errors

var (
	ErrReadOnly                = &Error{"database is readonly: cannot perform operation", leveldb.ErrReadOnly}
	ErrNotFound                = &Error{"object not found", leveldb.ErrNotFound}
	ErrClosed                  = &Error{"database is closed: cannot perform operation", leveldb.ErrClosed}
	ErrIterReleased            = &Error{"iterator released", leveldb.ErrIterReleased}
	ErrSnapshotReleased        = &Error{"snapshot released", leveldb.ErrSnapshotReleased}
	ErrAlreadyExists           = errors.New("object with specified key already exists")
	ErrNotImplemented          = errors.New("this method has not been implemented yet")
	ErrUniqueConstraint        = errors.New("uniqueness constraint has been violated")
	ErrUniqueConstraintChanged = errors.New("cannot modify a unique field")

	ErrInvalidTopic          = errors.New("invalid topic")
	ErrTopicMissingProjectId = &Error{"missing project_id field", ErrInvalidTopic}
	ErrTopicInvalidProjectId = &Error{"cannot parse project_id field", ErrInvalidTopic}
	ErrTopicMissingName      = &Error{"missing name field", ErrInvalidTopic}
	ErrTopicNameTooLong      = &Error{"topic name is too long", ErrInvalidTopic}
	ErrInvalidTopicName      = &Error{"topic name is invalid", ErrInvalidTopic}
	ErrTopicMissingId        = &Error{"missing id field", ErrInvalidTopic}
	ErrTopicInvalidId        = &Error{"cannot parse id field", ErrInvalidTopic}
	ErrTopicInvalidCreated   = &Error{"invalid created field", ErrInvalidTopic}
	ErrTopicInvalidModified  = &Error{"invalid modified field", ErrInvalidTopic}
	ErrUniqueTopicName       = &Error{"topic name already exists in project", ErrInvalidTopic}
	ErrTopicNameChanged      = &Error{"topic name cannot be changed", ErrInvalidTopic}

	ErrInvalidTopicInfo          = errors.New("invalid topic info")
	ErrTopicInfoMissingProjectId = &Error{"missing project_id field", ErrInvalidTopicInfo}
	ErrTopicInfoMissingTopicId   = &Error{"missing topic_id field", ErrInvalidTopicInfo}
	ErrTopicInfoInvalidProjectId = &Error{"cannot parse project_id field", ErrInvalidTopicInfo}
	ErrTopicInfoInvalidTopicId   = &Error{"cannot parse topic_id field", ErrInvalidTopicInfo}

	ErrInvalidGroup          = errors.New("invalid group")
	ErrGroupMissingProjectId = &Error{"missing project_id field", ErrInvalidGroup}
	ErrGroupInvalidProjectId = &Error{"cannot parse project_id field", ErrInvalidGroup}
	ErrGroupMissingId        = &Error{"missing id field", ErrInvalidGroup}
	ErrGroupMissingKeyField  = &Error{"missing one of id or name fields", ErrInvalidGroup}
	ErrGroupInvalidCreated   = &Error{"invalid created field", ErrInvalidGroup}
	ErrGroupInvalidModified  = &Error{"invalid modified field", ErrInvalidGroup}

	ErrInvalidEvent        = errors.New("invalid event")
	ErrEventMissingId      = &Error{"missing id field", ErrInvalidEvent}
	ErrEventMissingTopicId = &Error{"missing topic_id field", ErrInvalidEvent}
	ErrEventInvalidId      = &Error{"invalid id field", ErrInvalidEvent}
	ErrEventInvalidTopicId = &Error{"invalid topic_id field", ErrInvalidEvent}

	ErrInvalidKey   = errors.New("invalid object key")
	ErrKeyWrongSize = &Error{"incorrect key size", ErrInvalidKey}
	ErrKeyNull      = &Error{"no part of the key can be zero-valued", ErrInvalidKey}

	ErrInvalidPage      = errors.New("invalid page token")
	ErrPageTokenExpired = &Error{"next page token has expired", ErrInvalidPage}
	ErrInvalidPageToken = &Error{"invalid next page token field", ErrInvalidPage}
)