restructure waitforconnections into a callback registration

connect/connect.go

@@ -7,6 +7,7 @@
 package connect
 
 import (
+	"github.com/pkg/errors"
 	jww "github.com/spf13/jwalterweatherman"
 	"gitlab.com/elixxir/client/auth"
 	"gitlab.com/elixxir/client/catalog"
@@ -88,7 +89,11 @@ func Connect(recipient contact.Contact, myId *id.ID, rng *fastRNG.StreamGenerato
 	}
 
 	// Build callback for E2E negotiation
-	callback := getAuthCallback()
+	signalChannel := make(chan Connection, 1)
+	cb := func(connection Connection) {
+		signalChannel <- connection
+	}
+	callback := getAuthCallback(cb, e2eHandler, p)
 
 	// Build auth object for E2E negotiation
 	authState, err := auth.NewState(kv, net, e2eHandler,
@@ -105,22 +110,22 @@ func Connect(recipient contact.Contact, myId *id.ID, rng *fastRNG.StreamGenerato
 
 	// Block waiting for auth to confirm
 	jww.DEBUG.Printf("Connection waiting for auth request for %s to be confirmed...", recipient.ID.String())
-	<-callback.confirmPartner
-	jww.DEBUG.Printf("Connection auth request for %s confirmed", recipient.ID.String())
+	newConnection := <-signalChannel
 
-	// After confirmation, get the new partner
-	newPartner, err := e2eHandler.GetPartner(recipient.ID)
-	if err != nil {
-		return nil, err
+	// Verify the Connection is complete
+	if newConnection == nil {
+		return nil, errors.Errorf("Unable to complete connection with partner %s", recipient.ID.String())
 	}
+	jww.DEBUG.Printf("Connection auth request for %s confirmed", recipient.ID.String())
 
-	return BuildConnection(newPartner, e2eHandler, p), nil
+	return newConnection, nil
 }
 
-// WaitForConnections assembles a Connection object on the reception-side
-// when an incoming request for an E2E partnership with a partner.Manager is confirmed.
-func WaitForConnections(myId *id.ID, rng *fastRNG.StreamGenerator,
-	grp *cyclic.Group, net cmix.Client, p Params) (Connection, error) {
+// RegisterConnectionCallback assembles a Connection object on the reception-side
+// and feeds it into the given Callback whenever an incoming request
+// for an E2E partnership with a partner.Manager is confirmed.
+func RegisterConnectionCallback(cb Callback, myId *id.ID, rng *fastRNG.StreamGenerator,
+	grp *cyclic.Group, net cmix.Client, p Params) error {
 
 	// Build an ephemeral KV
 	kv := versioned.NewKV(ekv.MakeMemstore())
@@ -128,32 +133,16 @@ func WaitForConnections(myId *id.ID, rng *fastRNG.StreamGenerator,
 	// Build E2e handler
 	e2eHandler, err := clientE2e.Load(kv, net, myId, grp, rng, p.event)
 	if err != nil {
-		return nil, err
+		return err
 	}
 
 	// Build callback for E2E negotiation
-	callback := getAuthCallback()
+	callback := getAuthCallback(cb, e2eHandler, p)
 
 	// Build auth object for E2E negotiation
 	_, err = auth.NewState(kv, net, e2eHandler,
 		rng, p.event, p.auth, callback, nil)
-	if err != nil {
-		return nil, err
-	}
-
-	// Block waiting for incoming auth request
-	jww.DEBUG.Printf("Connection waiting for auth request to be received...")
-	newPartnerId := <-callback.confirmPartner
-	jww.DEBUG.Printf("Connection auth request for %s confirmed", newPartnerId.String())
-
-	// After confirmation, get the new partner
-	newPartner, err := e2eHandler.GetPartner(newPartnerId)
-	if err != nil {
-		return nil, err
-	}
-
-	// Return the new Connection object
-	return BuildConnection(newPartner, e2eHandler, p), nil
+	return err
 }
 
 // BuildConnection assembles a Connection object
@@ -198,26 +187,46 @@ func (h *handler) Unregister(listenerID receive.ListenerID) {
 // and for dynamically building new Connection objects when an auth Request is received.
 type authCallback struct {
 	// Used for signaling confirmation of E2E partnership
-	confirmPartner chan *id.ID
+	connectionCallback Callback
+
+	// Used for building new Connection objects
+	connectionE2e    clientE2e.Handler
+	connectionParams Params
 }
 
+//
+type Callback func(connection Connection)
+
 // getAuthCallback returns a callback interface to be passed into the creation of an auth.State object.
-func getAuthCallback() authCallback {
+func getAuthCallback(cb Callback, e2e clientE2e.Handler, params Params) authCallback {
 	return authCallback{
-		confirmPartner: make(chan *id.ID, 10),
+		connectionCallback: cb,
+		connectionE2e:      e2e,
+		connectionParams:   params,
 	}
 }
 
 // Confirm will be called when an auth Confirm message is processed
-func (c authCallback) Confirm(requestor contact.Contact, receptionID receptionID.EphemeralIdentity, round rounds.Round) {
-	// Signal to a listening thread that the partnership is confirmed
-	c.confirmPartner <- requestor.ID
+func (a authCallback) Confirm(requestor contact.Contact, receptionID receptionID.EphemeralIdentity, round rounds.Round) {
+	jww.DEBUG.Printf("Connection auth request for %s confirmed", requestor.ID.String())
+
+	// After confirmation, get the new partner
+	newPartner, err := a.connectionE2e.GetPartner(requestor.ID)
+	if err != nil {
+		jww.ERROR.Printf("Unable to build connection with partner %s: %+v", requestor.ID, err)
+		// Send a nil connection to avoid hold-ups down the line
+		a.connectionCallback(nil)
+		return
+	}
+
+	// Return the new Connection object
+	a.connectionCallback(BuildConnection(newPartner, a.connectionE2e, a.connectionParams))
 }
 
 // Request will be called when an auth Request message is processed
-func (c authCallback) Request(requestor contact.Contact, receptionID receptionID.EphemeralIdentity, round rounds.Round) {
+func (a authCallback) Request(requestor contact.Contact, receptionID receptionID.EphemeralIdentity, round rounds.Round) {
 }
 
 // Reset will be called when an auth Reset operation occurs
-func (c authCallback) Reset(requestor contact.Contact, receptionID receptionID.EphemeralIdentity, round rounds.Round) {
+func (a authCallback) Reset(requestor contact.Contact, receptionID receptionID.EphemeralIdentity, round rounds.Round) {
 }