[webkit-dev] About WebKit memory cache

[gaorock]

Hi japhet at chromium.org
Thanks for your reply :)The bug#82287 has been filed.
Best RegardsRock

Date: Mon, 26 Mar 2012 08:44:36 -0700
Subject: Re: [webkit-dev] About WebKit memory cache
From: japhet at chromium.org
To: porgao at hotmail.com
CC: webkit-dev at lists.webkit.org

On Fri, Mar 23, 2012 at 7:48 PM, gaorock <porgao at hotmail.com> wrote:





Hi all
Sometimes I met crashes about memory cache, and I traced them and found a bit doubt:
Should we use typedef HashMap<String, RefPtr<CachedResource>> CachedResourceMap;
instead of typedef HashMap<String, CachedResource*> CachedResourceMap;?
CachedResource doesn't support reference counting in the usual model.  It uses a somewhat confusing set of rules to decide when to delete itself. See canDelete() in CachedResource.h. Figuring out a way to make CachedResource use our normal reference counting model is on my list of things to do someday. :-)
 
The following is the call stack, hope it's useful for you:

 	WebKit.dll!WebCore::ResourceRequestBase::updateResourceRequest()  Line447 + 0x37 byte	C++ 	WebKit.dll!WebCore::ResourceRequestBase::url()  Line123	C++
 	WebKit.dll!WebCore::CachedResource::url()  Line106 + 0x19 byte	C++>	WebKit.dll!WebCore::CachedResourceLoader::requestResource(WebCore::CachedResource::Type type=ImageResource, WebCore::ResourceRequest & request={...}, const WTF::String & charset={...}, const WebCore::ResourceLoaderOptions & options={...}, WebCore::ResourceLoadPriority priority=-1, bool forPreload=false)  Line444 + 0x11 byte	C++
 	WebKit.dll!WebCore::CachedResourceLoader::requestImage(WebCore::ResourceRequest & request={...})  Line160 + 0x21 byte	C++
 	WebKit.dll!WebCore::CSSImageValue::cachedImage(WebCore::CachedResourceLoader * loader=0x00e6e6d8, const WTF::String & url={...})  Line90 + 0xf byte	C++
 	WebKit.dll!WebCore::CSSImageValue::cachedImage(WebCore::CachedResourceLoader * loader=0x00e6e6d8)  Line79 + 0x19 byte	C++
 	WebKit.dll!WebCore::CSSStyleSelector::loadPendingImage(WebCore::StylePendingImage * pendingImage=0x0ada6f30)  Line5306 + 0xc byte	C++
 	WebKit.dll!WebCore::CSSStyleSelector::loadPendingImages()  Line5331 + 0x15 byte	C++ 	WebKit.dll!WebCore::CSSStyleSelector::applyMatchedDeclarations(const WebCore::CSSStyleSelector::MatchResult & matchResult={...})  Line2408	C++
 	WebKit.dll!WebCore::CSSStyleSelector::styleForElement(WebCore::Element * element=0x0ad08088, WebCore::RenderStyle * defaultParent=0x00000000, bool allowSharing=true, bool resolveForRootDefault=false)  Line1310	C++
 	WebKit.dll!WebCore::Element::styleForRenderer()  Line1035 + 0x24 byte	C++ 	WebKit.dll!WebCore::Element::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1059 + 0xc byte	C++
 	WebKit.dll!WebCore::Element::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1138	C++ 	WebKit.dll!WebCore::Element::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1138	C++
 	WebKit.dll!WebCore::Element::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1138	C++ 	WebKit.dll!WebCore::Element::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1138	C++
 	WebKit.dll!WebCore::Element::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1138	C++ 	WebKit.dll!WebCore::Element::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1138	C++
 	WebKit.dll!WebCore::Element::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1138	C++ 	WebKit.dll!WebCore::Element::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1138	C++
 	WebKit.dll!WebCore::Document::recalcStyle(WebCore::Node::StyleChange change=NoChange)  Line1574	C++ 	WebKit.dll!WebCore::Document::updateStyleIfNeeded()  Line1634	C++
 	WebKit.dll!WebCore::Document::updateLayout()  Line1658 + 0x12 byte	C++
In the function of WebCore::ResourceRequestBase::updateResourceRequest(), the point "this" is NOT null, but all of its members are null, so actually it had been freed before. So I think the refCount may be helpful to solve this problem.

This is my first time to write to WebKit-dev, it will be appreciated if someone could give me some instructions or whether I should file a bug for it?

Yes, please file a bug on bugs.webkit.org, and feel free to point me in its direction. 

Thanks in advance!
Best RegardsRock 		 	   		  

_______________________________________________

webkit-dev mailing list

webkit-dev at lists.webkit.org

http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev



 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-dev/attachments/20120327/e3011b13/attachment.html>