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0de65807e6
also modified check_all function to suppress all warnings since they aren't relevant to what this test is doing (allows quiet checking of regsub, for instance)
159 lines
4.4 KiB
Python
159 lines
4.4 KiB
Python
"""Manage shelves of pickled objects.
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A "shelf" is a persistent, dictionary-like object. The difference
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with dbm databases is that the values (not the keys!) in a shelf can
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be essentially arbitrary Python objects -- anything that the "pickle"
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module can handle. This includes most class instances, recursive data
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types, and objects containing lots of shared sub-objects. The keys
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are ordinary strings.
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To summarize the interface (key is a string, data is an arbitrary
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object):
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import shelve
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d = shelve.open(filename) # open, with (g)dbm filename -- no suffix
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d[key] = data # store data at key (overwrites old data if
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# using an existing key)
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data = d[key] # retrieve data at key (raise KeyError if no
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# such key)
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del d[key] # delete data stored at key (raises KeyError
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# if no such key)
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flag = d.has_key(key) # true if the key exists
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list = d.keys() # a list of all existing keys (slow!)
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d.close() # close it
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Dependent on the implementation, closing a persistent dictionary may
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or may not be necessary to flush changes to disk.
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"""
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# Try using cPickle and cStringIO if available.
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try:
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from cPickle import Pickler, Unpickler
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except ImportError:
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from pickle import Pickler, Unpickler
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try:
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from cStringIO import StringIO
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except ImportError:
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from StringIO import StringIO
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__all__ = ["Shelf","BsdDbShelf","DbfilenameShelf","open"]
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class Shelf:
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"""Base class for shelf implementations.
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This is initialized with a dictionary-like object.
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See the module's __doc__ string for an overview of the interface.
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"""
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def __init__(self, dict):
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self.dict = dict
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def keys(self):
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return self.dict.keys()
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def __len__(self):
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return len(self.dict)
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def has_key(self, key):
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return self.dict.has_key(key)
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def get(self, key, default=None):
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if self.dict.has_key(key):
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return self[key]
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return default
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def __getitem__(self, key):
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f = StringIO(self.dict[key])
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return Unpickler(f).load()
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def __setitem__(self, key, value):
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f = StringIO()
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p = Pickler(f)
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p.dump(value)
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self.dict[key] = f.getvalue()
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def __delitem__(self, key):
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del self.dict[key]
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def close(self):
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try:
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self.dict.close()
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except:
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pass
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self.dict = 0
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def __del__(self):
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self.close()
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def sync(self):
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if hasattr(self.dict, 'sync'):
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self.dict.sync()
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class BsdDbShelf(Shelf):
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"""Shelf implementation using the "BSD" db interface.
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This adds methods first(), next(), previous(), last() and
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set_location() that have no counterpart in [g]dbm databases.
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The actual database must be opened using one of the "bsddb"
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modules "open" routines (i.e. bsddb.hashopen, bsddb.btopen or
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bsddb.rnopen) and passed to the constructor.
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See the module's __doc__ string for an overview of the interface.
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"""
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def __init__(self, dict):
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Shelf.__init__(self, dict)
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def set_location(self, key):
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(key, value) = self.dict.set_location(key)
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f = StringIO(value)
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return (key, Unpickler(f).load())
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def next(self):
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(key, value) = self.dict.next()
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f = StringIO(value)
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return (key, Unpickler(f).load())
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def previous(self):
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(key, value) = self.dict.previous()
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f = StringIO(value)
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return (key, Unpickler(f).load())
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def first(self):
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(key, value) = self.dict.first()
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f = StringIO(value)
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return (key, Unpickler(f).load())
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def last(self):
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(key, value) = self.dict.last()
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f = StringIO(value)
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return (key, Unpickler(f).load())
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class DbfilenameShelf(Shelf):
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"""Shelf implementation using the "anydbm" generic dbm interface.
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This is initialized with the filename for the dbm database.
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See the module's __doc__ string for an overview of the interface.
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"""
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def __init__(self, filename, flag='c'):
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import anydbm
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Shelf.__init__(self, anydbm.open(filename, flag))
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def open(filename, flag='c'):
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"""Open a persistent dictionary for reading and writing.
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Argument is the filename for the dbm database.
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See the module's __doc__ string for an overview of the interface.
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"""
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return DbfilenameShelf(filename, flag)
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