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

[Dr Andrew John Hughes]

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.

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.

> 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	Fri Mar 25 19:36:54 2011 -0400
> @@ -132,10 +132,23 @@
>          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 tag cannot "trick" the loader into getting shared with another
> +         */
> +        
> +        String codebaseAttr = atts.get("codebase") != null ? (String) atts.get("codebase") : "."; // codebase default is "."
> +        String cache_archiveAttr = atts.get("cache_archive") != null ? (String) atts.get("cache_archive") : "";
> +        String java_archiveAttr = atts.get("java_archive") != null ? (String) atts.get("java_archive") : "";
> +        String archiveAttr = atts.get("archive") != null ? (String) 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)

Support Free Java!
Contribute to GNU Classpath and IcedTea
http://www.gnu.org/software/classpath
http://icedtea.classpath.org
PGP Key: F5862A37 (https://keys.indymedia.org/)
Fingerprint = EA30 D855 D50F 90CD F54D  0698 0713 C3ED F586 2A37