src/main/java/com/google/devtools/build/lib/skyframe/serialization/testutils/TestUtils.java

// Copyright 2017 The Bazel Authors. 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.devtools.build.lib.skyframe.serialization.testutils;

import static com.google.common.truth.Truth.assertThat;

import com.google.common.collect.ImmutableMap;
import com.google.devtools.build.lib.skyframe.serialization.AutoRegistry;
import com.google.devtools.build.lib.skyframe.serialization.CodecRegisterer;
import com.google.devtools.build.lib.skyframe.serialization.DeserializationContext;
import com.google.devtools.build.lib.skyframe.serialization.Memoizer.Deserializer;
import com.google.devtools.build.lib.skyframe.serialization.Memoizer.MemoizingCodec;
import com.google.devtools.build.lib.skyframe.serialization.Memoizer.Serializer;
import com.google.devtools.build.lib.skyframe.serialization.ObjectCodec;
import com.google.devtools.build.lib.skyframe.serialization.ObjectCodecRegistry;
import com.google.devtools.build.lib.skyframe.serialization.SerializationContext;
import com.google.devtools.build.lib.skyframe.serialization.SerializationException;
import com.google.devtools.build.lib.skyframe.serialization.strings.StringCodecs;
import com.google.devtools.build.lib.syntax.Environment.GlobalFrame;
import com.google.devtools.build.lib.syntax.Mutability;
import com.google.protobuf.ByteString;
import com.google.protobuf.CodedInputStream;
import com.google.protobuf.CodedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.annotation.Nullable;

/** Helpers for serialization tests. */
public class TestUtils {

  private TestUtils() {}

  /** Serialize a value to a new byte array. */
  public static <T> byte[] toBytes(SerializationContext context, ObjectCodec<T> codec, T value)
      throws IOException, SerializationException {
    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    CodedOutputStream codedOut = CodedOutputStream.newInstance(bytes);
    codec.serialize(context, value, codedOut);
    codedOut.flush();
    return bytes.toByteArray();
  }

  public static <T> ByteString toBytes(T value, ImmutableMap<Class<?>, Object> dependencies)
      throws IOException, SerializationException {
    return toBytes(value, new SerializationContext(dependencies));
  }

  private static <T> ByteString toBytes(T value, SerializationContext serializationContext)
      throws IOException, SerializationException {
    ByteString.Output output = ByteString.newOutput();
    CodedOutputStream codedOut = CodedOutputStream.newInstance(output);
    serializationContext.serialize(value, codedOut);
    codedOut.flush();
    return output.toByteString();
  }

  /** Deserialize a value from a byte array. */
  public static <T> T fromBytes(DeserializationContext context, ObjectCodec<T> codec, byte[] bytes)
      throws SerializationException, IOException {
    return codec.deserialize(context, CodedInputStream.newInstance(bytes));
  }

  public static <T> T roundTrip(T value, ImmutableMap<Class<?>, Object> dependencies)
      throws IOException, SerializationException {
    ObjectCodecRegistry.Builder builder = AutoRegistry.get().getBuilder();
    for (Object constant : dependencies.values()) {
      builder.addConstant(constant);
    }
    ObjectCodecRegistry registry = builder.build();
    return new DeserializationContext(registry, dependencies)
        .deserialize(
            toBytes(value, new SerializationContext(registry, dependencies)).newCodedInput());
  }

  /**
   * Asserts that two {@link GlobalFrame}s have the same structure. Needed because
   * {@link GlobalFrame} doesn't override {@link Object#equals}.
   */
  public static void assertGlobalFramesEqual(GlobalFrame frame1, GlobalFrame frame2) {
    assertThat(frame1.mutability().getAnnotation())
        .isEqualTo(frame2.mutability().getAnnotation());
    assertThat(frame1.getLabel()).isEqualTo(frame2.getLabel());
    assertThat(frame1.getTransitiveBindings())
        .containsExactlyEntriesIn(frame2.getTransitiveBindings()).inOrder();
    if (frame1.getParent() == null || frame2.getParent() == null) {
      assertThat(frame1.getParent()).isNull();
      assertThat(frame2.getParent()).isNull();
    } else {
      assertGlobalFramesEqual(frame1.getParent(), frame2.getParent());
    }
  }

  public static ByteString toBytesMemoized(Object original, ObjectCodecRegistry registry)
      throws IOException, SerializationException {
    ByteString.Output output = ByteString.newOutput();
    CodedOutputStream codedOut = CodedOutputStream.newInstance(output);
    new Serializer()
        .serialize(new SerializationContext(registry, ImmutableMap.of()), original, codedOut);
    codedOut.flush();
    return output.toByteString();
  }

  public static Object fromBytesMemoized(ByteString bytes, ObjectCodecRegistry registry)
      throws IOException, SerializationException {
    return new Deserializer()
        .deserialize(
            new DeserializationContext(registry, ImmutableMap.of()), bytes.newCodedInput());
  }

  public static <T> T roundTripMemoized(T original, ObjectCodecRegistry registry)
      throws IOException, SerializationException {
    return roundTripMemoized(original, /*mutability=*/ null, registry);
  }

  @SuppressWarnings("unchecked") // Cast to T in return.
  public static <T> T roundTripMemoized(
      T original, @Nullable Mutability mutability, ObjectCodecRegistry registry)
      throws IOException, SerializationException {
    return (T)
        (mutability == null ? new Deserializer() : new Deserializer(mutability))
            .deserialize(
                new DeserializationContext(registry, ImmutableMap.of()),
                toBytesMemoized(original, registry).newCodedInput());
  }

  public static <T> T roundTripMemoized(T original, MemoizingCodec<?>... codecs)
      throws IOException, SerializationException {
    return roundTripMemoized(original, getBuilderWithMemoized(codecs).build());
  }

  public static <T> T roundTripMemoized(
      T original, @Nullable Mutability mutability, MemoizingCodec<?>... codecs)
      throws IOException, SerializationException {
    return roundTripMemoized(original, mutability, getBuilderWithMemoized(codecs).build());
  }

  public static ObjectCodecRegistry.Builder getBuilderWithMemoized(MemoizingCodec<?>... codecs) {
    ObjectCodecRegistry.Builder builder = AutoRegistry.get().getBuilder();
    for (MemoizingCodec<?> codec : codecs) {
      builder.addMemoizing(codec);
    }
    return builder;
  }

  /**
   * Fake string codec that replaces all input and output string values with the constant "dummy".
   */
  public static class ConstantStringCodec implements ObjectCodec<String> {

    private static final ObjectCodec<String> stringCodec = StringCodecs.simple();

    @Override
    public Class<String> getEncodedClass() {
      return String.class;
    }

    @Override
    public void serialize(SerializationContext context, String value, CodedOutputStream codedOut)
        throws SerializationException, IOException {
      stringCodec.serialize(context, "dummy", codedOut);
    }

    @Override
    public String deserialize(DeserializationContext context, CodedInputStream codedIn)
        throws SerializationException, IOException {
      stringCodec.deserialize(context, codedIn);
      return "dummy";
    }

    /** Disables auto-registration of ConstantStringCodec. */
    private static class ConstantStringCodecRegisterer
        implements CodecRegisterer<ConstantStringCodec> {}
  }
}