start dbconn module

Signed-off-by: Mark Hymers <mhy@debian.org>

diff --git a/daklib/DBConn.py b/daklib/DBConn.py
new file mode 100644 (file)
index 0000000..05bf32d
--- /dev/null
+++ b/daklib/DBConn.py
@@ -0,0 +1,187 @@
+#!/usr/bin/env python
+
+# DB access class
+# Copyright (C) 2008  Mark Hymers <mhy@debian.org>
+
+# 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 2 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, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+################################################################################
+
+# < mhy> I need a funny comment
+# < sgran> two peanuts were walking down a dark street
+# < sgran> one was a-salted
+#  * mhy looks up the definition of "funny"
+
+################################################################################
+
+import psycopg2
+from psycopg2.extras import DictCursor
+
+from Singleton import Singleton
+from Config import Config
+
+################################################################################
+
+class Cache(object):
+    def __init__(self, hashfunc=None):
+        if hashfunc:
+            self.hashfunc = hashfunc
+        else:
+            self.hashfunc = lambda x: x['value']
+
+        self.data = {}
+
+    def SetValue(self, keys, value):
+        self.data[self.hashfunc(keys)] = value
+
+    def GetValue(self, keys):
+        return self.data.get(self.hashfunc(keys))
+
+################################################################################
+
+class DBConn(Singleton):
+    """
+    A DBConn object is a singleton containing
+    information about the connection to the SQL Database
+    """
+    def __init__(self, *args, **kwargs):
+        super(DBConn, self).__init__(*args, **kwargs)
+
+    def _startup(self, *args, **kwargs):
+        self.__createconn()
+        self.__init_caches()
+
+    ## Connection functions
+    def __createconn(self):
+        connstr = Config().GetDBConnString()
+        self.db_con = psycopg2.connect(connstr)
+
+    def reconnect(self):
+        try:
+            self.db_con.close()
+        except psycopg2.InterfaceError:
+            pass
+
+        self.db_con = None
+        self.__createconn()
+
+    ## Cache functions
+    def __init_caches(self):
+        self.caches = {'suite':         Cache(), 
+                       'section':       Cache(),
+                       'priority':      Cache(),
+                       'override_type': Cache(),
+                       'architecture':  Cache(),
+                       'archive':       Cache(),
+                       'component':     Cache(),
+                       'location':      Cache(lambda x: '%s_%s_%s' % (x['location'], x['component'], x['location'])),
+                       'maintainer':    {}, # TODO
+                       'keyring':       {}, # TODO
+                       'source':        Cache(lambda x: '%s_%s_' % (x['source'], x['version'])),
+                       'files':         {}, # TODO
+                       'maintainer':    {}, # TODO
+                       'fingerprint':   {}, # TODO
+                       'queue':         {}, # TODO
+                       'uid':           {}, # TODO
+                       'suite_version': Cache(lambda x: '%s_%s' % (x['source'], x['suite'])),
+                      }
+
+    def clear_caches(self):
+        self.__init_caches()
+
+    ## Functions to pass through to the database connector
+    def cursor(self):
+        return self.db_con.cursor()
+
+    def commit(self):
+        return self.db_con.commit()
+
+    ## Get functions
+    def __get_single_id(self, query, values, cachename=None):
+        # This is a bit of a hack but it's an internal function only
+        if cachename is not None:
+            res = self.caches[cachename].GetValue(values)
+            if res:
+                return res
+
+        c = self.db_con.cursor()
+        c.execute(query, values)
+
+        if c.rowcount != 1:
+            return None
+
+        res = c.fetchone()[0]
+
+        if cachename is not None:
+            self.caches[cachename].SetValue(values, res)
+            
+        return res
+   
+    def __get_id(self, retfield, table, qfield, value):
+        query = "SELECT %s FROM %s WHERE %s = %%(value)s" % (retfield, table, qfield)
+        return self.__get_single_id(query, {'value': value}, cachename=table)
+
+    def get_suite_id(self, suite):
+        return self.__get_id('id', 'suite', 'suite_name', suite)
+
+    def get_section_id(self, section):
+        return self.__get_id('id', 'section', 'section', section)
+
+    def get_priority_id(self, priority):
+        return self.__get_id('id', 'priority', 'priority', priority)
+
+    def get_override_type_id(self, override_type):
+        return self.__get_id('id', 'override_type', 'override_type', override_type)
+
+    def get_architecture_id(self, architecture):
+        return self.__get_id('id', 'architecture', 'arch_string', architecture)
+
+    def get_archive_id(self, archive):
+        return self.__get_id('id', 'archive', 'lower(name)', archive)
+
+    def get_component_id(self, component):
+        return self.__get_id('id', 'component', 'lower(name)', component)
+
+    def get_location_id(self, location, component, archive):
+        archive_id = self.get_archive_id(archive)
+
+        if not archive_id:
+            return None
+
+        res = None
+
+        if component:
+            component_id = self.get_component_id(component)
+            if component_id:
+                res = self.__get_single_id("SELECT id FROM location WHERE path=%(location)s AND component=%(component)d AND archive=%(archive)d",
+                        {'location': location, 'archive': archive_id, 'component': component_id}, cachename='location')
+        else:
+            res = self.__get_single_id("SELECT id FROM location WHERE path=%(location)s AND archive=%(archive)d",
+                    {'location': location, 'archive': archive_id, 'component': ''}, cachename='location')
+
+        return res
+
+    def get_source_id(self, source, version):
+        return self.__get_single_id("SELECT id FROM source s WHERE s.source=%(source)s AND s.version=%(version)s",
+                                 {'source': source, 'version': version}, cachename='source')
+
+    def get_suite_version(self, source, suite):
+        return self.__get_single_id("""
+        SELECT s.version FROM source s, suite su, src_associations sa
+        WHERE sa.source=s.id
+          AND sa.suite=su.id
+          AND su.suite_name=%(suite)s
+          AND s.source=%(source)""", {'suite': suite, 'source': source}, cachename='suite_version')
+