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@@ -1,76 +1,77 b'' | |||||
1 | # transaction.py - simple journalling scheme for mercurial |
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1 | # transaction.py - simple journalling scheme for mercurial | |
2 | # |
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2 | # | |
3 | # This transaction scheme is intended to gracefully handle program |
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3 | # This transaction scheme is intended to gracefully handle program | |
4 | # errors and interruptions. More serious failures like system crashes |
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4 | # errors and interruptions. More serious failures like system crashes | |
5 | # can be recovered with an fsck-like tool. As the whole repository is |
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5 | # can be recovered with an fsck-like tool. As the whole repository is | |
6 | # effectively log-structured, this should amount to simply truncating |
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6 | # effectively log-structured, this should amount to simply truncating | |
7 | # anything that isn't referenced in the changelog. |
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7 | # anything that isn't referenced in the changelog. | |
8 | # |
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8 | # | |
9 | # Copyright 2005 Matt Mackall <mpm@selenic.com> |
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9 | # Copyright 2005 Matt Mackall <mpm@selenic.com> | |
10 | # |
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10 | # | |
11 | # This software may be used and distributed according to the terms |
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11 | # This software may be used and distributed according to the terms | |
12 | # of the GNU General Public License, incorporated herein by reference. |
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12 | # of the GNU General Public License, incorporated herein by reference. | |
13 |
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13 | |||
14 | import os |
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14 | import os | |
15 | import util |
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15 | import util | |
16 |
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16 | |||
17 | class transaction: |
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17 | class transaction: | |
18 | def __init__(self, opener, journal, after = None): |
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18 | def __init__(self, opener, journal, after = None): | |
19 | self.journal = None |
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19 | self.journal = None | |
20 |
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20 | |||
21 | # abort here if the journal already exists |
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21 | # abort here if the journal already exists | |
22 | if os.path.exists(journal): |
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22 | if os.path.exists(journal): | |
23 | raise "journal already exists - run hg recover" |
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23 | raise "journal already exists - run hg recover" | |
24 |
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24 | |||
25 | self.opener = opener |
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25 | self.opener = opener | |
26 | self.after = after |
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26 | self.after = after | |
27 | self.entries = [] |
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27 | self.entries = [] | |
28 | self.map = {} |
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28 | self.map = {} | |
29 | self.journal = journal |
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29 | self.journal = journal | |
30 |
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30 | |||
31 | self.file = open(self.journal, "w") |
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31 | self.file = open(self.journal, "w") | |
32 |
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32 | |||
33 | def __del__(self): |
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33 | def __del__(self): | |
34 | if self.journal: |
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34 | if self.journal: | |
35 | if self.entries: self.abort() |
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35 | if self.entries: self.abort() | |
36 | self.file.close() |
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36 | self.file.close() | |
37 | try: os.unlink(self.journal) |
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37 | try: os.unlink(self.journal) | |
38 | except: pass |
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38 | except: pass | |
39 |
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39 | |||
40 | def add(self, file, offset): |
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40 | def add(self, file, offset): | |
41 | if file in self.map: return |
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41 | if file in self.map: return | |
42 | self.entries.append((file, offset)) |
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42 | self.entries.append((file, offset)) | |
43 | self.map[file] = 1 |
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43 | self.map[file] = 1 | |
44 | # add enough data to the journal to do the truncate |
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44 | # add enough data to the journal to do the truncate | |
45 | self.file.write("%s\0%d\n" % (file, offset)) |
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45 | self.file.write("%s\0%d\n" % (file, offset)) | |
46 | self.file.flush() |
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46 | self.file.flush() | |
47 |
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47 | |||
48 | def close(self): |
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48 | def close(self): | |
49 | self.file.close() |
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49 | self.file.close() | |
50 | self.entries = [] |
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50 | self.entries = [] | |
51 | if self.after: |
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51 | if self.after: | |
52 | util.rename(self.journal, self.after) |
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52 | util.rename(self.journal, self.after) | |
53 | else: |
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53 | else: | |
54 | os.unlink(self.journal) |
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54 | os.unlink(self.journal) | |
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55 | self.journal = None | |||
55 |
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56 | |||
56 | def abort(self): |
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57 | def abort(self): | |
57 | if not self.entries: return |
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58 | if not self.entries: return | |
58 |
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59 | |||
59 | print "transaction abort!" |
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60 | print "transaction abort!" | |
60 |
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61 | |||
61 | for f, o in self.entries: |
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62 | for f, o in self.entries: | |
62 | try: |
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63 | try: | |
63 | self.opener(f, "a").truncate(o) |
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64 | self.opener(f, "a").truncate(o) | |
64 | except: |
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65 | except: | |
65 | print "failed to truncate", f |
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66 | print "failed to truncate", f | |
66 |
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67 | |||
67 | self.entries = [] |
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68 | self.entries = [] | |
68 |
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69 | |||
69 | print "rollback completed" |
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70 | print "rollback completed" | |
70 |
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71 | |||
71 | def rollback(opener, file): |
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72 | def rollback(opener, file): | |
72 | for l in open(file).readlines(): |
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73 | for l in open(file).readlines(): | |
73 | f, o = l.split('\0') |
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74 | f, o = l.split('\0') | |
74 | opener(f, "a").truncate(int(o)) |
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75 | opener(f, "a").truncate(int(o)) | |
75 | os.unlink(file) |
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76 | os.unlink(file) | |
76 |
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77 |
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