address review: share one clip-work allowance between fill and stroke

crates/engine/src/file_access.rs

@@ -85,20 +85,14 @@ impl AutomationRoots {
 
     /// May the file or folder at `path` be read (or written)? `Err` says why not.
     pub fn check(&self, path: &str, access: Access) -> Result<(), String> {
-        self.check_path(Path::new(path), access)
-    }
-
-    /// [`Self::check`] for a path that may not be UTF-8: the checked path is the one opened.
-    pub fn check_path(&self, path: &Path, access: Access) -> Result<(), String> {
-        let path_text = path.display();
         let roots = match access {
             Access::Read => &self.read,
             Access::Write => &self.write,
         };
         if roots.is_empty() {
             return match access {
-                Access::Read => Err(format!("automation filesystem access is not granted: read authority is absent: {path_text}")),
+                Access::Read => Err(format!("automation filesystem access is not granted: read authority is absent: {path}")),
-                Access::Write => Err(format!("automation filesystem access is not granted: write authority is absent: {path_text}")),
+                Access::Write => Err(format!("automation filesystem access is not granted: write authority is absent: {path}")),
             };
         }
         let resolved = resolve(path)?;
@@ -107,8 +101,8 @@ impl AutomationRoots {
         }
         let roots = roots.iter().map(|root| root.shown.display().to_string()).collect::<Vec<_>>().join(", ");
         match access {
-            Access::Read => Err(format!("automation path rejected: outside the read roots {roots}: {path_text}")),
+            Access::Read => Err(format!("automation path rejected: outside the read roots {roots}: {path}")),
-            Access::Write => Err(format!("automation path rejected: outside the write roots {roots}: {path_text}")),
+            Access::Write => Err(format!("automation path rejected: outside the write roots {roots}: {path}")),
         }
     }
 }
@@ -197,23 +191,17 @@ pub fn check_write(path: &str) -> Result<(), String> {
     current().map_or(Ok(()), |r| r.check(path, Access::Write))
 }
 
-/// May `path` be written here? Always, without roots in force. For a path that may not be UTF-8.
-pub fn check_write_path(path: &Path) -> Result<(), String> {
-    current().map_or(Ok(()), |r| r.check_path(path, Access::Write))
-}
-
 /// `path` made absolute with its links followed; for a path that doesn't exist (yet), its nearest
 /// existing folder's links followed and the rest appended.
-fn resolve(path: &Path) -> Result<PathBuf, String> {
+fn resolve(path: &str) -> Result<PathBuf, String> {
-    if path.as_os_str().is_empty() {
+    if path.is_empty() {
         return Err("automation path rejected: path is empty".into());
     }
-    let shown = path.display();
     // Checked as given: making `…\NUL` absolute gives the device path `\\.\NUL` on Windows.
-    if cfg!(windows) && path.components().any(|c| matches!(c, Component::Normal(n) if is_device_name(&n.to_string_lossy()))) {
+    if cfg!(windows) && Path::new(path).components().any(|c| matches!(c, Component::Normal(n) if is_device_name(&n.to_string_lossy()))) {
-        return Err(format!("automation path rejected: reserved device names are not allowed: {shown}"));
+        return Err(format!("automation path rejected: reserved device names are not allowed: {path}"));
     }
-    let absolute = std::path::absolute(path).map_err(|e| format!("automation path rejected: cannot resolve {shown}: {e}"))?;
+    let absolute = std::path::absolute(path).map_err(|e| format!("automation path rejected: cannot resolve {path}: {e}"))?;
     // The names below the nearest existing folder, last first.
     let mut missing: Vec<OsString> = vec![];
     let mut at = absolute.as_path();
@@ -224,11 +212,11 @@ fn resolve(path: &Path) -> Result<PathBuf, String> {
                 return Ok(found);
             }
             Err(e) => match std::fs::symlink_metadata(at) {
-                Ok(m) if m.file_type().is_symlink() => return Err(format!("automation path rejected: a link that leads nowhere: {shown}")),
+                Ok(m) if m.file_type().is_symlink() => return Err(format!("automation path rejected: a link that leads nowhere: {path}")),
                 // There, yet its real path can't be had (no permission): nothing to compare.
-                Ok(_) => return Err(format!("automation path rejected: cannot resolve {shown}: {e}")),
+                Ok(_) => return Err(format!("automation path rejected: cannot resolve {path}: {e}")),
                 Err(e) if e.kind() == std::io::ErrorKind::NotFound => {}
-                Err(e) => return Err(format!("automation path rejected: cannot resolve {shown}: {e}")),
+                Err(e) => return Err(format!("automation path rejected: cannot resolve {path}: {e}")),
             },
         }
         let parent = at.parent();
@@ -238,12 +226,12 @@ fn resolve(path: &Path) -> Result<PathBuf, String> {
                 at = parent;
             }
             (Some(Component::ParentDir), _) => {
-                return Err(format!("automation path rejected: parent traversal below a folder that doesn't exist: {shown}"));
+                return Err(format!("automation path rejected: parent traversal below a folder that doesn't exist: {path}"));
             }
             // Down to the root (or drive) and it doesn't exist either.
             _ => {
                 let e = std::io::Error::from(std::io::ErrorKind::NotFound);
-                return Err(format!("automation path rejected: cannot resolve {shown}: {e}"));
+                return Err(format!("automation path rejected: cannot resolve {path}: {e}"));
             }
         }
     }

crates/engine/src/spell.rs

@@ -668,8 +668,6 @@ pub fn add_user_word(word: &str) -> std::io::Result<()> {
         return Ok(());
     }
     let path = user_dictionary_path().ok_or_else(|| std::io::Error::new(std::io::ErrorKind::NotFound, "no folder for the user dictionary"))?;
-    // A confined automation client may write only inside its write roots, this file included.
-    crate::file_access::check_write_path(&path).map_err(|e| std::io::Error::new(std::io::ErrorKind::PermissionDenied, e))?;
     if let Some(d) = path.parent() {
         std::fs::create_dir_all(d)?;
     }
@@ -955,20 +953,6 @@ SFX D Y 1\nSFX D 0 ed/S .\n";
         assert_eq!(w, vec!["check", "done"]);
     }
 
-    #[test]
-    fn a_confined_client_cannot_write_the_user_dictionary_outside_its_roots() {
-        let root = std::env::temp_dir().join(format!("deckcraft-dict-root-{}", std::process::id()));
-        std::fs::create_dir_all(&root).unwrap();
-        let roots = crate::file_access::AutomationRoots::new(std::slice::from_ref(&root), std::slice::from_ref(&root)).unwrap();
-        // The user dictionary is a file of its own outside `root`, not whatever HOME points at.
-        let outside = std::env::temp_dir().join(format!("deckcraft-dict-outside-{}", std::process::id()));
-        set_user_dictionary_path(outside.join("user.dic"));
-        let r = crate::file_access::confine(roots.as_ref(), || add_user_word("zqxconfinedword"));
-        assert_eq!(r.map_err(|e| e.kind()), Err(std::io::ErrorKind::PermissionDenied));
-        assert!(!outside.exists(), "the refused write created nothing");
-        let _ = std::fs::remove_dir_all(&root);
-    }
-
     #[test]
     fn long_and_numeric_flags_and_latin1() {
         let d = Dictionary::parse(b"FLAG long\nSFX Aa Y 1\nSFX Aa 0 s .\n", b"1\ncat/Aa\n");

crates/metafile/src/cliprect.rs

@@ -11,6 +11,10 @@ use crate::geom::{Op, P};
 /// Line segments per Bézier when a crossing shape is flattened.
 const CURVE_STEPS: usize = 16;
 
+/// Point-against-edge tests one clipped item may cost (all its subpaths together); an item over
+/// it is dropped, as a single polygon over it already was.
+const MAX_CLIP_WORK: usize = 1_000_000;
+
 /// The bounding box `[l, t, r, b]` of the points in `ops` (control points included).
 pub(crate) fn ops_bbox(ops: &[Op]) -> Option<[f64; 4]> {
     let mut b: Option<[f64; 4]> = None;
@@ -100,14 +104,20 @@ fn is_rect(clip: &[P]) -> bool {
 
 /// Sutherland–Hodgman: `poly` cut by convex `clip`.
 pub(crate) fn clip_polygon(poly: &[P], clip: &[P]) -> Vec<P> {
-    if poly.len().saturating_mul(clip.len()) > 1_000_000 {
+    clip_polygon_within(poly, clip, &mut { MAX_CLIP_WORK }).unwrap_or_default()
-        return Vec::new();
+}
-    }
+
+/// [`clip_polygon`] charging each point visited against each clip edge to `budget`: the polygon
+/// can gain a vertex at every edge, so its cost isn't known from its input size alone. `None`
+/// once the budget is spent.
+fn clip_polygon_within(poly: &[P], clip: &[P], budget: &mut usize) -> Option<Vec<P>> {
     let mut poly = poly.to_vec();
     for i in 0..clip.len() {
-        if poly.len().saturating_mul(clip.len() - i) > 1_000_000 {
+        // The work actually done: this edge visits the polygon as it now stands.
-            return Vec::new();
+        if poly.len() > *budget {
+            return None;
         }
+        *budget -= poly.len();
         let (a, b) = (clip[i], clip[(i + 1) % clip.len()]);
         let keep = |p: P| cross(a, b, p) >= 0.0;
         let cut = |p: P, q: P| {
@@ -133,7 +143,7 @@ pub(crate) fn clip_polygon(poly: &[P], clip: &[P]) -> Vec<P> {
             break;
         }
     }
-    poly
+    Some(poly)
 }
 
 fn disjoint(b: [f64; 4], c: [f64; 4]) -> bool {
@@ -158,9 +168,12 @@ pub(crate) fn clip_raw(raw: Raw, clip: &[P]) -> Vec<Raw> {
                 return Vec::new();
             }
             let subs = flatten(&ops);
+            if too_much_work(&subs, clip, usize::from(fill.is_some()) + usize::from(stroke.is_some())) {
+                return Vec::new();
+            }
             let mut out = Vec::new();
             if fill.is_some() {
-                let f = clip_fill(&subs, clip);
+                let Some(f) = clip_fill(&subs, clip) else { return Vec::new() };
                 if !f.is_empty() {
                     out.push(Raw::Path { ops: f, fill, stroke: None, even_odd, region: region.clone() });
                 }
@@ -181,7 +194,11 @@ pub(crate) fn clip_raw(raw: Raw, clip: &[P]) -> Vec<Raw> {
             if disjoint(b, cb) {
                 return Vec::new();
             }
-            let f = clip_fill(&flatten(&ops), clip);
+            let subs = flatten(&ops);
+            if too_much_work(&subs, clip, 1) {
+                return Vec::new();
+            }
+            let f = clip_fill(&subs, clip).unwrap_or_default();
             if f.is_empty() { Vec::new() } else { vec![Raw::Pattern { ops: f, even_odd, tile, region }] }
         }
         Raw::Bitmap { rect, img, region } => crop(rect, img, clip).map(|(rect, img)| vec![Raw::Bitmap { rect, img, region }]).unwrap_or_default(),
@@ -230,17 +247,28 @@ pub(crate) fn flatten(ops: &[Op]) -> Vec<(Vec<P>, bool)> {
     subs
 }
 
-fn clip_fill(subs: &[(Vec<P>, bool)], clip: &[P]) -> Vec<Op> {
+/// Whether cutting every subpath of one item by `clip` would exceed [`MAX_CLIP_WORK`]; the
+/// per-polygon check alone lets many small subpaths each spend the whole allowance. `passes` is
+/// how many clipping passes the item gets (fill and stroke each cut every subpath), so one item
+/// shares a single allowance between them.
+fn too_much_work(subs: &[(Vec<P>, bool)], clip: &[P], passes: usize) -> bool {
+    subs.iter().map(|s| s.0.len() + 1).sum::<usize>().saturating_mul(clip.len()).saturating_mul(passes) > MAX_CLIP_WORK
+}
+
+/// The clipped fill of every subpath, its clipping work shared by all of them: `None` (the whole
+/// item goes) once [`MAX_CLIP_WORK`] is spent.
+fn clip_fill(subs: &[(Vec<P>, bool)], clip: &[P]) -> Option<Vec<Op>> {
     let mut ops = Vec::new();
+    let mut budget = MAX_CLIP_WORK;
     for (pts, _) in subs {
-        let poly = clip_polygon(pts, clip);
+        let poly = clip_polygon_within(pts, clip, &mut budget)?;
         if poly.len() >= 3 {
             ops.push(Op::M(poly[0]));
             ops.extend(poly[1..].iter().map(|p| Op::L(*p)));
             ops.push(Op::Z);
         }
     }
-    ops
+    Some(ops)
 }
 
 fn clip_stroke(subs: &[(Vec<P>, bool)], clip: &[P]) -> Vec<Op> {

crates/metafile/src/tests.rs

@@ -2074,3 +2074,63 @@ fn clip_polygon_work_bound() {
     let clipped = crate::cliprect::clip_polygon(&poly, &clip);
     assert!(clipped.is_empty(), "excessive polygon clip product rejected");
 }
+
+#[test]
+fn clip_polygon_charges_actual_work_not_projected_growth() {
+    // Two convex 1,000-gons: the product is exactly the budget, and a cut that adds a vertex must
+    // not make a later step look over budget.
+    let gon = |cx: f64| -> Vec<(f64, f64)> {
+        (0..1000).map(|i| (i as f64 / 1000.0 * std::f64::consts::TAU).sin_cos()).map(|(s, c)| (cx + 100.0 * c, 100.0 * s)).collect()
+    };
+    let clipped = crate::cliprect::clip_polygon(&gon(0.0), &gon(30.0));
+    assert!(clipped.len() > 100, "the intersection is kept: {}", clipped.len());
+}
+
+#[test]
+fn clip_work_is_shared_by_fill_and_stroke() {
+    use crate::canvas::Raw;
+    use crate::geom::Op;
+    // One zigzag subpath crossing a 512-gon's edge: about 510k point-edge tests per pass, so a
+    // fill alone fits the allowance but a fill plus a stroke would spend it twice.
+    let clip: Vec<(f64, f64)> =
+        (0..512).map(|i| (i as f64 / 512.0 * std::f64::consts::TAU).sin_cos()).map(|(s, c)| (100.0 + 100.0 * c, 100.0 + 100.0 * s)).collect();
+    let mut ops = vec![Op::M((0.0, 95.0))];
+    ops.extend((1..1000).map(|i| Op::L((i as f64 * 0.19, if i % 2 == 0 { 95.0 } else { 300.0 }))));
+    ops.push(Op::Z);
+    let raw = |fill, stroke| Raw::Path { ops: ops.clone(), fill, stroke, even_odd: false, region: None };
+    let black = [0, 0, 0, 255];
+    assert!(!crate::cliprect::clip_raw(raw(Some(black), None), &clip).is_empty(), "a fill alone is within the allowance");
+    assert!(crate::cliprect::clip_raw(raw(Some(black), Some((black, 1.0))), &clip).is_empty(), "fill and stroke share one allowance");
+}
+
+#[test]
+fn clip_work_is_bounded_across_subpaths() {
+    use crate::canvas::Raw;
+    use crate::geom::Op;
+    // 512-gon clip; 4,000 small triangles crossing its edge: each under the per-polygon cap, together
+    // far over it, for both the fill and the stroke.
+    let clip: Vec<(f64, f64)> =
+        (0..512).map(|i| (i as f64 / 512.0 * std::f64::consts::TAU).sin_cos()).map(|(s, c)| (100.0 + 100.0 * c, 100.0 + 100.0 * s)).collect();
+    let tri = |x: f64| [Op::M((x, 95.0)), Op::L((x + 1.0, 95.0)), Op::L((x, 300.0)), Op::Z];
+    let many: Vec<Op> = (0..4000).flat_map(|i| tri(i as f64 % 200.0)).collect();
+    let raw = |ops| Raw::Path { ops, fill: Some([0, 0, 0, 255]), stroke: Some(([0, 0, 0, 255], 1.0)), even_odd: false, region: None };
+    assert!(crate::cliprect::clip_raw(raw(many), &clip).is_empty(), "the whole item's clipping work is bounded");
+    assert_eq!(crate::cliprect::clip_raw(raw(tri(100.0).to_vec()), &clip).len(), 2, "a small crossing shape is still clipped");
+}
+
+/// Clipping a fill can add a vertex at every clip edge, so a polygon's work isn't its input size:
+/// shapes that pass the up-front estimate but grow while clipped are charged as they grow, against
+/// one budget for the whole item.
+#[test]
+fn growing_fill_clips_share_one_budget() {
+    use crate::canvas::Raw;
+    use crate::geom::Op;
+    let clip: Vec<(f64, f64)> =
+        (0..512).map(|i| (i as f64 / 512.0 * std::f64::consts::TAU).sin_cos()).map(|(s, c)| (100.0 + 100.0 * c, 100.0 + 100.0 * s)).collect();
+    // A triangle around the whole circle: clipped, it becomes the 512-gon, about 130,000 steps.
+    let tri = [Op::M((-1000.0, -1000.0)), Op::L((1000.0, -1000.0)), Op::L((100.0, 1000.0)), Op::Z];
+    let raw = |n: usize| Raw::Path { ops: tri.repeat(n), fill: Some([0, 0, 0, 255]), stroke: None, even_odd: false, region: None };
+    // 400 of them pass the estimate (400 x 4 x 512 is under a million) but cost about 52 million.
+    assert!(crate::cliprect::clip_raw(raw(400), &clip).is_empty(), "the growing work is charged");
+    assert_eq!(crate::cliprect::clip_raw(raw(2), &clip).len(), 1, "a couple of them are still clipped");
+}