Re: Illegal Package-Private Accesses Yet Again!

[Ranjit Mathew <rmathew at hotmail dot com>]

Andrew Haley wrote:
> Ranjit Mathew writes:
>  > Hi,
>  > 
>  >     Here's the promised follow up patch to my previous mail that
>  > temporarily avoids illegal package-private accesses in libgcj.
>  > 
>  > Please, please, *PLEASE* let us apply this (or something 
>  > similar)!
> 
> Why not just make a few native access methods for the package private
> members.

Ok. Attached is my attempt at avoiding these problems
in a different manner.

First, I note that StackTraceElement and NameFinder are in
the same package and NameFinder.lookup() is called only
by java.lang.VMThrowable - so I modified lookup( ) to
directly take in a StackTraceElement.

(BTW, VMThrowable's header indicates that it is a part of
GNU Classpath, but I could not find it there. :-/)

Second, I created a passthrough native helper method
in natNameFinder.cc to call the package-private constructor
in java.lang.StackTraceElement.

Does this look better?

(It survived a clean-build of libgcj with my package-private
patch applied to GCJ and the testsuite showed no new failures.)

Ranjit.

Index: ChangeLog
from  Ranjit Mathew  <rmathew@hotmail.com>

        * java/lang/VMThrowable.java (getStackTrace): Pass trace as is to
        modified lookup().
        * gnu/gcj/runtime/NameFinder.java (lookup): Change to take in a
        StackTraceElement directly.
        (newElement): New native helper method to create StackTraceElement
        bypassing Java access control.
        (createStackTraceElement): Use newElement() instead of directly
        calling StackTraceElement's constructor.
        * gnu/gcj/runtime/natNameFinder.cc (newElement): New method.

Index: java/lang/VMThrowable.java
===================================================================
--- java/lang/VMThrowable.java	2004-03-30 16:17:28.000000000 +0530
+++ java/lang/VMThrowable.java	2004-03-30 16:43:36.000000000 +0530
@@ -96,8 +96,7 @@ final class VMThrowable
     if (trace != null)
       {
 	NameFinder nameFinder = new NameFinder();
-	result = nameFinder.lookup(t, trace.stackTraceAddrs(),
-				   trace.length());
+	result = nameFinder.lookup(t, trace);
 	nameFinder.close();
       }
     else
Index: gnu/gcj/runtime/NameFinder.java
===================================================================
--- gnu/gcj/runtime/NameFinder.java	2004-03-30 16:14:06.000000000 +0530
+++ gnu/gcj/runtime/NameFinder.java	2004-03-30 17:59:53.000000000 +0530
@@ -241,8 +241,11 @@ public class NameFinder
    * Given an Throwable and a native stacktrace returns an array of
    * StackTraceElement containing class, method, file and linenumbers.
    */
-  public StackTraceElement[] lookup(Throwable t, RawData addrs, int length)
+  public StackTraceElement[] lookup(Throwable t, StackTrace trace)
   {
+    RawData addrs = trace.stackTraceAddrs();
+    int length = trace.length();
+
     StackTraceElement[] elements = new StackTraceElement[length];
     for (int i=0; i < length; i++)
       elements[i] = lookup(addrs, i);
@@ -353,6 +356,16 @@ public class NameFinder
   }

   /**
+   * Native helper method to create a StackTraceElement. Needed to work
+   * around normal Java access restrictions.
+   */
+  native private StackTraceElement newElement(String fileName,
+                                              int lineNumber,
+                                              String className,
+                                              String methName,
+                                              boolean isNative);
+
+  /**
    * Creates a StackTraceElement given a string and a filename.
    * Splits the given string into the class and method part.
    * The string name will be a demangled to a fully qualified java method
@@ -363,7 +376,7 @@ public class NameFinder
   private StackTraceElement createStackTraceElement(String name, String file)
   {
     if (!demangle)
-      return new StackTraceElement(file, -1, null, name, false);
+      return newElement(file, -1, null, name, false);

     String s = demangleName(name);
     String methodName = s;
@@ -409,7 +422,7 @@ public class NameFinder
 	  }
       }

-    return new StackTraceElement(fileName, line, className, methodName, false);
+    return newElement(fileName, line, className, methodName, false);
   }

   /**
Index: gnu/gcj/runtime/natNameFinder.cc
===================================================================
--- gnu/gcj/runtime/natNameFinder.cc	2004-03-30 17:09:43.000000000 +0530
+++ gnu/gcj/runtime/natNameFinder.cc	2004-03-30 18:00:23.000000000 +0530
@@ -48,6 +48,17 @@ details.  */

 #endif /* ! __USER_LABEL_PREFIX__ */

+java::lang::StackTraceElement*
+gnu::gcj::runtime::NameFinder::newElement (java::lang::String* fileName,
+                                           jint lineNumber,
+                                           java::lang::String* className,
+                                           java::lang::String* methName,
+                                           jboolean isNative)
+{
+  return new java::lang::StackTraceElement( fileName, lineNumber,
+                                            className, methName, isNative);
+}
+
 java::lang::String*
 gnu::gcj::runtime::NameFinder::getExternalLabel (java::lang::String* name)
 {