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import logging
import os.path
import errno
import sys
import warnings
import sqlite3
try:
import sqlite3
except ImportError:
from pysqlite2 import dbapi2 as sqlite3
sqlversion = sqlite3.sqlite_version_info
if sqlversion[0] < 3 or (sqlversion[0] == 3 and sqlversion[1] < 3):
raise Exception("sqlite3 version 3.3.0 or later is required.")
class NotFoundError(StandardError):
pass
class PRTable():
def __init__(self,cursor,table):
self.cursor = cursor
self.table = table
#create the table
self._execute("CREATE TABLE IF NOT EXISTS %s \
(version TEXT NOT NULL, \
checksum TEXT NOT NULL, \
value INTEGER, \
PRIMARY KEY (version,checksum));"
% table)
def _execute(self, *query):
"""Execute a query, waiting to acquire a lock if necessary"""
count = 0
while True:
try:
return self.cursor.execute(*query)
except sqlite3.OperationalError as exc:
if 'database is locked' in str(exc) and count < 500:
count = count + 1
continue
raise
except sqlite3.IntegrityError as exc:
print "Integrity error %s" % str(exc)
break
def getValue(self, version, checksum):
data=self._execute("SELECT value FROM %s WHERE version=? AND checksum=?;" % self.table,
(version,checksum))
row=data.fetchone()
if row != None:
return row[0]
else:
#no value found, try to insert
self._execute("INSERT INTO %s VALUES (?, ?, (select ifnull(max(value)+1,0) from %s where version=?));"
% (self.table,self.table),
(version,checksum,version))
data=self._execute("SELECT value FROM %s WHERE version=? AND checksum=?;" % self.table,
(version,checksum))
row=data.fetchone()
if row != None:
return row[0]
else:
raise NotFoundError
class PRData(object):
"""Object representing the PR database"""
def __init__(self, filename):
self.filename=os.path.abspath(filename)
#build directory hierarchy
try:
os.makedirs(os.path.dirname(self.filename))
except OSError as e:
if e.errno != errno.EEXIST:
raise e
self.connection=sqlite3.connect(self.filename, timeout=5,
isolation_level=None)
self.cursor=self.connection.cursor()
self._tables={}
def __del__(self):
print "PRData: closing DB %s" % self.filename
self.connection.close()
def __getitem__(self,tblname):
if not isinstance(tblname, basestring):
raise TypeError("tblname argument must be a string, not '%s'" %
type(tblname))
if tblname in self._tables:
return self._tables[tblname]
else:
tableobj = self._tables[tblname] = PRTable(self.cursor, tblname)
return tableobj
def __delitem__(self, tblname):
if tblname in self._tables:
del self._tables[tblname]
logging.info("drop table %s" % (tblname))
self.cursor.execute("DROP TABLE IF EXISTS %s;" % tblname)
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