Import code from internal repository to git

java/com/google/domain/registry/backup/BackupUtils.java

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+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// 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.google.domain.registry.backup;
+
+import static com.google.domain.registry.model.ofy.ObjectifyService.ofy;
+
+import com.google.appengine.api.datastore.EntityTranslator;
+import com.google.common.collect.AbstractIterator;
+import com.google.common.collect.ImmutableList;
+import com.google.domain.registry.model.ImmutableObject;
+import com.google.storage.onestore.v3.OnestoreEntity.EntityProto;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Iterator;
+
+/** Utilities for working with backups. */
+public class BackupUtils {
+
+  /** Keys for user metadata fields on commit log files in GCS. */
+  public static final class GcsMetadataKeys {
+
+    private GcsMetadataKeys() {}
+
+    public static final String NUM_TRANSACTIONS = "num_transactions";
+    public static final String LOWER_BOUND_CHECKPOINT = "lower_bound_checkpoint";
+    public static final String UPPER_BOUND_CHECKPOINT = "upper_bound_checkpoint";
+  }
+
+  /**
+   * Converts the given {@link ImmutableObject} to a raw datastore entity and write it to an 
+   * {@link OutputStream} in delimited protocol buffer format.
+   */
+  static void serializeEntity(ImmutableObject entity, OutputStream stream) throws IOException {
+    EntityTranslator.convertToPb(ofy().save().toEntity(entity)).writeDelimitedTo(stream);
+  }
+
+  /**
+   * Return an iterator of {@link ImmutableObject} instances deserialized from the given stream.
+   *
+   * <p>This parses out delimited protocol buffers for raw datastore entities and then Ofy-loads
+   * those as {@link ImmutableObject}.
+   *
+   * <p>The iterator reads from the stream on demand, and as such will fail if the stream is closed.
+   */
+  public static Iterator<ImmutableObject> createDeserializingIterator(final InputStream input) {
+    return new AbstractIterator<ImmutableObject>() {
+      @Override
+      protected ImmutableObject computeNext() {
+        EntityProto proto = new EntityProto();
+        if (proto.parseDelimitedFrom(input)) {  // False means end of stream; other errors throw.
+          return ofy().load().<ImmutableObject>fromEntity(EntityTranslator.createFromPb(proto));
+        }
+        return endOfData();
+      }};
+  }
+
+  public static ImmutableList<ImmutableObject> deserializeEntities(byte[] bytes) {
+    return ImmutableList.copyOf(createDeserializingIterator(new ByteArrayInputStream(bytes)));
+  }
+}