private Expression <ReadDelegate <T> > GetLambdaExpression <T>()
{
var brParameter = Expression.Parameter(typeof(BitsReader), "br");
Dictionary <Type, Expression <ReadFunc> > typeReaders = Types.ToDictionary(pair => pair.Key, pair =>
{
var args = new ExpressionBuilderArgs();
args.BrParameter = brParameter;
args.InstanceVar = Expression.Parameter(typeof(Object));
args.TypeReaders = Expression.Parameter(typeof(Dictionary <Type, Expression <ReadFunc> >));
args.Endianness = Expression.Constant(_endianness);
var expression = pair.Value.BuildExpression(args);
return(Expression.Lambda <ReadFunc>(expression, string.Format("Read_{0}", pair.Key.Name),
new[] { args.BrParameter, args.InstanceVar, args.TypeReaders }));
});
var resultVar = Expression.Variable(typeof(T), "root");
var brCheckExpression = Expression.IfThen(Expression.Equal(brParameter, Expression.Constant(null)),
Expression.Throw(Expression.New(typeof(ArgumentNullException).GetConstructor(new[] { typeof(String) }), Expression.Constant(brParameter.Name, typeof(String)))));
var ctorExpression = Expression.Assign(resultVar, Expression.New(typeof(T)));
var typeReadersVar = Expression.Variable(typeof(Dictionary <Type, Expression <ReadFunc> >));
var typeReadExpression = Expression.Block(new[] { resultVar, typeReadersVar },
brCheckExpression,
CreateTypeReaders(typeReadersVar, typeReaders),
ctorExpression,
Expression.Invoke(AdvancedExpression.GetTypeBuilder(typeReadersVar, Expression.Constant(typeof(T))),
brParameter, resultVar, typeReadersVar),
resultVar);
return(Expression.Lambda <ReadDelegate <T> >(typeReadExpression, string.Format("Read_Root", typeof(T).Name), new[] { brParameter }));
}
protected override Expression BuildBodyExpression(ExpressionBuilderArgs args, ParameterExpression innerResultVar, ParameterExpression typeVar)
{
return(Expression.Block(AdvancedExpression.Debug("Type: {0}", typeVar),
Expression.Invoke(AdvancedExpression.GetTypeBuilder(args.TypeReaders, typeVar),
args.BrParameter, innerResultVar, args.TypeReaders)));
}
