Two audit-verified caches grew monotonically for process lifetime, which is
fatal for the 30-bot long-uptime headless-fleet goal:
- DatSoundCache._waves (Core) memoized every decoded PCM WaveData forever
in a bare ConcurrentDictionary — no LRU, no byte budget.
- OpenAlAudioEngine._bufferByWaveId (App) retained a native OpenAL buffer
copy of the same PCM per wave id until engine disposal — a second,
independent unbounded cache.
DatSoundCache now bounds payload residency with a 32 MiB byte-budget LRU
(decoded PCM waves run ~100-500 KB each, so this holds a comfortable
working set). Missing/unsupported-format waves are memoized separately in
an unbounded-but-cheap negative-result set (bounded by the finite Wave dat
id space) so they can never compete with or get evicted alongside payload
entries. Concurrent first-touch decodes of the same wave id are deduped
via a shared Lazy<T> so racing callers don't pay for WaveDecoder.Decode
twice. AcDream.Core cannot reference AcDream.Content (code-structure rule
2), so the LRU is a local reimplementation mirroring
BoundedDatObjectCache/DecodedTextureCache's shape rather than a shared
dependency.
OpenAlAudioEngine._bufferByWaveId now bounds native buffer residency with
a 48 MiB byte-budget LRU (AlBufferBudgetTracker), evicting least-recently-
used buffers once oversized. alDeleteBuffers fails on a buffer still
attached to a source, so eviction queries live AL per-source state
(GetSourceInteger.Buffer) rather than tracking a second, easily-stale
copy — several call sites (Play3DWave, PlayUiWave) set a source's buffer
directly. The buffer EnsureBuffer just created is explicitly protected
from its own eviction pass, since the caller hasn't attached it to a
source yet at that point. Evicted waves simply replay through
DatSoundCache -> EnsureBuffer on next use, identical to a first play.
Verified before implementing: AudioHookSink is the only GetWave caller
(single per-frame render-thread path per AnimationHookRouter's own
threading doc), and PcmBytes is read only at DatSoundCache.Admit (byte
accounting) and EnsureBuffer's first-upload branch — confirmed dead after
AL upload on the steady-state replay path, so bounding either cache
independently is correctness-safe; a cold replay after both evict simply
falls back to a full re-decode + re-upload, identical to a first play.
AlBufferBudgetTracker's eviction/budget decision is extracted as pure
logic (no AL dependency) specifically so it's unit-testable: the existing
OpenAlResourceLifetimeTests fake exposes a null AL, which short-circuits
every native buffer call before it runs, so the engine's actual AL wiring
isn't testable headless.
Tests: 9 new DatSoundCacheTests (Core.Tests) covering eviction order, byte
accounting, negative-result memoization, oversize-single-entry handling,
and concurrent-access smoke tests; 10 new AlBufferBudgetTrackerTests
(App.Tests) covering the pure LRU/budget/protection logic. Full suite:
3214/2 skip (Core.Tests), 3471/3 skip (App.Tests) plus one pre-existing,
unrelated failure (LandblockBuildOriginTests.FarLoad_..., reproduces
identically with these changes stashed out — landblock streaming, not
audio).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
(cherry picked from commit 76c880d35bcf30b50e3f7b4cb8635dc9ab9e3ec7)
Erik