1112769 - Move js/src/vm/NumericConversions.h to js/public/NumericConversions.h as public API

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jeff Walden [:Waldo]]

ToInt32, ToInteger, and so on are all widely used in ES3/5/6, and in WebIDL, and possibly in other web specs.  They deserve to be exposed as public API in namespace JS.

Comment 1

[Jeff Walden [:Waldo]]

Attachment: Patch

It's mildly obnoxious that we have other functions named ToInt32 and so on, in a very few places, that take a Value and return a number via outparam, in namespace js.  The result is that inside namespace js, in the rare case where you're using one of these functions *not* by directly calling it, you'll need to explicitly request the namespace JS version if you want it.  This bit the few JS_FUNC_TO_DATA_PTR(void *, js::ToInt32) cases, that I had to convert to BitwiseCast<void*, int32_t(*)(double)>(JS::ToInt32), with the From type explicitly specified.  Not the end of the world.

Comment 2

[Jason Orendorff [:jorendorff]]

Comment on attachment 8538078 [details] [diff] [review]
Patch

Review of attachment 8538078 [details] [diff] [review]:
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To me, these two operations (converting a double to various integer types, which is concerned with numerical correctness; and coercing a Value to various integer types, which can execute arbitrary JS and possibly throw) are different enough that they should have different names. Would prefer JS::DoubleToInt32 and so on.

Alternatively, rename to js/public/Conversions.h with the understanding that each function will eventually get a fallible Value-oriented overload.

Comment 3

[Jeff Walden [:Waldo]]

I renamed to js/public/Conversions.h.  The functions' semantics are exactly those of the corresponding named algorithm in ES5/ES6, which seems to be no difference to me, except in invocation and error-checking and other window dressing.

https://hg.mozilla.org/integration/mozilla-inbound/rev/71083c9726d5
https://hg.mozilla.org/integration/mozilla-inbound/rev/46167c93631a

I have a patch moving most of the rest of the other spec conversion methods into this header, that I'll throw into the other bug now.

Comment 4

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/71083c9726d5
https://hg.mozilla.org/mozilla-central/rev/46167c93631a