From 1772d830da60ddfd16be65001fb967faa15cc654 Mon Sep 17 00:00:00 2001
From: Cnly <minecnly@gmail.com>
Date: Thu, 1 Aug 2019 11:03:24 +0800
Subject: [PATCH] Variable and type clarifications

Signed-off-by: Alex Chen <minecnly@gmail.com>
---
 roomserver/storage/redactions_table.go |  8 ++++++--
 roomserver/storage/storage.go          | 14 +++++++-------
 syncapi/storage/syncserver.go          |  4 ++--
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/roomserver/storage/redactions_table.go b/roomserver/storage/redactions_table.go
index f9f88ebf3..f09c13fe0 100644
--- a/roomserver/storage/redactions_table.go
+++ b/roomserver/storage/redactions_table.go
@@ -56,6 +56,9 @@ type redactionStatements struct {
 	bulkUpdateValidationStatusStmt *sql.Stmt
 }
 
+// redactedToRedactionMap is a map in the form map[redactedEventID]redactionEventNID.
+type redactedToRedactionMap map[string]types.EventNID
+
 func (s *redactionStatements) prepare(db *sql.DB) (err error) {
 	_, err = db.Exec(redactionsSchema)
 	if err != nil {
@@ -81,13 +84,14 @@ func (s *redactionStatements) insertRedaction(
 	return err
 }
 
+// bulkSelectRedaction returns the redactions for the given event IDs.
+// Return values validated and unvalidated are both map[redactedEventID]redactedByNID.
 func (s *redactionStatements) bulkSelectRedaction(
 	ctx context.Context,
 	txn *sql.Tx,
 	eventIDs []string,
 ) (
-	validated map[string]types.EventNID,
-	unvalidated map[string]types.EventNID,
+	validated, unvalidated redactedToRedactionMap,
 	err error,
 ) {
 	stmt := common.TxStmt(txn, s.bulkSelectRedactionStmt)
diff --git a/roomserver/storage/storage.go b/roomserver/storage/storage.go
index bc0f9504f..28bb27863 100644
--- a/roomserver/storage/storage.go
+++ b/roomserver/storage/storage.go
@@ -295,7 +295,7 @@ func (d *Database) applyRedactions(
 	}
 
 	if len(unvalidatedRedactions) != 0 {
-		var newlyValidated map[string]types.EventNID
+		var newlyValidated redactedToRedactionMap
 		if newlyValidated, err = d.validateRedactions(
 			ctx, unvalidatedRedactions, redactionNIDToEvent, eventIDToEventPointer,
 		); err != nil {
@@ -325,7 +325,7 @@ func (d *Database) applyRedactions(
 
 func (d *Database) fetchRedactionEvents(
 	ctx context.Context,
-	validatedRedactions, unvalidatedRedactions map[string]types.EventNID,
+	validatedRedactions, unvalidatedRedactions redactedToRedactionMap,
 ) (redactionNIDToEvent map[types.EventNID]*gomatrixserverlib.Event, err error) {
 	redactionEventsToFetch := make([]types.EventNID, 0, len(validatedRedactions)+len(unvalidatedRedactions))
 	for _, nid := range validatedRedactions {
@@ -354,15 +354,15 @@ func (d *Database) fetchRedactionEvents(
 
 func (d *Database) validateRedactions(
 	ctx context.Context,
-	unvalidatedRedactions map[string]types.EventNID,
+	unvalidatedRedactions redactedToRedactionMap,
 	redactionNIDToEvent map[types.EventNID]*gomatrixserverlib.Event,
-	eventIDToEvent map[string]*gomatrixserverlib.Event,
-) (validatedRedactions map[string]types.EventNID, err error) {
-	validatedRedactions = make(map[string]types.EventNID, len(unvalidatedRedactions))
+	redactedIDToEvent map[string]*gomatrixserverlib.Event,
+) (validatedRedactions redactedToRedactionMap, err error) {
+	validatedRedactions = make(redactedToRedactionMap, len(unvalidatedRedactions))
 
 	for redactedEventID, redactedByNID := range unvalidatedRedactions {
 		badEvents, needPowerLevelCheck, validationErr := common.ValidateRedaction(
-			eventIDToEvent[redactedEventID], redactionNIDToEvent[redactedByNID],
+			redactedIDToEvent[redactedEventID], redactionNIDToEvent[redactedByNID],
 		)
 		if validationErr != nil {
 			return nil, validationErr
diff --git a/syncapi/storage/syncserver.go b/syncapi/storage/syncserver.go
index 88beeef91..96001e63a 100644
--- a/syncapi/storage/syncserver.go
+++ b/syncapi/storage/syncserver.go
@@ -982,13 +982,13 @@ func (d *SyncServerDatasource) validateRedactions(
 	txn *sql.Tx,
 	unvalidatedRedactions redactedToRedactionMap,
 	redactionIDToEvent map[string]*gomatrixserverlib.Event,
-	eventIDToEvent map[string]*gomatrixserverlib.Event,
+	redactedIDToEvent map[string]*gomatrixserverlib.Event,
 ) (validatedRedactions redactedToRedactionMap, err error) {
 	validatedRedactions = make(redactedToRedactionMap, len(unvalidatedRedactions))
 
 	for redactedEventID, redactedByID := range unvalidatedRedactions {
 		badEvents, needPowerLevelCheck, validationErr := common.ValidateRedaction(
-			eventIDToEvent[redactedEventID], redactionIDToEvent[redactedByID],
+			redactedIDToEvent[redactedEventID], redactionIDToEvent[redactedByID],
 		)
 		if validationErr != nil {
 			return nil, validationErr