public static IReadOnlyDictionary <SelectionSetNode, PSS> Compile(
ISchema schema,
FragmentCollection fragments,
OperationDefinitionNode operation,
IEnumerable <ISelectionSetOptimizer>?optimizers = null)
{
var selectionSets = new Dictionary <SelectionSetNode, PSS>();
void Register(PreparedSelectionSet s) => selectionSets[s.SelectionSet] = s;
SelectionSetNode selectionSet = operation.SelectionSet;
ObjectType typeContext = schema.GetOperationType(operation.Operation);
var root = new PSS(operation.SelectionSet);
Register(root);
var collector = new OperationCompiler(schema, fragments);
collector.Visit(
selectionSet,
typeContext,
new Stack <IObjectField>(),
root,
Register,
new Dictionary <ISelectionNode, SelectionIncludeCondition>(),
optimizers?.ToList() ?? new List <ISelectionSetOptimizer>());
return(selectionSets);
}
private void Visit(
SelectionSetNode selectionSet,
ObjectType typeContext,
Stack <IObjectField> fieldContext,
PSS current,
Action <PSS> register,
IDictionary <ISelectionNode, SelectionIncludeCondition> includeConditionLookup,
List <ISelectionSetOptimizer> optimizers,
bool internalSelection = false)
{
// we first collect the fields that we find in the selection set ...
IDictionary <string, PreparedSelection> fields =
CollectFields(typeContext, selectionSet, includeConditionLookup, internalSelection);
// ... after that is done we will check if there are query optimizer that want
// to provide additional fields.
OptimizeSelectionSet(fieldContext, typeContext, selectionSet, fields, optimizers);
var selections = new List <PreparedSelection>();
var isConditional = false;
foreach (PreparedSelection selection in fields.Values)
{
// we now make the selection read-only and add it to the final selection-set.
selection.MakeReadOnly();
selections.Add(selection);
// if one selection of a selection-set is conditional,
// then the whole set is conditional.
if (!isConditional && (selection.IsConditional || selection.IsInternal))
{
isConditional = true;
}
// if the field of the selection returns a composite type we will traverse
// the child selection-sets as well.
INamedType fieldType = selection.Field.Type.NamedType();
if (fieldType.IsCompositeType())
{
if (selection.SelectionSet is null)
{
// composite fields always have to have a selection-set
// otherwise we need to throw.
throw QueryCompiler_CompositeTypeSelectionSet(selection.Selection);
}
var next = new PSS(selection.SelectionSet);
register(next);
IReadOnlyList <ObjectType> possibleTypes = _schema.GetPossibleTypes(fieldType);
for (var i = 0; i < possibleTypes.Count; i++)
{
// we prepare the field context and check if there are field specific
// optimizers that we might want to include.
fieldContext.Push(selection.Field);
var initialCount = optimizers.Count;
var registered = RegisterOptimizers(optimizers, selection.Field);
Visit(
selection.SelectionSet,
possibleTypes[i],
fieldContext,
next,
register,
includeConditionLookup,
optimizers,
selection.IsInternal);
// lets clean up the context again and move on to the next.
UnregisterOptimizers(optimizers, initialCount, registered);
fieldContext.Pop();
}
}
}
current.AddSelections(
typeContext,
new PreparedSelectionList(selections, isConditional));
}
