Bug 152203 – CachedScript could have a copy-free path for all-ASCII scripts.

• Component: WebCore JavaScript
• Status: RESOLVED FIXED

[Andreas Kling]

If a script resource consists of nothing but ASCII characters, we could have CachedScript::script() return a String that just wraps the internal SharedBuffer's contents instead of dragging the data through TextDecoder.

[Andreas Kling]

Created attachment 267242 [details]
Patch for EWS

[Andreas Kling]

Created attachment 267254 [details]
Patch

[Andreas Kling]

Created attachment 267256 [details]
Patch

[Antti Koivisto]

Comment on attachment 267256 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=267256&action=review

Nice, r=me

> Source/WebCore/loader/cache/CachedScript.h:65
> +    enum ASCIIResourceOptimizationState { Unknown, Optimized, NotOptimized };
> +    ASCIIResourceOptimizationState m_ASCIIOptimizationState { Unknown };

Maybe this could be more explicit about what "Optimized" means? Something along the lines of DataAndDecodedStringHaveSameBytes.

[Andreas Kling]

Created attachment 267265 [details]
Patch for landing

[WebKit Commit Bot]

Comment on attachment 267265 [details]
Patch for landing

Clearing flags on attachment: 267265

Committed r194017: <http://trac.webkit.org/changeset/194017>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Darin Adler]

Comment on attachment 267256 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=267256&action=review

> Source/WebCore/loader/cache/CachedScript.cpp:74
> +    return encoding == "UTF-8" || encoding == "ISO-8859-1" || encoding == "ASCII";

This seems to be way too conservative. Almost all encodings would answer yes for this. Pretty much everything except for UTF-16 and UTF-32, and I think TextEncoding can answer this question. It's strange to be asking this given just a string rather than TextEncoding.