##// END OF EJS Templates
Fix empty transaction destruction
mpm@selenic.com -
r13:eb87b7dc default
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@@ -1,58 +1,59 b''
1 1 # transaction.py - simple journalling scheme for mercurial
2 2 #
3 3 # This transaction scheme is intended to gracefully handle program
4 4 # errors and interruptions. More serious failures like system crashes
5 5 # can be recovered with an fsck-like tool. As the whole repository is
6 6 # effectively log-structured, this should amount to simply truncating
7 7 # anything that isn't referenced in the changelog.
8 8 #
9 9 # Copyright 2005 Matt Mackall <mpm@selenic.com>
10 10 #
11 11 # This software may be used and distributed according to the terms
12 12 # of the GNU General Public License, incorporated herein by reference.
13 13
14 14 import os
15 15
16 16 class transaction:
17 17 def __init__(self, opener, journal):
18 18 self.opener = opener
19 19 self.entries = []
20 20 self.journal = journal
21 21
22 22 # abort here if the journal already exists
23 23 if os.path.exists(self.journal):
24 24 raise "Journal already exists!"
25 25 self.file = open(self.journal, "w")
26 26
27 27 def __del__(self):
28 28 if self.entries: self.abort()
29 self.close()
29 try: os.unlink(self.journal)
30 except: pass
30 31
31 32 def add(self, file, offset):
32 33 self.entries.append((file, offset))
33 34 # add enough data to the journal to do the truncate
34 35 self.file.write("%s\0%d\n" % (file, offset))
35 36 self.file.flush()
36 37
37 38 def close(self):
38 39 self.file.close()
39 40 self.entries = []
40 41 os.unlink(self.journal)
41 42
42 43 def abort(self):
43 44 if not self.entries: return
44 45
45 46 print "transaction abort!"
46 47
47 48 for f, o in self.entries:
48 49 self.opener(f, "a").truncate(o)
49 50
50 51 self.entries = []
51 52
52 53 print "rollback completed"
53 54
54 55 def recover(self):
55 56 for l in open(self.journal).readlines():
56 57 f, o = l.split('\0')
57 58 self.opener(f, "a").truncate(int(o))
58 59
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