#-----------------------------------------------------------------------## 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 <greg@electricrain.com> # This provides a simple database table interface built on top of# the Python BerkeleyDB 3 interface.#_cvsid = '$Id: dbtables.py 46858 2006-06-11 08:35:14Z neal.norwitz $' import reimport sysimport copyimport xdrlibimport randomfrom types import ListType, StringTypeimport cPickle as pickle try:    # For Pythons w/distutils pybsddb    from bsddb3.db import *except ImportError:    # For Python 2.3    from bsddb.db import * # XXX(nnorwitz): is this correct? DBIncompleteError is conditional in _bsddb.ctry:    DBIncompleteErrorexcept NameError:    class DBIncompleteError(Exception):        pass class TableDBError(StandardError):    passclass TableAlreadyExists(TableDBError):    pass  class Cond:    """This condition matches everything"""    def __call__(self, s):        return 1 class ExactCond(Cond):    """Acts as an exact match condition function"""    def __init__(self, strtomatch):        self.strtomatch = strtomatch    def __call__(self, s):        return s == self.strtomatch class PrefixCond(Cond):    """Acts as a condition function for matching a string prefix"""    def __init__(self, prefix):        self.prefix = prefix    def __call__(self, s):        return s[:len(self.prefix)] == self.prefix class PostfixCond(Cond):    """Acts as a condition function for matching a string postfix"""    def __init__(self, postfix):        self.postfix = postfix    def __call__(self, s):        return s[-len(self.postfix):] == self.postfix class LikeCond(Cond):    """    Acts as a function that will match using an SQL 'LIKE' style    string.  Case insensitive and % signs are wild cards.    This isn't perfect but it should work for the simple common cases.    """    def __init__(self, likestr, re_flags=re.IGNORECASE):        # escape python re characters        chars_to_escape = '.*+()[]?'        for char in chars_to_escape :            likestr = likestr.replace(char, '\\'+char)        # convert %s to wildcards        self.likestr = likestr.replace('%', '.*')        self.re = re.compile('^'+self.likestr+'$', 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) :    """Verify that the given string does not contain any    metadata strings that might interfere with dbtables database operation.    """    if (s.find(_table_names_key) >= 0 or        s.find(_columns) >= 0 or        s.find(_data) >= 0 or        s.find(_rowid) >= 0):        # Then        return 1    else:        return 0  class bsdTableDB :    def __init__(self, filename, dbhome, create=0, truncate=0, mode=0600,                 recover=0, dbflags=0):        """bsdTableDB(filename, dbhome, create=0, truncate=0, mode=0600)         Open database name in the dbhome BerkeleyDB directory.        Use keyword arguments when calling this constructor.        """        self.db = None        myflags = DB_THREAD        if create:            myflags |= DB_CREATE        flagsforenv = (DB_INIT_MPOOL | DB_INIT_LOCK | DB_INIT_LOG |                       DB_INIT_TXN | dbflags)        # DB_AUTO_COMMIT isn't a valid flag for env.open()        try:            dbflags |= DB_AUTO_COMMIT        except AttributeError:            pass        if recover:            flagsforenv = flagsforenv | DB_RECOVER        self.env = DBEnv()        # enable auto deadlock avoidance        self.env.set_lk_detect(DB_LOCK_DEFAULT)        self.env.open(dbhome, myflags | flagsforenv)        if truncate:            myflags |= DB_TRUNCATE        self.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_DUP)        self.db.open(filename, DB_BTREE, dbflags | myflags, mode)        self.dbfilename = filename        # Initialize the table names list if this is a new database        txn = self.env.txn_begin()        try:            if not self.db.has_key(_table_names_key, txn):                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):        try:            self.env.txn_checkpoint(mins)        except DBIncompleteError:            pass     def sync(self):        try:            self.db.sync()        except DBIncompleteError:            pass     def _db_print(self) :        """Print the database to stdout for debugging"""        print "******** Printing raw database for debugging ********"        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 DBNotFoundError:            cur.close()      def CreateTable(self, table, columns):        """CreateTable(table, columns) - Create a new table in the database.         raises TableDBError if it already exists or for other DB errors.        """        assert isinstance(columns, ListType)        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(                    "bad table name: contains reserved metastrings")            for column in columns :                if contains_metastrings(column):                    raise ValueError(                        "bad column name: contains reserved metastrings")             columnlist_key = _columns_key(table)            if self.db.has_key(columnlist_key):                raise TableAlreadyExists, "table already exists"             txn = self.env.txn_begin()            # store the table's column info            self.db.put(columnlist_key, pickle.dumps(columns, 1), txn=txn)             # add the table name to the tablelist            tablelist = pickle.loads(self.db.get(_table_names_key, txn=txn,                                                 flags=DB_RMW))            tablelist.append(table)            # delete 1st, in case 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        except DBError, dberror:            if txn:                txn.abort()            raise TableDBError, dberror[1]      def ListTableColumns(self, table):        """Return a list of columns in the given table.        [] if the table doesn't exist.        """        assert isinstance(table, StringType)        if contains_metastrings(table):            raise ValueError, "bad table name: contains reserved metastrings"         columnlist_key = _columns_key(table)        if not self.db.has_key(columnlist_key):            return []        pickledcolumnlist = self.db.get(columnlist_key)        if pickledcolumnlist:            return pickle.loads(pickledcolumnlist)        else:            return []     def ListTables(self):        """Return a list of tables in this database."""        pickledtablelist = self.db.get(_table_names_key)        if pickledtablelist:            return pickle.loads(pickledtablelist)        else:            return []     def CreateOrExtendTable(self, table, columns):        """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.        """        assert isinstance(columns, ListType)        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(                    self.db.get(columnlist_key, txn=txn, flags=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 oldcolumnhash.has_key(c):                        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)                    self.db.put(columnlist_key,                                pickle.dumps(newcolumnlist, 1),                                txn=txn)                 txn.commit()                txn = None                 self.__load_column_info(table)            except DBError, dberror:                if txn:                    txn.abort()                raise TableDBError, dberror[1]      def __load_column_info(self, table) :        """initialize the self.__tablecolumns dict"""        # check the column names        try:            tcolpickles = self.db.get(_columns_key(table))        except DBNotFoundError:            raise TableDBError, "unknown table: %r" % (table,)        if not tcolpickles:            raise TableDBError, "unknown table: %r" % (table,)        self.__tablecolumns[table] = pickle.loads(tcolpickles)     def __new_rowid(self, table, txn) :        """Create a new unique row identifier"""        unique = 0        while not unique:            # Generate a random 64-bit row ID string            # (note: this code has <64 bits of randomness            # but it's plenty for our database id needs!)            p = xdrlib.Packer()            p.pack_int(int(random.random()*2147483647))            p.pack_int(int(random.random()*2147483647))            newid = p.get_buffer()             # Guarantee uniqueness by adding this key to the database            try:                self.db.put(_rowid_key(table, newid), None, txn=txn,                            flags=DB_NOOVERWRITE)            except DBKeyExistError:                pass            else:                unique = 1         return newid      def Insert(self, table, rowdict) :        """Insert(table, datadict) - Insert a new row into the table        using the keys+values from rowdict as the column values.        """        txn = None        try:            if not self.db.has_key(_columns_key(table)):                raise TableDBError, "unknown table"             # check the validity of each column name            if not self.__tablecolumns.has_key(table):                self.__load_column_info(table)            for column in rowdict.keys() :                if not self.__tablecolumns[table].count(column):                    raise TableDBError, "unknown column: %r" % (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 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))            raise TableDBError, dberror[1], info[2]      def Modify(self, table, conditions={}, mappings={}):        """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.        """        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)                            self.db.delete(                                _data_key(table, column, rowid),                                txn)                        except DBNotFoundError:                             # XXXXXXX row key somehow didn't exist, assume no                             # error                            dataitem = None                        dataitem = mappings[column](dataitem)                        if dataitem <> 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 DBError, dberror:            raise TableDBError, dberror[1]     def Delete(self, table, conditions={}):        """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.        """        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:

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