| #!/usr/bin/env python |
| #------------------------------------------------------------------------ |
| # Copyright (c) 1997-2001 by Total Control Software |
| # All Rights Reserved |
| #------------------------------------------------------------------------ |
| # |
| # Module Name: dbShelve.py |
| # |
| # Description: A reimplementation of the standard shelve.py that |
| # forces the use of cPickle, and DB. |
| # |
| # Creation Date: 11/3/97 3:39:04PM |
| # |
| # 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. |
| # |
| # 13-Dec-2000: Updated to be used with the new bsddb3 package. |
| # Added DBShelfCursor class. |
| # |
| #------------------------------------------------------------------------ |
| |
| """Manage shelves of pickled objects using bsddb database files for the |
| storage. |
| """ |
| |
| #------------------------------------------------------------------------ |
| |
| import sys |
| absolute_import = (sys.version_info[0] >= 3) |
| if absolute_import : |
| # Because this syntaxis is not valid before Python 2.5 |
| exec("from . import db") |
| else : |
| import db |
| |
| if sys.version_info[0] >= 3 : |
| import cPickle # Will be converted to "pickle" by "2to3" |
| else : |
| if sys.version_info < (2, 6) : |
| import cPickle |
| 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 "with" as is, because it would be invalid syntax |
| # in python 2.4 and (with no __future__) 2.5. |
| # Here we simulate "with" 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 |
| finally : |
| w.__exit__() |
| del w |
| |
| HIGHEST_PROTOCOL = cPickle.HIGHEST_PROTOCOL |
| def _dumps(object, protocol): |
| return cPickle.dumps(object, protocol=protocol) |
| |
| if sys.version_info < (2, 6) : |
| from UserDict import DictMixin as MutableMapping |
| else : |
| import collections |
| MutableMapping = collections.MutableMapping |
| |
| #------------------------------------------------------------------------ |
| |
| |
| def open(filename, flags=db.DB_CREATE, mode=0660, filetype=db.DB_HASH, |
| dbenv=None, dbname=None): |
| """ |
| A simple factory function for compatibility with the standard |
| shleve.py module. It can be used like this, where key is a string |
| and data is a pickleable object: |
| |
| from bsddb import dbshelve |
| db = dbshelve.open(filename) |
| |
| db[key] = data |
| |
| db.close() |
| """ |
| if type(flags) == type(''): |
| sflag = flags |
| if sflag == 'r': |
| flags = db.DB_RDONLY |
| elif sflag == 'rw': |
| flags = 0 |
| elif sflag == 'w': |
| flags = db.DB_CREATE |
| elif sflag == 'c': |
| flags = db.DB_CREATE |
| elif sflag == 'n': |
| flags = db.DB_TRUNCATE | db.DB_CREATE |
| else: |
| raise db.DBError, "flags should be one of 'r', 'w', 'c' or 'n' or use the bsddb.db.DB_* flags" |
| |
| d = DBShelf(dbenv) |
| d.open(filename, dbname, filetype, flags, mode) |
| return d |
| |
| #--------------------------------------------------------------------------- |
| |
| class DBShelveError(db.DBError): pass |
| |
| |
| class DBShelf(MutableMapping): |
| """A shelf to hold pickled objects, built upon a bsddb DB object. It |
| automatically pickles/unpickles data objects going to/from the DB. |
| """ |
| def __init__(self, dbenv=None): |
| self.db = db.DB(dbenv) |
| self._closed = True |
| if HIGHEST_PROTOCOL: |
| self.protocol = HIGHEST_PROTOCOL |
| else: |
| self.protocol = 1 |
| |
| |
| def __del__(self): |
| self.close() |
| |
| |
| def __getattr__(self, name): |
| """Many methods we can just pass through to the DB object. |
| (See below) |
| """ |
| return getattr(self.db, name) |
| |
| |
| #----------------------------------- |
| # Dictionary access methods |
| |
| def __len__(self): |
| return len(self.db) |
| |
| |
| def __getitem__(self, key): |
| data = self.db[key] |
| return cPickle.loads(data) |
| |
| |
| def __setitem__(self, key, value): |
| data = _dumps(value, self.protocol) |
| self.db[key] = data |
| |
| |
| def __delitem__(self, key): |
| del self.db[key] |
| |
| |
| def keys(self, txn=None): |
| if txn is not None: |
| return self.db.keys(txn) |
| else: |
| return self.db.keys() |
| |
| if sys.version_info >= (2, 6) : |
| def __iter__(self) : # XXX: Load all keys in memory :-( |
| for k in self.db.keys() : |
| yield k |
| |
| # Do this when "DB" support iteration |
| # Or is it enough to pass thru "getattr"? |
| # |
| # def __iter__(self) : |
| # return self.db.__iter__() |
| |
| |
| def open(self, *args, **kwargs): |
| self.db.open(*args, **kwargs) |
| self._closed = False |
| |
| |
| def close(self, *args, **kwargs): |
| self.db.close(*args, **kwargs) |
| self._closed = True |
| |
| |
| def __repr__(self): |
| if self._closed: |
| return '<DBShelf @ 0x%x - closed>' % (id(self)) |
| else: |
| return repr(dict(self.iteritems())) |
| |
| |
| def items(self, txn=None): |
| if txn is not None: |
| items = self.db.items(txn) |
| else: |
| items = self.db.items() |
| newitems = [] |
| |
| for k, v in items: |
| newitems.append( (k, cPickle.loads(v)) ) |
| return newitems |
| |
| def values(self, txn=None): |
| if txn is not None: |
| values = self.db.values(txn) |
| else: |
| values = self.db.values() |
| |
| return map(cPickle.loads, values) |
| |
| #----------------------------------- |
| # Other methods |
| |
| def __append(self, value, txn=None): |
| data = _dumps(value, self.protocol) |
| return self.db.append(data, txn) |
| |
| def append(self, value, txn=None): |
| if self.get_type() == db.DB_RECNO: |
| return self.__append(value, txn=txn) |
| raise DBShelveError, "append() only supported when dbshelve opened with filetype=dbshelve.db.DB_RECNO" |
| |
| |
| def associate(self, secondaryDB, callback, flags=0): |
| def _shelf_callback(priKey, priData, realCallback=callback): |
| # Safe in Python 2.x because expresion short circuit |
| if sys.version_info[0] < 3 or isinstance(priData, bytes) : |
| data = cPickle.loads(priData) |
| else : |
| data = cPickle.loads(bytes(priData, "iso8859-1")) # 8 bits |
| return realCallback(priKey, data) |
| |
| return self.db.associate(secondaryDB, _shelf_callback, flags) |
| |
| |
| #def get(self, key, default=None, txn=None, flags=0): |
| def get(self, *args, **kw): |
| # We do it with *args and **kw so if the default value wasn't |
| # given nothing is passed to the extension module. That way |
| # an exception can be raised if set_get_returns_none is turned |
| # off. |
| data = self.db.get(*args, **kw) |
| try: |
| return cPickle.loads(data) |
| except (EOFError, TypeError, cPickle.UnpicklingError): |
| return data # we may be getting the default value, or None, |
| # so it doesn't need unpickled. |
| |
| def get_both(self, key, value, txn=None, flags=0): |
| data = _dumps(value, self.protocol) |
| data = self.db.get(key, data, txn, flags) |
| return cPickle.loads(data) |
| |
| |
| def cursor(self, txn=None, flags=0): |
| c = DBShelfCursor(self.db.cursor(txn, flags)) |
| c.protocol = self.protocol |
| return c |
| |
| |
| def put(self, key, value, txn=None, flags=0): |
| data = _dumps(value, self.protocol) |
| return self.db.put(key, data, txn, flags) |
| |
| |
| def join(self, cursorList, flags=0): |
| raise NotImplementedError |
| |
| |
| #---------------------------------------------- |
| # Methods allowed to pass-through to self.db |
| # |
| # close, delete, fd, get_byteswapped, get_type, has_key, |
| # key_range, open, remove, rename, stat, sync, |
| # upgrade, verify, and all set_* methods. |
| |
| |
| #--------------------------------------------------------------------------- |
| |
| class DBShelfCursor: |
| """ |
| """ |
| def __init__(self, cursor): |
| self.dbc = cursor |
| |
| def __del__(self): |
| self.close() |
| |
| |
| def __getattr__(self, name): |
| """Some methods we can just pass through to the cursor object. (See below)""" |
| return getattr(self.dbc, name) |
| |
| |
| #---------------------------------------------- |
| |
| def dup(self, flags=0): |
| c = DBShelfCursor(self.dbc.dup(flags)) |
| c.protocol = self.protocol |
| return c |
| |
| |
| def put(self, key, value, flags=0): |
| data = _dumps(value, self.protocol) |
| return self.dbc.put(key, data, flags) |
| |
| |
| def get(self, *args): |
| count = len(args) # a method overloading hack |
| method = getattr(self, 'get_%d' % count) |
| method(*args) |
| |
| def get_1(self, flags): |
| rec = self.dbc.get(flags) |
| return self._extract(rec) |
| |
| def get_2(self, key, flags): |
| rec = self.dbc.get(key, flags) |
| return self._extract(rec) |
| |
| def get_3(self, key, value, flags): |
| data = _dumps(value, self.protocol) |
| rec = self.dbc.get(key, flags) |
| return self._extract(rec) |
| |
| |
| def current(self, flags=0): return self.get_1(flags|db.DB_CURRENT) |
| def first(self, flags=0): return self.get_1(flags|db.DB_FIRST) |
| def last(self, flags=0): return self.get_1(flags|db.DB_LAST) |
| def next(self, flags=0): return self.get_1(flags|db.DB_NEXT) |
| def prev(self, flags=0): return self.get_1(flags|db.DB_PREV) |
| def consume(self, flags=0): return self.get_1(flags|db.DB_CONSUME) |
| def next_dup(self, flags=0): return self.get_1(flags|db.DB_NEXT_DUP) |
| def next_nodup(self, flags=0): return self.get_1(flags|db.DB_NEXT_NODUP) |
| def prev_nodup(self, flags=0): return self.get_1(flags|db.DB_PREV_NODUP) |
| |
| |
| def get_both(self, key, value, flags=0): |
| data = _dumps(value, self.protocol) |
| rec = self.dbc.get_both(key, flags) |
| return self._extract(rec) |
| |
| |
| def set(self, key, flags=0): |
| rec = self.dbc.set(key, flags) |
| return self._extract(rec) |
| |
| def set_range(self, key, flags=0): |
| rec = self.dbc.set_range(key, flags) |
| return self._extract(rec) |
| |
| def set_recno(self, recno, flags=0): |
| rec = self.dbc.set_recno(recno, flags) |
| return self._extract(rec) |
| |
| set_both = get_both |
| |
| def _extract(self, rec): |
| if rec is None: |
| return None |
| else: |
| key, data = rec |
| # Safe in Python 2.x because expresion short circuit |
| if sys.version_info[0] < 3 or isinstance(data, bytes) : |
| return key, cPickle.loads(data) |
| else : |
| return key, cPickle.loads(bytes(data, "iso8859-1")) # 8 bits |
| |
| #---------------------------------------------- |
| # Methods allowed to pass-through to self.dbc |
| # |
| # close, count, delete, get_recno, join_item |
| |
| |
| #--------------------------------------------------------------------------- |
