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authorMartin v. Löwis <martin@v.loewis.de>2002-11-19 08:09:52 (GMT)
committerMartin v. Löwis <martin@v.loewis.de>2002-11-19 08:09:52 (GMT)
commit6aa4a1f29ca575e25fc595857b2a5168a02c9780 (patch)
treeee9cce4c56b3878e5d5b5178f05f6809a19bd9c4 /Lib/bsddb/dbtables.py
parent1d2674051b5d9ad2764bb1379b06cf61974c6fdb (diff)
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Import PyBSDDB 3.4.0. Rename historical wrapper to bsddb185.
Diffstat (limited to 'Lib/bsddb/dbtables.py')
-rw-r--r--Lib/bsddb/dbtables.py629
1 files changed, 629 insertions, 0 deletions
diff --git a/Lib/bsddb/dbtables.py b/Lib/bsddb/dbtables.py
new file mode 100644
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+++ b/Lib/bsddb/dbtables.py
@@ -0,0 +1,629 @@
+#-----------------------------------------------------------------------
+#
+# Copyright (C) 2000, 2001 by Autonomous Zone Industries
+#
+# 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 = '$Id$'
+
+import string
+import sys
+try:
+ import cPickle
+ pickle = cPickle
+except ImportError:
+ import pickle
+import whrandom
+import xdrlib
+import re
+import copy
+
+from bsddb3.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 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 = string.replace(likestr, char, '\\'+char)
+ # convert %s to wildcards
+ self.likestr = string.replace(likestr, '%', '.*')
+ 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 string.find(s, _table_names_key) >= 0 or \
+ string.find(s, _columns) >= 0 or \
+ string.find(s, _data) >= 0 or \
+ string.find(s, _rowid) >= 0 :
+ 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.
+ """
+ myflags = DB_THREAD
+ if create :
+ myflags = myflags | DB_CREATE
+ flagsforenv = DB_INIT_MPOOL | DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_TXN | dbflags
+ if recover :
+ flagsforenv = flagsforenv | DB_RECOVER
+ self.env = DBEnv()
+ self.env.set_lk_detect(DB_LOCK_DEFAULT) # enable auto deadlock avoidance
+ self.env.open(dbhome, myflags | flagsforenv)
+ if truncate :
+ myflags = myflags | DB_TRUNCATE
+ self.db = DB(self.env)
+ self.db.set_flags(DB_DUP) # allow duplicate entries [warning: be careful w/ metadata]
+ self.db.open(filename, DB_BTREE, myflags, mode)
+
+ self.dbfilename = filename
+
+ # Initialize the table names list if this is a new database
+ if not self.db.has_key(_table_names_key) :
+ self.db.put(_table_names_key, pickle.dumps([], 1))
+
+ # 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 `{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 type(columns) == type([])
+ 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)
+ self.db.delete(_table_names_key, txn) # delete 1st, incase we opened with DB_DUP
+ 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 type(table) == type('')
+ 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 type(columns) == type([])
+ 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: " + `table`
+ if not tcolpickles:
+ raise TableDBError, "unknown table: " + `table`
+ self.__tablecolumns[table] = pickle.loads(tcolpickles)
+
+ def __new_rowid(self, table, txn=None) :
+ """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(whrandom.random()*2147483647))
+ p.pack_int(int(whrandom.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 DBKeyExistsError:
+ 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: "+`column`
+
+ # get a unique row identifier for this row
+ rowid = self.__new_rowid(table)
+
+ txn = self.env.txn_begin()
+
+ # 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:
+ if txn :
+ txn.abort()
+ self.db.delete(_rowid_key(table, rowid))
+ raise TableDBError, dberror[1]
+
+
+ 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:
+ dataitem = None # XXXXXXX row key somehow didn't exist, assume no error
+ 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:
+ pass # XXXXXXX column may not exist, assume no error
+
+ try:
+ self.db.delete(_rowid_key(table, rowid), txn)
+ except DBNotFoundError:
+ pass # XXXXXXX row key somehow didn't exist, assume no error
+ 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: "+`column`
+
+ # keyed on rows that match so far, containings dicts keyed on
+ # column names containing the data for that row and column.
+ matching_rowids = {}
+
+ rejected_rowids = {} # keys are rowids that do not match
+
+ # attempt to sort the conditions in such a way as to minimize full column lookups
+ def cmp_conditions(atuple, btuple):
+ a = atuple[1]
+ b = btuple[1]
+ if type(a) == type(b) :
+ if isinstance(a, PrefixCond) and isinstance(b, PrefixCond):
+ return cmp(len(b.prefix), len(a.prefix)) # longest prefix first
+ if isinstance(a, LikeCond) and isinstance(b, LikeCond):
+ return cmp(len(b.likestr), len(a.likestr)) # longest likestr first
+ 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) :
+ # only create new entries in matcing_rowids on
+ # the first pass, otherwise reject the
+ # rowid as it must not have matched
+ # the previous passes
+ if column_num == 0 :
+ if not matching_rowids.has_key(rowid) :
+ matching_rowids[rowid] = {}
+ if savethiscolumndata :
+ matching_rowids[rowid][column] = data
+ else :
+ rejected_rowids[rowid] = rowid
+ 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:
+ pass # hmm, it wasn't there, oh well, that's what we want.
+ self.db.delete(_table_names_key, txn) # delete 1st, incase we opened with DB_DUP
+ 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]
+