
ts_parser.cursors.push(cursor);
(query_result, deepest_preceding)
})
};
let extend_captures = query_result.extend_captures;
// Check for extend captures, potentially changing the node that the indent calculation starts with
if let Some(deepest_preceding) = deepest_preceding {
extend_nodes(
&mut node,
deepest_preceding,
&extend_captures,
text,
line,
tab_width,
indent_width,
);
}
Some((node, query_result.indent_captures))
}
/// Use the syntax tree to determine the indentation for a given position.
/// This can be used in 2 ways:
///
/// - To get the correct indentation for an existing line (new_line=false), not necessarily equal to the current indentation.
/// - In this case, pos should be inside the first tree-sitter node on that line.
/// In most cases, this can just be the first non-whitespace on that line.
/// - To get the indentation for a new line (new_line=true). This behaves like the first usecase if the part of the current line
/// after pos were moved to a new line.
///
/// The indentation is determined by traversing all the tree-sitter nodes containing the position.
/// Each of these nodes produces some [Indentation] for:
///
/// - The line of the (beginning of the) node. This is defined by the scope `all` if this is the first node on its line.
/// - The line after the node. This is defined by:
/// - The scope `tail`.
/// - The scope `all` if this node is not the first node on its line.
/// Intuitively, `all` applies to everything contained in this node while `tail` applies to everything except for the first line of the node.
/// The indents from different nodes for the same line are then combined.
/// The result [Indentation] is simply the sum of the [Indentation] for all lines.
///
/// Specifying which line exactly an [Indentation] applies to is important because indents on the same line combine differently than indents on different lines:
/// ```ignore
/// some_function(|| {
/// // Both the function parameters as well as the contained block should be indented.
/// // Because they are on the same line, this only yields one indent level
/// });
/// ```
///
/// ```ignore
/// some_function(
/// param1,
/// || {
/// // Here we get 2 indent levels because the 'parameters' and the 'block' node begin on different lines
/// },
/// );
/// ```
#[allow(clippy::too_many_arguments)]
pub fn treesitter_indent_for_pos<'a>(
query: &Query,
syntax: &Syntax,
tab_width: usize,
indent_width: usize,
text: RopeSlice<'a>,
line: usize,
pos: usize,
new_line: bool,
) -> Option<Indentation<'a>> {
let byte_pos = text.char_to_byte(pos);
let new_line_byte_pos = new_line.then_some(byte_pos);
let (mut node, mut indent_captures) = init_indent_query(
query,
syntax,
text,
tab_width,
indent_width,
line,
byte_pos,
new_line_byte_pos,
)?;
let mut result = Indentation::default();
// We always keep track of all the indent changes on one line, in order to only indent once
// even if there are multiple "indent" nodes on the same line
let mut indent_for_line = Indentation::default();
let mut indent_for_line_below = Indentation::default();
loop {
let is_first = is_first_in_line(node, text, new_line_byte_pos);
// Apply all indent definitions for this node.
// Since we only iterate over each node once, we can remove the
// corresponding captures from the HashMap to avoid cloning them.
if let Some(definitions) = indent_captures.remove(&node.id()) {
for definition in definitions {
match definition.scope {
IndentScope::All => {
if is_first {
indent_for_line.add_capture(definition.capture_type);
} else {
indent_for_line_below.add_capture(definition.capture_type);
}
}
IndentScope::Tail => {
indent_for_line_below.add_capture(definition.capture_type);
}
}
}
}
if let Some(parent) = node.parent() {
let node_line = get_node_start_line(node, new_line_byte_pos);
let parent_line = get_node_start_line(parent, new_line_byte_pos);
if node_line != parent_line {
// Don't add indent for the line below the line of the query
if node_line < line + (new_line as usize) {
result.add_line(indent_for_line_below);
}
if node_line == parent_line + 1 {
indent_for_line_below = indent_for_line;
} else {
result.add_line(indent_for_line);
indent_for_line_below = Indentation::default();
}
indent_for_line = Indentation::default();
}
node = parent;
} else {
// Only add the indentation for the line below if that line
// is not after the line that the indentation is calculated for.
if (node.start_position().row < line)
|| (new_line && node.start_position().row == line && node.start_byte() < byte_pos)
{
result.add_line(indent_for_line_below);
}
result.add_line(indent_for_line);
break;
}
}
Some(result)
}
/// Returns the indentation for a new line.
/// This is done either using treesitter, or if that's not available by copying the indentation from the current line
#[allow(clippy::too_many_arguments)]
pub fn indent_for_newline(
language_config: Option<&LanguageConfiguration>,
syntax: Option<&Syntax>,
indent_heuristic: &IndentationHeuristic,
indent_style: &IndentStyle,
tab_width: usize,
text: RopeSlice,
line_before: usize,
line_before_end_pos: usize,
current_line: usize,
) -> String {
let indent_width = indent_style.indent_width(tab_width);
if let (
IndentationHeuristic::TreeSitter | IndentationHeuristic::Hybrid,
Some(query),
Some(syntax),
) = (
indent_heuristic,
language_config.and_then(|config| config.indent_query()),
syntax,
) {
if let Some(indent) = treesitter_indent_for_pos(
query,
syntax,
tab_width,
indent_width,
text,
line_before,
line_before_end_pos,
true,
) {
if *indent_heuristic == IndentationHeuristic::Hybrid {
// We want to compute the indentation not only based on the
// syntax tree but also on the actual indentation of a previous
// line. This makes indentation computation more resilient to
// incomplete queries, incomplete source code & differing indentation
// styles for the same language.
// However, using the indent of a previous line as a baseline may not
// make sense, e.g. if it has a different alignment than the new line.
// In order to prevent edge cases with long running times, we only try
// a constant number of (non-empty) lines.
const MAX_ATTEMPTS: usize = 4;
let mut num_attempts = 0;
for line_idx in (0..=line_before).rev() {
let line = text.line(line_idx);
let first_non_whitespace_char = match line.first_non_whitespace_char() {
Some(i) => i,
None => {
continue;
}
};
if let Some(indent) = (|| {
let computed_indent = treesitter_indent_for_pos(
query,
syntax,
tab_width,
indent_width,
text,
line_idx,
text.line_to_char(line_idx) + first_non_whitespace_char,
false,
)?;
let leading_whitespace = line.slice(0..first_non_whitespace_char);
indent.relative_indent(
&computed_indent,
leading_whitespace,
indent_style,
tab_width,
)
})() {
return indent;
}
num_attempts += 1;
if num_attempts == MAX_ATTEMPTS {
break;
}
}
}
return indent.to_string(indent_style, tab_width);
};
}
// Fallback in case we either don't have indent queries or they failed for some reason
let indent_level = indent_level_for_line(text.line(current_line), tab_width, indent_width);
indent_style.as_str().repeat(indent_level)
}
pub fn get_scopes(syntax: Option<&Syntax>, text: RopeSlice, pos: usize) -> Vec<&'static str> {
let mut scopes = Vec::new();
if let Some(syntax) = syntax {
let pos = text.char_to_byte(pos);
let mut node = match syntax
.tree()
.root_node()
.descendant_for_byte_range(pos, pos)
{
Some(node) => node,
None => return scopes,
};
scopes.push(node.kind());
while let Some(parent) = node.parent() {
scopes.push(parent.kind());
node = parent;
}
}
scopes.reverse();
scopes
}
#[cfg(test)]
mod test {
use super::*;
use crate::Rope;
#[test]
fn test_indent_level() {
let tab_width = 4;
let indent_width = 4;
let line = Rope::from(" fn new"); // 8 spaces
assert_eq!(
indent_level_for_line(line.slice(..), tab_width, indent_width),
2
);
let line = Rope::from("\t\t\tfn new"); // 3 tabs
assert_eq!(
indent_level_for_line(line.slice(..), tab_width, indent_width),
3
);
// mixed indentation
let line = Rope::from("\t \tfn new"); // 1 tab, 4 spaces, tab
assert_eq!(
indent_level_for_line(line.slice(..), tab_width, indent_width),
3
);
}
#[test]
fn test_large_indent_level() {
let tab_width = 16;
let indent_width = 16;
let line = Rope::from(" fn new"); // 16 spaces
assert_eq!(
indent_level_for_line(line.slice(..), tab_width, indent_width),
1
);
let line = Rope::from(" fn new"); // 32 spaces
assert_eq!(
indent_level_for_line(line.slice(..), tab_width, indent_width),
2
);
}
#[test]
fn add_capture() {
let indent = || Indentation {
indent: 1,
..Default::default()
};
let indent_always = || Indentation {
indent_always: 1,
..Default::default()
};
let outdent = || Indentation {
outdent: 1,
..Default::default()
};
let outdent_always = || Indentation {
outdent_always: 1,
..Default::default()
};
fn add_capture<'a>(
mut indent: Indentation<'a>,
capture: IndentCaptureType<'a>,
) -> Indentation<'a> {
indent.add_capture(capture);
indent
}
// adding an indent to no indent makes an indent
assert_eq!(
indent(),
add_capture(Indentation::default(), IndentCaptureType::Indent)
);
assert_eq!(
indent_always(),
add_capture(Indentation::default(), IndentCaptureType::IndentAlways)
);
assert_eq!(
outdent(),
add_capture(Indentation::default(), IndentCaptureType::Outdent)
);
assert_eq!(
outdent_always(),
add_capture(Indentation::default(), IndentCaptureType::OutdentAlways)
);
// adding an indent to an already indented has no effect
assert_eq!(indent(), add_capture(indent(), IndentCaptureType::Indent));
assert_eq!(
outdent(),
add_capture(outdent(), IndentCaptureType::Outdent)
);
// adding an always to a regular makes it always
assert_eq!(
indent_always(),
add_capture(indent(), IndentCaptureType::IndentAlways)
);
assert_eq!(
outdent_always(),
add_capture(outdent(), IndentCaptureType::OutdentAlways)
);
// adding an always to an always is additive
assert_eq!(
Indentation {
indent_always: 2,
..Default::default()
},
add_capture(indent_always(), IndentCaptureType::IndentAlways)
);
assert_eq!(
Indentation {
outdent_always: 2,
..Default::default()
},
add_capture(outdent_always(), IndentCaptureType::OutdentAlways)
);
// adding regular to always should be associative
assert_eq!(
Indentation {
indent_always: 1,
..Default::default()
},
add_capture(
add_capture(indent(), IndentCaptureType::Indent),
IndentCaptureType::IndentAlways
)
);
assert_eq!(
Indentation {
indent_always: 1,
..Default::default()
},
add_capture(
add_capture(indent(), IndentCaptureType::IndentAlways),
IndentCaptureType::Indent
)
);
assert_eq!(
Indentation {
outdent_always: 1,
..Default::default()
},
add_capture(
add_capture(outdent(), IndentCaptureType::Outdent),
IndentCaptureType::OutdentAlways
)
);
assert_eq!(
Indentation {
outdent_always: 1,
..Default::default()
},
add_capture(
add_capture(outdent(), IndentCaptureType::OutdentAlways),
IndentCaptureType::Outdent
)
);
}
#[test]
fn test_relative_indent() {
let indent_style = IndentStyle::Spaces(4);
let tab_width: usize = 4;
let no_align = [
Indentation::default(),
Indentation {
indent: 1,
..Default::default()
},
Indentation {
indent: 5,
outdent: 1,
..Default::default()
},
];
let align = no_align.clone().map(|indent| Indentation {
align: Some(RopeSlice::from("12345")),
..indent
});
let different_align = Indentation {
align: Some(RopeSlice::from("123456")),
..Default::default()
};
// Check that relative and absolute indentation computation are the same when the line we compare to is
// indented as we expect.
let check_consistency = |indent: &Indentation, other: &Indentation| {
assert_eq!(
indent.relative_indent(
other,
RopeSlice::from(other.to_string(&indent_style, tab_width).as_str()),
&indent_style,
tab_width
),
Some(indent.to_string(&indent_style, tab_width))
);
};
for a in &no_align {
for b in &no_align {
check_consistency(a, b);
}
}
for a in &align {
for b in &align {
check_consistency(a, b);
}
}
// Relative indent computation makes no sense if the alignment differs
assert_eq!(
align[0].relative_indent(
&no_align[0],
RopeSlice::from(" "),
&indent_style,
tab_width
),
None
);
assert_eq!(
align[0].relative_indent(
&different_align,
RopeSlice::from(" "),
&indent_style,
tab_width
),
None
);
}
}