From 59eeebee870332ea2b9085688ba524c69311f662 Mon Sep 17 00:00:00 2001 From: Jon Skeet Date: Fri, 17 Jul 2015 08:26:04 +0100 Subject: First pass at the big rename from ProtocolBuffers to Google.Protobuf. We'll see what I've missed when CI fails... --- csharp/src/Google.Protobuf/FieldCodec.cs | 382 +++++++++++++++++++++++++++++++ 1 file changed, 382 insertions(+) create mode 100644 csharp/src/Google.Protobuf/FieldCodec.cs (limited to 'csharp/src/Google.Protobuf/FieldCodec.cs') diff --git a/csharp/src/Google.Protobuf/FieldCodec.cs b/csharp/src/Google.Protobuf/FieldCodec.cs new file mode 100644 index 00000000..85462787 --- /dev/null +++ b/csharp/src/Google.Protobuf/FieldCodec.cs @@ -0,0 +1,382 @@ +#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 System; +using System.Collections.Generic; + +namespace Google.Protobuf +{ + /// + /// Factory methods for . + /// + public static class FieldCodec + { + // TODO: Avoid the "dual hit" of lambda expressions: create open delegates instead. (At least test...) + public static FieldCodec ForString(uint tag) + { + return new FieldCodec(input => input.ReadString(), (output, value) => output.WriteString(value), CodedOutputStream.ComputeStringSize, tag); + } + + public static FieldCodec ForBytes(uint tag) + { + return new FieldCodec(input => input.ReadBytes(), (output, value) => output.WriteBytes(value), CodedOutputStream.ComputeBytesSize, tag); + } + + public static FieldCodec ForBool(uint tag) + { + return new FieldCodec(input => input.ReadBool(), (output, value) => output.WriteBool(value), CodedOutputStream.ComputeBoolSize, tag); + } + + public static FieldCodec ForInt32(uint tag) + { + return new FieldCodec(input => input.ReadInt32(), (output, value) => output.WriteInt32(value), CodedOutputStream.ComputeInt32Size, tag); + } + + public static FieldCodec ForSInt32(uint tag) + { + return new FieldCodec(input => input.ReadSInt32(), (output, value) => output.WriteSInt32(value), CodedOutputStream.ComputeSInt32Size, tag); + } + + public static FieldCodec ForFixed32(uint tag) + { + return new FieldCodec(input => input.ReadFixed32(), (output, value) => output.WriteFixed32(value), 4, tag); + } + + public static FieldCodec ForSFixed32(uint tag) + { + return new FieldCodec(input => input.ReadSFixed32(), (output, value) => output.WriteSFixed32(value), 4, tag); + } + + public static FieldCodec ForUInt32(uint tag) + { + return new FieldCodec(input => input.ReadUInt32(), (output, value) => output.WriteUInt32(value), CodedOutputStream.ComputeUInt32Size, tag); + } + + public static FieldCodec ForInt64(uint tag) + { + return new FieldCodec(input => input.ReadInt64(), (output, value) => output.WriteInt64(value), CodedOutputStream.ComputeInt64Size, tag); + } + + public static FieldCodec ForSInt64(uint tag) + { + return new FieldCodec(input => input.ReadSInt64(), (output, value) => output.WriteSInt64(value), CodedOutputStream.ComputeSInt64Size, tag); + } + + public static FieldCodec ForFixed64(uint tag) + { + return new FieldCodec(input => input.ReadFixed64(), (output, value) => output.WriteFixed64(value), 8, tag); + } + + public static FieldCodec ForSFixed64(uint tag) + { + return new FieldCodec(input => input.ReadSFixed64(), (output, value) => output.WriteSFixed64(value), 8, tag); + } + + public static FieldCodec ForUInt64(uint tag) + { + return new FieldCodec(input => input.ReadUInt64(), (output, value) => output.WriteUInt64(value), CodedOutputStream.ComputeUInt64Size, tag); + } + + public static FieldCodec ForFloat(uint tag) + { + return new FieldCodec(input => input.ReadFloat(), (output, value) => output.WriteFloat(value), CodedOutputStream.ComputeFloatSize, tag); + } + + public static FieldCodec ForDouble(uint tag) + { + return new FieldCodec(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. + public static FieldCodec ForEnum(uint tag, Func toInt32, Func fromInt32) + { + return new FieldCodec(input => fromInt32( + input.ReadEnum()), + (output, value) => output.WriteEnum(toInt32(value)), + value => CodedOutputStream.ComputeEnumSize(toInt32(value)), tag); + } + + public static FieldCodec ForMessage(uint tag, MessageParser parser) where T : IMessage + { + return new FieldCodec(input => { T message = parser.CreateTemplate(); input.ReadMessage(message); return message; }, + (output, value) => output.WriteMessage(value), message => CodedOutputStream.ComputeMessageSize(message), tag); + } + + /// + /// Creates a codec for a wrapper type of a class - which must be string or ByteString. + /// + public static FieldCodec ForClassWrapper(uint tag) where T : class + { + var nestedCodec = WrapperCodecs.GetCodec(); + return new FieldCodec( + input => WrapperCodecs.Read(input, nestedCodec), + (output, value) => WrapperCodecs.Write(output, value, nestedCodec), + value => WrapperCodecs.CalculateSize(value, nestedCodec), + tag, + null); // Default value for the wrapper + } + + /// + /// Creates a codec for a wrapper type of a struct - which must be Int32, Int64, UInt32, UInt64, + /// Bool, Single or Double. + /// + public static FieldCodec ForStructWrapper(uint tag) where T : struct + { + var nestedCodec = WrapperCodecs.GetCodec(); + return new FieldCodec( + input => WrapperCodecs.Read(input, nestedCodec), + (output, value) => WrapperCodecs.Write(output, value.Value, nestedCodec), + value => value == null ? 0 : WrapperCodecs.CalculateSize(value.Value, nestedCodec), + tag, + null); // Default value for the wrapper + } + + /// + /// Helper code to create codecs for wrapper types. + /// + /// + /// 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. + /// + private static class WrapperCodecs + { + // All the field numbers are the same (1). + private const int WrapperValueFieldNumber = Google.Protobuf.WellKnownTypes.Int32Value.ValueFieldNumber; + + private static readonly Dictionary Codecs = new Dictionary + { + { typeof(bool), ForBool(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) }, + { typeof(int), ForInt32(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) }, + { typeof(long), ForInt64(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) }, + { typeof(uint), ForUInt32(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) }, + { typeof(ulong), ForUInt64(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Varint)) }, + { typeof(float), ForFloat(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Fixed32)) }, + { typeof(double), ForDouble(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.Fixed64)) }, + { typeof(string), ForString(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.LengthDelimited)) }, + { typeof(ByteString), ForBytes(WireFormat.MakeTag(WrapperValueFieldNumber, WireFormat.WireType.LengthDelimited)) } + }; + + /// + /// Returns a field codec which effectively wraps a value of type T in a message. + /// + /// + internal static FieldCodec GetCodec() + { + object value; + if (!Codecs.TryGetValue(typeof(T), out value)) + { + throw new InvalidOperationException("Invalid type argument requested for wrapper codec: " + typeof(T)); + } + return (FieldCodec) value; + } + + internal static T Read(CodedInputStream input, FieldCodec codec) + { + int length = input.ReadLength(); + int oldLimit = input.PushLimit(length); + + uint tag; + T value = codec.DefaultValue; + while (input.ReadTag(out tag)) + { + if (tag == 0) + { + throw InvalidProtocolBufferException.InvalidTag(); + } + if (tag == codec.Tag) + { + value = codec.Read(input); + } + if (WireFormat.IsEndGroupTag(tag)) + { + break; + } + } + input.CheckLastTagWas(0); + input.PopLimit(oldLimit); + + return value; + } + + internal static void Write(CodedOutputStream output, T value, FieldCodec codec) + { + output.WriteLength(codec.CalculateSizeWithTag(value)); + codec.WriteTagAndValue(output, value); + } + + internal static int CalculateSize(T value, FieldCodec codec) + { + int fieldLength = codec.CalculateSizeWithTag(value); + return CodedOutputStream.ComputeLengthSize(fieldLength) + fieldLength; + } + } + } + + /// + /// 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. + /// + /// + /// This never writes default values to the stream, and is not currently designed + /// to play well with packed arrays. + /// + public sealed class FieldCodec + { + private static readonly T DefaultDefault; + + 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 + } + + private static Func CreateDefaultValueCheck(Func check) + { + return (Func)(object)check; + } + + private readonly Func reader; + private readonly Action writer; + private readonly Func sizeCalculator; + private readonly uint tag; + private readonly int tagSize; + private readonly int fixedSize; + // 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. + private readonly T defaultValue; + + internal FieldCodec( + Func reader, + Action writer, + Func sizeCalculator, + uint tag) : this(reader, writer, sizeCalculator, tag, DefaultDefault) + { + } + + internal FieldCodec( + Func reader, + Action writer, + Func sizeCalculator, + uint tag, + T defaultValue) + { + this.reader = reader; + this.writer = writer; + this.sizeCalculator = sizeCalculator; + this.fixedSize = 0; + this.tag = tag; + this.defaultValue = defaultValue; + tagSize = CodedOutputStream.ComputeRawVarint32Size(tag); + } + + internal FieldCodec( + Func reader, + Action writer, + int fixedSize, + uint tag) + { + this.reader = reader; + this.writer = writer; + this.sizeCalculator = _ => fixedSize; + this.fixedSize = fixedSize; + this.tag = tag; + tagSize = CodedOutputStream.ComputeRawVarint32Size(tag); + } + + /// + /// Returns the size calculator for just a value. + /// + internal Func ValueSizeCalculator { get { return sizeCalculator; } } + + /// + /// Returns a delegate to write a value (unconditionally) to a coded output stream. + /// + internal Action ValueWriter { get { return writer; } } + + /// + /// 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. + /// + internal Func ValueReader { get { return reader; } } + + /// + /// Returns the fixed size for an entry, or 0 if sizes vary. + /// + internal int FixedSize { get { return fixedSize; } } + + public uint Tag { get { return tag; } } + + public T DefaultValue { get { return defaultValue; } } + + /// + /// Write a tag and the given value, *if* the value is not the default. + /// + public void WriteTagAndValue(CodedOutputStream output, T value) + { + if (!IsDefault(value)) + { + output.WriteTag(tag); + writer(output, value); + } + } + + public T Read(CodedInputStream input) + { + return reader(input); + } + + /// + /// Calculates the size required to write the given value, with a tag, + /// if the value is not the default. + /// + public int CalculateSizeWithTag(T value) + { + return IsDefault(value) ? 0 : sizeCalculator(value) + tagSize; + } + + private bool IsDefault(T value) + { + return EqualityComparer.Default.Equals(value, defaultValue); + } + } +} -- cgit v1.2.3