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

[Deepak Bhole]

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
-------------- 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	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;