String concatenation visitor: fix for ArrayIndexOutOfBoundsException

build.gradle

@@ -1,6 +1,6 @@
 plugins {
     id 'com.github.ksoichiro.console.reporter' version '0.5.0'
-    id 'org.sonarqube' version '2.6.2'
+    id 'org.sonarqube' version '2.7'
     id 'com.github.ben-manes.versions' version '0.20.0'
 }
 
@@ -41,10 +41,9 @@ allprojects {
 
         testCompile 'ch.qos.logback:logback-classic:1.2.3'
         testCompile 'junit:junit:4.12'
-        testCompile 'org.hamcrest:hamcrest-library:1.3'
-        testCompile 'org.mockito:mockito-core:2.20.1'
+        testCompile 'org.hamcrest:hamcrest-library:2.1'
+        testCompile 'org.mockito:mockito-core:2.23.4'
         testCompile 'org.spockframework:spock-core:1.1-groovy-2.4'
-        testCompile 'cglib:cglib-nodep:3.2.7'
     }
 
     repositories {

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.9-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.1.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

jadx-core/build.gradle

@@ -5,13 +5,13 @@ dependencies {
 
     compile files('lib/dx-1.16.jar')
     compile 'commons-io:commons-io:2.6'
-    compile 'org.ow2.asm:asm:6.2'
-    compile 'org.jetbrains:annotations:16.0.2'
-    compile 'uk.com.robust-it:cloning:1.9.10'
+    compile 'org.ow2.asm:asm:7.0'
+    compile 'org.jetbrains:annotations:16.0.3'
+    compile 'uk.com.robust-it:cloning:1.9.11'
 
-    testCompile 'org.smali:smali:2.2.4'
-    testCompile 'org.smali:baksmali:2.2.4'
+    testCompile 'org.smali:smali:2.2.5'
+    testCompile 'org.smali:baksmali:2.2.5'
 
-    testCompile 'org.apache.commons:commons-lang3:3.7'
+    testCompile 'org.apache.commons:commons-lang3:3.8.1'
 }
 

jadx-core/src/main/java/jadx/core/dex/instructions/CallMthInterface.java

@@ -0,0 +1,8 @@
+package jadx.core.dex.instructions;
+
+import jadx.core.dex.info.MethodInfo;
+
+public interface CallMthInterface {
+
+	public MethodInfo getCallMth();
+}

jadx-core/src/main/java/jadx/core/dex/instructions/InvokeNode.java

@@ -9,7 +9,7 @@
 import jadx.core.utils.InsnUtils;
 import jadx.core.utils.Utils;
 
-public class InvokeNode extends InsnNode {
+public class InvokeNode extends InsnNode implements CallMthInterface {
 
 	private final InvokeType type;
 	private final MethodInfo mth;

jadx-core/src/main/java/jadx/core/dex/instructions/mods/ConstructorInsn.java

@@ -2,13 +2,14 @@
 
 import jadx.core.dex.info.ClassInfo;
 import jadx.core.dex.info.MethodInfo;
+import jadx.core.dex.instructions.CallMthInterface;
 import jadx.core.dex.instructions.InsnType;
 import jadx.core.dex.instructions.InvokeNode;
 import jadx.core.dex.instructions.args.RegisterArg;
 import jadx.core.dex.nodes.InsnNode;
 import jadx.core.dex.nodes.MethodNode;
 
-public class ConstructorInsn extends InsnNode {
+public class ConstructorInsn extends InsnNode implements CallMthInterface {
 
 	private final MethodInfo callMth;
 	private final CallType callType;

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

@@ -4,19 +4,13 @@
 import java.util.Collections;
 import java.util.List;
 
+import jadx.core.dex.instructions.*;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import jadx.core.Consts;
 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;
-import jadx.core.dex.instructions.InvokeNode;
 import jadx.core.dex.instructions.args.ArgType;
 import jadx.core.dex.instructions.args.FieldArg;
 import jadx.core.dex.instructions.args.InsnArg;
@@ -148,6 +142,15 @@ private static void simplifyTernary(TernaryInsn insn) {
 		}
 	}
 
+	/**
+	 * Simplify chains of calls to StringBuilder#append() plus constructor of StringBuilder.
+	 * Those chains are usually automatically generated by the Java compiler when you create String
+	 * concatenations like <code>"text " + 1 + " text"</code>.
+	 *
+	 * @param mth
+	 * @param insn
+	 * @return
+	 */
 	private static InsnNode convertInvoke(MethodNode mth, InsnNode insn) {
 		MethodInfo callMth = ((InvokeNode) insn).getCallMth();
 
@@ -201,7 +204,15 @@ private static InsnNode convertInvoke(MethodNode mth, InsnNode insn) {
 						}
 
 						for (; argInd < len; argInd++) {  // Add the .append(xxx) arg string to concat
-							concatInsn.addArg(chain.get(argInd).getArg(1));
+							InsnNode node = chain.get(argInd);
+							MethodInfo method = ((CallMthInterface) node).getCallMth();
+							if (!(node.getArgsCount() < 2 && method.isConstructor() || method.getName().equals("append"))) {
+								// The chain contains other calls to StringBuilder methods than the constructor or append.
+								// We can't simplify such chains, therefore we leave them as they are.
+								return null;
+							}
+							// process only constructor and append() calls
+							concatInsn.addArg(node.getArg(1));
 						}
 						concatInsn.setResult(insn.getResult());
 						return concatInsn;

jadx-core/src/test/java/jadx/tests/api/utils/CountString.java

@@ -1,33 +1,34 @@
 package jadx.tests.api.utils;
 
 import org.hamcrest.Description;
-import org.hamcrest.core.SubstringMatcher;
+import org.hamcrest.TypeSafeMatcher;
 
-public class CountString extends SubstringMatcher {
+public class CountString extends TypeSafeMatcher<String> {
 
 	private final int count;
+	private final String substring;
 
 	public CountString(int count, String substring) {
-		super(substring);
 		this.count = count;
+		this.substring = substring;
 	}
 
 	@Override
-	protected boolean evalSubstringOf(String string) {
-		return this.count == count(string);
+	protected boolean matchesSafely(String item) {
+		return this.count == count(item);
 	}
 
 	@Override
-	protected String relationship() {
-		return "containing <" + count + "> occurrence of";
+	public void describeMismatchSafely(String item, Description mismatchDescription) {
+		mismatchDescription.appendText("found ").appendValue(count(item));
 	}
 
 	@Override
-	public void describeMismatchSafely(String item, Description mismatchDescription) {
-		mismatchDescription.appendText("found ").appendValue(count(item));
+	public void describeTo(Description description) {
+		description.appendText("containing <" + count + "> occurrence of ").appendValue(this.substring);
 	}
 
 	private int count(String string) {
-		return TestUtils.count(string, substring);
+		return TestUtils.count(string, this.substring);
 	}
 }

jadx-core/src/test/java/jadx/tests/integration/SimplifyVisitorStringBuilderTest.java

@@ -0,0 +1,94 @@
+package jadx.tests.integration;
+
+import jadx.core.dex.nodes.ClassNode;
+import jadx.core.dex.visitors.SimplifyVisitor;
+import jadx.core.utils.exceptions.JadxException;
+import jadx.tests.api.IntegrationTest;
+import org.junit.Test;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Test the StringBuilder simplification part of {@link SimplifyVisitor}
+ *
+ * @author Jan Peter Stotz
+ */
+public class SimplifyVisitorStringBuilderTest extends IntegrationTest {
+
+	public static class TestCls1 {
+		public String test() {
+			return new StringBuilder("[init]").append("a1").append('c').append(2).append(0l).append(1.0f).
+					append(2.0d).append(true).toString();
+		}
+	}
+
+	@Test
+	public void test1() throws JadxException {
+		ClassNode cls = getClassNode(SimplifyVisitorStringBuilderTest.TestCls1.class);
+		SimplifyVisitor visitor = new SimplifyVisitor();
+		visitor.visit(cls);
+		String code = cls.getCode().toString();
+		assertThat(code, containsString("return \"[init]\" + \"a1\" + 'c' + 2 + 0 + 1.0f + 2.0d + true;"));
+	}
+
+	public static class TestCls2 {
+		public String test() {
+			// A chain with non-final variables
+			String sInit = "[init]";
+			String s = "a1";
+			char c = 'c';
+			int i = 1;
+			long l = 2;
+			float f = 1.0f;
+			double d = 2.0d;
+			boolean b = true;
+			return new StringBuilder(sInit).append(s).append(c).append(i).append(l).append(f).
+					append(d).append(b).toString();
+		}
+	}
+
+	@Test
+	public void test2() throws JadxException {
+		ClassNode cls = getClassNode(SimplifyVisitorStringBuilderTest.TestCls2.class);
+		SimplifyVisitor visitor = new SimplifyVisitor();
+		visitor.visit(cls);
+		String code = cls.getCode().toString();
+		assertThat(code, containsString("return \"[init]\" + \"a1\" + 'c' + 1 + 2 + 1.0f + 2.0d + true;"));
+	}
+
+	public static class TestClsStringUtilsReverse {
+
+		/**
+		 * Simplified version of org.apache.commons.lang3.StringUtils.reverse()
+		 */
+		public static String reverse(final String str) {
+			return new StringBuilder(str).reverse().toString();
+		}
+	}
+
+	@Test
+	public void test3() throws JadxException {
+		ClassNode cls = getClassNode(SimplifyVisitorStringBuilderTest.TestClsStringUtilsReverse.class);
+		SimplifyVisitor visitor = new SimplifyVisitor();
+		visitor.visit(cls);
+		String code = cls.getCode().toString();
+		assertThat(code, containsString("return new StringBuilder(str).reverse().toString();"));
+	}
+
+	public static class TestClsChainWithDelete {
+		public String test() {
+			// a chain we can't simplify
+			return new StringBuilder("[init]").append("a1").delete(1, 2).toString();
+		}
+	}
+
+	@Test
+	public void testChainWithDelete() throws JadxException {
+		ClassNode cls = getClassNode(TestClsChainWithDelete.class);
+		SimplifyVisitor visitor = new SimplifyVisitor();
+		visitor.visit(cls);
+		String code = cls.getCode().toString();
+		assertThat(code, containsString("return new StringBuilder(\"[init]\").append(\"a1\").delete(1, 2).toString();"));
+	}
+}

jadx-gui/build.gradle

@@ -10,15 +10,15 @@ mainClassName = 'jadx.gui.JadxGUI'
 dependencies {
     compile(project(":jadx-core"))
     compile(project(":jadx-cli"))
-    compile 'com.fifesoft:rsyntaxtextarea:2.6.1'
+    compile 'com.fifesoft:rsyntaxtextarea:3.0.0'
     compile 'com.google.code.gson:gson:2.8.5'
     compile files('libs/jfontchooser-1.0.5.jar')
     compile 'hu.kazocsaba:image-viewer:1.2.3'
 
-    compile 'org.apache.commons:commons-lang3:3.7'
+    compile 'org.apache.commons:commons-lang3:3.8.1'
 
-    compile 'io.reactivex.rxjava2:rxjava:2.1.17'
-    compile "com.github.akarnokd:rxjava2-swing:0.2.16"
+    compile 'io.reactivex.rxjava2:rxjava:2.2.5'
+    compile "com.github.akarnokd:rxjava2-swing:0.3.3"
 }
 
 applicationDistribution.with {