mirror of
https://github.com/denoland/deno.git
synced 2024-11-01 09:24:20 -04:00
ca66978a5a
This PR introduces Wasm ops. These calls are optimized for entry from
Wasm land.
The `#[op(wasm)]` attribute is opt-in.
Last parameter `Option<&mut [u8]>` is the memory slice of the Wasm
module *when entered from a Fast API call*. Otherwise, the user is
expected to implement logic to obtain the memory if `None`
```rust
#[op(wasm)]
pub fn op_args_get(
offset: i32,
buffer_offset: i32,
memory: Option<&mut [u8]>,
) {
// ...
}
```
67 lines
1.9 KiB
Rust
67 lines
1.9 KiB
Rust
// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
|
|
|
|
use deno_core::op;
|
|
use deno_core::Extension;
|
|
use deno_core::JsRuntime;
|
|
use deno_core::RuntimeOptions;
|
|
use std::mem::transmute;
|
|
use std::ptr::NonNull;
|
|
|
|
// This is a hack to make the `#[op]` macro work with
|
|
// deno_core examples.
|
|
// You can remove this:
|
|
|
|
use deno_core::*;
|
|
|
|
struct WasmMemory(NonNull<v8::WasmMemoryObject>);
|
|
|
|
fn wasm_memory_unchecked(state: &mut OpState) -> &mut [u8] {
|
|
let WasmMemory(global) = state.borrow::<WasmMemory>();
|
|
// SAFETY: `v8::Local` is always non-null pointer; the `HandleScope` is
|
|
// already on the stack, but we don't have access to it.
|
|
let memory_object = unsafe {
|
|
transmute::<NonNull<v8::WasmMemoryObject>, v8::Local<v8::WasmMemoryObject>>(
|
|
*global,
|
|
)
|
|
};
|
|
let backing_store = memory_object.buffer().get_backing_store();
|
|
let ptr = backing_store.data().unwrap().as_ptr() as *mut u8;
|
|
let len = backing_store.byte_length();
|
|
// SAFETY: `ptr` is a valid pointer to `len` bytes.
|
|
unsafe { std::slice::from_raw_parts_mut(ptr, len) }
|
|
}
|
|
|
|
#[op(wasm)]
|
|
fn op_wasm(state: &mut OpState, memory: Option<&mut [u8]>) {
|
|
let memory = memory.unwrap_or_else(|| wasm_memory_unchecked(state));
|
|
memory[0] = 69;
|
|
}
|
|
|
|
#[op(v8)]
|
|
fn op_set_wasm_mem(
|
|
scope: &mut v8::HandleScope,
|
|
state: &mut OpState,
|
|
memory: serde_v8::Value,
|
|
) {
|
|
let memory =
|
|
v8::Local::<v8::WasmMemoryObject>::try_from(memory.v8_value).unwrap();
|
|
let global = v8::Global::new(scope, memory);
|
|
state.put(WasmMemory(global.into_raw()));
|
|
}
|
|
|
|
fn main() {
|
|
// Build a deno_core::Extension providing custom ops
|
|
let ext = Extension::builder()
|
|
.ops(vec![op_wasm::decl(), op_set_wasm_mem::decl()])
|
|
.build();
|
|
|
|
// Initialize a runtime instance
|
|
let mut runtime = JsRuntime::new(RuntimeOptions {
|
|
extensions: vec![ext],
|
|
..Default::default()
|
|
});
|
|
|
|
runtime
|
|
.execute_script("<usage>", include_str!("wasm.js"))
|
|
.unwrap();
|
|
}
|