Initial commit of OpenSPARC T2 architecture model.

[OpenSPARC-T2-SAM] / sam-t2 / devtools / v9 / lib / python2.4 / bsddb / dbtables.py

#-----------------------------------------------------------------------
#
# 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,v 1.11 2004/08/08 00:54:20 tim_one Exp $'

import re
import sys
import copy
import xdrlib
import random
from types import ListType, StringType
import cPickle as pickle

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


class TableDBError(StandardError):
   pass
class 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.open(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) - Modify in rows matching 'conditions'
       using mapping functions in 'mappings'
       * conditions is a dictionary keyed on column names
       containing condition functions expecting the data string as an
       argument and returning a boolean.
       * mappings is a dictionary keyed on column names containint condition
       functions 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

               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]