OXYGENHUB
# 19bb31ff1f5c oxygenhub / crates / hub / src / render / diff.rs
8.9 KiB · Rust · last changed State cache keyed by heads; history and graph through oxy-core's lanes and log window 1 month ago source blame history raw
d23464c0 Andy McCall ↶ 1 
//! Diff rendering: `oxy`'s per-file hunks become unified rows with
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//! context, and two snapshots become per-file hunks.
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use oxy_core::repo::{DiffHunk, FileDiff};
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use oxy_core::state::{FileContent, Snapshot};
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use similar::{Algorithm, DiffOp};
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use std::collections::BTreeMap;
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub enum Kind {
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    Context,
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    Add,
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    Del,
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    /// Elided lines between hunks.
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    Gap,
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}
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#[derive(Clone, Debug, PartialEq, Eq)]
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pub struct Line {
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    pub kind: Kind,
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    pub old_no: Option<u32>,
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    pub new_no: Option<u32>,
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    /// Raw text, not escaped.
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    pub text: String,
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}
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impl Kind {
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    pub fn class(self) -> &'static str {
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        match self {
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            Kind::Context => "ctx",
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            Kind::Add => "add",
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            Kind::Del => "del",
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            Kind::Gap => "gap",
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        }
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    }
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    pub fn sign(self) -> &'static str {
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        match self {
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            Kind::Context => " ",
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            Kind::Add => "+",
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            Kind::Del => "-",
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            Kind::Gap => "…",
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        }
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    }
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}
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fn text(b: &[u8]) -> String {
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    String::from_utf8_lossy(b).trim_end_matches(['\n', '\r']).to_string()
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}
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/// Unified rows for one file: `base` is the file before the change (empty
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/// for an added file) and `hunks` come from `oxy diff`, whose `base_line`
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/// is the 1-based line the additions follow (0 = before the first line).
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pub fn unified(base: &[u8], hunks: &[DiffHunk], context: usize) -> Vec<Line> {
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    let base_lines: Vec<String> = oxy_core::diff::split_lines(base).into_iter().map(text).collect();
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    // Turn hunks into a per-old-line plan: removed set, and additions keyed
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    // by the base line they follow.
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    let mut removed = std::collections::HashSet::new();
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    let mut added: BTreeMap<u32, Vec<String>> = BTreeMap::new();
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    for h in hunks {
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        for (line, _) in &h.removed {
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            removed.insert(*line);
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        }
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        added.entry(h.base_line).or_default().extend(h.added.iter().map(|b| text(b)));
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    }
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    // Walk the base, emitting rows; then trim to context around changes.
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    let mut rows: Vec<Line> = Vec::new();
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    let mut new_no: u32 = 0;
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    if let Some(lines) = added.get(&0) {
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        for l in lines {
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            new_no += 1;
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            rows.push(Line { kind: Kind::Add, old_no: None, new_no: Some(new_no), text: l.clone() });
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        }
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    }
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    for (i, l) in base_lines.iter().enumerate() {
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        let old_no = i as u32 + 1;
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        if removed.contains(&old_no) {
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            rows.push(Line { kind: Kind::Del, old_no: Some(old_no), new_no: None, text: l.clone() });
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        } else {
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            new_no += 1;
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            rows.push(Line { kind: Kind::Context, old_no: Some(old_no), new_no: Some(new_no), text: l.clone() });
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        }
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        if let Some(lines) = added.get(&old_no) {
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            for a in lines {
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                new_no += 1;
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                rows.push(Line { kind: Kind::Add, old_no: None, new_no: Some(new_no), text: a.clone() });
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            }
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        }
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    }
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    // Any additions anchored past the end (defensive).
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    for (anchor, lines) in &added {
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        if *anchor as usize > base_lines.len() {
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            for a in lines {
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                new_no += 1;
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                rows.push(Line { kind: Kind::Add, old_no: None, new_no: Some(new_no), text: a.clone() });
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            }
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        }
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    }
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    with_context(rows, context)
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}
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/// Keep `context` rows around every change, replacing longer runs with a gap.
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fn with_context(rows: Vec<Line>, context: usize) -> Vec<Line> {
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    let changed: Vec<bool> = rows.iter().map(|r| r.kind != Kind::Context).collect();
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    let mut keep = vec![false; rows.len()];
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    for (i, c) in changed.iter().enumerate() {
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        if *c {
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            let lo = i.saturating_sub(context);
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            let hi = (i + context + 1).min(rows.len());
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            for k in keep.iter_mut().take(hi).skip(lo) {
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                *k = true;
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            }
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        }
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    }
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    let mut out = Vec::new();
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    let mut gap = 0;
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    for (row, k) in rows.into_iter().zip(keep) {
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        if k {
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            if gap > 0 {
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                out.push(Line { kind: Kind::Gap, old_no: None, new_no: None, text: format!("{gap} unchanged lines") });
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                gap = 0;
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            }
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            out.push(row);
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        } else {
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            gap += 1;
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        }
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    }
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    if gap > 0 {
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        out.push(Line { kind: Kind::Gap, old_no: None, new_no: None, text: format!("{gap} unchanged lines") });
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    }
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    out
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}
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/// Hunks between two texts, in `oxy diff`'s shape.
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pub fn hunks_between(old: &[u8], new: &[u8]) -> Vec<DiffHunk> {
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    let old_lines = oxy_core::diff::split_lines(old);
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    let new_lines = oxy_core::diff::split_lines(new);
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    let ops = similar::capture_diff_slices(Algorithm::Myers, &old_lines, &new_lines);
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    let mut hunks: Vec<DiffHunk> = Vec::new();
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    for op in ops {
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        match op {
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            DiffOp::Equal { .. } => {}
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            DiffOp::Delete { old_index, old_len, .. } => {
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                hunks.push(DiffHunk {
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                    base_line: (old_index + old_len) as u32,
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                    added: vec![],
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                    removed: (old_index..old_index + old_len).map(|i| (i as u32 + 1, old_lines[i].to_vec())).collect(),
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                });
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            }
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            DiffOp::Insert { old_index, new_index, new_len } => {
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                hunks.push(DiffHunk {
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                    base_line: old_index as u32,
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                    added: (new_index..new_index + new_len).map(|i| new_lines[i].to_vec()).collect(),
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                    removed: vec![],
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                });
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            }
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            DiffOp::Replace { old_index, old_len, new_index, new_len } => {
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                hunks.push(DiffHunk {
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                    base_line: (old_index + old_len) as u32,
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                    added: (new_index..new_index + new_len).map(|i| new_lines[i].to_vec()).collect(),
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                    removed: (old_index..old_index + old_len).map(|i| (i as u32 + 1, old_lines[i].to_vec())).collect(),
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                });
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            }
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        }
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    }
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    hunks
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}
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9ff27da5 Andy McCall ↶ 169 
/// The per-file diff of one change against its base state (what
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/// `oxy diff CHANGE` shows), using an already loaded base.
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pub fn change_files(change: &oxy_core::objects::Change, base: &oxy_core::state::State, base_snapshot: &Snapshot) -> Vec<FileDiff> {
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    oxy_core::repo::diff_files_of(change, base, base_snapshot)
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}
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d23464c0 Andy McCall ↶ 175 
/// Every file that differs between two snapshots, with the base content
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/// of files present in both (for context).
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pub fn snapshot_diff(base: &Snapshot, head: &Snapshot) -> (Vec<FileDiff>, BTreeMap<String, Vec<u8>>) {
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    let mut files = Vec::new();
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    let mut bases = BTreeMap::new();
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    let text_of = |f: &oxy_core::state::FileState| match &f.content {
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        FileContent::Text { bytes, .. } => Some(bytes.clone()),
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        _ => None,
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    };
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    for (path, hf) in &head.files {
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        if hf.kind == oxy_core::objects::NodeKind::Dir {
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            continue;
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        }
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        match base.files.get(path) {
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            None => {
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                let new = text_of(hf).unwrap_or_default();
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                files.push(FileDiff { path: path.clone(), kind: "added".into(), hunks: hunks_between(b"", &new), from: None });
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            }
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            Some(bf) => {
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                let (old, new) = (text_of(bf), text_of(hf));
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                if old != new {
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                    let old_b = old.clone().unwrap_or_default();
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                    let hunks = hunks_between(&old_b, &new.unwrap_or_default());
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                    if let Some(o) = old {
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                        bases.insert(path.clone(), o);
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                    }
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                    files.push(FileDiff { path: path.clone(), kind: "modified".into(), hunks, from: None });
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                } else if bf.mode != hf.mode {
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                    files.push(FileDiff { path: path.clone(), kind: "mode".into(), hunks: vec![], from: None });
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                }
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            }
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        }
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    }
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    for (path, bf) in &base.files {
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        if bf.kind != oxy_core::objects::NodeKind::Dir && !head.files.contains_key(path) {
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            let old = text_of(bf).unwrap_or_default();
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            bases.insert(path.clone(), old.clone());
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            files.push(FileDiff { path: path.clone(), kind: "removed".into(), hunks: hunks_between(&old, b""), from: None });
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        }
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    }
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    files.sort_by(|a, b| a.path.cmp(&b.path));
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    (files, bases)
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}
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#[cfg(test)]
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mod tests {
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    use super::*;
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    #[test]
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    fn unified_rows_with_context() {
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        let base = b"a\nb\nc\nd\ne\nf\ng\nh\n";
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        let hunks = hunks_between(base, b"a\nb\nc\nX\ne\nf\ng\nh\nZ\n");
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        let rows = unified(base, &hunks, 1);
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        let s: Vec<String> = rows.iter().map(|r| format!("{}{}", r.kind.sign(), r.text)).collect();
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        assert_eq!(s, ["…2 unchanged lines", " c", "-d", "+X", " e", "…2 unchanged lines", " h", "+Z"]);
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        assert_eq!(rows[2].old_no, Some(4));
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        assert_eq!(rows[3].new_no, Some(4));
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        assert_eq!(rows.last().unwrap().new_no, Some(9));
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    }
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    #[test]
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    fn added_file() {
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        let hunks = hunks_between(b"", b"one\ntwo\n");
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        let rows = unified(b"", &hunks, 3);
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        assert_eq!(rows.iter().map(|r| r.kind).collect::<Vec<_>>(), [Kind::Add, Kind::Add]);
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    }
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}