address review: shared counted selector budget, 30 s preroll, cache hardening (shared temp roots, matte discard, exact LZ4 length, render version 7), orient nesting guard

crates/render/src/audio.rs

@@ -28,7 +28,7 @@ const MAX_DEPTH: usize = 16;
 const MAX_SPEED: f64 = 100.0;
 
 /// The most effect preroll (history before a block) mixed, in seconds, across a layer's effects.
-const MAX_PREROLL_SECONDS: f64 = 10.0;
+const MAX_PREROLL_SECONDS: f64 = 30.0;
 
 /// The longest footage a waveform summarises (a day).
 const MAX_PEAK_SECONDS: i64 = 24 * 3600;

crates/render/src/disk_cache.rs

@@ -496,17 +496,23 @@ fn make_private(folder: &Path) -> std::io::Result<()> {
     use std::os::unix::fs::PermissionsExt;
     // Judge the folder as written and as it resolves (a relative path, a link or an alias such as
     // /tmp -> /private/tmp can all land in the shared temp folder).
-    let tmp = std::env::temp_dir();
-    let tmp_real = tmp.canonicalize().unwrap_or_else(|_| tmp.clone());
+    // The shared roots: the process's temp folder (`TMPDIR`) and the system's own, which a cache
+    // configured by path lands in whatever `TMPDIR` says.
+    let roots: Vec<PathBuf> = [std::env::temp_dir(), PathBuf::from("/tmp"), PathBuf::from("/var/tmp")]
+        .into_iter()
+        .flat_map(|t| {
+            let real = t.canonicalize().unwrap_or_else(|_| t.clone());
+            [t, real]
+        })
+        .collect();
     let given = std::path::absolute(folder).unwrap_or_else(|_| folder.to_path_buf());
     let real = folder.canonicalize().unwrap_or_else(|_| given.clone());
     // The shared folder itself is not ours to change or to keep a cache in: refused.
-    if [&given, &real].iter().any(|p| **p == tmp || **p == tmp_real) {
+    if [&given, &real].iter().any(|p| roots.contains(p)) {
         return Err(std::io::Error::new(std::io::ErrorKind::PermissionDenied, "the disk cache folder is the shared temp folder"));
     }
     // Only folders inside it are made private.
-    let inside = |p: &PathBuf, t: &PathBuf| p.starts_with(t) && p != t;
-    if ![&given, &real].iter().any(|p| inside(p, &tmp) || inside(p, &tmp_real)) {
+    if ![&given, &real].iter().any(|p| roots.iter().any(|t| p.starts_with(t) && **p != *t)) {
         return Ok(());
     }
     if std::fs::symlink_metadata(folder)?.file_type().is_symlink() {
@@ -1203,8 +1209,12 @@ impl DiskCache {
     /// A segmentation (chain key, scale) written by [`DiskCache::put_seg`].
     pub fn get_seg(&self, key: u64, scale: f64) -> Option<effectcraft_effects::roto::FrameSeg> {
         let p = self.read(Kind::Matte, seg_key(key, scale))?;
-        let raw = decompress_checked(&p, None)?;
-        effectcraft_effects::roto::FrameSeg::from_bytes(&raw)
+        let seg = decompress_checked(&p, None).and_then(|raw| effectcraft_effects::roto::FrameSeg::from_bytes(&raw));
+        if seg.is_none() {
+            // A rejected entry would otherwise stay indexed and keep `put_seg` from replacing it.
+            self.discard(Kind::Matte, seg_key(key, scale));
+        }
+        seg
     }
 
     /// Queue a segmentation for writing.
@@ -1455,7 +1465,8 @@ fn decompress_checked(p: &[u8], expected: Option<usize>) -> Option<Vec<u8>> {
     if size > MAX_ENTRY_BYTES || expected.is_some_and(|e| e != size) {
         return None;
     }
-    lz4_flex::decompress(p.get(4..)?, size).ok()
+    // A block that ends short of the size it states is damaged: callers index by that size.
+    lz4_flex::decompress(p.get(4..)?, size).ok().filter(|raw| raw.len() == size)
 }
 
 fn decode_frame(p: &[u8]) -> Option<Frame8> {
@@ -1565,7 +1576,7 @@ fn decode_layer(p: &[u8]) -> Option<Buf> {
 // ---------------------------------------------------------------- content keys
 
 /// Bump when rendering changes in a way that makes old disk entries wrong.
-const RENDER_VERSION: &str = "effectcraft-render-6";
+const RENDER_VERSION: &str = "effectcraft-render-7";
 
 /// Feeds the `Debug` form of `v` into the hash, followed by a separator byte.
 fn hash_debug(h: &mut Hash128, v: &impl std::fmt::Debug) {
@@ -1685,7 +1696,7 @@ mod tests {
         let dc = DiskCache::open(&d, 1 << 20).unwrap();
         assert_eq!(std::fs::metadata(&d).unwrap().permissions().mode() & 0o777, 0o700);
         drop(dc);
-        let link = tmpdir("link");
+        let link = tmpdir("link-private-temp");
         std::os::unix::fs::symlink(&d, &link).unwrap();
         assert!(DiskCache::open(&link, 1 << 20).is_err());
         let _ = std::fs::remove_file(&link);
@@ -1739,6 +1750,20 @@ mod tests {
         assert_eq!(decode_frame(&ok).map(|f| f.rgba), Some(vec![7; 16]));
     }
 
+    #[test]
+    fn a_block_shorter_than_the_size_it_states_is_rejected() {
+        // The payload states 100 bytes but holds a valid block of 10: `lz4_flex` returns the 10.
+        let mut p = 100u32.to_le_bytes().to_vec();
+        p.extend_from_slice(&lz4_flex::block::compress(&[5u8; 10]));
+        assert!(decompress_checked(&p, None).is_none());
+        // A half-float frame whose planes come up short is refused, not indexed past.
+        let mut f16 = 2u32.to_le_bytes().to_vec();
+        f16.extend_from_slice(&2u32.to_le_bytes());
+        f16.extend_from_slice(&32u32.to_le_bytes());
+        f16.extend_from_slice(&lz4_flex::block::compress(&[1u8; 8]));
+        assert!(decode_frame_f16(&f16).is_none());
+    }
+
     fn tmpdir(name: &str) -> PathBuf {
         let d = std::env::temp_dir().join(format!("effectcraft-disk-cache-{name}-{}", std::process::id()));
         let _ = std::fs::remove_dir_all(&d);

crates/render/src/text.rs

@@ -198,6 +198,35 @@ pub fn in_index_units(layer: &Layer, uid: effectcraft_project::Uid) -> bool {
 
 /// Selection of every glyph by an animator's selectors, per dimension.
 pub fn animator_selection(ctx: &EvalCtx, layer: &Layer, anim: &PropGroup, lay: &TextLayout) -> Vec<[f64; 3]> {
+    animator_selection_within(ctx, layer, anim, lay, &SelectorBudget::new())
+}
+
+/// The Expression Selector evaluations one layer's animators may run in all: counted, not timed,
+/// so the same frame renders the same on every machine.
+pub struct SelectorBudget(std::cell::Cell<usize>);
+
+impl SelectorBudget {
+    pub fn new() -> SelectorBudget {
+        SelectorBudget(std::cell::Cell::new(MAX_SELECTOR_EVALS))
+    }
+
+    /// Take one evaluation; `false` when none are left.
+    fn take(&self) -> bool {
+        let left = self.0.get();
+        self.0.set(left.saturating_sub(1));
+        left > 0
+    }
+}
+
+impl Default for SelectorBudget {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// [`animator_selection`] drawing its Expression Selector evaluations from `budget`, which the
+/// caller shares across the layer's animators.
+pub fn animator_selection_within(ctx: &EvalCtx, layer: &Layer, anim: &PropGroup, lay: &TextLayout, budget: &SelectorBudget) -> Vec<[f64; 3]> {
     let sels: Vec<&PropGroup> = anim.sub("selectors").map(|s| s.groups().filter(|g| g.enabled).collect()).unwrap_or_default();
     if sels.is_empty() {
         // No selectors: every character is fully affected.
@@ -262,17 +291,15 @@ pub fn animator_selection(ctx: &EvalCtx, layer: &Layer, anim: &PropGroup, lay: &
                     ctx.value(layer, prop)
                 }
                 .as_vec3();
-                // One allowance for the whole layer: the expression runs per character, each run
-                // with its own time limit, so a slow expression on a long text is stopped once it
-                // has failed or the layer's evaluations pass MAX_SELECTOR_TIME.
-                let start = web_time::Instant::now();
+                // One allowance for the whole layer (`budget`, shared by its animators): the
+                // expression runs per character, so a slow expression on a long text is stopped
+                // once it has failed or the layer's evaluations pass MAX_SELECTOR_EVALS.
                 let stopped = std::cell::Cell::new(false);
                 Box::new(move |i, n, prev| {
                     let pv = prev.map(|x| x * 100.0);
                     // Without an expression engine: the static amount scales the selection.
                     let fallback = [0, 1, 2].map(|d| stat[d] * prev[d]);
-                    let live = !stopped.get() && start.elapsed() < MAX_SELECTOR_TIME;
-                    let r = match ctx.expr.filter(|_| live && prop.has_expression()) {
+                    let r = match ctx.expr.filter(|_| prop.has_expression() && !stopped.get() && budget.take()) {
                         Some(h) => h.eval_text_selector(ctx, layer, prop, i, n, pv).unwrap_or_else(|_| {
                             stopped.set(true);
                             fallback
@@ -302,15 +329,17 @@ pub fn animator_selection(ctx: &EvalCtx, layer: &Layer, anim: &PropGroup, lay: &
     acc
 }
 
-/// The most time one layer's Expression Selectors may take across all its characters.
-const MAX_SELECTOR_TIME: std::time::Duration = std::time::Duration::from_secs(2);
+/// The most Expression Selector evaluations one layer's animators run across all its characters
+/// (a text of 32,768 characters under one expression selector, or fewer under several).
+const MAX_SELECTOR_EVALS: usize = 32_768;
 /// Evaluate animators for every glyph.
 pub fn char_transforms(ctx: &EvalCtx, layer: &Layer, text: &PropGroup, lay: &TextLayout) -> Vec<CharXf> {
     let mut out = vec![CharXf::default(); lay.glyphs.len()];
     let Some(anims) = text.sub("animators") else { return out };
+    let budget = SelectorBudget::new();
     for anim in anims.groups().filter(|g| g.enabled) {
         let Some(props) = anim.sub("properties") else { continue };
-        let sel = animator_selection(ctx, layer, anim, lay);
+        let sel = animator_selection_within(ctx, layer, anim, lay, &budget);
         let get = |m: &str| props.get(m).map(|p| ctx.value(layer, p).components());
         let get1 = |m: &str| props.get(m).map(|p| ctx.value(layer, p).as_f64());
         let c3 = |v: Vec<f64>, d: f64| [v.first().copied().unwrap_or(d), v.get(1).copied().unwrap_or(d), v.get(2).copied().unwrap_or(d)];

crates/render/src/text/tests.rs

@@ -802,3 +802,12 @@ fn text_notes_the_font_files_it_draws_with() {
     assert!(files.is_complete(), "{files:?}");
     assert_eq!(files.get(&font.to_string_lossy()), Some(stamp), "{files:?}");
 }
+
+#[test]
+fn selector_evaluations_are_counted_across_the_layer_not_timed() {
+    let b = SelectorBudget(std::cell::Cell::new(3));
+    // Taken by any animator's selectors in turn; the fourth finds none, and stays none.
+    assert!([b.take(), b.take(), b.take()].iter().all(|t| *t));
+    assert!(!b.take() && !b.take());
+    assert_eq!(SelectorBudget::new().0.get(), MAX_SELECTOR_EVALS);
+}

crates/render/src/three_d/camera.rs

@@ -350,9 +350,18 @@ pub fn auto_orient_3d(ctx: &EvalCtx, layer: &Layer, pos: Vec3) -> Option<Mat4> {
             if nesting >= MAX_ORIENT_NESTING {
                 return None;
             }
+            // Restored when this scope ends, a panic unwinding through it included (the CPU retry
+            // after one must not start with a raised count).
+            struct Restore(usize);
+            impl Drop for Restore {
+                fn drop(&mut self) {
+                    ORIENT_NESTING.with(|n| n.set(self.0));
+                }
+            }
             ORIENT_NESTING.with(|n| n.set(nesting + 1));
+            let restore = Restore(nesting);
             let parent = parent_world(ctx, layer);
-            ORIENT_NESTING.with(|n| n.set(nesting));
+            drop(restore);
             let eye = active_camera(ctx).eye;
             let e = parent.inverse().unwrap_or(Mat4::IDENTITY).apply(eye);
             let d = pos - e;