Squashed 'third_party/protobuf/' content from commit e35e248
Change-Id: I6cbe123d09fe50fdcad0e51466665daeee7433c7
git-subtree-dir: third_party/protobuf
git-subtree-split: e35e24800fb8d694bdeea5fd63dc7d1b14d68723
diff --git a/csharp/src/Google.Protobuf/FieldCodec.cs b/csharp/src/Google.Protobuf/FieldCodec.cs
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+#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.WellKnownTypes;
+using System;
+using System.Collections.Generic;
+
+namespace Google.Protobuf
+{
+ /// <summary>
+ /// Factory methods for <see cref="FieldCodec{T}"/>.
+ /// </summary>
+ public static class FieldCodec
+ {
+ // TODO: Avoid the "dual hit" of lambda expressions: create open delegates instead. (At least test...)
+
+ /// <summary>
+ /// Retrieves a codec suitable for a string field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<string> ForString(uint tag)
+ {
+ return new FieldCodec<string>(input => input.ReadString(), (output, value) => output.WriteString(value), CodedOutputStream.ComputeStringSize, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for a bytes field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<ByteString> ForBytes(uint tag)
+ {
+ return new FieldCodec<ByteString>(input => input.ReadBytes(), (output, value) => output.WriteBytes(value), CodedOutputStream.ComputeBytesSize, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for a bool field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<bool> ForBool(uint tag)
+ {
+ return new FieldCodec<bool>(input => input.ReadBool(), (output, value) => output.WriteBool(value), CodedOutputStream.ComputeBoolSize, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for an int32 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<int> ForInt32(uint tag)
+ {
+ return new FieldCodec<int>(input => input.ReadInt32(), (output, value) => output.WriteInt32(value), CodedOutputStream.ComputeInt32Size, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for an sint32 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<int> ForSInt32(uint tag)
+ {
+ return new FieldCodec<int>(input => input.ReadSInt32(), (output, value) => output.WriteSInt32(value), CodedOutputStream.ComputeSInt32Size, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for a fixed32 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<uint> ForFixed32(uint tag)
+ {
+ return new FieldCodec<uint>(input => input.ReadFixed32(), (output, value) => output.WriteFixed32(value), 4, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for an sfixed32 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<int> ForSFixed32(uint tag)
+ {
+ return new FieldCodec<int>(input => input.ReadSFixed32(), (output, value) => output.WriteSFixed32(value), 4, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for a uint32 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<uint> ForUInt32(uint tag)
+ {
+ return new FieldCodec<uint>(input => input.ReadUInt32(), (output, value) => output.WriteUInt32(value), CodedOutputStream.ComputeUInt32Size, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for an int64 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<long> ForInt64(uint tag)
+ {
+ return new FieldCodec<long>(input => input.ReadInt64(), (output, value) => output.WriteInt64(value), CodedOutputStream.ComputeInt64Size, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for an sint64 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<long> ForSInt64(uint tag)
+ {
+ return new FieldCodec<long>(input => input.ReadSInt64(), (output, value) => output.WriteSInt64(value), CodedOutputStream.ComputeSInt64Size, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for a fixed64 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<ulong> ForFixed64(uint tag)
+ {
+ return new FieldCodec<ulong>(input => input.ReadFixed64(), (output, value) => output.WriteFixed64(value), 8, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for an sfixed64 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<long> ForSFixed64(uint tag)
+ {
+ return new FieldCodec<long>(input => input.ReadSFixed64(), (output, value) => output.WriteSFixed64(value), 8, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for a uint64 field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<ulong> ForUInt64(uint tag)
+ {
+ return new FieldCodec<ulong>(input => input.ReadUInt64(), (output, value) => output.WriteUInt64(value), CodedOutputStream.ComputeUInt64Size, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for a float field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<float> ForFloat(uint tag)
+ {
+ return new FieldCodec<float>(input => input.ReadFloat(), (output, value) => output.WriteFloat(value), CodedOutputStream.ComputeFloatSize, tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for a double field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<double> ForDouble(uint tag)
+ {
+ return new FieldCodec<double>(input => input.ReadDouble(), (output, value) => output.WriteDouble(value), CodedOutputStream.ComputeDoubleSize, tag);
+ }
+
+ // Enums are tricky. We can probably use expression trees to build these delegates automatically,
+ // but it's easy to generate the code for it.
+
+ /// <summary>
+ /// Retrieves a codec suitable for an enum field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <param name="toInt32">A conversion function from <see cref="Int32"/> to the enum type.</param>
+ /// <param name="fromInt32">A conversion function from the enum type to <see cref="Int32"/>.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<T> ForEnum<T>(uint tag, Func<T, int> toInt32, Func<int, T> fromInt32)
+ {
+ return new FieldCodec<T>(input => fromInt32(
+ input.ReadEnum()),
+ (output, value) => output.WriteEnum(toInt32(value)),
+ value => CodedOutputStream.ComputeEnumSize(toInt32(value)), tag);
+ }
+
+ /// <summary>
+ /// Retrieves a codec suitable for a message field with the given tag.
+ /// </summary>
+ /// <param name="tag">The tag.</param>
+ /// <param name="parser">A parser to use for the message type.</param>
+ /// <returns>A codec for the given tag.</returns>
+ public static FieldCodec<T> ForMessage<T>(uint tag, MessageParser<T> parser) where T : IMessage<T>
+ {
+ return new FieldCodec<T>(input => { T message = parser.CreateTemplate(); input.ReadMessage(message); return message; },
+ (output, value) => output.WriteMessage(value), message => CodedOutputStream.ComputeMessageSize(message), tag);
+ }
+
+ /// <summary>
+ /// Creates a codec for a wrapper type of a class - which must be string or ByteString.
+ /// </summary>
+ public static FieldCodec<T> ForClassWrapper<T>(uint tag) where T : class
+ {
+ var nestedCodec = WrapperCodecs.GetCodec<T>();
+ return new FieldCodec<T>(
+ input => WrapperCodecs.Read<T>(input, nestedCodec),
+ (output, value) => WrapperCodecs.Write<T>(output, value, nestedCodec),
+ value => WrapperCodecs.CalculateSize<T>(value, nestedCodec),
+ tag,
+ null); // Default value for the wrapper
+ }
+
+ /// <summary>
+ /// Creates a codec for a wrapper type of a struct - which must be Int32, Int64, UInt32, UInt64,
+ /// Bool, Single or Double.
+ /// </summary>
+ public static FieldCodec<T?> ForStructWrapper<T>(uint tag) where T : struct
+ {
+ var nestedCodec = WrapperCodecs.GetCodec<T>();
+ return new FieldCodec<T?>(
+ input => WrapperCodecs.Read<T>(input, nestedCodec),
+ (output, value) => WrapperCodecs.Write<T>(output, value.Value, nestedCodec),
+ value => value == null ? 0 : WrapperCodecs.CalculateSize<T>(value.Value, nestedCodec),
+ tag,
+ null); // Default value for the wrapper
+ }
+
+ /// <summary>
+ /// Helper code to create codecs for wrapper types.
+ /// </summary>
+ /// <remarks>
+ /// Somewhat ugly with all the static methods, but the conversions involved to/from nullable types make it
+ /// slightly tricky to improve. So long as we keep the public API (ForClassWrapper, ForStructWrapper) in place,
+ /// we can refactor later if we come up with something cleaner.
+ /// </remarks>
+ private static class WrapperCodecs
+ {
+ private static readonly Dictionary<System.Type, object> Codecs = new Dictionary<System.Type, object>
+ {
+ { typeof(bool), ForBool(WireFormat.MakeTag(WrappersReflection.WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+ { typeof(int), ForInt32(WireFormat.MakeTag(WrappersReflection.WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+ { typeof(long), ForInt64(WireFormat.MakeTag(WrappersReflection.WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+ { typeof(uint), ForUInt32(WireFormat.MakeTag(WrappersReflection.WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+ { typeof(ulong), ForUInt64(WireFormat.MakeTag(WrappersReflection.WrapperValueFieldNumber, WireFormat.WireType.Varint)) },
+ { typeof(float), ForFloat(WireFormat.MakeTag(WrappersReflection.WrapperValueFieldNumber, WireFormat.WireType.Fixed32)) },
+ { typeof(double), ForDouble(WireFormat.MakeTag(WrappersReflection.WrapperValueFieldNumber, WireFormat.WireType.Fixed64)) },
+ { typeof(string), ForString(WireFormat.MakeTag(WrappersReflection.WrapperValueFieldNumber, WireFormat.WireType.LengthDelimited)) },
+ { typeof(ByteString), ForBytes(WireFormat.MakeTag(WrappersReflection.WrapperValueFieldNumber, WireFormat.WireType.LengthDelimited)) }
+ };
+
+ /// <summary>
+ /// Returns a field codec which effectively wraps a value of type T in a message.
+ ///
+ /// </summary>
+ internal static FieldCodec<T> GetCodec<T>()
+ {
+ object value;
+ if (!Codecs.TryGetValue(typeof(T), out value))
+ {
+ throw new InvalidOperationException("Invalid type argument requested for wrapper codec: " + typeof(T));
+ }
+ return (FieldCodec<T>) value;
+ }
+
+ internal static T Read<T>(CodedInputStream input, FieldCodec<T> codec)
+ {
+ int length = input.ReadLength();
+ int oldLimit = input.PushLimit(length);
+
+ uint tag;
+ T value = codec.DefaultValue;
+ while ((tag = input.ReadTag()) != 0)
+ {
+ if (tag == codec.Tag)
+ {
+ value = codec.Read(input);
+ }
+ else
+ {
+ input.SkipLastField();
+ }
+
+ }
+ input.CheckReadEndOfStreamTag();
+ input.PopLimit(oldLimit);
+
+ return value;
+ }
+
+ internal static void Write<T>(CodedOutputStream output, T value, FieldCodec<T> codec)
+ {
+ output.WriteLength(codec.CalculateSizeWithTag(value));
+ codec.WriteTagAndValue(output, value);
+ }
+
+ internal static int CalculateSize<T>(T value, FieldCodec<T> codec)
+ {
+ int fieldLength = codec.CalculateSizeWithTag(value);
+ return CodedOutputStream.ComputeLengthSize(fieldLength) + fieldLength;
+ }
+ }
+ }
+
+ /// <summary>
+ /// <para>
+ /// An encode/decode pair for a single field. This effectively encapsulates
+ /// all the information needed to read or write the field value from/to a coded
+ /// stream.
+ /// </para>
+ /// <para>
+ /// This class is public and has to be as it is used by generated code, but its public
+ /// API is very limited - just what the generated code needs to call directly.
+ /// </para>
+ /// </summary>
+ /// <remarks>
+ /// This never writes default values to the stream, and does not address "packedness"
+ /// in repeated fields itself, other than to know whether or not the field *should* be packed.
+ /// </remarks>
+ public sealed class FieldCodec<T>
+ {
+ private static readonly T DefaultDefault;
+ private static readonly bool TypeSupportsPacking = typeof(T).IsValueType() && Nullable.GetUnderlyingType(typeof(T)) == null;
+
+ static FieldCodec()
+ {
+ if (typeof(T) == typeof(string))
+ {
+ DefaultDefault = (T)(object)"";
+ }
+ else if (typeof(T) == typeof(ByteString))
+ {
+ DefaultDefault = (T)(object)ByteString.Empty;
+ }
+ // Otherwise it's the default value of the CLR type
+ }
+
+ internal static bool IsPackedRepeatedField(uint tag) =>
+ TypeSupportsPacking && WireFormat.GetTagWireType(tag) == WireFormat.WireType.LengthDelimited;
+
+ internal bool PackedRepeatedField { get; }
+
+ /// <summary>
+ /// Returns a delegate to write a value (unconditionally) to a coded output stream.
+ /// </summary>
+ internal Action<CodedOutputStream, T> ValueWriter { get; }
+
+ /// <summary>
+ /// Returns the size calculator for just a value.
+ /// </summary>
+ internal Func<T, int> ValueSizeCalculator { get; }
+
+ /// <summary>
+ /// Returns a delegate to read a value from a coded input stream. It is assumed that
+ /// the stream is already positioned on the appropriate tag.
+ /// </summary>
+ internal Func<CodedInputStream, T> ValueReader { get; }
+
+ /// <summary>
+ /// Returns the fixed size for an entry, or 0 if sizes vary.
+ /// </summary>
+ internal int FixedSize { get; }
+
+ /// <summary>
+ /// Gets the tag of the codec.
+ /// </summary>
+ /// <value>
+ /// The tag of the codec.
+ /// </value>
+ internal uint Tag { get; }
+
+ /// <summary>
+ /// Default value for this codec. Usually the same for every instance of the same type, but
+ /// for string/ByteString wrapper fields the codec's default value is null, whereas for
+ /// other string/ByteString fields it's "" or ByteString.Empty.
+ /// </summary>
+ /// <value>
+ /// The default value of the codec's type.
+ /// </value>
+ internal T DefaultValue { get; }
+
+ private readonly int tagSize;
+
+ internal FieldCodec(
+ Func<CodedInputStream, T> reader,
+ Action<CodedOutputStream, T> writer,
+ int fixedSize,
+ uint tag) : this(reader, writer, _ => fixedSize, tag)
+ {
+ FixedSize = fixedSize;
+ }
+
+ internal FieldCodec(
+ Func<CodedInputStream, T> reader,
+ Action<CodedOutputStream, T> writer,
+ Func<T, int> sizeCalculator,
+ uint tag) : this(reader, writer, sizeCalculator, tag, DefaultDefault)
+ {
+ }
+
+ internal FieldCodec(
+ Func<CodedInputStream, T> reader,
+ Action<CodedOutputStream, T> writer,
+ Func<T, int> sizeCalculator,
+ uint tag,
+ T defaultValue)
+ {
+ ValueReader = reader;
+ ValueWriter = writer;
+ ValueSizeCalculator = sizeCalculator;
+ FixedSize = 0;
+ Tag = tag;
+ DefaultValue = defaultValue;
+ tagSize = CodedOutputStream.ComputeRawVarint32Size(tag);
+ // Detect packed-ness once, so we can check for it within RepeatedField<T>.
+ PackedRepeatedField = IsPackedRepeatedField(tag);
+ }
+
+ /// <summary>
+ /// Write a tag and the given value, *if* the value is not the default.
+ /// </summary>
+ public void WriteTagAndValue(CodedOutputStream output, T value)
+ {
+ if (!IsDefault(value))
+ {
+ output.WriteTag(Tag);
+ ValueWriter(output, value);
+ }
+ }
+
+ /// <summary>
+ /// Reads a value of the codec type from the given <see cref="CodedInputStream"/>.
+ /// </summary>
+ /// <param name="input">The input stream to read from.</param>
+ /// <returns>The value read from the stream.</returns>
+ public T Read(CodedInputStream input) => ValueReader(input);
+
+ /// <summary>
+ /// Calculates the size required to write the given value, with a tag,
+ /// if the value is not the default.
+ /// </summary>
+ public int CalculateSizeWithTag(T value) => IsDefault(value) ? 0 : ValueSizeCalculator(value) + tagSize;
+
+ private bool IsDefault(T value) => EqualityComparer<T>.Default.Equals(value, DefaultValue);
+ }
+}