[icedtea-web] RFC: Patch to correct classloader sharing rules

[Dr Andrew John Hughes]

On 12:30 Mon 28 Mar     , Deepak Bhole wrote:
> * Dr Andrew John Hughes <ahughes at redhat.com> [2011-03-25 20:43]:
> > On 19:43 Fri 25 Mar     , Deepak Bhole wrote:
> > > Hi,
> > > 
> > > Omair found a page earlier that specifies some rules on plugin classloader
> > > sharing. Currently we share it based on site address -- attached patch fixes
> > > that to do it as per the proprietary plugin rules:
> > > http://download.oracle.com/javase/6/docs/technotes/guides/deployment/deployment-guide/applet-compatibility.html
> > > 
> > > ChangeLog:
> > > 2011-03-25  Deepak Bhole <dbhole at redhat.com>
> > > 
> > >     * netx/net/sourceforge/jnlp/PluginBridge.java
> > >     (PluginBridge): Construct unique key based on a combination of codebase, 
> > >     cache_archive, java_archive, and archive. This automatically ensures are 
> > >     loaders are shared only when appropriate.
> > > 
> > > Cheers,
> > > Deepak
> > 
> > AFAICS, atts is a hashtable with generic types so the casts don't need to be there.
> > 
> 
> Doh! Didn't even think to check for generics.. just went with old habit
> of casting :/ Fixed now.
> 
> > Some of the lines seem too long.  I guess there isn't much that can be done
> > with the URL, but the later comments and the String assignments could certainly
> > be split.
> > 
> 
> Fixed as well. New patch okay?
> 
> Cheers,
> Deepak

Looks good, thanks.  Please commit.

> diff -r 92486f15be36 netx/net/sourceforge/jnlp/PluginBridge.java
> --- a/netx/net/sourceforge/jnlp/PluginBridge.java	Thu Mar 24 09:34:51 2011 -0400
> +++ b/netx/net/sourceforge/jnlp/PluginBridge.java	Mon Mar 28 12:27:24 2011 -0400
> @@ -132,10 +132,33 @@
>          else
>              security = null;
>  
> -        // Plugin needs to share classloaders so that applet instances from 
> -        // same page can communicate (there are applets known to require 
> -        // such communication for proper functionality)
> -        this.uniqueKey = documentBase.toString();
> +        /* According to http://download.oracle.com/javase/6/docs/technotes/guides/deployment/deployment-guide/applet-compatibility.html, 
> +         * classloaders are shared iff these properties match:
> +         * codebase, cache_archive, java_archive, archive
> +         * 
> +         * To achieve this, we create the uniquekey based on those 4 values,
> +         * always in the same order. The initial "<NAME>=" parts ensure a 
> +         * bad tag cannot trick the loader into getting shared with another.
> +         */
> +
> +        // Firefox sometimes skips the codebase if it is default  -- ".", 
> +        // so set it that way if absent
> +        String codebaseAttr =      atts.get("codebase") != null ?
> +                                   atts.get("codebase") : ".";
> +
> +        String cache_archiveAttr = atts.get("cache_archive") != null ? 
> +                                   atts.get("cache_archive") : "";
> +
> +        String java_archiveAttr =  atts.get("java_archive") != null ? 
> +                                   atts.get("java_archive") : "";
> +
> +        String archiveAttr =       atts.get("archive") != null ? 
> +                                   atts.get("archive") : "";
> +
> +        this.uniqueKey = "codebase=" + codebaseAttr +
> +                         "cache_archive=" + cache_archiveAttr + 
> +                         "java_archive=" + java_archiveAttr + 
> +                         "archive=" +  archiveAttr;
>  
>          usePack = false;
>          useVersion = false;


-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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