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

[Deepak Bhole]

* 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
-------------- next part --------------
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;