chat: added functions msg_in_cache() and msg_in_db(), also tests

chatmastermind/chat.py

@@ -6,7 +6,7 @@ from pathlib import Path
 from pprint import PrettyPrinter
 from pydoc import pager
 from dataclasses import dataclass
-from typing import TypeVar, Type, Optional, ClassVar, Any, Callable, Literal
+from typing import TypeVar, Type, Optional, ClassVar, Any, Callable, Literal, Union
 from .configuration import default_config_file
 from .message import Message, MessageFilter, MessageError, message_in
 from .tags import Tag
@@ -466,6 +466,30 @@ class ChatDB(Chat):
                 return m
         return None
 
+    def msg_in_cache(self, message: Union[Message, str]) -> bool:
+        """
+        Return true if the given Message (or filename or Message.msg_id())
+        is located in the cache directory. False otherwise.
+        """
+        if isinstance(message, Message):
+            return (message.file_path is not None
+                    and message.file_path.parent.samefile(self.cache_path)  # noqa: W503
+                    and message.file_path.exists())  # noqa: W503
+        else:
+            return len(self.msg_find([message], loc='cache')) > 0
+
+    def msg_in_db(self, message: Union[Message, str]) -> bool:
+        """
+        Return true if the given Message (or filename or Message.msg_id())
+        is located in the DB directory. False otherwise.
+        """
+        if isinstance(message, Message):
+            return (message.file_path is not None
+                    and message.file_path.parent.samefile(self.db_path)  # noqa: W503
+                    and message.file_path.exists())  # noqa: W503
+        else:
+            return len(self.msg_find([message], loc='db')) > 0
+
     def cache_read(self) -> None:
         """
         Read messages from the cache directory. New ones are added to the internal list,