Cache GPG keys, emails and users when list commits (#34086)

When list commits, some of the commits authors are the same at many
situations. But current logic will always fetch the same GPG keys from
database. This PR will cache the GPG keys, emails and users for the
context so that reducing the database queries.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/asymkey/gpg_key.go

@@ -240,3 +240,10 @@ func DeleteGPGKey(ctx context.Context, doer *user_model.User, id int64) (err err
 
 	return committer.Commit()
 }
+
+func FindGPGKeyWithSubKeys(ctx context.Context, keyID string) ([]*GPGKey, error) {
+	return db.Find[GPGKey](ctx, FindGPGKeyOptions{
+		KeyID:          keyID,
+		IncludeSubKeys: true,
+	})
+}

models/user/user.go

@@ -1187,29 +1187,28 @@ func GetUsersByEmails(ctx context.Context, emails []string) (map[string]*User, e
 	for _, email := range emailAddresses {
 		userIDs.Add(email.UID)
 	}
-	users, err := GetUsersMapByIDs(ctx, userIDs.Values())
-	if err != nil {
-		return nil, err
-	}
-
 	results := make(map[string]*User, len(emails))
-	for _, email := range emailAddresses {
-		user := users[email.UID]
-		if user != nil {
-			if user.KeepEmailPrivate {
-				results[user.LowerName+"@"+setting.Service.NoReplyAddress] = user
-			} else {
-				results[email.Email] = user
+
+	if len(userIDs) > 0 {
+		users, err := GetUsersMapByIDs(ctx, userIDs.Values())
+		if err != nil {
+			return nil, err
+		}
+
+		for _, email := range emailAddresses {
+			user := users[email.UID]
+			if user != nil {
+				results[user.GetEmail()] = user
 			}
 		}
 	}
 
-	users = make(map[int64]*User, len(needCheckUserNames))
+	users := make(map[int64]*User, len(needCheckUserNames))
 	if err := db.GetEngine(ctx).In("lower_name", needCheckUserNames.Values()).Find(&users); err != nil {
 		return nil, err
 	}
 	for _, user := range users {
-		results[user.LowerName+"@"+setting.Service.NoReplyAddress] = user
+		results[user.GetPlaceholderEmail()] = user
 	}
 	return results, nil
 }