Truncate the filename for overly long class names

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

@@ -31,6 +31,7 @@ package org.jf.util;
 import ds.tree.RadixTree;
 import ds.tree.RadixTreeImpl;
 
+import javax.annotation.Nonnull;
 import java.io.*;
 import java.nio.CharBuffer;
 import java.util.regex.Pattern;
@@ -41,6 +42,9 @@ import java.util.regex.Pattern;
  * class name to distinguish it from another class with a name that differes only by case. i.e. a.smali and a_2.smali
  */
 public class ClassFileNameHandler {
+    // we leave an extra 10 characters to allow for a numeric suffix to be added, if it's needed
+    private static final int MAX_FILENAME_LENGTH = 245;
+
     private PackageNameEntry top;
     private String fileExtension;
     private boolean modifyWindowsReservedFilenames;
@@ -83,6 +87,10 @@ public class ClassFileNameHandler {
                     packageElement += "#";
                 }
 
+                if (packageElement.length() > MAX_FILENAME_LENGTH) {
+                    packageElement = shortenPathComponent(packageElement, MAX_FILENAME_LENGTH);
+                }
+
                 packageElements[elementIndex++] = packageElement;
                 elementStart = ++i;
             }
@@ -101,11 +109,23 @@ public class ClassFileNameHandler {
             packageElement += "#";
         }
 
+        if ((packageElement.length() + fileExtension.length()) > MAX_FILENAME_LENGTH) {
+            packageElement = shortenPathComponent(packageElement, MAX_FILENAME_LENGTH - fileExtension.length());
+        }
+
         packageElements[elementIndex] = packageElement;
 
         return top.addUniqueChild(packageElements, 0);
     }
 
+    @Nonnull
+    static String shortenPathComponent(@Nonnull String pathComponent, int maxLength) {
+        int toRemove = pathComponent.length() - maxLength + 1;
+
+        int firstIndex = (pathComponent.length()/2) - (toRemove/2);
+        return pathComponent.substring(0, firstIndex) + "#" + pathComponent.substring(firstIndex+toRemove);
+    }
+
     private static boolean testForWindowsReservedFileNames(File path) {
         File f = new File(path, "aux.smali");
         if (f.exists()) {
@@ -242,7 +262,6 @@ public class ClassFileNameHandler {
                 }
             }
 
-
             if (pathElementsIndex == pathElements.length - 1) {
                 String fileName;
                 if (!isCaseSensitive()) {

util/src/test/java/org/jf/util/ClassFileNameHandlerTest.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2013, 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 junit.framework.Assert;
+import org.junit.Test;
+
+public class ClassFileNameHandlerTest {
+    @Test
+    public void testShortedPathComponent() {
+        StringBuilder sb = new StringBuilder();
+        for (int i=0; i<300; i++) {
+            sb.append((char)i);
+        }
+
+        String result = ClassFileNameHandler.shortenPathComponent(sb.toString(), 255);
+
+        Assert.assertEquals(255, result.length());
+    }
+}