Show More
@@ -1,156 +1,165 b'' | |||||
1 | # lock.py - simple advisory locking scheme for mercurial |
|
1 | # lock.py - simple advisory locking scheme for mercurial | |
2 | # |
|
2 | # | |
3 | # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> |
|
3 | # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> | |
4 | # |
|
4 | # | |
5 | # This software may be used and distributed according to the terms of the |
|
5 | # This software may be used and distributed according to the terms of the | |
6 | # GNU General Public License version 2 or any later version. |
|
6 | # GNU General Public License version 2 or any later version. | |
7 |
|
7 | |||
8 | import util, error |
|
8 | from __future__ import absolute_import | |
9 | import errno, os, socket, time |
|
9 | ||
|
10 | import errno | |||
|
11 | import os | |||
|
12 | import socket | |||
|
13 | import time | |||
10 | import warnings |
|
14 | import warnings | |
11 |
|
15 | |||
|
16 | from . import ( | |||
|
17 | error, | |||
|
18 | util, | |||
|
19 | ) | |||
|
20 | ||||
12 | class lock(object): |
|
21 | class lock(object): | |
13 | '''An advisory lock held by one process to control access to a set |
|
22 | '''An advisory lock held by one process to control access to a set | |
14 | of files. Non-cooperating processes or incorrectly written scripts |
|
23 | of files. Non-cooperating processes or incorrectly written scripts | |
15 | can ignore Mercurial's locking scheme and stomp all over the |
|
24 | can ignore Mercurial's locking scheme and stomp all over the | |
16 | repository, so don't do that. |
|
25 | repository, so don't do that. | |
17 |
|
26 | |||
18 | Typically used via localrepository.lock() to lock the repository |
|
27 | Typically used via localrepository.lock() to lock the repository | |
19 | store (.hg/store/) or localrepository.wlock() to lock everything |
|
28 | store (.hg/store/) or localrepository.wlock() to lock everything | |
20 | else under .hg/.''' |
|
29 | else under .hg/.''' | |
21 |
|
30 | |||
22 | # lock is symlink on platforms that support it, file on others. |
|
31 | # lock is symlink on platforms that support it, file on others. | |
23 |
|
32 | |||
24 | # symlink is used because create of directory entry and contents |
|
33 | # symlink is used because create of directory entry and contents | |
25 | # are atomic even over nfs. |
|
34 | # are atomic even over nfs. | |
26 |
|
35 | |||
27 | # old-style lock: symlink to pid |
|
36 | # old-style lock: symlink to pid | |
28 | # new-style lock: symlink to hostname:pid |
|
37 | # new-style lock: symlink to hostname:pid | |
29 |
|
38 | |||
30 | _host = None |
|
39 | _host = None | |
31 |
|
40 | |||
32 | def __init__(self, vfs, file, timeout=-1, releasefn=None, desc=None): |
|
41 | def __init__(self, vfs, file, timeout=-1, releasefn=None, desc=None): | |
33 | self.vfs = vfs |
|
42 | self.vfs = vfs | |
34 | self.f = file |
|
43 | self.f = file | |
35 | self.held = 0 |
|
44 | self.held = 0 | |
36 | self.timeout = timeout |
|
45 | self.timeout = timeout | |
37 | self.releasefn = releasefn |
|
46 | self.releasefn = releasefn | |
38 | self.desc = desc |
|
47 | self.desc = desc | |
39 | self.postrelease = [] |
|
48 | self.postrelease = [] | |
40 | self.pid = os.getpid() |
|
49 | self.pid = os.getpid() | |
41 | self.delay = self.lock() |
|
50 | self.delay = self.lock() | |
42 |
|
51 | |||
43 | def __del__(self): |
|
52 | def __del__(self): | |
44 | if self.held: |
|
53 | if self.held: | |
45 | warnings.warn("use lock.release instead of del lock", |
|
54 | warnings.warn("use lock.release instead of del lock", | |
46 | category=DeprecationWarning, |
|
55 | category=DeprecationWarning, | |
47 | stacklevel=2) |
|
56 | stacklevel=2) | |
48 |
|
57 | |||
49 | # ensure the lock will be removed |
|
58 | # ensure the lock will be removed | |
50 | # even if recursive locking did occur |
|
59 | # even if recursive locking did occur | |
51 | self.held = 1 |
|
60 | self.held = 1 | |
52 |
|
61 | |||
53 | self.release() |
|
62 | self.release() | |
54 |
|
63 | |||
55 | def lock(self): |
|
64 | def lock(self): | |
56 | timeout = self.timeout |
|
65 | timeout = self.timeout | |
57 | while True: |
|
66 | while True: | |
58 | try: |
|
67 | try: | |
59 | self.trylock() |
|
68 | self.trylock() | |
60 | return self.timeout - timeout |
|
69 | return self.timeout - timeout | |
61 | except error.LockHeld as inst: |
|
70 | except error.LockHeld as inst: | |
62 | if timeout != 0: |
|
71 | if timeout != 0: | |
63 | time.sleep(1) |
|
72 | time.sleep(1) | |
64 | if timeout > 0: |
|
73 | if timeout > 0: | |
65 | timeout -= 1 |
|
74 | timeout -= 1 | |
66 | continue |
|
75 | continue | |
67 | raise error.LockHeld(errno.ETIMEDOUT, inst.filename, self.desc, |
|
76 | raise error.LockHeld(errno.ETIMEDOUT, inst.filename, self.desc, | |
68 | inst.locker) |
|
77 | inst.locker) | |
69 |
|
78 | |||
70 | def trylock(self): |
|
79 | def trylock(self): | |
71 | if self.held: |
|
80 | if self.held: | |
72 | self.held += 1 |
|
81 | self.held += 1 | |
73 | return |
|
82 | return | |
74 | if lock._host is None: |
|
83 | if lock._host is None: | |
75 | lock._host = socket.gethostname() |
|
84 | lock._host = socket.gethostname() | |
76 | lockname = '%s:%s' % (lock._host, self.pid) |
|
85 | lockname = '%s:%s' % (lock._host, self.pid) | |
77 | while not self.held: |
|
86 | while not self.held: | |
78 | try: |
|
87 | try: | |
79 | self.vfs.makelock(lockname, self.f) |
|
88 | self.vfs.makelock(lockname, self.f) | |
80 | self.held = 1 |
|
89 | self.held = 1 | |
81 | except (OSError, IOError) as why: |
|
90 | except (OSError, IOError) as why: | |
82 | if why.errno == errno.EEXIST: |
|
91 | if why.errno == errno.EEXIST: | |
83 | locker = self.testlock() |
|
92 | locker = self.testlock() | |
84 | if locker is not None: |
|
93 | if locker is not None: | |
85 | raise error.LockHeld(errno.EAGAIN, |
|
94 | raise error.LockHeld(errno.EAGAIN, | |
86 | self.vfs.join(self.f), self.desc, |
|
95 | self.vfs.join(self.f), self.desc, | |
87 | locker) |
|
96 | locker) | |
88 | else: |
|
97 | else: | |
89 | raise error.LockUnavailable(why.errno, why.strerror, |
|
98 | raise error.LockUnavailable(why.errno, why.strerror, | |
90 | why.filename, self.desc) |
|
99 | why.filename, self.desc) | |
91 |
|
100 | |||
92 | def testlock(self): |
|
101 | def testlock(self): | |
93 | """return id of locker if lock is valid, else None. |
|
102 | """return id of locker if lock is valid, else None. | |
94 |
|
103 | |||
95 | If old-style lock, we cannot tell what machine locker is on. |
|
104 | If old-style lock, we cannot tell what machine locker is on. | |
96 | with new-style lock, if locker is on this machine, we can |
|
105 | with new-style lock, if locker is on this machine, we can | |
97 | see if locker is alive. If locker is on this machine but |
|
106 | see if locker is alive. If locker is on this machine but | |
98 | not alive, we can safely break lock. |
|
107 | not alive, we can safely break lock. | |
99 |
|
108 | |||
100 | The lock file is only deleted when None is returned. |
|
109 | The lock file is only deleted when None is returned. | |
101 |
|
110 | |||
102 | """ |
|
111 | """ | |
103 | try: |
|
112 | try: | |
104 | locker = self.vfs.readlock(self.f) |
|
113 | locker = self.vfs.readlock(self.f) | |
105 | except (OSError, IOError) as why: |
|
114 | except (OSError, IOError) as why: | |
106 | if why.errno == errno.ENOENT: |
|
115 | if why.errno == errno.ENOENT: | |
107 | return None |
|
116 | return None | |
108 | raise |
|
117 | raise | |
109 | try: |
|
118 | try: | |
110 | host, pid = locker.split(":", 1) |
|
119 | host, pid = locker.split(":", 1) | |
111 | except ValueError: |
|
120 | except ValueError: | |
112 | return locker |
|
121 | return locker | |
113 | if host != lock._host: |
|
122 | if host != lock._host: | |
114 | return locker |
|
123 | return locker | |
115 | try: |
|
124 | try: | |
116 | pid = int(pid) |
|
125 | pid = int(pid) | |
117 | except ValueError: |
|
126 | except ValueError: | |
118 | return locker |
|
127 | return locker | |
119 | if util.testpid(pid): |
|
128 | if util.testpid(pid): | |
120 | return locker |
|
129 | return locker | |
121 | # if locker dead, break lock. must do this with another lock |
|
130 | # if locker dead, break lock. must do this with another lock | |
122 | # held, or can race and break valid lock. |
|
131 | # held, or can race and break valid lock. | |
123 | try: |
|
132 | try: | |
124 | l = lock(self.vfs, self.f + '.break', timeout=0) |
|
133 | l = lock(self.vfs, self.f + '.break', timeout=0) | |
125 | self.vfs.unlink(self.f) |
|
134 | self.vfs.unlink(self.f) | |
126 | l.release() |
|
135 | l.release() | |
127 | except error.LockError: |
|
136 | except error.LockError: | |
128 | return locker |
|
137 | return locker | |
129 |
|
138 | |||
130 | def release(self): |
|
139 | def release(self): | |
131 | """release the lock and execute callback function if any |
|
140 | """release the lock and execute callback function if any | |
132 |
|
141 | |||
133 | If the lock has been acquired multiple times, the actual release is |
|
142 | If the lock has been acquired multiple times, the actual release is | |
134 | delayed to the last release call.""" |
|
143 | delayed to the last release call.""" | |
135 | if self.held > 1: |
|
144 | if self.held > 1: | |
136 | self.held -= 1 |
|
145 | self.held -= 1 | |
137 | elif self.held == 1: |
|
146 | elif self.held == 1: | |
138 | self.held = 0 |
|
147 | self.held = 0 | |
139 | if os.getpid() != self.pid: |
|
148 | if os.getpid() != self.pid: | |
140 | # we forked, and are not the parent |
|
149 | # we forked, and are not the parent | |
141 | return |
|
150 | return | |
142 | try: |
|
151 | try: | |
143 | if self.releasefn: |
|
152 | if self.releasefn: | |
144 | self.releasefn() |
|
153 | self.releasefn() | |
145 | finally: |
|
154 | finally: | |
146 | try: |
|
155 | try: | |
147 | self.vfs.unlink(self.f) |
|
156 | self.vfs.unlink(self.f) | |
148 | except OSError: |
|
157 | except OSError: | |
149 | pass |
|
158 | pass | |
150 | for callback in self.postrelease: |
|
159 | for callback in self.postrelease: | |
151 | callback() |
|
160 | callback() | |
152 |
|
161 | |||
153 | def release(*locks): |
|
162 | def release(*locks): | |
154 | for lock in locks: |
|
163 | for lock in locks: | |
155 | if lock is not None: |
|
164 | if lock is not None: | |
156 | lock.release() |
|
165 | lock.release() |
General Comments 0
You need to be logged in to leave comments.
Login now