From 8503564a77152e407af8d2d74f588c03a5c63120 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Wed, 1 Apr 2020 17:15:03 +0100
Subject: [PATCH] Fixup protocol.py

---
 synapse/replication/tcp/protocol.py | 89 ++---------------------------
 1 file changed, 6 insertions(+), 83 deletions(-)

diff --git a/synapse/replication/tcp/protocol.py b/synapse/replication/tcp/protocol.py
index 7dc2828ad1..f2a37f568e 100644
--- a/synapse/replication/tcp/protocol.py
+++ b/synapse/replication/tcp/protocol.py
@@ -46,12 +46,11 @@ indicate which side is sending, these are *not* included on the wire::
     > ERROR server stopping
     * connection closed by server *
 """
-import abc
 import fcntl
 import logging
 import struct
 from collections import defaultdict
-from typing import Any, DefaultDict, Dict, List, Set
+from typing import TYPE_CHECKING, DefaultDict, List
 
 from six import iteritems
 
@@ -78,13 +77,12 @@ from synapse.replication.tcp.commands import (
     SyncCommand,
     UserSyncCommand,
 )
-from synapse.replication.tcp.streams import STREAMS_MAP, Stream
 from synapse.types import Collection
 from synapse.util import Clock
 from synapse.util.stringutils import random_string
 
-MYPY = False
-if MYPY:
+if TYPE_CHECKING:
+    from synapse.replication.tcp.handler import ReplicationCommandHandler
     from synapse.server import HomeServer
 
 
@@ -475,71 +473,6 @@ class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol):
         self.streamer.lost_connection(self)
 
 
-class AbstractReplicationClientHandler(metaclass=abc.ABCMeta):
-    """
-    The interface for the handler that should be passed to
-    ClientReplicationStreamProtocol
-    """
-
-    @abc.abstractmethod
-    async def on_rdata(self, stream_name, token, rows):
-        """Called to handle a batch of replication data with a given stream token.
-
-        Args:
-            stream_name (str): name of the replication stream for this batch of rows
-            token (int): stream token for this batch of rows
-            rows (list): a list of Stream.ROW_TYPE objects as returned by
-                Stream.parse_row.
-        """
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    async def on_position(self, stream_name, token):
-        """Called when we get new position data."""
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def on_sync(self, data):
-        """Called when get a new SYNC command."""
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    async def on_remote_server_up(self, server: str):
-        """Called when get a new REMOTE_SERVER_UP command."""
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def get_streams_to_replicate(self):
-        """Called when a new connection has been established and we need to
-        subscribe to streams.
-
-        Returns:
-            map from stream name to the most recent update we have for
-            that stream (ie, the point we want to start replicating from)
-        """
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def get_currently_syncing_users(self):
-        """Get the list of currently syncing users (if any). This is called
-        when a connection has been established and we need to send the
-        currently syncing users."""
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def update_connection(self, connection):
-        """Called when a connection has been established (or lost with None).
-        """
-        raise NotImplementedError()
-
-    @abc.abstractmethod
-    def finished_connecting(self):
-        """Called when we have successfully subscribed and caught up to all
-        streams we're interested in.
-        """
-        raise NotImplementedError()
-
-
 class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
     VALID_INBOUND_COMMANDS = VALID_SERVER_COMMANDS
     VALID_OUTBOUND_COMMANDS = VALID_CLIENT_COMMANDS
@@ -550,7 +483,7 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
         client_name: str,
         server_name: str,
         clock: Clock,
-        command_handler,
+        command_handler: "ReplicationCommandHandler",
     ):
         BaseReplicationStreamProtocol.__init__(self, clock)
 
@@ -560,17 +493,6 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
         self.server_name = server_name
         self.handler = command_handler
 
-        self.streams = {
-            stream.NAME: stream(hs) for stream in STREAMS_MAP.values()
-        }  # type: Dict[str, Stream]
-
-        # Set of streams that we're currently catching up with.
-        self.streams_connecting = set()  # type: Set[str]
-
-        # Map of stream to batched updates. See RdataCommand for info on how
-        # batching works.
-        self.pending_batches = {}  # type: Dict[str, List[Any]]
-
     def connectionMade(self):
         self.send_command(NameCommand(self.client_name))
         BaseReplicationStreamProtocol.connectionMade(self)
@@ -592,7 +514,8 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
     async def handle_command(self, cmd: Command):
         """Handle a command we have received over the replication stream.
 
-        By default delegates to on_<COMMAND>, which should return an awaitable.
+        Delegates to `command_handler.on_<COMMAND>`, which must return an
+        awaitable.
 
         Args:
             cmd: received command