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Diffstat (limited to 'lib/python2.7/bsddb/__init__.py')
-rw-r--r-- | lib/python2.7/bsddb/__init__.py | 455 |
1 files changed, 455 insertions, 0 deletions
diff --git a/lib/python2.7/bsddb/__init__.py b/lib/python2.7/bsddb/__init__.py new file mode 100644 index 0000000..13c9c27 --- /dev/null +++ b/lib/python2.7/bsddb/__init__.py @@ -0,0 +1,455 @@ +#---------------------------------------------------------------------- +# 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 Berkeley DB 4.3 through 5.3 with a simple interface. + +For the full featured object oriented interface use the bsddb.db module +instead. It mirrors the Oracle Berkeley DB C API. +""" + +import sys +absolute_import = (sys.version_info[0] >= 3) + +if (sys.version_info >= (2, 6)) and (sys.version_info < (3, 0)) : + import warnings + if sys.py3kwarning and (__name__ != 'bsddb3') : + warnings.warnpy3k("in 3.x, the bsddb module has been removed; " + "please use the pybsddb project instead", + DeprecationWarning, 2) + warnings.filterwarnings("ignore", ".*CObject.*", DeprecationWarning, + "bsddb.__init__") + +try: + if __name__ == 'bsddb3': + # import _pybsddb binary as it should be the more recent version from + # a standalone pybsddb addon package than the version included with + # python as bsddb._bsddb. + if absolute_import : + # Because this syntaxis is not valid before Python 2.5 + exec("from . import _pybsddb") + else : + import _pybsddb + _bsddb = _pybsddb + from bsddb3.dbutils import DeadlockWrap as _DeadlockWrap + else: + import _bsddb + from bsddb.dbutils import DeadlockWrap as _DeadlockWrap +except ImportError: + # Remove ourselves from sys.modules + import sys + del sys.modules[__name__] + raise + +# bsddb3 calls it db, but provide _db for backwards compatibility +db = _db = _bsddb +__version__ = db.__version__ + +error = db.DBError # So bsddb.error will mean something... + +#---------------------------------------------------------------------- + +import sys, os + +from weakref import ref + +if sys.version_info < (2, 6) : + import UserDict + MutableMapping = UserDict.DictMixin +else : + import collections + MutableMapping = collections.MutableMapping + +class _iter_mixin(MutableMapping): + def _make_iter_cursor(self): + cur = _DeadlockWrap(self.db.cursor) + key = id(cur) + self._cursor_refs[key] = ref(cur, self._gen_cref_cleaner(key)) + return cur + + def _gen_cref_cleaner(self, key): + # use generate the function for the weakref callback here + # to ensure that we do not hold a strict reference to cur + # in the callback. + return lambda ref: self._cursor_refs.pop(key, None) + + def __iter__(self): + self._kill_iteration = False + self._in_iter += 1 + try: + try: + cur = self._make_iter_cursor() + + # FIXME-20031102-greg: race condition. cursor could + # be closed by another thread before this call. + + # since we're only returning keys, we call the cursor + # methods with flags=0, dlen=0, dofs=0 + key = _DeadlockWrap(cur.first, 0,0,0)[0] + yield key + + next = getattr(cur, "next") + while 1: + try: + key = _DeadlockWrap(next, 0,0,0)[0] + yield key + except _bsddb.DBCursorClosedError: + if self._kill_iteration: + raise RuntimeError('Database changed size ' + 'during iteration.') + cur = self._make_iter_cursor() + # FIXME-20031101-greg: race condition. cursor could + # be closed by another thread before this call. + _DeadlockWrap(cur.set, key,0,0,0) + next = getattr(cur, "next") + except _bsddb.DBNotFoundError: + pass + except _bsddb.DBCursorClosedError: + # the database was modified during iteration. abort. + pass +# When Python 2.4 not supported in bsddb3, we can change this to "finally" + except : + self._in_iter -= 1 + raise + + self._in_iter -= 1 + + def iteritems(self): + if not self.db: + return + self._kill_iteration = False + self._in_iter += 1 + try: + try: + cur = self._make_iter_cursor() + + # FIXME-20031102-greg: race condition. cursor could + # be closed by another thread before this call. + + kv = _DeadlockWrap(cur.first) + key = kv[0] + yield kv + + next = getattr(cur, "next") + while 1: + try: + kv = _DeadlockWrap(next) + key = kv[0] + yield kv + except _bsddb.DBCursorClosedError: + if self._kill_iteration: + raise RuntimeError('Database changed size ' + 'during iteration.') + cur = self._make_iter_cursor() + # FIXME-20031101-greg: race condition. cursor could + # be closed by another thread before this call. + _DeadlockWrap(cur.set, key,0,0,0) + next = getattr(cur, "next") + except _bsddb.DBNotFoundError: + pass + except _bsddb.DBCursorClosedError: + # the database was modified during iteration. abort. + pass +# When Python 2.4 not supported in bsddb3, we can change this to "finally" + except : + self._in_iter -= 1 + raise + + self._in_iter -= 1 + + +class _DBWithCursor(_iter_mixin): + """ + 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.db.set_get_returns_none(0) + + # FIXME-20031101-greg: I believe there is still the potential + # for deadlocks in a multithreaded environment if someone + # attempts to use the any of the cursor interfaces in one + # thread while doing a put or delete in another thread. The + # reason is that _checkCursor and _closeCursors are not atomic + # operations. Doing our own locking around self.dbc, + # self.saved_dbc_key and self._cursor_refs could prevent this. + # TODO: A test case demonstrating the problem needs to be written. + + # self.dbc is a DBCursor object used to implement the + # first/next/previous/last/set_location methods. + self.dbc = None + self.saved_dbc_key = None + + # a collection of all DBCursor objects currently allocated + # by the _iter_mixin interface. + self._cursor_refs = {} + self._in_iter = 0 + self._kill_iteration = False + + def __del__(self): + self.close() + + def _checkCursor(self): + if self.dbc is None: + self.dbc = _DeadlockWrap(self.db.cursor) + if self.saved_dbc_key is not None: + _DeadlockWrap(self.dbc.set, self.saved_dbc_key) + self.saved_dbc_key = None + + # This method is needed for all non-cursor DB calls to avoid + # Berkeley DB deadlocks (due to being opened with DB_INIT_LOCK + # and DB_THREAD to be thread safe) when intermixing database + # operations that use the cursor internally with those that don't. + def _closeCursors(self, save=1): + if self.dbc: + c = self.dbc + self.dbc = None + if save: + try: + self.saved_dbc_key = _DeadlockWrap(c.current, 0,0,0)[0] + except db.DBError: + pass + _DeadlockWrap(c.close) + del c + for cref in self._cursor_refs.values(): + c = cref() + if c is not None: + _DeadlockWrap(c.close) + + 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 _DeadlockWrap(lambda: len(self.db)) # len(self.db) + + if sys.version_info >= (2, 6) : + def __repr__(self) : + if self.isOpen() : + return repr(dict(_DeadlockWrap(self.db.items))) + return repr(dict()) + + def __getitem__(self, key): + self._checkOpen() + return _DeadlockWrap(lambda: self.db[key]) # self.db[key] + + def __setitem__(self, key, value): + self._checkOpen() + self._closeCursors() + if self._in_iter and key not in self: + self._kill_iteration = True + def wrapF(): + self.db[key] = value + _DeadlockWrap(wrapF) # self.db[key] = value + + def __delitem__(self, key): + self._checkOpen() + self._closeCursors() + if self._in_iter and key in self: + self._kill_iteration = True + def wrapF(): + del self.db[key] + _DeadlockWrap(wrapF) # del self.db[key] + + def close(self): + self._closeCursors(save=0) + if self.dbc is not None: + _DeadlockWrap(self.dbc.close) + v = 0 + if self.db is not None: + v = _DeadlockWrap(self.db.close) + self.dbc = None + self.db = None + return v + + def keys(self): + self._checkOpen() + return _DeadlockWrap(self.db.keys) + + def has_key(self, key): + self._checkOpen() + return _DeadlockWrap(self.db.has_key, key) + + def set_location(self, key): + self._checkOpen() + self._checkCursor() + return _DeadlockWrap(self.dbc.set_range, key) + + def next(self): # Renamed by "2to3" + self._checkOpen() + self._checkCursor() + rv = _DeadlockWrap(getattr(self.dbc, "next")) + return rv + + if sys.version_info[0] >= 3 : # For "2to3" conversion + next = __next__ + + def previous(self): + self._checkOpen() + self._checkCursor() + rv = _DeadlockWrap(self.dbc.prev) + return rv + + def first(self): + self._checkOpen() + # fix 1725856: don't needlessly try to restore our cursor position + self.saved_dbc_key = None + self._checkCursor() + rv = _DeadlockWrap(self.dbc.first) + return rv + + def last(self): + self._checkOpen() + # fix 1725856: don't needlessly try to restore our cursor position + self.saved_dbc_key = None + self._checkCursor() + rv = _DeadlockWrap(self.dbc.last) + return rv + + def sync(self): + self._checkOpen() + return _DeadlockWrap(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, file) + e = _openDBEnv(cachesize) + d = db.DB(e) + d.set_flags(hflags) + 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, file) + e = _openDBEnv(cachesize) + d = db.DB(e) + 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, file) + e = _openDBEnv(cachesize) + d = db.DB(e) + 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 _openDBEnv(cachesize): + e = db.DBEnv() + if cachesize is not None: + if cachesize >= 20480: + e.set_cachesize(0, cachesize) + else: + raise error, "cachesize must be >= 20480" + e.set_lk_detect(db.DB_LOCK_DEFAULT) + e.open('.', db.DB_PRIVATE | db.DB_CREATE | db.DB_THREAD | db.DB_INIT_LOCK | db.DB_INIT_MPOOL) + return e + +def _checkflag(flag, file): + 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 + #flags = db.DB_CREATE | db.DB_TRUNCATE + # we used db.DB_TRUNCATE flag for this before but Berkeley DB + # 4.2.52 changed to disallowed truncate with txn environments. + if file is not None and os.path.isfile(file): + os.unlink(file) + 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 +# Berkeley DB. +# +# This assumes that if Python was built with thread support then +# Berkeley DB was too. + +try: + # 2to3 automatically changes "import thread" to "import _thread" + import thread as T + del T + +except ImportError: + db.DB_THREAD = 0 + +#---------------------------------------------------------------------- |