| // Copyright 2018 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 com.google.common.collect.ImmutableMap; |
| import com.google.common.collect.ImmutableSortedMap; |
| import com.google.common.collect.Ordering; |
| import com.google.protobuf.CodedInputStream; |
| import com.google.protobuf.CodedOutputStream; |
| import java.io.IOException; |
| import java.util.Comparator; |
| import java.util.Map; |
| |
| /** |
| * Encodes an {@link ImmutableMap}, which may be an {@link ImmutableSortedMap}. The iteration order |
| * of the deserialized map is the same as the original map's. |
| * |
| * <p>We handle both {@link ImmutableMap} and {@link ImmutableSortedMap} here because we cannot |
| * handle {@link ImmutableSortedMap} with any ordering other than the default, and so we degrade to |
| * ImmutableMap in that case, hoping that the caller does not notice. Since the ordering is |
| * preserved, the caller should not be sensitive to this change unless the caller's field is |
| * declared to be an {@link ImmutableSortedMap}, in which case we will crash at runtime. |
| * |
| * <p>Any {@link SerializationException} or {@link IOException} that arises while serializing or |
| * deserializing a map entry's value (not its key) will be wrapped in a new {@link |
| * SerializationException} using {@link SerializationException#propagate}. (Note that this preserves |
| * the type of {@link SerializationException.NoCodecException} exceptions.) The message will include |
| * the {@code toString()} of the entry's key. For errors that occur while serializing, it will also |
| * include the class name of the entry's value. Errors that occur while serializing an entry key are |
| * not affected. |
| * |
| * <p>Because of the ambiguity around the key type (Comparable in the case of {@link |
| * ImmutableSortedMap}, arbitrary otherwise, we avoid specifying the key type as a parameter. |
| */ |
| class ImmutableMapCodec<V> implements ObjectCodec<ImmutableMap<?, V>> { |
| @SuppressWarnings("unchecked") |
| @Override |
| public Class<ImmutableMap<?, V>> getEncodedClass() { |
| // Because Java disallows converting from Class<ImmutableMap> to Class<ImmutableMap<?, ?>> |
| // directly. |
| return (Class<ImmutableMap<?, V>>) ((Class<?>) ImmutableMap.class); |
| } |
| |
| @Override |
| public void serialize( |
| SerializationContext context, ImmutableMap<?, V> map, CodedOutputStream codedOut) |
| throws SerializationException, IOException { |
| codedOut.writeInt32NoTag(map.size()); |
| boolean serializeAsSortedMap = false; |
| if (map instanceof ImmutableSortedMap) { |
| Comparator<?> comparator = ((ImmutableSortedMap<?, ?>) map).comparator(); |
| // In practice the comparator seems to always be Ordering.natural(), but be flexible. |
| serializeAsSortedMap = |
| comparator.equals(Ordering.natural()) || comparator.equals(Comparator.naturalOrder()); |
| } |
| codedOut.writeBoolNoTag(serializeAsSortedMap); |
| serializeEntries(context, map.entrySet(), codedOut); |
| } |
| |
| static <K, V> void serializeEntries( |
| SerializationContext context, |
| Iterable<? extends Map.Entry<K, V>> entrySet, |
| CodedOutputStream codedOut) |
| throws IOException, SerializationException { |
| for (Map.Entry<?, ?> entry : entrySet) { |
| context.serialize(entry.getKey(), codedOut); |
| try { |
| context.serialize(entry.getValue(), codedOut); |
| } catch (SerializationException | IOException e) { |
| throw SerializationException.propagate( |
| String.format( |
| "Exception while serializing value of type %s for key '%s'", |
| entry.getValue().getClass().getName(), entry.getKey()), |
| e); |
| } |
| } |
| } |
| |
| @Override |
| public ImmutableMap<?, V> deserialize(DeserializationContext context, CodedInputStream codedIn) |
| throws SerializationException, IOException { |
| int length = codedIn.readInt32(); |
| if (length < 0) { |
| throw new SerializationException("Expected non-negative length: " + length); |
| } |
| ImmutableMap.Builder<?, V> builder; |
| if (codedIn.readBool()) { |
| builder = deserializeEntries(ImmutableSortedMap.naturalOrder(), length, context, codedIn); |
| } else { |
| builder = |
| deserializeEntries( |
| ImmutableMap.builderWithExpectedSize(length), length, context, codedIn); |
| } |
| try { |
| return builder.build(); |
| } catch (IllegalArgumentException e) { |
| throw new SerializationException( |
| "Duplicate keys during ImmutableMapCodec deserialization", e); |
| } |
| } |
| |
| static <K, V, M extends ImmutableMap.Builder<K, V>> M deserializeEntries( |
| M builder, int length, DeserializationContext context, CodedInputStream codedIn) |
| throws IOException, SerializationException { |
| for (int i = 0; i < length; i++) { |
| K key = context.deserialize(codedIn); |
| V value; |
| try { |
| value = context.deserialize(codedIn); |
| } catch (SerializationException | IOException e) { |
| throw SerializationException.propagate( |
| String.format("Exception while deserializing value for key '%s'", key), e); |
| } |
| builder.put(key, value); |
| } |
| return builder; |
| } |
| } |