995047 - Change stack/exception APIs to hand out AString instead of AUTF8String

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Boris Zbarsky [:bzbarsky]]

Makes them faster from JS, and removes some internal conversions that were sucking perf-wise.  Speeds up my testcase in bug 920116 by 25% or so.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Attachment: Change out stack/exception APIs to hand out AString instead of AUTF8String for filename/functionname, so we end up with fewer string conversions in practice.

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

Comment on attachment 8405126 [details] [diff] [review]
Change out stack/exception APIs to hand out AString instead of AUTF8String for filename/functionname, so we end up with fewer string conversions in practice.

>diff --git a/dom/base/DOMException.cpp b/dom/base/DOMException.cpp

> /* readonly attribute AUTF8String filename; */
Not AUTH8String anymore

> NS_IMETHODIMP
>-Exception::GetFilename(nsACString& aFilename)
>+Exception::GetFilename(nsAString& aFilename)
> {

> void
> Exception::GetFilename(nsString& retval)
> {
Do we really need both these? xpidl method
would work just fine with webidl, or am I missing something here?


>-  nsCString str;
> #ifdef DEBUG
>   DebugOnly<nsresult> rv =
> #endif
>-  GetFilename(str);
>+  GetFilename(retval);
I don't even see why this ends up calling the other GetFilename, especially
in opt builds.




>     JS::FrameDescription& desc = mStackDescription->FrameAt(mIndex);
>     if (JSFlatString *name = desc.funDisplayName()) {
>-      CopyUTF16toUTF8(JS_GetFlatStringChars(name), mFunname);
>+      mFunname.Assign(JS_GetFlatStringChars(name),
>+                      // XXXbz Can't JS_GetStringLength on JSFlatString!
>+                      JS_GetStringLength(JS_FORGET_STRING_FLATNESS(name)));
uh


So if we could have just one GetFilename, r=me

Comment 3

[Boris Zbarsky [:bzbarsky]]

> Not AUTH8String anymore

Done.

> Do we really need both these?

No, good catch.

> I don't even see why this ends up calling the other GetFilename

Even better catch.  It doesn't.  The code doesn't even compile in a debug build...

I've removed the non-XPCOM GetFilename.

> uh

Yeah...

Comment 4

[Boris Zbarsky [:bzbarsky]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/0071ce761fca

Comment 5

[Boris Zbarsky [:bzbarsky]]

And https://hg.mozilla.org/integration/mozilla-inbound/rev/5e3f28be5556 to fix a platform-specific caller.

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/0071ce761fca
https://hg.mozilla.org/mozilla-central/rev/5e3f28be5556