OXYGENHUB
# 8b53b935dd03 oxygen / crates / oxy-core / src / repo / prompt.rs
42.0 KiB · Rust · last changed Fetch reports how each bookmark stands against the remote's copy 1 month ago source blame history raw
1 
//! Fast, side-effect-free status for shell prompts.
2 
//!
3 
//! Every snapshot and checkout writes a manifest of the working copy as it
4 
//! was last seen: `size`, `mtime`, and BLAKE3 of each file. `quick_status`
5 
//! walks the working copy and compares against that manifest, reading a
6 
//! file's content only when its size or mtime changed, and records no
7 
//! operation. Ahead/behind counts come from walking the store between the
8 
//! local bookmark and its `origin` tracking state.
9
10 
use super::*;
11 
use std::time::UNIX_EPOCH;
12
13 
#[derive(Debug, Clone, Default, PartialEq, Eq)]
14 
pub struct PromptInfo {
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    pub bookmark: String,
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    /// Working-copy ChangeId prefix.
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    pub change_id: String,
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    pub heads: usize,
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    pub dirty: bool,
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    pub conflicted: bool,
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    /// Changes local `main` has that `origin/main` lacks, when tracking exists.
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    pub ahead: Option<usize>,
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    pub behind: Option<usize>,
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}
25
26 
impl PromptInfo {
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    /// The glyph for the working copy's state: `‼` conflicted, `✎` dirty,
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    /// `✔` clean.
29 
    pub fn state_glyph(&self) -> &'static str {
30 
        if self.conflicted {
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            "‼"
32 
        } else if self.dirty {
33 
            "✎"
34 
        } else {
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            "✔"
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        }
37 
    }
38
39 
    /// The ANSI colour (SGR parameter) for the state: red, yellow, or cyan.
40 
    pub fn state_color(&self) -> u8 {
41 
        if self.conflicted {
42 
            31
43 
        } else if self.dirty {
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            33
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        } else {
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            36
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        }
48 
    }
49
50 
    /// `format` wrapped in the state colour. `guard` is `("\\[", "\\]")` for
51 
    /// bash prompts, `("%{", "%}")` for zsh, or empty for raw output.
52 
    pub fn format_colored(&self, fmt: &str, guard: (&str, &str)) -> String {
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        format!(
54 
            "{}\x1b[{}m{}{}{}\x1b[0m{}",
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            guard.0,
56 
            self.state_color(),
57 
            guard.1,
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            self.format(fmt),
59 
            guard.0,
60 
            guard.1
61 
        )
62 
    }
63
64 
    /// Expand `%b` bookmark, `%c` change id, `%h` heads, `%d` dirty marker
65 
    /// (`*`), `%x` conflict marker (`!`), `%a`/`%B` ahead/behind counts
66 
    /// (empty when unknown), `%A`/`%D` `+n`/`-n` when non-zero, `%s` the
67 
    /// state glyph, `%U`/`%O` `↑n`/`↓n` when non-zero, `%i` the repository
68 
    /// icon, `%%` percent.
69 
    pub fn format(&self, fmt: &str) -> String {
70 
        let mut out = String::new();
71 
        let mut chars = fmt.chars();
72 
        while let Some(c) = chars.next() {
73 
            if c != '%' {
74 
                out.push(c);
75 
                continue;
76 
            }
77 
            match chars.next() {
78 
                Some('b') => out.push_str(&self.bookmark),
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                Some('c') => out.push_str(&self.change_id),
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                Some('h') => out.push_str(&self.heads.to_string()),
81 
                Some('d') => {
82 
                    if self.dirty {
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                        out.push('*');
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                    }
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                }
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                Some('x') => {
87 
                    if self.conflicted {
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                        out.push('!');
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                    }
90 
                }
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                Some('a') => out.push_str(&self.ahead.map(|n| n.to_string()).unwrap_or_default()),
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                Some('B') => out.push_str(&self.behind.map(|n| n.to_string()).unwrap_or_default()),
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                Some('A') => {
94 
                    if let Some(n) = self.ahead.filter(|n| *n > 0) {
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                        out.push_str(&format!("+{n}"));
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                    }
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                }
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                Some('D') => {
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                    if let Some(n) = self.behind.filter(|n| *n > 0) {
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                        out.push_str(&format!("-{n}"));
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                    }
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                }
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                Some('s') => out.push_str(self.state_glyph()),
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                Some('U') => {
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                    if let Some(n) = self.ahead.filter(|n| *n > 0) {
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                        out.push_str(&format!("↑{n}"));
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                    }
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                }
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                Some('O') => {
110 
                    if let Some(n) = self.behind.filter(|n| *n > 0) {
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                        out.push_str(&format!("↓{n}"));
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                    }
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                }
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                Some('i') => out.push_str(ICON),
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                Some('%') => out.push('%'),
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                Some(other) => {
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                    out.push('%');
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                    out.push(other);
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                }
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                None => out.push('%'),
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            }
122 
        }
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        out
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    }
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}
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127 
/// Path → (size, mtime in nanoseconds, BLAKE3 hex) as last seen.
128 
/// One manifest entry: the file's stat, its content hash, and the stored
129 
/// blob for an opaque file.
130 
#[derive(Clone, Debug)]
131 
pub(crate) struct ManifestEntry {
132 
    pub size: u64,
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    pub mtime_ns: u128,
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    pub hash: [u8; 32],
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    pub blob: Option<ObjectRef>,
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    /// The graph key (`State::graph_key`) of the base file this text file
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    /// was found equal to, rendered, byte for byte.
138 
    pub graph: Option<[u8; 32]>,
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    /// Whether the file was executable: a mode change alters neither size
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    /// nor time.
141 
    pub exec: bool,
142 
}
143
144 
#[derive(Clone, Debug, Default)]
145 
pub(crate) struct Manifest {
146 
    /// When the manifest was written, for the racy-stat guard.
147 
    pub written_ns: u128,
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    pub entries: BTreeMap<String, ManifestEntry>,
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    /// Every directory the walk listed, with its time then; empty when the
150 
    /// manifest was not written from a walk (a checkout), and then the
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    /// check lists the tree.
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    pub dirs: Vec<(String, u128)>,
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    /// Directories holding a repository of their own, as the walk found.
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    pub nested: Vec<String>,
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}
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/// A parsed manifest and the identity (size, time, inode) of the file it
158 
/// came from: reused while the file is the same one.
159 
pub(crate) type CachedManifest = ((u64, u128, u64), (bool, bool, std::sync::Arc<Manifest>));
160
161 
/// Now, in nanoseconds since the epoch.
162 
pub(crate) fn now_ns() -> u128 {
163 
    std::time::SystemTime::now()
164 
        .duration_since(UNIX_EPOCH)
165 
        .map(|d| d.as_nanos())
166 
        .unwrap_or(0)
167 
}
168
169 
pub(crate) fn mtime_ns(m: &fs::Metadata) -> u128 {
170 
    m.modified()
171 
        .ok()
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        .and_then(|t| t.duration_since(UNIX_EPOCH).ok())
173 
        .map(|d| d.as_nanos())
174 
        .unwrap_or(0)
175 
}
176
177 
pub const DEFAULT_PROMPT_FORMAT: &str = "%b %c%d%x%A%D";
178 
/// The repository icon for `%i` (an atom, for oxygen).
179 
pub const ICON: &str = "⚛";
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/// A format with glyphs: icon, bookmark, change id, state, ahead/behind.
181 
pub const GLYPH_PROMPT_FORMAT: &str = "%i %b %c %s%U%O";
182
183 
/// The manifest file (oxygen#41): a flat binary layout read in one pass.
184 
/// A magic number; the conflicted and uncommitted flags; when it was
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/// written, at a fixed offset so an otherwise equal manifest can be
186 
/// recognised; BLAKE3 of everything else; then each entry in path order:
187 
/// path, size, mtime in nanoseconds, BLAKE3 of the content, the stored
188 
/// blob of an opaque file, the graph key it was found equal to, and
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/// whether it is executable. Format 3 puts before the entries every
190 
/// directory the walk listed with its time, and the nested repositories. A file that does not check, or in any other
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/// layout (an older manifest), reads as no manifest, and the next snapshot
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/// writes it again: it is a cache, written without waiting for the disk.
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const MANIFEST_MAGIC: &[u8; 8] = b"oxyman3\0";
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/// Where the written time sits: after the magic and the two flags.
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const MANIFEST_WRITTEN: std::ops::Range<usize> = 10..26;
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/// Where the checksum sits, after the written time.
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const MANIFEST_SUM: std::ops::Range<usize> = 26..58;
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199 
fn manifest_sum(buf: &[u8]) -> [u8; 32] {
200 
    let mut h = blake3::Hasher::new();
201 
    h.update(&buf[..MANIFEST_SUM.start]);
202 
    h.update_rayon(&buf[MANIFEST_SUM.end..]);
203 
    *h.finalize().as_bytes()
204 
}
205
206 
fn encode_manifest(
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    conflicted: bool,
208 
    uncommitted: bool,
209 
    written_ns: u128,
210 
    dirs: &[(String, u128)],
211 
    nested: &[String],
212 
    entries: &mut dyn Iterator<Item = (&str, ManifestEntry)>,
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) -> Vec<u8> {
214 
    let mut w = crate::flat::Writer::default();
215 
    w.fixed(MANIFEST_MAGIC);
216 
    w.u8(conflicted as u8);
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    w.u8(uncommitted as u8);
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    w.fixed(&written_ns.to_le_bytes());
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    w.fixed(&[0; 32]);
220 
    w.count(dirs.len());
221 
    for (d, t) in dirs {
222 
        w.bytes(d.as_bytes());
223 
        w.fixed(&t.to_le_bytes());
224 
    }
225 
    w.count(nested.len());
226 
    for n in nested {
227 
        w.bytes(n.as_bytes());
228 
    }
229 
    for (path, e) in entries {
230 
        w.bytes(path.as_bytes());
231 
        w.u64(e.size);
232 
        w.fixed(&e.mtime_ns.to_le_bytes());
233 
        w.fixed(&e.hash);
234 
        w.opt_object(&e.blob);
235 
        match e.graph {
236 
            None => w.u8(0),
237 
            Some(k) => {
238 
                w.u8(1);
239 
                w.fixed(&k);
240 
            }
241 
        }
242 
        w.u8(e.exec as u8);
243 
    }
244 
    let sum = manifest_sum(&w.0);
245 
    w.0[MANIFEST_SUM].copy_from_slice(&sum);
246 
    w.0
247 
}
248
249 
fn decode_manifest(buf: &[u8]) -> Option<(bool, bool, Manifest)> {
250 
    let mut r = crate::flat::Reader::new(buf);
251 
    if &r.fixed::<8>().ok()? != MANIFEST_MAGIC {
252 
        return None;
253 
    }
254 
    let conflicted = r.u8().ok()? == 1;
255 
    let uncommitted = r.u8().ok()? == 1;
256 
    let written_ns = u128::from_le_bytes(r.fixed().ok()?);
257 
    if r.fixed::<32>().ok()? != manifest_sum(buf) {
258 
        return None;
259 
    }
260 
    let mut dirs = Vec::new();
261 
    for _ in 0..r.count().ok()? {
262 
        let d = std::str::from_utf8(r.bytes().ok()?).ok()?.to_string();
263 
        dirs.push((d, u128::from_le_bytes(r.fixed().ok()?)));
264 
    }
265 
    let mut nested = Vec::new();
266 
    for _ in 0..r.count().ok()? {
267 
        nested.push(std::str::from_utf8(r.bytes().ok()?).ok()?.to_string());
268 
    }
269 
    let mut entries = Vec::new();
270 
    while !r.at_end() {
271 
        let path = std::str::from_utf8(r.bytes().ok()?).ok()?.to_string();
272 
        let e = ManifestEntry {
273 
            size: r.u64().ok()?,
274 
            mtime_ns: u128::from_le_bytes(r.fixed().ok()?),
275 
            hash: r.fixed().ok()?,
276 
            blob: r.opt_object().ok()?,
277 
            graph: match r.u8().ok()? {
278 
                0 => None,
279 
                _ => Some(r.fixed().ok()?),
280 
            },
281 
            exec: r.u8().ok()? == 1,
282 
        };
283 
        entries.push((path, e));
284 
    }
285 
    // Written in path order, so this builds the map without searching.
286 
    let entries = entries.into_iter().collect();
287 
    Some((
288 
        conflicted,
289 
        uncommitted,
290 
        Manifest {
291 
            written_ns,
292 
            entries,
293 
            dirs,
294 
            nested,
295 
        },
296 
    ))
297 
}
298
299 
/// A tracked path as it is now: a file's stat, or a symlink's target.
300 
enum Tracked {
301 
    File(super::walk::Stat),
302 
    Link(Vec<u8>),
303 
}
304
305 
/// The stat of every path in `rels` (relative to `root`; `None` for one
306 
/// gone or neither a file nor a symlink), in the same order. Paths are
307 
/// grouped by directory and each directory is opened once: a stat relative
308 
/// to it resolves one name, where a stat by full path walks every
309 
/// component from the root again (most of a clean status's time, in the
310 
/// kernel's path lookup, on the Linux tree).
311 
fn stat_tracked(root: &Path, rels: &[&String]) -> Vec<Option<Tracked>> {
312 
    use rayon::prelude::*;
313 
    let mut by_dir: HashMap<&str, Vec<(usize, &str)>> = HashMap::new();
314 
    for (i, rel) in rels.iter().enumerate() {
315 
        let (dir, name) = rel.rsplit_once('/').unwrap_or(("", rel.as_str()));
316 
        by_dir.entry(dir).or_default().push((i, name));
317 
    }
318 
    let groups: Vec<(&str, Vec<(usize, &str)>)> = by_dir.into_iter().collect();
319 
    let found: Vec<(usize, Option<Tracked>)> = groups
320 
        .par_iter()
321 
        .flat_map_iter(|(dir, names)| {
322 
            let handle = fs::File::open(root.join(dir)).ok();
323 
            names
324 
                .iter()
325 
                .map(|(i, name)| {
326 
                    let rel = rels[*i];
327 
                    let now = match &handle {
328 
                        Some(d) => stat_in(d, name, || root.join(rel)),
329 
                        None => None,
330 
                    };
331 
                    (*i, now)
332 
                })
333 
                .collect::<Vec<_>>()
334 
        })
335 
        .collect();
336 
    let mut out: Vec<Option<Tracked>> = (0..rels.len()).map(|_| None).collect();
337 
    for (i, now) in found {
338 
        out[i] = now;
339 
    }
340 
    out
341 
}
342
343 
/// One entry of the open directory `dir`; `path` builds its full path,
344 
/// needed only for a symlink's target.
345 
#[cfg(unix)]
346 
fn stat_in(dir: &fs::File, name: &str, path: impl Fn() -> PathBuf) -> Option<Tracked> {
347 
    use std::os::fd::AsRawFd;
348 
    let c = std::ffi::CString::new(name).ok()?;
349 
    let mut st: libc::stat = unsafe { std::mem::zeroed() };
350 
    // SAFETY: a valid directory descriptor, a NUL-terminated name, and a
351 
    // stat buffer of the right type that outlives the call.
352 
    let r = unsafe {
353 
        libc::fstatat(
354 
            dir.as_raw_fd(),
355 
            c.as_ptr(),
356 
            &mut st,
357 
            libc::AT_SYMLINK_NOFOLLOW,
358 
        )
359 
    };
360 
    if r != 0 {
361 
        return None;
362 
    }
363 
    match st.st_mode & libc::S_IFMT {
364 
        libc::S_IFREG => Some(Tracked::File(super::walk::Stat {
365 
            size: st.st_size as u64,
366 
            // As `mtime_ns` reads it: nanoseconds since the epoch, 0 before it.
367 
            mtime_ns: if st.st_mtime < 0 {
368 
                0
369 
            } else {
370 
                st.st_mtime as u128 * 1_000_000_000 + st.st_mtime_nsec as u128
371 
            },
372 
            exec: st.st_mode & 0o111 != 0,
373 
        })),
374 
        libc::S_IFLNK => {
375 
            let t = fs::read_link(path()).ok()?;
376 
            Some(Tracked::Link(t.to_string_lossy().as_bytes().to_vec()))
377 
        }
378 
        _ => None,
379 
    }
380 
}
381
382 
#[cfg(not(unix))]
383 
fn stat_in(_dir: &fs::File, _name: &str, path: impl Fn() -> PathBuf) -> Option<Tracked> {
384 
    let p = path();
385 
    let m = fs::symlink_metadata(&p).ok()?;
386 
    if m.file_type().is_symlink() {
387 
        let t = fs::read_link(&p).ok()?;
388 
        Some(Tracked::Link(t.to_string_lossy().as_bytes().to_vec()))
389 
    } else if m.is_file() {
390 
        Some(Tracked::File(super::walk::Stat::of(&m)))
391 
    } else {
392 
        None
393 
    }
394 
}
395
396 
/// The status cache: a magic number, the working-copy change, the
397 
/// manifest checksum, then each status line (a status byte and a path).
398 
const STATUS_MAGIC: &[u8; 8] = b"oxystat1";
399
400 
fn status_byte(s: ChangeStatus) -> u8 {
401 
    match s {
402 
        ChangeStatus::Added => 0,
403 
        ChangeStatus::Modified => 1,
404 
        ChangeStatus::Removed => 2,
405 
        ChangeStatus::Renamed => 3,
406 
        ChangeStatus::ModeChanged => 4,
407 
        ChangeStatus::ConflictEdited => 5,
408 
        ChangeStatus::Resolved => 6,
409 
    }
410 
}
411
412 
fn encode_status_cache(wc: &ChangeHash, stamp: &[u8; 32], statuses: &[PathStatus]) -> Vec<u8> {
413 
    let mut out = Vec::with_capacity(80 + statuses.len() * 40);
414 
    out.extend_from_slice(STATUS_MAGIC);
415 
    out.extend_from_slice(&wc.0);
416 
    out.extend_from_slice(stamp);
417 
    out.extend_from_slice(&(statuses.len() as u32).to_le_bytes());
418 
    for s in statuses {
419 
        out.push(status_byte(s.status));
420 
        out.extend_from_slice(&(s.path.len() as u32).to_le_bytes());
421 
        out.extend_from_slice(s.path.as_bytes());
422 
    }
423 
    out
424 
}
425
426 
fn decode_status_cache(b: &[u8]) -> Option<(ChangeHash, [u8; 32], Vec<PathStatus>)> {
427 
    let rest = b.strip_prefix(STATUS_MAGIC)?;
428 
    let wc = ObjectRef(rest.get(..32)?.try_into().ok()?);
429 
    let stamp: [u8; 32] = rest.get(32..64)?.try_into().ok()?;
430 
    let n = u32::from_le_bytes(rest.get(64..68)?.try_into().ok()?) as usize;
431 
    let mut at = 68;
432 
    let mut out = Vec::with_capacity(n.min(1 << 16));
433 
    for _ in 0..n {
434 
        let status = match *rest.get(at)? {
435 
            0 => ChangeStatus::Added,
436 
            1 => ChangeStatus::Modified,
437 
            2 => ChangeStatus::Removed,
438 
            3 => ChangeStatus::Renamed,
439 
            4 => ChangeStatus::ModeChanged,
440 
            5 => ChangeStatus::ConflictEdited,
441 
            6 => ChangeStatus::Resolved,
442 
            _ => return None,
443 
        };
444 
        let len = u32::from_le_bytes(rest.get(at + 1..at + 5)?.try_into().ok()?) as usize;
445 
        let path = std::str::from_utf8(rest.get(at + 5..at + 5 + len)?)
446 
            .ok()?
447 
            .to_string();
448 
        out.push(PathStatus { path, status });
449 
        at += 5 + len;
450 
    }
451 
    (at == rest.len()).then_some((wc, stamp, out))
452 
}
453
454 
impl Repo {
455 
    pub(crate) fn manifest_path(&self) -> PathBuf {
456 
        self.oxy
457 
            .join("workspaces")
458 
            .join(self.workspace.to_hex())
459 
            .join("manifest")
460 
    }
461
462 
    /// Record the working copy as it is now (after a snapshot, commit, or
463 
    /// checkout), with header lines saying whether the base state is
464 
    /// conflicted and whether the working-copy change holds uncommitted work.
465 
    pub(crate) fn write_manifest(&self, conflicted: bool, uncommitted: bool) -> Result<()> {
466 
        let entries = self.walk_working_copy()?;
467 
        self.write_manifest_entries(conflicted, uncommitted, &entries, &HashMap::new())
468 
    }
469
470 
    /// Write the manifest from entries already walked; `blobs` names the
471 
    /// stored blob of each opaque path so the next walk can skip reading it.
472 
    pub(crate) fn write_manifest_entries(
473 
        &self,
474 
        conflicted: bool,
475 
        uncommitted: bool,
476 
        entries: &BTreeMap<String, FsEntry>,
477 
        blobs: &HashMap<String, ObjectRef>,
478 
    ) -> Result<()> {
479 
        let dirs = self.walked_dirs.take().unwrap_or_default();
480 
        self.write_manifest_entries_as_of(conflicted, uncommitted, entries, blobs, now_ns(), dirs)
481 
    }
482
483 
    /// `write_manifest_entries` stamped `written` (when the entries were
484 
    /// read), with the directories of the walk they came from.
485 
    pub(crate) fn write_manifest_entries_as_of(
486 
        &self,
487 
        conflicted: bool,
488 
        uncommitted: bool,
489 
        entries: &BTreeMap<String, FsEntry>,
490 
        blobs: &HashMap<String, ObjectRef>,
491 
        written: u128,
492 
        (dirs, nested): WalkedDirs,
493 
    ) -> Result<()> {
494 
        self.manifest_cache.take();
495 
        self.listing_cache.take();
496 
        let mut newest_ns: u128 = 0;
497 
        let mut rows = entries.iter().map(|(path, e)| {
498 
            let (size, mtime_ns) = match e.stat {
499 
                Some(known) => known,
500 
                None => match fs::symlink_metadata(self.root.join(path)) {
501 
                    Ok(m) => (m.len(), mtime_ns(&m)),
502 
                    Err(_) => (e.content.len() as u64, 0),
503 
                },
504 
            };
505 
            newest_ns = newest_ns.max(mtime_ns);
506 
            let entry = ManifestEntry {
507 
                size,
508 
                mtime_ns,
509 
                hash: e
510 
                    .content_hash
511 
                    .unwrap_or_else(|| *blake3::hash(&e.content).as_bytes()),
512 
                blob: blobs.get(path).copied().or(e.blob),
513 
                graph: e.graph_key,
514 
                exec: e.exec,
515 
            };
516 
            (path.as_str(), entry)
517 
        });
518 
        let new = encode_manifest(conflicted, uncommitted, written, &dirs, &nested, &mut rows);
519 
        drop(rows);
520 
        let p = self.manifest_path();
521 
        // Leave an unchanged manifest alone when its stamp already trusts
522 
        // every entry (none is within the racy window): rewriting it would
523 
        // change nothing but the file, which editors watching the tree
524 
        // (and subrepos inside it) take as a change.
525 
        if let Ok(old) = fs::read(&p) {
526 
            let (w, sum) = (MANIFEST_WRITTEN, MANIFEST_SUM);
527 
            if old.len() == new.len()
528 
                && old[..w.start] == new[..w.start]
529 
                && old[sum.end..] == new[sum.end..]
530 
            {
531 
                let old_written = u128::from_le_bytes(old[w.clone()].try_into().unwrap());
532 
                if newest_ns + 2_000_000_000 < old_written {
533 
                    return Ok(());
534 
                }
535 
            }
536 
        }
537 
        fs::create_dir_all(p.parent().unwrap())?;
538 
        write_cache(&p, &new)
539 
    }
540
541 
    /// Change the header flags, and set the graph key of each path in
542 
    /// `keys` (after a commit, the new base's keys of the files it holds as
543 
    /// they are on disk).
544 
    pub(crate) fn rewrite_manifest(
545 
        &self,
546 
        conflicted: bool,
547 
        uncommitted: bool,
548 
        keys: &HashMap<String, [u8; 32]>,
549 
    ) -> Result<()> {
550 
        self.manifest_cache.take();
551 
        self.listing_cache.take();
552 
        let p = self.manifest_path();
553 
        let Some((_, _, m)) = fs::read(&p).ok().and_then(|b| decode_manifest(&b)) else {
554 
            return self.write_manifest(conflicted, uncommitted);
555 
        };
556 
        let mut rows = m.entries.iter().map(|(path, e)| {
557 
            let mut e = e.clone();
558 
            if let Some(k) = keys.get(path) {
559 
                e.graph = Some(*k);
560 
            }
561 
            (path.as_str(), e)
562 
        });
563 
        write_cache(
564 
            &p,
565 
            &encode_manifest(
566 
                conflicted,
567 
                uncommitted,
568 
                m.written_ns,
569 
                &m.dirs,
570 
                &m.nested,
571 
                &mut rows,
572 
            ),
573 
        )
574 
    }
575
576 
    /// Forget the manifest after an operation that changed the working-copy
577 
    /// change without a snapshot (undo, rewrites); the prompt shows blank
578 
    /// markers until the next snapshot.
579 
    pub(crate) fn drop_manifest(&self) {
580 
        self.manifest_cache.take();
581 
        self.listing_cache.take();
582 
        let _ = fs::remove_file(self.manifest_path());
583 
    }
584
585 
    /// The manifest, with whether it records a conflict and uncommitted
586 
    /// work; parsed once while the file stays the same one.
587 
    /// Whether the working copy was conflicted when last recorded (the
588 
    /// manifest's flag), without looking at the files.
589 
    pub fn recorded_conflicted(&self) -> Result<bool> {
590 
        Ok(self.read_manifest()?.is_some_and(|(c, _, _)| c))
591 
    }
592
593 
    pub(crate) fn read_manifest(&self) -> Result<Option<(bool, bool, std::sync::Arc<Manifest>)>> {
594 
        let path = self.manifest_path();
595 
        let id = match fs::metadata(&path) {
596 
            Ok(m) => {
597 
                #[cfg(unix)]
598 
                let ino = std::os::unix::fs::MetadataExt::ino(&m);
599 
                #[cfg(not(unix))]
600 
                let ino = 0;
601 
                (m.len(), mtime_ns(&m), ino)
602 
            }
603 
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(None),
604 
            Err(e) => return Err(e.into()),
605 
        };
606 
        if let Some((cached_id, m)) = &*self.manifest_cache.borrow() {
607 
            if *cached_id == id {
608 
                return Ok(Some(m.clone()));
609 
            }
610 
        }
611 
        let Some((c, u, m)) = self.parse_manifest(&path)? else {
612 
            return Ok(None);
613 
        };
614 
        let m = (c, u, std::sync::Arc::new(m));
615 
        *self.manifest_cache.borrow_mut() = Some((id, m.clone()));
616 
        Ok(Some(m))
617 
    }
618
619 
    fn parse_manifest(&self, path: &std::path::Path) -> Result<Option<(bool, bool, Manifest)>> {
620 
        let buf = match fs::read(path) {
621 
            Ok(b) => b,
622 
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(None),
623 
            Err(e) => return Err(e.into()),
624 
        };
625 
        Ok(decode_manifest(&buf))
626 
    }
627
628 
    /// Whether the working copy is certainly clean, known from the manifest
629 
    /// alone, without loading any history (spec §12.4): the last snapshot
630 
    /// or commit found no uncommitted work and no conflict, there are no
631 
    /// subrepos (whose state the manifest does not hold), and no file was
632 
    /// added, removed or changed since. An entry inside the racy window,
633 
    /// where an equal size and time do not prove equal content, is checked
634 
    /// by hashing the file. `false` means only that a snapshot must decide.
635 
    pub fn clean_by_manifest(&self) -> Result<bool> {
636 
        let _t = crate::timing::phase("status: check the manifest");
637 
        // Why a snapshot must decide, with timings on.
638 
        let not = |why: &str| {
639 
            if crate::timing::enabled() {
640 
                eprintln!("timing status: not clean by the manifest: {why}");
641 
            }
642 
            Ok(false)
643 
        };
644 
        let Some((conflicted, uncommitted, m)) = self.read_manifest()? else {
645 
            return not("no manifest");
646 
        };
647 
        if conflicted || uncommitted || self.root.join(".oxymodules").exists() {
648 
            return not("conflicted, uncommitted or subrepos");
649 
        }
650 
        let started = now_ns();
651 
        if self.disk_differs(&m, true)? {
652 
            return not("a file differs");
653 
        }
654 
        // Verified clean. Entries or directories within the racy window of
655 
        // the manifest's time were hashed or listed just now; restamped with
656 
        // the time this check began, the next check can trust them, as
657 
        // Git restamps its index (anything changed within two seconds of
658 
        // that time is still racy by the same rule).
659 
        // A check that had to list the tree leaves the directories it
660 
        // listed: kept, the next check need not list.
661 
        let window = 2_000_000_000;
662 
        let listed = self.listed_dirs.take();
663 
        let racy = m.dirs.iter().any(|(_, t)| t + window >= m.written_ns)
664 
            || m.entries
665 
                .values()
666 
                .any(|e| e.mtime_ns + window >= m.written_ns);
667 
        if (racy || (m.dirs.is_empty() && listed.is_some())) && started > m.written_ns {
668 
            let (dirs, nested) = listed.unwrap_or_else(|| (m.dirs.clone(), m.nested.clone()));
669 
            self.restamp_manifest(&m, conflicted, uncommitted, started, &dirs, &nested);
670 
        }
671 
        Ok(true)
672 
    }
673
674 
    /// Rewrite the manifest with a new time and directory list, its entries
675 
    /// unchanged.
676 
    fn restamp_manifest(
677 
        &self,
678 
        m: &Manifest,
679 
        conflicted: bool,
680 
        uncommitted: bool,
681 
        written_ns: u128,
682 
        dirs: &[(String, u128)],
683 
        nested: &[String],
684 
    ) {
685 
        let _t = crate::timing::phase("status: restamp the manifest");
686 
        let mut rows = m.entries.iter().map(|(p, e)| (p.as_str(), e.clone()));
687 
        let bytes = encode_manifest(conflicted, uncommitted, written_ns, dirs, nested, &mut rows);
688 
        self.manifest_cache.take();
689 
        let _ = write_cache(&self.manifest_path(), &bytes);
690 
    }
691
692 
    /// A manifest entry written within the racy window whose file no
693 
    /// longer matches it. Such entries are hashed, in parallel (a checkout
694 
    /// just wrote them all).
695 
    fn racy_change(&self, m: &Manifest) -> Option<String> {
696 
        use rayon::prelude::*;
697 
        let racy: Vec<(&String, &ManifestEntry)> = m
698 
            .entries
699 
            .iter()
700 
            .filter(|(_, e)| e.mtime_ns + 2_000_000_000 >= m.written_ns)
701 
            .collect();
702 
        let root = &self.root;
703 
        racy.par_iter()
704 
            .find_any(|(rel, e)| {
705 
                let path = root.join(rel.as_str());
706 
                let same = match fs::symlink_metadata(&path) {
707 
                    Ok(md) if md.file_type().is_symlink() => fs::read_link(&path).is_ok_and(|t| {
708 
                        *blake3::hash(t.to_string_lossy().as_bytes()).as_bytes() == e.hash
709 
                    }),
710 
                    Ok(md) if md.is_file() => {
711 
                        md.len() == e.size
712 
                            && fs::read(&path).is_ok_and(|b| *blake3::hash(&b).as_bytes() == e.hash)
713 
                    }
714 
                    _ => false,
715 
                };
716 
                !same
717 
            })
718 
            .map(|(rel, _)| rel.to_string())
719 
    }
720
721 
    /// The status lines of the last snapshot, when the working copy is as
722 
    /// that snapshot left it: the cache it wrote names the working-copy
723 
    /// change and the manifest it recorded, and every file still matches
724 
    /// that manifest. `None` when a snapshot must decide (no cache, a file
725 
    /// changed, conflicts or subrepos). An empty list is a clean working
726 
    /// copy.
727 
    pub fn status_by_manifest(&self) -> Result<Option<Vec<PathStatus>>> {
728 
        // A listing left by an earlier check describes the files as they
729 
        // were then; this check makes its own.
730 
        self.listing_cache.take();
731 
        let Some((conflicted, uncommitted, m)) = self.read_manifest()? else {
732 
            return Ok(None);
733 
        };
734 
        if !uncommitted {
735 
            return Ok(self.clean_by_manifest()?.then(Vec::new));
736 
        }
737 
        let _t = crate::timing::phase("status: by the status cache");
738 
        if conflicted || self.root.join(".oxymodules").exists() {
739 
            return Ok(None);
740 
        }
741 
        let Some((wc, stamp, statuses)) = fs::read(self.status_cache_path())
742 
            .ok()
743 
            .and_then(|b| decode_status_cache(&b))
744 
        else {
745 
            return Ok(None);
746 
        };
747 
        let now = self.view()?.workspaces.get(&self.workspace).copied();
748 
        if now != Some(wc) || self.manifest_stamp() != Some(stamp) {
749 
            return Ok(None);
750 
        }
751 
        if self.disk_differs(&m, true)? {
752 
            return Ok(None);
753 
        }
754 
        // Test builds check the cache against a snapshot of the files.
755 
        #[cfg(test)]
756 
        {
757 
            let snap = self.snapshot_status("status cache check")?;
758 
            let key = |v: &[PathStatus]| {
759 
                let mut k: Vec<(String, u8)> = v
760 
                    .iter()
761 
                    .map(|p| (p.path.clone(), status_byte(p.status)))
762 
                    .collect();
763 
                k.sort();
764 
                k
765 
            };
766 
            assert_eq!(
767 
                key(&statuses),
768 
                key(&snap.statuses),
769 
                "status cache disagrees with a snapshot"
770 
            );
771 
        }
772 
        Ok(Some(statuses))
773 
    }
774
775 
    fn status_cache_path(&self) -> PathBuf {
776 
        self.manifest_path().with_file_name("status")
777 
    }
778
779 
    /// The manifest file's checksum, which names its content.
780 
    fn manifest_stamp(&self) -> Option<[u8; 32]> {
781 
        use std::io::Read;
782 
        let mut head = [0u8; MANIFEST_SUM.end];
783 
        fs::File::open(self.manifest_path())
784 
            .and_then(|mut f| f.read_exact(&mut head))
785 
            .ok()?;
786 
        head[MANIFEST_SUM].try_into().ok()
787 
    }
788
789 
    /// Record `statuses` as the status of working-copy change `wc` against
790 
    /// the manifest as it is now; with no uncommitted work there is nothing
791 
    /// to record, and the cache goes.
792 
    pub(crate) fn write_status_cache(&self, wc: Option<&ChangeHash>, statuses: &[PathStatus]) {
793 
        let path = self.status_cache_path();
794 
        let (Some(wc), Some(stamp)) = (wc, self.manifest_stamp()) else {
795 
            let _ = fs::remove_file(&path);
796 
            return;
797 
        };
798 
        let _ = write_cache(&path, &encode_status_cache(wc, &stamp, statuses));
799 
    }
800
801 
    /// Whether the working copy differs from the last manifest. Without a
802 
    /// manifest the answer is `None`.
803 
    pub fn quick_dirty(&self) -> Result<Option<bool>> {
804 
        self.quick_dirty_keeping(false)
805 
    }
806
807 
    /// `quick_dirty`; with `keep`, the listing it made is left for the
808 
    /// next walk of the working copy.
809 
    fn quick_dirty_keeping(&self, keep: bool) -> Result<Option<bool>> {
810 
        let Some((_, uncommitted, manifest)) = self.read_manifest()? else {
811 
            return Ok(None);
812 
        };
813 
        if uncommitted {
814 
            return Ok(Some(true));
815 
        }
816 
        Ok(Some(self.disk_differs(&manifest, keep)?))
817 
    }
818
819 
    /// Whether the working copy differs from `manifest`: a file added,
820 
    /// gone or changed. With `keep`, the listing made is left for the next
821 
    /// walk of the working copy when it does.
822 
    fn disk_differs(&self, manifest: &Manifest, keep: bool) -> Result<bool> {
823 
        // A file written within the racy window can change without its size
824 
        // or time moving (a coarse clock): those entries are hashed. One
825 
        // that changed still lets the directory check below hand its stats
826 
        // to the snapshot that follows.
827 
        let racy = self.racy_change(manifest).is_some();
828 
        if let Some(differs) = self.disk_differs_by_dirs_keeping(manifest, keep, racy) {
829 
            return Ok(differs || racy);
830 
        }
831 
        if racy {
832 
            return Ok(true);
833 
        }
834 
        self.disk_differs_listing(manifest, keep)
835 
    }
836
837 
    /// [`Repo::disk_differs`] without listing the tree, when the manifest
838 
    /// knows its directories: a directory's time moves when an entry is
839 
    /// added, removed or renamed in it, so with every directory's time as
840 
    /// recorded (and none within the racy window) the files are the
841 
    /// manifest's, and each is checked by its stat. `None` when a
842 
    /// directory changed or the manifest has none: the tree must be listed.
843 
    #[cfg(test)]
844 
    pub(crate) fn disk_differs_by_dirs(&self, manifest: &Manifest) -> Option<bool> {
845 
        self.disk_differs_by_dirs_keeping(manifest, false, false)
846 
    }
847
848 
    /// [`Repo::disk_differs_by_dirs`]; with `keep`, when a file differs
849 
    /// (or `racy` says one does), the stats taken become the listing of the
850 
    /// snapshot that follows: no directory's entries changed, so the
851 
    /// manifest's files are the tree's.
852 
    fn disk_differs_by_dirs_keeping(
853 
        &self,
854 
        manifest: &Manifest,
855 
        keep: bool,
856 
        racy: bool,
857 
    ) -> Option<bool> {
858 
        use rayon::prelude::*;
859 
        if manifest.dirs.is_empty() || !self.config.sparse_paths.is_empty() {
860 
            return None;
861 
        }
862 
        let _t = crate::timing::phase("status: directories and files by stat");
863 
        let root = &self.root;
864 
        let dirs_same = manifest.dirs.par_iter().all(|(rel, t)| {
865 
            *t + 2_000_000_000 < manifest.written_ns
866 
                && fs::metadata(root.join(rel)).is_ok_and(|m| m.is_dir() && mtime_ns(&m) == *t)
867 
        });
868 
        if !dirs_same {
869 
            return None;
870 
        }
871 
        let rels: Vec<&String> = manifest.entries.keys().collect();
872 
        let now = stat_tracked(root, &rels);
873 
        let differs_from = |me: &ManifestEntry, rel: &str, now: &Tracked| match now {
874 
            Tracked::Link(t) => *blake3::hash(t).as_bytes() != me.hash,
875 
            Tracked::File(m) => {
876 
                m.size != me.size
877 
                    || m.exec != me.exec
878 
                    || (m.mtime_ns != me.mtime_ns
879 
                        && !fs::read(root.join(rel))
880 
                            .is_ok_and(|b| *blake3::hash(&b).as_bytes() == me.hash))
881 
            }
882 
        };
883 
        // A path gone or no longer a file: its directory moved, unless
884 
        // within a clock tick; list the tree to be sure.
885 
        if now.iter().any(Option::is_none) {
886 
            return None;
887 
        }
888 
        // The entries in the order `rels` was taken in: no lookup by path.
889 
        let entries: Vec<&ManifestEntry> = manifest.entries.values().collect();
890 
        let differs = rels
891 
            .par_iter()
892 
            .zip(entries.par_iter())
893 
            .zip(now.par_iter())
894 
            .any(|((rel, me), n)| differs_from(me, rel, n.as_ref().unwrap()));
895 
        if keep && (differs || racy) {
896 
            let mut listing = super::walk::Listing {
897 
                dirs: manifest.dirs.clone(),
898 
                nested: manifest.nested.iter().map(|n| root.join(n)).collect(),
899 
                ..Default::default()
900 
            };
901 
            for (rel, n) in rels.into_iter().zip(now) {
902 
                match n.unwrap() {
903 
                    Tracked::File(m) => listing.files.push((rel.clone(), root.join(rel), m)),
904 
                    Tracked::Link(t) => listing.symlinks.push((rel.clone(), t)),
905 
                }
906 
            }
907 
            *self.listing_cache.borrow_mut() = Some(listing);
908 
        }
909 
        if !differs {
910 
            // Nested repositories the manifest has no entry for are not
911 
            // subrepos: nothing in them is tracked (oxygen#43).
912 
            *self.untracked_nested.borrow_mut() = manifest
913 
                .nested
914 
                .iter()
915 
                .filter(|rel| !manifest.entries.contains_key(*rel))
916 
                .cloned()
917 
                .collect();
918 
        }
919 
        Some(differs)
920 
    }
921
922 
    /// [`Repo::disk_differs`] by listing the tree.
923 
    fn disk_differs_listing(&self, manifest: &Manifest, keep: bool) -> Result<bool> {
924 
        use rayon::prelude::*;
925 
        let sparse = &self.config.sparse_paths;
926 
        let in_scope = |p: &str| {
927 
            sparse.is_empty()
928 
                || sparse
929 
                    .iter()
930 
                    .any(|s| p == s || p.starts_with(&format!("{s}/")))
931 
        };
932 
        // A working copy that cannot be listed counts as changed.
933 
        // Known files are not matched against the ignore rules: with no
934 
        // uncommitted work (the clean check), the manifest's files are the
935 
        // base's, and a prompt's answer is the same either way.
936 
        let known = |p: &str| manifest.entries.contains_key(p);
937 
        let Ok(listing) = super::walk::list_knowing(&self.root, &in_scope, &known) else {
938 
            return Ok(true);
939 
        };
940 
        let differs = || -> Result<bool> {
941 
            let links_differ = listing.symlinks.iter().any(|(rel, target)| {
942 
                manifest
943 
                    .entries
944 
                    .get(rel)
945 
                    .is_none_or(|me| *blake3::hash(target).as_bytes() != me.hash)
946 
            });
947 
            if links_differ {
948 
                return Ok(true);
949 
            }
950 
            // Each file is checked on its own, in parallel, stopping at the
951 
            // first difference; an unreadable one counts as different.
952 
            let files_differ = listing.files.par_iter().any(|(rel, path, m)| {
953 
                manifest.entries.get(rel).is_none_or(|me| {
954 
                    m.size != me.size
955 
                        || m.exec != me.exec
956 
                        || (m.mtime_ns != me.mtime_ns
957 
                            && !fs::read(path)
958 
                                .is_ok_and(|b| *blake3::hash(&b).as_bytes() == me.hash))
959 
                })
960 
            });
961 
            if files_differ {
962 
                return Ok(true);
963 
            }
964 
            let seen = listing.files.len() + listing.symlinks.len();
965 
            if seen == manifest.entries.len() {
966 
                return Ok(false);
967 
            }
968 
            // Manifest entries the walk skipped: tracked files that ignore
969 
            // rules hide (Linux tracks some its own .gitignore names). Found
970 
            // by merging the two sorted lists; they count as present when
971 
            // still on disk and unchanged, checked on every core.
972 
            let mut listed: Vec<&str> = listing
973 
                .files
974 
                .iter()
975 
                .map(|(r, _, _)| r.as_str())
976 
                .chain(listing.symlinks.iter().map(|(r, _)| r.as_str()))
977 
                .collect();
978 
            listed.sort_unstable();
979 
            let mut at = listed.iter().peekable();
980 
            let skipped: Vec<(&String, &ManifestEntry)> = manifest
981 
                .entries
982 
                .iter()
983 
                .filter(|(rel, _)| {
984 
                    while at.next_if(|l| **l < rel.as_str()).is_some() {}
985 
                    at.peek().is_none_or(|l| **l != rel.as_str())
986 
                })
987 
                .collect();
988 
            let root = &self.root;
989 
            Ok(skipped.par_iter().any(|(rel, me)| {
990 
                let path = root.join(rel.as_str());
991 
                let Ok(m) = fs::symlink_metadata(&path) else {
992 
                    return true;
993 
                };
994 
                !m.file_type().is_symlink()
995 
                    && (m.len() != me.size
996 
                        || super::is_executable(&m) != me.exec
997 
                        || (mtime_ns(&m) != me.mtime_ns
998 
                            && !fs::read(&path)
999 
                                .is_ok_and(|b| *blake3::hash(&b).as_bytes() == me.hash)))
1000 
            }))
1001 
        };
1002 
        let dirty = differs()?;
1003 
        if !dirty {
1004 
            // Nested repositories the manifest has no entry for are not
1005 
            // subrepos: nothing in them is tracked (oxygen#43).
1006 
            let mut nested: Vec<String> = listing
1007 
                .nested
1008 
                .iter()
1009 
                .map(|d| self.rel_path(d))
1010 
                .filter(|rel| !manifest.entries.contains_key(rel))
1011 
                .collect();
1012 
            nested.sort();
1013 
            *self.untracked_nested.borrow_mut() = nested;
1014 
            // A complete list of the directories, each timed before it was
1015 
            // read, for a restamp to keep (see `clean_by_manifest`).
1016 
            *self.listed_dirs.borrow_mut() = Some((
1017 
                listing.dirs.clone(),
1018 
                listing.nested.iter().map(|d| self.rel_path(d)).collect(),
1019 
            ));
1020 
        }
1021 
        if dirty && keep {
1022 
            *self.listing_cache.borrow_mut() = Some(listing);
1023 
        }
1024 
        Ok(dirty)
1025 
    }
1026
1027 
    /// Prompt information without recording anything.
1028 
    pub fn quick_status(&self) -> Result<PromptInfo> {
1029 
        let view = self.view()?;
1030 
        let bookmark = self.config.bookmark.clone();
1031 
        let heads = self.heads_of(&view, &bookmark)?;
1032 
        let wc_hash = view.workspaces.get(&self.workspace).copied();
1033 
        let change_id = match wc_hash {
1034 
            Some(h) => self.store.get_change_meta(&h)?.change_id.short(8),
1035 
            None => String::new(),
1036 
        };
1037 
        // Conflictedness was recorded by the last snapshot; without a
1038 
        // manifest (never snapshotted) both flags are unknown and shown clear.
1039 
        let manifest = self.read_manifest()?;
1040 
        let conflicted = manifest.as_ref().map(|(c, _, _)| *c).unwrap_or(false);
1041 
        let dirty = self.quick_dirty()?.unwrap_or(false);
1042 
        let (ahead, behind) = match view
1043 
            .remotes
1044 
            .get(&self.default_remote())
1045 
            .and_then(|b| b.get(&bookmark))
1046 
        {
1047 
            Some(st) => {
1048 
                let remote_heads = self.store.get_state(st)?.heads;
1049 
                let ahead = self.negotiate(&remote_heads, &heads).map(|v| v.len()).ok();
1050 
                let behind = self.negotiate(&heads, &remote_heads).map(|v| v.len()).ok();
1051 
                (ahead, behind)
1052 
            }
1053 
            None => (None, None),
1054 
        };
1055 
        Ok(PromptInfo {
1056 
            bookmark,
1057 
            change_id,
1058 
            heads: heads.len(),
1059 
            dirty,
1060 
            conflicted,
1061 
            ahead,
1062 
            behind,
1063 
        })
1064 
    }
1065 
}
1066
1067 
#[cfg(test)]
1068 
mod tests {
1069 
    use super::*;
1070
1071 
    #[test]
1072 
    fn placeholders_and_glyphs() {
1073 
        let clean = PromptInfo {
1074 
            bookmark: "main".into(),
1075 
            change_id: "658990aa".into(),
1076 
            heads: 1,
1077 
            dirty: false,
1078 
            conflicted: false,
1079 
            ahead: Some(0),
1080 
            behind: None,
1081 
        };
1082 
        assert_eq!(clean.format(DEFAULT_PROMPT_FORMAT), "main 658990aa");
1083 
        assert_eq!(clean.format(GLYPH_PROMPT_FORMAT), "⚛ main 658990aa ✔");
1084 
        let busy = PromptInfo {
1085 
            dirty: true,
1086 
            ahead: Some(2),
1087 
            behind: Some(3),
1088 
            ..clean.clone()
1089 
        };
1090 
        assert_eq!(busy.format(DEFAULT_PROMPT_FORMAT), "main 658990aa*+2-3");
1091 
        assert_eq!(busy.format(GLYPH_PROMPT_FORMAT), "⚛ main 658990aa ✎↑2↓3");
1092 
        let bad = PromptInfo {
1093 
            conflicted: true,
1094 
            ..busy.clone()
1095 
        };
1096 
        assert_eq!(bad.format("%s%x%d %h %a/%B %%"), "‼!* 1 2/3 %");
1097 
        assert_eq!(bad.state_color(), 31);
1098 
        assert_eq!(
1099 
            busy.format_colored("%b", ("\\[", "\\]")),
1100 
            "\\[\x1b[33m\\]main\\[\x1b[0m\\]"
1101 
        );
1102 
        assert_eq!(clean.format_colored("%b", ("", "")), "\x1b[36mmain\x1b[0m");
1103 
        assert_eq!(clean.format("%q"), "%q");
1104 
    }
1105 
}