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author | Jack Jansen <jack.jansen@cwi.nl> | 2003-11-19 14:34:18 (GMT) |
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committer | Jack Jansen <jack.jansen@cwi.nl> | 2003-11-19 14:34:18 (GMT) |
commit | 28ecf70db57828db2ca279643bf9aeca7662f35c (patch) | |
tree | 09b7767bbc411f85313b58d6fe7e5e67d9392973 /Mac/Lib/dbmac.py | |
parent | 6045b9c93511c767f6cfa2d2fa299c76181acd9b (diff) | |
download | cpython-28ecf70db57828db2ca279643bf9aeca7662f35c.zip cpython-28ecf70db57828db2ca279643bf9aeca7662f35c.tar.gz cpython-28ecf70db57828db2ca279643bf9aeca7662f35c.tar.bz2 |
Getting rid of support for MacOS9 and earlier. This is the first step,
and the biggest in size, but probably the easiest. Hunting through the
source code comes next.
Diffstat (limited to 'Mac/Lib/dbmac.py')
-rw-r--r-- | Mac/Lib/dbmac.py | 140 |
1 files changed, 0 insertions, 140 deletions
diff --git a/Mac/Lib/dbmac.py b/Mac/Lib/dbmac.py deleted file mode 100644 index 0588dbd..0000000 --- a/Mac/Lib/dbmac.py +++ /dev/null @@ -1,140 +0,0 @@ -"""A slow but simple dbm clone for the Mac. - -For database spam, spam.dir contains the index (a text file), -spam.bak *may* contain a backup of the index (also a text file), -while spam.dat contains the data (a binary file). - -XXX TO DO: - -- reclaim free space (currently, space once occupied by deleted or expanded -items is never reused) - -- support concurrent access (currently, if two processes take turns making -updates, they can mess up the index) - -- support efficient access to large databases (currently, the whole index -is read when the database is opened, and some updates rewrite the whole index) - -- support opening for read-only (flag = 'm') - -""" - -_os = __import__('os') -import __builtin__ - -_open = __builtin__.open - -_BLOCKSIZE = 512 - -class _Database: - - def __init__(self, file): - self._dirfile = file + '.dir' - self._datfile = file + '.dat' - self._bakfile = file + '.bak' - # Mod by Jack: create data file if needed - try: - f = _open(self._datfile, 'r') - except IOError: - f = _open(self._datfile, 'w') - f.close() - self._update() - - def _update(self): - self._index = {} - try: - f = _open(self._dirfile) - except IOError: - pass - else: - while 1: - line = f.readline() - if not line: break - key, (pos, siz) = eval(line) - self._index[key] = (pos, siz) - f.close() - - def _commit(self): - try: _os.unlink(self._bakfile) - except _os.error: pass - try: _os.rename(self._dirfile, self._bakfile) - except _os.error: pass - f = _open(self._dirfile, 'w') - for key, (pos, siz) in self._index.items(): - f.write("%s, (%s, %s)\n" % (`key`, `pos`, `siz`)) - f.close() - - def __getitem__(self, key): - pos, siz = self._index[key] # may raise KeyError - f = _open(self._datfile, 'rb') - f.seek(pos) - dat = f.read(siz) - f.close() - return dat - - def _addval(self, val): - f = _open(self._datfile, 'rb+') - f.seek(0, 2) - pos = f.tell() -## Does not work under MW compiler -## pos = ((pos + _BLOCKSIZE - 1) / _BLOCKSIZE) * _BLOCKSIZE -## f.seek(pos) - npos = ((pos + _BLOCKSIZE - 1) / _BLOCKSIZE) * _BLOCKSIZE - f.write('\0'*(npos-pos)) - pos = npos - - f.write(val) - f.close() - return (pos, len(val)) - - def _setval(self, pos, val): - f = _open(self._datfile, 'rb+') - f.seek(pos) - f.write(val) - f.close() - return pos, (val) - - def _addkey(self, key, (pos, siz)): - self._index[key] = (pos, siz) - f = _open(self._dirfile, 'a') - f.write("%s, (%s, %s)\n" % (`key`, `pos`, `siz`)) - f.close() - - def __setitem__(self, key, val): - if not type(key) == type('') == type(val): - raise TypeError, "dbmac keys and values must be strings" - if not self._index.has_key(key): - (pos, siz) = self._addval(val) - self._addkey(key, (pos, siz)) - else: - pos, siz = self._index[key] - oldblocks = (siz + _BLOCKSIZE - 1) / _BLOCKSIZE - newblocks = (len(val) + _BLOCKSIZE - 1) / _BLOCKSIZE - if newblocks <= oldblocks: - pos, siz = self._setval(pos, val) - self._index[key] = pos, siz - else: - pos, siz = self._addval(val) - self._index[key] = pos, siz - self._addkey(key, (pos, siz)) - - def __delitem__(self, key): - del self._index[key] - self._commit() - - def keys(self): - return self._index.keys() - - def has_key(self, key): - return self._index.has_key(key) - - def __len__(self): - return len(self._index) - - def close(self): - self._index = self._datfile = self._dirfile = self._bakfile = None - - -def open(file, flag = None, mode = None): - # flag, mode arguments are currently ignored - return _Database(file) |