OXYGENHUB
# e8b4e156f2fa oxygen / crates / oxy-core / src / repo / gc.rs
4.2 KiB · Rust · last changed Garbage collection: operation-log retention, pruning with grace period, pack rewriting; oxy gc --now 1 month ago source blame history raw
1 
//! Garbage collection (spec §21): pack loose objects, then 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. Operation
6 
//! objects are always kept so the log stays walkable, but an operation older
7 
//! than the retention window no longer keeps its states alive, so undoing
8 
//! that far back may fail once its objects are gone.
9
10 
use super::*;
11 
use crate::store::{PackReport, PruneReport};
12 
use std::collections::HashSet;
13
14 
#[derive(Debug, Clone, Default, PartialEq, Eq)]
15 
pub struct GcReport {
16 
    pub packed: PackReport,
17 
    pub pruned: PruneReport,
18 
    pub reachable: usize,
19 
}
20
21 
impl Repo {
22 
    /// Pack loose objects and prune unreachable ones older than the grace
23 
    /// period (`now` ignores the grace period).
24 
    pub fn gc(&self, now: bool) -> Result<GcReport> {
25 
        let packed = self.store.pack_loose()?;
26 
        let keep = self.reachable()?;
27 
        let grace = if now { std::time::Duration::ZERO } else { std::time::Duration::from_secs(self.config.gc_grace_days * 86_400) };
28 
        let pruned = self.store.prune(&keep, grace)?;
29 
        Ok(GcReport { packed, pruned, reachable: keep.len() })
30 
    }
31
32 
    /// Every object that must survive garbage collection.
33 
    pub fn reachable(&self) -> Result<HashSet<ObjectRef>> {
34 
        let mut keep: HashSet<ObjectRef> = HashSet::new();
35 
        let mut states: Vec<ObjectRef> = Vec::new();
36 
        let mut changes: Vec<ChangeHash> = Vec::new();
37 
        let mut attests: Vec<ObjectRef> = Vec::new();
38 
        let mut policies: Vec<ObjectRef> = Vec::new();
39
40 
        // Operations: always kept; views within retention are roots.
41 
        let cutoff = Hlc::now().wall_ms.saturating_sub(self.config.op_retention_days * 86_400_000);
42 
        for (i, (r, op)) in self.op_log()?.into_iter().enumerate() {
43 
            keep.insert(r);
44 
            if i == 0 || op.hlc.wall_ms >= cutoff {
45 
                states.extend(op.view.bookmarks.values().copied());
46 
                states.extend(op.view.remotes.values().flat_map(|b| b.values().copied()));
47 
                changes.extend(op.view.workspaces.values().copied());
48 
                policies.extend(op.view.policy);
49 
            }
50 
        }
51 
        // Reference attestations.
52 
        for name in self.view()?.bookmarks.keys() {
53 
            if let Some((r, _)) = self.latest_ref_attest(name)? {
54 
                attests.push(r);
55 
            }
56 
        }
57 
        for st in states {
58 
            if keep.insert(st) {
59 
                changes.extend(self.store.get_state(&st)?.heads);
60 
            }
61 
        }
62 
        for p in policies {
63 
            if keep.insert(p) {
64 
                let policy = crate::policy::Policy::decode(&self.store.get_typed(&p, ObjectType::Policy)?)?;
65 
                for id in &policy.identities {
66 
                    keep.insert(id.hash());
67 
                }
68 
                for sig in self.store.signatures(&p)? {
69 
                    keep.insert(sig.key);
70 
                }
71 
            }
72 
        }
73 
        // Changes: their closure, identities, blobs, chunks, seals.
74 
        let mut stack = changes;
75 
        while let Some(h) = stack.pop() {
76 
            if !keep.insert(h) {
77 
                continue;
78 
            }
79 
            let c = self.store.get_change(&h)?;
80 
            stack.extend(c.deps.iter().copied());
81 
            if !c.author.is_zero() {
82 
                keep.insert(c.author);
83 
            }
84 
            for sig in self.store.signatures(&h)? {
85 
                keep.insert(sig.key);
86 
            }
87 
            for e in &c.edits {
88 
                if let Edit::Replace { old, new, .. } = e {
89 
                    for b in [old, new].into_iter().flatten() {
90 
                        if keep.insert(*b) {
91 
                            if let Ok(bytes) = self.store.get_typed(b, ObjectType::Blob) {
92 
                                keep.extend(Blob::decode(&bytes)?.chunks);
93 
                            }
94 
                        }
95 
                    }
96 
                }
97 
            }
98 
            attests.extend(self.store.seals_for(&h)?);
99 
        }
100 
        for a in attests {
101 
            if keep.insert(a) {
102 
                for sig in self.store.signatures(&a)? {
103 
                    keep.insert(sig.key);
104 
                }
105 
            }
106 
        }
107 
        Ok(keep)
108 
    }
109 
}