[jboss-svn-commits] JBL Code SVN: r29293 - in labs/jbosstm/workspace/adinn/byteman/trunk/src/org/jboss/byteman/rule: expression and 1 other directory.

[jboss-svn-commits at lists.jboss.org]

Author: adinn
Date: 2009-09-10 09:06:33 -0400 (Thu, 10 Sep 2009)
New Revision: 29293

Modified:
   labs/jbosstm/workspace/adinn/byteman/trunk/src/org/jboss/byteman/rule/RuleElement.java
   labs/jbosstm/workspace/adinn/byteman/trunk/src/org/jboss/byteman/rule/expression/StringPlusExpression.java
Log:
String plus now substitutes null for null operands -- fixes BYTEMAN-31

Modified: labs/jbosstm/workspace/adinn/byteman/trunk/src/org/jboss/byteman/rule/RuleElement.java
===================================================================
--- labs/jbosstm/workspace/adinn/byteman/trunk/src/org/jboss/byteman/rule/RuleElement.java	2009-09-10 12:39:35 UTC (rev 29292)
+++ labs/jbosstm/workspace/adinn/byteman/trunk/src/org/jboss/byteman/rule/RuleElement.java	2009-09-10 13:06:33 UTC (rev 29293)
@@ -33,6 +33,7 @@
 import org.jboss.byteman.rule.helper.HelperAdapter;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.Label;
 
 import java.io.StringWriter;
 
@@ -204,8 +205,20 @@
     {
         assert toType == Type.STRING;
         if (fromType.isObject() || fromType.isArray()) {
-            // use the toString method
+            // use the toString method if the object is non null otherwise just replace it with null
+            Label elseLabel = new Label();
+            Label endLabel = new Label();
+            // if (object == null)
+            mv.visitInsn(Opcodes.DUP);
+            mv.visitJumpInsn(Opcodes.IFNONNULL, elseLabel);
+            // then string = "null"
+            mv.visitInsn(Opcodes.POP);
+            mv.visitLdcInsn("null");
+            mv.visitJumpInsn(Opcodes.GOTO, endLabel);
+            // else string = object.toString()
+            mv.visitLabel(elseLabel);
             mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Object", "toString", "()Ljava/lang/String;");
+            mv.visitLabel(endLabel);
         } else if (fromType == Type.Z) {
             // use the toString method
             mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Boolean", "toString", "(Z)Ljava/lang/String;");

Modified: labs/jbosstm/workspace/adinn/byteman/trunk/src/org/jboss/byteman/rule/expression/StringPlusExpression.java
===================================================================
--- labs/jbosstm/workspace/adinn/byteman/trunk/src/org/jboss/byteman/rule/expression/StringPlusExpression.java	2009-09-10 12:39:35 UTC (rev 29292)
+++ labs/jbosstm/workspace/adinn/byteman/trunk/src/org/jboss/byteman/rule/expression/StringPlusExpression.java	2009-09-10 13:06:33 UTC (rev 29293)
@@ -33,6 +33,7 @@
 import org.jboss.byteman.rule.grammar.ParseNode;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.Label;
 
 /**
  * A binary string concatenation operator expression
@@ -60,7 +61,7 @@
         Object value1 = getOperand(0).interpret(helper);
         Object value2 = getOperand(1).interpret(helper);
         String string1 = value1.toString();
-        String string2 = value2.toString();
+        String string2 = (value2 == null ? "null" : value2.toString());
         return string1 + string2;
     }
 
@@ -72,7 +73,9 @@
         int currentStack = currentStackHeights.stackCount;
         int expected = 2;
 
-        // compile and type convert each operand
+        // compile and type convert each operand n.b. the type conversion will ensure that
+        // null operands are replaced with "null"
+        
         oper0.compile(mv, currentStackHeights, maxStackHeights);
         compileTypeConversion(oper0.getType(), type, mv, currentStackHeights, maxStackHeights);
         oper1.compile(mv, currentStackHeights, maxStackHeights);
@@ -82,6 +85,7 @@
         // by employing a StringBuffer but for now we will just evaluate the left and right operand and
         // then call concat to join them
         // add two strings leaving one string
+
         expected = 1;
         mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/String", "concat", "(Ljava/lang/String;)Ljava/lang/String;");