Struct ExplodedCache 

pub struct ExplodedCache { /* private fields */ }

The two pools, one door. Everything that used to call an ExplodedArchive calls this instead; the eager pool is an ExplodedArchive and behaves exactly as it did.

Implementations

impl ExplodedCache

pub fn open(base: &Path, policy: ExplodePolicy, budget: u64) -> Result<Self>

Open both pools at base (…/objects.exploded), adopting whatever lazy segments a previous process left beside it.

pub fn registered(self: Arc<Self>) -> Arc<Self>

Register this cache so a dashboard tick can read every open store’s band without holding a store lock — the same Weak registry crate::progress keeps, for the same reason and with the same sweep.

pub fn root(&self) -> &str

pub fn set_budget(&self, bytes: u64)

The quota, changed live — what the control plane sets when an account’s plan changes. Takes effect at the next rotation; it never refuses a write and never deletes on the caller’s thread.

pub fn set_global_line(&self, bytes: u64)

The process-wide line this cache holds itself to its fair share of. 0 turns the global check off. Tests set it small; production takes default_global_line at open.

pub fn set_disk_line_percent(&self, percent: u64)

The disk line, changed live. 0 turns it off. Takes effect at the next rotation, like the budget.

pub fn pressure_refused_write_backs(&self) -> u64

Write-backs refused while the disk line was latched.

pub fn budget(&self) -> u64

pub fn policy(&self) -> ExplodePolicy

pub fn path(&self) -> &Path

pub fn explode( &self, oid: &[u8], kind: GitObjectKind, payload: &[u8], ) -> Result<()>

The eager write — the indexer’s sink, at push time. Unchanged behaviour: the policy decides, and what it declines is counted as skipped rather than silently dropped.

pub fn explode_at( &self, oid: &[u8], kind: GitObjectKind, mode: Option<u32>, path: Option<&str>, payload: &[u8], ) -> Result<()>

pub fn write_back( &self, oid: &[u8], kind: GitObjectKind, payload: &[u8], cost: ReadCost, ) -> Result<bool>

The lazy write-back — one object a reader has just inflated from the pack, kept for the next reader.

Buffers only: it appends to the newest segment’s in-memory rows and returns. Nothing is written, nothing is fsynced, no eviction runs. The reader that called it has its bytes already and is not made to wait for anybody — Self::maintain does the I/O on the store’s own thread. Two readers racing on one oid is benign: the same bytes are buffered twice and the newest row wins, which is what ExplodedArchive::explode_at already promises.

pub fn maintain(&self) -> Result<u64>

Write down what is buffered, rotate if the newest segment is full, and evict until the pools fit the budget. The whole of the tier’s I/O, on one thread that is nobody’s reader.

Returns the bytes reclaimed, so a caller can log applied output rather than an intention.

pub fn content(&self, oid: &[u8]) -> Result<Option<(GitObjectKind, Vec<u8>)>>

The object’s kind and bytes from either pool, or None — fall back and re-derive, never wrong.

Eager first: it is the smaller table, its index is the one already warm, and under the shipped policy it holds exactly the objects a graph walk asks for. Then the lazy segments newest first, so a re-entered object is found before the stale copy an older segment may still hold.

pub fn has(&self, oid: &[u8]) -> Result<bool>

pub fn name(&self, oid: &[u8]) -> Result<Option<(Option<u32>, Option<String>)>>

pub fn of_kind(&self, kind: GitObjectKind) -> Result<Vec<(Vec<u8>, Vec<u8>)>>

Every oid of one kind, across both pools, newest spelling winning.

The graph fold’s input. Under the shipped policy every commit is in the eager pool, so this is one table’s scan and the lazy segments add nothing — but it unions rather than assuming that, because a store opened under a different policy must still fold a whole graph.

pub fn retain(&self, live: &dyn Fn(&[u8]) -> bool) -> Result<u64>

Retire every oid live rejects — in both pools.

Both, and that is not defensive: a tombstone written only into the eager pool would leave the lazy pool’s row live, content would fall through to it, and a gc’d object would come back by the second door. That is the same defect a_wholly_dead_pack_does_not_come_back_when_the_store_is_reopened found the first time, one pool along.

pub fn drop_cache(&self) -> Result<u64>

repo gc reclaims the cache. Every lazy segment is unlinked; the eager pool keeps its rows, because they are the graph. Returns the bytes that left the filesystem.

pub fn flush(&self) -> Result<()>

pub fn drop_caches(&self)

What the memory watchdog reaches for: every derived, rebuildable structure in every pool.

pub fn rows(&self) -> Result<u64>

pub fn eager_rows(&self) -> Result<u64>

Rows in the EAGER pool only — what adopt_journal compares against the index, because the lazy pool’s size is a function of what has been read and says nothing about whether a pack was absorbed.

pub fn disk_bytes(&self) -> u64

pub fn use_now(&self) -> CacheUse

pub fn note_rederived(&self)

pub fn pread_served(&self) -> u64

pub fn skipped(&self) -> u64

pub fn engine_stats(&self) -> ExplodedStats

The engine-wide counters, summed over both pools, so no caller can tell the two apart by its instruments.

pub fn kick(self: &Arc<Self>)

Start the write-back thread if one is not already running — and return to the reader immediately either way.

Rickard’s law, from the design note: nobody waits. The reader already has its bytes; the append, the fsync, the rotation and the eviction all happen here, on a thread that is nobody’s request. A thread per 4 MiB of write-back rather than a parked thread per store, because a box holding 1 200 open repositories (lane V) cannot afford 1 200 idle threads and can easily afford one spawn per few thousand objects read.

The flag is the whole of the mutual exclusion: a second reader finding it set does nothing, and the running thread loops until the buffer is empty before clearing it, so no work is dropped between the two.

Trait Implementations

impl PayloadSink for ExplodedCache

fn wants(&self, kind: GitObjectKind) -> bool

Will this sink read the payload of an object of this kind?

fn explode(&self, oid: &[u8], kind: GitObjectKind, payload: &[u8]) -> Result<()>

One resolved object: its oid, the type its chain resolves to, and the inflated payload. Called once per pack entry, never for a delta’s intermediate state.

fn flush(&self) -> Result<()>

Write down whatever is buffered. Called by the resolver when the memory watchdog says the box is short (crate::memguard) and at the end of a pack; a sink that buffers nothing has nothing to do.