679 lines
24 KiB
Python
679 lines
24 KiB
Python
#-----------------------------------------------------------------------
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#
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# Copyright (C) 2000, 2001 by Autonomous Zone Industries
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# Copyright (C) 2002 Gregory P. Smith
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#
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# License: This is free software. You may use this software for any
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# purpose including modification/redistribution, so long as
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# this header remains intact and that you do not claim any
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# rights of ownership or authorship of this software. This
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# software has been tested, but no warranty is expressed or
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# implied.
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#
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# -- Gregory P. Smith <greg@electricrain.com>
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# This provides a simple database table interface built on top of
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# the Python BerkeleyDB 3 interface.
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#
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_cvsid = '$Id$'
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import string
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import sys
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try:
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import cPickle
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pickle = cPickle
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except ImportError:
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import pickle
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import whrandom
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import xdrlib
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import re
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import copy
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from bsddb.db import *
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class TableDBError(StandardError): pass
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class TableAlreadyExists(TableDBError): pass
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class Cond:
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"""This condition matches everything"""
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def __call__(self, s):
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return 1
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class ExactCond(Cond):
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"""Acts as an exact match condition function"""
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def __init__(self, strtomatch):
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self.strtomatch = strtomatch
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def __call__(self, s):
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return s == self.strtomatch
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class PrefixCond(Cond):
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"""Acts as a condition function for matching a string prefix"""
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def __init__(self, prefix):
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self.prefix = prefix
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def __call__(self, s):
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return s[:len(self.prefix)] == self.prefix
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class PostfixCond(Cond):
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"""Acts as a condition function for matching a string postfix"""
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def __init__(self, postfix):
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self.postfix = postfix
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def __call__(self, s):
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return s[-len(self.postfix):] == self.postfix
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class LikeCond(Cond):
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"""
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Acts as a function that will match using an SQL 'LIKE' style
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string. Case insensitive and % signs are wild cards.
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This isn't perfect but it should work for the simple common cases.
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"""
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def __init__(self, likestr, re_flags=re.IGNORECASE):
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# escape python re characters
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chars_to_escape = '.*+()[]?'
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for char in chars_to_escape :
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likestr = string.replace(likestr, char, '\\'+char)
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# convert %s to wildcards
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self.likestr = string.replace(likestr, '%', '.*')
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self.re = re.compile('^'+self.likestr+'$', re_flags)
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def __call__(self, s):
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return self.re.match(s)
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#
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# keys used to store database metadata
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#
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_table_names_key = '__TABLE_NAMES__' # list of the tables in this db
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_columns = '._COLUMNS__' # table_name+this key contains a list of columns
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def _columns_key(table) : return table + _columns
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#
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# these keys are found within table sub databases
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#
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_data = '._DATA_.' # this+column+this+rowid key contains table data
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_rowid = '._ROWID_.' # this+rowid+this key contains a unique entry for each
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# row in the table. (no data is stored)
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_rowid_str_len = 8 # length in bytes of the unique rowid strings
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def _data_key(table, col, rowid) : return table + _data + col + _data + rowid
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def _search_col_data_key(table, col) : return table + _data + col + _data
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def _search_all_data_key(table) : return table + _data
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def _rowid_key(table, rowid) : return table + _rowid + rowid + _rowid
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def _search_rowid_key(table) : return table + _rowid
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def contains_metastrings(s) :
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"""Verify that the given string does not contain any
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metadata strings that might interfere with dbtables database operation.
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"""
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if string.find(s, _table_names_key) >= 0 or \
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string.find(s, _columns) >= 0 or \
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string.find(s, _data) >= 0 or \
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string.find(s, _rowid) >= 0 :
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return 1
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else :
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return 0
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class bsdTableDB :
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def __init__(self, filename, dbhome, create=0, truncate=0, mode=0600,
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recover=0, dbflags=0) :
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"""bsdTableDB.open(filename, dbhome, create=0, truncate=0, mode=0600)
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Open database name in the dbhome BerkeleyDB directory.
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Use keyword arguments when calling this constructor.
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"""
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self.db = None
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myflags = DB_THREAD
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if create:
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myflags |= DB_CREATE
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flagsforenv = (DB_INIT_MPOOL | DB_INIT_LOCK | DB_INIT_LOG |
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DB_INIT_TXN | dbflags)
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# DB_AUTO_COMMIT isn't a valid flag for env.open()
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try:
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dbflags |= DB_AUTO_COMMIT
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except AttributeError:
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pass
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if recover:
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flagsforenv = flagsforenv | DB_RECOVER
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self.env = DBEnv()
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# enable auto deadlock avoidance
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self.env.set_lk_detect(DB_LOCK_DEFAULT)
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self.env.open(dbhome, myflags | flagsforenv)
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if truncate:
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myflags |= DB_TRUNCATE
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self.db = DB(self.env)
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# allow duplicate entries [warning: be careful w/ metadata]
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self.db.set_flags(DB_DUP)
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self.db.open(filename, DB_BTREE, dbflags | myflags, mode)
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self.dbfilename = filename
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# Initialize the table names list if this is a new database
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txn = self.env.txn_begin()
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try:
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if not self.db.has_key(_table_names_key, txn):
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self.db.put(_table_names_key, pickle.dumps([], 1), txn=txn)
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# Yes, bare except
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except:
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txn.abort()
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raise
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else:
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txn.commit()
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# TODO verify more of the database's metadata?
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self.__tablecolumns = {}
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def __del__(self):
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self.close()
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def close(self):
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if self.db is not None:
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self.db.close()
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self.db = None
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if self.env is not None:
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self.env.close()
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self.env = None
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def checkpoint(self, mins=0):
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try:
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self.env.txn_checkpoint(mins)
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except DBIncompleteError:
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pass
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def sync(self):
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try:
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self.db.sync()
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except DBIncompleteError:
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pass
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def _db_print(self) :
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"""Print the database to stdout for debugging"""
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print "******** Printing raw database for debugging ********"
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cur = self.db.cursor()
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try:
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key, data = cur.first()
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while 1 :
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print `{key: data}`
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next = cur.next()
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if next:
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key, data = next
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else:
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cur.close()
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return
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except DBNotFoundError:
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cur.close()
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def CreateTable(self, table, columns):
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"""CreateTable(table, columns) - Create a new table in the database
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raises TableDBError if it already exists or for other DB errors.
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"""
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assert type(columns) == type([])
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txn = None
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try:
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# checking sanity of the table and column names here on
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# table creation will prevent problems elsewhere.
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if contains_metastrings(table):
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raise ValueError(
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"bad table name: contains reserved metastrings")
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for column in columns :
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if contains_metastrings(column):
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raise ValueError(
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"bad column name: contains reserved metastrings")
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columnlist_key = _columns_key(table)
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if self.db.has_key(columnlist_key):
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raise TableAlreadyExists, "table already exists"
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txn = self.env.txn_begin()
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# store the table's column info
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self.db.put(columnlist_key, pickle.dumps(columns, 1), txn=txn)
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# add the table name to the tablelist
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tablelist = pickle.loads(self.db.get(_table_names_key, txn=txn,
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flags=DB_RMW))
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tablelist.append(table)
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# delete 1st, in case we opened with DB_DUP
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self.db.delete(_table_names_key, txn)
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self.db.put(_table_names_key, pickle.dumps(tablelist, 1), txn=txn)
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txn.commit()
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txn = None
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except DBError, dberror:
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if txn :
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txn.abort()
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raise TableDBError, dberror[1]
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def ListTableColumns(self, table):
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"""Return a list of columns in the given table.
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[] if the table doesn't exist.
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"""
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assert type(table) == type('')
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if contains_metastrings(table) :
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raise ValueError, "bad table name: contains reserved metastrings"
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columnlist_key = _columns_key(table)
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if not self.db.has_key(columnlist_key):
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return []
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pickledcolumnlist = self.db.get(columnlist_key)
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if pickledcolumnlist:
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return pickle.loads(pickledcolumnlist)
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else:
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return []
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def ListTables(self):
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"""Return a list of tables in this database."""
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pickledtablelist = self.db.get(_table_names_key)
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if pickledtablelist:
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return pickle.loads(pickledtablelist)
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else:
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return []
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def CreateOrExtendTable(self, table, columns):
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"""CreateOrExtendTable(table, columns)
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- Create a new table in the database.
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If a table of this name already exists, extend it to have any
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additional columns present in the given list as well as
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all of its current columns.
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"""
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assert type(columns) == type([])
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try:
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self.CreateTable(table, columns)
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except TableAlreadyExists:
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# the table already existed, add any new columns
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txn = None
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try:
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columnlist_key = _columns_key(table)
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txn = self.env.txn_begin()
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# load the current column list
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oldcolumnlist = pickle.loads(
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self.db.get(columnlist_key, txn=txn, flags=DB_RMW))
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# create a hash table for fast lookups of column names in the
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# loop below
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oldcolumnhash = {}
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for c in oldcolumnlist:
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oldcolumnhash[c] = c
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# create a new column list containing both the old and new
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# column names
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newcolumnlist = copy.copy(oldcolumnlist)
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for c in columns:
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if not oldcolumnhash.has_key(c):
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newcolumnlist.append(c)
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# store the table's new extended column list
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if newcolumnlist != oldcolumnlist :
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# delete the old one first since we opened with DB_DUP
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self.db.delete(columnlist_key, txn)
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self.db.put(columnlist_key,
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pickle.dumps(newcolumnlist, 1),
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txn=txn)
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txn.commit()
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txn = None
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self.__load_column_info(table)
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except DBError, dberror:
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if txn:
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txn.abort()
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raise TableDBError, dberror[1]
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def __load_column_info(self, table) :
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"""initialize the self.__tablecolumns dict"""
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# check the column names
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try:
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tcolpickles = self.db.get(_columns_key(table))
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except DBNotFoundError:
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raise TableDBError, "unknown table: " + `table`
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if not tcolpickles:
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raise TableDBError, "unknown table: " + `table`
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self.__tablecolumns[table] = pickle.loads(tcolpickles)
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def __new_rowid(self, table, txn) :
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"""Create a new unique row identifier"""
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unique = 0
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while not unique :
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# Generate a random 64-bit row ID string
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# (note: this code has <64 bits of randomness
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# but it's plenty for our database id needs!)
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p = xdrlib.Packer()
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p.pack_int(int(whrandom.random()*2147483647))
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p.pack_int(int(whrandom.random()*2147483647))
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newid = p.get_buffer()
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# Guarantee uniqueness by adding this key to the database
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try:
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self.db.put(_rowid_key(table, newid), None, txn=txn,
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flags=DB_NOOVERWRITE)
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except DBKeyExistError:
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pass
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else:
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unique = 1
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return newid
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def Insert(self, table, rowdict) :
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"""Insert(table, datadict) - Insert a new row into the table
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using the keys+values from rowdict as the column values.
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"""
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txn = None
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try:
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if not self.db.has_key(_columns_key(table)) :
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raise TableDBError, "unknown table"
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# check the validity of each column name
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if not self.__tablecolumns.has_key(table) :
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self.__load_column_info(table)
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for column in rowdict.keys() :
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if not self.__tablecolumns[table].count(column) :
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raise TableDBError, "unknown column: "+`column`
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# get a unique row identifier for this row
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txn = self.env.txn_begin()
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rowid = self.__new_rowid(table, txn=txn)
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# insert the row values into the table database
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for column, dataitem in rowdict.items() :
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# store the value
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self.db.put(_data_key(table, column, rowid), dataitem, txn=txn)
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txn.commit()
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txn = None
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except DBError, dberror:
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# WIBNI we could just abort the txn and re-raise the exception?
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# But no, because TableDBError is not related to DBError via
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# inheritance, so it would be backwards incompatible. Do the next
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# best thing.
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info = sys.exc_info()
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if txn:
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txn.abort()
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self.db.delete(_rowid_key(table, rowid))
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raise TableDBError, dberror[1], info[2]
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def Modify(self, table, conditions={}, mappings={}) :
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"""Modify(table, conditions) - Modify in rows matching 'conditions'
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using mapping functions in 'mappings'
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* conditions is a dictionary keyed on column names
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containing condition functions expecting the data string as an
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argument and returning a boolean.
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* mappings is a dictionary keyed on column names containint condition
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functions expecting the data string as an argument and returning the
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new string for that column.
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"""
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try:
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matching_rowids = self.__Select(table, [], conditions)
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# modify only requested columns
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columns = mappings.keys()
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for rowid in matching_rowids.keys() :
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txn = None
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try:
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for column in columns :
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txn = self.env.txn_begin()
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# modify the requested column
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try:
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dataitem = self.db.get(
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_data_key(table, column, rowid),
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txn)
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self.db.delete(
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_data_key(table, column, rowid),
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txn)
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except DBNotFoundError:
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# XXXXXXX row key somehow didn't exist, assume no
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# error
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dataitem = None
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dataitem = mappings[column](dataitem)
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if dataitem <> None:
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self.db.put(
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_data_key(table, column, rowid),
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dataitem, txn=txn)
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txn.commit()
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txn = None
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except DBError, dberror:
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if txn :
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txn.abort()
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raise
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except DBError, dberror:
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raise TableDBError, dberror[1]
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def Delete(self, table, conditions={}) :
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"""Delete(table, conditions) - Delete items matching the given
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conditions from the table.
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* conditions is a dictionary keyed on column names
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containing condition functions expecting the data string as an
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argument and returning a boolean.
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"""
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try:
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matching_rowids = self.__Select(table, [], conditions)
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# delete row data from all columns
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columns = self.__tablecolumns[table]
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for rowid in matching_rowids.keys() :
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txn = None
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try:
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txn = self.env.txn_begin()
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for column in columns :
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# delete the data key
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try:
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self.db.delete(_data_key(table, column, rowid),
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txn)
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except DBNotFoundError:
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# XXXXXXX column may not exist, assume no error
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pass
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try:
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self.db.delete(_rowid_key(table, rowid), txn)
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except DBNotFoundError:
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# XXXXXXX row key somehow didn't exist, assume no error
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pass
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txn.commit()
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txn = None
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except DBError, dberror:
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if txn :
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txn.abort()
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raise
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except DBError, dberror:
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raise TableDBError, dberror[1]
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def Select(self, table, columns, conditions={}) :
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"""Select(table, conditions) - retrieve specific row data
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Returns a list of row column->value mapping dictionaries.
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* columns is a list of which column data to return. If
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columns is None, all columns will be returned.
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* conditions is a dictionary keyed on column names
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containing callable conditions expecting the data string as an
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argument and returning a boolean.
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"""
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try:
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if not self.__tablecolumns.has_key(table) :
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self.__load_column_info(table)
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if columns is None :
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columns = self.__tablecolumns[table]
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matching_rowids = self.__Select(table, columns, conditions)
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except DBError, dberror:
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raise TableDBError, dberror[1]
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# return the matches as a list of dictionaries
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return matching_rowids.values()
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def __Select(self, table, columns, conditions) :
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"""__Select() - Used to implement Select and Delete (above)
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Returns a dictionary keyed on rowids containing dicts
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holding the row data for columns listed in the columns param
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that match the given conditions.
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* conditions is a dictionary keyed on column names
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containing callable conditions expecting the data string as an
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argument and returning a boolean.
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"""
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# check the validity of each column name
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if not self.__tablecolumns.has_key(table) :
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self.__load_column_info(table)
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if columns is None :
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columns = self.tablecolumns[table]
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for column in (columns + conditions.keys()) :
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if not self.__tablecolumns[table].count(column) :
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raise TableDBError, "unknown column: "+`column`
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# keyed on rows that match so far, containings dicts keyed on
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# column names containing the data for that row and column.
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matching_rowids = {}
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rejected_rowids = {} # keys are rowids that do not match
|
|
|
|
# attempt to sort the conditions in such a way as to minimize full
|
|
# column lookups
|
|
def cmp_conditions(atuple, btuple):
|
|
a = atuple[1]
|
|
b = btuple[1]
|
|
if type(a) == type(b) :
|
|
if isinstance(a, PrefixCond) and isinstance(b, PrefixCond):
|
|
# longest prefix first
|
|
return cmp(len(b.prefix), len(a.prefix))
|
|
if isinstance(a, LikeCond) and isinstance(b, LikeCond):
|
|
# longest likestr first
|
|
return cmp(len(b.likestr), len(a.likestr))
|
|
return 0
|
|
if isinstance(a, ExactCond):
|
|
return -1
|
|
if isinstance(b, ExactCond):
|
|
return 1
|
|
if isinstance(a, PrefixCond):
|
|
return -1
|
|
if isinstance(b, PrefixCond):
|
|
return 1
|
|
# leave all unknown condition callables alone as equals
|
|
return 0
|
|
|
|
conditionlist = conditions.items()
|
|
conditionlist.sort(cmp_conditions)
|
|
|
|
# Apply conditions to column data to find what we want
|
|
cur = self.db.cursor()
|
|
column_num = -1
|
|
for column, condition in conditionlist :
|
|
column_num = column_num + 1
|
|
searchkey = _search_col_data_key(table, column)
|
|
# speedup: don't linear search columns within loop
|
|
if column in columns :
|
|
savethiscolumndata = 1 # save the data for return
|
|
else :
|
|
savethiscolumndata = 0 # data only used for selection
|
|
|
|
try:
|
|
key, data = cur.set_range(searchkey)
|
|
while key[:len(searchkey)] == searchkey :
|
|
# extract the rowid from the key
|
|
rowid = key[-_rowid_str_len:]
|
|
|
|
if not rejected_rowids.has_key(rowid) :
|
|
# if no condition was specified or the condition
|
|
# succeeds, add row to our match list.
|
|
if not condition or condition(data) :
|
|
if not matching_rowids.has_key(rowid) :
|
|
matching_rowids[rowid] = {}
|
|
if savethiscolumndata :
|
|
matching_rowids[rowid][column] = data
|
|
else :
|
|
if matching_rowids.has_key(rowid) :
|
|
del matching_rowids[rowid]
|
|
rejected_rowids[rowid] = rowid
|
|
|
|
key, data = cur.next()
|
|
|
|
except DBError, dberror:
|
|
if dberror[0] != DB_NOTFOUND :
|
|
raise
|
|
continue
|
|
|
|
cur.close()
|
|
|
|
# we're done selecting rows, garbage collect the reject list
|
|
del rejected_rowids
|
|
|
|
# extract any remaining desired column data from the
|
|
# database for the matching rows.
|
|
if len(columns) > 0 :
|
|
for rowid, rowdata in matching_rowids.items() :
|
|
for column in columns :
|
|
if rowdata.has_key(column) :
|
|
continue
|
|
try:
|
|
rowdata[column] = self.db.get(
|
|
_data_key(table, column, rowid))
|
|
except DBError, dberror:
|
|
if dberror[0] != DB_NOTFOUND :
|
|
raise
|
|
rowdata[column] = None
|
|
|
|
# return the matches
|
|
return matching_rowids
|
|
|
|
|
|
def Drop(self, table) :
|
|
"""Remove an entire table from the database
|
|
"""
|
|
txn = None
|
|
try:
|
|
txn = self.env.txn_begin()
|
|
|
|
# delete the column list
|
|
self.db.delete(_columns_key(table), txn)
|
|
|
|
cur = self.db.cursor(txn)
|
|
|
|
# delete all keys containing this tables column and row info
|
|
table_key = _search_all_data_key(table)
|
|
while 1 :
|
|
try:
|
|
key, data = cur.set_range(table_key)
|
|
except DBNotFoundError:
|
|
break
|
|
# only delete items in this table
|
|
if key[:len(table_key)] != table_key :
|
|
break
|
|
cur.delete()
|
|
|
|
# delete all rowids used by this table
|
|
table_key = _search_rowid_key(table)
|
|
while 1 :
|
|
try:
|
|
key, data = cur.set_range(table_key)
|
|
except DBNotFoundError:
|
|
break
|
|
# only delete items in this table
|
|
if key[:len(table_key)] != table_key :
|
|
break
|
|
cur.delete()
|
|
|
|
cur.close()
|
|
|
|
# delete the tablename from the table name list
|
|
tablelist = pickle.loads(
|
|
self.db.get(_table_names_key, txn=txn, flags=DB_RMW))
|
|
try:
|
|
tablelist.remove(table)
|
|
except ValueError:
|
|
# hmm, it wasn't there, oh well, that's what we want.
|
|
pass
|
|
# delete 1st, incase we opened with DB_DUP
|
|
self.db.delete(_table_names_key, txn)
|
|
self.db.put(_table_names_key, pickle.dumps(tablelist, 1), txn=txn)
|
|
|
|
txn.commit()
|
|
txn = None
|
|
|
|
if self.__tablecolumns.has_key(table) :
|
|
del self.__tablecolumns[table]
|
|
|
|
except DBError, dberror:
|
|
if txn :
|
|
txn.abort()
|
|
raise TableDBError, dberror[1]
|