[pylint.message] Create a MessageIdStore class

1 files changed, 123 insertions, 0 deletions

diff --git a/pylint/message/message_id_store.py b/pylint/message/message_id_store.py
new file mode 100644
index 000000000..b8f0206c9
--- /dev/null
+++ b/pylint/message/message_id_store.py
@@ -0,0 +1,123 @@
+# -*- coding: utf-8 -*-
+
+# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+# For details: https://github.com/PyCQA/pylint/blob/master/COPYING
+
+from typing import List
+
+from pylint.exceptions import InvalidMessageError, UnknownMessageError
+
+
+class MessageIdStore:
+
+    """The MessageIdStore store MessageId and make sure that there is a 1-1 relation between msgid and symbol."""
+
+    def __init__(self):
+        self.__msgid_to_symbol = {}
+        self.__symbol_to_msgid = {}
+        self.__old_names = {}
+
+    def __len__(self):
+        return len(self.__msgid_to_symbol)
+
+    def __repr__(self):
+        result = "MessageIdStore: [\n"
+        for msgid, symbol in self.__msgid_to_symbol.items():
+            result += "  - {msgid} ({symbol})\n".format(msgid=msgid, symbol=symbol)
+        result += "]"
+        return result
+
+    def get_symbol(self, msgid: str) -> str:
+        return self.__msgid_to_symbol[msgid]
+
+    def get_msgid(self, symbol: str) -> str:
+        return self.__symbol_to_msgid[symbol]
+
+    def register_message_definition(self, message_definition):
+        self.check_msgid_and_symbol(message_definition.msgid, message_definition.symbol)
+        self.add_msgid_and_symbol(message_definition.msgid, message_definition.symbol)
+        for old_msgid, old_symbol in message_definition.old_names:
+            self.check_msgid_and_symbol(old_msgid, old_symbol)
+            self.add_legacy_msgid_and_symbol(
+                old_msgid, old_symbol, message_definition.msgid
+            )
+
+    def add_msgid_and_symbol(self, msgid: str, symbol: str) -> None:
+        """Add valid message id.
+
+        There is a little duplication with add_legacy_msgid_and_symbol to avoid a function call,
+        this is called a lot at initialization."""
+        self.__msgid_to_symbol[msgid] = symbol
+        self.__symbol_to_msgid[symbol] = msgid
+
+    def add_legacy_msgid_and_symbol(self, msgid: str, symbol: str, new_msgid: str):
+        """Add valid legacy message id.
+
+        There is a little duplication with add_msgid_and_symbol to avoid a function call,
+        this is called a lot at initialization."""
+        self.__msgid_to_symbol[msgid] = symbol
+        self.__symbol_to_msgid[symbol] = msgid
+        existing_old_names = self.__old_names.get(msgid, [])
+        existing_old_names.append(new_msgid)
+        self.__old_names[msgid] = existing_old_names
+
+    def check_msgid_and_symbol(self, msgid: str, symbol: str) -> None:
+        existing_msgid = self.__symbol_to_msgid.get(symbol)
+        existing_symbol = self.__msgid_to_symbol.get(msgid)
+        if existing_symbol is None and existing_msgid is None:
+            return
+        if existing_msgid is not None:
+            if existing_msgid != msgid:
+                self._raise_duplicate_msgid(symbol, msgid, existing_msgid)
+        if existing_symbol != symbol:
+            self._raise_duplicate_symbol(msgid, symbol, existing_symbol)
+
+    @staticmethod
+    def _raise_duplicate_symbol(msgid, symbol, other_symbol):
+        """Raise an error when a symbol is duplicated.
+
+        :param str msgid: The msgid corresponding to the symbols
+        :param str symbol: Offending symbol
+        :param str other_symbol: Other offending symbol
+        :raises InvalidMessageError:"""
+        symbols = [symbol, other_symbol]
+        symbols.sort()
+        error_message = "Message id '{msgid}' cannot have both ".format(msgid=msgid)
+        error_message += "'{other_symbol}' and '{symbol}' as symbolic name.".format(
+            other_symbol=symbols[0], symbol=symbols[1]
+        )
+        raise InvalidMessageError(error_message)
+
+    @staticmethod
+    def _raise_duplicate_msgid(symbol, msgid, other_msgid):
+        """Raise an error when a msgid is duplicated.
+
+        :param str symbol: The symbol corresponding to the msgids
+        :param str msgid: Offending msgid
+        :param str other_msgid: Other offending msgid
+        :raises InvalidMessageError:"""
+        msgids = [msgid, other_msgid]
+        msgids.sort()
+        error_message = (
+            "Message symbol '{symbol}' cannot be used for "
+            "'{other_msgid}' and '{msgid}' at the same time."
+            " If you're creating an 'old_names' use 'old-{symbol}' as the old symbol."
+        ).format(symbol=symbol, other_msgid=msgids[0], msgid=msgids[1])
+        raise InvalidMessageError(error_message)
+
+    def get_active_msgids(self, msgid_or_symbol: str) -> List[str]:
+        """Return msgids but the input can be a symbol."""
+        # Only msgid can have a digit as second letter
+        is_msgid = msgid_or_symbol[1:].isdigit()
+        if is_msgid:
+            msgid = msgid_or_symbol.upper()
+            symbol = self.__msgid_to_symbol.get(msgid)
+        else:
+            msgid = self.__symbol_to_msgid.get(msgid_or_symbol)
+            symbol = msgid_or_symbol
+        if not msgid or not symbol:
+            error_msg = "No such message id or symbol '{msgid_or_symbol}'.".format(
+                msgid_or_symbol=msgid_or_symbol
+            )
+            raise UnknownMessageError(error_msg)
+        return [msgid]