OXYGENHUB
# f53cbe7a204e oxygen / crates / oxy-core / src / repo / gc.rs
7.4 KiB · Rust · last changed The issuer countersigns when it accepted a certified update (keyless step 4c) 19 days ago source blame history raw
1 
//! Garbage collection (spec §21): delete objects
2 
//! nothing reachable refers to.
3 
//!
4 
//! Roots: the current view, the views of every operation newer than
5 
//! `core.op-retention`, reference attestations, and the policy; receipts
6 
//! live as long as the changes of their state. Operation
7 
//! objects are always kept so the log stays walkable, but an operation older
8 
//! than the retention window no longer keeps its states alive, so undoing
9 
//! that far back may fail once its objects are gone.
10
11 
use super::*;
12 
use crate::store::{PackReport, PruneReport};
13 
use std::collections::HashSet;
14
15 
#[derive(Debug, Clone, Default, PartialEq, Eq)]
16 
pub struct GcReport {
17 
    pub packed: PackReport,
18 
    pub pruned: PruneReport,
19 
    pub reachable: usize,
20 
    /// Packs folded into the one a full repack writes.
21 
    pub merged_packs: usize,
22 
}
23
24 
impl Repo {
25 
    /// Prune unreachable objects older than the grace period (`now`
26 
    /// ignores it), then repack everything into one pack (spec §13.4).
27 
    pub fn gc(&self, now: bool) -> Result<GcReport> {
28 
        let keep = self.reachable()?;
29 
        let grace = if now {
30 
            std::time::Duration::ZERO
31 
        } else {
32 
            std::time::Duration::from_secs(self.config.gc_grace_days * 86_400)
33 
        };
34 
        let pruned = self.store.prune(&keep, grace)?;
35 
        // Then everything left in one pack, compressed harder than a
36 
        // commit's (spec §13.4), as `git gc` repacks.
37 
        let (packed, merged_packs) = self.store.repack_all(crate::store::REPACK_ZSTD_LEVEL)?;
38 
        Ok(GcReport {
39 
            packed,
40 
            pruned,
41 
            reachable: keep.len(),
42 
            merged_packs,
43 
        })
44 
    }
45
46 
    /// Every object that must survive garbage collection.
47 
    pub fn reachable(&self) -> Result<HashSet<ObjectRef>> {
48 
        let mut keep: HashSet<ObjectRef> = HashSet::new();
49 
        let mut states: Vec<ObjectRef> = Vec::new();
50 
        let mut changes: Vec<ChangeHash> = Vec::new();
51 
        let mut attests: Vec<ObjectRef> = Vec::new();
52 
        let mut policies: Vec<ObjectRef> = Vec::new();
53
54 
        // Operations: always kept; views within retention are roots.
55 
        let cutoff = Hlc::now()
56 
            .wall_ms
57 
            .saturating_sub(self.config.op_retention_days * 86_400_000);
58 
        for (i, (r, op)) in self.op_log()?.into_iter().enumerate() {
59 
            keep.insert(r);
60 
            if i == 0 || op.hlc.wall_ms >= cutoff {
61 
                states.extend(op.view.bookmarks.values().copied());
62 
                states.extend(op.view.remotes.values().flat_map(|b| b.values().copied()));
63 
                changes.extend(op.view.workspaces.values().copied());
64 
                policies.extend(op.view.policy);
65 
            }
66 
        }
67 
        // Checkpoints: the object, its payload blob, and the blob's chunks.
68 
        for r in self.checkpoint_refs()? {
69 
            if let Ok(bytes) = self.store.get_typed(&r, ObjectType::Checkpoint) {
70 
                keep.insert(r);
71 
                let cp = crate::objects::Checkpoint::decode(&bytes)?;
72 
                keep.insert(cp.payload);
73 
                if let Ok(b) = self.store.get_typed(&cp.payload, ObjectType::Blob) {
74 
                    keep.extend(Blob::decode(&b)?.chunks);
75 
                }
76 
                // A version 2 payload's graph blobs and their chunks.
77 
                for g in self.checkpoint_graph_blobs(&cp).unwrap_or_default() {
78 
                    keep.insert(g);
79 
                    if let Ok(b) = self.store.get_typed(&g, ObjectType::Blob) {
80 
                        keep.extend(Blob::decode(&b)?.chunks);
81 
                    }
82 
                }
83 
            }
84 
        }
85 
        // Tags: their states and attestations.
86 
        let view_now = self.view()?;
87 
        states.extend(view_now.tags.values().copied());
88 
        for name in view_now.tags.keys() {
89 
            if let Some((r, _)) = self.tag_attest(name)? {
90 
                attests.push(r);
91 
            }
92 
        }
93 
        // Reference attestations.
94 
        for name in self.view()?.bookmarks.keys() {
95 
            if let Some((r, _)) = self.latest_ref_attest(name)? {
96 
                // With a host's acceptance of it (spec §14.7).
97 
                if let Some(acc) = self.acceptance_of(&r)? {
98 
                    attests.push(acc.attest.hash());
99 
                }
100 
                attests.push(r);
101 
            }
102 
        }
103 
        // A historical view may name objects pruned under an earlier, shorter
104 
        // retention; there is nothing to keep for those.
105 
        for st in states {
106 
            if keep.insert(st) {
107 
                match self.store.get_state(&st) {
108 
                    Ok(s) => changes.extend(s.heads),
109 
                    Err(StoreError::NotFound(_)) => continue,
110 
                    Err(e) => return Err(e.into()),
111 
                }
112 
            }
113 
        }
114 
        for p in policies {
115 
            if keep.insert(p) {
116 
                let bytes = match self.store.get_typed(&p, ObjectType::Policy) {
117 
                    Ok(b) => b,
118 
                    Err(StoreError::NotFound(_)) => continue,
119 
                    Err(e) => return Err(e.into()),
120 
                };
121 
                let policy = crate::policy::Policy::decode(&bytes)?;
122 
                for id in &policy.identities {
123 
                    keep.insert(id.hash());
124 
                }
125 
                for sig in self.store.signatures(&p)? {
126 
                    keep.insert(sig.key);
127 
                }
128 
            }
129 
        }
130 
        // Changes: their closure, identities, blobs, chunks, seals.
131 
        let mut stack = changes;
132 
        while let Some(h) = stack.pop() {
133 
            if !keep.insert(h) {
134 
                continue;
135 
            }
136 
            // Beyond the shallow boundary, or pruned under an earlier
137 
            // retention, there is nothing to keep.
138 
            let c = match self.store.get_change_parts(&h) {
139 
                Ok((c, texts)) => {
140 
                    keep.extend(texts);
141 
                    c
142 
                }
143 
                Err(StoreError::NotFound(_)) => continue,
144 
                Err(e) => return Err(e.into()),
145 
            };
146 
            stack.extend(c.deps.iter().copied());
147 
            if !c.author.is_zero() {
148 
                keep.insert(c.author);
149 
            }
150 
            for sig in self.store.signatures(&h)? {
151 
                self.keep_signer(&mut keep, sig.key)?;
152 
            }
153 
            for e in &c.edits {
154 
                if let Edit::Replace { old, new, .. } = e {
155 
                    for b in [old, new].into_iter().flatten() {
156 
                        if keep.insert(*b) {
157 
                            if let Ok(bytes) = self.store.get_typed(b, ObjectType::Blob) {
158 
                                keep.extend(Blob::decode(&bytes)?.chunks);
159 
                            }
160 
                        }
161 
                    }
162 
                }
163 
            }
164 
            attests.extend(self.store.seals_for(&h)?);
165 
        }
166 
        self.reachable_receipts(&mut keep)?;
167 
        for a in attests {
168 
            if keep.insert(a) {
169 
                for sig in self.store.signatures(&a)? {
170 
                    self.keep_signer(&mut keep, sig.key)?;
171 
                }
172 
            }
173 
        }
174 
        Ok(keep)
175 
    }
176
177 
    /// Keep a signer's identity and, for a short-lived key, its
178 
    /// certificate and the certificate's issuer (spec §14.7).
179 
    pub(crate) fn keep_signer(&self, keep: &mut HashSet<ObjectRef>, key: ObjectRef) -> Result<()> {
180 
        keep.insert(key);
181 
        if let Some(c) = self.store.certificate_of(&key)? {
182 
            keep.insert(c);
183 
            if let Ok(cert) = self.store.get_certificate(&c) {
184 
                keep.insert(cert.cert.issuer);
185 
            }
186 
        }
187 
        Ok(())
188 
    }
189 
}