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denoland-deno/core/examples/disable_ops.rs
Matt Mastracci a1764f7690
refactor(core): Improve ergonomics of managing ASCII strings (#18498)
This is a follow-on to the earlier work in reducing string copies,
mainly focused on ensuring that ASCII strings are easy to provide to the
JS runtime.

While we are replacing a 16-byte reference in a number of places with a
24-byte structure (measured via `std::mem::size_of`), the reduction in
copies wins out over the additional size of the arguments passed into
functions.

Benchmarking shows approximately the same if not slightly less wallclock
time/instructions retired, but I believe this continues to open up
further refactoring opportunities.
2023-04-04 06:46:31 -06:00

27 lines
710 B
Rust

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
//! This example shows you how to define ops in Rust and then call them from
//! JavaScript.
use deno_core::Extension;
use deno_core::JsRuntime;
use deno_core::RuntimeOptions;
fn main() {
let my_ext = Extension::builder("my_ext")
.middleware(|op| match op.name {
"op_print" => op.disable(),
_ => op,
})
.build();
// Initialize a runtime instance
let mut runtime = JsRuntime::new(RuntimeOptions {
extensions: vec![my_ext],
..Default::default()
});
// Deno.core.print() will now be a NOP
runtime
.execute_script_static("<usage>", r#"Deno.core.print("I'm broken")"#)
.unwrap();
}