Line data    Source code

       1             : // Copyright (C) 2018 The Android Open Source Project
       2             : //
       3             : // Licensed under the Apache License, Version 2.0 (the "License");
       4             : // you may not use this file except in compliance with the License.
       5             : // You may obtain a copy of the License at
       6             : //
       7             : // http://www.apache.org/licenses/LICENSE-2.0
       8             : //
       9             : // Unless required by applicable law or agreed to in writing, software
      10             : // distributed under the License is distributed on an "AS IS" BASIS,
      11             : // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             : // See the License for the specific language governing permissions and
      13             : // limitations under the License.
      14             : 
      15             : package com.google.gerrit.proto;
      16             : 
      17             : import com.google.protobuf.ByteString;
      18             : import com.google.protobuf.CodedOutputStream;
      19             : import com.google.protobuf.MessageLite;
      20             : import com.google.protobuf.Parser;
      21             : import java.io.IOException;
      22             : 
      23             : /** Static utilities for dealing with protobuf-based objects. */
      24             : public class Protos {
      25             :   /**
      26             :    * Serializes a proto to a byte array.
      27             :    *
      28             :    * <p>Guarantees deterministic serialization. No matter whether the use case cares about
      29             :    * determinism or not, always use this method in preference to {@link MessageLite#toByteArray()},
      30             :    * which is not guaranteed deterministic.
      31             :    *
      32             :    * @param message the proto message to serialize.
      33             :    * @return a byte array with the message contents.
      34             :    */
      35             :   public static byte[] toByteArray(MessageLite message) {
      36         115 :     byte[] bytes = new byte[message.getSerializedSize()];
      37         115 :     CodedOutputStream cout = CodedOutputStream.newInstance(bytes);
      38         115 :     cout.useDeterministicSerialization();
      39             :     try {
      40         115 :       message.writeTo(cout);
      41         115 :       cout.checkNoSpaceLeft();
      42         115 :       return bytes;
      43           0 :     } catch (IOException e) {
      44           0 :       throw new IllegalStateException("exception writing to byte array", e);
      45             :     }
      46             :   }
      47             : 
      48             :   /**
      49             :    * Serializes a proto to a {@code ByteString}.
      50             :    *
      51             :    * <p>Guarantees deterministic serialization. No matter whether the use case cares about
      52             :    * determinism or not, always use this method in preference to {@link MessageLite#toByteString()},
      53             :    * which is not guaranteed deterministic.
      54             :    *
      55             :    * @param message the proto message to serialize
      56             :    * @return a {@code ByteString} with the message contents
      57             :    */
      58             :   public static ByteString toByteString(MessageLite message) {
      59           2 :     try (ByteString.Output bout = ByteString.newOutput(message.getSerializedSize())) {
      60           2 :       CodedOutputStream outputStream = CodedOutputStream.newInstance(bout);
      61           2 :       outputStream.useDeterministicSerialization();
      62           2 :       message.writeTo(outputStream);
      63           2 :       outputStream.flush();
      64           2 :       return bout.toByteString();
      65           0 :     } catch (IOException e) {
      66           0 :       throw new IllegalStateException("exception writing to ByteString", e);
      67             :     }
      68             :   }
      69             : 
      70             :   /**
      71             :    * Parses a byte array to a protobuf message.
      72             :    *
      73             :    * @param parser parser for the proto type.
      74             :    * @param in byte array with the message contents.
      75             :    * @return parsed proto.
      76             :    */
      77             :   public static <M extends MessageLite> M parseUnchecked(Parser<M> parser, byte[] in) {
      78             :     try {
      79          22 :       return parser.parseFrom(in);
      80           1 :     } catch (IOException e) {
      81           1 :       throw new IllegalArgumentException("exception parsing byte array to proto", e);
      82             :     }
      83             :   }
      84             : 
      85             :   /**
      86             :    * Parses a specific segment of a byte array to a protobuf message.
      87             :    *
      88             :    * @param parser parser for the proto type
      89             :    * @param in byte array with the message contents
      90             :    * @param offset offset in the byte array to start reading from
      91             :    * @param length amount of read bytes
      92             :    * @return parsed proto
      93             :    */
      94             :   public static <M extends MessageLite> M parseUnchecked(
      95             :       Parser<M> parser, byte[] in, int offset, int length) {
      96             :     try {
      97         101 :       return parser.parseFrom(in, offset, length);
      98           1 :     } catch (IOException e) {
      99           1 :       throw new IllegalArgumentException("exception parsing byte array to proto", e);
     100             :     }
     101             :   }
     102             : 
     103             :   /**
     104             :    * Parses a {@code ByteString} to a protobuf message.
     105             :    *
     106             :    * @param parser parser for the proto type
     107             :    * @param byteString {@code ByteString} with the message contents
     108             :    * @return parsed proto
     109             :    */
     110             :   public static <M extends MessageLite> M parseUnchecked(Parser<M> parser, ByteString byteString) {
     111             :     try {
     112           1 :       return parser.parseFrom(byteString);
     113           1 :     } catch (IOException e) {
     114           1 :       throw new IllegalArgumentException("exception parsing ByteString to proto", e);
     115             :     }
     116             :   }
     117             : 
     118             :   private Protos() {}
     119             : }