60 lines
2.3 KiB
Rust
60 lines
2.3 KiB
Rust
//! Sandboxed WebAssembly plug-ins for VectorCraft.
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//!
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//! A plug-in is a WebAssembly module that implements the VectorCraft plug-in ABI (v1, documented
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//! in `docs/plugins.md`). It runs in [`wasmi`], a pure-Rust interpreter, with:
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//!
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//! - **no host imports**: no WASI, file system, network, clock or randomness. A module that
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//! imports anything is rejected;
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//! - an **instruction budget** (fuel) per call, metered in slices so a wall-clock deadline is
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//! also enforced (native builds), so infinite loops end with an error;
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//! - a **linear-memory cap**, a **recursion-depth cap** and wasmi's strict module limits;
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//! - a **fresh instance per run**, so no state leaks between calls.
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//!
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//! Every failure (malformed module, trap, exhausted budget, bad output) is an [`Error`]; nothing
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//! a module does can panic or hang the host.
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//!
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//! Plug-ins see the document as JSON ([`objects`]): the selected paths and compound paths with
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//! their geometry, fills, strokes (gradients included) and opacity. An **object filter** returns
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//! the objects to keep, change or add, applied to the document as one edit
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//! ([`objects::apply_output`]); a **live effect** ([`effect`]) rewrites one object's geometry each
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//! time it is drawn, from an appearance stack. The process-wide [`registry`] holds the installed
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//! plug-ins.
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#![forbid(unsafe_code)]
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pub mod effect;
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pub mod manifest;
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pub mod objects;
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pub mod registry;
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mod runtime;
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pub mod wat;
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pub use manifest::{Kind, Manifest, ParamSpec};
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pub use runtime::{ABI_VERSION, Limits, Plugin};
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/// A plug-in error. Every way a module can misbehave ends here, never in a panic.
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#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
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pub enum Error {
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#[error("not a valid plug-in module: {0}")]
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Module(String),
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#[error("plug-in ABI: {0}")]
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Abi(String),
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#[error("plug-in manifest: {0}")]
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Manifest(String),
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#[error("plug-in trapped: {0}")]
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Trap(String),
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#[error("plug-in exceeded its {0}")]
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Limit(String),
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#[error("plug-in parameters: {0}")]
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Params(String),
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#[error("plug-in output: {0}")]
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Output(String),
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#[error("plug-in failed: {0}")]
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Failed(String),
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#[error("no plug-in {0:?} is installed")]
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NotFound(String),
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#[error("{0}")]
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Io(String),
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}
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pub type Result<T> = std::result::Result<T, Error>;
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