| // Copyright 2022 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; |
| |
| import static com.google.common.truth.Truth.assertThat; |
| |
| import com.google.devtools.build.lib.skyframe.serialization.testutils.TestUtils; |
| import java.io.IOException; |
| import javax.annotation.Nullable; |
| import org.junit.Test; |
| import org.junit.runner.RunWith; |
| import org.junit.runners.JUnit4; |
| |
| /** Tests memo-based encoding and decoding, especially for cyclic data structures. */ |
| @RunWith(JUnit4.class) |
| public class MemoizerTest { |
| |
| // These classes are used to model a potentially cyclic data structure with both mutable and |
| // immutable components. |
| |
| private interface DummyLinkedList { |
| |
| String getValue(); |
| |
| @Nullable |
| DummyLinkedList getNext(); |
| } |
| |
| private static class MutableDummy implements DummyLinkedList { |
| |
| private final String value; |
| |
| @Nullable private DummyLinkedList next; |
| |
| MutableDummy(String value, @Nullable DummyLinkedList next) { |
| this.value = value; |
| this.next = next; |
| } |
| |
| @Override |
| public String getValue() { |
| return value; |
| } |
| |
| @Override |
| @Nullable |
| public DummyLinkedList getNext() { |
| return next; |
| } |
| |
| void setNext(@Nullable DummyLinkedList next) { |
| this.next = next; |
| } |
| } |
| |
| private static class ImmutableDummy implements DummyLinkedList { |
| |
| private final String value; |
| |
| @Nullable private final DummyLinkedList next; |
| |
| ImmutableDummy(String value, @Nullable DummyLinkedList next) { |
| this.value = value; |
| this.next = next; |
| } |
| |
| @Override |
| public String getValue() { |
| return value; |
| } |
| |
| @Override |
| @Nullable |
| public DummyLinkedList getNext() { |
| return next; |
| } |
| } |
| |
| @Test |
| public void chainOfMutables() throws IOException, SerializationException { |
| DummyLinkedList c = new MutableDummy("C", null); |
| DummyLinkedList b = new MutableDummy("B", c); |
| DummyLinkedList a = new MutableDummy("A", b); |
| assertABC(TestUtils.roundTripMemoized(a)); |
| } |
| |
| @Test |
| public void chainOfMixed() throws IOException, SerializationException { |
| DummyLinkedList c = new MutableDummy("C", null); |
| DummyLinkedList b = new ImmutableDummy("B", c); |
| DummyLinkedList a = new MutableDummy("A", b); |
| assertABC(TestUtils.roundTripMemoized(a)); |
| } |
| |
| @Test |
| public void cycleOfMutables() throws IOException, SerializationException { |
| MutableDummy b = new MutableDummy("B", null); |
| DummyLinkedList a = new MutableDummy("A", b); |
| b.setNext(a); |
| assertABcycle(TestUtils.roundTripMemoized(a)); |
| } |
| |
| @Test |
| public void cycleOfMixedWithMutableRoot() throws IOException, SerializationException { |
| MutableDummy a = new MutableDummy("A", null); |
| DummyLinkedList b = new ImmutableDummy("B", a); |
| a.setNext(b); |
| assertABcycle(TestUtils.roundTripMemoized(a)); |
| } |
| |
| @Test |
| public void cycleOfMixedWithImmutableRoot() throws IOException, SerializationException { |
| MutableDummy b = new MutableDummy("B", null); |
| DummyLinkedList a = new ImmutableDummy("A", b); |
| b.setNext(a); |
| assertABcycle(TestUtils.roundTripMemoized(a)); |
| } |
| |
| /** Asserts that {@code value} has the linked list structure {@code A -> B -> C}. */ |
| private static void assertABC(DummyLinkedList value) { |
| assertThat(value.getValue()).isEqualTo("A"); |
| assertThat(value.getNext()).isNotNull(); |
| assertThat(value.getNext().getValue()).isEqualTo("B"); |
| assertThat(value.getNext().getNext()).isNotNull(); |
| assertThat(value.getNext().getNext().getValue()).isEqualTo("C"); |
| assertThat(value.getNext().getNext().getNext()).isNull(); |
| } |
| |
| /** Asserts that {@code value} has the cyclic linked list structure {@code A -> B -> A...}. */ |
| private static void assertABcycle(DummyLinkedList value) { |
| assertThat(value.getValue()).isEqualTo("A"); |
| assertThat(value.getNext()).isNotNull(); |
| assertThat(value.getNext().getValue()).isEqualTo("B"); |
| assertThat(value.getNext().getNext()).isNotNull(); |
| // Check instance identity to ensure we reproduced the object graph without creating duplicates. |
| assertThat(value.getNext().getNext()).isSameInstanceAs(value); |
| } |
| } |