externals.rs module (#812)
* Document and update the API of the `externals.rs` module This commit ensures that all public methods and items are documented in the `externals.rs` module, notably all external values that can be imported and exported in WebAssembly. Along the way this also tidies up the API and fixes a few bugs: * `Global::new` now returns a `Result` and fails if the provided value does not match the type of the global. * `Global::set` now returns a `Result` and fails if the global is either immutable or the provided value doesn't match the type of the global. * `Table::new` now fails if the provided initializer does not match the element type. * `Table::get` now returns `Option<Val>` instead of implicitly returning null. * `Table::set` now returns `Result<()>`, returning an error on out of bounds or if the input type is of the wrong type. * `Table::grow` now returns `Result<u32>`, returning the previous number of table elements if succesful or an error if the maximum is reached or the initializer value is of the wrong type. Additionally a bug was fixed here where if the wrong initializer was provided the table would be grown still, but initialization would fail. * `Memory::data` was renamed to `Memory::data_unchecked_mut`. Additionally `Memory::data_unchecked` was added. Lots of caveats were written down about how using the method can go wrong. * `Memory::grow` now returns `Result<u32>`, returning an error if growth fails or the number of pages previous the growth if successful. * Run rustfmt * Fix another test * Update crates/api/src/externals.rs Co-Authored-By: Sergei Pepyakin <s.pepyakin@gmail.com> Co-authored-by: Sergei Pepyakin <s.pepyakin@gmail.com>
Wasmtime: a WebAssembly Runtime
A Bytecode Alliance project
Wasmtime is a standalone wasm-only optimizing runtime for WebAssembly and WASI. It runs WebAssembly code outside of the Web, and can be used both as a command-line utility or as a library embedded in a larger application.
To get started, visit wasmtime.dev.
There are Rust, C, and C++ toolchains that can compile programs with WASI. See the WASI intro for more information, and the WASI tutorial for a tutorial on compiling and running programs using WASI and wasmtime, as well as an overview of the filesystem sandboxing system.
Wasmtime passes the WebAssembly spec testsuite. To run it, update the
tests/spec_testsuite submodule with git submodule update --remote, and it
will be run as part of cargo test.
Wasmtime does not yet implement Spectre mitigations, however this is a subject of ongoing research.
Additional goals for Wasmtime include:
- Support a variety of host APIs (not just WASI), with fast calling sequences, and develop proposals for additional API modules to be part of WASI.
- Facilitate development and testing around the Cranelift and Lightbeam JITs, and other WebAssembly execution strategies.
- Develop a native ABI used for compiling WebAssembly suitable for use in both JIT and AOT to native object files.
Including Wasmtime in your project
Wasmtime exposes an API for embedding as a library through the wasmtime subcrate,
which contains both a high-level and safe Rust API, as well as a C-compatible API
compatible with the proposed WebAssembly C API.
For more information, see the Rust API embedding chapter of the Wasmtime documentation.
It's Wasmtime.