From 47c1ef2b49e1c09432f0b251d4a7e81b1f217094 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Tue, 17 Mar 2020 12:26:56 +0000
Subject: [PATCH] Reduce cyclomatic complexity

---
 roomserver/storage/postgres/storage.go | 36 +++++++++++++++++---------
 roomserver/storage/sqlite3/storage.go  | 36 +++++++++++++++++---------
 2 files changed, 48 insertions(+), 24 deletions(-)

diff --git a/roomserver/storage/postgres/storage.go b/roomserver/storage/postgres/storage.go
index 91fe9bdfd..46b4f4d0b 100644
--- a/roomserver/storage/postgres/storage.go
+++ b/roomserver/storage/postgres/storage.go
@@ -77,18 +77,9 @@ func (d *Database) StoreEvent(
 	// Note that the below logic depends on the m.room.create event being the
 	// first event that is persisted to the database when creating or joining a
 	// room.
-	roomVersion := roomserverVersion.DefaultRoomVersion()
-	// Look for m.room.create events.
-	if event.Type() == gomatrixserverlib.MRoomCreate {
-		var createContent gomatrixserverlib.CreateContent
-		// The m.room.create event contains an optional "room_version" key in
-		// the event content, so we need to unmarshal that first.
-		if err = json.Unmarshal(event.Content(), &createContent); err == nil {
-			if createContent.RoomVersion != nil {
-				// A room version was specified in the event content.
-				roomVersion = *createContent.RoomVersion
-			}
-		}
+	var roomVersion gomatrixserverlib.RoomVersion
+	if roomVersion, err = extractRoomVersionFromCreateEvent(event); err != nil {
+		return 0, types.StateAtEvent{}, err
 	}
 
 	if roomNID, err = d.assignRoomNID(ctx, nil, event.RoomID(), roomVersion); err != nil {
@@ -143,6 +134,27 @@ func (d *Database) StoreEvent(
 	}, nil
 }
 
+func extractRoomVersionFromCreateEvent(event gomatrixserverlib.Event) (
+	roomVersion gomatrixserverlib.RoomVersion, err error,
+) {
+	// Look for m.room.create events.
+	if event.Type() != gomatrixserverlib.MRoomCreate {
+		return
+	}
+	roomVersion = roomserverVersion.DefaultRoomVersion()
+	var createContent gomatrixserverlib.CreateContent
+	// The m.room.create event contains an optional "room_version" key in
+	// the event content, so we need to unmarshal that first.
+	if err = json.Unmarshal(event.Content(), &createContent); err != nil {
+		return
+	}
+	// A room version was specified in the event content?
+	if createContent.RoomVersion != nil {
+		roomVersion = *createContent.RoomVersion
+	}
+	return
+}
+
 func (d *Database) assignRoomNID(
 	ctx context.Context, txn *sql.Tx,
 	roomID string, roomVersion gomatrixserverlib.RoomVersion,
diff --git a/roomserver/storage/sqlite3/storage.go b/roomserver/storage/sqlite3/storage.go
index 2f831a450..32ddceb37 100644
--- a/roomserver/storage/sqlite3/storage.go
+++ b/roomserver/storage/sqlite3/storage.go
@@ -99,18 +99,9 @@ func (d *Database) StoreEvent(
 		// Note that the below logic depends on the m.room.create event being the
 		// first event that is persisted to the database when creating or joining a
 		// room.
-		roomVersion := roomserverVersion.DefaultRoomVersion()
-		// Look for m.room.create events.
-		if event.Type() == gomatrixserverlib.MRoomCreate {
-			var createContent gomatrixserverlib.CreateContent
-			// The m.room.create event contains an optional "room_version" key in
-			// the event content, so we need to unmarshal that first.
-			if err = json.Unmarshal(event.Content(), &createContent); err == nil {
-				if createContent.RoomVersion != nil {
-					// A room version was specified in the event content.
-					roomVersion = *createContent.RoomVersion
-				}
-			}
+		var roomVersion gomatrixserverlib.RoomVersion
+		if roomVersion, err = extractRoomVersionFromCreateEvent(event); err != nil {
+			return err
 		}
 
 		if roomNID, err = d.assignRoomNID(ctx, txn, event.RoomID(), roomVersion); err != nil {
@@ -172,6 +163,27 @@ func (d *Database) StoreEvent(
 	}, nil
 }
 
+func extractRoomVersionFromCreateEvent(event gomatrixserverlib.Event) (
+	roomVersion gomatrixserverlib.RoomVersion, err error,
+) {
+	// Look for m.room.create events.
+	if event.Type() != gomatrixserverlib.MRoomCreate {
+		return
+	}
+	roomVersion = roomserverVersion.DefaultRoomVersion()
+	var createContent gomatrixserverlib.CreateContent
+	// The m.room.create event contains an optional "room_version" key in
+	// the event content, so we need to unmarshal that first.
+	if err = json.Unmarshal(event.Content(), &createContent); err != nil {
+		return
+	}
+	// A room version was specified in the event content?
+	if createContent.RoomVersion != nil {
+		roomVersion = *createContent.RoomVersion
+	}
+	return
+}
+
 func (d *Database) assignRoomNID(
 	ctx context.Context, txn *sql.Tx,
 	roomID string, roomVersion gomatrixserverlib.RoomVersion,