add per-room mutex, possibly fixes #8

bot/mutext.go

@@ -0,0 +1,26 @@
+package bot
+
+import (
+	"sync"
+
+	"maunium.net/go/mautrix/id"
+)
+
+func (b *Bot) lock(roomID id.RoomID) {
+	_, ok := b.mu[roomID]
+	if !ok {
+		b.mu[roomID] = &sync.Mutex{}
+	}
+
+	b.mu[roomID].Lock()
+}
+
+func (b *Bot) unlock(roomID id.RoomID) {
+	_, ok := b.mu[roomID]
+	if !ok {
+		return
+	}
+
+	b.mu[roomID].Unlock()
+	delete(b.mu, roomID)
+}