From 6d4f69e3a225d8d0d68d8b77c797fc06ff63492a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?poljar=20=28Damir=20Jeli=C4=87=29?= <poljar@termina.org.uk>
Date: Thu, 22 Feb 2018 14:26:54 +0100
Subject: [PATCH] Disallow sending of multiple backlog messages in parallel.

---
 matrix/commands.py |  5 +++++
 matrix/events.py   |  1 +
 matrix/rooms.py    | 17 +++++++++--------
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/matrix/commands.py b/matrix/commands.py
index 7ae6cd7..6367420 100644
--- a/matrix/commands.py
+++ b/matrix/commands.py
@@ -108,6 +108,10 @@ def hook_commands():
 
 def matrix_fetch_old_messages(server, room_id):
     room = server.rooms[room_id]
+
+    if room.backlog_pending:
+        return
+
     prev_batch = room.prev_batch
 
     if not prev_batch:
@@ -119,6 +123,7 @@ def matrix_fetch_old_messages(server, room_id):
         token=prev_batch,
         limit=OPTIONS.backlog_limit
     )
+    room.backlog_pending = True
 
     server.send_or_queue(message)
 
diff --git a/matrix/events.py b/matrix/events.py
index 2938ba1..cb84365 100644
--- a/matrix/events.py
+++ b/matrix/events.py
@@ -343,6 +343,7 @@ class MatrixBacklogEvent(MatrixEvent):
             message.prnt(room, buf, tags)
 
         room.prev_batch = self.end_token
+        room.backlog_pending = False
 
 
 class MatrixSyncEvent(MatrixEvent):
diff --git a/matrix/rooms.py b/matrix/rooms.py
index 85c4984..8887ab5 100644
--- a/matrix/rooms.py
+++ b/matrix/rooms.py
@@ -25,14 +25,15 @@ class MatrixRoom:
     def __init__(self, room_id):
         # type: (str) -> None
         # yapf: disable
-        self.room_id = room_id  # type: str
-        self.alias = room_id    # type: str
-        self.topic = ""         # type: str
-        self.topic_author = ""  # type: str
-        self.topic_date = None  # type: datetime.datetime
-        self.prev_batch = ""    # type: str
-        self.users = dict()     # type: Dict[str, MatrixUser]
-        self.encrypted = False  # type: bool
+        self.room_id = room_id        # type: str
+        self.alias = room_id          # type: str
+        self.topic = ""               # type: str
+        self.topic_author = ""        # type: str
+        self.topic_date = None        # type: datetime.datetime
+        self.prev_batch = ""          # type: str
+        self.users = dict()           # type: Dict[str, MatrixUser]
+        self.encrypted = False        # type: bool
+        self.backlog_pending = False  # type: bool
         # yapf: enable