7c67378ab6
* wiggle: copy guest strings from shared memory Along the same lines as #5471, this change adds a new smart pointer, `GuestStrCow`, to copy the string bytes over from Wasm memory to the host when the string is found in shared memory. This is necessary to maintain Rust guarantees: with shared memory, the bytes backing a `GuestStr` could be altered by another thread and this would invalidate the assumption that we can dereference at any point to `&str`. `GuestStrCow` is essentially a wrapper around `GuestStr` when the memory is not shared but copies the memory region into a `String` when the memory is shared. This change updates the uses of Wiggle strings in both wasi-common and wasi-crypto. * review: perform UTF-8 check on `GuestStr` construction
wiggle
Wiggle is a code generator for the host side of a witx interface. It is
invoked as a Rust procedural macro.
Wiggle is not specialized to any particular WebAssembly runtime. It is usable in at least Wasmtime and Lucet.
Learning more
Read the docs on docs.rs.
There are child crates for integrating with Wasmtime and Lucet.
The wasi-common crate is implemented using Wiggle and the wasmtime-wasi crate integrates wasi-common with the Wasmtime engine.
Andrew Brown wrote a great blog post on using Wiggle with Wasmtime.