PYTHON-761 - Use listCollections to helper methods

pymongo/collection.py

@@ -1286,8 +1286,21 @@ class Collection(common.BaseObject):
         information on the possible options. Returns an empty
         dictionary if the collection has not been created yet.
         """
-        result = self.__database.system.namespaces.find_one(
-            {"name": self.__full_name})
+        client = self.database.connection
+        client._ensure_connected(True)
+
+        result = None
+        if client.max_wire_version > 2:
+            res = self.__database.command(
+                "listCollections",
+                filter={"name": self.__name},
+                read_preference=ReadPreference.PRIMARY)
+            for doc in res.get("collections", []):
+                result = doc
+                break
+        else:
+            result = self.__database.system.namespaces.find_one(
+                {"name": self.__full_name}, _must_use_master=True)
 
         if not result:
             return {}

pymongo/database.py

@@ -454,10 +454,19 @@ class Database(common.BaseObject):
           - `include_system_collections` (optional): if ``False`` list
             will not include system collections (e.g ``system.indexes``)
         """
-        results = self["system.namespaces"].find(_must_use_master=True)
-        names = [r["name"] for r in results]
-        names = [n[len(self.__name) + 1:] for n in names
-                 if n.startswith(self.__name + ".") and "$" not in n]
+        client = self.connection
+        client._ensure_connected(True)
+
+        if client.max_wire_version > 2:
+            results = self.command("listCollections",
+                read_preference=ReadPreference.PRIMARY).get("collections", [])
+            names = [result["name"] for result in results]
+        else:
+            names = [result["name"] for result
+                     in self["system.namespaces"].find(_must_use_master=True)]
+            names = [n[len(self.__name) + 1:] for n in names
+                     if n.startswith(self.__name + ".") and "$" not in n]
+
         if not include_system_collections:
             names = [n for n in names if not n.startswith("system.")]
         return names