table: Add identity, static and regexp table modules

internal/table/static.go

@@ -0,0 +1,50 @@
+package table
+
+import (
+	"github.com/foxcpp/maddy/internal/config"
+	"github.com/foxcpp/maddy/internal/module"
+)
+
+type Static struct {
+	modName  string
+	instName string
+
+	m map[string]string
+}
+
+func NewStatic(modName, instName string, _, _ []string) (module.Module, error) {
+	return &Static{
+		modName:  modName,
+		instName: instName,
+		m:        map[string]string{},
+	}, nil
+}
+
+func (s *Static) Init(cfg *config.Map) error {
+	cfg.Callback("entry", func(m *config.Map, node config.Node) error {
+		if len(node.Args) != 2 {
+			return config.NodeErr(node, "expected exactly two arguments")
+		}
+		s.m[node.Args[0]] = node.Args[1]
+		return nil
+	})
+	_, err := cfg.Process()
+	return err
+}
+
+func (s *Static) Name() string {
+	return s.modName
+}
+
+func (s *Static) InstanceName() string {
+	return s.modName
+}
+
+func (s *Static) Lookup(key string) (string, bool, error) {
+	val, ok := s.m[key]
+	return val, ok, nil
+}
+
+func init() {
+	module.Register("static", NewStatic)
+}