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use std::{ num::NonZeroU8, ops::{Drop, Index, IndexMut, RangeFrom, RangeFull}, }; use crate::{ buffer::{BufferContent, CharDisplayDistances}, buffer_position::{BufferPosition, BufferRange}, }; #[derive(Debug, Default, Clone, Copy, PartialEq, Eq)] pub struct Cursor { pub anchor: BufferPosition, pub position: BufferPosition, } impl Cursor { pub const fn zero() -> Self { Self { anchor: BufferPosition::zero(), position: BufferPosition::zero(), } } pub fn to_range(&self) -> BufferRange { BufferRange::between(self.anchor, self.position) } pub fn insert(&mut self, range: BufferRange) { self.anchor = self.anchor.insert(range); self.position = self.position.insert(range); } pub fn delete(&mut self, range: BufferRange) { self.anchor = self.anchor.delete(range); self.position = self.position.delete(range); } } #[derive(Clone)] pub struct CursorCollection { cursors: Box<[Cursor; Self::capacity()]>, len: u8, saved_display_distances: Box<[u32; Self::capacity()]>, saved_display_distances_len: u8, main_cursor_index: u8, } impl CursorCollection { pub const fn capacity() -> usize { u8::MAX as _ } pub fn new() -> Self { Self { cursors: Box::new([Cursor::zero(); Self::capacity()]), len: 1, saved_display_distances: Box::new([0; Self::capacity()]), saved_display_distances_len: 0, main_cursor_index: 0, } } pub fn main_cursor_index(&self) -> usize { self.main_cursor_index as _ } pub fn main_cursor(&self) -> &Cursor { &self.cursors[self.main_cursor_index as usize] } pub fn mut_guard(&mut self) -> CursorCollectionMutGuard { CursorCollectionMutGuard { inner: self, clear_display_distances: true, } } fn sort_and_merge(&mut self) { let main_cursor = self.cursors[self.main_cursor_index as usize]; self.cursors[..self.len as usize].sort_by_key(|c| c.to_range().from); self.main_cursor_index = self.cursors[..self.len as usize] .binary_search_by_key(&main_cursor.position, |c| c.position) .unwrap_or(0) as _; let mut i = 0; while i < self.len { let mut range = self.cursors[i as usize].to_range(); for j in ((i + 1)..self.len).rev() { let other_range = self.cursors[j as usize].to_range(); if range.from <= other_range.from && other_range.from <= range.to { range.to = range.to.max(other_range.to); self.cursors .copy_within((j + 1) as usize..self.len as usize, j as _); self.len -= 1; if j <= self.main_cursor_index { self.main_cursor_index -= 1; } } } let cursor = &mut self.cursors[i as usize]; *cursor = if cursor.anchor <= cursor.position { Cursor { anchor: range.from, position: range.to, } } else { Cursor { anchor: range.to, position: range.from, } }; i += 1; } } } impl Index<usize> for CursorCollection { type Output = Cursor; fn index(&self, index: usize) -> &Self::Output { &self.cursors[index as usize] } } impl Index<RangeFull> for CursorCollection { type Output = [Cursor]; fn index(&self, _: RangeFull) -> &Self::Output { &self.cursors[..self.len as usize] } } impl Index<RangeFrom<usize>> for CursorCollection { type Output = [Cursor]; fn index(&self, index: RangeFrom<usize>) -> &Self::Output { &self.cursors[index.start..self.len as _] } } pub struct CursorCollectionMutGuard<'a> { inner: &'a mut CursorCollection, clear_display_distances: bool, } impl<'a> CursorCollectionMutGuard<'a> { pub fn clear(&mut self) { self.inner.len = 0; } pub fn add(&mut self, cursor: Cursor) { if let Some(len) = self.inner.len.checked_add(1) { self.inner.cursors[self.inner.len as usize] = cursor; self.inner.main_cursor_index = self.inner.len; self.inner.len = len; } } pub fn save_display_distances(&mut self, buffer: &BufferContent, tab_size: NonZeroU8) { self.clear_display_distances = false; if self.inner.saved_display_distances_len == 0 { for c in &self.inner.cursors[..self.inner.len as usize] { let line = &buffer.line_at(c.position.line_index as _).as_str() [..c.position.column_byte_index as usize]; let distance = CharDisplayDistances::new(line, tab_size) .last() .map(|d| d.distance) .unwrap_or(0); self.inner.saved_display_distances [self.inner.saved_display_distances_len as usize] = distance as _; self.inner.saved_display_distances_len += 1; } } } pub fn get_saved_display_distance(&self, index: usize) -> Option<u32> { if index < self.inner.saved_display_distances_len as usize { Some(self.inner.saved_display_distances[index]) } else { None } } pub fn set_main_cursor_index(&mut self, index: usize) { self.inner.main_cursor_index = index.min(CursorCollection::capacity()) as u8; } pub fn main_cursor(&mut self) -> &mut Cursor { &mut self.inner.cursors[self.inner.main_cursor_index as usize] } } impl<'a> Index<usize> for CursorCollectionMutGuard<'a> { type Output = Cursor; fn index(&self, index: usize) -> &Self::Output { &self.inner.cursors[index as usize] } } impl<'a> Index<RangeFull> for CursorCollectionMutGuard<'a> { type Output = [Cursor]; fn index(&self, _: RangeFull) -> &Self::Output { &self.inner.cursors[..self.inner.len as usize] } } impl<'a> Index<RangeFrom<usize>> for CursorCollectionMutGuard<'a> { type Output = [Cursor]; fn index(&self, index: RangeFrom<usize>) -> &Self::Output { &self.inner.cursors[index.start..self.inner.len as _] } } impl<'a> IndexMut<usize> for CursorCollectionMutGuard<'a> { fn index_mut(&mut self, index: usize) -> &mut Self::Output { &mut self.inner.cursors[index as usize] } } impl<'a> IndexMut<RangeFull> for CursorCollectionMutGuard<'a> { fn index_mut(&mut self, _: RangeFull) -> &mut Self::Output { &mut self.inner.cursors[..self.inner.len as usize] } } impl<'a> IndexMut<RangeFrom<usize>> for CursorCollectionMutGuard<'a> { fn index_mut(&mut self, index: RangeFrom<usize>) -> &mut Self::Output { &mut self.inner.cursors[index.start..self.inner.len as _] } } impl<'a> Drop for CursorCollectionMutGuard<'a> { fn drop(&mut self) { if self.inner.len == 0 { self.inner.cursors[0] = Cursor::default(); self.inner.len = 1; self.inner.main_cursor_index = 0; } self.inner.sort_and_merge(); if self.clear_display_distances { self.inner.saved_display_distances_len = 0; } } } #[cfg(test)] mod tests { use super::*; #[test] fn merge_cursor() { let mut cursors = CursorCollection::new(); assert_eq!(1, cursors[..].len()); let main_cursor = *cursors.main_cursor(); cursors.mut_guard().add(main_cursor); let mut cursors = cursors[..].iter(); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::zero(), cursor.position); assert_eq!(BufferPosition::zero(), cursor.anchor); assert!(cursors.next().is_none()); let mut cursors = CursorCollection::new(); let mut cursors_mut = cursors.mut_guard(); cursors_mut[0].anchor = BufferPosition::line_col(2, 3); cursors_mut[0].position = cursors_mut[0].anchor; drop(cursors_mut); assert_eq!(1, cursors[..].len()); cursors.mut_guard().add(Cursor { anchor: BufferPosition::line_col(2, 2), position: BufferPosition::line_col(2, 4), }); let mut cursors = cursors[..].iter(); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(2, 2), cursor.anchor); assert_eq!(BufferPosition::line_col(2, 4), cursor.position); assert!(cursors.next().is_none()); let mut cursors = CursorCollection::new(); let mut cursors_mut = cursors.mut_guard(); cursors_mut[0].anchor = BufferPosition::line_col(2, 2); cursors_mut[0].position = BufferPosition::line_col(2, 4); drop(cursors_mut); cursors.mut_guard().add(Cursor { anchor: BufferPosition::line_col(2, 2), position: BufferPosition::line_col(2, 2), }); let mut cursors = cursors[..].iter(); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(2, 2), cursor.anchor); assert_eq!(BufferPosition::line_col(2, 4), cursor.position); assert!(cursors.next().is_none()); let mut cursors = CursorCollection::new(); let mut cursors_mut = cursors.mut_guard(); cursors_mut[0].anchor = BufferPosition::line_col(2, 2); cursors_mut[0].position = BufferPosition::line_col(2, 3); drop(cursors_mut); cursors.mut_guard().add(Cursor { anchor: BufferPosition::line_col(2, 4), position: BufferPosition::line_col(2, 3), }); let mut cursors = cursors[..].iter(); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(2, 2), cursor.anchor); assert_eq!(BufferPosition::line_col(2, 4), cursor.position); assert!(cursors.next().is_none()); let mut cursors = CursorCollection::new(); let mut cursors_mut = cursors.mut_guard(); cursors_mut[0].anchor = BufferPosition::line_col(2, 4); cursors_mut[0].position = BufferPosition::line_col(2, 3); drop(cursors_mut); cursors.mut_guard().add(Cursor { anchor: BufferPosition::line_col(2, 3), position: BufferPosition::line_col(2, 2), }); let mut cursors = cursors[..].iter(); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(2, 4), cursor.anchor); assert_eq!(BufferPosition::line_col(2, 2), cursor.position); assert!(cursors.next().is_none()); } #[test] fn no_merge_cursor() { let mut cursors = CursorCollection::new(); let mut cursors_mut = cursors.mut_guard(); cursors_mut[0].anchor = BufferPosition::line_col(1, 0); cursors_mut[0].position = BufferPosition::line_col(1, 0); drop(cursors_mut); cursors.mut_guard().add(Cursor { anchor: BufferPosition::line_col(2, 0), position: BufferPosition::line_col(2, 0), }); let mut cursors = cursors[..].iter(); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(1, 0), cursor.anchor); assert_eq!(BufferPosition::line_col(1, 0), cursor.position); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(2, 0), cursor.anchor); assert_eq!(BufferPosition::line_col(2, 0), cursor.position); assert!(cursors.next().is_none()); let mut cursors = CursorCollection::new(); let mut cursors_mut = cursors.mut_guard(); cursors_mut[0].anchor = BufferPosition::line_col(3, 2); cursors_mut[0].position = BufferPosition::line_col(3, 2); drop(cursors_mut); cursors.mut_guard().add(Cursor { anchor: BufferPosition::line_col(2, 2), position: BufferPosition::line_col(2, 2), }); let mut cursors = cursors[..].iter(); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(2, 2), cursor.anchor); assert_eq!(BufferPosition::line_col(2, 2), cursor.position); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(3, 2), cursor.anchor); assert_eq!(BufferPosition::line_col(3, 2), cursor.position); assert!(cursors.next().is_none()); } #[test] fn move_and_merge_cursors() { let mut cursors = CursorCollection::new(); let mut cursors_mut = cursors.mut_guard(); cursors_mut[0].anchor = BufferPosition::line_col(0, 0); cursors_mut[0].position = BufferPosition::line_col(0, 0); drop(cursors_mut); cursors.mut_guard().add(Cursor { anchor: BufferPosition::line_col(1, 0), position: BufferPosition::line_col(1, 0), }); cursors.mut_guard().add(Cursor { anchor: BufferPosition::line_col(2, 0), position: BufferPosition::line_col(2, 0), }); assert_eq!(3, cursors[..].len()); let mut cursors_mut = cursors.mut_guard(); for c in &mut cursors_mut[..] { if c.position.line_index > 0 { c.position.line_index -= 1; } c.anchor = c.position; } drop(cursors_mut); let cursor = cursors.main_cursor(); assert_eq!(BufferPosition::line_col(1, 0), cursor.anchor); assert_eq!(BufferPosition::line_col(1, 0), cursor.position); let mut cursors = cursors[..].iter(); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(0, 0), cursor.anchor); assert_eq!(BufferPosition::line_col(0, 0), cursor.position); let cursor = cursors.next().unwrap(); assert_eq!(BufferPosition::line_col(1, 0), cursor.anchor); assert_eq!(BufferPosition::line_col(1, 0), cursor.position); assert!(cursors.next().is_none()); } }