From fea8b5787a70f6afb235158030529ad23116632e Mon Sep 17 00:00:00 2001
From: Devon Hudson <devonhudson@librem.one>
Date: Mon, 5 Dec 2022 13:14:58 -0700
Subject: [PATCH] Mark the possible separation line for mailservers

---
 federationapi/api/api.go              | 17 ++++++++++++-----
 federationapi/routing/asyncevents.go  |  1 +
 federationapi/routing/forwardasync.go |  1 +
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/federationapi/api/api.go b/federationapi/api/api.go
index 2b29751ac..85fb09875 100644
--- a/federationapi/api/api.go
+++ b/federationapi/api/api.go
@@ -18,6 +18,7 @@ type FederationInternalAPI interface {
 	gomatrixserverlib.KeyDatabase
 	ClientFederationAPI
 	RoomserverFederationAPI
+	MailserverAPI
 
 	QueryServerKeys(ctx context.Context, request *QueryServerKeysRequest, response *QueryServerKeysResponse) error
 	LookupServerKeys(ctx context.Context, s gomatrixserverlib.ServerName, keyRequests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp) ([]gomatrixserverlib.ServerKeys, error)
@@ -30,21 +31,27 @@ type FederationInternalAPI interface {
 		request *PerformBroadcastEDURequest,
 		response *PerformBroadcastEDUResponse,
 	) error
+	PerformWakeupServers(
+		ctx context.Context,
+		request *PerformWakeupServersRequest,
+		response *PerformWakeupServersResponse,
+	) error
+}
+
+type MailserverAPI interface {
+	// Store async transactions for forwarding to the destination at a later time.
 	PerformStoreAsync(
 		ctx context.Context,
 		request *PerformStoreAsyncRequest,
 		response *PerformStoreAsyncResponse,
 	) error
+
+	// Obtain the oldest stored transaction for the specified userID.
 	QueryAsyncTransactions(
 		ctx context.Context,
 		request *QueryAsyncTransactionsRequest,
 		response *QueryAsyncTransactionsResponse,
 	) error
-	PerformWakeupServers(
-		ctx context.Context,
-		request *PerformWakeupServersRequest,
-		response *PerformWakeupServersResponse,
-	) error
 }
 
 type ClientFederationAPI interface {
diff --git a/federationapi/routing/asyncevents.go b/federationapi/routing/asyncevents.go
index 9a35e6805..c8cbf1dd9 100644
--- a/federationapi/routing/asyncevents.go
+++ b/federationapi/routing/asyncevents.go
@@ -14,6 +14,7 @@ type AsyncEventsResponse struct {
 }
 
 // GetAsyncEvents implements /_matrix/federation/v1/async_events/{userID}
+// This endpoint can be extracted into a separate mailserver service.
 func GetAsyncEvents(
 	httpReq *http.Request,
 	fedReq *gomatrixserverlib.FederationRequest,
diff --git a/federationapi/routing/forwardasync.go b/federationapi/routing/forwardasync.go
index f290c8313..9d7089ac4 100644
--- a/federationapi/routing/forwardasync.go
+++ b/federationapi/routing/forwardasync.go
@@ -11,6 +11,7 @@ import (
 )
 
 // ForwardAsync implements /_matrix/federation/v1/forward_async/{txnID}/{userID}
+// This endpoint can be extracted into a separate mailserver service.
 func ForwardAsync(
 	httpReq *http.Request,
 	fedReq *gomatrixserverlib.FederationRequest,