mirror of
https://github.com/aphrody-labs/rusty_v8.git
synced 2026-10-14 04:19:09 +00:00
Nathan Whitaker
65fb5c1683
Before this change, `HandleScope`s (and other scope types) were stored in the heap and we did bookkeeping at runtime of the current stack of scopes. The reasons were primarily:
- raw handle scopes need to be pinned in memory once initialized
- we couldn't enforce at compile that a `Local` didn't outlive the scope it was created from
The latter lead us to need a workaround where scopes actually were not exited when they were dropped, rather they were exited the next time we activated another scope.
This change refactors the scope implementation to:
- make scopes stack allocated, to reduce overhead of using them
- remove the runtime bookkeeping
- use lifetimes to prevent scopes from being dropped, so we can remove the `zombie` scope workaround
The practical effect is that creating a handle scope changes from:
```rust
let mut scope = v8::HandleScope::new(&mut isolate);
let local = v8::Integer::new(&mut scope, 123);
```
to:
```rust
let scope = std::pin::pin!(v8::HandleScope::new(&mut isolate));
let scope = scope.init();
let local = v8::Integer::new(&scope, 123);
// or shorter
v8::scope!(let scope, &mut isolate);
let local = v8::Integer::new(scope, 123);
```
If you accept a `HandleScope` as a parameter in a function, you would change it from:
```rust
fn takes_scope(s: &mut v8::HandleScope) {}
```
to
```rust
fn takes_scope(s: &mut v8::PinScope) {}
```
(`v8::PinScope` is a type alias for a pinned handle scope).
23 lines
749 B
Rust
23 lines
749 B
Rust
#[test]
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fn single_threaded_default_platform() {
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v8::V8::set_flags_from_string("--single_threaded");
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v8::V8::initialize_platform(
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v8::new_single_threaded_default_platform(false).make_shared(),
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);
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v8::V8::initialize();
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{
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let isolate = &mut v8::Isolate::new(Default::default());
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v8::scope!(let scope, isolate);
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let context = v8::Context::new(scope, Default::default());
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let scope = &mut v8::ContextScope::new(scope, context);
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let source = v8::String::new(scope, "Math.random()").unwrap();
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let script = v8::Script::compile(scope, source, None).unwrap();
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let result = script.run(scope).unwrap();
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let _ = result.to_string(scope).unwrap();
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}
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unsafe { v8::V8::dispose() };
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v8::V8::dispose_platform();
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}
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