helix-mods/helix-core/src/selection.rs
Blaž Hrastnik c4792efead clippy lints
2021-03-22 12:29:55 +09:00

491 lines
13 KiB
Rust

//! Selections are the primary editing construct. Even a single cursor is defined as an empty
//! single selection range.
//!
//! All positioning is done via `char` offsets into the buffer.
use crate::{Assoc, ChangeSet, Rope, RopeSlice};
use smallvec::{smallvec, SmallVec};
use std::borrow::Cow;
#[inline]
fn abs_difference(x: usize, y: usize) -> usize {
if x < y {
y - x
} else {
x - y
}
}
/// A single selection range. Anchor-inclusive, head-exclusive.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Range {
// TODO: optimize into u32
/// The anchor of the range: the side that doesn't move when extending.
pub anchor: usize,
/// The head of the range, moved when extending.
pub head: usize,
pub horiz: Option<u32>,
} // TODO: might be cheaper to store normalized as from/to and an inverted flag
impl Range {
pub fn new(anchor: usize, head: usize) -> Self {
Self {
anchor,
head,
horiz: None,
}
}
/// Start of the range.
#[inline]
#[must_use]
pub fn from(&self) -> usize {
std::cmp::min(self.anchor, self.head)
}
/// End of the range.
#[inline]
#[must_use]
pub fn to(&self) -> usize {
std::cmp::max(self.anchor, self.head)
}
/// `true` when head and anchor are at the same position.
#[inline]
pub fn is_empty(&self) -> bool {
self.anchor == self.head
}
/// Check two ranges for overlap.
#[must_use]
pub fn overlaps(&self, other: &Self) -> bool {
// cursor overlap is checked differently
if self.is_empty() {
self.from() <= other.to()
} else {
self.from() < other.to()
}
}
pub fn contains(&self, pos: usize) -> bool {
if self.is_empty() {
return false;
}
if self.anchor < self.head {
self.anchor <= pos && pos < self.head
} else {
self.head < pos && pos <= self.anchor
}
}
/// Map a range through a set of changes. Returns a new range representing the same position
/// after the changes are applied.
pub fn map(self, changes: &ChangeSet) -> Self {
let anchor = changes.map_pos(self.anchor, Assoc::After);
let head = changes.map_pos(self.head, Assoc::After);
// TODO: possibly unnecessary
if self.anchor == anchor && self.head == head {
return self;
}
Self {
anchor,
head,
horiz: None,
}
}
/// Extend the range to cover at least `from` `to`.
#[must_use]
pub fn extend(&self, from: usize, to: usize) -> Self {
if from <= self.anchor && to >= self.anchor {
return Range {
anchor: from,
head: to,
horiz: None,
};
}
Range {
anchor: self.anchor,
head: if abs_difference(from, self.anchor) > abs_difference(to, self.anchor) {
from
} else {
to
},
horiz: None,
}
}
// groupAt
#[inline]
pub fn fragment<'a, 'b: 'a>(&'a self, text: RopeSlice<'b>) -> Cow<'b, str> {
Cow::from(text.slice(self.from()..self.to() + 1))
}
}
/// A selection consists of one or more selection ranges.
/// invariant: A selection can never be empty (always contains at least primary range).
#[derive(Debug, Clone)]
pub struct Selection {
ranges: SmallVec<[Range; 1]>,
primary_index: usize,
}
#[allow(clippy::len_without_is_empty)] // a Selection is never empty
impl Selection {
// eq
#[must_use]
pub fn primary(&self) -> Range {
self.ranges[self.primary_index]
}
#[must_use]
pub fn cursor(&self) -> usize {
self.primary().head
}
/// Ensure selection containing only the primary selection.
pub fn into_single(self) -> Self {
if self.ranges.len() == 1 {
self
} else {
Self {
ranges: smallvec![self.ranges[self.primary_index]],
primary_index: 0,
}
}
}
// add_range // push
// replace_range
/// Map selections over a set of changes. Useful for adjusting the selection position after
/// applying changes to a document.
pub fn map(self, changes: &ChangeSet) -> Self {
if changes.is_empty() {
return self;
}
Self::new(
self.ranges
.into_iter()
.map(|range| range.map(changes))
.collect(),
self.primary_index,
)
}
pub fn ranges(&self) -> &[Range] {
&self.ranges
}
pub fn primary_index(&self) -> usize {
self.primary_index
}
#[must_use]
/// Constructs a selection holding a single range.
pub fn single(anchor: usize, head: usize) -> Self {
Self {
ranges: smallvec![Range {
anchor,
head,
horiz: None
}],
primary_index: 0,
}
}
/// Constructs a selection holding a single cursor.
pub fn point(pos: usize) -> Self {
Self::single(pos, pos)
}
// TODO: consume an iterator or a vec to reduce allocations?
#[must_use]
pub fn new(ranges: SmallVec<[Range; 1]>, primary_index: usize) -> Self {
assert!(!ranges.is_empty());
fn normalize(mut ranges: SmallVec<[Range; 1]>, mut primary_index: usize) -> Selection {
let primary = ranges[primary_index];
ranges.sort_unstable_by_key(Range::from);
primary_index = ranges.iter().position(|&range| range == primary).unwrap();
let mut result = SmallVec::new();
// TODO: we could do with one vec by removing elements as we mutate
for (i, range) in ranges.into_iter().enumerate() {
// if previous value exists
if let Some(prev) = result.last_mut() {
// and we overlap it
if range.overlaps(prev) {
let from = prev.from();
let to = std::cmp::max(range.to(), prev.to());
if i <= primary_index {
primary_index -= 1
}
// merge into previous
if range.anchor > range.head {
prev.anchor = to;
prev.head = from;
} else {
prev.anchor = from;
prev.head = to;
}
continue;
}
}
result.push(range)
}
Selection {
ranges: result,
primary_index,
}
}
// fast path for a single selection (cursor)
if ranges.len() == 1 {
return Selection {
ranges,
primary_index: 0,
};
}
// TODO: only normalize if needed (any ranges out of order)
normalize(ranges, primary_index)
}
/// Takes a closure and maps each selection over the closure.
pub fn transform<F>(&self, f: F) -> Self
where
F: Fn(Range) -> Range,
{
Self::new(
self.ranges.iter().copied().map(f).collect(),
self.primary_index,
)
}
pub fn fragments<'a>(&'a self, text: RopeSlice<'a>) -> impl Iterator<Item = Cow<str>> + 'a {
self.ranges.iter().map(move |range| range.fragment(text))
}
#[inline(always)]
pub fn iter(&self) -> std::slice::Iter<'_, Range> {
self.ranges.iter()
}
#[inline(always)]
pub fn len(&self) -> usize {
self.ranges.len()
}
}
impl<'a> IntoIterator for &'a Selection {
type Item = &'a Range;
type IntoIter = std::slice::Iter<'a, Range>;
fn into_iter(self) -> std::slice::Iter<'a, Range> {
self.ranges().iter()
}
}
// TODO: checkSelection -> check if valid for doc length && sorted
pub fn keep_matches(
text: RopeSlice,
selection: &Selection,
regex: &crate::regex::Regex,
) -> Option<Selection> {
let result: SmallVec<_> = selection
.iter()
.filter(|range| regex.is_match(&range.fragment(text)))
.copied()
.collect();
// TODO: figure out a new primary index
if !result.is_empty() {
return Some(Selection::new(result, 0));
}
None
}
pub fn select_on_matches(
text: RopeSlice,
selection: &Selection,
regex: &crate::regex::Regex,
) -> Option<Selection> {
let mut result = SmallVec::with_capacity(selection.len());
for sel in selection {
// TODO: can't avoid occasional allocations since Regex can't operate on chunks yet
let fragment = sel.fragment(text);
let mut sel_start = sel.from();
let sel_end = sel.to();
let mut start_byte = text.char_to_byte(sel_start);
for mat in regex.find_iter(&fragment) {
// TODO: retain range direction
let start = text.byte_to_char(start_byte + mat.start());
let end = text.byte_to_char(start_byte + mat.end());
result.push(Range::new(start, end - 1));
}
}
// TODO: figure out a new primary index
if !result.is_empty() {
return Some(Selection::new(result, 0));
}
None
}
// TODO: support to split on capture #N instead of whole match
pub fn split_on_matches(
text: RopeSlice,
selection: &Selection,
regex: &crate::regex::Regex,
) -> Selection {
let mut result = SmallVec::with_capacity(selection.len());
for sel in selection {
// TODO: can't avoid occasional allocations since Regex can't operate on chunks yet
let fragment = sel.fragment(text);
let mut sel_start = sel.from();
let sel_end = sel.to();
let mut start_byte = text.char_to_byte(sel_start);
let mut start = sel_start;
for mat in regex.find_iter(&fragment) {
// TODO: retain range direction
let end = text.byte_to_char(start_byte + mat.start());
result.push(Range::new(start, end - 1));
start = text.byte_to_char(start_byte + mat.end());
}
if start <= sel_end {
result.push(Range::new(start, sel_end));
}
}
// TODO: figure out a new primary index
Selection::new(result, 0)
}
#[cfg(test)]
mod test {
use super::*;
#[test]
#[should_panic]
fn test_new_empty() {
let sel = Selection::new(smallvec![], 0);
}
#[test]
fn test_create_normalizes_and_merges() {
let sel = Selection::new(
smallvec![
Range::new(10, 12),
Range::new(6, 7),
Range::new(4, 5),
Range::new(3, 4),
Range::new(0, 6),
Range::new(7, 8),
Range::new(9, 13),
Range::new(13, 14),
],
0,
);
let res = sel
.ranges
.into_iter()
.map(|range| format!("{}/{}", range.anchor, range.head))
.collect::<Vec<String>>()
.join(",");
assert_eq!(res, "0/6,6/7,7/8,9/13,13/14");
}
#[test]
fn test_create_merges_adjacent_points() {
let sel = Selection::new(
smallvec![
Range::new(10, 12),
Range::new(12, 12),
Range::new(12, 12),
Range::new(10, 10),
Range::new(8, 10),
],
0,
);
let res = sel
.ranges
.into_iter()
.map(|range| format!("{}/{}", range.anchor, range.head))
.collect::<Vec<String>>()
.join(",");
assert_eq!(res, "8/10,10/12");
}
#[test]
fn test_contains() {
let range = Range::new(10, 12);
assert_eq!(range.contains(9), false);
assert_eq!(range.contains(10), true);
assert_eq!(range.contains(11), true);
assert_eq!(range.contains(12), false);
assert_eq!(range.contains(13), false);
let range = Range::new(9, 6);
assert_eq!(range.contains(9), true);
assert_eq!(range.contains(7), true);
assert_eq!(range.contains(6), false);
}
#[test]
fn test_split_on_matches() {
use crate::regex::Regex;
let text = Rope::from("abcd efg wrs xyz 123 456");
let selection = Selection::new(smallvec![Range::new(0, 8), Range::new(10, 19),], 0);
let result = split_on_matches(text.slice(..), &selection, &Regex::new(r"\s+").unwrap());
assert_eq!(
result.ranges(),
&[
Range::new(0, 3),
Range::new(5, 7),
Range::new(10, 11),
Range::new(15, 17),
Range::new(19, 19),
]
);
assert_eq!(
result.fragments(text.slice(..)).collect::<Vec<_>>(),
&["abcd", "efg", "rs", "xyz", "1"]
);
}
}