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			693 lines
		
	
	
	
		
			25 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			693 lines
		
	
	
	
		
			25 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 re
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import sys
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import copy
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import xdrlib
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import whrandom
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from types import ListType, StringType
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import cPickle as pickle
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try:
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    # For Pythons w/distutils pybsddb
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    from bsddb3.db import *
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except ImportError:
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    # For Python 2.3
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    from bsddb.db import *
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class TableDBError(StandardError):
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    pass
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class TableAlreadyExists(TableDBError):
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    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 = likestr.replace(char, '\\'+char)
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        # convert %s to wildcards
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        self.likestr = likestr.replace('%', '.*')
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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):
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    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):
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    return table + _data + col + _data + rowid
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def _search_col_data_key(table, col):
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    return table + _data + col + _data
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def _search_all_data_key(table):
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    return table + _data
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def _rowid_key(table, rowid):
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    return table + _rowid + rowid + _rowid
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def _search_rowid_key(table):
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    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 (s.find(_table_names_key) >= 0 or
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        s.find(_columns) >= 0 or
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        s.find(_data) >= 0 or
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        s.find(_rowid) >= 0):
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        # Then
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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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        # this code relies on DBCursor.set* methods to raise exceptions
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        # rather than returning None
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        self.db.set_get_returns_none(1)
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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 repr({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 isinstance(columns, ListType)
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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 isinstance(table, StringType)
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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 isinstance(columns, ListType)
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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: %r" % (table,)
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        if not tcolpickles:
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            raise TableDBError, "unknown table: %r" % (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: %r" % (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
 | 
						|
                        dataitem = mappings[column](dataitem)
 | 
						|
                        if dataitem <> None:
 | 
						|
                            self.db.put(
 | 
						|
                                _data_key(table, column, rowid),
 | 
						|
                                dataitem, txn=txn)
 | 
						|
                        txn.commit()
 | 
						|
                        txn = None
 | 
						|
 | 
						|
                except DBError, dberror:
 | 
						|
                    if txn:
 | 
						|
                        txn.abort()
 | 
						|
                    raise
 | 
						|
 | 
						|
        except DBError, dberror:
 | 
						|
            raise TableDBError, dberror[1]
 | 
						|
 | 
						|
    def Delete(self, table, conditions={}):
 | 
						|
        """Delete(table, conditions) - Delete items matching the given
 | 
						|
        conditions from the table.
 | 
						|
        * conditions is a dictionary keyed on column names
 | 
						|
        containing condition functions expecting the data string as an
 | 
						|
        argument and returning a boolean.
 | 
						|
        """
 | 
						|
        try:
 | 
						|
            matching_rowids = self.__Select(table, [], conditions)
 | 
						|
 | 
						|
            # delete row data from all columns
 | 
						|
            columns = self.__tablecolumns[table]
 | 
						|
            for rowid in matching_rowids.keys():
 | 
						|
                txn = None
 | 
						|
                try:
 | 
						|
                    txn = self.env.txn_begin()
 | 
						|
                    for column in columns:
 | 
						|
                        # delete the data key
 | 
						|
                        try:
 | 
						|
                            self.db.delete(_data_key(table, column, rowid),
 | 
						|
                                           txn)
 | 
						|
                        except DBNotFoundError:
 | 
						|
                            # XXXXXXX column may not exist, assume no error
 | 
						|
                            pass
 | 
						|
 | 
						|
                    try:
 | 
						|
                        self.db.delete(_rowid_key(table, rowid), txn)
 | 
						|
                    except DBNotFoundError:
 | 
						|
                        # XXXXXXX row key somehow didn't exist, assume no error
 | 
						|
                        pass
 | 
						|
                    txn.commit()
 | 
						|
                    txn = None
 | 
						|
                except DBError, dberror:
 | 
						|
                    if txn:
 | 
						|
                        txn.abort()
 | 
						|
                    raise
 | 
						|
        except DBError, dberror:
 | 
						|
            raise TableDBError, dberror[1]
 | 
						|
 | 
						|
 | 
						|
    def Select(self, table, columns, conditions={}):
 | 
						|
        """Select(table, conditions) - retrieve specific row data
 | 
						|
        Returns a list of row column->value mapping dictionaries.
 | 
						|
        * columns is a list of which column data to return.  If
 | 
						|
          columns is None, all columns will be returned.
 | 
						|
        * conditions is a dictionary keyed on column names
 | 
						|
          containing callable conditions expecting the data string as an
 | 
						|
          argument and returning a boolean.
 | 
						|
        """
 | 
						|
        try:
 | 
						|
            if not self.__tablecolumns.has_key(table):
 | 
						|
                self.__load_column_info(table)
 | 
						|
            if columns is None:
 | 
						|
                columns = self.__tablecolumns[table]
 | 
						|
            matching_rowids = self.__Select(table, columns, conditions)
 | 
						|
        except DBError, dberror:
 | 
						|
            raise TableDBError, dberror[1]
 | 
						|
        # return the matches as a list of dictionaries
 | 
						|
        return matching_rowids.values()
 | 
						|
 | 
						|
 | 
						|
    def __Select(self, table, columns, conditions):
 | 
						|
        """__Select() - Used to implement Select and Delete (above)
 | 
						|
        Returns a dictionary keyed on rowids containing dicts
 | 
						|
        holding the row data for columns listed in the columns param
 | 
						|
        that match the given conditions.
 | 
						|
        * conditions is a dictionary keyed on column names
 | 
						|
        containing callable conditions expecting the data string as an
 | 
						|
        argument and returning a boolean.
 | 
						|
        """
 | 
						|
        # check the validity of each column name
 | 
						|
        if not self.__tablecolumns.has_key(table):
 | 
						|
            self.__load_column_info(table)
 | 
						|
        if columns is None:
 | 
						|
            columns = self.tablecolumns[table]
 | 
						|
        for column in (columns + conditions.keys()):
 | 
						|
            if not self.__tablecolumns[table].count(column):
 | 
						|
                raise TableDBError, "unknown column: %r" % (column,)
 | 
						|
 | 
						|
        # keyed on rows that match so far, containings dicts keyed on
 | 
						|
        # column names containing the data for that row and column.
 | 
						|
        matching_rowids = {}
 | 
						|
        # keys are rowids that do not match
 | 
						|
        rejected_rowids = {}
 | 
						|
 | 
						|
        # 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) is 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]
 |