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Diffstat (limited to 'third_party/protobuf/3.6.0/csharp/src/Google.Protobuf/FieldCodec.cs')
| -rw-r--r-- | third_party/protobuf/3.6.0/csharp/src/Google.Protobuf/FieldCodec.cs | 476 |
1 files changed, 476 insertions, 0 deletions
diff --git a/third_party/protobuf/3.6.0/csharp/src/Google.Protobuf/FieldCodec.cs b/third_party/protobuf/3.6.0/csharp/src/Google.Protobuf/FieldCodec.cs new file mode 100644 index 0000000000..a11f2420e3 --- /dev/null +++ b/third_party/protobuf/3.6.0/csharp/src/Google.Protobuf/FieldCodec.cs @@ -0,0 +1,476 @@ +#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.Collections; +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 EqualityComparer<T> EqualityComparer = ProtobufEqualityComparers.GetEqualityComparer<T>(); + private static readonly T DefaultDefault; + // Only non-nullable value types support packing. This is the simplest way of detecting that. + private static readonly bool TypeSupportsPacking = default(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.Equals(value, DefaultValue); + } +} |