feat(crucible): keep every captured take

With Keep takes on (default), each capture is written to
<folder>/takes/ as a WAV named by time, tempo and length, so a take
is not lost when the next capture replaces it. Files are never
overwritten: a clash gets a numbered suffix. Saving runs off the UI
thread and the status line shows the path or the error.

plugins/crucible/core/src/export.rs

@@ -34,6 +34,52 @@ pub fn stamp(unix: u64) -> String {
     )
 }
 
+/// Writes a captured take's loop to `root/takes/` right away, so it survives a reload or a
+/// crash. Never overwrites: a name already taken gets a counter. Returns the file written.
+pub fn save_take(take: &Take, root: &Path, unix: u64) -> std::io::Result<PathBuf> {
+    let folder = root.join("takes");
+    std::fs::create_dir_all(&folder)?;
+    let base = format!(
+        "{}_{:.0}bpm_{}bar{}",
+        stamp(unix),
+        take.tempo(),
+        take.bars,
+        if take.bars == 1 { "" } else { "s" }
+    );
+    let wave = wav::Wave {
+        channels: 2,
+        rate: take.rate.round() as u32,
+        samples: take.audio.clone(),
+        root: None,
+        frame: None,
+    };
+    let bytes = wav::encode(&wave);
+    for n in 1..1000 {
+        let name = if n == 1 {
+            format!("{base}.wav")
+        } else {
+            format!("{base}_{n}.wav")
+        };
+        let path = folder.join(name);
+        match std::fs::OpenOptions::new()
+            .write(true)
+            .create_new(true)
+            .open(&path)
+        {
+            Ok(mut file) => {
+                std::io::Write::write_all(&mut file, &bytes)?;
+                return Ok(path);
+            }
+            Err(e) if e.kind() == std::io::ErrorKind::AlreadyExists => continue,
+            Err(e) => return Err(e),
+        }
+    }
+    Err(std::io::Error::new(
+        std::io::ErrorKind::AlreadyExists,
+        "too many takes with the same name",
+    ))
+}
+
 pub fn export(
     take: &Take,
     settings: &Settings,

plugins/crucible/core/src/lib.rs

@@ -5,7 +5,7 @@ mod player;
 mod ring;
 mod settings;
 mod take;
-pub use export::{export, stamp, Exported};
+pub use export::{export, save_take, stamp, Exported};
 pub use player::{Clip, Player, Queues};
 pub use ring::{Marker, Recorder, Ring, Transport, MARKERS};
 pub use settings::{default_folder, Division, Mode, Settings};

plugins/crucible/core/src/settings.rs

@@ -64,6 +64,8 @@ pub struct Settings {
     pub trim: bool,
     /// Also write a wavetable from the selected slice.
     pub wavetable: bool,
+    /// Save every captured take's loop to the `takes` subfolder at once.
+    pub keep_takes: bool,
     /// Export folder; empty selects the default.
     pub folder: String,
 }
@@ -78,6 +80,7 @@ impl Default for Settings {
             normalize: true,
             trim: true,
             wavetable: false,
+            keep_takes: true,
             folder: String::new(),
         }
     }

plugins/crucible/core/tests/core.rs

@@ -231,6 +231,21 @@ fn export_writes_loop_slices_and_wavetable() {
     std::fs::remove_dir_all(&dir).unwrap();
 }
 
+#[test]
+fn save_take_writes_the_loop_and_never_overwrites() {
+    let dir = std::env::temp_dir().join(format!("crucible-takes-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    let mut saw = Saw::new(RATE, 55.);
+    let take = take_of((0..96000).map(|_| saw.sample() * 0.5).collect(), 120., 1);
+    let first = save_take(&take, &dir, 1_700_000_000).unwrap();
+    let second = save_take(&take, &dir, 1_700_000_000).unwrap();
+    assert!(first.ends_with("takes/2023-11-14_221320_120bpm_1bar.wav"));
+    assert!(second.ends_with("takes/2023-11-14_221320_120bpm_1bar_2.wav"));
+    let w = wav::decode(&std::fs::read(&first).unwrap()).unwrap();
+    assert_eq!(w.samples, take.audio);
+    std::fs::remove_dir_all(&dir).unwrap();
+}
+
 #[test]
 fn audition_plays_and_returns_clips_for_freeing() {
     let q = Queues::default();

plugins/crucible/ui/src/lib.rs

@@ -1,8 +1,8 @@
 //! Crucible editor, shared by the CLAP wrapper and the headless renderer.
 use common_ui::*;
 use crucible_core::{
-    capture, export, render, Division, Exported, Mode, Queues, Ring, Settings, Take, Transport,
-    OVERVIEW,
+    capture, export, render, save_take, Division, Exported, Mode, Queues, Ring, Settings, Take,
+    Transport, OVERVIEW,
 };
 use egui::{self, Color32, FontId, Pos2, Rect, RichText, Sense, Stroke, Vec2};
 use std::sync::{Arc, Mutex};
@@ -33,6 +33,8 @@ pub struct State {
     names: Vec<String>,
     /// Filled by the export thread when it finishes.
     job: Option<Arc<Mutex<Option<std::io::Result<Exported>>>>>,
+    /// Filled by the take-saving thread when it finishes.
+    saving: Option<Arc<Mutex<Option<std::io::Result<std::path::PathBuf>>>>>,
     last_export: Option<std::path::PathBuf>,
 }
 impl Default for State {
@@ -49,6 +51,7 @@ impl Default for State {
             counter: 0,
             names: Vec::new(),
             job: None,
+            saving: None,
             last_export: None,
         }
     }
@@ -136,6 +139,17 @@ pub fn show(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State, link:
             Err(e) => format!("Export failed: {e}"),
         };
     }
+    let saved = state
+        .saving
+        .as_ref()
+        .and_then(|job| job.lock().ok().and_then(|mut slot| slot.take()));
+    if let Some(result) = saved {
+        state.saving = None;
+        state.status += &match result {
+            Ok(path) => format!(" Saved {}", path.display()),
+            Err(e) => format!(" Saving the take failed: {e}"),
+        };
+    }
     ui.add_space(2.);
     header(ui, "CRUCIBLE", "RESAMPLER", |ui| {
         let db = 20. * state.peak.max(1e-6).log10();
@@ -204,6 +218,19 @@ fn capture_row(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State, li
             match capture(ring, settings.bars) {
                 Ok(take) => {
                     let synced = take.synced;
+                    if settings.keep_takes {
+                        let slot = Arc::new(Mutex::new(None));
+                        let done = slot.clone();
+                        let take = take.clone();
+                        let folder = settings.folder();
+                        std::thread::spawn(move || {
+                            let result = save_take(&take, &folder, unix_now());
+                            if let Ok(mut slot) = done.lock() {
+                                *slot = Some(result);
+                            }
+                        });
+                        state.saving = Some(slot);
+                    }
                     state.add(take, settings);
                     state.status = if synced {
                         format!("Captured {} bars on the bar grid.", settings.bars)
@@ -481,6 +508,15 @@ fn controls(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State, link:
             state,
             "Also write wavetable.wav from the selected slice: 2048-sample frames for Serum or Vital.",
         );
+        let r = chip(ui, settings.keep_takes, "KEEP TAKES");
+        if r.clicked() {
+            settings.keep_takes = !settings.keep_takes;
+        }
+        hint(
+            &r,
+            state,
+            "Save every capture's loop to the takes folder at once, so a reload or crash loses nothing.",
+        );
         ui.separator();
         let take = state.take;
         let slice = state.slice;