mirror of
https://github.com/denoland/deno.git
synced 2024-12-04 17:18:23 -05:00
31 lines
1.3 KiB
Rust
31 lines
1.3 KiB
Rust
// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
|
|
use std::collections::HashMap;
|
|
|
|
// KeyCache stores a pool struct keys mapped to v8,
|
|
// to minimize allocs and speed up decoding/encoding `v8::Object`s
|
|
// TODO: experiment with in from_v8/to_v8
|
|
pub struct KeyCache(HashMap<&'static str, v8::Global<v8::String>>);
|
|
|
|
// creates an optimized v8::String for a struct field
|
|
// TODO: experiment with external strings
|
|
// TODO: evaluate if own KeyCache is better than v8's dedupe
|
|
pub fn v8_struct_key<'s>(
|
|
scope: &mut v8::HandleScope<'s>,
|
|
field: &'static str,
|
|
) -> v8::Local<'s, v8::String> {
|
|
// Internalized v8 strings are significantly faster than "normal" v8 strings
|
|
// since v8 deduplicates re-used strings minimizing new allocations
|
|
// see: https://github.com/v8/v8/blob/14ac92e02cc3db38131a57e75e2392529f405f2f/include/v8.h#L3165-L3171
|
|
v8::String::new_from_utf8(
|
|
scope,
|
|
field.as_ref(),
|
|
v8::NewStringType::Internalized,
|
|
)
|
|
.unwrap()
|
|
|
|
// TODO: consider external strings later
|
|
// right now non-deduped external strings (without KeyCache)
|
|
// are slower than the deduped internalized strings by ~2.5x
|
|
// since they're a new string in v8's eyes and needs to be hashed, etc...
|
|
// v8::String::new_external_onebyte_static(scope, field).unwrap()
|
|
}
|