OXYGENHUB
# 5259a3af8ee6 oxygen / crates / oxy-core / src / repo / sync.rs
34.3 KiB · Rust · last changed Lazy blobs: clone --max-blob / filter.max-blob, absent-blob registry fetched on first read, objects endpoint (spec 0.6e) 1 month ago source blame history raw
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//! Serving and talking to remotes (spec §10.2, §16).
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use super::*;
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/// What a fetch brought in.
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#[derive(Debug, Clone, PartialEq, Eq, Default)]
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pub struct FetchReport {
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    /// Bookmark name, its heads, and how many changes were new.
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    pub refs: Vec<(String, Vec<ChangeHash>, usize)>,
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    /// The remote has never presented a policy, so nothing was verified
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    /// against one (spec §14.5: warn loudly).
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    pub unverified: bool,
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}
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#[derive(Debug, Clone, PartialEq, Eq)]
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pub struct PullReport {
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    pub heads: Vec<ChangeHash>,
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    pub changed: bool,
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    pub checked_out: bool,
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}
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impl Repo {
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    // ------------------------------------------------------------ serving (spec §16)
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    fn ref_attest_path(&self, bookmark: &str) -> PathBuf {
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        self.oxy.join("attest").join(bookmark)
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    }
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    /// The latest reference attestation stored for a bookmark.
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    pub fn latest_ref_attest(&self, bookmark: &str) -> Result<Option<(ObjectRef, SignedAttest)>> {
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        match fs::read_to_string(self.ref_attest_path(bookmark)) {
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            Ok(h) => {
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                let r = ObjectRef::from_hex(h.trim()).ok_or_else(|| RepoError::Msg("corrupt attestation pointer".into()))?;
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                Ok(Some((r, SignedAttest { attest: self.store.get_attest(&r)?, sigs: self.store.signatures(&r)? })))
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            }
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            Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(None),
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            Err(e) => Err(e.into()),
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        }
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    }
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    fn set_ref_attest(&self, bookmark: &str, r: &ObjectRef) -> Result<()> {
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        fs::create_dir_all(self.oxy.join("attest"))?;
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        write_atomic(&self.ref_attest_path(bookmark), r.to_hex().as_bytes())
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    }
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    pub fn remote_refs(&self) -> Result<RefsResponse> {
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        let view = self.view()?;
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        let mut out = Vec::new();
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        for (name, state) in &view.bookmarks {
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            let latest = self.latest_ref_attest(name)?.map(|(_, a)| a);
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            let last_serial = latest.as_ref().and_then(|a| match a.attest.body {
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                AttestBody::Ref { serial, .. } => Some(serial),
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                _ => None,
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            });
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            let attestation = latest.filter(|a| matches!(&a.attest.body, AttestBody::Ref { new_state, .. } if new_state == state));
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            out.push(RemoteRef { name: name.clone(), state: *state, heads: self.store.get_state(state)?.heads, attestation, last_serial });
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        }
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        Ok(RefsResponse { refs: out, policy: self.current_policy()?.map(|(_, sp)| sp) })
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    }
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    /// Every change reachable from `heads` that is in the store.
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    fn closure_in_store(&self, heads: &[ChangeHash]) -> Result<BTreeSet<ChangeHash>> {
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        let mut seen = BTreeSet::new();
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        let mut stack: Vec<ChangeHash> = heads.to_vec();
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        while let Some(h) = stack.pop() {
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            if seen.contains(&h) || !self.store.has(&h) {
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                continue;
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            }
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            seen.insert(h);
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            stack.extend(self.store.get_change(&h)?.deps);
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        }
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        Ok(seen)
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    }
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    /// `closure(want) \ closure(have)`, dependencies first (spec §16.2).
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    pub fn negotiate(&self, have: &[ChangeHash], want: &[ChangeHash]) -> Result<Vec<ChangeHash>> {
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        let have = self.closure_in_store(have)?;
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        let mut out = Vec::new();
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        let mut done: BTreeSet<ChangeHash> = have.clone();
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        // Iterative post-order DFS.
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        let mut stack: Vec<(ChangeHash, bool)> = want.iter().rev().map(|h| (*h, false)).collect();
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        while let Some((h, expanded)) = stack.pop() {
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            if done.contains(&h) {
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                continue;
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            }
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            if !self.store.has(&h) {
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                return fail(format!("change {} is not in this repository", h.short(12)));
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            }
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            if expanded {
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                done.insert(h);
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                out.push(h);
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                continue;
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            }
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            stack.push((h, true));
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            for d in self.store.get_change(&h)?.deps {
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                if !done.contains(&d) {
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                    stack.push((d, false));
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                }
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            }
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        }
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        Ok(out)
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    }
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    /// Bundle changes (in the given dependency order) with their signatures,
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    /// seals, identities, blobs, chunks.
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    pub fn bundle_for(&self, changes: &[ChangeHash]) -> Result<Bundle> {
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        self.bundle_for_filtered(changes, None)
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    }
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    /// Objects by reference for the `objects` endpoint; a blob brings its chunks.
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    pub fn objects_for(&self, refs: &[ObjectRef]) -> Result<Vec<(ObjectType, Vec<u8>)>> {
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        let mut out = Vec::new();
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        for r in refs {
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            let (ty, body) = match self.store.get(r) {
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                Ok(x) => x,
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                Err(StoreError::NotFound(_)) => continue,
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                Err(e) => return Err(e.into()),
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            };
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            if ty == ObjectType::Blob {
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                for c in Blob::decode(&body)?.chunks {
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                    if let Ok((cty, cb)) = self.store.get(&c) {
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                        out.push((cty, cb));
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                    }
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                }
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            }
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            out.push((ty, body));
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        }
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        Ok(out)
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    }
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    /// Like `bundle_for`, leaving out blobs larger than `max_blob` bytes
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    /// (and their chunks) so the receiver fetches them lazily (spec §13.5).
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    pub fn bundle_for_filtered(&self, changes: &[ChangeHash], max_blob: Option<u64>) -> Result<Bundle> {
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        let mut bundle = Bundle::default();
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        let mut objects: BTreeSet<ObjectRef> = BTreeSet::new();
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        let mut seals: BTreeSet<ObjectRef> = BTreeSet::new();
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        let add_object = |r: &ObjectRef, objects: &mut BTreeSet<ObjectRef>| {
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            if !r.is_zero() && self.store.has(r) {
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                objects.insert(*r);
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            }
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        };
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        for h in changes {
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            let c = self.store.get_change(h)?;
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            let sigs = self.store.signatures(h)?;
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            add_object(&c.author, &mut objects);
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            for s in &sigs {
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                add_object(&s.key, &mut objects);
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            }
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            for e in &c.edits {
150 
                if let Edit::Replace { old, new, .. } = e {
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                    for b in [old, new].into_iter().flatten() {
152 
                        if self.store.has(b) {
153 
                            if let Ok(blob) = Blob::decode(&self.store.get_typed(b, ObjectType::Blob)?) {
154 
                                if max_blob.is_some_and(|m| blob.length > m) {
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                                    continue;
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                                }
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                                objects.insert(*b);
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                                objects.extend(blob.chunks.iter().copied());
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                            }
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                        }
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                    }
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                }
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            }
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            for s in self.store.seals_for(h)? {
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                seals.insert(s);
166 
            }
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            bundle.changes.push((c, sigs));
168 
        }
169 
        for r in seals {
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            let attest = self.store.get_attest(&r)?;
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            let sigs = self.store.signatures(&r)?;
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            for s in &sigs {
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                add_object(&s.key, &mut objects);
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            }
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            bundle.attests.push(SignedAttest { attest, sigs });
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        }
177 
        for r in objects {
178 
            let (ty, body) = self.store.get(&r)?;
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            bundle.objects.push((ty, body));
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        }
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        Ok(bundle)
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    }
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    /// Store a bundle's contents. With `strict`, every change must
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    /// authenticate (signature or seal by its author or a delegate).
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    pub fn import_bundle(&self, bundle: &Bundle, strict: bool) -> Result<Vec<ChangeHash>> {
187 
        for (ty, body) in &bundle.objects {
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            match ty {
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                ObjectType::Chunk | ObjectType::Blob | ObjectType::Identity | ObjectType::State => {
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                    self.store.put(*ty, body)?;
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                }
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                other => return fail(format!("bundle may not carry {} objects", other.name())),
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            }
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        }
195 
        for sa in &bundle.attests {
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            let r = self.store.put_attest(&sa.attest)?;
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            for sig in &sa.sigs {
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                self.store.put_signature(&r, sig)?;
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            }
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            if let AttestBody::Seal { hashes } = &sa.attest.body {
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                for h in hashes {
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                    self.store.index_seal(h, &r)?;
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                }
204 
            }
205 
        }
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        let incoming: BTreeSet<ChangeHash> = bundle.changes.iter().map(|(c, _)| c.hash()).collect();
207 
        let mut imported = Vec::new();
208 
        for (c, sigs) in &bundle.changes {
209 
            let h = c.hash();
210 
            for d in &c.deps {
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                if !self.store.has(d) && !incoming.contains(d) {
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                    return fail(format!("change {} depends on {}, which is neither stored nor in the bundle", h.short(12), d.short(12)));
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                }
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            }
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            self.store.put_change(c)?;
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            for sig in sigs {
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                self.store.put_signature(&h, sig)?;
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            }
219 
            imported.push(h);
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        }
221 
        if strict {
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            for h in &imported {
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                if !matches!(self.authenticate_change(h)?, SignatureStatus::Valid { .. }) {
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                    return fail(format!("change {} is not authenticated by its author", h.short(12)));
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                }
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            }
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        }
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        Ok(imported)
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    }
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    /// Verify a reference attestation against an update it claims to describe.
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    /// `allow_equal` lets a client re-read the attestation it already has; a
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    /// server receiving a push requires a strictly greater serial.
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    fn check_ref_attest(&self, sa: &SignedAttest, name: &str, old_state: &ObjectRef, new_state: &ObjectRef, last_serial: Option<u64>, allow_equal: bool) -> std::result::Result<u64, String> {
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        let AttestBody::Ref { name: n, old_state: o, new_state: nw, serial } = &sa.attest.body else {
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            return Err("attestation is not a ref attestation".into());
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        };
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        if n != name || o != old_state || nw != new_state {
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            return Err("attestation does not describe this update".into());
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        }
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        if sa.attest.repo != self.id().map_err(|e| e.to_string())? {
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            return Err("attestation is for a different repository".into());
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        }
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        if let Some(last) = last_serial {
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            if *serial < last || (*serial == last && !allow_equal) {
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                return Err(format!("attestation serial {serial} is not greater than the last seen {last}"));
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            }
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        }
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        let r = sa.attest.hash();
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        let sig = sa.sigs.first().ok_or("attestation carries no signature")?;
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        let id = self.store.get_identity(&sig.key).map_err(|_| format!("unknown key {}", sig.key.short(12)))?;
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        verify_signature(&id, sig, Domain::Attest, &r).map_err(|e| e.to_string())?;
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        Ok(*serial)
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    }
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    /// Accept a push (spec §16.4). Without a trust policy every repository
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    /// is unverified, so unsigned changes and unattested updates are accepted;
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    /// attestations that are present must still be valid. With a policy,
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    /// every change and update is checked against it. A newer policy in the
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    /// push is applied first when it is signed by the current roots.
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    pub fn receive_push(&self, bundle: Bundle, updates: Vec<RefUpdate>, policy: Option<SignedPolicy>) -> Result<Vec<RefResult>> {
262 
        let mut results = Vec::new();
263 
        if let Some(sp) = policy {
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            let current = self.current_policy()?.map(|(_, c)| c.policy);
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            match self.check_policy(&sp, current.as_ref()) {
266 
                Ok(()) => {
267 
                    self.set_policy(&sp, &format!("push received: policy serial {}", sp.policy.serial))?;
268 
                    results.push(RefResult { name: "policy".into(), ok: true, reason: format!("serial {}", sp.policy.serial) });
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                }
270 
                Err(e) => {
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                    results.push(RefResult { name: "policy".into(), ok: false, reason: e });
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                    for u in updates {
273 
                        results.push(RefResult { name: u.name, ok: false, reason: "policy update was rejected".into() });
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                    }
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                    return Ok(results);
276 
                }
277 
            }
278 
        }
279 
        let policy = self.current_policy()?.map(|(_, sp)| sp.policy);
280 
        if let Err(e) = self.import_bundle(&bundle, policy.is_some()) {
281 
            for u in updates {
282 
                results.push(RefResult { name: u.name, ok: false, reason: e.to_string() });
283 
            }
284 
            return Ok(results);
285 
        }
286 
        let (op_ref, op) = self.head_op()?;
287 
        let mut view = op.view.clone();
288 
        let mut names = Vec::new();
289 
        for u in updates {
290 
            let outcome = self.apply_update(&mut view, &u, policy.as_ref());
291 
            let (ok, reason) = match outcome {
292 
                Ok(()) => (true, String::new()),
293 
                Err(e) => (false, e),
294 
            };
295 
            if ok {
296 
                names.push(u.name.clone());
297 
            }
298 
            results.push(RefResult { name: u.name, ok, reason });
299 
        }
300 
        if !names.is_empty() {
301 
            self.record_op(&[op_ref], &format!("push received: {}", names.join(" ")), view)?;
302 
        }
303 
        Ok(results)
304 
    }
305
306 
    fn apply_update(&self, view: &mut View, u: &RefUpdate, policy: Option<&crate::policy::Policy>) -> std::result::Result<(), String> {
307 
        if u.name == "policy" {
308 
            return Err("the policy reference is updated by sending a policy, not a bookmark update".into());
309 
        }
310 
        let empty = self.store.put_state(&StateObject::new(vec![])).map_err(|e| e.to_string())?;
311 
        let current = view.bookmarks.get(&u.name).copied().unwrap_or(empty);
312 
        if current != u.old_state {
313 
            return Err("stale: the remote bookmark has moved; pull first".into());
314 
        }
315 
        let new_state = self.store.get_state(&u.new_state).map_err(|_| "new state object is missing".to_string())?;
316 
        for h in &new_state.heads {
317 
            if !self.store.has(h) {
318 
                return Err(format!("head {} is missing", h.short(12)));
319 
            }
320 
        }
321 
        if !u.force {
322 
            let old_heads = self.store.get_state(&current).map_err(|e| e.to_string())?.heads;
323 
            let closure = self.closure_in_store(&new_state.heads).map_err(|e| e.to_string())?;
324 
            if let Some(h) = old_heads.iter().find(|h| !closure.contains(h)) {
325 
                return Err(format!("not a fast-forward: current head {} would be dropped (use --force)", h.short(12)));
326 
            }
327 
        }
328 
        if let Some(p) = policy {
329 
            let Some(sa) = &u.attestation else {
330 
                return Err(format!("{:?} requires a signed reference attestation under this repository's policy", u.name));
331 
            };
332 
            let signer = sa.sigs.first().map(|s| s.key).ok_or("attestation carries no signature")?;
333 
            if !p.authorizes(&signer, &u.name) {
334 
                return Err(format!("key {} may not update {:?} under this repository's policy", signer.short(12), u.name));
335 
            }
336 
            let old_heads = self.store.get_state(&current).map_err(|e| e.to_string())?.heads;
337 
            self.state_allowed(&old_heads, &new_state.heads, p, &u.name)?;
338 
        }
339 
        if let Some(sa) = &u.attestation {
340 
            let last = self.latest_ref_attest(&u.name).map_err(|e| e.to_string())?.and_then(|(_, a)| match a.attest.body {
341 
                AttestBody::Ref { serial, .. } => Some(serial),
342 
                _ => None,
343 
            });
344 
            self.check_ref_attest(sa, &u.name, &u.old_state, &u.new_state, last, false)?;
345 
            let r = self.store.put_attest(&sa.attest).map_err(|e| e.to_string())?;
346 
            for sig in &sa.sigs {
347 
                self.store.put_signature(&r, sig).map_err(|e| e.to_string())?;
348 
            }
349 
            self.set_ref_attest(&u.name, &r).map_err(|e| e.to_string())?;
350 
        }
351 
        view.bookmarks.insert(u.name.clone(), u.new_state);
352 
        Ok(())
353 
    }
354
355 
    // ------------------------------------------------------------ client side
356
357 
    fn remote_url(&self, name: &str) -> Result<String> {
358 
        self.config.remotes.get(name).cloned().ok_or_else(|| RepoError::Msg(format!("no remote named {name:?}; add one with `oxy remote add`")))
359 
    }
360
361 
    /// Credentials and trust for a remote: `remote.<name>.token` (else
362 
    /// `$OXY_TOKEN`) and `remote.<name>.ca` (else `$OXY_CA`).
363 
    fn remote_options(&self, name: &str) -> RemoteOptions {
364 
        RemoteOptions {
365 
            token: self.config.remote_tokens.get(name).cloned().or_else(|| std::env::var("OXY_TOKEN").ok()),
366 
            ca: self.config.remote_cas.get(name).map(PathBuf::from).or_else(|| std::env::var("OXY_CA").ok().map(PathBuf::from)),
367 
        }
368 
    }
369
370 
    fn open_named_remote(&self, name: &str) -> Result<Box<dyn crate::protocol::Remote>> {
371 
        open_remote(&self.remote_url(name)?, &self.remote_options(name))
372 
    }
373
374 
    fn serial_path(&self, remote: &str, bookmark: &str) -> PathBuf {
375 
        self.oxy.join("remotes").join(remote).join(format!("{bookmark}.serial"))
376 
    }
377
378 
    fn last_seen_serial(&self, remote: &str, bookmark: &str) -> Option<u64> {
379 
        fs::read_to_string(self.serial_path(remote, bookmark)).ok().and_then(|s| s.trim().parse().ok())
380 
    }
381
382 
    fn record_serial(&self, remote: &str, bookmark: &str, serial: u64) -> Result<()> {
383 
        let p = self.serial_path(remote, bookmark);
384 
        fs::create_dir_all(p.parent().unwrap())?;
385 
        write_atomic(&p, serial.to_string().as_bytes())
386 
    }
387
388 
    fn policy_serial_path(&self, remote: &str) -> PathBuf {
389 
        self.oxy.join("remotes").join(remote).join("policy.serial")
390 
    }
391
392 
    /// The highest policy serial `remote` has ever presented.
393 
    fn remote_policy_serial(&self, remote: &str) -> Option<u64> {
394 
        fs::read_to_string(self.policy_serial_path(remote)).ok().and_then(|s| s.trim().parse().ok())
395 
    }
396
397 
    fn record_policy_serial(&self, remote: &str, serial: u64) -> Result<()> {
398 
        let p = self.policy_serial_path(remote);
399 
        fs::create_dir_all(p.parent().unwrap())?;
400 
        write_atomic(&p, serial.to_string().as_bytes())
401 
    }
402
403 
    fn lazy_dir(&self) -> PathBuf {
404 
        self.oxy.join("lazy")
405 
    }
406
407 
    /// Remember that `blob` was withheld by `remote` (spec §13.5).
408 
    fn register_lazy(&self, blob: &ObjectRef, remote: &str) -> Result<()> {
409 
        fs::create_dir_all(self.lazy_dir())?;
410 
        write_atomic(&self.lazy_dir().join(blob.to_hex()), remote.as_bytes())
411 
    }
412
413 
    /// Which remote promised an absent blob, if any.
414 
    pub fn lazy_remote(&self, blob: &ObjectRef) -> Option<String> {
415 
        fs::read_to_string(self.lazy_dir().join(blob.to_hex())).ok().map(|s| s.trim().to_string())
416 
    }
417
418 
    /// Fetch an absent blob (and its chunks) from the remote that promised it.
419 
    pub(crate) fn fetch_lazy_blob(&self, blob: &ObjectRef) -> Result<()> {
420 
        let Some(remote_name) = self.lazy_remote(blob) else {
421 
            return Err(RepoError::Store(StoreError::NotFound(*blob)));
422 
        };
423 
        let remote = self.open_named_remote(&remote_name)?;
424 
        let objects = remote.objects(&[*blob])?;
425 
        for (ty, body) in objects {
426 
            if matches!(ty, ObjectType::Blob | ObjectType::Chunk) {
427 
                self.store.put(ty, &body)?;
428 
            }
429 
        }
430 
        if !self.store.has(blob) {
431 
            return fail(format!("{remote_name} did not send blob {}", blob.short(12)));
432 
        }
433 
        let _ = fs::remove_file(self.lazy_dir().join(blob.to_hex()));
434 
        Ok(())
435 
    }
436
437 
    /// After importing from `remote`, record every blob the changes reference
438 
    /// that the store lacks as lazily available from that remote.
439 
    fn register_missing_blobs(&self, changes: &[ChangeHash], remote: &str) -> Result<usize> {
440 
        let mut n = 0;
441 
        for h in changes {
442 
            let c = self.store.get_change(h)?;
443 
            for e in &c.edits {
444 
                if let Edit::Replace { old, new, .. } = e {
445 
                    for b in [old, new].into_iter().flatten() {
446 
                        if !self.store.has(b) {
447 
                            self.register_lazy(b, remote)?;
448 
                            n += 1;
449 
                        }
450 
                    }
451 
                }
452 
            }
453 
        }
454 
        Ok(n)
455 
    }
456
457 
    /// Every head this repository knows: bookmarks, remote tracking, working copy.
458 
    fn known_heads(&self, view: &View) -> Result<Vec<ChangeHash>> {
459 
        let mut have: BTreeSet<ChangeHash> = BTreeSet::new();
460 
        for st in view.bookmarks.values().chain(view.remotes.values().flat_map(|b| b.values())) {
461 
            if let Ok(s) = self.store.get_state(st) {
462 
                have.extend(s.heads);
463 
            }
464 
        }
465 
        have.extend(view.workspaces.values().copied());
466 
        Ok(have.into_iter().collect())
467 
    }
468
469 
    /// Fetch every bookmark of a remote into `remotes/<name>/bookmarks/*` (spec §10.2).
470 
    pub fn fetch(&self, remote_name: &str) -> Result<FetchReport> {
471 
        let remote = self.open_named_remote(remote_name)?;
472 
        if remote.repo_id()? != self.id()? {
473 
            return fail(format!("remote {remote_name:?} is a different repository (repository IDs differ)"));
474 
        }
475 
        let resp = remote.refs()?;
476 
        // Trust policy (spec §14.5). Adopt the remote's policy when it is newer
477 
        // and signed by roots we trust, or on first contact. A remote that
478 
        // once presented a policy may never present none or an older one:
479 
        // that is a downgrade. A remote that never presented one is
480 
        // unverified, and this fetch is checked only as far as possible.
481 
        let local_policy = self.current_policy()?.map(|(_, sp)| sp.policy);
482 
        let seen = self.remote_policy_serial(remote_name);
483 
        let mut unverified = false;
484 
        match &resp.policy {
485 
            Some(sp) => {
486 
                if seen.is_some_and(|s| sp.policy.serial < s) {
487 
                    return fail(format!("{remote_name} presents policy serial {} but presented {} before: refusing the downgrade", sp.policy.serial, seen.unwrap()));
488 
                }
489 
                match &local_policy {
490 
                    Some(l) if sp.policy.serial < l.serial => {}
491 
                    Some(l) if sp.policy.serial == l.serial => {
492 
                        if sp.policy.hash() != l.hash() {
493 
                            return fail(format!("{remote_name} presents a different policy with the same serial {}", l.serial));
494 
                        }
495 
                    }
496 
                    local => {
497 
                        self.check_policy(sp, local.as_ref()).map_err(|e| RepoError::Msg(format!("policy from {remote_name}: {e}")))?;
498 
                        self.set_policy(sp, &format!("oxy fetch {remote_name} (policy serial {})", sp.policy.serial))?;
499 
                    }
500 
                }
501 
                self.record_policy_serial(remote_name, sp.policy.serial)?;
502 
            }
503 
            None => {
504 
                if seen.is_some() {
505 
                    return fail(format!("{remote_name} presented a policy before but has none now: refusing the downgrade"));
506 
                }
507 
                unverified = true;
508 
            }
509 
        }
510 
        let policy = if unverified { None } else { self.current_policy()?.map(|(_, sp)| sp.policy) };
511 
        let (op_ref, op) = self.head_op()?;
512 
        let mut view = op.view.clone();
513 
        let have = self.known_heads(&view)?;
514 
        let mut report = Vec::new();
515 
        let max_blob = self.config.max_blob;
516 
        for r in resp.refs {
517 
            let needed = remote.negotiate(&have, &r.heads)?;
518 
            let bundle = remote.fetch(&needed, max_blob)?;
519 
            // Changes are not individually re-verified here: the bookmark's
520 
            // attestation (checked below) binds its whole state, and the
521 
            // receiver of the push verified the added changes at that time.
522 
            let imported = self.import_bundle(&bundle, false)?;
523 
            if max_blob.is_some() {
524 
                self.register_missing_blobs(&imported, remote_name)?;
525 
            }
526 
            for h in &r.heads {
527 
                if !self.store.has(h) {
528 
                    return fail(format!("remote did not send head {}", h.short(12)));
529 
                }
530 
            }
531 
            let state = self.store.put_state(&StateObject::new(r.heads.clone()))?;
532 
            if state != r.state {
533 
                return fail(format!("remote state {} does not match its heads", r.state.short(12)));
534 
            }
535 
            if let Some(p) = &policy {
536 
                let Some(sa) = &r.attestation else {
537 
                    return fail(format!("{remote_name}/{} has no attestation, which its policy requires", r.name));
538 
                };
539 
                let signer = sa.sigs.first().map(|s| s.key).ok_or_else(|| RepoError::Msg("attestation carries no signature".into()))?;
540 
                if !p.authorizes(&signer, &r.name) {
541 
                    return fail(format!("{remote_name}/{}: attested by {}, which the policy does not authorize", r.name, signer.short(12)));
542 
                }
543 
            }
544 
            if let Some(sa) = &r.attestation {
545 
                let AttestBody::Ref { old_state, new_state, .. } = &sa.attest.body else {
546 
                    return fail("remote sent a non-ref attestation for a bookmark");
547 
                };
548 
                let (old_state, new_state) = (*old_state, *new_state);
549 
                let serial = self
550 
                    .check_ref_attest(sa, &r.name, &old_state, &new_state, self.last_seen_serial(remote_name, &r.name), true)
551 
                    .map_err(|e| RepoError::Msg(format!("attestation for {}/{}: {e}", remote_name, r.name)))?;
552 
                if new_state != r.state {
553 
                    return fail(format!("attestation for {}/{} does not cover its current state", remote_name, r.name));
554 
                }
555 
                let ar = self.store.put_attest(&sa.attest)?;
556 
                for sig in &sa.sigs {
557 
                    self.store.put_signature(&ar, sig)?;
558 
                }
559 
                self.record_serial(remote_name, &r.name, serial)?;
560 
            }
561 
            view.remotes.entry(remote_name.to_string()).or_default().insert(r.name.clone(), state);
562 
            report.push((r.name, r.heads, imported.len()));
563 
        }
564 
        if view != op.view {
565 
            self.record_op(&[op_ref], &format!("oxy fetch {remote_name}"), view)?;
566 
        }
567 
        Ok(FetchReport { refs: report, unverified })
568 
    }
569
570 
    /// Fetch, then take the union of the local bookmark's state with the
571 
    /// remote's: no merge change, conflicts become reified (spec §9.4).
572 
    pub fn pull(&self, remote_name: &str) -> Result<PullReport> {
573 
        self.fetch(remote_name)?;
574 
        let (op_ref, op) = self.head_op()?;
575 
        let bookmark = self.config.bookmark.clone();
576 
        let local = self.heads_of(&op.view, &bookmark)?;
577 
        let Some(remote_state) = op.view.remotes.get(remote_name).and_then(|b| b.get(&bookmark)).copied() else {
578 
            return Ok(PullReport { heads: local, changed: false, checked_out: false });
579 
        };
580 
        let remote_heads = self.store.get_state(&remote_state)?.heads;
581 
        let mut all = local.clone();
582 
        all.extend(remote_heads);
583 
        let st = self.load_state(&all)?;
584 
        let mut heads = st.maximal(&all);
585 
        heads.sort();
586 
        let mut sorted_local = local.clone();
587 
        sorted_local.sort();
588 
        if heads == sorted_local {
589 
            return Ok(PullReport { heads, changed: false, checked_out: false });
590 
        }
591 
        let mut view = op.view.clone();
592 
        view.bookmarks.insert(bookmark.clone(), self.store.put_state(&StateObject::new(heads.clone()))?);
593 
        self.record_op(&[op_ref], &format!("oxy pull {remote_name}"), view)?;
594 
        // Follow along if the working copy was clean and on the old heads.
595 
        let snap = self.snapshot("oxy pull")?;
596 
        let clean = snap.wc.tree_ops.is_empty() && snap.wc.edits.is_empty();
597 
        let mut base = snap.base.maximal(&snap.wc.deps);
598 
        base.sort();
599 
        let mut checked_out = false;
600 
        if clean && base == sorted_local {
601 
            self.checkout(&heads, false, "oxy pull (checkout)")?;
602 
            checked_out = true;
603 
        }
604 
        Ok(PullReport { heads, changed: true, checked_out })
605 
    }
606
607 
    /// Push the current bookmark (spec §16.3), sealing this author's unsigned
608 
    /// changes and attesting the reference when a key is available.
609 
    pub fn push(&self, remote_name: &str, force: bool) -> Result<Vec<RefResult>> {
610 
        let remote = self.open_named_remote(remote_name)?;
611 
        if remote.repo_id()? != self.id()? {
612 
            return fail(format!("remote {remote_name:?} is a different repository (repository IDs differ)"));
613 
        }
614 
        let (op_ref, op) = self.head_op()?;
615 
        let bookmark = self.config.bookmark.clone();
616 
        let local_heads = self.heads_of(&op.view, &bookmark)?;
617 
        let resp = remote.refs()?;
618 
        let local_policy = self.current_policy()?.map(|(_, sp)| sp);
619 
        let policy_to_send = match (&local_policy, &resp.policy) {
620 
            (Some(l), Some(r)) if l.policy.serial > r.policy.serial => Some(l.clone()),
621 
            (Some(l), None) => Some(l.clone()),
622 
            (Some(l), Some(r)) if l.policy.serial < r.policy.serial => {
623 
                return fail(format!("{remote_name} has a newer policy (serial {}); fetch first", r.policy.serial));
624 
            }
625 
            _ => None,
626 
        };
627 
        let remote_has_policy = resp.policy.is_some() || policy_to_send.is_some();
628 
        if remote_has_policy && self.secret_key()?.is_none() {
629 
            return fail(format!("{remote_name} enforces a trust policy; pushing needs an identity (`oxy identity create`)"));
630 
        }
631 
        let refs = resp.refs;
632 
        let empty = self.store.put_state(&StateObject::new(vec![]))?;
633 
        let (remote_state, remote_heads, last_serial) = match refs.iter().find(|r| r.name == bookmark) {
634 
            Some(r) => (r.state, r.heads.clone(), r.last_serial),
635 
            None => (empty, vec![], None),
636 
        };
637 
        let new_state = self.store.put_state(&StateObject::new(local_heads.clone()))?;
638 
        // A push that carries a policy re-attests the bookmark even when its
639 
        // state is unchanged, so the current attestation is always by a key
640 
        // the current policy authorizes (a revoked key's attestation would
641 
        // otherwise be refused by every later fetch).
642 
        if new_state == remote_state && policy_to_send.is_none() {
643 
            return Ok(vec![RefResult { name: bookmark, ok: true, reason: "already up to date".into() }]);
644 
        }
645 
        for h in &remote_heads {
646 
            if !self.store.has(h) {
647 
                return fail(format!("the remote has change {} which you do not; pull first", h.short(12)));
648 
            }
649 
        }
650 
        if !force {
651 
            let closure = self.closure_in_store(&local_heads)?;
652 
            if let Some(h) = remote_heads.iter().find(|h| !closure.contains(h)) {
653 
                return fail(format!("not a fast-forward: remote head {} is not in your state; pull first or use --force", h.short(12)));
654 
            }
655 
        }
656 
        let to_send = self.negotiate(&remote_heads, &local_heads)?;
657 
        let mut bundle = self.bundle_for(&to_send)?;
658 
        let key = self.secret_key()?.map(|(k, _)| k);
659 
        if let Some(key) = key {
660 
            // Seal this author's changes that carry no valid authenticator.
661 
            let mut unsigned = Vec::new();
662 
            for h in &to_send {
663 
                let c = self.store.get_change(h)?;
664 
                if c.author == key && !matches!(self.authenticate_change(h)?, SignatureStatus::Valid { .. }) {
665 
                    unsigned.push(*h);
666 
                }
667 
            }
668 
            for chunk in unsigned.chunks(crate::attest::MAX_SEAL_HASHES) {
669 
                let sa = self.sign_attest(&Attest::seal(self.id()?, chunk.to_vec()))?;
670 
                bundle.attests.push(sa);
671 
            }
672 
            bundle = self.bundle_for(&to_send)?;
673 
        }
674 
        bundle.objects.push((ObjectType::State, StateObject::new(local_heads.clone()).encode()));
675 
        let attestation = match key {
676 
            Some(_) => Some(self.sign_attest(&Attest {
677 
                repo: self.id()?,
678 
                hlc: Hlc::now(),
679 
                body: AttestBody::Ref { name: bookmark.clone(), old_state: remote_state, new_state, serial: last_serial.unwrap_or(0) + 1 },
680 
            })?),
681 
            None => None,
682 
        };
683 
        let serial = attestation.as_ref().and_then(|a| match a.attest.body {
684 
            AttestBody::Ref { serial, .. } => Some(serial),
685 
            _ => None,
686 
        });
687 
        let sent_serial = policy_to_send.as_ref().map(|p| p.policy.serial);
688 
        let results = remote.push(bundle, vec![RefUpdate { name: bookmark.clone(), old_state: remote_state, new_state, force, attestation }], policy_to_send)?;
689 
        if let (Some(serial), true) = (sent_serial, results.iter().any(|r| r.ok && r.name == "policy")) {
690 
            self.record_policy_serial(remote_name, serial)?;
691 
        }
692 
        if results.iter().any(|r| r.ok && r.name == bookmark) {
693 
            let mut view = op.view.clone();
694 
            view.remotes.entry(remote_name.to_string()).or_default().insert(bookmark.clone(), new_state);
695 
            self.record_op(&[op_ref], &format!("oxy push {remote_name}"), view)?;
696 
            if let Some(s) = serial {
697 
                self.record_serial(remote_name, &bookmark, s)?;
698 
            }
699 
        }
700 
        Ok(results)
701 
    }
702
703 
    /// Clone a remote into `dest`: same repository ID, `origin` remote,
704 
    /// bookmark set to the remote's, working copy checked out.
705 
    pub fn clone(url: &str, dest: &Path) -> Result<Repo> {
706 
        Self::clone_with(url, dest, None, &[])
707 
    }
708
709 
    /// Clone, leaving blobs above `max_blob` bytes to be fetched on first
710 
    /// read, and materializing only `sparse` paths (which implies lazy blobs
711 
    /// unless a size is given, so out-of-scope binaries are never fetched).
712 
    pub fn clone_with(url: &str, dest: &Path, max_blob: Option<u64>, sparse: &[String]) -> Result<Repo> {
713 
        let options = RemoteOptions {
714 
            token: std::env::var("OXY_TOKEN").ok(),
715 
            ca: std::env::var("OXY_CA").ok().map(PathBuf::from),
716 
        };
717 
        let remote = open_remote(url, &options)?;
718 
        let id = remote.repo_id()?;
719 
        let mut repo = Repo::init_with_id(dest, id)?;
720 
        repo.config.set("remote.origin.url", url)?;
721 
        if let Some(m) = max_blob {
722 
            repo.config.set("filter.max-blob", &m.to_string())?;
723 
        } else if !sparse.is_empty() {
724 
            repo.config.set("filter.max-blob", "0")?;
725 
        }
726 
        if !sparse.is_empty() {
727 
            repo.config.set("filter.paths", &sparse.join(","))?;
728 
        }
729 
        repo.save_config()?;
730 
        repo.fetch("origin")?;
731 
        let (op_ref, op) = repo.head_op()?;
732 
        let bookmark = repo.config.bookmark.clone();
733 
        if let Some(state) = op.view.remotes.get("origin").and_then(|b| b.get(&bookmark)).copied() {
734 
            let heads = repo.store.get_state(&state)?.heads;
735 
            let mut view = op.view.clone();
736 
            view.bookmarks.insert(bookmark, state);
737 
            repo.record_op(&[op_ref], &format!("oxy clone {url}"), view)?;
738 
            repo.checkout(&heads, false, "oxy clone (checkout)")?;
739 
        }
740 
        Ok(repo)
741 
    }
742 
}