public static Tuple <Type, string> Generate <TOuterKey, TSource, TInnerKey>(
Expression <Func <TInnerKey, int> > hashComparer,
Expression <Func <TSource, TInnerKey> > keySelector,
bool nested)
{
var typeOfTOuterKey = typeof(TOuterKey);
var typeOfTSource = typeof(TSource);
var typeOfTInnerKey = typeof(TInnerKey);
string expandedCode;
List <Assembly> assemblyReferences;
string errorMessages = null;
try
{
string generatedClassName = $"GeneratedGroupStreamable_{GroupStreamableSequenceNumber++}";
string transformedKeySelectorAsString;
MyFieldInfo swingingField = default;
if (typeOfTInnerKey.IsAnonymousTypeName())
{
Contract.Assume(keySelector.Body is NewExpression);
var transformedFunction = Extensions.TransformUnaryFunction <TOuterKey, TSource>(keySelector);
var newBody = (NewExpression)transformedFunction.Body;
transformedKeySelectorAsString = string.Join(",", newBody.Arguments.Select(arg => arg.ExpressionToCSharp()));
}
else
{
var body = keySelector.Body;
if (!nested && body is MemberExpression singleFieldProjection)
{
if (singleFieldProjection.Expression is ParameterExpression dereferencedObject)
{
// then can just swing a pointer to set the key of the result message
Contract.Assume(dereferencedObject == keySelector.Parameters.ElementAt(0));
var f = singleFieldProjection.Member;
var sourceMessageRepresentation = new ColumnarRepresentation(typeOfTSource);
var fieldToSwingFrom = sourceMessageRepresentation.Fields[f.Name];
swingingField = fieldToSwingFrom;
transformedKeySelectorAsString = swingingField.Name + "_col[i]";
}
else
{
var transformedPredicate = Extensions.TransformUnaryFunction <TOuterKey, TSource>(keySelector).Body;
if (transformedPredicate == null)
{
return(Tuple.Create((Type)null, errorMessages));
}
transformedKeySelectorAsString = transformedPredicate.ExpressionToCSharp();
}
}
else
{
var transformedPredicate = Extensions.TransformUnaryFunction <TOuterKey, TSource>(keySelector).Body;
if (transformedPredicate == null)
{
return(Tuple.Create((Type)null, errorMessages));
}
transformedKeySelectorAsString = transformedPredicate.ExpressionToCSharp();
}
}
var inlinedHashCodeComputation = hashComparer.Inline("key");
var template = new GroupTemplate(
generatedClassName,
typeOfTOuterKey,
typeOfTSource,
typeOfTInnerKey,
transformedKeySelectorAsString,
inlinedHashCodeComputation,
nested)
{
swingingField = swingingField,
payloadMightBeNull = typeOfTSource.CanContainNull()
};
if (!nested && Config.UseMultiString &&
typeOfTInnerKey.Equals(typeof(string)) &&
keySelector.IsSimpleFieldOrPropertyAccess())
{
var transformedPredicate = Extensions.TransformUnaryFunction <TOuterKey, TSource>(keySelector).Body;
template.transformedKeySelectorAsString = transformedPredicate.ExpressionToCSharp();
template.inlinedHashCodeComputation = "hashCodeVector.col[i]";
var fieldName = ((MemberExpression)keySelector.Body).Member.Name;
template.vectorHashCodeInitialization = $"resultBatch.hash = {Transformer.ColumnFieldPrefix}{fieldName}_col.GetHashCode(batch.bitvector);";
template.swingingHashColumn = true;
}
template.fields = new ColumnarRepresentation(typeOfTSource).AllFields;
expandedCode = template.TransformText();
assemblyReferences = Transformer.AssemblyReferencesNeededFor(typeOfTOuterKey, typeOfTSource, typeOfTInnerKey);
assemblyReferences.Add(typeof(IStreamable <,>).GetTypeInfo().Assembly);
assemblyReferences.Add(Transformer.GeneratedStreamMessageAssembly <TOuterKey, TSource>());
if (nested)
{
assemblyReferences.Add(Transformer.GeneratedStreamMessageAssembly <CompoundGroupKey <TOuterKey, TInnerKey>, TSource>());
assemblyReferences.Add(Transformer.GeneratedMemoryPoolAssembly <CompoundGroupKey <TOuterKey, TInnerKey>, TSource>());
}
else
{
assemblyReferences.Add(Transformer.GeneratedStreamMessageAssembly <TInnerKey, TSource>());
assemblyReferences.Add(Transformer.GeneratedMemoryPoolAssembly <TInnerKey, TSource>());
}
assemblyReferences.AddRange(Transformer.AssemblyReferencesNeededFor(keySelector));
var a = Transformer.CompileSourceCode(expandedCode, assemblyReferences, out errorMessages);
if (typeOfTInnerKey.IsAnonymousTypeName())
{
if (errorMessages == null)
{
errorMessages = string.Empty;
}
errorMessages += "\nCodegen Warning: The inner key type for Group is anonymous, causing the use of Activator.CreateInstance in an inner loop. This will lead to poor performance.\n";
}
generatedClassName = generatedClassName.AddNumberOfNecessaryGenericArguments(typeOfTOuterKey, typeOfTSource, typeOfTInnerKey);
var t = a.GetType(generatedClassName);
t = t.InstantiateAsNecessary(typeOfTOuterKey, typeOfTSource, typeOfTInnerKey);
return(Tuple.Create(t, errorMessages));
}
catch
{
if (Config.CodegenOptions.DontFallBackToRowBasedExecution)
{
throw new InvalidOperationException("Code Generation failed when it wasn't supposed to!");
}
return(Tuple.Create((Type)null, errorMessages));
}
}