Gracefully handle duplicate methods and fields in baksmali

baksmali will emit duplicate methods and fields as commented blocks, when it
is safe to do so.

baksmali/src/main/java/org/jf/baksmali/Adaptors/ClassDefinition.java

@@ -29,6 +29,7 @@
 package org.jf.baksmali.Adaptors;
 
 import org.jf.dexlib.Util.Utf8Utils;
+import org.jf.util.CommentingIndentingWriter;
 import org.jf.util.IndentingWriter;
 import org.jf.dexlib.*;
 import org.jf.dexlib.Code.Analysis.ValidationException;
@@ -208,12 +209,10 @@ public class ClassDefinition {
         writer.write("\n\n");
         writer.write("# static fields\n");
 
-        boolean first = true;
         for (int i=0; i<encodedFields.size(); i++) {
-            if (!first) {
+            if (i > 0) {
                 writer.write('\n');
             }
-            first = false;
 
             ClassDataItem.EncodedField field = encodedFields.get(i);
             EncodedValue encodedValue = null;
@@ -226,10 +225,19 @@ public class ClassDefinition {
                 fieldAnnotations = annotations.getFieldAnnotations(field.field);
             }
 
+            IndentingWriter fieldWriter = writer;
+            // the encoded fields are sorted, so we just have to compare with the previous one to detect duplicates
+            if (i > 0 && field.equals(encodedFields.get(i-1))) {
+                fieldWriter = new CommentingIndentingWriter(writer, "#");
+                fieldWriter.write("Ignoring field with duplicate signature\n");
+                System.err.println(String.format("Warning: class %s has duplicate static field %s, Ignoring.",
+                        classDefItem.getClassType().getTypeDescriptor(), field.field.getShortFieldString()));
+            }
+
             boolean setInStaticConstructor =
                     fieldsSetInStaticConstructor.get(field.field.getIndex()) != null;
 
-            FieldDefinition.writeTo(writer, field, encodedValue, fieldAnnotations, setInStaticConstructor);
+            FieldDefinition.writeTo(fieldWriter, field, encodedValue, fieldAnnotations, setInStaticConstructor);
         }
     }
 
@@ -245,12 +253,12 @@ public class ClassDefinition {
 
         writer.write("\n\n");
         writer.write("# instance fields\n");
-        boolean first = true;
+        for (int i=0; i<encodedFields.size(); i++) {
-        for (ClassDataItem.EncodedField field: encodedFields) {
+            ClassDataItem.EncodedField field = encodedFields.get(i);
-            if (!first) {
+
+            if (i > 0) {
                 writer.write('\n');
             }
-            first = false;
 
             AnnotationSetItem fieldAnnotations = null;
             AnnotationDirectoryItem annotations = classDefItem.getAnnotations();
@@ -258,7 +266,16 @@ public class ClassDefinition {
                 fieldAnnotations = annotations.getFieldAnnotations(field.field);
             }
 
-            FieldDefinition.writeTo(writer, field, null, fieldAnnotations, false);
+            IndentingWriter fieldWriter = writer;
+            // the encoded fields are sorted, so we just have to compare with the previous one to detect duplicates
+            if (i > 0 && field.equals(encodedFields.get(i-1))) {
+                fieldWriter = new CommentingIndentingWriter(writer, "#");
+                fieldWriter.write("Ignoring field with duplicate signature\n");
+                System.err.println(String.format("Warning: class %s has duplicate instance field %s, Ignoring.",
+                        classDefItem.getClassType().getTypeDescriptor(), field.field.getShortFieldString()));
+            }
+
+			FieldDefinition.writeTo(fieldWriter, field, null, fieldAnnotations, false);
         }
     }
 
@@ -294,12 +311,11 @@ public class ClassDefinition {
     }
 
     private void writeMethods(IndentingWriter writer, List<ClassDataItem.EncodedMethod> methods) throws IOException {
-        boolean first = true;
+        for (int i=0; i<methods.size(); i++) {
-        for (ClassDataItem.EncodedMethod method: methods) {
+            ClassDataItem.EncodedMethod method = methods.get(i);
-            if (!first) {
+            if (i > 0) {
                 writer.write('\n');
             }
-            first = false;
 
             AnnotationSetItem methodAnnotations = null;
             AnnotationSetRefList parameterAnnotations = null;
@@ -309,8 +325,17 @@ public class ClassDefinition {
                 parameterAnnotations = annotations.getParameterAnnotations(method.method);
             }
 
+            IndentingWriter methodWriter = writer;
+            // the encoded methods are sorted, so we just have to compare with the previous one to detect duplicates
+            if (i > 0 && method.equals(methods.get(i-1))) {
+                methodWriter = new CommentingIndentingWriter(writer, "#");
+                methodWriter.write("Ignoring method with duplicate signature\n");
+                System.err.println(String.format("Warning: class %s has duplicate method %s, Ignoring.",
+                        classDefItem.getClassType().getTypeDescriptor(), method.method.getShortMethodString()));
+            }
+
             MethodDefinition methodDefinition = new MethodDefinition(method);
-            methodDefinition.writeTo(writer, methodAnnotations, parameterAnnotations);
+            methodDefinition.writeTo(methodWriter, methodAnnotations, parameterAnnotations);
 
             ValidationException validationException = methodDefinition.getValidationException();
             if (validationException != null) {

dexlib/src/main/java/org/jf/dexlib/FieldIdItem.java

@@ -201,6 +201,25 @@ public class FieldIdItem extends Item<FieldIdItem> implements Convertible<FieldI
         return cachedFieldString;
     }
 
+    String cachedShortFieldString = null;
+    /**
+     * @return a "short" string containing just the field name and type, formatted like fieldName:fieldType
+     */
+    public String getShortFieldString() {
+        if (cachedShortFieldString == null) {
+            String fieldName = this.fieldName.getStringValue();
+            String fieldType = this.fieldType.getTypeDescriptor();
+
+            StringBuffer sb = new StringBuffer(fieldName.length() + fieldType.length() + 1);
+            sb.append(fieldName);
+            sb.append(":");
+            sb.append(fieldType);
+            cachedShortFieldString = sb.toString();
+        }
+        return cachedShortFieldString;
+    }
+
+
     /**
      * calculate and cache the hashcode
      */

util/src/main/java/org/jf/util/CommentingIndentingWriter.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2012, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.jf.util;
+
+import java.io.IOException;
+import java.io.Writer;
+
+public class CommentingIndentingWriter extends IndentingWriter {
+    private final String commentStr;
+
+    public CommentingIndentingWriter(Writer writer, String commentStr) {
+        super(writer);
+        this.commentStr = commentStr;
+    }
+
+    protected void writeLineStart() throws IOException {
+        writer.write(commentStr);
+    }
+}

util/src/main/java/org/jf/util/IndentingWriter.java

@@ -32,27 +32,37 @@ import java.io.IOException;
 import java.io.Writer;
 
 public class IndentingWriter extends Writer {
-    private final Writer writer;
+    protected final Writer writer;
-    private final char[] buffer = new char[16];
+    protected final char[] buffer = new char[16];
-    private int indentLevel = 0;
+    protected int indentLevel = 0;
-    private boolean beginningOfLine;
+    private boolean beginningOfLine = true;
     private static final String newLine = System.getProperty("line.separator");
 
     public IndentingWriter(Writer writer) {
         this.writer = writer;
     }
 
+    protected void writeLineStart() throws IOException {
+    }
+
+    protected void writeIndent() throws IOException {
+        for (int i=0; i<indentLevel; i++) {
+            writer.write(' ');
+        }
+    }
+
     @Override
     public void write(int chr) throws IOException {
         //synchronized(lock) {
+            if (beginningOfLine) {
+                writeLineStart();
+            }
             if (chr == '\n') {
                 writer.write(newLine);
                 beginningOfLine = true;
             } else {
                 if (beginningOfLine) {
-                    for (int i=0; i<indentLevel; i++) {
+                    writeIndent();
-                       writer.write(' ');
-                    }
                 }
                 beginningOfLine = false;
                 writer.write(chr);