private static MethodInfo GetSqlMapperQueryMethod(MappingFunctionDescriptor funcDescriptor)
{
MethodInfo firstOrDefault =
typeof(SqlMapper).GetMethods()
.FirstOrDefault(
m =>
m.Name == "Query" && m.IsGenericMethod &&
m.GetGenericArguments().Length == funcDescriptor.GenericTypes.Length);
if (firstOrDefault != null)
{
return(firstOrDefault.MakeGenericMethod(funcDescriptor.GenericTypes));
}
return(null);
}
BuildFunction <TReturn, TFunc>()
{
var mappingDescriptor = new MappingFunctionDescriptor(typeof(TFunc));
MethodInfo queryMethodSignature = GetSqlMapperQueryMethod(mappingDescriptor);
// variables that are visible in main scope
var variables = new List <ParameterExpression>();
//body of main query method
var methodBodyExpressions = new List <Expression>();
////query method incoming parameters
//var queryMethodParameters = new List<ParameterExpression>();
// parameters for fake map function
var mappingParameters = new List <ParameterExpression>();
// body for fake map function
var mappingBodyExpressions = new List <Expression>();
// declare and assign dictionaries and id evaluators for mapped types
foreach (Type type in mappingDescriptor.GenericTypes.Take(mappingDescriptor.GenericTypes.Length - 1))
{
IStructureMap mapper = LeanMapper.GetMapper(type);
mappingParameters.Add(Expression.Parameter(type));
if (mapper == null)
{
continue;
}
SetupIdDataChecker(variables, methodBodyExpressions, mappingParameters.Last(), mappingBodyExpressions,
mapper);
}
// declare parameters for main query method (they will be passed down to inner SqlMapper.Query method call)
ParameterExpression cnnP = Expression.Parameter(typeof(IDbConnection), "cnn");
ParameterExpression sqlP = Expression.Parameter(typeof(string), "sql");
ParameterExpression mapParam = Expression.Parameter(mappingDescriptor.MappingType, "map");
ParameterExpression paramP = Expression.Parameter(typeof(object), "param");
ParameterExpression transactionP = Expression.Parameter(typeof(IDbTransaction), "transaction");
ParameterExpression bufferedP = Expression.Parameter(typeof(bool), "buffered");
ParameterExpression splitOnP = Expression.Parameter(typeof(string), "splitOn");
ParameterExpression commandTimeoutP = Expression.Parameter(typeof(int?), "commandTimeout");
ParameterExpression commandTypeP = Expression.Parameter(typeof(CommandType?), "commandType");
ParameterExpression newMapper = Expression.Parameter(mappingDescriptor.MappingType, "newMapper");
methodBodyExpressions.Add(Expression.Assign(newMapper,
FinishFakeMappingFunction <TReturn, TFunc>(mapParam, mappingParameters, mappingBodyExpressions)));
variables.Add(newMapper);
//call REAL Query Method
MethodCallExpression callRealDapperMethod = Expression.Call(queryMethodSignature, cnnP, sqlP, newMapper,
paramP, transactionP, bufferedP, splitOnP, commandTimeoutP, commandTypeP);
LabelTarget returnFinalTarget = Expression.Label(typeof(IEnumerable <TReturn>));
GotoExpression returnFinalValue = Expression.Return(returnFinalTarget, callRealDapperMethod);
LabelExpression rerturnFinalExpression = Expression.Label(returnFinalTarget,
Expression.Default(typeof(IEnumerable <TReturn>)));
methodBodyExpressions.Add(returnFinalValue);
methodBodyExpressions.Add(rerturnFinalExpression);
return
(Expression
.Lambda
<Func <IDbConnection, string, TFunc, dynamic, IDbTransaction, bool, string, int?, CommandType?,
IEnumerable <TReturn> > >(
Expression.Block(variables, methodBodyExpressions),
cnnP, sqlP, mapParam, paramP, transactionP, bufferedP, splitOnP, commandTimeoutP,
commandTypeP).Compile());
}
