Files
OpenRA/OpenRA.Game/ObjectCreator.cs
2010-09-22 08:01:57 +12:00

92 lines
2.6 KiB
C#
Executable File

using System;
using System.IO;
using System.Linq;
using System.Reflection;
using OpenRA.FileFormats;
using System.Collections.Generic;
namespace OpenRA
{
public class ObjectCreator
{
Pair<Assembly, string>[] ModAssemblies;
public ObjectCreator( Manifest manifest )
{
// All the core namespaces
var asms = typeof(Game).Assembly.GetNamespaces()
.Select(c => Pair.New(typeof(Game).Assembly, c))
.ToList();
// Namespaces from each mod assembly
foreach (var a in manifest.Assemblies)
{
var asm = Assembly.LoadFile(Path.GetFullPath(a));
asms.AddRange(asm.GetNamespaces().Select(ns => Pair.New(asm, ns)));
}
ModAssemblies = asms.ToArray();
}
public static Action<string> MissingTypeAction =
s => { throw new InvalidOperationException("Cannot locate type: {0}".F(s)); };
public T CreateObject<T>(string className)
{
return CreateObject<T>( className, new Dictionary<string, object>() );
}
public T CreateObject<T>( string className, Dictionary<string, object> args )
{
foreach( var mod in ModAssemblies )
{
var type = mod.First.GetType( mod.Second + "." + className, false );
if( type == null ) continue;
var ctors = type.GetConstructors().Where( x => x.HasAttribute<UseCtorAttribute>() ).ToList();
if( ctors.Count == 0 )
return (T)CreateBasic( type );
else if( ctors.Count == 1 )
return (T)CreateUsingArgs( ctors[ 0 ], args );
else
throw new InvalidOperationException( "ObjectCreator: UseCtor on multiple constructors; invalid." );
}
MissingTypeAction(className);
return default(T);
}
public object CreateBasic( Type type )
{
return type.GetConstructor( new Type[ 0 ] ).Invoke( new object[ 0 ] );
}
public object CreateUsingArgs( ConstructorInfo ctor, Dictionary<string, object> args )
{
var p = ctor.GetParameters();
var a = new object[ p.Length ];
for( int i = 0 ; i < p.Length ; i++ )
{
var attrs = p[ i ].GetCustomAttributes<ParamAttribute>();
if( attrs.Length != 1 ) throw new InvalidOperationException( "ObjectCreator: argument in [UseCtor] doesn't have [Param]" );
a[ i ] = args[ attrs[ 0 ].ParamName ];
}
return ctor.Invoke( a );
}
[AttributeUsage( AttributeTargets.Parameter )]
public class ParamAttribute : Attribute
{
public string ParamName { get; private set; }
public ParamAttribute( string paramName )
{
ParamName = paramName;
}
}
[AttributeUsage( AttributeTargets.Constructor )]
public class UseCtorAttribute : Attribute
{
}
}
}