Restructure bot.filter_list_cache.

This is an optimization designed to eliminate all the list
comprehensions we were doing inside antimalware and filtering. The cache
is now structured so that the content is the key and the metadata is the
value.

5 files changed, 20 insertions, 21 deletions

diff --git a/bot/bot.py b/bot/bot.py
index 5deb986ec..4492feaa9 100644
--- a/bot/bot.py
+++ b/bot/bot.py
@@ -35,7 +35,7 @@ class Bot(commands.Bot):
         self.redis_ready = asyncio.Event()
         self.redis_closed = False
         self.api_client = api.APIClient(loop=self.loop)
-        self.filter_list_cache = defaultdict(list)
+        self.filter_list_cache = defaultdict(dict)
 
         self._connector = None
         self._resolver = None
@@ -169,14 +169,14 @@ class Bot(commands.Bot):
         """Add an item to the bots filter_list_cache."""
         type_ = item["type"]
         allowed = item["allowed"]
-        metadata = {
+        content = item["content"]
+
+        self.filter_list_cache[f"{type_}.{allowed}"][content] = {
             "id": item["id"],
-            "content": item["content"],
             "comment": item["comment"],
             "created_at": item["created_at"],
             "updated_at": item["updated_at"],
         }
-        self.filter_list_cache[f"{type_}.{allowed}"].append(metadata)
 
     async def login(self, *args, **kwargs) -> None:
         """Re-create the connector and set up sessions before logging into Discord."""
diff --git a/bot/cogs/antimalware.py b/bot/cogs/antimalware.py
index 9a100b3fc..c76bd2c60 100644
--- a/bot/cogs/antimalware.py
+++ b/bot/cogs/antimalware.py
@@ -40,7 +40,7 @@ class AntiMalware(Cog):
 
     def _get_whitelisted_file_formats(self) -> list:
         """Get the file formats currently on the whitelist."""
-        return [item['content'] for item in self.bot.filter_list_cache['file_format.True']]
+        return self.bot.filter_list_cache['FILE_FORMAT.True'].keys()
 
     def _get_disallowed_extensions(self, message: Message) -> t.Iterable[str]:
         """Get an iterable containing all the disallowed extensions of attachments."""
diff --git a/bot/cogs/filter_lists.py b/bot/cogs/filter_lists.py
index a93de2de9..3331be014 100644
--- a/bot/cogs/filter_lists.py
+++ b/bot/cogs/filter_lists.py
@@ -88,16 +88,16 @@ class FilterLists(Cog):
 
         # Find the content and delete it.
         log.trace(f"Trying to delete the {content} item from the {list_type} {allow_type}")
-        for allow_list in self.bot.filter_list_cache[f"{list_type}.{allowed}"]:
-            if content == allow_list.get("content"):
-                item = allow_list
+        for allow_list, metadata in self.bot.filter_list_cache[f"{list_type}.{allowed}"].items():
+            if content == allow_list:
+                item = metadata
                 break
 
         if item is not None:
             await self.bot.api_client.delete(
-                f"bot/filter-lists/{item.get('id')}"
+                f"bot/filter-lists/{item['id']}"
             )
-            self.bot.filter_list_cache[f"{list_type}.{allowed}"].remove(item)
+            del self.bot.filter_list_cache[f"{list_type}.{allowed}"][content]
             await ctx.message.add_reaction("✅")
 
     async def _list_all_data(self, ctx: Context, allowed: bool, list_type: ValidFilterListType) -> None:
@@ -107,11 +107,11 @@ class FilterLists(Cog):
 
         # Build a list of lines we want to show in the paginator
         lines = []
-        for item in result:
-            line = f"• `{item.get('content')}`"
+        for content, metadata in result.items():
+            line = f"• `{content}`"
 
-            if item.get("comment"):
-                line += f" - {item.get('comment')}"
+            if metadata.get("comment"):
+                line += f" - {metadata.get('comment')}"
 
             lines.append(line)
         lines = sorted(lines)
diff --git a/bot/cogs/filtering.py b/bot/cogs/filtering.py
index 7787d396d..0951cb740 100644
--- a/bot/cogs/filtering.py
+++ b/bot/cogs/filtering.py
@@ -101,8 +101,7 @@ class Filtering(Cog):
 
     def _get_filterlist_items(self, list_type: str, *, allowed: bool) -> list:
         """Fetch items from the filter_list_cache."""
-        items = self.bot.filter_list_cache[f"{list_type.upper()}.{allowed}"]
-        return [item["content"] for item in items]
+        return self.bot.filter_list_cache[f"{list_type.upper()}.{allowed}"].keys()
 
     @staticmethod
     def _expand_spoilers(text: str) -> str:
diff --git a/tests/bot/cogs/test_antimalware.py b/tests/bot/cogs/test_antimalware.py
index 664fa8f19..82eadf226 100644
--- a/tests/bot/cogs/test_antimalware.py
+++ b/tests/bot/cogs/test_antimalware.py
@@ -15,11 +15,11 @@ class AntiMalwareCogTests(unittest.IsolatedAsyncioTestCase):
         """Sets up fresh objects for each test."""
         self.bot = MockBot()
         self.bot.filter_list_cache = {
-            "file_format.True": [
-                {"content": ".first"},
-                {"content": ".second"},
-                {"content": ".third"}
-            ]
+            "file_format.True": {
+                ".first": {},
+                ".second": {},
+                ".third": {},
+            }
         }
         self.cog = antimalware.AntiMalware(self.bot)
         self.message = MockMessage()