Replace unsafe std::mem::transmute calls in Rust WASM path code with
validated TryFrom conversions to prevent undefined behavior from invalid
enum discriminant values. This was the most likely root cause of the
"No matching clause: -19772" production crash -- corrupted bytes flowing
through transmute could produce arbitrary invalid enum variants.
Fix byteOffset handling throughout the CLJS PathData serialization
pipeline. DataView instances created via buf/slice carry a non-zero
byteOffset, but from-bytes, transit write handler, -write-to,
buf/clone, and buf/equals? all operated on the full underlying
ArrayBuffer, ignoring offset and length. This could silently produce
PathData with incorrect size or content.
Rust changes (render-wasm):
- RawSegmentData: From<[u8; N]> -> TryFrom<[u8; N]> with discriminant
validation (must be 0x01-0x04) before transmuting
- RawBoolType: From<u8> -> TryFrom<u8> with explicit match on 0-3
- Add #[wasm_error] to set_shape_path_content, current_to_path,
convert_stroke_to_path, and set_shape_bool_type so panics are caught
and routed through the WASM error protocol instead of crashing
- set_shape_path_content: replace .expect() with proper Result/? error
propagation per segment
- Remove unused From<BytesType> bound from SerializableResult trait
CLJS changes (common):
- from-bytes: use DataView.byteLength instead of ArrayBuffer.byteLength
for DataView inputs; preserve byteOffset/byteLength when converting
from Uint8Array, Uint32Array, and Int8Array
- Transit write handler: construct Uint8Array with byteOffset and
byteLength from the DataView, not the full backing ArrayBuffer
- -write-to: same byteOffset/byteLength fix
- buf/clone: copy only the DataView byte range using Uint8Array with
proper offset, not Uint32Array over the full ArrayBuffer
- buf/equals?: compare DataView byte ranges using Uint8Array with
proper offset, not the full backing ArrayBuffers
Frontend changes:
- shape-to-path, stroke-to-path, calculate-bool*: wrap WASM call and
buffer read in try/catch to ensure mem/free is always called, even
when an exception occurs between the WASM call and the free call
Signed-off-by: Andrey Antukh <niwi@niwi.nz>
