From 49fd47c86313f036da3a9549e7d14def166f4ea7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Behouba=20Manass=C3=A9?= <behouba@gmail.com>
Date: Mon, 30 Sep 2019 19:25:04 +0300
Subject: [PATCH] selectAccountDataByType return ClientEvent pointer instead of
 slice of ClientEvent (#798)
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This pull request is an attempt to fix #773.

Signed-off-by: Kouame Behouba Manassé behouba@gmail.com
---
 .../storage/accounts/account_data_table.go    | 25 ++++++-------------
 clientapi/auth/storage/accounts/storage.go    |  4 +--
 clientapi/routing/room_tagging.go             | 14 +++++------
 syncapi/sync/requestpool.go                   |  4 +--
 4 files changed, 18 insertions(+), 29 deletions(-)

diff --git a/clientapi/auth/storage/accounts/account_data_table.go b/clientapi/auth/storage/accounts/account_data_table.go
index 0d73cb31..0d6ad093 100644
--- a/clientapi/auth/storage/accounts/account_data_table.go
+++ b/clientapi/auth/storage/accounts/account_data_table.go
@@ -120,28 +120,17 @@ func (s *accountDataStatements) selectAccountData(
 
 func (s *accountDataStatements) selectAccountDataByType(
 	ctx context.Context, localpart, roomID, dataType string,
-) (data []gomatrixserverlib.ClientEvent, err error) {
-	data = []gomatrixserverlib.ClientEvent{}
-
+) (data *gomatrixserverlib.ClientEvent, err error) {
 	stmt := s.selectAccountDataByTypeStmt
-	rows, err := stmt.QueryContext(ctx, localpart, roomID, dataType)
-	if err != nil {
+	var content []byte
+
+	if err = stmt.QueryRowContext(ctx, localpart, roomID, dataType).Scan(&content); err != nil {
 		return
 	}
 
-	for rows.Next() {
-		var content []byte
-
-		if err = rows.Scan(&content); err != nil {
-			return
-		}
-
-		ac := gomatrixserverlib.ClientEvent{
-			Type:    dataType,
-			Content: content,
-		}
-
-		data = append(data, ac)
+	data = &gomatrixserverlib.ClientEvent{
+		Type:    dataType,
+		Content: content,
 	}
 
 	return
diff --git a/clientapi/auth/storage/accounts/storage.go b/clientapi/auth/storage/accounts/storage.go
index 41d75daa..020a3837 100644
--- a/clientapi/auth/storage/accounts/storage.go
+++ b/clientapi/auth/storage/accounts/storage.go
@@ -263,11 +263,11 @@ func (d *Database) GetAccountData(ctx context.Context, localpart string) (
 
 // GetAccountDataByType returns account data matching a given
 // localpart, room ID and type.
-// If no account data could be found, returns an empty array
+// If no account data could be found, returns nil
 // Returns an error if there was an issue with the retrieval
 func (d *Database) GetAccountDataByType(
 	ctx context.Context, localpart, roomID, dataType string,
-) (data []gomatrixserverlib.ClientEvent, err error) {
+) (data *gomatrixserverlib.ClientEvent, err error) {
 	return d.accountDatas.selectAccountDataByType(
 		ctx, localpart, roomID, dataType,
 	)
diff --git a/clientapi/routing/room_tagging.go b/clientapi/routing/room_tagging.go
index 6e7324cd..487081c5 100644
--- a/clientapi/routing/room_tagging.go
+++ b/clientapi/routing/room_tagging.go
@@ -59,7 +59,7 @@ func GetTags(
 		return httputil.LogThenError(req, err)
 	}
 
-	if len(data) == 0 {
+	if data == nil {
 		return util.JSONResponse{
 			Code: http.StatusOK,
 			JSON: struct{}{},
@@ -68,7 +68,7 @@ func GetTags(
 
 	return util.JSONResponse{
 		Code: http.StatusOK,
-		JSON: data[0].Content,
+		JSON: data.Content,
 	}
 }
 
@@ -103,8 +103,8 @@ func PutTag(
 	}
 
 	var tagContent gomatrix.TagContent
-	if len(data) > 0 {
-		if err = json.Unmarshal(data[0].Content, &tagContent); err != nil {
+	if data != nil {
+		if err = json.Unmarshal(data.Content, &tagContent); err != nil {
 			return httputil.LogThenError(req, err)
 		}
 	} else {
@@ -155,7 +155,7 @@ func DeleteTag(
 	}
 
 	// If there are no tags in the database, exit
-	if len(data) == 0 {
+	if data == nil {
 		// Spec only defines 200 responses for this endpoint so we don't return anything else.
 		return util.JSONResponse{
 			Code: http.StatusOK,
@@ -164,7 +164,7 @@ func DeleteTag(
 	}
 
 	var tagContent gomatrix.TagContent
-	err = json.Unmarshal(data[0].Content, &tagContent)
+	err = json.Unmarshal(data.Content, &tagContent)
 	if err != nil {
 		return httputil.LogThenError(req, err)
 	}
@@ -204,7 +204,7 @@ func obtainSavedTags(
 	userID string,
 	roomID string,
 	accountDB *accounts.Database,
-) (string, []gomatrixserverlib.ClientEvent, error) {
+) (string, *gomatrixserverlib.ClientEvent, error) {
 	localpart, _, err := gomatrixserverlib.SplitID('@', userID)
 	if err != nil {
 		return "", nil, err
diff --git a/syncapi/sync/requestpool.go b/syncapi/sync/requestpool.go
index 6b95f469..94a36900 100644
--- a/syncapi/sync/requestpool.go
+++ b/syncapi/sync/requestpool.go
@@ -196,13 +196,13 @@ func (rp *RequestPool) appendAccountData(
 		events := []gomatrixserverlib.ClientEvent{}
 		// Request the missing data from the database
 		for _, dataType := range dataTypes {
-			evs, err := rp.accountDB.GetAccountDataByType(
+			event, err := rp.accountDB.GetAccountDataByType(
 				req.ctx, localpart, roomID, dataType,
 			)
 			if err != nil {
 				return nil, err
 			}
-			events = append(events, evs...)
+			events = append(events, *event)
 		}
 
 		// Append the data to the response