This commit changes the build process in a way that preserves already
registered ops in the snapshot. This allows us to skip creating hundreds of
"v8::String" on each startup, but sadly there is still some op registration
going on startup (however we're registering 49 ops instead of >200 ops).
This situation could be further improved, by moving some of the ops
from "runtime/" to a separate extension crates.
---------
Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>
Uses SeqOneByteString optimization to do zero-copy `&str` arguments in
fast calls.
- [x] Depends on https://github.com/denoland/rusty_v8/pull/1129
- [x] Depends on
https://chromium-review.googlesource.com/c/v8/v8/+/4036884
- [x] Disable in async ops
- [x] Make it work with owned `String` with an extra alloc in fast path.
- [x] Support `Cow<'_, str>`. Owned for slow case, Borrowed for fast
case
```rust
#[op]
fn op_string_len(s: &str) -> u32 {
str.len() as u32
}
```
