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# dblite.py module contributed by Ralf W. Grosse-Kunstleve.
# Extended for Unicode by Steven Knight.
import cPickle
import time
import shutil
import os
import types
import __builtin__
keep_all_files = 00000
ignore_corrupt_dbfiles = 0
def corruption_warning(filename):
print "Warning: Discarding corrupt database:", filename
if hasattr(types, 'UnicodeType'):
def is_string(s):
t = type(s)
return t is types.StringType or t is types.UnicodeType
else:
def is_string(s):
return type(s) is types.StringType
try:
unicode('a')
except NameError:
def unicode(s): return s
dblite_suffix = '.dblite'
tmp_suffix = '.tmp'
class dblite:
# Squirrel away references to the functions in various modules
# that we'll use when our __del__() method calls our sync() method
# during shutdown. We might get destroyed when Python is in the midst
# of tearing down the different modules we import in an essentially
# arbitrary order, and some of the various modules's global attributes
# may already be wiped out from under us.
#
# See the discussion at:
# http://mail.python.org/pipermail/python-bugs-list/2003-March/016877.html
_open = __builtin__.open
_cPickle_dump = cPickle.dump
_os_chmod = os.chmod
_os_rename = os.rename
_os_unlink = os.unlink
_shutil_copyfile = shutil.copyfile
_time_time = time.time
def __init__(self, file_base_name, flag, mode):
assert flag in (None, "r", "w", "c", "n")
if (flag is None): flag = "r"
base, ext = os.path.splitext(file_base_name)
if ext == dblite_suffix:
# There's already a suffix on the file name, don't add one.
self._file_name = file_base_name
self._tmp_name = base + tmp_suffix
else:
self._file_name = file_base_name + dblite_suffix
self._tmp_name = file_base_name + tmp_suffix
self._flag = flag
self._mode = mode
self._dict = {}
self._needs_sync = 00000
if (self._flag == "n"):
self._open(self._file_name, "wb", self._mode)
else:
try:
f = self._open(self._file_name, "rb")
except IOError, e:
if (self._flag != "c"):
raise e
self._open(self._file_name, "wb", self._mode)
else:
p = f.read()
if (len(p) > 0):
try:
self._dict = cPickle.loads(p)
except (cPickle.UnpicklingError, EOFError):
if (ignore_corrupt_dbfiles == 0): raise
if (ignore_corrupt_dbfiles == 1):
corruption_warning(self._file_name)
def __del__(self):
if (self._needs_sync):
self.sync()
def sync(self):
self._check_writable()
f = self._open(self._tmp_name, "wb", self._mode)
self._cPickle_dump(self._dict, f, 1)
f.close()
# Windows doesn't allow renaming if the file exists, so unlink
# it first, chmod'ing it to make sure we can do so. On UNIX, we
# may not be able to chmod the file if it's owned by someone else
# (e.g. from a previous run as root). We should still be able to
# unlink() the file if the directory's writable, though, so ignore
# any OSError exception thrown by the chmod() call.
try: self._os_chmod(self._file_name, 0777)
except OSError: pass
self._os_unlink(self._file_name)
self._os_rename(self._tmp_name, self._file_name)
self._needs_sync = 00000
if (keep_all_files):
self._shutil_copyfile(
self._file_name,
self._file_name + "_" + str(int(self._time_time())))
def _check_writable(self):
if (self._flag == "r"):
raise IOError("Read-only database: %s" % self._file_name)
def __getitem__(self, key):
return self._dict[key]
def __setitem__(self, key, value):
self._check_writable()
if (not is_string(key)):
raise TypeError, "key `%s' must be a string but is %s" % (key, type(key))
if (not is_string(value)):
raise TypeError, "value `%s' must be a string but is %s" % (value, type(value))
self._dict[key] = value
self._needs_sync = 0001
def keys(self):
return self._dict.keys()
def has_key(self, key):
return key in self._dict
def __contains__(self, key):
return key in self._dict
def iterkeys(self):
return self._dict.iterkeys()
__iter__ = iterkeys
def __len__(self):
return len(self._dict)
def open(file, flag=None, mode=0666):
return dblite(file, flag, mode)
def _exercise():
db = open("tmp", "n")
assert len(db) == 0
db["foo"] = "bar"
assert db["foo"] == "bar"
db[unicode("ufoo")] = unicode("ubar")
assert db[unicode("ufoo")] == unicode("ubar")
db.sync()
db = open("tmp", "c")
assert len(db) == 2, len(db)
assert db["foo"] == "bar"
db["bar"] = "foo"
assert db["bar"] == "foo"
db[unicode("ubar")] = unicode("ufoo")
assert db[unicode("ubar")] == unicode("ufoo")
db.sync()
db = open("tmp", "r")
assert len(db) == 4, len(db)
assert db["foo"] == "bar"
assert db["bar"] == "foo"
assert db[unicode("ufoo")] == unicode("ubar")
assert db[unicode("ubar")] == unicode("ufoo")
try:
db.sync()
except IOError, e:
assert str(e) == "Read-only database: tmp.dblite"
else:
raise RuntimeError, "IOError expected."
db = open("tmp", "w")
assert len(db) == 4
db["ping"] = "pong"
db.sync()
try:
db[(1,2)] = "tuple"
except TypeError, e:
assert str(e) == "key `(1, 2)' must be a string but is <type 'tuple'>", str(e)
else:
raise RuntimeError, "TypeError exception expected"
try:
db["list"] = [1,2]
except TypeError, e:
assert str(e) == "value `[1, 2]' must be a string but is <type 'list'>", str(e)
else:
raise RuntimeError, "TypeError exception expected"
db = open("tmp", "r")
assert len(db) == 5
db = open("tmp", "n")
assert len(db) == 0
_open("tmp.dblite", "w")
db = open("tmp", "r")
_open("tmp.dblite", "w").write("x")
try:
db = open("tmp", "r")
except cPickle.UnpicklingError:
pass
else:
raise RuntimeError, "cPickle exception expected."
global ignore_corrupt_dbfiles
ignore_corrupt_dbfiles = 2
db = open("tmp", "r")
assert len(db) == 0
os.unlink("tmp.dblite")
try:
db = open("tmp", "w")
except IOError, e:
assert str(e) == "[Errno 2] No such file or directory: 'tmp.dblite'", str(e)
else:
raise RuntimeError, "IOError expected."
print "OK"
if (__name__ == "__main__"):
_exercise()
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