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Diffstat (limited to 'csharp/src/Google.Protobuf/MessageParser.cs')
| -rw-r--r-- | csharp/src/Google.Protobuf/MessageParser.cs | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/csharp/src/Google.Protobuf/MessageParser.cs b/csharp/src/Google.Protobuf/MessageParser.cs new file mode 100644 index 00000000..8889638b --- /dev/null +++ b/csharp/src/Google.Protobuf/MessageParser.cs @@ -0,0 +1,267 @@ +#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.IO; + +namespace 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; + + internal MessageParser(Func<IMessage> factory) + { + this.factory = factory; + } + + /// <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) + { + ProtoPreconditions.CheckNotNull(data, "data"); + IMessage message = factory(); + message.MergeFrom(data); + 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) + { + ProtoPreconditions.CheckNotNull(data, "data"); + IMessage message = factory(); + message.MergeFrom(data); + 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); + 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); + 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(); + message.MergeFrom(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; + } + } + + /// <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) : base(() => factory()) + { + 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) + { + ProtoPreconditions.CheckNotNull(data, "data"); + T message = factory(); + message.MergeFrom(data); + 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) + { + ProtoPreconditions.CheckNotNull(data, "data"); + T message = factory(); + message.MergeFrom(data); + 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); + 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); + 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(); + message.MergeFrom(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; + } + } +} |