From a99798a3123964ea97dc4462c04a82cdf2577840 Mon Sep 17 00:00:00 2001
From: lda <lda@freetards.xyz>
Date: Sun, 19 May 2024 00:30:28 +0200
Subject: [PATCH] [ADD/WIP] Start abstracting aliasing

---
 src/Room.c         | 156 ++++++++++++++++++++++++++++-----------------
 src/include/Room.h |  11 ++++
 2 files changed, 108 insertions(+), 59 deletions(-)

diff --git a/src/Room.c b/src/Room.c
index 9fc0994..5c9310e 100644
--- a/src/Room.c
+++ b/src/Room.c
@@ -181,67 +181,30 @@ RoomPopulate(Room *room, User *user, RoomCreateRequest *req, ServerPart s)
     }
 
     /* Custom alias */
-    if (req->room_alias_name)
+    if (req->room_alias_name && !RoomResolveAlias(room->db, room->id))
     {
-        DbRef *aliasesRef = DbLock(room->db, 1, "aliases");
-        HashMap *aliasesJson;
-        if (!aliasesRef)
-        {
-            aliasesRef = DbCreate(room->db, 1, "aliases");
-        }
+        CommonID full;
+        char *fullStr, *serverStr;
 
-        if (aliasesRef)
-        {
-            CommonID full;
-            char *fullStr, *serverStr;
-            HashMap *alias, *idObject;
-            Array *servers, *ids;
+        full.sigil = '#';
+        full.local = req->room_alias_name;
+        full.server = s;
+        fullStr = ParserRecomposeCommonID(full);
 
-            full.sigil = '#';
-            full.local = req->room_alias_name;
-            full.server = s;
-            
-            aliasesJson = DbJson(aliasesRef);
-            fullStr = ParserRecomposeCommonID(full);
+        serverStr = ParserRecomposeServerPart(room->creator);
+        
+        RoomAddAlias(room->db, fullStr, room->id, sender_str, serverStr);
 
-            servers = ArrayCreate();
-            serverStr = ParserRecomposeServerPart(room->creator);
-            ArrayAdd(servers, JsonValueString(serverStr));
-            Free(serverStr);
+        content = HashMapCreate();
+        JsonSet(content, JsonValueString(fullStr), 1, "alias");
+        event = RoomEventCreate(
+            sender_str, 
+            "m.room.canonical_alias", "", content);
+        JsonFree(RoomEventSend(room, event));
+        JsonFree(event);
 
-            alias = HashMapCreate();
-            HashMapSet(alias, "createdBy", JsonValueString(sender_str));
-            HashMapSet(alias, "id", JsonValueString(room->id));
-            HashMapSet(alias, "servers", JsonValueArray(servers));
-
-            JsonValueFree(JsonSet(
-                aliasesJson, JsonValueObject(alias), 2,
-                "aliases", fullStr));
-            if (!(idObject = 
-                JsonValueAsObject(JsonGet(aliasesJson, 2, "id", room->id))))
-            {
-                ids = ArrayCreate();
-                idObject = HashMapCreate();
-                HashMapSet(idObject, "aliases", JsonValueArray(ids));
-                JsonSet(
-                    aliasesJson, 
-                    JsonValueObject(idObject), 
-                    2, "id", room->id);
-            }
-            ids = JsonValueAsArray(HashMapGet(idObject, "aliases"));
-            ArrayAdd(ids, JsonValueString(fullStr));
-
-            content = HashMapCreate();
-            JsonSet(content, JsonValueString(fullStr), 1, "alias");
-            event = RoomEventCreate(
-                sender_str, 
-                "m.room.canonical_alias", "", content);
-            JsonFree(RoomEventSend(room, event));
-            JsonFree(event);
-
-            Free(fullStr);
-            DbUnlock(room->db, aliasesRef);
-        }
+        Free(fullStr);
+        Free(serverStr);
     }
     /* TODO: The rest of the events mandated by the specification on 
      * POST /createRoom, and error management. */
@@ -582,9 +545,8 @@ PopulateEventV1(Room * room, HashMap * event, PduV1 * pdu, ServerPart serv)
         JsonDuplicate(JsonValueAsObject(JsonGet(event, 1, "content")));
     pdu->room_id = StrDuplicate(room->id);
     pdu->signatures = HashMapCreate();
-    pdu->depth = RoomGetDepth(room) + 1; /* TODO: Clamp this value. */
-    pdu->depth = pdu->depth >= (int64_t) INT64_MAX ? 
-                    (int64_t) INT64_MAX : pdu->depth;
+    pdu->depth = RoomGetDepth(room) + 1;
+    pdu->depth = pdu->depth >= INT64_MAX ? INT64_MAX : pdu->depth;
 
     /* Create a random event ID for this PDU.
      * TODO: Optionally verify whenever it's already used, but that 
@@ -1804,3 +1766,79 @@ RoomGetDepth(Room *room)
 
     return max;
 }
+void
+RoomAddAlias(Db *db, char *roomAlias, char *roomId, char *sender, char *serv)
+{
+    DbRef *aliasRef;
+    HashMap *json, *alias, *idObject;
+    Array *servers, *ids;
+    if (!db || !roomAlias || !roomId || !sender || !serv)
+    {
+        return;
+    }
+
+    aliasRef = DbLock(db, 1, "aliases");
+    if (!aliasRef)
+    {
+        aliasRef = DbCreate(db, 1, "aliases");
+        if (!aliasRef)
+        {
+            return;
+        }
+    }
+
+    json = DbJson(aliasRef);
+
+    servers = ArrayCreate();
+    ArrayAdd(servers, JsonValueString(serv));
+    
+    /* alias => ID */
+    alias = HashMapCreate();
+    JsonSet(alias, JsonValueString(roomId), 1, "id");
+    JsonSet(alias, JsonValueString(sender), 1, "createdBy");
+    JsonSet(alias, JsonValueArray(servers), 1, "servers");
+
+    JsonValueFree(
+        JsonSet(json, JsonValueObject(alias), 2, "aliases", roomAlias));
+
+    /* ID => alias(es) */
+    if (!(idObject = 
+        JsonValueAsObject(JsonGet(json, 2, "id", roomId))))
+    {
+        ids = ArrayCreate();
+        idObject = HashMapCreate();
+        HashMapSet(idObject, "aliases", JsonValueArray(ids));
+        JsonSet(
+            json, 
+            JsonValueObject(idObject), 
+            2, "id", roomId);
+    }
+    ids = JsonValueAsArray(HashMapGet(idObject, "aliases"));
+    ArrayAdd(ids, JsonValueString(roomAlias));
+
+    DbUnlock(db, aliasRef);
+}
+char *
+RoomResolveAlias(Db *db, char *roomAlias)
+{
+    DbRef *aliasRef;
+    HashMap *json;
+    char *ret;
+    if (!db || !roomAlias)
+    {
+        return NULL;
+    }
+
+    aliasRef = DbLock(db, 1, "aliases");
+    if (!aliasRef)
+    {
+        return NULL;
+    }
+
+    json = DbJson(aliasRef);
+    ret = JsonValueAsString(JsonGet(json, 3, "aliases", roomAlias, "id"));
+    ret = StrDuplicate(ret);
+
+    DbUnlock(db, aliasRef);
+    return ret;
+}
diff --git a/src/include/Room.h b/src/include/Room.h
index feeec5a..67dc3ee 100644
--- a/src/include/Room.h
+++ b/src/include/Room.h
@@ -176,4 +176,15 @@ extern HashMap * RoomEventCreate(char *, char *, char *, HashMap *);
  */
 extern uint64_t RoomGetDepth(Room *);
 
+/**
+ * Tries to find an alias from room alias to an ID stored 
+ * on the heap, or NULL if it does not exist.
+ */
+extern char * RoomResolveAlias(Db *, char *);
+
+/**
+ * Adds or overwrites a room alias.
+ */
+extern void RoomAddAlias(Db *, char *, char *, char *, char *);
+
 #endif /* TELODENDRIA_ROOM_H */