#region Copyright notice and license | |
// Protocol Buffers - Google's data interchange format | |
// Copyright 2008 Google Inc. All rights reserved. | |
// http://github.com/jskeet/dotnet-protobufs/ | |
// Original C++/Java/Python code: | |
// http://code.google.com/p/protobuf/ | |
// | |
// 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.Reflection; | |
namespace Google.ProtocolBuffers | |
{ | |
/// <summary> | |
/// Utilities for arbitrary messages of an unknown type. This class does not use | |
/// generics precisely because it is designed for dynamically discovered types. | |
/// </summary> | |
public static class MessageUtil | |
{ | |
/// <summary> | |
/// Returns the default message for the given type. If an exception is thrown | |
/// (directly from this code), the message will be suitable to be displayed to a user. | |
/// </summary> | |
/// <param name="type"></param> | |
/// <exception cref="ArgumentNullException">The type parameter is null.</exception> | |
/// <exception cref="ArgumentException">The type doesn't implement IMessage, or doesn't | |
/// have a static DefaultMessage property of the same type, or is generic or abstract.</exception> | |
/// <returns></returns> | |
public static IMessage GetDefaultMessage(Type type) | |
{ | |
if (type == null) | |
{ | |
throw new ArgumentNullException("type", "No type specified."); | |
} | |
if (type.IsAbstract || type.IsGenericTypeDefinition) | |
{ | |
throw new ArgumentException("Unable to get a default message for an abstract or generic type (" + | |
type.FullName + ")"); | |
} | |
if (!typeof(IMessage).IsAssignableFrom(type)) | |
{ | |
throw new ArgumentException("Unable to get a default message for non-message type (" + type.FullName + | |
")"); | |
} | |
PropertyInfo property = type.GetProperty("DefaultInstance", | |
BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic); | |
if (property == null) | |
{ | |
throw new ArgumentException(type.FullName + " doesn't have a static DefaultInstance property"); | |
} | |
if (property.PropertyType != type) | |
{ | |
throw new ArgumentException(type.FullName + ".DefaultInstance property is of the wrong type"); | |
} | |
return (IMessage) property.GetValue(null, null); | |
} | |
/// <summary> | |
/// Returns the default message for the type with the given name. This is just | |
/// a convenience wrapper around calling Type.GetType and then GetDefaultMessage. | |
/// If an exception is thrown, the message will be suitable to be displayed to a user. | |
/// </summary> | |
/// <param name="typeName"></param> | |
/// <exception cref="ArgumentNullException">The typeName parameter is null.</exception> | |
/// <exception cref="ArgumentException">The type doesn't implement IMessage, or doesn't | |
/// have a static DefaultMessage property of the same type, or can't be found.</exception> | |
public static IMessage GetDefaultMessage(string typeName) | |
{ | |
if (typeName == null) | |
{ | |
throw new ArgumentNullException("typeName", "No type name specified."); | |
} | |
Type type = Type.GetType(typeName); | |
if (type == null) | |
{ | |
throw new ArgumentException("Unable to load type " + typeName); | |
} | |
return GetDefaultMessage(type); | |
} | |
} | |
} |