csharp-sdk-upm/Libs/Google.Protobuf/MessageParser.cs

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2021-03-29 14:54:12 +08:00
#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.Buffers;
using System.IO;
using System.Security;
namespace LC.Google.Protobuf
{
/// <summary>
/// A general message parser, typically used by reflection-based code as all the methods
/// return simple <see cref="IMessage"/>.
/// </summary>
public class MessageParser
{
private Func<IMessage> factory;
// TODO: When we use a C# 7.1 compiler, make this private protected.
internal bool DiscardUnknownFields { get; }
internal ExtensionRegistry Extensions { get; }
internal MessageParser(Func<IMessage> factory, bool discardUnknownFields, ExtensionRegistry extensions)
{
this.factory = factory;
DiscardUnknownFields = discardUnknownFields;
Extensions = extensions;
}
/// <summary>
/// Creates a template instance ready for population.
/// </summary>
/// <returns>An empty message.</returns>
internal IMessage CreateTemplate()
{
return factory();
}
/// <summary>
/// Parses a message from a byte array.
/// </summary>
/// <param name="data">The byte array containing the message. Must not be null.</param>
/// <returns>The newly parsed message.</returns>
public IMessage ParseFrom(byte[] data)
{
IMessage message = factory();
message.MergeFrom(data, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from a byte array slice.
/// </summary>
/// <param name="data">The byte array containing the message. Must not be null.</param>
/// <param name="offset">The offset of the slice to parse.</param>
/// <param name="length">The length of the slice to parse.</param>
/// <returns>The newly parsed message.</returns>
public IMessage ParseFrom(byte[] data, int offset, int length)
{
IMessage message = factory();
message.MergeFrom(data, offset, length, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from the given byte string.
/// </summary>
/// <param name="data">The data to parse.</param>
/// <returns>The parsed message.</returns>
public IMessage ParseFrom(ByteString data)
{
IMessage message = factory();
message.MergeFrom(data, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from the given stream.
/// </summary>
/// <param name="input">The stream to parse.</param>
/// <returns>The parsed message.</returns>
public IMessage ParseFrom(Stream input)
{
IMessage message = factory();
message.MergeFrom(input, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from the given sequence.
/// </summary>
/// <param name="data">The data to parse.</param>
/// <returns>The parsed message.</returns>
[SecuritySafeCritical]
public IMessage ParseFrom(ReadOnlySequence<byte> data)
{
IMessage message = factory();
message.MergeFrom(data, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a length-delimited message from the given stream.
/// </summary>
/// <remarks>
/// The stream is expected to contain a length and then the data. Only the amount of data
/// specified by the length will be consumed.
/// </remarks>
/// <param name="input">The stream to parse.</param>
/// <returns>The parsed message.</returns>
public IMessage ParseDelimitedFrom(Stream input)
{
IMessage message = factory();
message.MergeDelimitedFrom(input, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from the given coded input stream.
/// </summary>
/// <param name="input">The stream to parse.</param>
/// <returns>The parsed message.</returns>
public IMessage ParseFrom(CodedInputStream input)
{
IMessage message = factory();
MergeFrom(message, input);
return message;
}
/// <summary>
/// Parses a message from the given JSON.
/// </summary>
/// <param name="json">The JSON to parse.</param>
/// <returns>The parsed message.</returns>
/// <exception cref="InvalidJsonException">The JSON does not comply with RFC 7159</exception>
/// <exception cref="InvalidProtocolBufferException">The JSON does not represent a Protocol Buffers message correctly</exception>
public IMessage ParseJson(string json)
{
IMessage message = factory();
JsonParser.Default.Merge(message, json);
return message;
}
// TODO: When we're using a C# 7.1 compiler, make this private protected.
internal void MergeFrom(IMessage message, CodedInputStream codedInput)
{
bool originalDiscard = codedInput.DiscardUnknownFields;
try
{
codedInput.DiscardUnknownFields = DiscardUnknownFields;
message.MergeFrom(codedInput);
}
finally
{
codedInput.DiscardUnknownFields = originalDiscard;
}
}
/// <summary>
/// Creates a new message parser which optionally discards unknown fields when parsing.
/// </summary>
/// <param name="discardUnknownFields">Whether or not to discard unknown fields when parsing.</param>
/// <returns>A newly configured message parser.</returns>
public MessageParser WithDiscardUnknownFields(bool discardUnknownFields) =>
new MessageParser(factory, discardUnknownFields, Extensions);
/// <summary>
/// Creates a new message parser which registers extensions from the specified registry upon creating the message instance
/// </summary>
/// <param name="registry">The extensions to register</param>
/// <returns>A newly configured message parser.</returns>
public MessageParser WithExtensionRegistry(ExtensionRegistry registry) =>
new MessageParser(factory, DiscardUnknownFields, registry);
}
/// <summary>
/// A parser for a specific message type.
/// </summary>
/// <remarks>
/// <p>
/// This delegates most behavior to the
/// <see cref="IMessage.MergeFrom"/> implementation within the original type, but
/// provides convenient overloads to parse from a variety of sources.
/// </p>
/// <p>
/// Most applications will never need to create their own instances of this type;
/// instead, use the static <c>Parser</c> property of a generated message type to obtain a
/// parser for that type.
/// </p>
/// </remarks>
/// <typeparam name="T">The type of message to be parsed.</typeparam>
public sealed class MessageParser<T> : MessageParser where T : IMessage<T>
{
// Implementation note: all the methods here *could* just delegate up to the base class and cast the result.
// The current implementation avoids a virtual method call and a cast, which *may* be significant in some cases.
// Benchmarking work is required to measure the significance - but it's only a few lines of code in any case.
// The API wouldn't change anyway - just the implementation - so this work can be deferred.
private readonly Func<T> factory;
/// <summary>
/// Creates a new parser.
/// </summary>
/// <remarks>
/// The factory method is effectively an optimization over using a generic constraint
/// to require a parameterless constructor: delegates are significantly faster to execute.
/// </remarks>
/// <param name="factory">Function to invoke when a new, empty message is required.</param>
public MessageParser(Func<T> factory) : this(factory, false, null)
{
}
internal MessageParser(Func<T> factory, bool discardUnknownFields, ExtensionRegistry extensions) : base(() => factory(), discardUnknownFields, extensions)
{
this.factory = factory;
}
/// <summary>
/// Creates a template instance ready for population.
/// </summary>
/// <returns>An empty message.</returns>
internal new T CreateTemplate()
{
return factory();
}
/// <summary>
/// Parses a message from a byte array.
/// </summary>
/// <param name="data">The byte array containing the message. Must not be null.</param>
/// <returns>The newly parsed message.</returns>
public new T ParseFrom(byte[] data)
{
T message = factory();
message.MergeFrom(data, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from a byte array slice.
/// </summary>
/// <param name="data">The byte array containing the message. Must not be null.</param>
/// <param name="offset">The offset of the slice to parse.</param>
/// <param name="length">The length of the slice to parse.</param>
/// <returns>The newly parsed message.</returns>
public new T ParseFrom(byte[] data, int offset, int length)
{
T message = factory();
message.MergeFrom(data, offset, length, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from the given byte string.
/// </summary>
/// <param name="data">The data to parse.</param>
/// <returns>The parsed message.</returns>
public new T ParseFrom(ByteString data)
{
T message = factory();
message.MergeFrom(data, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from the given stream.
/// </summary>
/// <param name="input">The stream to parse.</param>
/// <returns>The parsed message.</returns>
public new T ParseFrom(Stream input)
{
T message = factory();
message.MergeFrom(input, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from the given sequence.
/// </summary>
/// <param name="data">The data to parse.</param>
/// <returns>The parsed message.</returns>
[SecuritySafeCritical]
public new T ParseFrom(ReadOnlySequence<byte> data)
{
T message = factory();
message.MergeFrom(data, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a length-delimited message from the given stream.
/// </summary>
/// <remarks>
/// The stream is expected to contain a length and then the data. Only the amount of data
/// specified by the length will be consumed.
/// </remarks>
/// <param name="input">The stream to parse.</param>
/// <returns>The parsed message.</returns>
public new T ParseDelimitedFrom(Stream input)
{
T message = factory();
message.MergeDelimitedFrom(input, DiscardUnknownFields, Extensions);
return message;
}
/// <summary>
/// Parses a message from the given coded input stream.
/// </summary>
/// <param name="input">The stream to parse.</param>
/// <returns>The parsed message.</returns>
public new T ParseFrom(CodedInputStream input)
{
T message = factory();
MergeFrom(message, input);
return message;
}
/// <summary>
/// Parses a message from the given JSON.
/// </summary>
/// <param name="json">The JSON to parse.</param>
/// <returns>The parsed message.</returns>
/// <exception cref="InvalidJsonException">The JSON does not comply with RFC 7159</exception>
/// <exception cref="InvalidProtocolBufferException">The JSON does not represent a Protocol Buffers message correctly</exception>
public new T ParseJson(string json)
{
T message = factory();
JsonParser.Default.Merge(message, json);
return message;
}
/// <summary>
/// Creates a new message parser which optionally discards unknown fields when parsing.
/// </summary>
/// <param name="discardUnknownFields">Whether or not to discard unknown fields when parsing.</param>
/// <returns>A newly configured message parser.</returns>
public new MessageParser<T> WithDiscardUnknownFields(bool discardUnknownFields) =>
new MessageParser<T>(factory, discardUnknownFields, Extensions);
/// <summary>
/// Creates a new message parser which registers extensions from the specified registry upon creating the message instance
/// </summary>
/// <param name="registry">The extensions to register</param>
/// <returns>A newly configured message parser.</returns>
public new MessageParser<T> WithExtensionRegistry(ExtensionRegistry registry) =>
new MessageParser<T>(factory, DiscardUnknownFields, registry);
}
}