public static void EmitNullableExpression(this CompilationContext context, LocalBuilder local,
Action <CompilationContext> nonNullExpression, Action <CompilationContext> nullExpression)
{
var label = context.DefineLabel();
if (local.LocalType.IsNullable())
{
var variableType = local.LocalType.GetTypeInfo();
context.Emit(OpCodes.Ldloca, local);
context.EmitCall(variableType.GetProperty("HasValue").GetGetMethod());
context.Emit(OpCodes.Brfalse, label);
context.Emit(OpCodes.Ldloca, local);
context.EmitCall(variableType.GetProperty("Value").GetGetMethod());
context.CurrentType = variableType.GetGenericArguments()[0];
}
else
{
context.Emit(OpCodes.Ldloc, local);
context.Emit(OpCodes.Ldnull);
context.EmitCall(_referenceEqualsMethod);
context.Emit(OpCodes.Brtrue, label);
context.Emit(OpCodes.Ldloc, local);
context.CurrentType = local.LocalType;
}
nonNullExpression(context);
var labelEnd = context.DefineLabel();
context.Emit(OpCodes.Br, labelEnd);
context.MakeLabel(label);
nullExpression(context);
context.MakeLabel(labelEnd);
}
public void Emit(CompilationContext context)
{
context.EmitCall(_invokeMethod);
context.CurrentType = typeof(IEnumerable <TTarget>);
}
public void Emit(CompilationContext context)
{
context.EmitCall(_invokeMethod);
}
public void Emit(CompilationContext context)
{
context.EmitCall(_invokeMethod);
context.CurrentType = null;
}
public void Emit(CompilationContext context)
{
context.EmitCall(_invokeMethod);
context.CurrentType = typeof(TResult);
}
public static void EmitDefault(this CompilationContext context, Type targetType)
{
var originalType = targetType;
if (targetType.IsNullable())
{
var local = context.DeclareLocal(targetType);
context.Emit(OpCodes.Ldloca, local);
context.Emit(OpCodes.Initobj, targetType);
context.Emit(OpCodes.Ldloc, local);
context.CurrentType = originalType;
return;
}
if (!targetType.GetTypeInfo().IsValueType)
{
context.Emit(OpCodes.Ldnull);
context.CurrentType = originalType;
return;
}
if (targetType.GetTypeInfo().IsEnum)
{
targetType = Enum.GetUnderlyingType(targetType);
}
if (targetType == typeof(int) || targetType == typeof(uint) ||
targetType == typeof(short) || targetType == typeof(ushort) ||
targetType == typeof(byte) || targetType == typeof(sbyte) ||
targetType == typeof(char) || targetType == typeof(bool))
{
context.Emit(OpCodes.Ldc_I4_0);
context.CurrentType = originalType;
return;
}
if (targetType == typeof(long) || targetType == typeof(ulong))
{
context.Emit(OpCodes.Ldc_I4_0);
context.Emit(OpCodes.Conv_I8);
context.CurrentType = originalType;
return;
}
if (targetType == typeof(float))
{
context.Emit(OpCodes.Ldc_I4_0);
context.Emit(OpCodes.Conv_R4);
context.CurrentType = originalType;
return;
}
if (targetType == typeof(double))
{
context.Emit(OpCodes.Ldc_I4_0);
context.Emit(OpCodes.Conv_R8);
context.CurrentType = originalType;
return;
}
Func <MethodInfo, bool> coverterPredicate = method =>
{
if (method.Name == "op_Implicit")
{
var parameters = method.GetParameters();
return(parameters.Length == 1 && parameters[0].ParameterType == typeof(int));
}
return(false);
};
var reflectingType = targetType.GetTypeInfo();
if (targetType == typeof(decimal))
{
context.Emit(OpCodes.Ldc_I4_0);
context.EmitCall(reflectingType.GetMethods(BindingFlags.Static | BindingFlags.Public).FirstOrDefault(coverterPredicate));
context.CurrentType = originalType;
return;
}
var field = reflectingType.GetField("Empty", BindingFlags.Public | BindingFlags.Static) ??
reflectingType.GetField("Zero", BindingFlags.Public | BindingFlags.Static) ??
reflectingType.GetField("MinValue", BindingFlags.Public | BindingFlags.Static);
if (field != null)
{
context.Emit(OpCodes.Ldsfld, field);
context.CurrentType = field.FieldType;
context.EmitCast(originalType);
return;
}
var property = reflectingType.GetProperty("Empty", BindingFlags.Public | BindingFlags.Static) ??
reflectingType.GetProperty("Zero", BindingFlags.Public | BindingFlags.Static) ??
reflectingType.GetProperty("MinValue", BindingFlags.Public | BindingFlags.Static);
var getMethod = property?.GetGetMethod();
if (getMethod != null)
{
context.EmitCall(getMethod);
context.CurrentType = getMethod.ReturnType;
context.EmitCast(originalType);
return;
}
var targetLocal = context.DeclareLocal(targetType);
context.Emit(OpCodes.Ldloca, targetLocal);
context.Emit(OpCodes.Initobj, targetType);
context.Emit(OpCodes.Ldloc, targetLocal);
context.CurrentType = originalType;
}