acdream/src/AcDream.Core/Audio/DatSoundCache.cs
Erik f7aa8e0eb7
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fix: complete retail parity stability pass
2026-08-28 20:01:39 +02:00

301 lines
9.9 KiB
C#

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Threading;
using DatReaderWriter;
using DatReaderWriter.DBObjs;
using AcDream.Core.Content;
namespace AcDream.Core.Audio;
public readonly record struct DatSoundCacheDiagnostics(
int CachedWaveCount,
long ResidentWaveBytes,
long BudgetBytes,
long Hits,
long Misses,
long Evictions);
/// <summary>
/// DatCollection-backed cache of decoded waves + SoundTable lookups.
///
/// <para>
/// Lazy-loads each Wave / SoundTable on first request, decodes Wave PCM
/// data via <see cref="WaveDecoder"/>, and memoizes the result. Safe to
/// call from any thread.
/// </para>
///
/// <para>
/// Decoded-wave residency is bounded by a byte budget
/// (<see cref="DefaultMaxWaveBytes"/>, 32 MiB) enforced with an LRU. This
/// mirrors <c>AcDream.Content.BoundedDatObjectCache</c> /
/// <c>DecodedTextureCache</c>'s shape but is reimplemented locally: Code
/// Structure Rule 2 forbids <c>AcDream.Core</c> from referencing
/// <c>AcDream.Content</c>. Decoded PCM waves run roughly 100-500 KB each
/// (a few seconds of 16-bit mono/stereo audio at typical AC sample
/// rates), so a 32 MiB budget comfortably holds 64-320 resident waves —
/// the working set for a play session — without growing without bound
/// over a long-uptime process (the 30-bot headless-fleet target cares
/// about exactly this).
/// </para>
///
/// <para>
/// Waves that can't be served (missing from the dats, or a format
/// <see cref="WaveDecoder"/> doesn't support yet — MP3 / ADPCM currently
/// decode to null) are remembered in a separate negative-result set that
/// is intentionally left unbounded: a bare wave id costs a handful of
/// bytes, and the id space is finite (the Wave dat range holds on the
/// order of a few thousand entries in retail), so it can never grow
/// without bound and it never competes with the payload LRU for budget
/// or gets evicted by it.
/// </para>
///
/// <para>
/// Thread-safety: <see cref="GetWave"/> may be called concurrently.
/// Concurrent first-touch requests for the same wave id share one
/// <see cref="WaveDecoder.Decode"/> call instead of racing duplicate
/// decode work.
/// </para>
/// </summary>
public sealed class DatSoundCache
{
/// <summary>
/// Byte budget for resident decoded-wave payloads. See the class
/// remarks for the ~100-500 KB per-wave sizing rationale.
/// </summary>
internal const long DefaultMaxWaveBytes = 32L * 1024 * 1024; // 32 MiB
private readonly IDatObjectSource _dats;
private readonly ConcurrentDictionary<uint, SoundTable?> _tables = new();
// Negative-result memo (missing wave / unsupported format). Unbounded
// by design — see class remarks — and never evicted by the payload LRU.
private readonly ConcurrentDictionary<uint, byte> _negativeWaveIds = new();
// Dedupes concurrent first-touch decodes of the same wave id so two
// racing callers don't both pay for WaveDecoder.Decode.
private readonly ConcurrentDictionary<uint, Lazy<WaveData?>> _inflight = new();
// Payload LRU: resident decoded waves, bounded by _maxWaveBytes.
private readonly object _gate = new();
private readonly Dictionary<uint, LinkedListNode<WaveEntry>> _waveEntries = new();
private readonly LinkedList<WaveEntry> _waveLru = new();
private readonly long _maxWaveBytes;
private readonly Action<uint>? _afterInitialWaveMiss;
private long _residentWaveBytes;
private long _hits;
private long _misses;
private long _evictions;
private sealed record WaveEntry(uint WaveId, WaveData Wave, long Bytes);
public DatSoundCache(IDatObjectSource dats)
: this(dats, DefaultMaxWaveBytes)
{
}
/// <summary>
/// Test seam for pinning a smaller byte budget so eviction can be
/// exercised deterministically without allocating tens of megabytes.
/// </summary>
public DatSoundCache(IDatObjectSource dats, long maxWaveBytes)
: this(dats, maxWaveBytes, afterInitialWaveMiss: null)
{
}
/// <summary>
/// Deterministic concurrency seam used to park a caller after its fast
/// resident lookup but before the authoritative locked recheck.
/// </summary>
internal DatSoundCache(
IDatObjectSource dats,
long maxWaveBytes,
Action<uint>? afterInitialWaveMiss)
{
ArgumentNullException.ThrowIfNull(dats);
ArgumentOutOfRangeException.ThrowIfLessThan(maxWaveBytes, 1);
_dats = dats;
_maxWaveBytes = maxWaveBytes;
_afterInitialWaveMiss = afterInitialWaveMiss;
}
/// <summary>
/// Retrieve decoded PCM data for a Wave dat id. Returns null if the
/// wave is missing, malformed, or uses a currently-unsupported format
/// (MP3 / ADPCM).
/// </summary>
public WaveData? GetWave(uint waveId)
{
lock (_gate)
{
if (_waveEntries.TryGetValue(waveId, out var node))
{
Interlocked.Increment(ref _hits);
Touch(node);
return node.Value.Wave;
}
}
if (_negativeWaveIds.ContainsKey(waveId))
{
Interlocked.Increment(ref _hits);
return null;
}
_afterInitialWaveMiss?.Invoke(waveId);
Lazy<WaveData?> lazy;
lock (_gate)
{
// A caller can pause after the fast miss while another caller
// decodes, admits, and removes the in-flight Lazy. Recheck the
// authoritative caches and acquire/create the Lazy under the same
// gate used by admission so that stale caller cannot start a
// second decode after publication.
if (_waveEntries.TryGetValue(waveId, out var node))
{
Interlocked.Increment(ref _hits);
Touch(node);
return node.Value.Wave;
}
if (_negativeWaveIds.ContainsKey(waveId))
{
Interlocked.Increment(ref _hits);
return null;
}
Interlocked.Increment(ref _misses);
lazy = _inflight.GetOrAdd(
waveId,
static (id, self) => new Lazy<WaveData?>(
() => self.DecodeUncached(id),
LazyThreadSafetyMode.ExecutionAndPublication),
this);
}
try
{
WaveData? decoded = lazy.Value;
if (decoded is null)
{
_negativeWaveIds.TryAdd(waveId, 0);
return null;
}
return Admit(waveId, decoded);
}
finally
{
_inflight.TryRemove(new KeyValuePair<uint, Lazy<WaveData?>>(waveId, lazy));
}
}
/// <summary>
/// Retrieve a SoundTable by dat id. Returns null if the table is
/// missing from the dats.
/// </summary>
public SoundTable? GetSoundTable(uint soundTableId)
{
if (_tables.TryGetValue(soundTableId, out var cached)) return cached;
var table = _dats.Get<SoundTable>(soundTableId);
_tables[soundTableId] = table;
return table;
}
/// <summary>
/// Number of decoded waves currently resident in the payload LRU.
/// Diagnostic use only.
/// </summary>
public int CachedWaveCount
{
get { lock (_gate) return _waveEntries.Count; }
}
/// <summary>
/// Estimated bytes currently resident in the payload LRU. Diagnostic
/// use only.
/// </summary>
public long ResidentWaveBytes
{
get { lock (_gate) return _residentWaveBytes; }
}
/// <summary>
/// Total number of SoundTables that have been accessed.
/// </summary>
public int CachedSoundTableCount => _tables.Count;
public DatSoundCacheDiagnostics Diagnostics
{
get
{
lock (_gate)
{
return new DatSoundCacheDiagnostics(
_waveEntries.Count,
_residentWaveBytes,
_maxWaveBytes,
Interlocked.Read(ref _hits),
Interlocked.Read(ref _misses),
Interlocked.Read(ref _evictions));
}
}
}
private WaveData? DecodeUncached(uint waveId)
{
var wave = _dats.Get<Wave>(waveId);
if (wave is null) return null;
return WaveDecoder.Decode(wave.Header, wave.Data);
}
private WaveData Admit(uint waveId, WaveData wave)
{
long bytes = Math.Max(1L, (long)wave.PcmBytes.Length);
lock (_gate)
{
// Another caller may have already admitted this id (both
// shared the same in-flight decode and both reach Admit).
if (_waveEntries.TryGetValue(waveId, out var existing))
{
Touch(existing);
return existing.Value.Wave;
}
if (bytes > _maxWaveBytes)
{
// Larger than the entire budget: serve it but don't retain
// it — matches BoundedDatObjectCache's oversize handling.
return wave;
}
while (_waveLru.First is { } oldest
&& _residentWaveBytes + bytes > _maxWaveBytes)
{
Evict(oldest);
}
var node = _waveLru.AddLast(new WaveEntry(waveId, wave, bytes));
_waveEntries[waveId] = node;
_residentWaveBytes += bytes;
return wave;
}
}
private void Touch(LinkedListNode<WaveEntry> node)
{
if (!ReferenceEquals(node, _waveLru.Last))
{
_waveLru.Remove(node);
_waveLru.AddLast(node);
}
}
private void Evict(LinkedListNode<WaveEntry> node)
{
_waveLru.Remove(node);
_waveEntries.Remove(node.Value.WaveId);
_residentWaveBytes -= node.Value.Bytes;
Interlocked.Increment(ref _evictions);
}
}