Merge pull request #29 from riboribo/master

Extended convertInvoke to support more StringBuilder formats

jadx-core/src/main/java/jadx/core/dex/visitors/SimplifyVisitor.java

@@ -5,6 +5,7 @@ import jadx.core.dex.info.FieldInfo;
 import jadx.core.dex.info.MethodInfo;
 import jadx.core.dex.instructions.ArithNode;
 import jadx.core.dex.instructions.ArithOp;
+import jadx.core.dex.instructions.ConstStringNode;
 import jadx.core.dex.instructions.IfNode;
 import jadx.core.dex.instructions.IndexInsnNode;
 import jadx.core.dex.instructions.InsnType;
@@ -134,30 +135,65 @@ public class SimplifyVisitor extends AbstractVisitor {
 	}
 
 	private static InsnNode convertInvoke(MethodNode mth, InsnNode insn) {
-		MethodInfo callMth = ((InvokeNode) insn).getCallMth();
-		if (callMth.getDeclClass().getFullName().equals(Consts.CLASS_STRING_BUILDER)
-				&& callMth.getShortId().equals(Consts.MTH_TOSTRING_SIGNATURE)
-				&& insn.getArg(0).isInsnWrap()) {
-			try {
-				List<InsnNode> chain = flattenInsnChain(insn);
-				if (chain.size() > 1 && chain.get(0).getType() == InsnType.CONSTRUCTOR) {
-					ConstructorInsn constr = (ConstructorInsn) chain.get(0);
-					if (constr.getClassType().getFullName().equals(Consts.CLASS_STRING_BUILDER)
-							&& constr.getArgsCount() == 0) {
-						int len = chain.size();
-						InsnNode concatInsn = new InsnNode(InsnType.STR_CONCAT, len - 1);
-						for (int i = 1; i < len; i++) {
-							concatInsn.addArg(chain.get(i).getArg(1));
-						}
-						concatInsn.setResult(insn.getResult());
-						return concatInsn;
-					}
-				}
-			} catch (Throwable e) {
-				LOG.debug("Can't convert string concatenation: {} insn: {}", mth, insn, e);
-			}
-		}
-		return null;
+          MethodInfo callMth = ((InvokeNode) insn).getCallMth();
+
+          // If this is a 'new StringBuilder(xxx).append(yyy).append(zzz).toString(), 
+          // convert it to STRING_CONCAT pseudo instruction.
+          if (callMth.getDeclClass().getFullName().equals(Consts.CLASS_STRING_BUILDER)
+              && callMth.getShortId().equals(Consts.MTH_TOSTRING_SIGNATURE)
+              && insn.getArg(0).isInsnWrap()) {
+            try {
+              List<InsnNode> chain = flattenInsnChain(insn);
+              int constrIndex = -1;  //RAF
+              // Case where new StringBuilder() is called with NO args (the entire
+              // string is created using .append() calls:
+              if (chain.size()>1 && chain.get(0).getType()==InsnType.CONSTRUCTOR) {
+                constrIndex = 0;
+              } else if (chain.size()>2 && chain.get(1).getType()==InsnType.CONSTRUCTOR) {
+                //RAF Case where the first string element is String arg to the 
+                // new StringBuilder("xxx") constructor
+                constrIndex = 1;
+              } else if (chain.size()>3 && chain.get(2).getType()==InsnType.CONSTRUCTOR) {
+                //RAF Case where the first string element is String.valueOf() arg 
+                // to the new StringBuilder(String.valueOf(zzz)) constructor
+                constrIndex = 2;
+              }
+
+              if (constrIndex != -1) {  // If we found a CONSTRUCTOR, is it a StringBuilder?
+                ConstructorInsn constr = (ConstructorInsn) chain.get(constrIndex);
+                if (constr.getClassType().getFullName().equals(Consts.CLASS_STRING_BUILDER)) {
+                  int len = chain.size(),  argInd = 1;
+                  InsnNode concatInsn = new InsnNode(InsnType.STR_CONCAT, len-1);
+                  InsnNode argInsn;
+                  if (constrIndex > 0) {  // There was an arg to the StringBuilder constr
+                    InsnWrapArg iwa;
+                    if (constrIndex==2 
+                        && (argInsn = chain.get(1)).getType()==InsnType.INVOKE
+                        && ((InvokeNode)argInsn).getCallMth().getName().compareTo("valueOf")==0) {
+                      // The argument of new StringBuilder() is a String.valueOf(chainElement0)
+                      iwa = (InsnWrapArg)argInsn.getArg(0);
+                      argInd = 3;  // Cause for loop below to skip to after the constructor
+                    } else {
+                      ConstStringNode csn = (ConstStringNode)chain.get(0);
+                      iwa = new InsnWrapArg(csn);
+                      argInd = 2;  // Cause for loop below to skip to after the constructor
+                    }
+                    concatInsn.addArg(iwa);
+                  }
+
+                  for (; argInd < len; argInd++) {  // Add the .append(xxx) arg string to concat 
+                    concatInsn.addArg(chain.get(argInd).getArg(1));
+                  }
+                  concatInsn.setResult(insn.getResult());
+                  return concatInsn;
+                } // end of if constructor is for StringBuilder
+              } // end of if we found a constructor early in the chain
+
+            } catch (Throwable e) {
+              LOG.debug("Can't convert string concatenation: {} insn: {}", mth, insn, e);
+            }
+          }
+          return null;
 	}
 
 	private static InsnNode simplifyArith(InsnNode insn) {
@@ -253,4 +289,4 @@ public class SimplifyVisitor extends AbstractVisitor {
 		Collections.reverse(chain);
 		return chain;
 	}
-}
+}
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