/// <summary>
/// Compiles a DynamicMethodState and returns a delegate.
/// </summary>
/// <typeparam name="R">The return type of the expression</typeparam>
/// <typeparam name="C">The type of the function class</typeparam>
/// <param name="methodState">The serialized version of a method on the functionClass</param>
/// <returns>ExecuteExpression<R, C> - a delegate that calls the compiled expression</returns>
public ExecuteExpression <R, C> CreateExpressionDelegate <R, C>(DynamicMethodState methodState)
{
//create a dynamic method
var dynamicMethod = new DynamicMethod("_" + Guid.NewGuid().ToString("N"), typeof(R), new[] { typeof(C) }, typeof(C));
//get the IL writer for it
DynamicILInfo dynamicInfo = dynamicMethod.GetDynamicILInfo();
//set the properties gathered from the compiled expression
dynamicMethod.InitLocals = methodState.InitLocals;
//set local variables
SignatureHelper locals = SignatureHelper.GetLocalVarSigHelper();
foreach (int localIndex in methodState.LocalVariables.Keys)
{
LocalVariable localVar = methodState.LocalVariables[localIndex];
locals.AddArgument(Type.GetTypeFromHandle(localVar.LocalType), localVar.IsPinned);
}
dynamicInfo.SetLocalSignature(locals.GetSignature());
//resolve any metadata tokens
var tokenResolver = new IlTokenResolver(methodState.TokenOffset.Fields, methodState.TokenOffset.Methods, methodState.TokenOffset.Types, methodState.TokenOffset.LiteralStrings);
methodState.CodeBytes = tokenResolver.ResolveCodeTokens(methodState.CodeBytes, dynamicInfo);
//set the IL code for the dynamic method
dynamicInfo.SetCode(methodState.CodeBytes, methodState.MaxStackSize);
//create a delegate for fast execution
var expressionDelegate = (ExecuteExpression <R, C>)dynamicMethod.CreateDelegate(typeof(ExecuteExpression <R, C>));
return(expressionDelegate);
}
/// <summary>
/// Compiles a DynamicMethodState and returns a delegate.
/// </summary>
/// <typeparam name="R">The return type of the expression</typeparam>
/// <typeparam name="C">The type of the function class</typeparam>
/// <param name="methodState">The serialized version of a method on the functionClass</param>
/// <returns>EvalExpression<R, C> - a delegate that calls the compiled expression</returns>
internal EvalExpression <R, C> GetDelegate <R, C>(DynamicMethodState methodState)
{
ExecuteExpression <R, C> methodDelegate = null;
//get delegate factory
var delegateFactory = new ExpressionDelegateFactory();
if (methodState != null && methodState.CodeBytes != null)
{
//get delegate from factory
methodDelegate = delegateFactory.CreateExpressionDelegate <R, C>(methodState);
}
//return an eval delegate based on the delegate from the factory
return(new EvalExpression <R, C>(methodDelegate));
}
/// <summary>
/// Converts a MethodInfo into a serialized version of it.
/// </summary>
/// <param name="dynamicMethod">The method for which to create a DynamicMethod for</param>
/// <returns>DynamicMethodState - serialized version of a method.</returns>
protected DynamicMethodState GetMethodState(MethodInfo dynamicMethod)
{
var methodState = new DynamicMethodState();
//IL info from method
var methodIlCode = dynamicMethod.GetMethodBody();
//get code bytes and other method properties
methodState.CodeBytes = methodIlCode.GetILAsByteArray();
methodState.InitLocals = methodIlCode.InitLocals;
methodState.MaxStackSize = methodIlCode.MaxStackSize;
//get any local variable information
IDictionary <int, LocalVariable> locals = new SortedList <int, LocalVariable>();
foreach (var localInfo in methodIlCode.LocalVariables)
{
locals.Add(localInfo.LocalIndex, new LocalVariable(localInfo.IsPinned, localInfo.LocalType.TypeHandle));
}
methodState.LocalVariables = locals;
var tokenOffset = new TokenOffset();
//get metadata token offsets
var reader = new IlReader(methodState.CodeBytes, dynamicMethod.Module);
tokenOffset.Fields = reader.Fields;
tokenOffset.Methods = reader.Methods;
tokenOffset.Types = reader.Types;
tokenOffset.LiteralStrings = reader.LiteralStrings;
methodState.TokenOffset = tokenOffset;
return(methodState);
}
