NewCannotWriteToPermissionError constructs a new error for attempting to write to a permission.

NewCaveatNotFoundError constructs a new caveat not found error.

NewInvalidSubjectTypeError constructs a new error for attempting to write an invalid subject type.

ValidateOneRelationship validates a single relationship for CREATE/TOUCH or DELETE.

ValidateRelationshipsForCreateOrTouch performs validation on the given relationships to be written, ensuring that they can be applied against the datastore.

ValidateRelationshipUpdates performs validation on the given relationship updates, ensuring that they can be applied against the datastore.

ValidateRelationshipForCreateOrTouch indicates that the validation should occur for a CREATE or TOUCH operation.

ValidateRelationshipForDeletion indicates that the validation should occur for a DELETE operation.

CannotWriteToPermissionError indicates that a write was attempted on a permission.

CaveatNotFoundError indicates that a caveat referenced in a relationship update was not found.

InvalidSubjectTypeError indicates that a write was attempted with a subject type which is not allowed on relation.

ValidationRelationshipRule is the rule to use for the validation.