Bug 128578

Summary: Correct some uses of 'auto'
Product: WebKit Reporter: Brent Fulgham <bfulgham>
Component: WebCore Misc.Assignee: Brent Fulgham <bfulgham>
Status: RESOLVED FIXED    
Severity: Normal CC: aboxhall, andersca, apinheiro, bfulgham, cfleizach, cmarcelo, commit-queue, darin, dmazzoni, esprehn+autocc, glenn, gyuyoung.kim, jamesr, jdiggs, jfernandez, kangil.han, kondapallykalyan, luiz, macpherson, mario, menard, rego, samuel_white, svillar, tonikitoo
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch none

Brent Fulgham
Reported 2014-02-10 21:19:27 PST
I recently noticed a number of places where we were using the following idiom: for (auto rect : dirtyRects) { // ... do some stuff ... } The C++11 standard indicates that this produces something along the lines of: "auto elem = *__begin;" which copies each element. We should prefer to use "for (const auto& ..." wherever possible, or "for (auto&" in cases where we need to modify the elements.
Attachments
Patch (14.73 KB, patch)
2014-02-10 22:16 PST, Brent Fulgham 		no flags
DetailsFormatted DiffDiff
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Brent Fulgham
Comment 1 2014-02-10 22:16:47 PST
Created attachment 223809 [details] Patch
WebKit Commit Bot
Comment 2 2014-02-11 09:31:06 PST
Comment on attachment 223809 [details] Patch Clearing flags on attachment: 223809 Committed r163882: <http://trac.webkit.org/changeset/163882>
WebKit Commit Bot
Comment 3 2014-02-11 09:31:10 PST
All reviewed patches have been landed. Closing bug.
Darin Adler
Comment 4 2014-02-11 12:12:33 PST
I wholeheartedly agree that auto is not good when this churn happens. And I’m really glad you fixed this! I don’t really prefer const auto& over auto&, though. I can’t think of any harm that comes from using auto&. If we only have const access to the collection, then the const works automatically. If we have non-const access, then it doesn’t seem worth the extra word just to narrow the access for the body of the loop.
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