From e0df08f4f125d73c59e5fcf07327416b6ec63fbf Mon Sep 17 00:00:00 2001
From: Mark Haines <mjark@negativecurvature.net>
Date: Tue, 7 Feb 2017 14:36:09 +0000
Subject: [PATCH] Rework the assign.*NID again

---
 .../dendrite/roomserver/storage/sql.go        | 12 ----------
 .../dendrite/roomserver/storage/storage.go    | 24 ++++++++++++-------
 2 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/src/github.com/matrix-org/dendrite/roomserver/storage/sql.go b/src/github.com/matrix-org/dendrite/roomserver/storage/sql.go
index fa8f9d3d5..410b294b7 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/storage/sql.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/storage/sql.go
@@ -182,10 +182,6 @@ func (s *statements) insertEventTypeNID(eventType string) (eventTypeNID int64, e
 
 func (s *statements) selectEventTypeNID(eventType string) (eventTypeNID int64, err error) {
 	err = s.selectEventTypeNIDStmt.QueryRow(eventType).Scan(&eventTypeNID)
-	if err == sql.ErrNoRows {
-		eventTypeNID = 0
-		err = nil
-	}
 	return
 }
 
@@ -241,10 +237,6 @@ func (s *statements) insertEventStateKeyNID(eventStateKey string) (eventStateKey
 
 func (s *statements) selectEventStateKeyNID(eventStateKey string) (eventStateKeyNID int64, err error) {
 	err = s.selectEventStateKeyNIDStmt.QueryRow(eventStateKey).Scan(&eventStateKeyNID)
-	if err == sql.ErrNoRows {
-		eventStateKeyNID = 0
-		err = nil
-	}
 	return
 }
 
@@ -289,10 +281,6 @@ func (s *statements) insertRoomNID(roomID string) (roomNID int64, err error) {
 
 func (s *statements) selectRoomNID(roomID string) (roomNID int64, err error) {
 	err = s.selectRoomNIDStmt.QueryRow(roomID).Scan(&roomNID)
-	if err == sql.ErrNoRows {
-		roomNID = 0
-		err = nil
-	}
 	return
 }
 
diff --git a/src/github.com/matrix-org/dendrite/roomserver/storage/storage.go b/src/github.com/matrix-org/dendrite/roomserver/storage/storage.go
index 41fa25eab..1d6d7a327 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/storage/storage.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/storage/storage.go
@@ -78,34 +78,40 @@ func (d *Database) StoreEvent(event gomatrixserverlib.Event) error {
 }
 
 func (d *Database) assignRoomNID(roomID string) (int64, error) {
+	// Check if we already have a numeric ID in the database.
 	roomNID, err := d.statements.selectRoomNID(roomID)
+	if err == sql.ErrNoRows {
+		// We don't have a numeric ID so insert one into the database.
+		return d.statements.insertRoomNID(roomID)
+	}
 	if err != nil {
 		return 0, err
 	}
-	if roomNID == 0 {
-		return d.statements.insertRoomNID(roomID)
-	}
 	return roomNID, nil
 }
 
 func (d *Database) assignEventTypeNID(eventType string) (int64, error) {
+	// Check if we already have a numeric ID in the database.
 	eventTypeNID, err := d.statements.selectEventTypeNID(eventType)
+	if err == sql.ErrNoRows {
+		// We don't have a numeric ID so insert one into the database.
+		return d.statements.insertEventTypeNID(eventType)
+	}
 	if err != nil {
 		return 0, err
 	}
-	if eventTypeNID == 0 {
-		return d.statements.insertEventTypeNID(eventType)
-	}
 	return eventTypeNID, nil
 }
 
 func (d *Database) assignStateKeyNID(eventStateKey string) (int64, error) {
+	// Check if we already have a numeric ID in the database.
 	eventStateKeyNID, err := d.statements.selectEventStateKeyNID(eventStateKey)
+	if err == sql.ErrNoRows {
+		// We don't have a numeric ID so insert one into the database.
+		return d.statements.insertEventStateKeyNID(eventStateKey)
+	}
 	if err != nil {
 		return 0, err
 	}
-	if eventStateKeyNID == 0 {
-		return d.statements.insertEventStateKeyNID(eventStateKey)
-	}
 	return eventStateKeyNID, nil
 }