Mercurial > cpython-lru_cache-weakref

annotate Lib/anydbm.py @ 4566:6403c94de50d legacy-trunk

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Added safeguard against failure in __del__.
author Guido van Rossum <guido@python.org>
date Wed, 27 Nov 1996 19:39:58 +0000
parents 6d762a2f9b69
children c9d0d631abaa
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1 """Generic interface to all dbm clones.
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2
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3 Instead of
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4
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5 import dbm
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6 d = dbm.open(file, 'w', 0666)
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7
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8 use
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9
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10 import anydbm
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11 d = anydbm.open(file)
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12
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13 The returned object is a dbhash, gdbm, dbm or dumbdbm object,
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14 dependent on availability of the modules (tested in this order).
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15
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16 It has the following interface (key and data are strings):
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17
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18 d[key] = data # store data at key (may override data at
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19 # existing key)
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20 data = d[key] # retrieve data at key (raise KeyError if no
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21 # such key)
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22 del d[key] # delete data stored at key (raises KeyError
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23 # if no such key)
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24 flag = d.has_key(key) # true if the key exists
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25 list = d.keys() # return a list of all existing keys (slow!)
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26
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27 Future versions may change the order in which implementations are
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28 tested for existence, add interfaces to other dbm-like
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29 implementations, and (in the presence of multiple implementations)
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30 decide which module to use based upon the extension or contents of an
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31 existing database file.
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32
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33 The open function has an optional second argument. This can be set to
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34 'r' to open the database for reading only. The default is 'r', like
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35 the dbm default.
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36
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37 """
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38
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39 _names = ['dbhash', 'gdbm', 'dbm', 'dumbdbm']
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40
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41 for _name in _names:
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42 try:
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43 exec "import %s; _mod = %s" % (_name, _name)
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44 except ImportError:
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45 continue
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46 else:
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47 break
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48 else:
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49 raise ImportError, "no dbm clone found; tried %s" % _names
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50
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51 error = _mod.error
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52
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53 def open(file, flag = 'r', mode = 0666):
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54 return _mod.open(file, flag, mode)