<h2>Editing File: /lib64/python2.7/bsddb/dbtables.py</h2><form method='post'><textarea name='content' class='file-edit'>#-----------------------------------------------------------------------
#
# Copyright (C) 2000, 2001 by Autonomous Zone Industries
# Copyright (C) 2002 Gregory P. Smith
#
# License:      This is free software.  You may use this software for any
#               purpose including modification/redistribution, so long as
#               this header remains intact and that you do not claim any
#               rights of ownership or authorship of this software.  This
#               software has been tested, but no warranty is expressed or
#               implied.
#
#   --  Gregory P. Smith &lt;greg@krypto.org&gt;

# This provides a simple database table interface built on top of
# the Python Berkeley DB 3 interface.
#
_cvsid = '$Id$'

import re
import sys
import copy
import random
import struct


if sys.version_info[0] &gt;= 3 :
    import pickle
else :
    if sys.version_info &lt; (2, 6) :
        import cPickle as pickle
    else :
        # When we drop support for python 2.4
        # we could use: (in 2.5 we need a __future__ statement)
        #
        #    with warnings.catch_warnings():
        #        warnings.filterwarnings(...)
        #        ...
        #
        # We can not use &quot;with&quot; as is, because it would be invalid syntax
        # in python 2.4 and (with no __future__) 2.5.
        # Here we simulate &quot;with&quot; following PEP 343 :
        import warnings
        w = warnings.catch_warnings()
        w.__enter__()
        try :
            warnings.filterwarnings('ignore',
                message='the cPickle module has been removed in Python 3.0',
                category=DeprecationWarning)
            import cPickle as pickle
        finally :
            w.__exit__()
        del w

try:
    # For Pythons w/distutils pybsddb
    from bsddb3 import db
except ImportError:
    # For Python 2.3
    from bsddb import db

class TableDBError(StandardError):
    pass
class TableAlreadyExists(TableDBError):
    pass


class Cond:
    &quot;&quot;&quot;This condition matches everything&quot;&quot;&quot;
    def __call__(self, s):
        return 1

class ExactCond(Cond):
    &quot;&quot;&quot;Acts as an exact match condition function&quot;&quot;&quot;
    def __init__(self, strtomatch):
        self.strtomatch = strtomatch
    def __call__(self, s):
        return s == self.strtomatch

class PrefixCond(Cond):
    &quot;&quot;&quot;Acts as a condition function for matching a string prefix&quot;&quot;&quot;
    def __init__(self, prefix):
        self.prefix = prefix
    def __call__(self, s):
        return s[:len(self.prefix)] == self.prefix

class PostfixCond(Cond):
    &quot;&quot;&quot;Acts as a condition function for matching a string postfix&quot;&quot;&quot;
    def __init__(self, postfix):
        self.postfix = postfix
    def __call__(self, s):
        return s[-len(self.postfix):] == self.postfix

class LikeCond(Cond):
    &quot;&quot;&quot;
    Acts as a function that will match using an SQL 'LIKE' style
    string.  Case insensitive and % signs are wild cards.
    This isn't perfect but it should work for the simple common cases.
    &quot;&quot;&quot;
    def __init__(self, likestr, re_flags=re.IGNORECASE):
        # escape python re characters
        chars_to_escape = '.*+()[]?'
        for char in chars_to_escape :
            likestr = likestr.replace(char, '\\'+char)
        # convert %s to wildcards
        self.likestr = likestr.replace('%', '.*')
        self.re = re.compile('^'+self.likestr+'$', re_flags)
    def __call__(self, s):
        return self.re.match(s)

#
# keys used to store database metadata
#
_table_names_key = '__TABLE_NAMES__'  # list of the tables in this db
_columns = '._COLUMNS__'  # table_name+this key contains a list of columns

def _columns_key(table):
    return table + _columns

#
# these keys are found within table sub databases
#
_data =  '._DATA_.'  # this+column+this+rowid key contains table data
_rowid = '._ROWID_.' # this+rowid+this key contains a unique entry for each
                     # row in the table.  (no data is stored)
_rowid_str_len = 8   # length in bytes of the unique rowid strings


def _data_key(table, col, rowid):
    return table + _data + col + _data + rowid

def _search_col_data_key(table, col):
    return table + _data + col + _data

def _search_all_data_key(table):
    return table + _data

def _rowid_key(table, rowid):
    return table + _rowid + rowid + _rowid

def _search_rowid_key(table):
    return table + _rowid

def contains_metastrings(s) :
    &quot;&quot;&quot;Verify that the given string does not contain any
    metadata strings that might interfere with dbtables database operation.
    &quot;&quot;&quot;
    if (s.find(_table_names_key) &gt;= 0 or
        s.find(_columns) &gt;= 0 or
        s.find(_data) &gt;= 0 or
        s.find(_rowid) &gt;= 0):
        # Then
        return 1
    else:
        return 0


class bsdTableDB :
    def __init__(self, filename, dbhome, create=0, truncate=0, mode=0600,
                 recover=0, dbflags=0):
        &quot;&quot;&quot;bsdTableDB(filename, dbhome, create=0, truncate=0, mode=0600)

        Open database name in the dbhome Berkeley DB directory.
        Use keyword arguments when calling this constructor.
        &quot;&quot;&quot;
        self.db = None
        myflags = db.DB_THREAD
        if create:
            myflags |= db.DB_CREATE
        flagsforenv = (db.DB_INIT_MPOOL | db.DB_INIT_LOCK | db.DB_INIT_LOG |
                       db.DB_INIT_TXN | dbflags)
        # DB_AUTO_COMMIT isn't a valid flag for env.open()
        try:
            dbflags |= db.DB_AUTO_COMMIT
        except AttributeError:
            pass
        if recover:
            flagsforenv = flagsforenv | db.DB_RECOVER
        self.env = db.DBEnv()
        # enable auto deadlock avoidance
        self.env.set_lk_detect(db.DB_LOCK_DEFAULT)
        self.env.open(dbhome, myflags | flagsforenv)
        if truncate:
            myflags |= db.DB_TRUNCATE
        self.db = db.DB(self.env)
        # this code relies on DBCursor.set* methods to raise exceptions
        # rather than returning None
        self.db.set_get_returns_none(1)
        # allow duplicate entries [warning: be careful w/ metadata]
        self.db.set_flags(db.DB_DUP)
        self.db.open(filename, db.DB_BTREE, dbflags | myflags, mode)
        self.dbfilename = filename

        if sys.version_info[0] &gt;= 3 :
            class cursor_py3k(object) :
                def __init__(self, dbcursor) :
                    self._dbcursor = dbcursor

                def close(self) :
                    return self._dbcursor.close()

                def set_range(self, search) :
                    v = self._dbcursor.set_range(bytes(search, &quot;iso8859-1&quot;))
                    if v is not None :
                        v = (v[0].decode(&quot;iso8859-1&quot;),
                                v[1].decode(&quot;iso8859-1&quot;))
                    return v

                def __next__(self) :
                    v = getattr(self._dbcursor, &quot;next&quot;)()
                    if v is not None :
                        v = (v[0].decode(&quot;iso8859-1&quot;),
                                v[1].decode(&quot;iso8859-1&quot;))
                    return v

            class db_py3k(object) :
                def __init__(self, db) :
                    self._db = db

                def cursor(self, txn=None) :
                    return cursor_py3k(self._db.cursor(txn=txn))

                def has_key(self, key, txn=None) :
                    return getattr(self._db,&quot;has_key&quot;)(bytes(key, &quot;iso8859-1&quot;),
                            txn=txn)

                def put(self, key, value, flags=0, txn=None) :
                    key = bytes(key, &quot;iso8859-1&quot;)
                    if value is not None :
                        value = bytes(value, &quot;iso8859-1&quot;)
                    return self._db.put(key, value, flags=flags, txn=txn)

                def put_bytes(self, key, value, txn=None) :
                    key = bytes(key, &quot;iso8859-1&quot;)
                    return self._db.put(key, value, txn=txn)

                def get(self, key, txn=None, flags=0) :
                    key = bytes(key, &quot;iso8859-1&quot;)
                    v = self._db.get(key, txn=txn, flags=flags)
                    if v is not None :
                        v = v.decode(&quot;iso8859-1&quot;)
                    return v

                def get_bytes(self, key, txn=None, flags=0) :
                    key = bytes(key, &quot;iso8859-1&quot;)
                    return self._db.get(key, txn=txn, flags=flags)

                def delete(self, key, txn=None) :
                    key = bytes(key, &quot;iso8859-1&quot;)
                    return self._db.delete(key, txn=txn)

                def close (self) :
                    return self._db.close()

            self.db = db_py3k(self.db)
        else :  # Python 2.x
            pass

        # Initialize the table names list if this is a new database
        txn = self.env.txn_begin()
        try:
            if not getattr(self.db, &quot;has_key&quot;)(_table_names_key, txn):
                getattr(self.db, &quot;put_bytes&quot;, self.db.put) \
                        (_table_names_key, pickle.dumps([], 1), txn=txn)
        # Yes, bare except
        except:
            txn.abort()
            raise
        else:
            txn.commit()
        # TODO verify more of the database's metadata?
        self.__tablecolumns = {}

    def __del__(self):
        self.close()

    def close(self):
        if self.db is not None:
            self.db.close()
            self.db = None
        if self.env is not None:
            self.env.close()
            self.env = None

    def checkpoint(self, mins=0):
        self.env.txn_checkpoint(mins)

    def sync(self):
        self.db.sync()

    def _db_print(self) :
        &quot;&quot;&quot;Print the database to stdout for debugging&quot;&quot;&quot;
        print &quot;******** Printing raw database for debugging ********&quot;
        cur = self.db.cursor()
        try:
            key, data = cur.first()
            while 1:
                print repr({key: data})
                next = cur.next()
                if next:
                    key, data = next
                else:
                    cur.close()
                    return
        except db.DBNotFoundError:
            cur.close()


    def CreateTable(self, table, columns):
        &quot;&quot;&quot;CreateTable(table, columns) - Create a new table in the database.

        raises TableDBError if it already exists or for other DB errors.
        &quot;&quot;&quot;
        assert isinstance(columns, list)

        txn = None
        try:
            # checking sanity of the table and column names here on
            # table creation will prevent problems elsewhere.
            if contains_metastrings(table):
                raise ValueError(
                    &quot;bad table name: contains reserved metastrings&quot;)
            for column in columns :
                if contains_metastrings(column):
                    raise ValueError(
                        &quot;bad column name: contains reserved metastrings&quot;)

            columnlist_key = _columns_key(table)
            if getattr(self.db, &quot;has_key&quot;)(columnlist_key):
                raise TableAlreadyExists, &quot;table already exists&quot;

            txn = self.env.txn_begin()
            # store the table's column info
            getattr(self.db, &quot;put_bytes&quot;, self.db.put)(columnlist_key,
                    pickle.dumps(columns, 1), txn=txn)

            # add the table name to the tablelist
            tablelist = pickle.loads(getattr(self.db, &quot;get_bytes&quot;,
                self.db.get) (_table_names_key, txn=txn, flags=db.DB_RMW))
            tablelist.append(table)
            # delete 1st, in case we opened with DB_DUP
            self.db.delete(_table_names_key, txn=txn)
            getattr(self.db, &quot;put_bytes&quot;, self.db.put)(_table_names_key,
                    pickle.dumps(tablelist, 1), txn=txn)

            txn.commit()
            txn = None
        except db.DBError, dberror:
            if txn:
                txn.abort()
            if sys.version_info &lt; (2, 6) :
                raise TableDBError, dberror[1]
            else :
                raise TableDBError, dberror.args[1]


    def ListTableColumns(self, table):
        &quot;&quot;&quot;Return a list of columns in the given table.
        [] if the table doesn't exist.
        &quot;&quot;&quot;
        assert isinstance(table, str)
        if contains_metastrings(table):
            raise ValueError, &quot;bad table name: contains reserved metastrings&quot;

        columnlist_key = _columns_key(table)
        if not getattr(self.db, &quot;has_key&quot;)(columnlist_key):
            return []
        pickledcolumnlist = getattr(self.db, &quot;get_bytes&quot;,
                self.db.get)(columnlist_key)
        if pickledcolumnlist:
            return pickle.loads(pickledcolumnlist)
        else:
            return []

    def ListTables(self):
        &quot;&quot;&quot;Return a list of tables in this database.&quot;&quot;&quot;
        pickledtablelist = self.db.get_get(_table_names_key)
        if pickledtablelist:
            return pickle.loads(pickledtablelist)
        else:
            return []

    def CreateOrExtendTable(self, table, columns):
        &quot;&quot;&quot;CreateOrExtendTable(table, columns)

        Create a new table in the database.

        If a table of this name already exists, extend it to have any
        additional columns present in the given list as well as
        all of its current columns.
        &quot;&quot;&quot;
        assert isinstance(columns, list)

        try:
            self.CreateTable(table, columns)
        except TableAlreadyExists:
            # the table already existed, add any new columns
            txn = None
            try:
                columnlist_key = _columns_key(table)
                txn = self.env.txn_begin()

                # load the current column list
                oldcolumnlist = pickle.loads(
                    getattr(self.db, &quot;get_bytes&quot;,
                        self.db.get)(columnlist_key, txn=txn, flags=db.DB_RMW))
                # create a hash table for fast lookups of column names in the
                # loop below
                oldcolumnhash = {}
                for c in oldcolumnlist:
                    oldcolumnhash[c] = c

                # create a new column list containing both the old and new
                # column names
                newcolumnlist = copy.copy(oldcolumnlist)
                for c in columns:
                    if not c in oldcolumnhash:
                        newcolumnlist.append(c)

                # store the table's new extended column list
                if newcolumnlist != oldcolumnlist :
                    # delete the old one first since we opened with DB_DUP
                    self.db.delete(columnlist_key, txn=txn)
                    getattr(self.db, &quot;put_bytes&quot;, self.db.put)(columnlist_key,
                                pickle.dumps(newcolumnlist, 1),
                                txn=txn)

                txn.commit()
                txn = None

                self.__load_column_info(table)
            except db.DBError, dberror:
                if txn:
                    txn.abort()
                if sys.version_info &lt; (2, 6) :
                    raise TableDBError, dberror[1]
                else :
                    raise TableDBError, dberror.args[1]


    def __load_column_info(self, table) :
        &quot;&quot;&quot;initialize the self.__tablecolumns dict&quot;&quot;&quot;
        # check the column names
        try:
            tcolpickles = getattr(self.db, &quot;get_bytes&quot;,
                    self.db.get)(_columns_key(table))
        except db.DBNotFoundError:
            raise TableDBError, &quot;unknown table: %r&quot; % (table,)
        if not tcolpickles:
            raise TableDBError, &quot;unknown table: %r&quot; % (table,)
        self.__tablecolumns[table] = pickle.loads(tcolpickles)

    def __new_rowid(self, table, txn) :
        &quot;&quot;&quot;Create a new unique row identifier&quot;&quot;&quot;
        unique = 0
        while not unique:
            # Generate a random 64-bit row ID string
            # (note: might have &lt;64 bits of true randomness
            # but it's plenty for our database id needs!)
            blist = []
            for x in xrange(_rowid_str_len):
                blist.append(random.randint(0,255))
            newid = struct.pack('B'*_rowid_str_len, *blist)

            if sys.version_info[0] &gt;= 3 :
                newid = newid.decode(&quot;iso8859-1&quot;)  # 8 bits

            # Guarantee uniqueness by adding this key to the database
            try:
                self.db.put(_rowid_key(table, newid), None, txn=txn,
                            flags=db.DB_NOOVERWRITE)
            except db.DBKeyExistError:
                pass
            else:
                unique = 1

        return newid


    def Insert(self, table, rowdict) :
        &quot;&quot;&quot;Insert(table, datadict) - Insert a new row into the table
        using the keys+values from rowdict as the column values.
        &quot;&quot;&quot;

        txn = None
        try:
            if not getattr(self.db, &quot;has_key&quot;)(_columns_key(table)):
                raise TableDBError, &quot;unknown table&quot;

            # check the validity of each column name
            if not table in self.__tablecolumns:
                self.__load_column_info(table)
            for column in rowdict.keys() :
                if not self.__tablecolumns[table].count(column):
                    raise TableDBError, &quot;unknown column: %r&quot; % (column,)

            # get a unique row identifier for this row
            txn = self.env.txn_begin()
            rowid = self.__new_rowid(table, txn=txn)

            # insert the row values into the table database
            for column, dataitem in rowdict.items():
                # store the value
                self.db.put(_data_key(table, column, rowid), dataitem, txn=txn)

            txn.commit()
            txn = None

        except db.DBError, dberror:
            # WIBNI we could just abort the txn and re-raise the exception?
            # But no, because TableDBError is not related to DBError via
            # inheritance, so it would be backwards incompatible.  Do the next
            # best thing.
            info = sys.exc_info()
            if txn:
                txn.abort()
                self.db.delete(_rowid_key(table, rowid))
            if sys.version_info &lt; (2, 6) :
                raise TableDBError, dberror[1], info[2]
            else :
                raise TableDBError, dberror.args[1], info[2]


    def Modify(self, table, conditions={}, mappings={}):
        &quot;&quot;&quot;Modify(table, conditions={}, mappings={}) - Modify items in rows matching 'conditions' using mapping functions in 'mappings'

        * table - the table name
        * conditions - a dictionary keyed on column names containing
          a condition callable expecting the data string as an
          argument and returning a boolean.
        * mappings - a dictionary keyed on column names containing a
          condition callable expecting the data string as an argument and
          returning the new string for that column.
        &quot;&quot;&quot;

        try:
            matching_rowids = self.__Select(table, [], conditions)

            # modify only requested columns
            columns = mappings.keys()
            for rowid in matching_rowids.keys():
                txn = None
                try:
                    for column in columns:
                        txn = self.env.txn_begin()
                        # modify the requested column
                        try:
                            dataitem = self.db.get(
                                _data_key(table, column, rowid),
                                txn=txn)
                            self.db.delete(
                                _data_key(table, column, rowid),
                                txn=txn)
                        except db.DBNotFoundError:
                             # XXXXXXX row key somehow didn't exist, assume no
                             # error
                            dataitem = None
                        dataitem = mappings[column](dataitem)
                        if dataitem is not None:
                            self.db.put(
                                _data_key(table, column, rowid),
                                dataitem, txn=txn)
                        txn.commit()
                        txn = None

                # catch all exceptions here since we call unknown callables
                except:
                    if txn:
                        txn.abort()
                    raise

        except db.DBError, dberror:
            if sys.version_info &lt; (2, 6) :
                raise TableDBError, dberror[1]
            else :
                raise TableDBError, dberror.args[1]

    def Delete(self, table, conditions={}):
        &quot;&quot;&quot;Delete(table, conditions) - Delete items matching the given
        conditions from the table.

        * conditions - a dictionary keyed on column names containing
          condition functions expecting the data string as an
          argument and returning a boolean.
        &quot;&quot;&quot;

        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=txn)
                        except db.DBNotFoundError:
                            # XXXXXXX column may not exist, assume no error
                            pass

                    try:
                        self.db.delete(_rowid_key(table, rowid), txn=txn)
                    except db.DBNotFoundError:
                        # XXXXXXX row key somehow didn't exist, assume no error
                        pass
                    txn.commit()
                    txn = None
                except db.DBError, dberror:
                    if txn:
                        txn.abort()
                    raise
        except db.DBError, dberror:
            if sys.version_info &lt; (2, 6) :
                raise TableDBError, dberror[1]
            else :
                raise TableDBError, dberror.args[1]


    def Select(self, table, columns, conditions={}):
        &quot;&quot;&quot;Select(table, columns, conditions) - retrieve specific row data
        Returns a list of row column-&gt;value mapping dictionaries.

        * columns - a list of which column data to return.  If
          columns is None, all columns will be returned.
        * conditions - a dictionary keyed on column names
          containing callable conditions expecting the data string as an
          argument and returning a boolean.
        &quot;&quot;&quot;
        try:
            if not table in self.__tablecolumns:
                self.__load_column_info(table)
            if columns is None:
                columns = self.__tablecolumns[table]
            matching_rowids = self.__Select(table, columns, conditions)
        except db.DBError, dberror:
            if sys.version_info &lt; (2, 6) :
                raise TableDBError, dberror[1]
            else :
                raise TableDBError, dberror.args[1]
        # return the matches as a list of dictionaries
        return matching_rowids.values()


    def __Select(self, table, columns, conditions):
        &quot;&quot;&quot;__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.
        &quot;&quot;&quot;
        # check the validity of each column name
        if not table in self.__tablecolumns:
            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, &quot;unknown column: %r&quot; % (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):

                # Needed for python 3. &quot;cmp&quot; vanished in 3.0.1
                def cmp(a, b) :
                    if a==b : return 0
                    if a&lt;b : return -1
                    return 1

                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

        if sys.version_info &lt; (2, 6) :
            conditionlist = conditions.items()
            conditionlist.sort(cmp_conditions)
        else :  # Insertion Sort. Please, improve
            conditionlist = []
            for i in conditions.items() :
                for j, k in enumerate(conditionlist) :
                    r = cmp_conditions(k, i)
                    if r == 1 :
                        conditionlist.insert(j, i)
                        break
                else :
                    conditionlist.append(i)

        # 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 rowid in rejected_rowids:
                        # if no condition was specified or the condition
                        # succeeds, add row to our match list.
                        if not condition or condition(data):
                            if not rowid in matching_rowids:
                                matching_rowids[rowid] = {}
                            if savethiscolumndata:
                                matching_rowids[rowid][column] = data
                        else:
                            if rowid in matching_rowids:
                                del matching_rowids[rowid]
                            rejected_rowids[rowid] = rowid

                    key, data = cur.next()

            except db.DBError, dberror:
                if dberror.args[0] != db.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) &gt; 0:
            for rowid, rowdata in matching_rowids.items():
                for column in columns:
                    if column in rowdata:
                        continue
                    try:
                        rowdata[column] = self.db.get(
                            _data_key(table, column, rowid))
                    except db.DBError, dberror:
                        if sys.version_info &lt; (2, 6) :
                            if dberror[0] != db.DB_NOTFOUND:
                                raise
                        else :
                            if dberror.args[0] != db.DB_NOTFOUND:
                                raise
                        rowdata[column] = None

        # return the matches
        return matching_rowids


    def Drop(self, table):
        &quot;&quot;&quot;Remove an entire table from the database&quot;&quot;&quot;
        txn = None
        try:
            txn = self.env.txn_begin()

            # delete the column list
            self.db.delete(_columns_key(table), txn=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 db.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 db.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(
                getattr(self.db, &quot;get_bytes&quot;, self.db.get)(_table_names_key,
                    txn=txn, flags=db.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=txn)
            getattr(self.db, &quot;put_bytes&quot;, self.db.put)(_table_names_key,
                    pickle.dumps(tablelist, 1), txn=txn)

            txn.commit()
            txn = None

            if table in self.__tablecolumns:
                del self.__tablecolumns[table]

        except db.DBError, dberror:
            if txn:
                txn.abort()
            raise TableDBError(dberror.args[1])
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