From ac2686b3fcfe7964d9ae3da36f75104bf49d247a Mon Sep 17 00:00:00 2001
From: Ben Gruver <bgruv@google.com>
Date: Tue, 9 Apr 2013 23:41:27 -0700
Subject: [PATCH] Add the ability to parse dependencies from odex files

---
 .../dexlib2/dexbacked/DexBackedOdexFile.java  | 28 +++++++++++++++++++
 .../dexlib2/dexbacked/raw/OdexHeaderItem.java |  5 ++++
 2 files changed, 33 insertions(+)

diff --git a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBackedOdexFile.java b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBackedOdexFile.java
index 5a0e9274..11b9daf1 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBackedOdexFile.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBackedOdexFile.java
@@ -33,15 +33,22 @@ package org.jf.dexlib2.dexbacked;
 
 import com.google.common.io.ByteStreams;
 import org.jf.dexlib2.dexbacked.raw.OdexHeaderItem;
+import org.jf.dexlib2.dexbacked.util.VariableSizeList;
 
 import javax.annotation.Nonnull;
 import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
+import java.util.List;
 
 public class DexBackedOdexFile extends DexBackedDexFile {
+    private static final int DEPENDENCY_COUNT_OFFSET = 12;
+    private static final int DEPENDENCY_START_OFFSET = 16;
+
     private final byte[] odexBuf;
 
+
     public DexBackedOdexFile(@Nonnull byte[] odexBuf, byte[] dexBuf) {
         super(dexBuf);
 
@@ -52,6 +59,27 @@ public class DexBackedOdexFile extends DexBackedDexFile {
         return true;
     }
 
+    public List<String> getDependencies() {
+        final int dexOffset = OdexHeaderItem.getDexOffset(odexBuf);
+        final int dependencyOffset = OdexHeaderItem.getDependenciesOffset(odexBuf) - dexOffset;
+
+        BaseDexBuffer buf = new BaseDexBuffer(this.buf);
+        int dependencyCount = buf.readInt(dependencyOffset + DEPENDENCY_COUNT_OFFSET);
+
+        return new VariableSizeList<String>(this, dependencyOffset + DEPENDENCY_START_OFFSET, dependencyCount) {
+            @Override protected String readNextItem(@Nonnull DexReader reader, int index) {
+                int length = reader.readInt();
+                int offset = reader.getOffset();
+                reader.moveRelative(length + 20);
+                try {
+                    return new String(DexBackedOdexFile.this.buf, offset, length-1, "US-ASCII");
+                } catch (UnsupportedEncodingException ex) {
+                    throw new RuntimeException(ex);
+                }
+            }
+        };
+    }
+
     public static DexBackedOdexFile fromInputStream(@Nonnull InputStream is) throws IOException {
         if (!is.markSupported()) {
             throw new IllegalArgumentException("InputStream must support mark");
diff --git a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/raw/OdexHeaderItem.java b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/raw/OdexHeaderItem.java
index b8fe5a59..4e91736f 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/raw/OdexHeaderItem.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/raw/OdexHeaderItem.java
@@ -82,4 +82,9 @@ public class OdexHeaderItem {
         BaseDexBuffer bdb = new BaseDexBuffer(buf);
         return bdb.readSmallUint(DEX_OFFSET);
     }
+
+    public static int getDependenciesOffset(byte[] buf) {
+        BaseDexBuffer bdb = new BaseDexBuffer(buf);
+        return bdb.readSmallUint(DEPENDENCIES_OFFSET);
+    }
 }