[BridgeJS] Pass String parameters unretained by default
Nobody has claimed this yet.
Assessment
- Difficulty
- 5/5
- Estimated time
- Over a week
- Newbie friendliness
- 28/100
- Issue type
- Refactor
- Clarity
- Mostly clear
- Activity status
- Stale
- Tech stack
- javascript, swift, wasm
- Domain
- api, performance, web-dev
Research direction
Start by tracing _swift_js_make_js_string, bridgeJSLowerParameter, and the generated bjs_hello thunk shown in the issue, then inspect how JSString references are represented. Done means ordinary String parameters cross the bridge without a JS memory-store retain/release cycle while JSString still supports caller-controlled by-reference reuse; verify the impact against the ElementaryUI performance benchmarks.
Written by the indexing model from the issue text.
Description
When calling a JS function through BridgeJS with String parameters, every String is
- lowered by calling
_swift_js_make_js_string - which decodes and retains in JS object store (new entry, new ref = 1)
- the object store ref is passed as wasm parameter
- the JS thunk immediately get the object and releases (count--, remove from store)
this is very wasteful, and makes retain the number one bottleneck in current ElementaryUI performance benchmarks.
Example:
@JSFunction func hello(_ v: String) throws
// generates
func _$hello(_ v: String) throws(JSException) -> Void {
let vValue = v.bridgeJSLowerParameter()
bjs_hello(vValue)
if let error = _swift_js_take_exception() {
throw error
}
}
function bjs_hello(v) {
try {
const vObject = swift.memory.getObject(v);
swift.memory.release(v);
imports.hello(vObject);
} catch (error) {
setException(error);
}
}
I suggest:
- passing
Stringalways "in-line" (ie: as address + length) without retaining in the JSmemorystore - still support
JSStringby-ref to control Swift caller caching (ie: retain once and use same ref multiple times)
- Dominant language
- Swift
- Stars
- 986
- Forks
- 76
- Avg merge
- 21h 11m
- Merged PRs (30d)
- 4
Contributor guide
First steps
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