[V3 Config] Fix unloading and implement singleton driver (#1458)

* Add the identifier as an initialization parameter

* Remove config object singleton and opt for a shared JSON datastore

* Fix bot unloading to deal with memory leaks

* Fix tests

* Fix clear all bug

redbot/core/drivers/red_base.py

@@ -2,9 +2,9 @@ __all__ = ["BaseDriver"]
 
 
 class BaseDriver:
-    def __init__(self, cog_name):
+    def __init__(self, cog_name, identifier):
         self.cog_name = cog_name
-        self.unique_cog_identifier = None  # This is set by Config's init method
+        self.unique_cog_identifier = identifier
 
     async def get(self, *identifiers: str):
         """

redbot/core/drivers/red_json.py

@@ -1,5 +1,7 @@
 from pathlib import Path
 from typing import Tuple
+import weakref
+import logging
 
 from ..json_io import JsonIO
 
@@ -8,6 +10,28 @@ from .red_base import BaseDriver
 __all__ = ["JSON"]
 
 
+_shared_datastore = {}
+_driver_counts = {}
+_finalizers = []
+
+log = logging.getLogger("redbot.json_driver")
+
+
+def finalize_driver(cog_name):
+    if cog_name not in _driver_counts:
+        return
+
+    _driver_counts[cog_name] -= 1
+
+    if _driver_counts[cog_name] == 0:
+        if cog_name in _shared_datastore:
+            del _shared_datastore[cog_name]
+
+    for f in _finalizers:
+        if not f.alive:
+            _finalizers.remove(f)
+
+
 class JSON(BaseDriver):
     """
     Subclass of :py:class:`.red_base.BaseDriver`.
@@ -20,9 +44,9 @@ class JSON(BaseDriver):
 
         The path in which to store the file indicated by :py:attr:`file_name`.
     """
-    def __init__(self, cog_name, *, data_path_override: Path=None,
+    def __init__(self, cog_name, identifier, *, data_path_override: Path=None,
                  file_name_override: str="settings.json"):
-        super().__init__(cog_name)
+        super().__init__(cog_name, identifier)
         self.file_name = file_name_override
         if data_path_override:
             self.data_path = data_path_override
@@ -35,6 +59,26 @@ class JSON(BaseDriver):
 
         self.jsonIO = JsonIO(self.data_path)
 
+        self._load_data()
+
+    @property
+    def data(self):
+        return _shared_datastore.get(self.cog_name)
+
+    @data.setter
+    def data(self, value):
+        _shared_datastore[self.cog_name] = value
+
+    def _load_data(self):
+        if self.cog_name not in _driver_counts:
+            _driver_counts[self.cog_name] = 0
+        _driver_counts[self.cog_name] += 1
+
+        _finalizers.append(weakref.finalize(self, finalize_driver, self.cog_name))
+
+        if self.data is not None:
+            return
+
         try:
             self.data = self.jsonIO._load_json()
         except FileNotFoundError:
@@ -65,8 +109,11 @@ class JSON(BaseDriver):
         try:
             for i in full_identifiers[:-1]:
                 partial = partial[i]
-            del partial[identifiers[-1]]
+            del partial[full_identifiers[-1]]
         except KeyError:
             pass
         else:
             await self.jsonIO._threadsafe_save_json(self.data)
+
+    def get_config_details(self):
+        return

redbot/core/drivers/red_mongo.py

@@ -32,8 +32,8 @@ class Mongo(BaseDriver):
     """
     Subclass of :py:class:`.red_base.BaseDriver`.
     """
-    def __init__(self, cog_name, **kwargs):
-        super().__init__(cog_name)
+    def __init__(self, cog_name, identifier, **kwargs):
+        super().__init__(cog_name, identifier)
 
         if _conn is None:
             _initialize(**kwargs)
@@ -105,10 +105,15 @@ class Mongo(BaseDriver):
         dot_identifiers = '.'.join(identifiers)
         mongo_collection = self.get_collection()
 
-        await mongo_collection.update_one(
-            {'_id': self.unique_cog_identifier},
-            update={"$unset": {dot_identifiers: 1}}
-        )
+        if len(identifiers) > 0:
+            await mongo_collection.update_one(
+                {'_id': self.unique_cog_identifier},
+                update={"$unset": {dot_identifiers: 1}}
+            )
+        else:
+            await mongo_collection.delete_one(
+                {'_id': self.unique_cog_identifier}
+            )
 
 
 def get_config_details():