KeelrLeek
793f78370e
Preview modal audio, five rounds: - True track-change crossfade: scheduleSettle no longer silences the outgoing clip at t=0; preview_load's equal-power fade owns both ramps, gated on the incoming voice's first Playing event (audible_marks), with failure/overstay fallbacks. CROSSFADE_MS = 340 — locked to the reel's card-slide so audio and visuals land together. - Two-neighbour lease prefetch + a 15-min on-disk clip byte-cache (recent_clips): steps in BOTH directions crossfade in ~15 ms; revisits never re-download. - Adaptive settle (isolated steps fire immediately, bursts coalesce) and anticipatory auto-advance (step at clip end minus 400 ms) so auto-play crossfades over the tail instead of gapping. - Session resume memory: revisited tracks continue where they left off (decoder-level start offset via play_local_from/resume_at); finished tracks restart from the top. - Open/close crossfades with the MAIN player: fade-pause with the desired-paused latch landing at ramp end, fade-resume from the paused position; MAIN_FADE_GEN guards; focus handshake relaxation documented in focusBridge. Volume normalization (Settings > Playback, default on): - Dependency-free BS.1770/EBU R128 meter in the player crate (K-weighting, 400 ms gated blocks, incremental) + analyzer that reads the same growing file playback streams from — first plays are measured at download speed. - Gain layered under user volume; audible start GATED on a preliminary measurement (10 s of audio or 800 ms budget) so the level is right from the first sample and never changes mid-track; prelim boosts capped 3 dB, peak-aware clipping guard, persistent loudness-cache.json. - Gapless boundaries get their own sample-accurate gain via SetNextNormGainDb, fed by preload analysis. Debug overlay (Ctrl+Shift+D): process-tree CPU / PDH GPU / working-set + private-commit RAM / network rates / FPS / current-track download progress read from the backend's own StreamProgress / live normalization state / preview session phase. Polls only while visible. 131 JS + player + app tests green; every path verified live over CDP.
891 lines
34 KiB
Rust
891 lines
34 KiB
Rust
//! Preview playback backend — scrollable-track-previews Phase 2.
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//!
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//! A wholly separate audio path from the ordinary player: its own `Player`
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//! instance, its own event channel (`soulstream:preview`), its own bounded
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//! on-disk clip cache. Nothing here touches the queue, history, stream
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//! caches, or the Soulseek resolver — that isolation is the feature's
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//! non-negotiable boundary.
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//!
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//! The resolver contract mirrors `src/lib/preview/resolver.js`: stable track
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//! id in, `{ ok, lease | failure }` out, with the failure classes Phase 0
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//! actually observed. Signed URLs never cross the IPC boundary — the
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//! renderer receives an opaque lease id; bytes live in a temp file the
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//! renderer never sees either.
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use std::collections::HashMap;
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use std::path::PathBuf;
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use std::sync::atomic::{AtomicU32, AtomicU64, AtomicUsize, Ordering};
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use std::sync::{Arc, Mutex};
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use std::time::{Duration, Instant};
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use serde::Serialize;
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use tauri::{Emitter, Manager, State};
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use player::{Player, PlayerEvent};
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use crate::pipeline::LibraryState;
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use crate::playback::PlayerState;
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/// Position events at ~10/s: the modal's canvas scrubber wants smoother
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/// motion than the main bar's 200 ms cadence, and one small window is cheap.
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const PREVIEW_POSITION_INTERVAL: Duration = Duration::from_millis(100);
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/// Fade-engine tick. ~15 ms keeps a 250 ms ramp at 16+ steps — audibly
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/// smooth — while each step is one cheap volume command to the sink.
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const FADE_TICK: Duration = Duration::from_millis(15);
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/// The preview voices' resting volume. The player crate's own default; the
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/// renderer never sets a preview volume today, so fades ramp to this unless
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/// a `volume` control changes the target.
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const DEFAULT_TARGET_VOL: f32 = 0.7;
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/// Lease-lifetime constants, mirroring `src/lib/preview/lease.js` — the two
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/// sides MUST agree or the renderer would trust a lease the backend already
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/// considers dead. Values are ADRs backed by the Phase 0 soak.
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const SAFETY_MARGIN_MS: i64 = 20_000;
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const FALLBACK_SAFE_MS: i64 = 60_000;
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const MAX_SAFE_MS: i64 = 30 * 60_000;
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/// Clip files older than this are swept on init and on each resolve — a
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/// preview session never legitimately needs an hour-old clip.
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const CLIP_MAX_AGE: Duration = Duration::from_secs(60 * 60);
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/// Re-resolving a track whose clip bytes are already on disk skips the
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/// network entirely within this window (the bytes are immutable audio — only
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/// the signed URL goes stale, and a local file needs no URL). This is what
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/// makes stepping BACK to a just-played track as fast as a prefetched
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/// forward step. Kept well under CLIP_MAX_AGE so the sweep can never delete
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/// a file this cache would still hand out.
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const CLIP_REUSE_TTL: Duration = Duration::from_secs(15 * 60);
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/// Two voices, not one: a 250 ms equal-power crossfade between track
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/// previews (user decision 2026-07-23) needs the outgoing and incoming clips
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/// SOUNDING at once, which a single `Player` cannot do. `active` names the
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/// voice whose events reach the UI; the other is either idle or a dying
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/// fade-out tail. Shadow volumes exist because `Player` has no volume
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/// getter and an interrupted fade must hand its partial level to the next
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/// ramp — restarting from the target would audibly bump.
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pub struct PreviewState {
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voices: [Arc<Player>; 2],
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active: Arc<AtomicUsize>,
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/// f32 bits; what fades ramp to and steady playback sits at.
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target_vol: AtomicU32,
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/// f32 bits per voice; the last volume actually commanded.
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shadow_vols: Arc<[AtomicU32; 2]>,
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/// Bumping this orphans every in-flight fade thread (generation guard —
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/// same discipline as the renderer's session reducer).
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fade_gen: Arc<AtomicU64>,
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/// Per-voice counter bumped by the event forwarders on that voice's
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/// Playing events — i.e. a clip actually STARTED SOUNDING there. The
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/// crossfade waits on this before starting its ramps: ramping on the
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/// load command would fade the outgoing into the incoming clip's decode
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/// latency (the mock-derived "ramp on audible, not on play()" trap).
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audible_marks: Arc<[AtomicU64; 2]>,
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/// opaque lease id → clip file. Entries die with the session (dispose)
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/// or the sweep; the map is small by construction (active + prefetch).
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leases: Mutex<HashMap<String, PathBuf>>,
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/// track id → (clip file, fetched at): the CLIP_REUSE_TTL byte cache.
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/// Several leases may point at one file; dispose clears both maps.
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recent_clips: Mutex<HashMap<u64, (PathBuf, Instant)>>,
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clip_dir: PathBuf,
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lease_counter: AtomicU64,
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}
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impl PreviewState {
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fn active_idx(&self) -> usize {
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self.active.load(Ordering::Relaxed)
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}
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fn target(&self) -> f32 {
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f32::from_bits(self.target_vol.load(Ordering::Relaxed))
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}
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fn set_vol(&self, idx: usize, v: f32) {
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self.voices[idx].set_volume(v);
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self.shadow_vols[idx].store(v.to_bits(), Ordering::Relaxed);
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}
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fn shadow(&self, idx: usize) -> f32 {
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f32::from_bits(self.shadow_vols[idx].load(Ordering::Relaxed))
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}
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/// Cancel any running fade and return the new generation.
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fn bump_fades(&self) -> u64 {
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self.fade_gen.fetch_add(1, Ordering::Relaxed) + 1
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}
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}
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/// How long a crossfade waits for the incoming voice to become audible
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/// before ramping anyway. Local-file decode start is tens of ms; hitting
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/// this means the clip is broken (its error event fails the item) and the
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/// outgoing should still fade out rather than play forever.
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const AUDIBLE_WAIT_MAX: Duration = Duration::from_millis(2_000);
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/// One fade thread: equal-power ramp (incoming rides sin, outgoing cos, so
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/// summed acoustic power stays level — a linear fade dips in the middle).
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/// `audible_gate` (marks array, voice, snapshot) holds BOTH ramps until that
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/// voice's mark moves past the snapshot — the incoming clip is genuinely
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/// sounding — so the outgoing keeps playing at level through decode startup
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/// and the cross is a true overlap. Generation-guarded at every tick; at
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/// completion the outgoing voice is STOPPED, not just silent, so a decayed
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/// clip can never linger.
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#[allow(clippy::too_many_arguments)]
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fn spawn_fade(
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gen: u64,
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gen_ctr: Arc<AtomicU64>,
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voices: [Arc<Player>; 2],
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shadows: Arc<[AtomicU32; 2]>,
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fade_in: Option<(usize, f32)>,
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fade_out: Option<(usize, f32)>,
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duration_ms: u64,
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audible_gate: Option<(Arc<[AtomicU64; 2]>, usize, u64)>,
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) {
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let set = move |shadows: &[AtomicU32; 2], voices: &[Arc<Player>; 2], idx: usize, v: f32| {
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voices[idx].set_volume(v);
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shadows[idx].store(v.to_bits(), Ordering::Relaxed);
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};
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std::thread::Builder::new()
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.name("preview-fade".into())
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.spawn(move || {
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if let Some((marks, idx, snapshot)) = &audible_gate {
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let wait0 = Instant::now();
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while marks[*idx].load(Ordering::Relaxed) == *snapshot
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&& wait0.elapsed() < AUDIBLE_WAIT_MAX
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{
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if gen_ctr.load(Ordering::Relaxed) != gen {
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return; // a newer command owns the voices now
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}
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std::thread::sleep(FADE_TICK);
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}
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}
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let t0 = Instant::now();
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loop {
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if gen_ctr.load(Ordering::Relaxed) != gen {
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return; // a newer command owns the voices now
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}
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let t = (t0.elapsed().as_millis() as f32 / duration_ms.max(1) as f32).min(1.0);
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let phase = t * std::f32::consts::FRAC_PI_2;
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if let Some((idx, target)) = fade_in {
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set(&shadows, &voices, idx, target * phase.sin());
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}
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if let Some((idx, from)) = fade_out {
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set(&shadows, &voices, idx, from * phase.cos());
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}
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if t >= 1.0 {
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break;
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}
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std::thread::sleep(FADE_TICK);
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}
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if gen_ctr.load(Ordering::Relaxed) != gen {
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return;
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}
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if let Some((idx, _)) = fade_out {
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voices[idx].stop();
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}
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})
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.expect("spawn preview fade");
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}
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// ------------------------------------------------------------------ init --
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pub fn init(app: &tauri::AppHandle) {
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// Same configured output device as the main player, so previews follow
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// the user's routing. (Device CHANGES while a preview session is open
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// are part of the Phase 2 focus matrix, handled at the coordinator.)
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let output_device = crate::config::load(app).audio_output_device;
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let (p0, events0) = Player::spawn_with_device(output_device.clone());
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let (p1, events1) = Player::spawn_with_device(output_device);
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let clip_dir = app
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.path()
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.app_cache_dir()
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.map(|d| d.join("preview-clips"))
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.unwrap_or_else(|_| std::env::temp_dir().join("soulstream-preview-clips"));
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let _ = std::fs::create_dir_all(&clip_dir);
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sweep_old_clips(&clip_dir);
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let active = Arc::new(AtomicUsize::new(0));
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let audible_marks: Arc<[AtomicU64; 2]> = Arc::new([AtomicU64::new(0), AtomicU64::new(0)]);
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app.manage(PreviewState {
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voices: [Arc::new(p0), Arc::new(p1)],
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active: active.clone(),
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target_vol: AtomicU32::new(DEFAULT_TARGET_VOL.to_bits()),
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shadow_vols: Arc::new([
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AtomicU32::new(DEFAULT_TARGET_VOL.to_bits()),
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AtomicU32::new(DEFAULT_TARGET_VOL.to_bits()),
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]),
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fade_gen: Arc::new(AtomicU64::new(0)),
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audible_marks: audible_marks.clone(),
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leases: Mutex::new(HashMap::new()),
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recent_clips: Mutex::new(HashMap::new()),
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clip_dir,
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lease_counter: AtomicU64::new(1),
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});
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// One forwarder per voice. Only the ACTIVE voice's events reach the UI:
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// after a crossfade handover the dying voice keeps decoding for its fade
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// tail, and its Stopped/Ended must not masquerade as the new clip's.
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for (idx, events) in [(0usize, events0), (1usize, events1)] {
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let handle = app.clone();
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let active = active.clone();
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let audible_marks = audible_marks.clone();
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std::thread::Builder::new()
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.name(format!("preview-events-{idx}"))
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.spawn(move || {
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let mut last_position = Instant::now() - PREVIEW_POSITION_INTERVAL;
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for ev in events {
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// Audible-mark bump happens BEFORE the active filter: it
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// is a per-voice fact the crossfade gate must see even if
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// a later command flipped active away. Playing ONLY — a
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// rapid step can land while this voice still runs an
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// orphaned fade tail, whose Position stream would open
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// the gate before the NEW clip sounds; Playing is emitted
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// exactly once per play start, so it names the new clip.
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if matches!(&ev, PlayerEvent::Playing) {
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audible_marks[idx].fetch_add(1, Ordering::Relaxed);
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}
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if active.load(Ordering::Relaxed) != idx {
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continue;
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}
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let ui = match ev {
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PlayerEvent::Buffering => PreviewUiEvent::Buffering,
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PlayerEvent::Playing => PreviewUiEvent::Playing,
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PlayerEvent::Paused => PreviewUiEvent::Paused,
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PlayerEvent::Stopped => PreviewUiEvent::Stopped,
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PlayerEvent::TrackEnded { .. } => PreviewUiEvent::Ended,
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PlayerEvent::Position { secs, duration } => {
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let now = Instant::now();
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if now.duration_since(last_position) < PREVIEW_POSITION_INTERVAL {
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continue;
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}
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last_position = now;
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PreviewUiEvent::Position { secs, duration }
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}
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PlayerEvent::Error(message) => PreviewUiEvent::Error { message },
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};
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let _ = handle.emit("soulstream:preview", ui);
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}
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})
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.expect("spawn preview event forwarder");
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}
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}
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#[derive(Serialize, Clone)]
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#[serde(tag = "kind", rename_all = "kebab-case")]
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enum PreviewUiEvent {
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Buffering,
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Playing,
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Paused,
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Stopped,
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Ended,
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Position { secs: f64, duration: Option<f64> },
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Error { message: String },
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}
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fn sweep_old_clips(dir: &std::path::Path) {
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let Ok(entries) = std::fs::read_dir(dir) else {
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return;
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};
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for entry in entries.flatten() {
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let stale = entry
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.metadata()
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.and_then(|m| m.modified())
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.map(|t| t.elapsed().unwrap_or_default() > CLIP_MAX_AGE)
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.unwrap_or(true);
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if stale {
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let _ = std::fs::remove_file(entry.path());
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}
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}
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}
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// ------------------------------------------------------------- resolver ---
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#[derive(Serialize)]
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#[serde(rename_all = "camelCase")]
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pub struct PreviewLeaseDto {
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pub opaque_lease_id: String,
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pub safe_for_ms: i64,
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pub byte_length: usize,
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pub mime_type: String,
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/// Hint only; the transport reports the decoder's real duration.
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pub clip_duration_ms: i64,
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}
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#[derive(Serialize)]
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#[serde(rename_all = "camelCase")]
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pub struct PreviewResolveResult {
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pub ok: bool,
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#[serde(skip_serializing_if = "Option::is_none")]
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pub lease: Option<PreviewLeaseDto>,
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#[serde(skip_serializing_if = "Option::is_none")]
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pub failure: Option<&'static str>,
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pub retryable: bool,
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}
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fn fail(failure: &'static str, retryable: bool) -> PreviewResolveResult {
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PreviewResolveResult {
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ok: false,
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lease: None,
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failure: Some(failure),
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retryable,
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}
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}
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/// Resolve a stable Deezer track id into a playable lease. Every call mints
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/// fresh — /track responses carry per-request signed URLs (Phase 0), so a
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/// cached body is a stale lease by construction. The single-retry cap on
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/// failures lives with the caller (renderer), matching the fixture resolver.
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/// Mint a lease over an already-downloaded clip file, if one is fresh enough.
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/// The bytes are immutable; only the signed URL a lease normally rides on can
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/// go stale, and a local file has no URL — so the reuse window is ours to
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/// pick (CLIP_REUSE_TTL). safe_for_ms gets the short fallback: a re-resolve
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/// after it lapses lands right back here and is equally cheap.
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fn mint_from_recent_clip(state: &PreviewState, track_id: u64) -> Option<PreviewResolveResult> {
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let (path, byte_length) = {
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let clips = state.recent_clips.lock().expect("preview clip lock");
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let (path, fetched_at) = clips.get(&track_id)?;
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if fetched_at.elapsed() > CLIP_REUSE_TTL {
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return None;
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}
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let len = std::fs::metadata(path).ok()?.len() as usize;
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(path.clone(), len)
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};
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let nonce = state.lease_counter.fetch_add(1, Ordering::Relaxed);
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let lease_id = format!("pv-{track_id}-{nonce}");
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state
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.leases
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.lock()
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.expect("preview lease lock")
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.insert(lease_id.clone(), path);
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Some(PreviewResolveResult {
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ok: true,
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lease: Some(PreviewLeaseDto {
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opaque_lease_id: lease_id,
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safe_for_ms: FALLBACK_SAFE_MS,
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byte_length,
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mime_type: "audio/mpeg".into(),
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clip_duration_ms: 30_000,
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}),
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failure: None,
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retryable: false,
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})
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}
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#[tauri::command]
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pub async fn preview_resolve(
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library: State<'_, LibraryState>,
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state: State<'_, PreviewState>,
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track_id: u64,
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) -> Result<PreviewResolveResult, String> {
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sweep_old_clips(&state.clip_dir);
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if let Some(cached) = mint_from_recent_clip(&state, track_id) {
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return Ok(cached);
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}
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let Some(body) = library.metadata.deezer_track_uncached(track_id).await else {
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return Ok(fail("network", true));
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};
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if let Some(err) = body.get("error") {
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let class = err.get("type").and_then(|t| t.as_str()).unwrap_or("");
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return Ok(match class {
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// Deezer's 200-with-error-body shapes, from Phase 0.
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"DataException" | "InvalidQueryException" => fail("not_found", false),
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_ => fail("temporarily_failed", true),
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});
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}
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let preview_url = body
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.get("preview")
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.and_then(|p| p.as_str())
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.unwrap_or("")
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.to_string();
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if preview_url.is_empty() {
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return Ok(fail("not_provided", false));
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}
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let media = match metadata::fetch_preview_media(&preview_url).await {
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Ok(m) => m,
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Err(metadata::PreviewFetchError::Status(403)) => return Ok(fail("stale_lease", true)),
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Err(metadata::PreviewFetchError::Status(_)) => return Ok(fail("temporarily_failed", true)),
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Err(metadata::PreviewFetchError::DisallowedUrl) => return Ok(fail("invalid_media", false)),
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Err(metadata::PreviewFetchError::TooLarge) => return Ok(fail("invalid_media", false)),
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Err(metadata::PreviewFetchError::Network) => return Ok(fail("network", true)),
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};
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|
// MIME gate first (the stale-lease body is an HTML error page), then the
|
|
// container transform every Deezer clip needs: skip the universal empty
|
|
// ID3v2.4 shell that crashes the symphonia entry (Phase 0.3), then prove
|
|
// the remainder starts on an MPEG sync before it goes anywhere near a
|
|
// decoder.
|
|
let mime_ok = media
|
|
.content_type
|
|
.as_deref()
|
|
.is_some_and(|m| m.starts_with("audio/mpeg"));
|
|
if !mime_ok {
|
|
return Ok(fail("invalid_media", false));
|
|
}
|
|
let audio = strip_id3v2(&media.bytes);
|
|
if !starts_with_mpeg_sync(audio) {
|
|
return Ok(fail("invalid_media", false));
|
|
}
|
|
|
|
let nonce = state.lease_counter.fetch_add(1, Ordering::Relaxed);
|
|
let lease_id = format!("pv-{track_id}-{nonce}");
|
|
let path = state.clip_dir.join(format!("{lease_id}.mp3"));
|
|
if std::fs::write(&path, audio).is_err() {
|
|
return Ok(fail("temporarily_failed", true));
|
|
}
|
|
state
|
|
.leases
|
|
.lock()
|
|
.expect("preview lease lock")
|
|
.insert(lease_id.clone(), path.clone());
|
|
state
|
|
.recent_clips
|
|
.lock()
|
|
.expect("preview clip lock")
|
|
.insert(track_id, (path, Instant::now()));
|
|
|
|
let safe_for_ms =
|
|
compute_safe_for_ms(parse_exp_ms(&preview_url), media.date_ms, now_epoch_ms());
|
|
|
|
Ok(PreviewResolveResult {
|
|
ok: true,
|
|
lease: Some(PreviewLeaseDto {
|
|
opaque_lease_id: lease_id,
|
|
safe_for_ms,
|
|
byte_length: audio.len(),
|
|
mime_type: "audio/mpeg".into(),
|
|
clip_duration_ms: 30_000,
|
|
}),
|
|
failure: None,
|
|
retryable: false,
|
|
})
|
|
}
|
|
|
|
// ------------------------------------------------------------ transport ---
|
|
|
|
/// Load a resolved clip into the preview player. `start_paused` uses the
|
|
/// desired-paused latch (Phase 0.4): the decoder comes up parked, so opening
|
|
/// against a still-negotiating focus transfer can never leak audio.
|
|
///
|
|
/// `crossfade_ms > 0` (and not paused): the clip lands on the IDLE voice,
|
|
/// which becomes active and ramps 0→target while the old voice ramps down
|
|
/// from wherever it is and stops — the equal-power crossfade. `0`/paused is
|
|
/// the original hard swap on the active voice.
|
|
///
|
|
/// `start_at_secs`: the session's resume memory — the decoder comes up
|
|
/// already positioned there (no play-then-seek race).
|
|
#[tauri::command]
|
|
pub fn preview_load(
|
|
state: State<'_, PreviewState>,
|
|
lease_id: String,
|
|
start_paused: bool,
|
|
crossfade_ms: Option<u64>,
|
|
start_at_secs: Option<f64>,
|
|
) -> Result<(), String> {
|
|
let path = state
|
|
.leases
|
|
.lock()
|
|
.expect("preview lease lock")
|
|
.get(&lease_id)
|
|
.cloned()
|
|
.ok_or("unknown or expired lease")?;
|
|
let gen = state.bump_fades();
|
|
let xfade = crossfade_ms.unwrap_or(0);
|
|
let cur = state.active_idx();
|
|
let target = state.target();
|
|
|
|
if xfade == 0 || start_paused {
|
|
// Hard swap (open, replay, muted, parked): idle voice must be silent
|
|
// — it may be a fade tail a bumped generation just orphaned.
|
|
state.voices[1 - cur].stop();
|
|
state.set_vol(cur, target);
|
|
state.voices[cur].play_local_from(&path, Some(30.0), start_at_secs);
|
|
if start_paused {
|
|
// Ack receipt matters less than the latch being set before any
|
|
// decoder can finish; a timeout here still leaves the latch armed.
|
|
let _ = state.voices[cur]
|
|
.pause_acked()
|
|
.recv_timeout(Duration::from_millis(750));
|
|
}
|
|
return Ok(());
|
|
}
|
|
|
|
let next = 1 - cur;
|
|
let out_from = state.shadow(cur);
|
|
state.set_vol(next, 0.0);
|
|
// Snapshot the incoming voice's audible mark BEFORE play so the fade
|
|
// thread can tell "sounding now" from any earlier life of this voice.
|
|
let mark = state.audible_marks[next].load(Ordering::Relaxed);
|
|
// Active flips BEFORE play so the new voice's Buffering/Playing events
|
|
// are the ones the UI sees; the old voice goes dark mid-fade by design.
|
|
state.active.store(next, Ordering::Relaxed);
|
|
state.voices[next].play_local_from(&path, Some(30.0), start_at_secs);
|
|
spawn_fade(
|
|
gen,
|
|
state.fade_gen.clone(),
|
|
state.voices.clone(),
|
|
state.shadow_vols.clone(),
|
|
Some((next, target)),
|
|
Some((cur, out_from)),
|
|
xfade,
|
|
Some((state.audible_marks.clone(), next, mark)),
|
|
);
|
|
Ok(())
|
|
}
|
|
|
|
#[tauri::command]
|
|
pub fn preview_control(
|
|
state: State<'_, PreviewState>,
|
|
action: String,
|
|
value: Option<f64>,
|
|
) -> Result<(), String> {
|
|
let cur = state.active_idx();
|
|
match action.as_str() {
|
|
"pause" => {
|
|
// Pause silences EVERYTHING: orphan fades, kill any dying tail,
|
|
// and park the active voice back at target so resume is full.
|
|
state.bump_fades();
|
|
state.voices[1 - cur].stop();
|
|
state.voices[cur].pause();
|
|
state.set_vol(cur, state.target());
|
|
}
|
|
"resume" => state.voices[cur].resume(),
|
|
"stop" => {
|
|
state.bump_fades();
|
|
state.voices[0].stop();
|
|
state.voices[1].stop();
|
|
state.set_vol(cur, state.target());
|
|
}
|
|
"seek" => state.voices[cur].seek(value.unwrap_or(0.0)),
|
|
"volume" => {
|
|
let v = value.unwrap_or(DEFAULT_TARGET_VOL as f64) as f32;
|
|
state.target_vol.store(v.to_bits(), Ordering::Relaxed);
|
|
state.set_vol(cur, v);
|
|
}
|
|
// The crossfade's out-half when the incoming clip is not ready yet:
|
|
// ramp the active voice to silence and stop it. The voice STAYS
|
|
// active — its tail events carry a stale generation and die at the
|
|
// renderer's reducer; a later crossfade load flips voices itself.
|
|
"fade_out" => {
|
|
let gen = state.bump_fades();
|
|
state.voices[1 - cur].stop();
|
|
spawn_fade(
|
|
gen,
|
|
state.fade_gen.clone(),
|
|
state.voices.clone(),
|
|
state.shadow_vols.clone(),
|
|
None,
|
|
Some((cur, state.shadow(cur))),
|
|
(value.unwrap_or(250.0) as u64).max(1),
|
|
None,
|
|
);
|
|
}
|
|
other => return Err(format!("unknown preview action {other}")),
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
/// Session teardown: silence the transport and drop every clip file. Safe to
|
|
/// call repeatedly (close, navigation, hot reload all funnel here).
|
|
#[tauri::command]
|
|
pub fn preview_dispose(state: State<'_, PreviewState>) -> Result<(), String> {
|
|
state.bump_fades();
|
|
state.voices[0].stop();
|
|
state.voices[1].stop();
|
|
state.set_vol(0, state.target());
|
|
state.set_vol(1, state.target());
|
|
state
|
|
.recent_clips
|
|
.lock()
|
|
.expect("preview clip lock")
|
|
.clear();
|
|
let mut leases = state.leases.lock().expect("preview lease lock");
|
|
for (_, path) in leases.drain() {
|
|
let _ = std::fs::remove_file(path);
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
// ----------------------------------------------------- main-player ack ----
|
|
|
|
/// Generation guard for MAIN-player fade threads (the session open/close
|
|
/// crossfades). A newer fade command orphans any running one, exactly like
|
|
/// the preview voices' `fade_gen`.
|
|
static MAIN_FADE_GEN: AtomicU64 = AtomicU64::new(0);
|
|
|
|
/// Session-open crossfade, main side: ramp the main player to silence over
|
|
/// `fade_ms` (equal-power cos, so the preview's sin ramp-in sums level),
|
|
/// then pause it WITH the desired-paused latch, then restore `volume` on the
|
|
/// now-silent sink so the later resume has its level back. Returns as soon
|
|
/// as the fade thread is RUNNING — the caller starts the preview's ramp-in
|
|
/// over it; the overlap is the point (deliberate relaxation of the Phase
|
|
/// 0.4 "acknowledged silence before any preview audio" rule, user decision
|
|
/// 2026-07-23). If the ack never lands, the volume stays at 0 — silent is
|
|
/// the safe failure — and the close-side fade-resume self-heals it.
|
|
#[tauri::command]
|
|
pub fn player_fade_pause_acked(
|
|
app: tauri::AppHandle,
|
|
fade_ms: u64,
|
|
volume: f64,
|
|
) -> Result<(), String> {
|
|
let gen = MAIN_FADE_GEN.fetch_add(1, Ordering::Relaxed) + 1;
|
|
std::thread::Builder::new()
|
|
.name("main-fade-out".into())
|
|
.spawn(move || {
|
|
let players = app.state::<PlayerState>();
|
|
let v = volume as f32;
|
|
let dur = fade_ms.max(1);
|
|
let t0 = Instant::now();
|
|
loop {
|
|
if MAIN_FADE_GEN.load(Ordering::Relaxed) != gen {
|
|
return;
|
|
}
|
|
let t = (t0.elapsed().as_millis() as f32 / dur as f32).min(1.0);
|
|
players
|
|
.player
|
|
.set_volume(v * (t * std::f32::consts::FRAC_PI_2).cos());
|
|
if t >= 1.0 {
|
|
break;
|
|
}
|
|
std::thread::sleep(FADE_TICK);
|
|
}
|
|
if MAIN_FADE_GEN.load(Ordering::Relaxed) != gen {
|
|
return;
|
|
}
|
|
let rx = players.player.pause_acked();
|
|
match rx.recv_timeout(Duration::from_millis(1_500)) {
|
|
Ok(_) => players.player.set_volume(v),
|
|
Err(_) => eprintln!("preview: main fade-pause ack timed out; volume left silent"),
|
|
}
|
|
})
|
|
.map_err(|e| e.to_string())?;
|
|
Ok(())
|
|
}
|
|
|
|
/// Session-close crossfade, main side: come back from the paused snapshot at
|
|
/// volume 0 and ramp to `volume` while the preview's fade-out rings down.
|
|
/// Resume also clears the desired-paused latch (player-crate contract).
|
|
#[tauri::command]
|
|
pub fn player_fade_resume(app: tauri::AppHandle, fade_ms: u64, volume: f64) -> Result<(), String> {
|
|
let gen = MAIN_FADE_GEN.fetch_add(1, Ordering::Relaxed) + 1;
|
|
std::thread::Builder::new()
|
|
.name("main-fade-in".into())
|
|
.spawn(move || {
|
|
let players = app.state::<PlayerState>();
|
|
let v = volume as f32;
|
|
players.player.set_volume(0.0);
|
|
players.player.resume();
|
|
let dur = fade_ms.max(1);
|
|
let t0 = Instant::now();
|
|
loop {
|
|
if MAIN_FADE_GEN.load(Ordering::Relaxed) != gen {
|
|
return;
|
|
}
|
|
let t = (t0.elapsed().as_millis() as f32 / dur as f32).min(1.0);
|
|
players
|
|
.player
|
|
.set_volume(v * (t * std::f32::consts::FRAC_PI_2).sin());
|
|
if t >= 1.0 {
|
|
break;
|
|
}
|
|
std::thread::sleep(FADE_TICK);
|
|
}
|
|
})
|
|
.map_err(|e| e.to_string())?;
|
|
Ok(())
|
|
}
|
|
|
|
#[derive(Serialize)]
|
|
#[serde(rename_all = "camelCase")]
|
|
pub struct PauseAckDto {
|
|
pub generation: u64,
|
|
pub sink_was_active: bool,
|
|
pub latched: bool,
|
|
}
|
|
|
|
/// The focus coordinator's silence request against the MAIN player: pause
|
|
/// with a generation-bound acknowledgement (Phase 0.4 primitive). A timeout
|
|
/// is an error — the caller keeps preview parked; it never assumes silence.
|
|
#[tauri::command]
|
|
pub async fn player_pause_acked(players: State<'_, PlayerState>) -> Result<PauseAckDto, String> {
|
|
let rx = players.player.pause_acked();
|
|
tauri::async_runtime::spawn_blocking(move || {
|
|
rx.recv_timeout(Duration::from_millis(1_500))
|
|
.map(|ack| PauseAckDto {
|
|
generation: ack.generation,
|
|
sink_was_active: ack.sink_was_active,
|
|
latched: ack.latched,
|
|
})
|
|
.map_err(|_| "silence acknowledgement timed out".to_string())
|
|
})
|
|
.await
|
|
.map_err(|e| e.to_string())?
|
|
}
|
|
|
|
// ------------------------------------------------------- pure helpers -----
|
|
|
|
fn now_epoch_ms() -> i64 {
|
|
std::time::SystemTime::now()
|
|
.duration_since(std::time::UNIX_EPOCH)
|
|
.map(|d| d.as_millis() as i64)
|
|
.unwrap_or(0)
|
|
}
|
|
|
|
/// `exp=<epoch-seconds>` out of an Akamai `hdnea` token (or bare query).
|
|
fn parse_exp_ms(url: &str) -> Option<i64> {
|
|
let idx = url.find("exp=")?;
|
|
let digits: String = url[idx + 4..]
|
|
.chars()
|
|
.take_while(|c| c.is_ascii_digit())
|
|
.collect();
|
|
if !(9..=11).contains(&digits.len()) {
|
|
return None;
|
|
}
|
|
digits.parse::<i64>().ok().map(|s| s * 1000)
|
|
}
|
|
|
|
/// Mirror of `computeSafeForMs` in src/lib/preview/lease.js — see that file
|
|
/// for the reasoning; the two implementations are kept behaviorally
|
|
/// identical and both covered by tests.
|
|
fn compute_safe_for_ms(exp_ms: Option<i64>, date_ms: Option<i64>, local_now_ms: i64) -> i64 {
|
|
let Some(exp) = exp_ms else {
|
|
return FALLBACK_SAFE_MS;
|
|
};
|
|
if exp <= 0 {
|
|
return FALLBACK_SAFE_MS;
|
|
}
|
|
let mut remaining: Option<i64> = None;
|
|
if let Some(date) = date_ms {
|
|
if date > 0 {
|
|
let r = exp - date;
|
|
if r <= 0 || r > 2 * MAX_SAFE_MS {
|
|
return FALLBACK_SAFE_MS;
|
|
}
|
|
remaining = Some(r);
|
|
}
|
|
}
|
|
let local_view = exp - local_now_ms;
|
|
if local_view <= 0 && remaining.is_none() {
|
|
return FALLBACK_SAFE_MS;
|
|
}
|
|
let usable = match remaining {
|
|
None => local_view,
|
|
Some(r) => {
|
|
if local_view > 0 {
|
|
r.min(local_view)
|
|
} else {
|
|
r
|
|
}
|
|
}
|
|
};
|
|
(usable.min(MAX_SAFE_MS) - SAFETY_MARGIN_MS).max(0)
|
|
}
|
|
|
|
/// Skip a leading ID3v2 tag. Every Phase 0 sample carries a 10-byte v2.4
|
|
/// shell with tag size 0, but the parser handles real non-zero tags too —
|
|
/// the syncsafe size field is authoritative.
|
|
fn strip_id3v2(bytes: &[u8]) -> &[u8] {
|
|
if bytes.len() < 10 || &bytes[0..3] != b"ID3" {
|
|
return bytes;
|
|
}
|
|
let size = ((bytes[6] & 0x7f) as usize) << 21
|
|
| ((bytes[7] & 0x7f) as usize) << 14
|
|
| ((bytes[8] & 0x7f) as usize) << 7
|
|
| (bytes[9] & 0x7f) as usize;
|
|
let end = 10usize.saturating_add(size);
|
|
if end >= bytes.len() {
|
|
return bytes; // tag claims to swallow the file: leave it alone
|
|
}
|
|
&bytes[end..]
|
|
}
|
|
|
|
fn starts_with_mpeg_sync(bytes: &[u8]) -> bool {
|
|
bytes.len() >= 2 && bytes[0] == 0xFF && (bytes[1] & 0xE0) == 0xE0
|
|
}
|
|
|
|
// ------------------------------------------------------------------ tests -
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
const MIN: i64 = 60_000;
|
|
const NOW: i64 = 1_784_760_000_000;
|
|
|
|
#[test]
|
|
fn safe_for_ms_valid_uses_provider_clock() {
|
|
assert_eq!(
|
|
compute_safe_for_ms(Some(NOW + 14 * MIN), Some(NOW), NOW),
|
|
14 * MIN - SAFETY_MARGIN_MS
|
|
);
|
|
}
|
|
|
|
#[test]
|
|
fn safe_for_ms_local_clock_ahead_shrinks() {
|
|
assert_eq!(
|
|
compute_safe_for_ms(Some(NOW + 14 * MIN), Some(NOW), NOW + 10 * MIN),
|
|
4 * MIN - SAFETY_MARGIN_MS
|
|
);
|
|
}
|
|
|
|
#[test]
|
|
fn safe_for_ms_local_clock_behind_cannot_extend() {
|
|
assert_eq!(
|
|
compute_safe_for_ms(Some(NOW + 14 * MIN), Some(NOW), NOW - 60 * MIN),
|
|
14 * MIN - SAFETY_MARGIN_MS
|
|
);
|
|
}
|
|
|
|
#[test]
|
|
fn safe_for_ms_missing_or_contradictory_falls_back() {
|
|
assert_eq!(compute_safe_for_ms(None, Some(NOW), NOW), FALLBACK_SAFE_MS);
|
|
assert_eq!(
|
|
compute_safe_for_ms(Some(NOW - MIN), Some(NOW), NOW),
|
|
FALLBACK_SAFE_MS
|
|
);
|
|
assert_eq!(
|
|
compute_safe_for_ms(Some(NOW + 6 * 60 * MIN), Some(NOW), NOW),
|
|
FALLBACK_SAFE_MS
|
|
);
|
|
}
|
|
|
|
#[test]
|
|
fn exp_parses_from_hdnea_token() {
|
|
let url = "https://cdnt-preview.dzcdn.net/api/x.mp3?hdnea=exp=1784761537~acl=/x*~hmac=aa";
|
|
assert_eq!(parse_exp_ms(url), Some(1_784_761_537_000));
|
|
assert_eq!(parse_exp_ms("https://h/x"), None);
|
|
assert_eq!(parse_exp_ms("https://h/x?exp=12"), None); // too short
|
|
}
|
|
|
|
#[test]
|
|
fn id3_empty_shell_is_skipped() {
|
|
// The exact Phase 0 shape: v2.4 header, flags 0, size 0, then sync.
|
|
let mut f = b"ID3\x04\x00\x00\x00\x00\x00\x00".to_vec();
|
|
f.extend_from_slice(&[0xFF, 0xFB, 0x92, 0x64, 1, 2, 3]);
|
|
let out = strip_id3v2(&f);
|
|
assert!(starts_with_mpeg_sync(out));
|
|
assert_eq!(out.len(), 7);
|
|
}
|
|
|
|
#[test]
|
|
fn id3_nonzero_tag_is_skipped_by_syncsafe_size() {
|
|
let mut f = b"ID3\x03\x00\x00\x00\x00\x00\x0A".to_vec(); // size 10
|
|
f.extend_from_slice(&[0u8; 10]); // tag body
|
|
f.extend_from_slice(&[0xFF, 0xFB, 0x00, 0x00]);
|
|
assert!(starts_with_mpeg_sync(strip_id3v2(&f)));
|
|
}
|
|
|
|
#[test]
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fn id3_overlong_tag_leaves_bytes_untouched() {
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let f = b"ID3\x04\x00\x00\x7f\x7f\x7f\x7f rest".to_vec();
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assert_eq!(strip_id3v2(&f), &f[..]);
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}
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#[test]
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fn plain_frames_pass_through() {
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let f = [0xFF, 0xFB, 0x92, 0x64];
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assert_eq!(strip_id3v2(&f), &f[..]);
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assert!(starts_with_mpeg_sync(&f));
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assert!(!starts_with_mpeg_sync(b"<HTML>"));
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}
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}
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