Files
vectorcraft/crates/doc/src/clipnest.rs
T
Dylan M. TaylorandClaude Opus 5.5 b12ee928f3 Security: document model generation budgets for live art, clipping runs, placed documents, graph masks, path reading and native entries
CodeRabbit findings #58, #75, #82, #113, #159, #175, #187:

- Live evaluation (expansion, envelope mapping and everything inside) makes at most 4M
  objects (`MAX_GENERATED`); deep expansion counts what each live object makes, and envelope
  image pieces count before they are cut.
- Clipping runs copy at most 8M clip path elements together; past it runs are plain groups.
- Exports read at most 256 placed documents; the rest show their previews.
- Graph design and marker budgets count opacity-mask art (`Node::count_with_masks`).
- Native files read at most 32M anchors (4M on wasm) of paths; the web build allows 1 GiB of
  entries after the JSON.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-24 17:19:16 +07:00

99 lines
4.1 KiB
Rust

//! Clipped and grouped art read from page descriptions (metafiles, PostScript) into clipping
//! groups and groups.
//!
//! Importers record each object they draw with the chain of clips (and groups) in force at the
//! time, outermost first ([`Drawn`]); [`nest`] then puts runs of objects under the same clip into
//! one clipping group (under the same group into one group), nesting groups for nested clips,
//! keeping the drawing order.
use std::sync::Arc;
use vectorcraft_geom::{BezPath, FillRule, PathData};
use crate::appearance::Appearance;
use crate::{Document, Node, NodeKind};
/// A clip: a region in document space and its rule, or a plain group (one that holds its art
/// without clipping it, such as an Illustrator file's `u` … `U`). Each has an id unique within an
/// import, so what one clip clips (or one group holds) can be grouped.
#[derive(Debug)]
pub struct Clip {
pub id: u32,
/// The region and its rule; `None` for a plain group.
pub region: Option<(BezPath, FillRule)>,
}
/// Deepest nesting of clips, and of groups, an importer records ([`nest`] goes one level deeper
/// for each): deeper ones are left out. As deep as a document's objects may nest
/// ([`crate::MAX_DEPTH`]) under a layer, around the art; clips in groups that deep together are
/// merged by [`Document::limit_depth`].
pub const MAX_NEST: usize = crate::MAX_DEPTH - 2;
/// The warning for clips left out for nesting deeper than [`MAX_NEST`].
pub fn deep_clips() -> String {
format!("clips nested more than {MAX_NEST} deep were left out: what they clip is clipped by the clips around them")
}
/// Objects in drawing order, each with its clips (outermost first).
pub type Drawn = Vec<(Vec<Arc<Clip>>, Node)>;
/// The nodes of `items`, those under clips grouped into clipping groups and those in groups into
/// groups (ids from `doc`), in order.
pub fn nest(doc: &mut Document, items: Drawn) -> Vec<Arc<Node>> {
let mut left = MAX_CLIP_ELEMENTS;
nest_at(doc, items, 0, &mut left)
}
/// Most path elements the clipping paths [`nest`] makes may have together. Each run of objects
/// under a clip gets its own copy of the clip's path, so one large clip used again around many
/// short runs (an EMF restoring one saved clip between drawings) multiplied it. Past it, runs are
/// grouped without their clip.
pub const MAX_CLIP_ELEMENTS: usize = 8_000_000;
/// [`nest`] for the clips at `depth` and deeper, with `left` of [`MAX_CLIP_ELEMENTS`].
fn nest_at(doc: &mut Document, items: Drawn, depth: usize, left: &mut usize) -> Vec<Arc<Node>> {
let mut out: Vec<Arc<Node>> = vec![];
let mut group: Drawn = vec![];
let mut clip: Option<Arc<Clip>> = None;
for (chain, node) in items {
let here = chain.get(depth).cloned();
if here.as_ref().map(|c| c.id) != clip.as_ref().map(|c| c.id) {
if let Some(c) = clip.take() {
out.push(clip_group(doc, &c, std::mem::take(&mut group), depth, left));
}
clip = here.clone();
}
match here {
Some(_) => group.push((chain, node)),
None => out.push(Arc::new(node)),
}
}
if let Some(c) = clip {
out.push(clip_group(doc, &c, group, depth, left));
}
out
}
/// A clipping group of `items`, clipped by `c` (their clip at `depth`), or their group when `c` is
/// a plain group.
fn clip_group(doc: &mut Document, c: &Clip, items: Drawn, depth: usize, left: &mut usize) -> Arc<Node> {
let mut children = vec![];
let region = c.region.as_ref().filter(|(bp, _)| match left.checked_sub(bp.elements().len()) {
Some(rest) => {
*left = rest;
true
}
None => false,
});
if let Some((bp, r)) = region {
let mut path = Node::path(doc.alloc_id(), PathData::from_bezpath(bp), Appearance::default());
if let NodeKind::Path { clipping, rule, .. } = &mut path.kind {
*clipping = true;
*rule = *r;
}
children.push(Arc::new(path));
}
children.extend(nest_at(doc, items, depth + 1, left));
Arc::new(Node::new(doc.alloc_id(), NodeKind::Group { children, clip: region.is_some() }))
}