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@@ -1,154 +1,156 b'' | |||
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1 | 1 | # lock.py - simple advisory locking scheme for mercurial |
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2 | 2 | # |
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3 | 3 | # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> |
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4 | 4 | # |
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5 | 5 | # This software may be used and distributed according to the terms of the |
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6 | 6 | # GNU General Public License version 2 or any later version. |
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7 | 7 | |
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8 | 8 | import util, error |
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9 | 9 | import errno, os, socket, time |
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10 | 10 | import warnings |
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11 | 11 | |
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12 | 12 | class lock(object): |
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13 | 13 | '''An advisory lock held by one process to control access to a set |
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14 | 14 | of files. Non-cooperating processes or incorrectly written scripts |
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15 | 15 | can ignore Mercurial's locking scheme and stomp all over the |
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16 | 16 | repository, so don't do that. |
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17 | 17 | |
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18 | 18 | Typically used via localrepository.lock() to lock the repository |
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19 | 19 | store (.hg/store/) or localrepository.wlock() to lock everything |
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20 | 20 | else under .hg/.''' |
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21 | 21 | |
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22 | 22 | # lock is symlink on platforms that support it, file on others. |
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23 | 23 | |
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24 | 24 | # symlink is used because create of directory entry and contents |
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25 | 25 | # are atomic even over nfs. |
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26 | 26 | |
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27 | 27 | # old-style lock: symlink to pid |
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28 | 28 | # new-style lock: symlink to hostname:pid |
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29 | 29 | |
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30 | 30 | _host = None |
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31 | 31 | |
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32 | 32 | def __init__(self, vfs, file, timeout=-1, releasefn=None, desc=None): |
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33 | 33 | self.vfs = vfs |
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34 | 34 | self.f = file |
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35 | 35 | self.held = 0 |
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36 | 36 | self.timeout = timeout |
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37 | 37 | self.releasefn = releasefn |
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38 | 38 | self.desc = desc |
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39 | 39 | self.postrelease = [] |
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40 | 40 | self.pid = os.getpid() |
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41 | 41 | self.delay = self.lock() |
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42 | 42 | |
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43 | 43 | def __del__(self): |
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44 | 44 | if self.held: |
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45 | 45 | warnings.warn("use lock.release instead of del lock", |
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46 | 46 | category=DeprecationWarning, |
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47 | 47 | stacklevel=2) |
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48 | 48 | |
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49 | 49 | # ensure the lock will be removed |
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50 | 50 | # even if recursive locking did occur |
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51 | 51 | self.held = 1 |
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52 | 52 | |
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53 | 53 | self.release() |
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54 | 54 | |
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55 | 55 | def lock(self): |
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56 | 56 | timeout = self.timeout |
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57 | 57 | while True: |
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58 | 58 | try: |
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59 | 59 | self.trylock() |
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60 | 60 | return self.timeout - timeout |
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61 | 61 | except error.LockHeld, inst: |
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62 | 62 | if timeout != 0: |
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63 | 63 | time.sleep(1) |
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64 | 64 | if timeout > 0: |
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65 | 65 | timeout -= 1 |
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66 | 66 | continue |
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67 | 67 | raise error.LockHeld(errno.ETIMEDOUT, inst.filename, self.desc, |
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68 | 68 | inst.locker) |
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69 | 69 | |
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70 | 70 | def trylock(self): |
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71 | 71 | if self.held: |
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72 | 72 | self.held += 1 |
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73 | 73 | return |
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74 | 74 | if lock._host is None: |
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75 | 75 | lock._host = socket.gethostname() |
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76 | 76 | lockname = '%s:%s' % (lock._host, self.pid) |
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77 | 77 | while not self.held: |
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78 | 78 | try: |
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79 | 79 | self.vfs.makelock(lockname, self.f) |
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80 | 80 | self.held = 1 |
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81 | 81 | except (OSError, IOError), why: |
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82 | 82 | if why.errno == errno.EEXIST: |
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83 | 83 | locker = self.testlock() |
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84 | 84 | if locker is not None: |
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85 | 85 | raise error.LockHeld(errno.EAGAIN, |
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86 | 86 | self.vfs.join(self.f), self.desc, |
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87 | 87 | locker) |
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88 | 88 | else: |
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89 | 89 | raise error.LockUnavailable(why.errno, why.strerror, |
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90 | 90 | why.filename, self.desc) |
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91 | 91 | |
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92 | 92 | def testlock(self): |
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93 | 93 | """return id of locker if lock is valid, else None. |
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94 | 94 | |
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95 | 95 | If old-style lock, we cannot tell what machine locker is on. |
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96 | 96 | with new-style lock, if locker is on this machine, we can |
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97 | 97 | see if locker is alive. If locker is on this machine but |
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98 | 98 | not alive, we can safely break lock. |
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99 | 99 | |
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100 | 100 | The lock file is only deleted when None is returned. |
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101 | 101 | |
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102 | 102 | """ |
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103 | 103 | try: |
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104 | 104 | locker = self.vfs.readlock(self.f) |
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105 | 105 | except (OSError, IOError), why: |
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106 | 106 | if why.errno == errno.ENOENT: |
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107 | 107 | return None |
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108 | 108 | raise |
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109 | 109 | try: |
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110 | 110 | host, pid = locker.split(":", 1) |
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111 | 111 | except ValueError: |
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112 | 112 | return locker |
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113 | 113 | if host != lock._host: |
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114 | 114 | return locker |
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115 | 115 | try: |
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116 | 116 | pid = int(pid) |
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117 | 117 | except ValueError: |
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118 | 118 | return locker |
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119 | 119 | if util.testpid(pid): |
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120 | 120 | return locker |
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121 | 121 | # if locker dead, break lock. must do this with another lock |
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122 | 122 | # held, or can race and break valid lock. |
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123 | 123 | try: |
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124 | 124 | l = lock(self.vfs, self.f + '.break', timeout=0) |
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125 | 125 | self.vfs.unlink(self.f) |
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126 | 126 | l.release() |
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127 | 127 | except error.LockError: |
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128 | 128 | return locker |
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129 | 129 | |
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130 | 130 | def release(self): |
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131 | 131 | """release the lock and execute callback function if any |
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132 | 132 | |
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133 | 133 | If the lock has been acquired multiple times, the actual release is |
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134 | 134 | delayed to the last release call.""" |
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135 | 135 | if self.held > 1: |
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136 | 136 | self.held -= 1 |
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137 | 137 | elif self.held == 1: |
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138 | 138 | self.held = 0 |
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139 | 139 | if os.getpid() != self.pid: |
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140 | 140 | # we forked, and are not the parent |
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141 | 141 | return |
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142 | try: | |
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142 | 143 | if self.releasefn: |
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143 | 144 | self.releasefn() |
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145 | finally: | |
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144 | 146 | try: |
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145 | 147 | self.vfs.unlink(self.f) |
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146 | 148 | except OSError: |
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147 | 149 | pass |
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148 | 150 | for callback in self.postrelease: |
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149 | 151 | callback() |
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150 | 152 | |
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151 | 153 | def release(*locks): |
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152 | 154 | for lock in locks: |
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153 | 155 | if lock is not None: |
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154 | 156 | lock.release() |
@@ -1,41 +1,77 b'' | |||
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1 | 1 | #require unix-permissions no-root no-windows |
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2 | 2 | |
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3 | 3 | Prepare |
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4 | 4 | |
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5 | 5 | $ hg init a |
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6 | 6 | $ echo a > a/a |
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7 | 7 | $ hg -R a ci -A -m a |
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8 | 8 | adding a |
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9 | 9 | |
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10 | 10 | $ hg clone a b |
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11 | 11 | updating to branch default |
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12 | 12 | 1 files updated, 0 files merged, 0 files removed, 0 files unresolved |
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13 | 13 | |
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14 | Test that raising an exception in the release function doesn't cause the lock to choke | |
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15 | ||
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16 | $ cat > testlock.py << EOF | |
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17 | > from mercurial import cmdutil, error, util | |
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18 | > | |
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19 | > cmdtable = {} | |
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20 | > command = cmdutil.command(cmdtable) | |
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21 | > | |
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22 | > def acquiretestlock(repo, releaseexc): | |
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23 | > def unlock(): | |
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24 | > if releaseexc: | |
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25 | > raise util.Abort('expected release exception') | |
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26 | > l = repo._lock(repo.vfs, 'testlock', False, unlock, None, 'test lock') | |
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27 | > return l | |
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28 | > | |
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29 | > @command('testlockexc') | |
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30 | > def testlockexc(ui, repo): | |
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31 | > testlock = acquiretestlock(repo, True) | |
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32 | > try: | |
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33 | > testlock.release() | |
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34 | > finally: | |
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35 | > try: | |
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36 | > testlock = acquiretestlock(repo, False) | |
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37 | > except error.LockHeld: | |
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38 | > raise util.Abort('lockfile on disk even after releasing!') | |
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39 | > testlock.release() | |
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40 | > EOF | |
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41 | $ cat >> $HGRCPATH << EOF | |
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42 | > [extensions] | |
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43 | > testlock=$TESTTMP/testlock.py | |
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44 | > EOF | |
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45 | ||
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46 | $ hg -R b testlockexc | |
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47 | abort: expected release exception | |
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48 | [255] | |
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49 | ||
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14 | 50 | One process waiting for another |
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15 | 51 | |
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16 | 52 | $ cat > hooks.py << EOF |
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17 | 53 | > import time |
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18 | 54 | > def sleepone(**x): time.sleep(1) |
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19 | 55 | > def sleephalf(**x): time.sleep(0.5) |
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20 | 56 | > EOF |
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21 | 57 | $ echo b > b/b |
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22 | 58 | $ hg -R b ci -A -m b --config hooks.precommit="python:`pwd`/hooks.py:sleepone" > stdout & |
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23 | 59 | $ hg -R b up -q --config hooks.pre-update="python:`pwd`/hooks.py:sleephalf" |
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24 | 60 | waiting for lock on working directory of b held by '*:*' (glob) |
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25 | 61 | got lock after ? seconds (glob) |
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26 | 62 | warning: ignoring unknown working parent d2ae7f538514! |
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27 | 63 | $ wait |
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28 | 64 | $ cat stdout |
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29 | 65 | adding b |
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30 | 66 | |
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31 | 67 | Pushing to a local read-only repo that can't be locked |
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32 | 68 | |
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33 | 69 | $ chmod 100 a/.hg/store |
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34 | 70 | |
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35 | 71 | $ hg -R b push a |
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36 | 72 | pushing to a |
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37 | 73 | searching for changes |
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38 | 74 | abort: could not lock repository a: Permission denied |
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39 | 75 | [255] |
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40 | 76 | |
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41 | 77 | $ chmod 700 a/.hg/store |
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