1 files changed, 42 insertions, 0 deletions
diff --git a/src/mailman/utilities/queries.py b/src/mailman/utilities/queries.py
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index 000000000..6f4bc6b4d
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+++ b/src/mailman/utilities/queries.py
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+# Copyright (C) 2016 by the Free Software Foundation, Inc.
+#
+# This file is part of GNU Mailman.
+#
+# GNU Mailman is free software: you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option)
+# any later version.
+#
+# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Some helpers for queries."""
+
+__all__ = [
+    'QuerySequence',
+    ]
+
+
+from collections.abc import Sequence
+
+
+class QuerySequence(Sequence):
+    def __init__(self, query=None):
+        super().__init__()
+        self._query = query
+        self._cached_results = None
+
+    def __len__(self):
+        return (0 if self._query is None else self._query.count())
+
+    def __getitem__(self, index):
+        if self._query is None:
+            raise IndexError('index out of range')
+        if self._cached_results is None:
+            self._cached_results = list(self._query)
+        return self._cached_results[index]