/**
* Implements the instructions for completeValue as defined in the
* "Field entries" section of the spec.
*
* If the field type is Non-Null, then this recursively completes the value
* for the inner type. It throws a field error if that completion returns null,
* as per the "Nullability" section of the spec.
*
* If the field type is a List, then this recursively completes the value
* for the inner type on each item in the list.
*
* If the field type is a Scalar or Enum, ensures the completed value is a legal
* value of the type by calling the `serialize` method of GraphQL type
* definition.
*
* Otherwise, the field type expects a sub-selection set, and will complete the
* value by evaluating all sub-selections.
*/
private static function completeValue(ExecutionContext $exeContext, Type $returnType, $fieldASTs, ResolveInfo $info, &$result)
{
// If field type is NonNull, complete for inner type, and throw field error
// if result is null.
if ($returnType instanceof NonNull) {
$completed = self::completeValue($exeContext, $returnType->getWrappedType(), $fieldASTs, $info, $result);
if ($completed === null) {
throw new Error('Cannot return null for non-nullable type.', $fieldASTs instanceof \ArrayObject ? $fieldASTs->getArrayCopy() : $fieldASTs);
}
return $completed;
}
// If result is null-like, return null.
if (null === $result) {
return null;
}
// If field type is Scalar or Enum, serialize to a valid value, returning
// null if serialization is not possible.
if ($returnType instanceof ScalarType || $returnType instanceof EnumType) {
return $returnType->serialize($result);
}
// If field type is List, and return type is Composite - complete by executing these fields with list value as parameter
if ($returnType instanceof ListOfType) {
$itemType = $returnType->getWrappedType();
Utils::invariant(is_array($result) || $result instanceof \Traversable, 'User Error: expected iterable, but did not find one.');
// For Object[]:
// Allow all object fields to process list value in it's `map` callback:
if ($itemType instanceof ObjectType) {
// Filter out nulls (as `map` doesn't expect it):
$list = [];
foreach ($result as $index => $item) {
if (null !== $item) {
$list[] = $item;
}
}
$subFieldASTs = self::collectSubFields($exeContext, $itemType, $fieldASTs);
$mapped = self::executeFields($exeContext, $itemType, $list, $subFieldASTs);
$i = 0;
$completed = [];
foreach ($result as $index => $item) {
if (null === $item) {
// Complete nulls separately
$completed[] = self::completeValueCatchingError($exeContext, $itemType, $fieldASTs, $info, $item);
} else {
// Assuming same order of mapped values
$completed[] = $mapped[$i++];
}
}
return $completed;
} else {
if ($itemType instanceof AbstractType) {
// Values sharded by ObjectType
$listPerObjectType = [];
// Helper structures to restore ordering after resolve calls
$resultTypeMap = [];
$typeNameMap = [];
$cursors = [];
$copied = [];
foreach ($result as $index => $item) {
$copied[$index] = $item;
if (null !== $item) {
$objectType = $itemType->getObjectType($item, $info);
if ($objectType && !$itemType->isPossibleType($objectType)) {
$exeContext->addError(new Error("Runtime Object type \"{$objectType}\" is not a possible type for \"{$itemType}\"."));
$copied[$index] = null;
} else {
$listPerObjectType[$objectType->name][] = $item;
$resultTypeMap[$index] = $objectType->name;
$typeNameMap[$objectType->name] = $objectType;
}
}
}
$mapped = [];
foreach ($listPerObjectType as $typeName => $list) {
$objectType = $typeNameMap[$typeName];
$subFieldASTs = self::collectSubFields($exeContext, $objectType, $fieldASTs);
$mapped[$typeName] = self::executeFields($exeContext, $objectType, $list, $subFieldASTs);
$cursors[$typeName] = 0;
}
// Restore order:
$completed = [];
foreach ($copied as $index => $item) {
if (null === $item) {
// Complete nulls separately
$completed[] = self::completeValueCatchingError($exeContext, $itemType, $fieldASTs, $info, $item);
} else {
$typeName = $resultTypeMap[$index];
$completed[] = $mapped[$typeName][$cursors[$typeName]++];
}
}
return $completed;
} else {
// For simple lists:
$tmp = [];
foreach ($result as $item) {
$tmp[] = self::completeValueCatchingError($exeContext, $itemType, $fieldASTs, $info, $item);
}
return $tmp;
}
}
}
if ($returnType instanceof ObjectType) {
$objectType = $returnType;
} else {
if ($returnType instanceof AbstractType) {
$objectType = $returnType->getObjectType($result, $info);
if ($objectType && !$returnType->isPossibleType($objectType)) {
throw new Error("Runtime Object type \"{$objectType}\" is not a possible type for \"{$returnType}\".");
}
} else {
$objectType = null;
}
}
if (!$objectType) {
return null;
}
// If there is an isTypeOf predicate function, call it with the
// current result. If isTypeOf returns false, then raise an error rather
// than continuing execution.
if (false === $objectType->isTypeOf($result, $info)) {
throw new Error("Expected value of type {$objectType} but got: {$result}.", $fieldASTs);
}
// Collect sub-fields to execute to complete this value.
$subFieldASTs = self::collectSubFields($exeContext, $objectType, $fieldASTs);
$executed = self::executeFields($exeContext, $objectType, [$result], $subFieldASTs);
return isset($executed[0]) ? $executed[0] : null;
}