Import FullRestoreToFileTask

Bug: 111386661
Test: make RunBackupEncryptionRoboTests
Change-Id: I4778357b9de9aab219c46b0f588012a8213e428c

2 files changed, 134 insertions, 0 deletions

diff --git a/packages/BackupEncryption/src/com/android/server/backup/encryption/FullRestoreDownloader.java b/packages/BackupEncryption/src/com/android/server/backup/encryption/FullRestoreDownloader.java
new file mode 100644
index 000000000000..afcca79a0027
--- /dev/null
+++ b/packages/BackupEncryption/src/com/android/server/backup/encryption/FullRestoreDownloader.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2019 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;
+
+import java.io.IOException;
+
+/** Interface for classes which will provide backup data */
+public abstract class FullRestoreDownloader {
+    /** Enum to provide information on why a download finished */
+    public enum FinishType {
+        UNKNOWN_FINISH(0),
+        // Finish the downloading and successfully write data to Android OS.
+        FINISHED(1),
+        // Download failed with any kind of exception.
+        TRANSFER_FAILURE(2),
+        // Download failed due to auth failure on the device.
+        AUTH_FAILURE(3),
+        // Aborted by Android Framework.
+        FRAMEWORK_ABORTED(4);
+
+        private int mValue;
+
+        FinishType(int value) {
+            mValue = value;
+        }
+    }
+
+    /** Get the next data chunk from the backing store */
+    public abstract int readNextChunk(byte[] buffer) throws IOException;
+
+    /** Called when we've finished restoring the data */
+    public abstract void finish(FinishType finishType);
+}
diff --git a/packages/BackupEncryption/src/com/android/server/backup/encryption/tasks/FullRestoreToFileTask.java b/packages/BackupEncryption/src/com/android/server/backup/encryption/tasks/FullRestoreToFileTask.java
new file mode 100644
index 000000000000..82f83f9b7494
--- /dev/null
+++ b/packages/BackupEncryption/src/com/android/server/backup/encryption/tasks/FullRestoreToFileTask.java
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2019 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.tasks;
+
+import static com.android.internal.util.Preconditions.checkArgument;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.server.backup.encryption.FullRestoreDownloader;
+import com.android.server.backup.encryption.FullRestoreDownloader.FinishType;
+
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+
+/**
+ * Reads a stream from a {@link FullRestoreDownloader} and writes it to a file for consumption by
+ * {@link BackupFileDecryptorTask}.
+ */
+public class FullRestoreToFileTask {
+    /**
+     * Maximum number of bytes which the framework can request from the full restore data stream in
+     * one call to {@link BackupTransport#getNextFullRestoreDataChunk}.
+     */
+    public static final int MAX_BYTES_FULL_RESTORE_CHUNK = 1024 * 32;
+
+    /** Returned when the end of a backup stream has been reached. */
+    private static final int END_OF_STREAM = -1;
+
+    private final FullRestoreDownloader mFullRestoreDownloader;
+    private final int mBufferSize;
+
+    /**
+     * Constructs a new instance which reads from the given package wrapper, using a buffer of size
+     * {@link #MAX_BYTES_FULL_RESTORE_CHUNK}.
+     */
+    public FullRestoreToFileTask(FullRestoreDownloader fullRestoreDownloader) {
+        this(fullRestoreDownloader, MAX_BYTES_FULL_RESTORE_CHUNK);
+    }
+
+    @VisibleForTesting
+    FullRestoreToFileTask(FullRestoreDownloader fullRestoreDownloader, int bufferSize) {
+        checkArgument(bufferSize > 0, "Buffer must have positive size");
+
+        this.mFullRestoreDownloader = fullRestoreDownloader;
+        this.mBufferSize = bufferSize;
+    }
+
+    /**
+     * Downloads the backup file from the server and writes it to the given file.
+     *
+     * <p>At the end of the download (success or failure), closes the connection and sends a
+     * Clearcut log.
+     */
+    public void restoreToFile(File targetFile) throws IOException {
+        try (BufferedOutputStream outputStream =
+                new BufferedOutputStream(new FileOutputStream(targetFile))) {
+            byte[] buffer = new byte[mBufferSize];
+            int bytesRead = mFullRestoreDownloader.readNextChunk(buffer);
+            while (bytesRead != END_OF_STREAM) {
+                outputStream.write(buffer, /* off=*/ 0, bytesRead);
+                bytesRead = mFullRestoreDownloader.readNextChunk(buffer);
+            }
+
+            outputStream.flush();
+
+            mFullRestoreDownloader.finish(FinishType.FINISHED);
+        } catch (IOException e) {
+            mFullRestoreDownloader.finish(FinishType.TRANSFER_FAILURE);
+            throw e;
+        }
+    }
+}