refactor: Use OrderedDict for SlackChannel.messages

By using an OrderedDict, we can sort the messages when we store them, so
we don't have to sort them each time we access them with
sorted_message_keys.

If we are guaranteed that the message we store is always the newest
message, we can even drop the sorting, as OrderedDicts are sorted in
insertion order. However, I'm not sure if we might store an older
message at some point, so to be safe, we sort the messages each time we
store one.

1 files changed, 13 insertions, 15 deletions

diff --git a/wee_slack.py b/wee_slack.py
index be12cc9..38eed77 100644
--- a/wee_slack.py
+++ b/wee_slack.py
@@ -2,6 +2,7 @@
 
 from __future__ import unicode_literals
 
+from collections import OrderedDict
 from functools import wraps
 
 import time
@@ -1114,7 +1115,7 @@ class SlackChannel(object):
         self.channel_buffer = None
         self.team = kwargs.get('team', None)
         self.got_history = False
-        self.messages = {}
+        self.messages = OrderedDict()
         self.hashed_messages = {}
         self.new_messages = False
         self.typing = {}
@@ -1264,7 +1265,7 @@ class SlackChannel(object):
     def destroy_buffer(self, update_remote):
         if self.channel_buffer is not None:
             self.channel_buffer = None
-        self.messages = {}
+        self.messages = OrderedDict()
         self.hashed_messages = {}
         self.got_history = False
         # if update_remote and not eventrouter.shutting_down:
@@ -1326,14 +1327,14 @@ class SlackChannel(object):
         if from_me:
             message.message_json["user"] = team.myidentifier
         self.messages[SlackTS(message.ts)] = message
-        if len(self.messages.keys()) > SCROLLBACK_SIZE:
-            mk = self.messages.keys()
-            mk.sort()
-            for k in mk[:SCROLLBACK_SIZE]:
-                msg_to_delete = self.messages[k]
-                if msg_to_delete.hash:
-                    del self.hashed_messages[msg_to_delete.hash]
-                del self.messages[k]
+
+        sorted_messages = sorted(self.messages.items())
+        messages_to_delete = sorted_messages[:-SCROLLBACK_SIZE]
+        messages_to_keep = sorted_messages[-SCROLLBACK_SIZE:]
+        for message_hash in [m[1].hash for m in messages_to_delete]:
+            if message_hash in self.hashed_messages:
+                del self.hashed_messages[message_hash]
+        self.messages = OrderedDict(messages_to_keep)
 
     def change_message(self, ts, text=None, suffix=None):
         ts = SlackTS(ts)
@@ -1399,11 +1400,8 @@ class SlackChannel(object):
             self.eventrouter.receive(s)
 
     def sorted_message_keys(self):
-        keys = []
-        for k in self.messages:
-            if type(self.messages[k]) == SlackMessage:
-                keys.append(k)
-        return sorted(keys)
+        return [key for key, message in self.messages.items()
+                if type(message) == SlackMessage]
 
     # Typing related
     def set_typing(self, user):