OXYGENHUB
# cd4eb55e3b3d oxygen / crates / oxy-core / src / repo / prompt.rs
36.6 KiB · Rust · last changed Commit takes a status's snapshot from the cache; the stat check lends its stats to the snapshot (refs #41) 1 month ago source blame history raw
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//! Fast, side-effect-free status for shell prompts.
2 
//!
3 
//! Every snapshot and checkout writes a manifest of the working copy as it
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//! was last seen: `size`, `mtime`, and BLAKE3 of each file. `quick_status`
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//! walks the working copy and compares against that manifest, reading a
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//! file's content only when its size or mtime changed, and records no
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//! operation. Ahead/behind counts come from walking the store between the
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//! local bookmark and its `origin` tracking state.
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10 
use super::*;
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use std::time::UNIX_EPOCH;
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#[derive(Debug, Clone, Default, PartialEq, Eq)]
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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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}
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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 {
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        if self.conflicted {
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            "‼"
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        } else if self.dirty {
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            "✎"
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        } else {
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            "✔"
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        }
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    }
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    /// The ANSI colour (SGR parameter) for the state: red, yellow, or cyan.
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    pub fn state_color(&self) -> u8 {
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        if self.conflicted {
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            31
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        } else if self.dirty {
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            33
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        } else {
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            36
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        }
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    }
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    /// `format` wrapped in the state colour. `guard` is `("\\[", "\\]")` for
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    /// bash prompts, `("%{", "%}")` for zsh, or empty for raw output.
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    pub fn format_colored(&self, fmt: &str, guard: (&str, &str)) -> String {
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        format!(
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            "{}\x1b[{}m{}{}{}\x1b[0m{}",
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            guard.0,
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            self.state_color(),
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            guard.1,
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            self.format(fmt),
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            guard.0,
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            guard.1
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        )
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    }
63
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    /// Expand `%b` bookmark, `%c` change id, `%h` heads, `%d` dirty marker
65 
    /// (`*`), `%x` conflict marker (`!`), `%a`/`%B` ahead/behind counts
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    /// (empty when unknown), `%A`/`%D` `+n`/`-n` when non-zero, `%s` the
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    /// state glyph, `%U`/`%O` `↑n`/`↓n` when non-zero, `%i` the repository
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    /// icon, `%%` percent.
69 
    pub fn format(&self, fmt: &str) -> String {
70 
        let mut out = String::new();
71 
        let mut chars = fmt.chars();
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        while let Some(c) = chars.next() {
73 
            if c != '%' {
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                out.push(c);
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                continue;
76 
            }
77 
            match chars.next() {
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                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()),
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                Some('d') => {
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                    if self.dirty {
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                        out.push('*');
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                    }
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                }
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                Some('x') => {
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                    if self.conflicted {
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                        out.push('!');
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                    }
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                }
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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') => {
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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('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') => {
105 
                    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') => {
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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('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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            }
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        }
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        out
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    }
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}
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/// 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.
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    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,
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}
143
144 
#[derive(Clone, Debug, Default)]
145 
pub(crate) struct Manifest {
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    /// When the manifest was written, for the racy-stat guard.
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    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
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    /// 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
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/// 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
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pub(crate) fn mtime_ns(m: &fs::Metadata) -> u128 {
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    m.modified()
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        .ok()
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        .and_then(|t| t.duration_since(UNIX_EPOCH).ok())
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        .map(|d| d.as_nanos())
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        .unwrap_or(0)
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}
168
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pub const DEFAULT_PROMPT_FORMAT: &str = "%b %c%d%x%A%D";
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/// The repository icon for `%i` (an atom, for oxygen).
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pub const ICON: &str = "⚛";
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/// A format with glyphs: icon, bookmark, change id, state, ahead/behind.
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pub const GLYPH_PROMPT_FORMAT: &str = "%i %b %c %s%U%O";
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/// The manifest file (oxygen#41): a flat binary layout read in one pass.
176 
/// 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
178 
/// recognised; BLAKE3 of everything else; then each entry in path order:
179 
/// path, size, mtime in nanoseconds, BLAKE3 of the content, the stored
180 
/// 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
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/// 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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fn manifest_sum(buf: &[u8]) -> [u8; 32] {
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    let mut h = blake3::Hasher::new();
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    h.update(&buf[..MANIFEST_SUM.start]);
194 
    h.update_rayon(&buf[MANIFEST_SUM.end..]);
195 
    *h.finalize().as_bytes()
196 
}
197
198 
fn encode_manifest(
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    conflicted: bool,
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    uncommitted: bool,
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    written_ns: u128,
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    dirs: &[(String, u128)],
203 
    nested: &[String],
204 
    entries: &mut dyn Iterator<Item = (&str, ManifestEntry)>,
205 
) -> Vec<u8> {
206 
    let mut w = crate::flat::Writer::default();
207 
    w.fixed(MANIFEST_MAGIC);
208 
    w.u8(conflicted as u8);
209 
    w.u8(uncommitted as u8);
210 
    w.fixed(&written_ns.to_le_bytes());
211 
    w.fixed(&[0; 32]);
212 
    w.count(dirs.len());
213 
    for (d, t) in dirs {
214 
        w.bytes(d.as_bytes());
215 
        w.fixed(&t.to_le_bytes());
216 
    }
217 
    w.count(nested.len());
218 
    for n in nested {
219 
        w.bytes(n.as_bytes());
220 
    }
221 
    for (path, e) in entries {
222 
        w.bytes(path.as_bytes());
223 
        w.u64(e.size);
224 
        w.fixed(&e.mtime_ns.to_le_bytes());
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        w.fixed(&e.hash);
226 
        w.opt_object(&e.blob);
227 
        match e.graph {
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            None => w.u8(0),
229 
            Some(k) => {
230 
                w.u8(1);
231 
                w.fixed(&k);
232 
            }
233 
        }
234 
        w.u8(e.exec as u8);
235 
    }
236 
    let sum = manifest_sum(&w.0);
237 
    w.0[MANIFEST_SUM].copy_from_slice(&sum);
238 
    w.0
239 
}
240
241 
fn decode_manifest(buf: &[u8]) -> Option<(bool, bool, Manifest)> {
242 
    let mut r = crate::flat::Reader::new(buf);
243 
    if &r.fixed::<8>().ok()? != MANIFEST_MAGIC {
244 
        return None;
245 
    }
246 
    let conflicted = r.u8().ok()? == 1;
247 
    let uncommitted = r.u8().ok()? == 1;
248 
    let written_ns = u128::from_le_bytes(r.fixed().ok()?);
249 
    if r.fixed::<32>().ok()? != manifest_sum(buf) {
250 
        return None;
251 
    }
252 
    let mut dirs = Vec::new();
253 
    for _ in 0..r.count().ok()? {
254 
        let d = std::str::from_utf8(r.bytes().ok()?).ok()?.to_string();
255 
        dirs.push((d, u128::from_le_bytes(r.fixed().ok()?)));
256 
    }
257 
    let mut nested = Vec::new();
258 
    for _ in 0..r.count().ok()? {
259 
        nested.push(std::str::from_utf8(r.bytes().ok()?).ok()?.to_string());
260 
    }
261 
    let mut entries = Vec::new();
262 
    while !r.at_end() {
263 
        let path = std::str::from_utf8(r.bytes().ok()?).ok()?.to_string();
264 
        let e = ManifestEntry {
265 
            size: r.u64().ok()?,
266 
            mtime_ns: u128::from_le_bytes(r.fixed().ok()?),
267 
            hash: r.fixed().ok()?,
268 
            blob: r.opt_object().ok()?,
269 
            graph: match r.u8().ok()? {
270 
                0 => None,
271 
                _ => Some(r.fixed().ok()?),
272 
            },
273 
            exec: r.u8().ok()? == 1,
274 
        };
275 
        entries.push((path, e));
276 
    }
277 
    // Written in path order, so this builds the map without searching.
278 
    let entries = entries.into_iter().collect();
279 
    Some((
280 
        conflicted,
281 
        uncommitted,
282 
        Manifest {
283 
            written_ns,
284 
            entries,
285 
            dirs,
286 
            nested,
287 
        },
288 
    ))
289 
}
290
291 
/// The status cache: a magic number, the working-copy change, the
292 
/// manifest checksum, then each status line (a status byte and a path).
293 
const STATUS_MAGIC: &[u8; 8] = b"oxystat1";
294
295 
fn status_byte(s: ChangeStatus) -> u8 {
296 
    match s {
297 
        ChangeStatus::Added => 0,
298 
        ChangeStatus::Modified => 1,
299 
        ChangeStatus::Removed => 2,
300 
        ChangeStatus::Renamed => 3,
301 
        ChangeStatus::ModeChanged => 4,
302 
        ChangeStatus::ConflictEdited => 5,
303 
        ChangeStatus::Resolved => 6,
304 
    }
305 
}
306
307 
fn encode_status_cache(wc: &ChangeHash, stamp: &[u8; 32], statuses: &[PathStatus]) -> Vec<u8> {
308 
    let mut out = Vec::with_capacity(80 + statuses.len() * 40);
309 
    out.extend_from_slice(STATUS_MAGIC);
310 
    out.extend_from_slice(&wc.0);
311 
    out.extend_from_slice(stamp);
312 
    out.extend_from_slice(&(statuses.len() as u32).to_le_bytes());
313 
    for s in statuses {
314 
        out.push(status_byte(s.status));
315 
        out.extend_from_slice(&(s.path.len() as u32).to_le_bytes());
316 
        out.extend_from_slice(s.path.as_bytes());
317 
    }
318 
    out
319 
}
320
321 
fn decode_status_cache(b: &[u8]) -> Option<(ChangeHash, [u8; 32], Vec<PathStatus>)> {
322 
    let rest = b.strip_prefix(STATUS_MAGIC)?;
323 
    let wc = ObjectRef(rest.get(..32)?.try_into().ok()?);
324 
    let stamp: [u8; 32] = rest.get(32..64)?.try_into().ok()?;
325 
    let n = u32::from_le_bytes(rest.get(64..68)?.try_into().ok()?) as usize;
326 
    let mut at = 68;
327 
    let mut out = Vec::with_capacity(n.min(1 << 16));
328 
    for _ in 0..n {
329 
        let status = match *rest.get(at)? {
330 
            0 => ChangeStatus::Added,
331 
            1 => ChangeStatus::Modified,
332 
            2 => ChangeStatus::Removed,
333 
            3 => ChangeStatus::Renamed,
334 
            4 => ChangeStatus::ModeChanged,
335 
            5 => ChangeStatus::ConflictEdited,
336 
            6 => ChangeStatus::Resolved,
337 
            _ => return None,
338 
        };
339 
        let len = u32::from_le_bytes(rest.get(at + 1..at + 5)?.try_into().ok()?) as usize;
340 
        let path = std::str::from_utf8(rest.get(at + 5..at + 5 + len)?)
341 
            .ok()?
342 
            .to_string();
343 
        out.push(PathStatus { path, status });
344 
        at += 5 + len;
345 
    }
346 
    (at == rest.len()).then_some((wc, stamp, out))
347 
}
348
349 
impl Repo {
350 
    pub(crate) fn manifest_path(&self) -> PathBuf {
351 
        self.oxy
352 
            .join("workspaces")
353 
            .join(self.workspace.to_hex())
354 
            .join("manifest")
355 
    }
356
357 
    /// Record the working copy as it is now (after a snapshot, commit, or
358 
    /// checkout), with header lines saying whether the base state is
359 
    /// conflicted and whether the working-copy change holds uncommitted work.
360 
    pub(crate) fn write_manifest(&self, conflicted: bool, uncommitted: bool) -> Result<()> {
361 
        let entries = self.walk_working_copy()?;
362 
        self.write_manifest_entries(conflicted, uncommitted, &entries, &HashMap::new())
363 
    }
364
365 
    /// Write the manifest from entries already walked; `blobs` names the
366 
    /// stored blob of each opaque path so the next walk can skip reading it.
367 
    pub(crate) fn write_manifest_entries(
368 
        &self,
369 
        conflicted: bool,
370 
        uncommitted: bool,
371 
        entries: &BTreeMap<String, FsEntry>,
372 
        blobs: &HashMap<String, ObjectRef>,
373 
    ) -> Result<()> {
374 
        self.manifest_cache.take();
375 
        self.listing_cache.take();
376 
        let written = std::time::SystemTime::now()
377 
            .duration_since(UNIX_EPOCH)
378 
            .map(|d| d.as_nanos())
379 
            .unwrap_or(0);
380 
        let mut newest_ns: u128 = 0;
381 
        let mut rows = entries.iter().map(|(path, e)| {
382 
            let (size, mtime_ns) = match e.stat {
383 
                Some(known) => known,
384 
                None => match fs::symlink_metadata(self.root.join(path)) {
385 
                    Ok(m) => (m.len(), mtime_ns(&m)),
386 
                    Err(_) => (e.content.len() as u64, 0),
387 
                },
388 
            };
389 
            newest_ns = newest_ns.max(mtime_ns);
390 
            let entry = ManifestEntry {
391 
                size,
392 
                mtime_ns,
393 
                hash: e
394 
                    .content_hash
395 
                    .unwrap_or_else(|| *blake3::hash(&e.content).as_bytes()),
396 
                blob: blobs.get(path).copied().or(e.blob),
397 
                graph: e.graph_key,
398 
                exec: e.exec,
399 
            };
400 
            (path.as_str(), entry)
401 
        });
402 
        // The directories of the walk these entries came from, if any.
403 
        let (dirs, nested) = self.walked_dirs.take().unwrap_or_default();
404 
        let new = encode_manifest(conflicted, uncommitted, written, &dirs, &nested, &mut rows);
405 
        drop(rows);
406 
        let p = self.manifest_path();
407 
        // Leave an unchanged manifest alone when its stamp already trusts
408 
        // every entry (none is within the racy window): rewriting it would
409 
        // change nothing but the file, which editors watching the tree
410 
        // (and subrepos inside it) take as a change.
411 
        if let Ok(old) = fs::read(&p) {
412 
            let (w, sum) = (MANIFEST_WRITTEN, MANIFEST_SUM);
413 
            if old.len() == new.len()
414 
                && old[..w.start] == new[..w.start]
415 
                && old[sum.end..] == new[sum.end..]
416 
            {
417 
                let old_written = u128::from_le_bytes(old[w.clone()].try_into().unwrap());
418 
                if newest_ns + 2_000_000_000 < old_written {
419 
                    return Ok(());
420 
                }
421 
            }
422 
        }
423 
        fs::create_dir_all(p.parent().unwrap())?;
424 
        write_cache(&p, &new)
425 
    }
426
427 
    /// Change the header flags, and set the graph key of each path in
428 
    /// `keys` (after a commit, the new base's keys of the files it holds as
429 
    /// they are on disk).
430 
    pub(crate) fn rewrite_manifest(
431 
        &self,
432 
        conflicted: bool,
433 
        uncommitted: bool,
434 
        keys: &HashMap<String, [u8; 32]>,
435 
    ) -> Result<()> {
436 
        self.manifest_cache.take();
437 
        self.listing_cache.take();
438 
        let p = self.manifest_path();
439 
        let Some((_, _, m)) = fs::read(&p).ok().and_then(|b| decode_manifest(&b)) else {
440 
            return self.write_manifest(conflicted, uncommitted);
441 
        };
442 
        let mut rows = m.entries.iter().map(|(path, e)| {
443 
            let mut e = e.clone();
444 
            if let Some(k) = keys.get(path) {
445 
                e.graph = Some(*k);
446 
            }
447 
            (path.as_str(), e)
448 
        });
449 
        write_cache(
450 
            &p,
451 
            &encode_manifest(
452 
                conflicted,
453 
                uncommitted,
454 
                m.written_ns,
455 
                &m.dirs,
456 
                &m.nested,
457 
                &mut rows,
458 
            ),
459 
        )
460 
    }
461
462 
    /// Forget the manifest after an operation that changed the working-copy
463 
    /// change without a snapshot (undo, rewrites); the prompt shows blank
464 
    /// markers until the next snapshot.
465 
    pub(crate) fn drop_manifest(&self) {
466 
        self.manifest_cache.take();
467 
        self.listing_cache.take();
468 
        let _ = fs::remove_file(self.manifest_path());
469 
    }
470
471 
    /// The manifest, with whether it records a conflict and uncommitted
472 
    /// work; parsed once while the file stays the same one.
473 
    pub(crate) fn read_manifest(&self) -> Result<Option<(bool, bool, std::sync::Arc<Manifest>)>> {
474 
        let path = self.manifest_path();
475 
        let id = match fs::metadata(&path) {
476 
            Ok(m) => {
477 
                #[cfg(unix)]
478 
                let ino = std::os::unix::fs::MetadataExt::ino(&m);
479 
                #[cfg(not(unix))]
480 
                let ino = 0;
481 
                (m.len(), mtime_ns(&m), ino)
482 
            }
483 
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(None),
484 
            Err(e) => return Err(e.into()),
485 
        };
486 
        if let Some((cached_id, m)) = &*self.manifest_cache.borrow() {
487 
            if *cached_id == id {
488 
                return Ok(Some(m.clone()));
489 
            }
490 
        }
491 
        let Some((c, u, m)) = self.parse_manifest(&path)? else {
492 
            return Ok(None);
493 
        };
494 
        let m = (c, u, std::sync::Arc::new(m));
495 
        *self.manifest_cache.borrow_mut() = Some((id, m.clone()));
496 
        Ok(Some(m))
497 
    }
498
499 
    fn parse_manifest(&self, path: &std::path::Path) -> Result<Option<(bool, bool, Manifest)>> {
500 
        let buf = match fs::read(path) {
501 
            Ok(b) => b,
502 
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(None),
503 
            Err(e) => return Err(e.into()),
504 
        };
505 
        Ok(decode_manifest(&buf))
506 
    }
507
508 
    /// Whether the working copy is certainly clean, known from the manifest
509 
    /// alone, without loading any history (spec §12.4): the last snapshot
510 
    /// or commit found no uncommitted work and no conflict, there are no
511 
    /// subrepos (whose state the manifest does not hold), and no file was
512 
    /// added, removed or changed since. An entry inside the racy window,
513 
    /// where an equal size and time do not prove equal content, is checked
514 
    /// by hashing the file. `false` means only that a snapshot must decide.
515 
    pub fn clean_by_manifest(&self) -> Result<bool> {
516 
        let _t = crate::timing::phase("status: check the manifest");
517 
        // Why a snapshot must decide, with timings on.
518 
        let not = |why: &str| {
519 
            if crate::timing::enabled() {
520 
                eprintln!("timing status: not clean by the manifest: {why}");
521 
            }
522 
            Ok(false)
523 
        };
524 
        let Some((conflicted, uncommitted, m)) = self.read_manifest()? else {
525 
            return not("no manifest");
526 
        };
527 
        if conflicted || uncommitted || self.root.join(".oxymodules").exists() {
528 
            return not("conflicted, uncommitted or subrepos");
529 
        }
530 
        if self.disk_differs(&m, true)? {
531 
            return not("a file differs");
532 
        }
533 
        Ok(true)
534 
    }
535
536 
    /// A manifest entry written within the racy window whose file no
537 
    /// longer matches it. Such entries are hashed, in parallel (a checkout
538 
    /// just wrote them all).
539 
    fn racy_change(&self, m: &Manifest) -> Option<String> {
540 
        use rayon::prelude::*;
541 
        let racy: Vec<(&String, &ManifestEntry)> = m
542 
            .entries
543 
            .iter()
544 
            .filter(|(_, e)| e.mtime_ns + 2_000_000_000 >= m.written_ns)
545 
            .collect();
546 
        let root = &self.root;
547 
        racy.par_iter()
548 
            .find_any(|(rel, e)| {
549 
                let path = root.join(rel.as_str());
550 
                let same = match fs::symlink_metadata(&path) {
551 
                    Ok(md) if md.file_type().is_symlink() => fs::read_link(&path).is_ok_and(|t| {
552 
                        *blake3::hash(t.to_string_lossy().as_bytes()).as_bytes() == e.hash
553 
                    }),
554 
                    Ok(md) if md.is_file() => {
555 
                        md.len() == e.size
556 
                            && fs::read(&path).is_ok_and(|b| *blake3::hash(&b).as_bytes() == e.hash)
557 
                    }
558 
                    _ => false,
559 
                };
560 
                !same
561 
            })
562 
            .map(|(rel, _)| rel.to_string())
563 
    }
564
565 
    /// The status lines of the last snapshot, when the working copy is as
566 
    /// that snapshot left it: the cache it wrote names the working-copy
567 
    /// change and the manifest it recorded, and every file still matches
568 
    /// that manifest. `None` when a snapshot must decide (no cache, a file
569 
    /// changed, conflicts or subrepos). An empty list is a clean working
570 
    /// copy.
571 
    pub fn status_by_manifest(&self) -> Result<Option<Vec<PathStatus>>> {
572 
        // A listing left by an earlier check describes the files as they
573 
        // were then; this check makes its own.
574 
        self.listing_cache.take();
575 
        let Some((conflicted, uncommitted, m)) = self.read_manifest()? else {
576 
            return Ok(None);
577 
        };
578 
        if !uncommitted {
579 
            return Ok(self.clean_by_manifest()?.then(Vec::new));
580 
        }
581 
        let _t = crate::timing::phase("status: by the status cache");
582 
        if conflicted || self.root.join(".oxymodules").exists() {
583 
            return Ok(None);
584 
        }
585 
        let Some((wc, stamp, statuses)) = fs::read(self.status_cache_path())
586 
            .ok()
587 
            .and_then(|b| decode_status_cache(&b))
588 
        else {
589 
            return Ok(None);
590 
        };
591 
        let now = self.view()?.workspaces.get(&self.workspace).copied();
592 
        if now != Some(wc) || self.manifest_stamp() != Some(stamp) {
593 
            return Ok(None);
594 
        }
595 
        if self.disk_differs(&m, true)? {
596 
            return Ok(None);
597 
        }
598 
        // Test builds check the cache against a snapshot of the files.
599 
        #[cfg(test)]
600 
        {
601 
            let snap = self.snapshot_status("status cache check")?;
602 
            let key = |v: &[PathStatus]| {
603 
                let mut k: Vec<(String, u8)> = v
604 
                    .iter()
605 
                    .map(|p| (p.path.clone(), status_byte(p.status)))
606 
                    .collect();
607 
                k.sort();
608 
                k
609 
            };
610 
            assert_eq!(
611 
                key(&statuses),
612 
                key(&snap.statuses),
613 
                "status cache disagrees with a snapshot"
614 
            );
615 
        }
616 
        Ok(Some(statuses))
617 
    }
618
619 
    fn status_cache_path(&self) -> PathBuf {
620 
        self.manifest_path().with_file_name("status")
621 
    }
622
623 
    /// The manifest file's checksum, which names its content.
624 
    fn manifest_stamp(&self) -> Option<[u8; 32]> {
625 
        use std::io::Read;
626 
        let mut head = [0u8; MANIFEST_SUM.end];
627 
        fs::File::open(self.manifest_path())
628 
            .and_then(|mut f| f.read_exact(&mut head))
629 
            .ok()?;
630 
        head[MANIFEST_SUM].try_into().ok()
631 
    }
632
633 
    /// Record `statuses` as the status of working-copy change `wc` against
634 
    /// the manifest as it is now; with no uncommitted work there is nothing
635 
    /// to record, and the cache goes.
636 
    pub(crate) fn write_status_cache(&self, wc: Option<&ChangeHash>, statuses: &[PathStatus]) {
637 
        let path = self.status_cache_path();
638 
        let (Some(wc), Some(stamp)) = (wc, self.manifest_stamp()) else {
639 
            let _ = fs::remove_file(&path);
640 
            return;
641 
        };
642 
        let _ = write_cache(&path, &encode_status_cache(wc, &stamp, statuses));
643 
    }
644
645 
    /// Whether the working copy differs from the last manifest. Without a
646 
    /// manifest the answer is `None`.
647 
    pub fn quick_dirty(&self) -> Result<Option<bool>> {
648 
        self.quick_dirty_keeping(false)
649 
    }
650
651 
    /// `quick_dirty`; with `keep`, the listing it made is left for the
652 
    /// next walk of the working copy.
653 
    fn quick_dirty_keeping(&self, keep: bool) -> Result<Option<bool>> {
654 
        let Some((_, uncommitted, manifest)) = self.read_manifest()? else {
655 
            return Ok(None);
656 
        };
657 
        if uncommitted {
658 
            return Ok(Some(true));
659 
        }
660 
        Ok(Some(self.disk_differs(&manifest, keep)?))
661 
    }
662
663 
    /// Whether the working copy differs from `manifest`: a file added,
664 
    /// gone or changed. With `keep`, the listing made is left for the next
665 
    /// walk of the working copy when it does.
666 
    fn disk_differs(&self, manifest: &Manifest, keep: bool) -> Result<bool> {
667 
        // A file written within the racy window can change without its size
668 
        // or time moving (a coarse clock): those entries are hashed. One
669 
        // that changed still lets the directory check below hand its stats
670 
        // to the snapshot that follows.
671 
        let racy = self.racy_change(manifest).is_some();
672 
        if let Some(differs) = self.disk_differs_by_dirs_keeping(manifest, keep, racy) {
673 
            return Ok(differs || racy);
674 
        }
675 
        if racy {
676 
            return Ok(true);
677 
        }
678 
        self.disk_differs_listing(manifest, keep)
679 
    }
680
681 
    /// [`Repo::disk_differs`] without listing the tree, when the manifest
682 
    /// knows its directories: a directory's time moves when an entry is
683 
    /// added, removed or renamed in it, so with every directory's time as
684 
    /// recorded (and none within the racy window) the files are the
685 
    /// manifest's, and each is checked by its stat. `None` when a
686 
    /// directory changed or the manifest has none: the tree must be listed.
687 
    #[cfg(test)]
688 
    pub(crate) fn disk_differs_by_dirs(&self, manifest: &Manifest) -> Option<bool> {
689 
        self.disk_differs_by_dirs_keeping(manifest, false, false)
690 
    }
691
692 
    /// [`Repo::disk_differs_by_dirs`]; with `keep`, when a file differs
693 
    /// (or `racy` says one does), the stats taken become the listing of the
694 
    /// snapshot that follows: no directory's entries changed, so the
695 
    /// manifest's files are the tree's.
696 
    fn disk_differs_by_dirs_keeping(
697 
        &self,
698 
        manifest: &Manifest,
699 
        keep: bool,
700 
        racy: bool,
701 
    ) -> Option<bool> {
702 
        use rayon::prelude::*;
703 
        if manifest.dirs.is_empty() || !self.config.sparse_paths.is_empty() {
704 
            return None;
705 
        }
706 
        let _t = crate::timing::phase("status: directories and files by stat");
707 
        let root = &self.root;
708 
        let dirs_same = manifest.dirs.par_iter().all(|(rel, t)| {
709 
            *t + 2_000_000_000 < manifest.written_ns
710 
                && fs::metadata(root.join(rel)).is_ok_and(|m| m.is_dir() && mtime_ns(&m) == *t)
711 
        });
712 
        if !dirs_same {
713 
            return None;
714 
        }
715 
        // Each tracked path as it is now: a file's stat, a symlink's target.
716 
        enum Now {
717 
            File(PathBuf, fs::Metadata),
718 
            Link(Vec<u8>),
719 
        }
720 
        let differs_from = |me: &ManifestEntry, path: &Path, now: &Now| match now {
721 
            Now::Link(t) => *blake3::hash(t).as_bytes() != me.hash,
722 
            Now::File(_, m) => {
723 
                m.len() != me.size
724 
                    || super::is_executable(m) != me.exec
725 
                    || (mtime_ns(m) != me.mtime_ns
726 
                        && !fs::read(path).is_ok_and(|b| *blake3::hash(&b).as_bytes() == me.hash))
727 
            }
728 
        };
729 
        let stat = |rel: &str| -> Option<Now> {
730 
            let path = root.join(rel);
731 
            let m = fs::symlink_metadata(&path).ok()?;
732 
            if m.file_type().is_symlink() {
733 
                let t = fs::read_link(&path).ok()?;
734 
                Some(Now::Link(t.to_string_lossy().as_bytes().to_vec()))
735 
            } else if m.is_file() {
736 
                Some(Now::File(path, m))
737 
            } else {
738 
                None
739 
            }
740 
        };
741 
        let differs = if !keep {
742 
            manifest
743 
                .entries
744 
                .par_iter()
745 
                .any(|(rel, me)| match stat(rel) {
746 
                    Some(now) => differs_from(me, &root.join(rel.as_str()), &now),
747 
                    None => true,
748 
                })
749 
        } else {
750 
            let now: Vec<(&String, Option<Now>)> = manifest
751 
                .entries
752 
                .par_iter()
753 
                .map(|(rel, _)| (rel, stat(rel)))
754 
                .collect();
755 
            // A path gone or no longer a file: its directory moved, unless
756 
            // within a clock tick; list the tree to be sure.
757 
            if now.iter().any(|(_, n)| n.is_none()) {
758 
                return None;
759 
            }
760 
            let differs = now.par_iter().any(|(rel, n)| {
761 
                let me = &manifest.entries[*rel];
762 
                differs_from(me, &root.join(rel.as_str()), n.as_ref().unwrap())
763 
            });
764 
            if differs || racy {
765 
                let mut listing = super::walk::Listing {
766 
                    dirs: manifest.dirs.clone(),
767 
                    nested: manifest.nested.iter().map(|n| root.join(n)).collect(),
768 
                    ..Default::default()
769 
                };
770 
                for (rel, n) in now {
771 
                    match n.unwrap() {
772 
                        Now::File(path, m) => listing.files.push((rel.clone(), path, m)),
773 
                        Now::Link(t) => listing.symlinks.push((rel.clone(), t)),
774 
                    }
775 
                }
776 
                *self.listing_cache.borrow_mut() = Some(listing);
777 
            }
778 
            differs
779 
        };
780 
        if !differs {
781 
            // Nested repositories the manifest has no entry for are not
782 
            // subrepos: nothing in them is tracked (oxygen#43).
783 
            *self.untracked_nested.borrow_mut() = manifest
784 
                .nested
785 
                .iter()
786 
                .filter(|rel| !manifest.entries.contains_key(*rel))
787 
                .cloned()
788 
                .collect();
789 
        }
790 
        Some(differs)
791 
    }
792
793 
    /// [`Repo::disk_differs`] by listing the tree.
794 
    fn disk_differs_listing(&self, manifest: &Manifest, keep: bool) -> Result<bool> {
795 
        use rayon::prelude::*;
796 
        let sparse = &self.config.sparse_paths;
797 
        let in_scope = |p: &str| {
798 
            sparse.is_empty()
799 
                || sparse
800 
                    .iter()
801 
                    .any(|s| p == s || p.starts_with(&format!("{s}/")))
802 
        };
803 
        // A working copy that cannot be listed counts as changed.
804 
        // Known files are not matched against the ignore rules: with no
805 
        // uncommitted work (the clean check), the manifest's files are the
806 
        // base's, and a prompt's answer is the same either way.
807 
        let known = |p: &str| manifest.entries.contains_key(p);
808 
        let Ok(listing) = super::walk::list_knowing(&self.root, &in_scope, &known) else {
809 
            return Ok(true);
810 
        };
811 
        let differs = || -> Result<bool> {
812 
            let links_differ = listing.symlinks.iter().any(|(rel, target)| {
813 
                manifest
814 
                    .entries
815 
                    .get(rel)
816 
                    .is_none_or(|me| *blake3::hash(target).as_bytes() != me.hash)
817 
            });
818 
            if links_differ {
819 
                return Ok(true);
820 
            }
821 
            // Each file is checked on its own, in parallel, stopping at the
822 
            // first difference; an unreadable one counts as different.
823 
            let files_differ = listing.files.par_iter().any(|(rel, path, m)| {
824 
                manifest.entries.get(rel).is_none_or(|me| {
825 
                    m.len() != me.size
826 
                        || super::is_executable(m) != me.exec
827 
                        || (mtime_ns(m) != me.mtime_ns
828 
                            && !fs::read(path)
829 
                                .is_ok_and(|b| *blake3::hash(&b).as_bytes() == me.hash))
830 
                })
831 
            });
832 
            if files_differ {
833 
                return Ok(true);
834 
            }
835 
            let seen = listing.files.len() + listing.symlinks.len();
836 
            if seen == manifest.entries.len() {
837 
                return Ok(false);
838 
            }
839 
            // Manifest entries the walk skipped: tracked files that ignore
840 
            // rules hide (Linux tracks some its own .gitignore names). Found
841 
            // by merging the two sorted lists; they count as present when
842 
            // still on disk and unchanged, checked on every core.
843 
            let mut listed: Vec<&str> = listing
844 
                .files
845 
                .iter()
846 
                .map(|(r, _, _)| r.as_str())
847 
                .chain(listing.symlinks.iter().map(|(r, _)| r.as_str()))
848 
                .collect();
849 
            listed.sort_unstable();
850 
            let mut at = listed.iter().peekable();
851 
            let skipped: Vec<(&String, &ManifestEntry)> = manifest
852 
                .entries
853 
                .iter()
854 
                .filter(|(rel, _)| {
855 
                    while at.next_if(|l| **l < rel.as_str()).is_some() {}
856 
                    at.peek().is_none_or(|l| **l != rel.as_str())
857 
                })
858 
                .collect();
859 
            let root = &self.root;
860 
            Ok(skipped.par_iter().any(|(rel, me)| {
861 
                let path = root.join(rel.as_str());
862 
                let Ok(m) = fs::symlink_metadata(&path) else {
863 
                    return true;
864 
                };
865 
                !m.file_type().is_symlink()
866 
                    && (m.len() != me.size
867 
                        || super::is_executable(&m) != me.exec
868 
                        || (mtime_ns(&m) != me.mtime_ns
869 
                            && !fs::read(&path)
870 
                                .is_ok_and(|b| *blake3::hash(&b).as_bytes() == me.hash)))
871 
            }))
872 
        };
873 
        let dirty = differs()?;
874 
        if !dirty {
875 
            // Nested repositories the manifest has no entry for are not
876 
            // subrepos: nothing in them is tracked (oxygen#43).
877 
            *self.untracked_nested.borrow_mut() = listing
878 
                .nested
879 
                .iter()
880 
                .map(|d| self.rel_path(d))
881 
                .filter(|rel| !manifest.entries.contains_key(rel))
882 
                .collect();
883 
        }
884 
        if dirty && keep {
885 
            *self.listing_cache.borrow_mut() = Some(listing);
886 
        }
887 
        Ok(dirty)
888 
    }
889
890 
    /// Prompt information without recording anything.
891 
    pub fn quick_status(&self) -> Result<PromptInfo> {
892 
        let view = self.view()?;
893 
        let bookmark = self.config.bookmark.clone();
894 
        let heads = self.heads_of(&view, &bookmark)?;
895 
        let wc_hash = view.workspaces.get(&self.workspace).copied();
896 
        let change_id = match wc_hash {
897 
            Some(h) => self.store.get_change_meta(&h)?.change_id.short(8),
898 
            None => String::new(),
899 
        };
900 
        // Conflictedness was recorded by the last snapshot; without a
901 
        // manifest (never snapshotted) both flags are unknown and shown clear.
902 
        let manifest = self.read_manifest()?;
903 
        let conflicted = manifest.as_ref().map(|(c, _, _)| *c).unwrap_or(false);
904 
        let dirty = self.quick_dirty()?.unwrap_or(false);
905 
        let (ahead, behind) = match view.remotes.get("origin").and_then(|b| b.get(&bookmark)) {
906 
            Some(st) => {
907 
                let remote_heads = self.store.get_state(st)?.heads;
908 
                let ahead = self.negotiate(&remote_heads, &heads).map(|v| v.len()).ok();
909 
                let behind = self.negotiate(&heads, &remote_heads).map(|v| v.len()).ok();
910 
                (ahead, behind)
911 
            }
912 
            None => (None, None),
913 
        };
914 
        Ok(PromptInfo {
915 
            bookmark,
916 
            change_id,
917 
            heads: heads.len(),
918 
            dirty,
919 
            conflicted,
920 
            ahead,
921 
            behind,
922 
        })
923 
    }
924 
}
925
926 
#[cfg(test)]
927 
mod tests {
928 
    use super::*;
929
930 
    #[test]
931 
    fn placeholders_and_glyphs() {
932 
        let clean = PromptInfo {
933 
            bookmark: "main".into(),
934 
            change_id: "658990aa".into(),
935 
            heads: 1,
936 
            dirty: false,
937 
            conflicted: false,
938 
            ahead: Some(0),
939 
            behind: None,
940 
        };
941 
        assert_eq!(clean.format(DEFAULT_PROMPT_FORMAT), "main 658990aa");
942 
        assert_eq!(clean.format(GLYPH_PROMPT_FORMAT), "⚛ main 658990aa ✔");
943 
        let busy = PromptInfo {
944 
            dirty: true,
945 
            ahead: Some(2),
946 
            behind: Some(3),
947 
            ..clean.clone()
948 
        };
949 
        assert_eq!(busy.format(DEFAULT_PROMPT_FORMAT), "main 658990aa*+2-3");
950 
        assert_eq!(busy.format(GLYPH_PROMPT_FORMAT), "⚛ main 658990aa ✎↑2↓3");
951 
        let bad = PromptInfo {
952 
            conflicted: true,
953 
            ..busy.clone()
954 
        };
955 
        assert_eq!(bad.format("%s%x%d %h %a/%B %%"), "‼!* 1 2/3 %");
956 
        assert_eq!(bad.state_color(), 31);
957 
        assert_eq!(
958 
            busy.format_colored("%b", ("\\[", "\\]")),
959 
            "\\[\x1b[33m\\]main\\[\x1b[0m\\]"
960 
        );
961 
        assert_eq!(clean.format_colored("%b", ("", "")), "\x1b[36mmain\x1b[0m");
962 
        assert_eq!(clean.format("%q"), "%q");
963 
    }
964 
}