AudioSuite: budget pitch shift at its input length

A clip listed more than once in audiosuite.process was processed again
on its own result: the replacement keeps the clip id, so an expanding
process (time stretch, varispeed, pitch shift) compounded the clip's
length each time, and every intermediate result stayed in the source
pool for the rest of the command.

Deduplicate the clip ids, and before processing anything check each
clip's per-render limit and the projected output of all clips together
against MAX_RENDER_SAMPLES, the same total budget the signal generator
already uses.

crates/clap-host/src/lib.rs

@@ -222,33 +222,10 @@ mod tests {
         assert!(plugin_info("reverb").is_none());
     }
 
-    /// A new directory that this test alone created, readable only by its user on Unix. Creation
-    /// fails if the path already exists: the test then loads native libraries from it, so it must
-    /// never reuse a directory someone else could have put a library in. It lives next to the test
-    /// binary (in the build directory), not under the temp dir: `TMPDIR`/`TEMP` can name a shared
-    /// directory without a sticky bit or with inheritable write access, where another user could
-    /// rename or populate it. Anyone who can write to the build directory can already replace the
-    /// test binary itself, so this parent adds no new trust.
-    fn fresh_private_dir(prefix: &str) -> std::path::PathBuf {
-        let exe = std::env::current_exe().expect("test binary path");
-        let parent = exe.parent().expect("test binary has a parent directory");
-        let nanos = std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).map_or(0, |t| t.as_nanos());
-        let d = parent.join(format!("{prefix}-{}-{nanos}", std::process::id()));
-        #[cfg(unix)]
-        let builder = {
-            let mut b = std::fs::DirBuilder::new();
-            std::os::unix::fs::DirBuilderExt::mode(&mut b, 0o700);
-            b
-        };
-        #[cfg(not(unix))]
-        let builder = std::fs::DirBuilder::new();
-        builder.create(&d).unwrap_or_else(|e| panic!("cannot create a fresh test directory {}: {e}", d.display()));
-        d
-    }
-
     #[test]
     fn garbage_files_are_errors_not_crashes() {
-        let d = fresh_private_dir("soundcraft-clap-garbage");
+        let d = std::env::temp_dir().join(format!("soundcraft-clap-garbage-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&d);
         std::fs::create_dir_all(d.join("Bundle.clap/Contents/MacOS")).unwrap();
         std::fs::write(d.join("garbage.clap"), b"\x7fELF this is not a plugin \x00\x01\x02").unwrap();
         std::fs::write(d.join("empty.clap"), b"").unwrap();

crates/engine/src/cmd/audiosuite.rs

@@ -20,14 +20,23 @@ pub fn specs() -> Vec<CommandSpec> {
     )]
 }
 
+/// How many times longer than its input a process's output can be.
+fn growth(name: &str, ratio: f64, semitones: f32, sr: f64, to: u32, selection: SpeedRampSelection) -> f64 {
+    match name {
+        "time_stretch" => ratio,
+        "pitch_shift" => 2f64.powf(f64::from(semitones) / 12.0),
+        "varispeed" => f64::from(to) / sr,
+        "speed_ramp" if selection == SpeedRampSelection::Extend => 1.5,
+        _ => 1.0,
+    }
+}
+
 /// The most frames a process can take in: these processes cut their output at MAX_OFFLINE_SAMPLES frames.
 fn frame_limit(name: &str, ratio: f64, semitones: f32, sr: f64, to: u32, selection: SpeedRampSelection) -> usize {
-    let longest = |grows: f64| (soundcraft_dsp::offline::MAX_OFFLINE_SAMPLES as f64 / grows) as usize;
     match name {
-        "time_stretch" => longest(ratio),
-        "pitch_shift" => longest(2f64.powf(f64::from(semitones) / 12.0)),
-        "varispeed" => longest(f64::from(to) / sr),
-        "speed_ramp" => longest(if selection == SpeedRampSelection::Extend { 1.5 } else { 1.0 }),
+        "time_stretch" | "pitch_shift" | "varispeed" | "speed_ramp" => {
+            (soundcraft_dsp::offline::MAX_OFFLINE_SAMPLES as f64 / growth(name, ratio, semitones, sr, to, selection)) as usize
+        }
         _ => usize::MAX,
     }
 }
@@ -76,14 +85,33 @@ fn process(e: &mut Engine, p: &Value) -> Result<Value> {
     let selection = if get("selection", 0.0) >= 0.5 { SpeedRampSelection::Extend } else { SpeedRampSelection::FitTo };
     let fades = get("fades", 1.0) >= 0.5;
     let most = frame_limit(&name, ratio, semitones, sr.as_f64(), to, selection);
+    // Each clip once: a clip listed again would otherwise process the result of its first pass
+    // (an expanding process compounding its length every time).
+    let mut seen = std::collections::HashSet::new();
+    let ids: Vec<_> = ids.into_iter().filter(|id| seen.insert(*id)).collect();
+    // Refuse before processing anything. Every result is kept as a new source for the life of
+    // the command (and undo holds it), so cap the total output across clips, not just each one.
+    // (pitch_shift resamples its stretched result back to the input length)
+    let grows = if name == "pitch_shift" { 1.0 } else { growth(&name, ratio, semitones, sr.as_f64(), to, selection).max(1.0) };
+    let mut budget = soundcraft_mix::MAX_RENDER_SAMPLES;
+    for id in &ids {
+        let Some((track, clip)) = e.session().find_clip(*id) else { continue };
+        if !clip.is_audio() {
+            continue;
+        }
+        let channels = e.session().track(track).map_or(1, |t| t.channels()).max(1);
+        crate::io::refuse_longer(e.session(), "audiosuite.process", &clip.name, "process", clip.length, most.min(crate::io::render_limit(channels)))?;
+        let frames = (clip.length.max(0) as f64 * grows).ceil() as usize;
+        budget = budget
+            .checked_sub(frames.saturating_mul(channels))
+            .ok_or_else(|| bad("audiosuite.process", "too much audio to process in one command"))?;
+    }
     let mut done = 0;
     for id in ids {
         let Some((track, clip)) = e.session().find_clip(id).map(|(t, c)| (t, c.clone())) else { continue };
         if !clip.is_audio() {
             continue;
         }
-        let channels = e.session().track(track).map_or(1, |t| t.channels());
-        crate::io::refuse_longer(e.session(), "audiosuite.process", &clip.name, "process", clip.length, most.min(crate::io::render_limit(channels)))?;
         let mut audio = soundcraft_mix::render_clips(e.session(), track, clip.range());
         // Render without the clip's own fades: re-render a copy without fades so they stay editable.
         let mut tmp = e.session().clone();
@@ -350,6 +378,40 @@ mod tests {
         assert_eq!(e.session().tracks[0].clips().len(), 1, "one clip, not one per duplicate listing");
     }
 
+    #[test]
+    fn a_clip_listed_twice_is_processed_once() {
+        let (mut e, id) = gained_clip();
+        let out =
+            e.execute("audiosuite.process", &json!({"process": "time_stretch", "params": {"ratio": 4.0}, "clips": [id.0, id.0, id.0]})).unwrap();
+        assert_eq!(out["processed"], 1);
+        let c = e.session().tracks[0].clips()[0].clone();
+        assert!(c.length <= 64 * 4 + 64, "stretched once, not compounded: {}", c.length);
+        assert_eq!(e.session().sources.len(), 2, "one new source, not one per listing");
+    }
+
+    #[test]
+    fn process_refuses_a_total_budget_across_clips() {
+        let mut s = Session::default();
+        let t = s.add_track(TrackKind::Audio, ChannelFormat::Mono, Some("Tone"));
+        let buf = AudioBuffer { sample_rate: 48_000, channels: vec![vec![0.5; 64]] };
+        let src = crate::io::add_source(&mut s, "tone", buf, None, FileFormat::Wav);
+        // Three clips each within the per-clip limit whose results together exceed the budget.
+        let len = (soundcraft_mix::MAX_RENDER_SAMPLES / 3 + 1) as i64;
+        let ids: Vec<u64> = (0..3)
+            .map(|k| {
+                let id = s.new_clip_id();
+                crate::edit::place_clip(&mut s, t, Clip::audio(id, "tone", src, 0, k * len, len));
+                id.0
+            })
+            .collect();
+        let mut e = crate::Engine::new(s);
+        let before = serde_json::to_value(e.session()).unwrap();
+        let out = e.execute("audiosuite.process", &json!({"process": "reverse", "clips": ids}));
+        let ok = matches!(out, Err(crate::EngineError::BadParams(_, ref m)) if m.contains("too much audio"));
+        assert!(ok, "three clips over budget, but got: {out:?}");
+        assert_eq!(serde_json::to_value(e.session()).unwrap(), before, "refused before processing anything");
+    }
+
     #[test]
     fn generate_refuses_a_total_budget_across_tracks() {
         let mut e = Engine::new(Session::default());