core: Controller has field to persist server state

Also added ServerBlockHostIndex

config/config.go

@@ -46,8 +46,9 @@ func Load(filename string, input io.Reader) (Group, error) {
 	// executing the directives that were parsed.
 	for i, sb := range serverBlocks {
 		onces := makeOnces()
+		storages := makeStorages()
 
-		for _, addr := range sb.Addresses {
+		for j, addr := range sb.Addresses {
 			config := server.Config{
 				Host:       addr.Host,
 				Port:       addr.Port,
@@ -75,8 +76,10 @@ func Load(filename string, input io.Reader) (Group, error) {
 							})
 							return err
 						},
-						ServerBlockIndex: i,
+						ServerBlockIndex:     i,
-						ServerBlockHosts: sb.HostList(),
+						ServerBlockHostIndex: j,
+						ServerBlockHosts:     sb.HostList(),
+						ServerBlockStorage:   storages[dir.name],
 					}
 
 					midware, err := dir.setup(controller)
@@ -121,6 +124,18 @@ func makeOnces() map[string]*sync.Once {
 	return onces
 }
 
+// makeStorages makes a map of directive name to interface{}
+// so that directives' setup functions can persist state
+// between different hosts on the same server block during the
+// setup phase.
+func makeStorages() map[string]interface{} {
+	storages := make(map[string]interface{})
+	for _, dir := range directiveOrder {
+		storages[dir.name] = nil
+	}
+	return storages
+}
+
 // arrangeBindings groups configurations by their bind address. For example,
 // a server that should listen on localhost and another on 127.0.0.1 will
 // be grouped into the same address: 127.0.0.1. It will return an error

config/setup/controller.go

@@ -29,17 +29,29 @@ type Controller struct {
 	// server block as it appeared in the input.
 	ServerBlockIndex int
 
+	// ServerBlockHostIndex is the 0-based index of this
+	// host as it appeared in the input at the head of the
+	// server block.
+	ServerBlockHostIndex int
+
 	// ServerBlockHosts is a list of hosts that are
 	// associated with this server block. All these
 	// hosts, consequently, share the same tokens.
 	ServerBlockHosts []string
+
+	// ServerBlockStorage is used by a directive's
+	// setup function to persist state between all
+	// the hosts on a server block.
+	ServerBlockStorage interface{}
 }
 
 // NewTestController creates a new *Controller for
-// the input specified, with a filename of "Testfile"
+// the input specified, with a filename of "Testfile".
+// The Config is bare, consisting only of a Root of cwd.
 //
 // Used primarily for testing but needs to be exported so
-// add-ons can use this as a convenience.
+// add-ons can use this as a convenience. Does not initialize
+// the server-block-related fields.
 func NewTestController(input string) *Controller {
 	return &Controller{
 		Config: &server.Config{