Merge "Dex merger handles empty sections"

am: eebf335a7f

Change-Id: I29915084793481443cec1c7fd5eeeee3223f7762

2 files changed, 106 insertions, 0 deletions

diff --git a/dx/junit-tests/com/android/dx/merge/DexMergerTest.java b/dx/junit-tests/com/android/dx/merge/DexMergerTest.java
new file mode 100644
index 000000000..b9f03929b
--- /dev/null
+++ b/dx/junit-tests/com/android/dx/merge/DexMergerTest.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.dx.merge;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import com.android.dex.Dex;
+import com.android.dx.command.Main;
+import com.android.dx.command.dexer.DxContext;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+public class DexMergerTest {
+    static class NoFieldsClassA {
+    }
+    static class NoFieldsClassB {
+    }
+
+    @Rule
+    public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+    @Test
+    public void test_merge_dexesWithEmptyFieldsSection() throws IOException {
+        List<Dex> outputDexes = new ArrayList<>();
+        outputDexes.add(getDexForClass(NoFieldsClassA.class));
+        outputDexes.add(getDexForClass(NoFieldsClassB.class));
+
+        Dex merged =
+                new DexMerger(
+                        outputDexes.toArray(new Dex[outputDexes.size()]),
+                        CollisionPolicy.FAIL,
+                        new DxContext())
+                        .merge();
+        assertNotNull(merged);
+        assertNotNull(merged.getTableOfContents());
+        assertEquals(0, merged.getTableOfContents().fieldIds.off);
+    }
+
+    private Dex getDexForClass(Class<?> clazz) throws IOException {
+        String path = clazz.getName().replace('.', '/') + ".class";
+        Path classesJar = temporaryFolder.newFile(clazz.getName() + ".jar").toPath();
+        try (InputStream in = getClass().getClassLoader().getResourceAsStream(path);
+             ZipOutputStream zip = new ZipOutputStream(Files.newOutputStream(classesJar))) {
+
+            ZipEntry entry = new ZipEntry(path);
+            zip.putNextEntry(entry);
+            zip.write(readEntireStream(in));
+            zip.closeEntry();
+        }
+
+        Path output = temporaryFolder.newFolder().toPath();
+        Main.main(new String[]{"--dex", "--output=" + output.toString(), classesJar.toString()});
+
+        return new Dex(Files.readAllBytes(output.resolve("classes.dex")));
+    }
+
+    private static byte[] readEntireStream(InputStream inputStream) throws IOException {
+        ByteArrayOutputStream bytesOut = new ByteArrayOutputStream();
+        byte[] buffer = new byte[8192];
+
+        int count;
+        while ((count = inputStream.read(buffer)) != -1) {
+            bytesOut.write(buffer, 0, count);
+        }
+
+        return bytesOut.toByteArray();
+    }
+}
diff --git a/dx/src/com/android/dx/merge/DexMerger.java b/dx/src/com/android/dx/merge/DexMerger.java
index 470d8fb22..81ad2ddb7 100644
--- a/dx/src/com/android/dx/merge/DexMerger.java
+++ b/dx/src/com/android/dx/merge/DexMerger.java
@@ -166,6 +166,9 @@ public final class DexMerger {
         unionAnnotationSetsAndDirectories();
         mergeClassDefs();
 
+        // computeSizesFromOffsets expects sections sorted by offset, so make it so
+        Arrays.sort(contentsOut.sections);
+
         // write the header
         contentsOut.header.off = 0;
         contentsOut.header.size = 1;
@@ -255,6 +258,11 @@ public final class DexMerger {
                 offsets[i] = readIntoMap(
                         dexSections[i], sections[i], indexMaps[i], indexes[i], values, i);
             }
+            if (values.isEmpty()) {
+                getSection(contentsOut).off = 0;
+                getSection(contentsOut).size = 0;
+                return;
+            }
             getSection(contentsOut).off = out.getPosition();
 
             int outCount = 0;
@@ -299,6 +307,11 @@ public final class DexMerger {
             for (int i = 0; i < dexes.length; i++) {
                 all.addAll(readUnsortedValues(dexes[i], indexMaps[i]));
             }
+            if (all.isEmpty()) {
+                getSection(contentsOut).off = 0;
+                getSection(contentsOut).size = 0;
+                return;
+            }
             Collections.sort(all);
 
             int outCount = 0;