package filter import ( "fmt" "github.com/bdlm/log" "github.com/pkg/errors" "github.com/FreifunkBremen/yanic/runtime" ) // factory function for building a filter // may return nil if the filter never applies type factory func(interface{}) (Filter, error) // Filter is a filter instance type Filter interface { Apply(*runtime.Node) *runtime.Node } // Set is a list of configured filters type Set []Filter var filters = make(map[string]factory) // Register registers a new filter func Register(name string, f factory) { if _, ok := filters[name]; ok { log.WithField("filter", name).Panic("filter already registered") } filters[name] = f } // New returns and initializes a set of filters func New(configs map[string]interface{}) (set Set, errs []error) { for name, config := range configs { if config == nil { return } f := filters[name] if f == nil { errs = append(errs, fmt.Errorf("unknown filter: %s", name)) } else if filter, err := f(config); err != nil { errs = append(errs, errors.Wrapf(err, "unable to initialize filter %s", name)) } else if filter != nil { set = append(set, filter) } } return } // Apply applies the filter set to the given node list and returns a new node list func (set Set) Apply(nodesOrigin *runtime.Nodes) *runtime.Nodes { nodes := runtime.NewNodes(&runtime.NodesConfig{}) nodesOrigin.Lock() defer nodesOrigin.Unlock() for _, nodeOrigin := range nodesOrigin.List { //maybe cloning of this object is better? node := nodeOrigin for _, filter := range set { node = filter.Apply(node) if node == nil { break } } if node != nil { nodes.AddNode(node) } } return nodes }