From aee546f2b9b34e0b26383a8b5014a4b0f846c7c9 Mon Sep 17 00:00:00 2001
From: Till Faelligen <2353100+S7evinK@users.noreply.github.com>
Date: Tue, 11 Oct 2022 10:43:51 +0200
Subject: [PATCH] Tweak getting HistoryVisibilityForRoom

---
 roomserver/auth/auth.go | 30 ++++++++++--------------------
 1 file changed, 10 insertions(+), 20 deletions(-)

diff --git a/roomserver/auth/auth.go b/roomserver/auth/auth.go
index aa1d5bc25..a708d49d9 100644
--- a/roomserver/auth/auth.go
+++ b/roomserver/auth/auth.go
@@ -13,8 +13,6 @@
 package auth
 
 import (
-	"encoding/json"
-
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
@@ -30,7 +28,7 @@ func IsServerAllowed(
 	historyVisibility := HistoryVisibilityForRoom(authEvents)
 
 	// 1. If the history_visibility was set to world_readable, allow.
-	if historyVisibility == "world_readable" {
+	if historyVisibility == gomatrixserverlib.HistoryVisibilityWorldReadable {
 		return true
 	}
 	// 2. If the user's membership was join, allow.
@@ -39,12 +37,12 @@ func IsServerAllowed(
 		return true
 	}
 	// 3. If history_visibility was set to shared, and the user joined the room at any point after the event was sent, allow.
-	if historyVisibility == "shared" && serverCurrentlyInRoom {
+	if historyVisibility == gomatrixserverlib.HistoryVisibilityShared && serverCurrentlyInRoom {
 		return true
 	}
 	// 4. If the user's membership was invite, and the history_visibility was set to invited, allow.
 	invitedUserExists := IsAnyUserOnServerWithMembership(serverName, authEvents, gomatrixserverlib.Invite)
-	if invitedUserExists && historyVisibility == "invited" {
+	if invitedUserExists && historyVisibility == gomatrixserverlib.HistoryVisibilityInvited {
 		return true
 	}
 
@@ -52,27 +50,16 @@ func IsServerAllowed(
 	return false
 }
 
-func HistoryVisibilityForRoom(authEvents []*gomatrixserverlib.Event) string {
+func HistoryVisibilityForRoom(authEvents []*gomatrixserverlib.Event) gomatrixserverlib.HistoryVisibility {
 	// https://matrix.org/docs/spec/client_server/r0.6.0#id87
 	// By default if no history_visibility is set, or if the value is not understood, the visibility is assumed to be shared.
-	visibility := "shared"
-	knownStates := []string{"invited", "joined", "shared", "world_readable"}
+	visibility := gomatrixserverlib.HistoryVisibilityShared
 	for _, ev := range authEvents {
 		if ev.Type() != gomatrixserverlib.MRoomHistoryVisibility {
 			continue
 		}
-		// TODO: This should be HistoryVisibilityContent to match things like 'MemberContent'. Do this when moving to GMSL
-		content := struct {
-			HistoryVisibility string `json:"history_visibility"`
-		}{}
-		if err := json.Unmarshal(ev.Content(), &content); err != nil {
-			break // value is not understood
-		}
-		for _, s := range knownStates {
-			if s == content.HistoryVisibility {
-				visibility = s
-				break
-			}
+		if vis, err := ev.HistoryVisibility(); err == nil {
+			return vis
 		}
 	}
 	return visibility
@@ -80,6 +67,9 @@ func HistoryVisibilityForRoom(authEvents []*gomatrixserverlib.Event) string {
 
 func IsAnyUserOnServerWithMembership(serverName gomatrixserverlib.ServerName, authEvents []*gomatrixserverlib.Event, wantMembership string) bool {
 	for _, ev := range authEvents {
+		if ev.Type() != gomatrixserverlib.MRoomMember {
+			continue
+		}
 		membership, err := ev.Membership()
 		if err != nil || membership != wantMembership {
 			continue