Files
wasmtime/crates/c-api/src/lib.rs
Alex Crichton 7a1b7cdf92 Implement RFC 11: Redesigning Wasmtime's APIs (#2897)
Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.
2021-06-03 09:10:53 -05:00

110 lines
2.8 KiB
Rust

//! This crate is the implementation of Wasmtime's C API.
//!
//! This crate is not intended to be used from Rust itself, for that see the
//! `wasmtime` crate. Otherwise this is typically compiled as a
//! cdylib/staticlib. Documentation for this crate largely lives in the header
//! files of the `include` directory for this crate.
//!
//! At a high level this crate implements the `wasm.h` API with some gymnastics,
//! but otherwise an accompanying `wasmtime.h` API is provided which is more
//! specific to Wasmtime and has fewer gymnastics to implement.
#![allow(non_snake_case, non_camel_case_types, non_upper_case_globals)]
mod config;
mod engine;
mod error;
mod r#extern;
mod func;
mod global;
mod instance;
mod linker;
mod memory;
mod module;
mod r#ref;
mod store;
mod table;
mod trap;
mod types;
mod val;
mod vec;
pub use crate::config::*;
pub use crate::engine::*;
pub use crate::error::*;
pub use crate::func::*;
pub use crate::global::*;
pub use crate::instance::*;
pub use crate::linker::*;
pub use crate::memory::*;
pub use crate::module::*;
pub use crate::r#extern::*;
pub use crate::r#ref::*;
pub use crate::store::*;
pub use crate::table::*;
pub use crate::trap::*;
pub use crate::types::*;
pub use crate::val::*;
pub use crate::vec::*;
#[cfg(feature = "wasi")]
mod wasi;
#[cfg(feature = "wasi")]
pub use crate::wasi::*;
#[cfg(feature = "wat")]
mod wat2wasm;
#[cfg(feature = "wat")]
pub use crate::wat2wasm::*;
/// Initialize a `MaybeUninit<T>`
///
/// TODO: Replace calls to this function with
/// https://doc.rust-lang.org/nightly/std/mem/union.MaybeUninit.html#method.write
/// once it is stable.
pub(crate) fn initialize<T>(dst: &mut std::mem::MaybeUninit<T>, val: T) {
unsafe {
std::ptr::write(dst.as_mut_ptr(), val);
}
}
/// Helper for running a C-defined finalizer over some data when the Rust
/// structure is dropped.
pub struct ForeignData {
data: *mut std::ffi::c_void,
finalizer: Option<extern "C" fn(*mut std::ffi::c_void)>,
}
unsafe impl Send for ForeignData {}
unsafe impl Sync for ForeignData {}
impl Drop for ForeignData {
fn drop(&mut self) {
if let Some(f) = self.finalizer {
f(self.data);
}
}
}
/// Helper for creating Rust slices from C inputs.
///
/// This specifically disregards the `ptr` argument if the length is zero. The
/// `ptr` in that case maybe `NULL` or invalid, and it's not valid to have a
/// zero-length Rust slice with a `NULL` pointer.
unsafe fn slice_from_raw_parts<'a, T>(ptr: *const T, len: usize) -> &'a [T] {
if len == 0 {
&[]
} else {
std::slice::from_raw_parts(ptr, len)
}
}
/// Same as above, but for `*_mut`
unsafe fn slice_from_raw_parts_mut<'a, T>(ptr: *mut T, len: usize) -> &'a mut [T] {
if len == 0 {
&mut []
} else {
std::slice::from_raw_parts_mut(ptr, len)
}
}