Ports DiffScriptBackupWriter from gmscore to AOSP.

A few additional changes (apart from style and usual dependencies) were
needed:
- Additional dependencies (not part of Backup & Restore code) were
ported over:
	- ByteRange
	- DiffScriptWriter
	- OutputStreamWrapper
	- SingleStreamDiffScriptWriter

- DiffScripBackupWriter.ENCRYPTION_DIFF_SCRIPT_MAX_CHUNK_SIZE_BYTES is
now a constant rather than a flag.
- Additional tests were added for SingleStreamDiffScriptWriter.

Bug: 111386661
Test: atest RunBackupFrameworksServicesRoboTests
Change-Id: Ia3234bb8d665211e6fa91d6a92d190171b0d2dc1

3 files changed, 275 insertions, 0 deletions

diff --git a/services/robotests/src/com/android/server/backup/encryption/chunking/ByteRangeTest.java b/services/robotests/src/com/android/server/backup/encryption/chunking/ByteRangeTest.java
new file mode 100644
index 000000000000..8df08262c9fa
--- /dev/null
+++ b/services/robotests/src/com/android/server/backup/encryption/chunking/ByteRangeTest.java
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2018 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.server.backup.encryption.chunking;
+
+import static org.junit.Assert.assertEquals;
+import static org.testng.Assert.assertThrows;
+
+import android.platform.test.annotations.Presubmit;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Tests for {@link ByteRange}. */
+@RunWith(RobolectricTestRunner.class)
+@Presubmit
+public class ByteRangeTest {
+    @Test
+    public void getLength_includesEnd() throws Exception {
+        ByteRange byteRange = new ByteRange(5, 10);
+
+        int length = byteRange.getLength();
+
+        assertEquals(6, length);
+    }
+
+    @Test
+    public void constructor_rejectsNegativeStart() {
+        assertThrows(IllegalArgumentException.class, () -> new ByteRange(-1, 10));
+    }
+
+    @Test
+    public void constructor_rejectsEndBeforeStart() {
+        assertThrows(IllegalArgumentException.class, () -> new ByteRange(10, 9));
+    }
+
+    @Test
+    public void extend_withZeroLength_throwsException() {
+        ByteRange byteRange = new ByteRange(5, 10);
+
+        assertThrows(IllegalArgumentException.class, () -> byteRange.extend(0));
+    }
+}
diff --git a/services/robotests/src/com/android/server/backup/encryption/chunking/DiffScriptBackupWriterTest.java b/services/robotests/src/com/android/server/backup/encryption/chunking/DiffScriptBackupWriterTest.java
new file mode 100644
index 000000000000..2af6f2bee8ff
--- /dev/null
+++ b/services/robotests/src/com/android/server/backup/encryption/chunking/DiffScriptBackupWriterTest.java
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2018 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.server.backup.encryption.chunking;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.atLeastOnce;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import android.platform.test.annotations.Presubmit;
+
+import com.google.common.primitives.Bytes;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Captor;
+import org.mockito.Mock;
+import org.robolectric.RobolectricTestRunner;
+
+import java.io.IOException;
+
+/** Tests for {@link DiffScriptBackupWriter}. */
+@RunWith(RobolectricTestRunner.class)
+@Presubmit
+public class DiffScriptBackupWriterTest {
+    private static final byte[] TEST_BYTES = {1, 2, 3, 4, 5, 6, 7, 8, 9};
+
+    @Captor private ArgumentCaptor<Byte> mBytesCaptor;
+    @Mock private SingleStreamDiffScriptWriter mDiffScriptWriter;
+    private BackupWriter mBackupWriter;
+
+    @Before
+    public void setUp() {
+        mDiffScriptWriter = mock(SingleStreamDiffScriptWriter.class);
+        mBackupWriter = new DiffScriptBackupWriter(mDiffScriptWriter);
+        mBytesCaptor = ArgumentCaptor.forClass(Byte.class);
+    }
+
+    @Test
+    public void writeBytes_writesBytesToWriter() throws Exception {
+        mBackupWriter.writeBytes(TEST_BYTES);
+
+        verify(mDiffScriptWriter, atLeastOnce()).writeByte(mBytesCaptor.capture());
+        assertThat(mBytesCaptor.getAllValues())
+                .containsExactlyElementsIn(Bytes.asList(TEST_BYTES))
+                .inOrder();
+    }
+
+    @Test
+    public void writeChunk_writesChunkToWriter() throws Exception {
+        mBackupWriter.writeChunk(0, 10);
+
+        verify(mDiffScriptWriter).writeChunk(0, 10);
+    }
+
+    @Test
+    public void getBytesWritten_returnsTotalSum() throws Exception {
+        mBackupWriter.writeBytes(TEST_BYTES);
+        mBackupWriter.writeBytes(TEST_BYTES);
+        mBackupWriter.writeChunk(/*start=*/ 0, /*length=*/ 10);
+
+        long bytesWritten = mBackupWriter.getBytesWritten();
+
+        assertThat(bytesWritten).isEqualTo(2 * TEST_BYTES.length + 10);
+    }
+
+    @Test
+    public void flush_flushesWriter() throws IOException {
+        mBackupWriter.flush();
+
+        verify(mDiffScriptWriter).flush();
+    }
+}
diff --git a/services/robotests/src/com/android/server/backup/encryption/chunking/SingleStreamDiffScriptWriterTest.java b/services/robotests/src/com/android/server/backup/encryption/chunking/SingleStreamDiffScriptWriterTest.java
new file mode 100644
index 000000000000..73baf80a2c70
--- /dev/null
+++ b/services/robotests/src/com/android/server/backup/encryption/chunking/SingleStreamDiffScriptWriterTest.java
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2018 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.server.backup.encryption.chunking;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.testng.Assert.assertThrows;
+
+import android.platform.test.annotations.Presubmit;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Locale;
+
+/** Tests for {@link SingleStreamDiffScriptWriter}. */
+@RunWith(RobolectricTestRunner.class)
+@Presubmit
+public class SingleStreamDiffScriptWriterTest {
+    private static final int MAX_CHUNK_SIZE_IN_BYTES = 256;
+    /** By default this Locale does not use Arabic numbers for %d formatting. */
+    private static final Locale HINDI = new Locale("hi", "IN");
+
+    private Locale mDefaultLocale;
+    private ByteArrayOutputStream mOutputStream;
+    private SingleStreamDiffScriptWriter mDiffScriptWriter;
+
+    @Before
+    public void setUp() {
+        mDefaultLocale = Locale.getDefault();
+        mOutputStream = new ByteArrayOutputStream();
+        mDiffScriptWriter =
+                new SingleStreamDiffScriptWriter(mOutputStream, MAX_CHUNK_SIZE_IN_BYTES);
+    }
+
+    @After
+    public void tearDown() {
+        Locale.setDefault(mDefaultLocale);
+    }
+
+    @Test
+    public void writeChunk_withNegativeStart_throwsException() {
+        assertThrows(
+                IllegalArgumentException.class,
+                () -> mDiffScriptWriter.writeChunk(-1, 50));
+    }
+
+    @Test
+    public void writeChunk_withZeroLength_throwsException() {
+        assertThrows(
+                IllegalArgumentException.class,
+                () -> mDiffScriptWriter.writeChunk(0, 0));
+    }
+
+    @Test
+    public void writeChunk_withExistingBytesInBuffer_writesBufferFirst()
+            throws IOException {
+        String testString = "abcd";
+        writeStringAsBytesToWriter(testString, mDiffScriptWriter);
+
+        mDiffScriptWriter.writeChunk(0, 20);
+        mDiffScriptWriter.flush();
+
+        // Expected format: length of abcd, newline, abcd, newline, chunk start - chunk end
+        assertThat(mOutputStream.toString("UTF-8")).isEqualTo(
+                String.format("%d\n%s\n%d-%d\n", testString.length(), testString, 0, 19));
+    }
+
+    @Test
+    public void writeChunk_overlappingPreviousChunk_combinesChunks() throws IOException {
+        mDiffScriptWriter.writeChunk(3, 4);
+
+        mDiffScriptWriter.writeChunk(7, 5);
+        mDiffScriptWriter.flush();
+
+        assertThat(mOutputStream.toString("UTF-8")).isEqualTo(String.format("3-11\n"));
+    }
+
+    @Test
+    public void writeChunk_formatsByteIndexesUsingArabicNumbers() throws Exception {
+        Locale.setDefault(HINDI);
+
+        mDiffScriptWriter.writeChunk(0, 12345);
+        mDiffScriptWriter.flush();
+
+        assertThat(mOutputStream.toString("UTF-8")).isEqualTo("0-12344\n");
+    }
+
+    @Test
+    public void flush_flushesOutputStream() throws IOException {
+        ByteArrayOutputStream mockOutputStream = mock(ByteArrayOutputStream.class);
+        SingleStreamDiffScriptWriter diffScriptWriter =
+                new SingleStreamDiffScriptWriter(mockOutputStream, MAX_CHUNK_SIZE_IN_BYTES);
+
+        diffScriptWriter.flush();
+
+        verify(mockOutputStream).flush();
+    }
+
+    private void writeStringAsBytesToWriter(String string, SingleStreamDiffScriptWriter writer)
+            throws IOException {
+        byte[] bytes = string.getBytes("UTF-8");
+        for (int i = 0; i < bytes.length; i++) {
+            writer.writeByte(bytes[i]);
+        }
+    }
+}