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Diffstat (limited to 'csharp/src/Google.Protobuf/Collections/MapField.cs')
| -rw-r--r-- | csharp/src/Google.Protobuf/Collections/MapField.cs | 760 |
1 files changed, 760 insertions, 0 deletions
diff --git a/csharp/src/Google.Protobuf/Collections/MapField.cs b/csharp/src/Google.Protobuf/Collections/MapField.cs new file mode 100644 index 00000000..537ce261 --- /dev/null +++ b/csharp/src/Google.Protobuf/Collections/MapField.cs @@ -0,0 +1,760 @@ +#region Copyright notice and license +// Protocol Buffers - Google's data interchange format +// Copyright 2015 Google Inc. All rights reserved. +// https://developers.google.com/protocol-buffers/ +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +#endregion + +using Google.Protobuf.Compatibility; +using Google.Protobuf.Reflection; +using System; +using System.Collections; +using System.Collections.Generic; +using System.IO; +using System.Linq; + +namespace Google.Protobuf.Collections +{ + /// <summary> + /// Representation of a map field in a Protocol Buffer message. + /// </summary> + /// <typeparam name="TKey">Key type in the map. Must be a type supported by Protocol Buffer map keys.</typeparam> + /// <typeparam name="TValue">Value type in the map. Must be a type supported by Protocol Buffers.</typeparam> + /// <remarks> + /// <para> + /// For string keys, the equality comparison is provided by <see cref="StringComparer.Ordinal" />. + /// </para> + /// <para> + /// Null values are not permitted in the map, either for wrapper types or regular messages. + /// If a map is deserialized from a data stream and the value is missing from an entry, a default value + /// is created instead. For primitive types, that is the regular default value (0, the empty string and so + /// on); for message types, an empty instance of the message is created, as if the map entry contained a 0-length + /// encoded value for the field. + /// </para> + /// <para> + /// This implementation does not generally prohibit the use of key/value types which are not + /// supported by Protocol Buffers (e.g. using a key type of <code>byte</code>) but nor does it guarantee + /// that all operations will work in such cases. + /// </para> + /// <para> + /// The order in which entries are returned when iterating over this object is undefined, and may change + /// in future versions. + /// </para> + /// </remarks> + public sealed class MapField<TKey, TValue> : IDeepCloneable<MapField<TKey, TValue>>, IDictionary<TKey, TValue>, IEquatable<MapField<TKey, TValue>>, IDictionary + { + // TODO: Don't create the map/list until we have an entry. (Assume many maps will be empty.) + private readonly Dictionary<TKey, LinkedListNode<KeyValuePair<TKey, TValue>>> map = + new Dictionary<TKey, LinkedListNode<KeyValuePair<TKey, TValue>>>(); + private readonly LinkedList<KeyValuePair<TKey, TValue>> list = new LinkedList<KeyValuePair<TKey, TValue>>(); + + /// <summary> + /// Creates a deep clone of this object. + /// </summary> + /// <returns> + /// A deep clone of this object. + /// </returns> + public MapField<TKey, TValue> Clone() + { + var clone = new MapField<TKey, TValue>(); + // Keys are never cloneable. Values might be. + if (typeof(IDeepCloneable<TValue>).IsAssignableFrom(typeof(TValue))) + { + foreach (var pair in list) + { + clone.Add(pair.Key, ((IDeepCloneable<TValue>)pair.Value).Clone()); + } + } + else + { + // Nothing is cloneable, so we don't need to worry. + clone.Add(this); + } + return clone; + } + + /// <summary> + /// Adds the specified key/value pair to the map. + /// </summary> + /// <remarks> + /// This operation fails if the key already exists in the map. To replace an existing entry, use the indexer. + /// </remarks> + /// <param name="key">The key to add</param> + /// <param name="value">The value to add.</param> + /// <exception cref="System.ArgumentException">The given key already exists in map.</exception> + public void Add(TKey key, TValue value) + { + // Validation of arguments happens in ContainsKey and the indexer + if (ContainsKey(key)) + { + throw new ArgumentException("Key already exists in map", nameof(key)); + } + this[key] = value; + } + + /// <summary> + /// Determines whether the specified key is present in the map. + /// </summary> + /// <param name="key">The key to check.</param> + /// <returns><c>true</c> if the map contains the given key; <c>false</c> otherwise.</returns> + public bool ContainsKey(TKey key) + { + ProtoPreconditions.CheckNotNullUnconstrained(key, nameof(key)); + return map.ContainsKey(key); + } + + private bool ContainsValue(TValue value) + { + var comparer = EqualityComparer<TValue>.Default; + return list.Any(pair => comparer.Equals(pair.Value, value)); + } + + /// <summary> + /// Removes the entry identified by the given key from the map. + /// </summary> + /// <param name="key">The key indicating the entry to remove from the map.</param> + /// <returns><c>true</c> if the map contained the given key before the entry was removed; <c>false</c> otherwise.</returns> + public bool Remove(TKey key) + { + ProtoPreconditions.CheckNotNullUnconstrained(key, nameof(key)); + LinkedListNode<KeyValuePair<TKey, TValue>> node; + if (map.TryGetValue(key, out node)) + { + map.Remove(key); + node.List.Remove(node); + return true; + } + else + { + return false; + } + } + + /// <summary> + /// Gets the value associated with the specified key. + /// </summary> + /// <param name="key">The key whose value to get.</param> + /// <param name="value">When this method returns, the value associated with the specified key, if the key is found; + /// otherwise, the default value for the type of the <paramref name="value"/> parameter. + /// This parameter is passed uninitialized.</param> + /// <returns><c>true</c> if the map contains an element with the specified key; otherwise, <c>false</c>.</returns> + public bool TryGetValue(TKey key, out TValue value) + { + LinkedListNode<KeyValuePair<TKey, TValue>> node; + if (map.TryGetValue(key, out node)) + { + value = node.Value.Value; + return true; + } + else + { + value = default(TValue); + return false; + } + } + + /// <summary> + /// Gets or sets the value associated with the specified key. + /// </summary> + /// <param name="key">The key of the value to get or set.</param> + /// <exception cref="KeyNotFoundException">The property is retrieved and key does not exist in the collection.</exception> + /// <returns>The value associated with the specified key. If the specified key is not found, + /// a get operation throws a <see cref="KeyNotFoundException"/>, and a set operation creates a new element with the specified key.</returns> + public TValue this[TKey key] + { + get + { + ProtoPreconditions.CheckNotNullUnconstrained(key, nameof(key)); + TValue value; + if (TryGetValue(key, out value)) + { + return value; + } + throw new KeyNotFoundException(); + } + set + { + ProtoPreconditions.CheckNotNullUnconstrained(key, nameof(key)); + // value == null check here is redundant, but avoids boxing. + if (value == null) + { + ProtoPreconditions.CheckNotNullUnconstrained(value, nameof(value)); + } + LinkedListNode<KeyValuePair<TKey, TValue>> node; + var pair = new KeyValuePair<TKey, TValue>(key, value); + if (map.TryGetValue(key, out node)) + { + node.Value = pair; + } + else + { + node = list.AddLast(pair); + map[key] = node; + } + } + } + + /// <summary> + /// Gets a collection containing the keys in the map. + /// </summary> + public ICollection<TKey> Keys { get { return new MapView<TKey>(this, pair => pair.Key, ContainsKey); } } + + /// <summary> + /// Gets a collection containing the values in the map. + /// </summary> + public ICollection<TValue> Values { get { return new MapView<TValue>(this, pair => pair.Value, ContainsValue); } } + + /// <summary> + /// Adds the specified entries to the map. The keys and values are not automatically cloned. + /// </summary> + /// <param name="entries">The entries to add to the map.</param> + public void Add(IDictionary<TKey, TValue> entries) + { + ProtoPreconditions.CheckNotNull(entries, nameof(entries)); + foreach (var pair in entries) + { + Add(pair.Key, pair.Value); + } + } + + /// <summary> + /// Returns an enumerator that iterates through the collection. + /// </summary> + /// <returns> + /// An enumerator that can be used to iterate through the collection. + /// </returns> + public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator() + { + return list.GetEnumerator(); + } + + /// <summary> + /// Returns an enumerator that iterates through a collection. + /// </summary> + /// <returns> + /// An <see cref="T:System.Collections.IEnumerator" /> object that can be used to iterate through the collection. + /// </returns> + IEnumerator IEnumerable.GetEnumerator() + { + return GetEnumerator(); + } + + /// <summary> + /// Adds the specified item to the map. + /// </summary> + /// <param name="item">The item to add to the map.</param> + void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> item) + { + Add(item.Key, item.Value); + } + + /// <summary> + /// Removes all items from the map. + /// </summary> + public void Clear() + { + list.Clear(); + map.Clear(); + } + + /// <summary> + /// Determines whether map contains an entry equivalent to the given key/value pair. + /// </summary> + /// <param name="item">The key/value pair to find.</param> + /// <returns></returns> + bool ICollection<KeyValuePair<TKey, TValue>>.Contains(KeyValuePair<TKey, TValue> item) + { + TValue value; + return TryGetValue(item.Key, out value) + && EqualityComparer<TValue>.Default.Equals(item.Value, value); + } + + /// <summary> + /// Copies the key/value pairs in this map to an array. + /// </summary> + /// <param name="array">The array to copy the entries into.</param> + /// <param name="arrayIndex">The index of the array at which to start copying values.</param> + void ICollection<KeyValuePair<TKey, TValue>>.CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex) + { + list.CopyTo(array, arrayIndex); + } + + /// <summary> + /// Removes the specified key/value pair from the map. + /// </summary> + /// <remarks>Both the key and the value must be found for the entry to be removed.</remarks> + /// <param name="item">The key/value pair to remove.</param> + /// <returns><c>true</c> if the key/value pair was found and removed; <c>false</c> otherwise.</returns> + bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> item) + { + if (item.Key == null) + { + throw new ArgumentException("Key is null", nameof(item)); + } + LinkedListNode<KeyValuePair<TKey, TValue>> node; + if (map.TryGetValue(item.Key, out node) && + EqualityComparer<TValue>.Default.Equals(item.Value, node.Value.Value)) + { + map.Remove(item.Key); + node.List.Remove(node); + return true; + } + else + { + return false; + } + } + + /// <summary> + /// Gets the number of elements contained in the map. + /// </summary> + public int Count { get { return list.Count; } } + + /// <summary> + /// Gets a value indicating whether the map is read-only. + /// </summary> + public bool IsReadOnly { get { return false; } } + + /// <summary> + /// Determines whether the specified <see cref="System.Object" />, is equal to this instance. + /// </summary> + /// <param name="other">The <see cref="System.Object" /> to compare with this instance.</param> + /// <returns> + /// <c>true</c> if the specified <see cref="System.Object" /> is equal to this instance; otherwise, <c>false</c>. + /// </returns> + public override bool Equals(object other) + { + return Equals(other as MapField<TKey, TValue>); + } + + /// <summary> + /// Returns a hash code for this instance. + /// </summary> + /// <returns> + /// A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table. + /// </returns> + public override int GetHashCode() + { + var valueComparer = EqualityComparer<TValue>.Default; + int hash = 0; + foreach (var pair in list) + { + hash ^= pair.Key.GetHashCode() * 31 + valueComparer.GetHashCode(pair.Value); + } + return hash; + } + + /// <summary> + /// Compares this map with another for equality. + /// </summary> + /// <remarks> + /// The order of the key/value pairs in the maps is not deemed significant in this comparison. + /// </remarks> + /// <param name="other">The map to compare this with.</param> + /// <returns><c>true</c> if <paramref name="other"/> refers to an equal map; <c>false</c> otherwise.</returns> + public bool Equals(MapField<TKey, TValue> other) + { + if (other == null) + { + return false; + } + if (other == this) + { + return true; + } + if (other.Count != this.Count) + { + return false; + } + var valueComparer = EqualityComparer<TValue>.Default; + foreach (var pair in this) + { + TValue value; + if (!other.TryGetValue(pair.Key, out value)) + { + return false; + } + if (!valueComparer.Equals(value, pair.Value)) + { + return false; + } + } + return true; + } + + /// <summary> + /// Adds entries to the map from the given stream. + /// </summary> + /// <remarks> + /// It is assumed that the stream is initially positioned after the tag specified by the codec. + /// This method will continue reading entries from the stream until the end is reached, or + /// a different tag is encountered. + /// </remarks> + /// <param name="input">Stream to read from</param> + /// <param name="codec">Codec describing how the key/value pairs are encoded</param> + public void AddEntriesFrom(CodedInputStream input, Codec codec) + { + var adapter = new Codec.MessageAdapter(codec); + do + { + adapter.Reset(); + input.ReadMessage(adapter); + this[adapter.Key] = adapter.Value; + } while (input.MaybeConsumeTag(codec.MapTag)); + } + + /// <summary> + /// Writes the contents of this map to the given coded output stream, using the specified codec + /// to encode each entry. + /// </summary> + /// <param name="output">The output stream to write to.</param> + /// <param name="codec">The codec to use for each entry.</param> + public void WriteTo(CodedOutputStream output, Codec codec) + { + var message = new Codec.MessageAdapter(codec); + foreach (var entry in list) + { + message.Key = entry.Key; + message.Value = entry.Value; + output.WriteTag(codec.MapTag); + output.WriteMessage(message); + } + } + + /// <summary> + /// Calculates the size of this map based on the given entry codec. + /// </summary> + /// <param name="codec">The codec to use to encode each entry.</param> + /// <returns></returns> + public int CalculateSize(Codec codec) + { + if (Count == 0) + { + return 0; + } + var message = new Codec.MessageAdapter(codec); + int size = 0; + foreach (var entry in list) + { + message.Key = entry.Key; + message.Value = entry.Value; + size += CodedOutputStream.ComputeRawVarint32Size(codec.MapTag); + size += CodedOutputStream.ComputeMessageSize(message); + } + return size; + } + + /// <summary> + /// Returns a string representation of this repeated field, in the same + /// way as it would be represented by the default JSON formatter. + /// </summary> + public override string ToString() + { + var writer = new StringWriter(); + JsonFormatter.Default.WriteDictionary(writer, this); + return writer.ToString(); + } + + #region IDictionary explicit interface implementation + void IDictionary.Add(object key, object value) + { + Add((TKey)key, (TValue)value); + } + + bool IDictionary.Contains(object key) + { + if (!(key is TKey)) + { + return false; + } + return ContainsKey((TKey)key); + } + + IDictionaryEnumerator IDictionary.GetEnumerator() + { + return new DictionaryEnumerator(GetEnumerator()); + } + + void IDictionary.Remove(object key) + { + ProtoPreconditions.CheckNotNull(key, nameof(key)); + if (!(key is TKey)) + { + return; + } + Remove((TKey)key); + } + + void ICollection.CopyTo(Array array, int index) + { + // This is ugly and slow as heck, but with any luck it will never be used anyway. + ICollection temp = this.Select(pair => new DictionaryEntry(pair.Key, pair.Value)).ToList(); + temp.CopyTo(array, index); + } + + bool IDictionary.IsFixedSize { get { return false; } } + + ICollection IDictionary.Keys { get { return (ICollection)Keys; } } + + ICollection IDictionary.Values { get { return (ICollection)Values; } } + + bool ICollection.IsSynchronized { get { return false; } } + + object ICollection.SyncRoot { get { return this; } } + + object IDictionary.this[object key] + { + get + { + ProtoPreconditions.CheckNotNull(key, nameof(key)); + if (!(key is TKey)) + { + return null; + } + TValue value; + TryGetValue((TKey)key, out value); + return value; + } + + set + { + this[(TKey)key] = (TValue)value; + } + } + #endregion + + private class DictionaryEnumerator : IDictionaryEnumerator + { + private readonly IEnumerator<KeyValuePair<TKey, TValue>> enumerator; + + internal DictionaryEnumerator(IEnumerator<KeyValuePair<TKey, TValue>> enumerator) + { + this.enumerator = enumerator; + } + + public bool MoveNext() + { + return enumerator.MoveNext(); + } + + public void Reset() + { + enumerator.Reset(); + } + + public object Current { get { return Entry; } } + public DictionaryEntry Entry { get { return new DictionaryEntry(Key, Value); } } + public object Key { get { return enumerator.Current.Key; } } + public object Value { get { return enumerator.Current.Value; } } + } + + /// <summary> + /// A codec for a specific map field. This contains all the information required to encode and + /// decode the nested messages. + /// </summary> + public sealed class Codec + { + private readonly FieldCodec<TKey> keyCodec; + private readonly FieldCodec<TValue> valueCodec; + private readonly uint mapTag; + + /// <summary> + /// Creates a new entry codec based on a separate key codec and value codec, + /// and the tag to use for each map entry. + /// </summary> + /// <param name="keyCodec">The key codec.</param> + /// <param name="valueCodec">The value codec.</param> + /// <param name="mapTag">The map tag to use to introduce each map entry.</param> + public Codec(FieldCodec<TKey> keyCodec, FieldCodec<TValue> valueCodec, uint mapTag) + { + this.keyCodec = keyCodec; + this.valueCodec = valueCodec; + this.mapTag = mapTag; + } + + /// <summary> + /// The tag used in the enclosing message to indicate map entries. + /// </summary> + internal uint MapTag { get { return mapTag; } } + + /// <summary> + /// A mutable message class, used for parsing and serializing. This + /// delegates the work to a codec, but implements the <see cref="IMessage"/> interface + /// for interop with <see cref="CodedInputStream"/> and <see cref="CodedOutputStream"/>. + /// This is nested inside Codec as it's tightly coupled to the associated codec, + /// and it's simpler if it has direct access to all its fields. + /// </summary> + internal class MessageAdapter : IMessage + { + private static readonly byte[] ZeroLengthMessageStreamData = new byte[] { 0 }; + + private readonly Codec codec; + internal TKey Key { get; set; } + internal TValue Value { get; set; } + + internal MessageAdapter(Codec codec) + { + this.codec = codec; + } + + internal void Reset() + { + Key = codec.keyCodec.DefaultValue; + Value = codec.valueCodec.DefaultValue; + } + + public void MergeFrom(CodedInputStream input) + { + uint tag; + while ((tag = input.ReadTag()) != 0) + { + if (tag == codec.keyCodec.Tag) + { + Key = codec.keyCodec.Read(input); + } + else if (tag == codec.valueCodec.Tag) + { + Value = codec.valueCodec.Read(input); + } + else + { + input.SkipLastField(); + } + } + + // Corner case: a map entry with a key but no value, where the value type is a message. + // Read it as if we'd seen an input stream with no data (i.e. create a "default" message). + if (Value == null) + { + Value = codec.valueCodec.Read(new CodedInputStream(ZeroLengthMessageStreamData)); + } + } + + public void WriteTo(CodedOutputStream output) + { + codec.keyCodec.WriteTagAndValue(output, Key); + codec.valueCodec.WriteTagAndValue(output, Value); + } + + public int CalculateSize() + { + return codec.keyCodec.CalculateSizeWithTag(Key) + codec.valueCodec.CalculateSizeWithTag(Value); + } + + MessageDescriptor IMessage.Descriptor { get { return null; } } + } + } + + private class MapView<T> : ICollection<T>, ICollection + { + private readonly MapField<TKey, TValue> parent; + private readonly Func<KeyValuePair<TKey, TValue>, T> projection; + private readonly Func<T, bool> containsCheck; + + internal MapView( + MapField<TKey, TValue> parent, + Func<KeyValuePair<TKey, TValue>, T> projection, + Func<T, bool> containsCheck) + { + this.parent = parent; + this.projection = projection; + this.containsCheck = containsCheck; + } + + public int Count { get { return parent.Count; } } + + public bool IsReadOnly { get { return true; } } + + public bool IsSynchronized { get { return false; } } + + public object SyncRoot { get { return parent; } } + + public void Add(T item) + { + throw new NotSupportedException(); + } + + public void Clear() + { + throw new NotSupportedException(); + } + + public bool Contains(T item) + { + return containsCheck(item); + } + + public void CopyTo(T[] array, int arrayIndex) + { + if (arrayIndex < 0) + { + throw new ArgumentOutOfRangeException(nameof(arrayIndex)); + } + if (arrayIndex + Count >= array.Length) + { + throw new ArgumentException("Not enough space in the array", nameof(array)); + } + foreach (var item in this) + { + array[arrayIndex++] = item; + } + } + + public IEnumerator<T> GetEnumerator() + { + return parent.list.Select(projection).GetEnumerator(); + } + + public bool Remove(T item) + { + throw new NotSupportedException(); + } + + IEnumerator IEnumerable.GetEnumerator() + { + return GetEnumerator(); + } + + public void CopyTo(Array array, int index) + { + if (index < 0) + { + throw new ArgumentOutOfRangeException(nameof(index)); + } + if (index + Count >= array.Length) + { + throw new ArgumentException("Not enough space in the array", nameof(array)); + } + foreach (var item in this) + { + array.SetValue(item, index++); + } + } + } + } +} |