diff options
Diffstat (limited to 'helix-core/src/selection.rs')
| -rw-r--r-- | helix-core/src/selection.rs | 513 |
1 files changed, 388 insertions, 125 deletions
diff --git a/helix-core/src/selection.rs b/helix-core/src/selection.rs index 63b9b557..074b6199 100644 --- a/helix-core/src/selection.rs +++ b/helix-core/src/selection.rs @@ -1,30 +1,50 @@ -//! Selections are the primary editing construct. Even a single cursor is defined as an empty -//! single selection range. +//! Selections are the primary editing construct. Even a single cursor is +//! defined as a single empty or 1-wide selection range. //! //! All positioning is done via `char` offsets into the buffer. -use crate::{Assoc, ChangeSet, RopeSlice}; +use crate::{ + graphemes::{ + ensure_grapheme_boundary_next, ensure_grapheme_boundary_prev, next_grapheme_boundary, + prev_grapheme_boundary, + }, + Assoc, ChangeSet, 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. +/// A single selection range. +/// +/// The range consists of an "anchor" and "head" position in +/// the text. The head is the part that the user moves when +/// directly extending the selection. The head and anchor +/// can be in any order: either can precede or follow the +/// other in the text, and they can share the same position +/// for a zero-width range. +/// +/// Below are some example `Range` configurations to better +/// illustrate. The anchor and head indices are show as +/// "(anchor, head)", followed by example text with "[" and "]" +/// inserted to visually represent the anchor and head positions: +/// +/// - (0, 3): [Som]e text. +/// - (3, 0): ]Som[e text. +/// - (2, 7): So[me te]xt. +/// - (1, 1): S[]ome text. +/// +/// Ranges are considered to be inclusive on the left and +/// exclusive on the right, regardless of anchor-head ordering. +/// This means, for example, that non-zero-width ranges that +/// are directly adjecent, sharing an edge, do not overlap. +/// However, a zero-width range will overlap with the shared +/// left-edge of another range. #[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 { @@ -53,6 +73,20 @@ impl Range { std::cmp::max(self.anchor, self.head) } + /// The (inclusive) range of lines that the range overlaps. + #[inline] + #[must_use] + pub fn line_range(&self, text: RopeSlice) -> (usize, usize) { + let from = self.from(); + let to = if self.is_empty() { + self.to() + } else { + prev_grapheme_boundary(text, self.to()).max(from) + }; + + (text.char_to_line(from), text.char_to_line(to)) + } + /// `true` when head and anchor are at the same position. #[inline] pub fn is_empty(&self) -> bool { @@ -62,25 +96,14 @@ impl Range { /// Check two ranges for overlap. #[must_use] pub fn overlaps(&self, other: &Self) -> bool { - // cursor overlap is checked differently - if self.is_empty() { - let pos = self.head; - pos >= other.from() && other.to() >= pos - } else { - self.to() > other.from() && other.to() > self.from() - } + // To my eye, it's non-obvious why this works, but I arrived + // at it after transforming the slower version that explicitly + // enumerated more cases. The unit tests are thorough. + self.from() == other.from() || (self.to() > other.from() && other.to() > self.from()) } 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 - } + self.from() <= pos && pos < self.to() } /// Map a range through a set of changes. Returns a new range representing the same position @@ -89,10 +112,10 @@ impl Range { 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; - } + // We want to return a new `Range` with `horiz == None` every time, + // even if the anchor and head haven't changed, because we don't + // know if the *visual* position hasn't changed due to + // character-width or grapheme changes earlier in the text. Self { anchor, head, @@ -103,30 +126,130 @@ impl Range { /// 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 Self { - anchor: from, - head: to, + debug_assert!(from <= to); + + if self.anchor <= self.head { + Self { + anchor: self.anchor.min(from), + head: self.head.max(to), + horiz: None, + } + } else { + Self { + anchor: self.anchor.max(to), + head: self.head.min(from), horiz: None, - }; + } } + } - Self { - anchor: self.anchor, - head: if abs_difference(from, self.anchor) > abs_difference(to, self.anchor) { - from + /// Returns a range that encompasses both input ranges. + /// + /// This is like `extend()`, but tries to negotiate the + /// anchor/head ordering between the two input ranges. + #[must_use] + pub fn merge(&self, other: Self) -> Self { + if self.anchor > self.head && other.anchor > other.head { + Range { + anchor: self.anchor.max(other.anchor), + head: self.head.min(other.head), + horiz: None, + } + } else { + Range { + anchor: self.from().min(other.from()), + head: self.to().max(other.to()), + horiz: None, + } + } + } + + /// Compute a possibly new range from this range, attempting to ensure + /// a minimum range width of 1 char by shifting the head in the forward + /// direction as needed. + /// + /// This method will never shift the anchor, and will only shift the + /// head in the forward direction. Therefore, this method can fail + /// at ensuring the minimum width if and only if the passed range is + /// both zero-width and at the end of the `RopeSlice`. + /// + /// If the input range is grapheme-boundary aligned, the returned range + /// will also be. Specifically, if the head needs to shift to achieve + /// the minimum width, it will shift to the next grapheme boundary. + #[must_use] + #[inline] + pub fn min_width_1(&self, slice: RopeSlice) -> Self { + if self.anchor == self.head { + Range { + anchor: self.anchor, + head: next_grapheme_boundary(slice, self.head), + horiz: self.horiz, + } + } else { + *self + } + } + + /// Compute a possibly new range from this range, with its ends + /// shifted as needed to align with grapheme boundaries. + /// + /// Zero-width ranges will always stay zero-width, and non-zero-width + /// ranges will never collapse to zero-width. + #[must_use] + pub fn grapheme_aligned(&self, slice: RopeSlice) -> Self { + use std::cmp::Ordering; + let (new_anchor, new_head) = match self.anchor.cmp(&self.head) { + Ordering::Equal => { + let pos = ensure_grapheme_boundary_prev(slice, self.anchor); + (pos, pos) + } + Ordering::Less => ( + ensure_grapheme_boundary_prev(slice, self.anchor), + ensure_grapheme_boundary_next(slice, self.head), + ), + Ordering::Greater => ( + ensure_grapheme_boundary_next(slice, self.anchor), + ensure_grapheme_boundary_prev(slice, self.head), + ), + }; + Range { + anchor: new_anchor, + head: new_head, + horiz: if new_anchor == self.anchor { + self.horiz } else { - to + None }, - horiz: None, } } + /// Moves the `Range` to `char_idx`. If `extend == true`, then only the head + /// is moved to `char_idx`, and the anchor is adjusted only as needed to + /// preserve 1-width range semantics. + /// + /// This method assumes that the range and `char_idx` are already properly + /// grapheme-aligned. + #[must_use] + #[inline] + pub fn put(self, text: RopeSlice, char_idx: usize, extend: bool) -> Range { + let anchor = if !extend { + char_idx + } else if self.head >= self.anchor && char_idx < self.anchor { + next_grapheme_boundary(text, self.anchor) + } else if self.head < self.anchor && char_idx >= self.anchor { + prev_grapheme_boundary(text, self.anchor) + } else { + self.anchor + }; + + Range::new(anchor, char_idx) + } + // 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)) + text.slice(self.from()..self.to()).into() } } @@ -158,8 +281,15 @@ impl Selection { } #[must_use] - pub fn cursor(&self) -> usize { - self.primary().head + pub fn cursor(&self, text: RopeSlice) -> usize { + let range = self.primary(); + + // For 1-width cursor semantics. + if range.anchor < range.head { + prev_grapheme_boundary(text, range.head) + } else { + range.head + } } /// Ensure selection containing only the primary selection. @@ -174,13 +304,12 @@ impl Selection { } } + /// Adds a new range to the selection and makes it the primary range. pub fn push(mut self, range: Range) -> Self { - let index = self.ranges.len(); self.ranges.push(range); - - Self::normalize(self.ranges, index) + self.set_primary_index(self.ranges().len() - 1); + self.normalize() } - // replace_range /// Map selections over a set of changes. Useful for adjusting the selection position after /// applying changes to a document. @@ -206,6 +335,11 @@ impl Selection { self.primary_index } + pub fn set_primary_index(&mut self, idx: usize) { + assert!(idx < self.ranges.len()); + self.primary_index = idx; + } + #[must_use] /// Constructs a selection holding a single range. pub fn single(anchor: usize, head: usize) -> Self { @@ -224,80 +358,68 @@ impl Selection { Self::single(pos, pos) } - fn normalize(mut ranges: SmallVec<[Range; 1]>, mut primary_index: usize) -> Self { - 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::with_capacity(ranges.len()); // approx - - // TODO: we could do with one vec by removing elements as we mutate - - let mut i = 0; - - for range in ranges.into_iter() { - // if previous value exists - if let Some(prev) = result.last_mut() { - // and we overlap it - - // TODO: we used to simply check range.from() <(=) prev.to() - // avoiding two comparisons - 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; - } + /// Normalizes a `Selection`. + fn normalize(mut self) -> Self { + let primary = self.ranges[self.primary_index]; + self.ranges.sort_unstable_by_key(Range::from); + self.primary_index = self + .ranges + .iter() + .position(|&range| range == primary) + .unwrap(); + + let mut prev_i = 0; + for i in 1..self.ranges.len() { + if self.ranges[prev_i].overlaps(&self.ranges[i]) { + self.ranges[prev_i] = self.ranges[prev_i].merge(self.ranges[i]); + } else { + prev_i += 1; + self.ranges[prev_i] = self.ranges[i]; + } + if i == self.primary_index { + self.primary_index = prev_i; } - - result.push(range); - i += 1 } - Self { - ranges: result, - primary_index, - } + self.ranges.truncate(prev_i + 1); + + self } // 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()); + debug_assert!(primary_index < ranges.len()); - // fast path for a single selection (cursor) - if ranges.len() == 1 { - return Self { - ranges, - primary_index: 0, - }; + let mut selection = Self { + ranges, + primary_index, + }; + + if selection.ranges.len() > 1 { + // TODO: only normalize if needed (any ranges out of order) + selection = selection.normalize(); } - // TODO: only normalize if needed (any ranges out of order) - Self::normalize(ranges, primary_index) + selection } - /// Takes a closure and maps each selection over the closure. - pub fn transform<F>(&self, f: F) -> Self + /// Takes a closure and maps each `Range` over the closure. + pub fn transform<F>(mut self, f: F) -> Self where F: Fn(Range) -> Range, { - Self::new( - self.ranges.iter().copied().map(f).collect(), - self.primary_index, - ) + for range in self.ranges.iter_mut() { + *range = f(*range) + } + + self.normalize() + } + + /// A convenience short-cut for `transform(|r| r.min_width_1(text))`. + pub fn min_width_1(self, text: RopeSlice) -> Self { + self.transform(|r| r.min_width_1(text)) } pub fn fragments<'a>(&'a self, text: RopeSlice<'a>) -> impl Iterator<Item = Cow<str>> + 'a { @@ -363,7 +485,7 @@ pub fn select_on_matches( 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.saturating_sub(1))); + result.push(Range::new(start, end)); } } @@ -384,6 +506,12 @@ pub fn split_on_matches( let mut result = SmallVec::with_capacity(selection.len()); for sel in selection { + // Special case: zero-width selection. + if sel.from() == sel.to() { + result.push(*sel); + continue; + } + // TODO: can't avoid occasional allocations since Regex can't operate on chunks yet let fragment = sel.fragment(text); @@ -396,13 +524,12 @@ pub fn split_on_matches( 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.saturating_sub(1))); + result.push(Range::new(start, end)); start = text.byte_to_char(start_byte + mat.end()); } - if start <= sel_end { + if start < sel_end { result.push(Range::new(start, sel_end)); } } @@ -484,7 +611,7 @@ mod test { .collect::<Vec<String>>() .join(","); - assert_eq!(res, "8/10,10/12"); + assert_eq!(res, "8/10,10/12,12/12"); } #[test] @@ -498,35 +625,171 @@ mod test { assert_eq!(range.contains(13), false); let range = Range::new(9, 6); - assert_eq!(range.contains(9), true); + assert_eq!(range.contains(9), false); assert_eq!(range.contains(7), true); - assert_eq!(range.contains(6), false); + assert_eq!(range.contains(6), true); + } + + #[test] + fn test_overlaps() { + fn overlaps(a: (usize, usize), b: (usize, usize)) -> bool { + Range::new(a.0, a.1).overlaps(&Range::new(b.0, b.1)) + } + + // Two non-zero-width ranges, no overlap. + assert!(!overlaps((0, 3), (3, 6))); + assert!(!overlaps((0, 3), (6, 3))); + assert!(!overlaps((3, 0), (3, 6))); + assert!(!overlaps((3, 0), (6, 3))); + assert!(!overlaps((3, 6), (0, 3))); + assert!(!overlaps((3, 6), (3, 0))); + assert!(!overlaps((6, 3), (0, 3))); + assert!(!overlaps((6, 3), (3, 0))); + + // Two non-zero-width ranges, overlap. + assert!(overlaps((0, 4), (3, 6))); + assert!(overlaps((0, 4), (6, 3))); + assert!(overlaps((4, 0), (3, 6))); + assert!(overlaps((4, 0), (6, 3))); + assert!(overlaps((3, 6), (0, 4))); + assert!(overlaps((3, 6), (4, 0))); + assert!(overlaps((6, 3), (0, 4))); + assert!(overlaps((6, 3), (4, 0))); + + // Zero-width and non-zero-width range, no overlap. + assert!(!overlaps((0, 3), (3, 3))); + assert!(!overlaps((3, 0), (3, 3))); + assert!(!overlaps((3, 3), (0, 3))); + assert!(!overlaps((3, 3), (3, 0))); + + // Zero-width and non-zero-width range, overlap. + assert!(overlaps((1, 4), (1, 1))); + assert!(overlaps((4, 1), (1, 1))); + assert!(overlaps((1, 1), (1, 4))); + assert!(overlaps((1, 1), (4, 1))); + + assert!(overlaps((1, 4), (3, 3))); + assert!(overlaps((4, 1), (3, 3))); + assert!(overlaps((3, 3), (1, 4))); + assert!(overlaps((3, 3), (4, 1))); + + // Two zero-width ranges, no overlap. + assert!(!overlaps((0, 0), (1, 1))); + assert!(!overlaps((1, 1), (0, 0))); + + // Two zero-width ranges, overlap. + assert!(overlaps((1, 1), (1, 1))); + } + + #[test] + fn test_graphem_aligned() { + let r = Rope::from_str("\r\nHi\r\n"); + let s = r.slice(..); + + // Zero-width. + assert_eq!(Range::new(0, 0).grapheme_aligned(s), Range::new(0, 0)); + assert_eq!(Range::new(1, 1).grapheme_aligned(s), Range::new(0, 0)); + assert_eq!(Range::new(2, 2).grapheme_aligned(s), Range::new(2, 2)); + assert_eq!(Range::new(3, 3).grapheme_aligned(s), Range::new(3, 3)); + assert_eq!(Range::new(4, 4).grapheme_aligned(s), Range::new(4, 4)); + assert_eq!(Range::new(5, 5).grapheme_aligned(s), Range::new(4, 4)); + assert_eq!(Range::new(6, 6).grapheme_aligned(s), Range::new(6, 6)); + + // Forward. + assert_eq!(Range::new(0, 1).grapheme_aligned(s), Range::new(0, 2)); + assert_eq!(Range::new(1, 2).grapheme_aligned(s), Range::new(0, 2)); + assert_eq!(Range::new(2, 3).grapheme_aligned(s), Range::new(2, 3)); + assert_eq!(Range::new(3, 4).grapheme_aligned(s), Range::new(3, 4)); + assert_eq!(Range::new(4, 5).grapheme_aligned(s), Range::new(4, 6)); + assert_eq!(Range::new(5, 6).grapheme_aligned(s), Range::new(4, 6)); + + assert_eq!(Range::new(0, 2).grapheme_aligned(s), Range::new(0, 2)); + assert_eq!(Range::new(1, 3).grapheme_aligned(s), Range::new(0, 3)); + assert_eq!(Range::new(2, 4).grapheme_aligned(s), Range::new(2, 4)); + assert_eq!(Range::new(3, 5).grapheme_aligned(s), Range::new(3, 6)); + assert_eq!(Range::new(4, 6).grapheme_aligned(s), Range::new(4, 6)); + + // Reverse. + assert_eq!(Range::new(1, 0).grapheme_aligned(s), Range::new(2, 0)); + assert_eq!(Range::new(2, 1).grapheme_aligned(s), Range::new(2, 0)); + assert_eq!(Range::new(3, 2).grapheme_aligned(s), Range::new(3, 2)); + assert_eq!(Range::new(4, 3).grapheme_aligned(s), Range::new(4, 3)); + assert_eq!(Range::new(5, 4).grapheme_aligned(s), Range::new(6, 4)); + assert_eq!(Range::new(6, 5).grapheme_aligned(s), Range::new(6, 4)); + + assert_eq!(Range::new(2, 0).grapheme_aligned(s), Range::new(2, 0)); + assert_eq!(Range::new(3, 1).grapheme_aligned(s), Range::new(3, 0)); + assert_eq!(Range::new(4, 2).grapheme_aligned(s), Range::new(4, 2)); + assert_eq!(Range::new(5, 3).grapheme_aligned(s), Range::new(6, 3)); + assert_eq!(Range::new(6, 4).grapheme_aligned(s), Range::new(6, 4)); + } + + #[test] + fn test_min_width_1() { + let r = Rope::from_str("\r\nHi\r\n"); + let s = r.slice(..); + + // Zero-width. + assert_eq!(Range::new(0, 0).min_width_1(s), Range::new(0, 2)); + assert_eq!(Range::new(1, 1).min_width_1(s), Range::new(1, 2)); + assert_eq!(Range::new(2, 2).min_width_1(s), Range::new(2, 3)); + assert_eq!(Range::new(3, 3).min_width_1(s), Range::new(3, 4)); + assert_eq!(Range::new(4, 4).min_width_1(s), Range::new(4, 6)); + assert_eq!(Range::new(5, 5).min_width_1(s), Range::new(5, 6)); + assert_eq!(Range::new(6, 6).min_width_1(s), Range::new(6, 6)); + + // Forward. + assert_eq!(Range::new(0, 1).min_width_1(s), Range::new(0, 1)); + assert_eq!(Range::new(1, 2).min_width_1(s), Range::new(1, 2)); + assert_eq!(Range::new(2, 3).min_width_1(s), Range::new(2, 3)); + assert_eq!(Range::new(3, 4).min_width_1(s), Range::new(3, 4)); + assert_eq!(Range::new(4, 5).min_width_1(s), Range::new(4, 5)); + assert_eq!(Range::new(5, 6).min_width_1(s), Range::new(5, 6)); + + // Reverse. + assert_eq!(Range::new(1, 0).min_width_1(s), Range::new(1, 0)); + assert_eq!(Range::new(2, 1).min_width_1(s), Range::new(2, 1)); + assert_eq!(Range::new(3, 2).min_width_1(s), Range::new(3, 2)); + assert_eq!(Range::new(4, 3).min_width_1(s), Range::new(4, 3)); + assert_eq!(Range::new(5, 4).min_width_1(s), Range::new(5, 4)); + assert_eq!(Range::new(6, 5).min_width_1(s), Range::new(6, 5)); } #[test] fn test_split_on_matches() { use crate::regex::Regex; - let text = Rope::from("abcd efg wrs xyz 123 456"); + 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 selection = Selection::new(smallvec![Range::new(0, 9), Range::new(11, 20),], 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), + // TODO: rather than this behavior, maybe we want it + // to be based on which side is the anchor? + // + // We get a leading zero-width range when there's + // a leading match because ranges are inclusive on + // the left. Imagine, for example, if the entire + // selection range were matched: you'd still want + // at least one range to remain after the split. + Range::new(0, 0), + Range::new(1, 5), + Range::new(6, 9), + Range::new(11, 13), + Range::new(16, 19), + // In contrast to the comment above, there is no + // _trailing_ zero-width range despite the trailing + // match, because ranges are exclusive on the right. ] ); assert_eq!( result.fragments(text.slice(..)).collect::<Vec<_>>(), - &["abcd", "efg", "rs", "xyz", "1"] + &["", "abcd", "efg", "rs", "xyz"] ); } } |