git-interface: Add database abstraction layer

Add a new class that connects to the database specified in the
configuration file and provides an interface to execute SQL queries.
Prepared statements with qmark ("?") placeholders are supported.

Replace all direct database accesses with calls to the new abstraction
layer.

Signed-off-by: Lukas Fleischer <lfleischer@archlinux.org>

git-interface/db.py

@@ -0,0 +1,38 @@
+import configparser
+import mysql.connector
+import os
+
+
+class Connection:
+    _conn = None
+
+    def __init__(self):
+        config = configparser.RawConfigParser()
+        config.read(os.path.dirname(os.path.realpath(__file__)) + "/../conf/config")
+
+        aur_db_host = config.get('database', 'host')
+        aur_db_name = config.get('database', 'name')
+        aur_db_user = config.get('database', 'user')
+        aur_db_pass = config.get('database', 'password')
+        aur_db_socket = config.get('database', 'socket')
+
+        self._conn = mysql.connector.connect(host=aur_db_host,
+                                             user=aur_db_user,
+                                             passwd=aur_db_pass,
+                                             db=aur_db_name,
+                                             unix_socket=aur_db_socket,
+                                             buffered=True)
+
+    def execute(self, query, params=()):
+        query = query.replace('%', '%%').replace('?', '%s')
+
+        cur = self._conn.cursor()
+        cur.execute(query, params)
+
+        return cur
+
+    def commit(self):
+        self._conn.commit()
+
+    def close(self):
+        self._conn.close()