[proxy] make it possible to uninstall a package

This commit also brings some more refactoring under state_impl/.

1 files changed, 145 insertions, 0 deletions

diff --git a/src/hydrilla/proxy/state_impl/_operations/prune_orphans.py b/src/hydrilla/proxy/state_impl/_operations/prune_orphans.py
new file mode 100644
index 0000000..f4ebd52
--- /dev/null
+++ b/src/hydrilla/proxy/state_impl/_operations/prune_orphans.py
@@ -0,0 +1,145 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Haketilo proxy data and configuration (removal of packages that are not used).
+#
+# This file is part of Hydrilla&Haketilo.
+#
+# Copyright (C) 2022 Wojtek Kosior
+#
+# This program 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.
+#
+# This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+#
+# I, Wojtek Kosior, thereby promise not to sue for violation of this
+# file's license. Although I request that you do not make use this code
+# in a proprietary program, I am not going to enforce this in court.
+
+"""
+....
+"""
+
+# Enable using with Python 3.7.
+from __future__ import annotations
+
+import sqlite3
+
+from pathlib import Path
+
+
+_remove_item_versions_sqls = [
+    '''
+    CREATE TEMPORARY TABLE __removed_versions(
+            item_version_id INTEGER PRIMARY KEY
+    );
+    ''', '''
+    INSERT INTO
+            __removed_versions
+    SELECT
+            iv.item_version_id
+    FROM
+                 item_versions     AS iv
+            JOIN orphan_iterations AS oi USING (repo_iteration_id)
+    WHERE
+            iv.installed != 'I';
+    ''', '''
+    UPDATE
+            mapping_statuses
+    SET
+            active_version_id = NULL
+    WHERE
+            active_version_id IN __removed_versions;
+    ''', '''
+    DELETE FROM
+            item_versions
+    WHERE
+            item_version_id IN __removed_versions;
+    ''', '''
+    DROP TABLE __removed_versions;
+    '''
+]
+
+_remove_items_sql = '''
+WITH removed_items AS (
+        SELECT
+                i.item_id
+        FROM
+                          items            AS i
+                LEFT JOIN item_versions    AS iv USING (item_id)
+                LEFT JOIN mapping_statuses AS ms USING (item_id)
+        WHERE
+                 iv.item_version_id IS NULL AND
+                 (i.type = 'R' OR ms.enabled = 'N')
+)
+DELETE FROM
+        items
+WHERE
+        item_id IN removed_items;
+'''
+
+_remove_files_sql = '''
+WITH removed_files AS (
+        SELECT
+                f.file_id
+        FROM
+                          files     AS f
+                LEFT JOIN file_uses AS fu USING (file_id)
+        WHERE
+                fu.file_use_id IS NULL
+)
+DELETE FROM
+        files
+WHERE
+        file_id IN removed_files;
+'''
+
+_remove_repo_iterations_sql = '''
+WITH removed_iterations AS (
+        SELECT
+                oi.repo_iteration_id
+        FROM
+                          orphan_iterations AS oi
+                LEFT JOIN item_versions     AS iv USING (repo_iteration_id)
+        WHERE
+                iv.item_version_id IS NULL
+)
+DELETE FROM
+        repo_iterations
+WHERE
+        repo_iteration_id IN removed_iterations;
+'''
+
+_remove_repos_sql = '''
+WITH removed_repos AS (
+        SELECT
+                r.repo_id
+        FROM
+                          repos           AS r
+                LEFT JOIN repo_iterations AS ri USING (repo_id)
+        WHERE
+                r.deleted AND ri.repo_iteration_id IS NULL AND r.repo_id != 1
+)
+DELETE FROM
+        repos
+WHERE
+        repo_id IN removed_repos;
+'''
+
+def prune_orphans(cursor: sqlite3.Cursor) -> None:
+    assert cursor.connection.in_transaction
+
+    for sql in _remove_item_versions_sqls:
+        cursor.execute(sql)
+    cursor.execute(_remove_items_sql)
+    cursor.execute(_remove_files_sql)
+    cursor.execute(_remove_repo_iterations_sql)
+    cursor.execute(_remove_repos_sql)