cpython/Lib/bsddb/__init__.py

238 lines
7.0 KiB
Python

#----------------------------------------------------------------------
# Copyright (c) 1999-2001, Digital Creations, Fredericksburg, VA, USA
# and Andrew Kuchling. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# o Redistributions of source code must retain the above copyright
# notice, this list of conditions, and the disclaimer that follows.
#
# o Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions, and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
#
# o Neither the name of Digital Creations nor the names of its
# contributors may be used to endorse or promote products derived
# from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY DIGITAL CREATIONS AND CONTRIBUTORS *AS
# IS* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DIGITAL
# CREATIONS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
# TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
# DAMAGE.
#----------------------------------------------------------------------
"""Support for BerkeleyDB 3.1 through 4.1.
"""
try:
import _bsddb
except ImportError:
# Remove ourselves from sys.modules
import sys
del sys.modules[__name__]
raise
# bsddb3 calls it _db
_db = _bsddb
__version__ = _db.__version__
error = _db.DBError # So bsddb.error will mean something...
#----------------------------------------------------------------------
class _DBWithCursor:
"""
A simple wrapper around DB that makes it look like the bsddbobject in
the old module. It uses a cursor as needed to provide DB traversal.
"""
def __init__(self, db):
self.db = db
self.dbc = None
self.db.set_get_returns_none(0)
def __del__(self):
self.close()
def _checkCursor(self):
if self.dbc is None:
self.dbc = self.db.cursor()
def _checkOpen(self):
if self.db is None:
raise error, "BSDDB object has already been closed"
def isOpen(self):
return self.db is not None
def __len__(self):
self._checkOpen()
return len(self.db)
def __getitem__(self, key):
self._checkOpen()
return self.db[key]
def __setitem__(self, key, value):
self._checkOpen()
self.db[key] = value
def __delitem__(self, key):
self._checkOpen()
del self.db[key]
def close(self):
if self.dbc is not None:
self.dbc.close()
v = 0
if self.db is not None:
v = self.db.close()
self.dbc = None
self.db = None
return v
def keys(self):
self._checkOpen()
return self.db.keys()
def has_key(self, key):
self._checkOpen()
return self.db.has_key(key)
def set_location(self, key):
self._checkOpen()
self._checkCursor()
return self.dbc.set(key)
def next(self):
self._checkOpen()
self._checkCursor()
rv = self.dbc.next()
return rv
def previous(self):
self._checkOpen()
self._checkCursor()
rv = self.dbc.prev()
return rv
def first(self):
self._checkOpen()
self._checkCursor()
rv = self.dbc.first()
return rv
def last(self):
self._checkOpen()
self._checkCursor()
rv = self.dbc.last()
return rv
def sync(self):
self._checkOpen()
return self.db.sync()
#----------------------------------------------------------------------
# Compatibility object factory functions
def hashopen(file, flag='c', mode=0666, pgsize=None, ffactor=None, nelem=None,
cachesize=None, lorder=None, hflags=0):
flags = _checkflag(flag)
d = _db.DB()
d.set_flags(hflags)
if cachesize is not None: d.set_cachesize(0, cachesize)
if pgsize is not None: d.set_pagesize(pgsize)
if lorder is not None: d.set_lorder(lorder)
if ffactor is not None: d.set_h_ffactor(ffactor)
if nelem is not None: d.set_h_nelem(nelem)
d.open(file, _db.DB_HASH, flags, mode)
return _DBWithCursor(d)
#----------------------------------------------------------------------
def btopen(file, flag='c', mode=0666,
btflags=0, cachesize=None, maxkeypage=None, minkeypage=None,
pgsize=None, lorder=None):
flags = _checkflag(flag)
d = _db.DB()
if cachesize is not None: d.set_cachesize(0, cachesize)
if pgsize is not None: d.set_pagesize(pgsize)
if lorder is not None: d.set_lorder(lorder)
d.set_flags(btflags)
if minkeypage is not None: d.set_bt_minkey(minkeypage)
if maxkeypage is not None: d.set_bt_maxkey(maxkeypage)
d.open(file, _db.DB_BTREE, flags, mode)
return _DBWithCursor(d)
#----------------------------------------------------------------------
def rnopen(file, flag='c', mode=0666,
rnflags=0, cachesize=None, pgsize=None, lorder=None,
rlen=None, delim=None, source=None, pad=None):
flags = _checkflag(flag)
d = _db.DB()
if cachesize is not None: d.set_cachesize(0, cachesize)
if pgsize is not None: d.set_pagesize(pgsize)
if lorder is not None: d.set_lorder(lorder)
d.set_flags(rnflags)
if delim is not None: d.set_re_delim(delim)
if rlen is not None: d.set_re_len(rlen)
if source is not None: d.set_re_source(source)
if pad is not None: d.set_re_pad(pad)
d.open(file, _db.DB_RECNO, flags, mode)
return _DBWithCursor(d)
#----------------------------------------------------------------------
def _checkflag(flag):
if flag == 'r':
flags = _db.DB_RDONLY
elif flag == 'rw':
flags = 0
elif flag == 'w':
flags = _db.DB_CREATE
elif flag == 'c':
flags = _db.DB_CREATE
elif flag == 'n':
flags = _db.DB_CREATE | _db.DB_TRUNCATE
else:
raise error, "flags should be one of 'r', 'w', 'c' or 'n'"
return flags | _db.DB_THREAD
#----------------------------------------------------------------------
# This is a silly little hack that allows apps to continue to use the
# DB_THREAD flag even on systems without threads without freaking out
# BerkeleyDB.
#
# This assumes that if Python was built with thread support then
# BerkeleyDB was too.
try:
import thread
del thread
except ImportError:
_db.DB_THREAD = 0
#----------------------------------------------------------------------