using System;
using System.Reflection;
using Google.ProtocolBuffers.Descriptors;
namespace Google.ProtocolBuffers.FieldAccess {
///
/// Accessor for fields representing a non-repeated message value.
///
internal sealed class SingleMessageAccessor : SinglePrimitiveAccessor {
///
/// The static method to create a builder for the property type. For example,
/// in a message type "Foo", a field called "bar" might be of type "Baz". This
/// method is Baz.CreateBuilder.
///
private readonly MethodInfo createBuilderMethod;
internal SingleMessageAccessor(string name, Type messageType, Type builderType)
: base(name, messageType, builderType) {
createBuilderMethod = ClrType.GetMethod("CreateBuilder", new Type[0]);//BindingFlags.Public | BindingFlags.Static | BindingFlags.DeclaredOnly);
if (createBuilderMethod == null) {
throw new ArgumentException("No public static CreateBuilder method declared in " + ClrType.Name);
}
}
///
/// Creates a message of the appropriate CLR type from the given value,
/// which may already be of the right type or may be a dynamic message.
///
private object CoerceType(object value) {
// If it's already of the right type, we're done
if (ClrType.IsInstanceOfType(value)) {
return value;
}
// No... so let's create a builder of the right type, and merge the value in.
IMessage message = (IMessage) value;
return CreateBuilder().WeakMergeFrom(message).WeakBuild();
}
public override void SetValue(IBuilder builder, object value) {
base.SetValue(builder, CoerceType(value));
}
public override IBuilder CreateBuilder() {
return (IBuilder) createBuilderMethod.Invoke(null, null);
}
}
}