1use super::{ExcerptId, MultiBufferSnapshot, ToOffset, ToPoint};
  2use anyhow::Result;
  3use std::{
  4    cmp::Ordering,
  5    ops::{Range, Sub},
  6};
  7use sum_tree::Bias;
  8use text::{rope::TextDimension, Point};
  9
 10#[derive(Clone, Eq, PartialEq, Debug, Hash)]
 11pub struct Anchor {
 12    pub(crate) buffer_id: Option<usize>,
 13    pub(crate) excerpt_id: ExcerptId,
 14    pub(crate) text_anchor: text::Anchor,
 15}
 16
 17impl Anchor {
 18    pub fn min() -> Self {
 19        Self {
 20            buffer_id: None,
 21            excerpt_id: ExcerptId::min(),
 22            text_anchor: text::Anchor::min(),
 23        }
 24    }
 25
 26    pub fn max() -> Self {
 27        Self {
 28            buffer_id: None,
 29            excerpt_id: ExcerptId::max(),
 30            text_anchor: text::Anchor::max(),
 31        }
 32    }
 33
 34    pub fn excerpt_id(&self) -> &ExcerptId {
 35        &self.excerpt_id
 36    }
 37
 38    pub fn cmp<'a>(&self, other: &Anchor, snapshot: &MultiBufferSnapshot) -> Result<Ordering> {
 39        let excerpt_id_cmp = self.excerpt_id.cmp(&other.excerpt_id);
 40        if excerpt_id_cmp.is_eq() {
 41            if self.excerpt_id == ExcerptId::min() || self.excerpt_id == ExcerptId::max() {
 42                Ok(Ordering::Equal)
 43            } else if let Some((buffer_id, buffer_snapshot)) =
 44                snapshot.buffer_snapshot_for_excerpt(&self.excerpt_id)
 45            {
 46                // Even though the anchor refers to a valid excerpt the underlying buffer might have
 47                // changed. In that case, treat the anchor as if it were at the start of that
 48                // excerpt.
 49                if self.buffer_id == Some(buffer_id) && other.buffer_id == Some(buffer_id) {
 50                    self.text_anchor.cmp(&other.text_anchor, buffer_snapshot)
 51                } else if self.buffer_id == Some(buffer_id) {
 52                    Ok(Ordering::Greater)
 53                } else if other.buffer_id == Some(buffer_id) {
 54                    Ok(Ordering::Less)
 55                } else {
 56                    Ok(Ordering::Equal)
 57                }
 58            } else {
 59                Ok(Ordering::Equal)
 60            }
 61        } else {
 62            Ok(excerpt_id_cmp)
 63        }
 64    }
 65
 66    pub fn bias_left(&self, snapshot: &MultiBufferSnapshot) -> Anchor {
 67        if self.text_anchor.bias != Bias::Left {
 68            if let Some((buffer_id, buffer_snapshot)) =
 69                snapshot.buffer_snapshot_for_excerpt(&self.excerpt_id)
 70            {
 71                if self.buffer_id == Some(buffer_id) {
 72                    return Self {
 73                        buffer_id: self.buffer_id,
 74                        excerpt_id: self.excerpt_id.clone(),
 75                        text_anchor: self.text_anchor.bias_left(buffer_snapshot),
 76                    };
 77                }
 78            }
 79        }
 80        self.clone()
 81    }
 82
 83    pub fn bias_right(&self, snapshot: &MultiBufferSnapshot) -> Anchor {
 84        if self.text_anchor.bias != Bias::Right {
 85            if let Some((buffer_id, buffer_snapshot)) =
 86                snapshot.buffer_snapshot_for_excerpt(&self.excerpt_id)
 87            {
 88                if self.buffer_id == Some(buffer_id) {
 89                    return Self {
 90                        buffer_id: self.buffer_id,
 91                        excerpt_id: self.excerpt_id.clone(),
 92                        text_anchor: self.text_anchor.bias_right(buffer_snapshot),
 93                    };
 94                }
 95            }
 96        }
 97        self.clone()
 98    }
 99
100    pub fn summary<D>(&self, snapshot: &MultiBufferSnapshot) -> D
101    where
102        D: TextDimension + Ord + Sub<D, Output = D>,
103    {
104        snapshot.summary_for_anchor(self)
105    }
106}
107
108impl ToOffset for Anchor {
109    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize {
110        self.summary(snapshot)
111    }
112}
113
114impl ToPoint for Anchor {
115    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
116        self.summary(snapshot)
117    }
118}
119
120pub trait AnchorRangeExt {
121    fn cmp(&self, b: &Range<Anchor>, buffer: &MultiBufferSnapshot) -> Result<Ordering>;
122    fn to_offset(&self, content: &MultiBufferSnapshot) -> Range<usize>;
123    fn to_point(&self, content: &MultiBufferSnapshot) -> Range<Point>;
124}
125
126impl AnchorRangeExt for Range<Anchor> {
127    fn cmp(&self, other: &Range<Anchor>, buffer: &MultiBufferSnapshot) -> Result<Ordering> {
128        Ok(match self.start.cmp(&other.start, buffer)? {
129            Ordering::Equal => other.end.cmp(&self.end, buffer)?,
130            ord @ _ => ord,
131        })
132    }
133
134    fn to_offset(&self, content: &MultiBufferSnapshot) -> Range<usize> {
135        self.start.to_offset(&content)..self.end.to_offset(&content)
136    }
137
138    fn to_point(&self, content: &MultiBufferSnapshot) -> Range<Point> {
139        self.start.to_point(&content)..self.end.to_point(&content)
140    }
141}