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mercurial/lock.py
changeset 2016 ff5c9a92f556
parent 1877 d314a89fa4f1
child 2579 0875cda033fd
equal deleted inserted replaced
2009:182f500805db 2016:ff5c9a92f556 
     6 # of the GNU General Public License, incorporated herein by reference.
 
     6 # of the GNU General Public License, incorporated herein by reference.
 
     7 
     7 
     8 from demandload import *
 
     8 from demandload import *
 
     9 demandload(globals(), 'errno os socket time util')
 
     9 demandload(globals(), 'errno os socket time util')
 
    10 
    10 
    11 class LockException(Exception):
 
    11 class LockException(IOError):
 
    12     pass
 
    12     def __init__(self, errno, strerror, filename, desc):
 
       
    13         IOError.__init__(self, errno, strerror, filename)
 
       
    14         self.desc = desc
 
       
    15 
    13 class LockHeld(LockException):
 
    16 class LockHeld(LockException):
 
    14     pass
 
    17     def __init__(self, errno, filename, desc, locker):
 
       
    18         LockException.__init__(self, errno, 'Lock held', filename, desc)
 
       
    19         self.locker = locker
 
       
    20 
    15 class LockUnavailable(LockException):
 
    21 class LockUnavailable(LockException):
 
    16     pass
 
    22     pass
 
    17 
    23 
    18 class lock(object):
 
    24 class lock(object):
 
    19     # lock is symlink on platforms that support it, file on others.
 
    25     # lock is symlink on platforms that support it, file on others.
 
    22     # are atomic even over nfs.
 
    28     # are atomic even over nfs.
 
    23 
    29 
    24     # old-style lock: symlink to pid
 
    30     # old-style lock: symlink to pid
 
    25     # new-style lock: symlink to hostname:pid
 
    31     # new-style lock: symlink to hostname:pid
 
    26 
    32 
    27     def __init__(self, file, timeout=-1, releasefn=None):
 
    33     def __init__(self, file, timeout=-1, releasefn=None, desc=None):
 
    28         self.f = file
 
    34         self.f = file
 
    29         self.held = 0
 
    35         self.held = 0
 
    30         self.timeout = timeout
 
    36         self.timeout = timeout
 
    31         self.releasefn = releasefn
 
    37         self.releasefn = releasefn
 
    32         self.id = None
 
    38         self.id = None
 
    33         self.host = None
 
    39         self.host = None
 
    34         self.pid = None
 
    40         self.pid = None
 
       
    41         self.desc = desc
 
    35         self.lock()
 
    42         self.lock()
 
    36 
    43 
    37     def __del__(self):
 
    44     def __del__(self):
 
    38         self.release()
 
    45         self.release()
 
    39 
    46 
    47                 if timeout != 0:
 
    54                 if timeout != 0:
 
    48                     time.sleep(1)
 
    55                     time.sleep(1)
 
    49                     if timeout > 0:
 
    56                     if timeout > 0:
 
    50                         timeout -= 1
 
    57                         timeout -= 1
 
    51                     continue
 
    58                     continue
 
    52                 raise inst
 
    59                 raise LockHeld(errno.ETIMEDOUT, inst.filename, self.desc,
 
       
    60                                inst.locker)
 
    53 
    61 
    54     def trylock(self):
 
    62     def trylock(self):
 
    55         if self.id is None:
 
    63         if self.id is None:
 
    56             self.host = socket.gethostname()
 
    64             self.host = socket.gethostname()
 
    57             self.pid = os.getpid()
 
    65             self.pid = os.getpid()
 
    62                 self.held = 1
 
    70                 self.held = 1
 
    63             except (OSError, IOError), why:
 
    71             except (OSError, IOError), why:
 
    64                 if why.errno == errno.EEXIST:
 
    72                 if why.errno == errno.EEXIST:
 
    65                     locker = self.testlock()
 
    73                     locker = self.testlock()
 
    66                     if locker:
 
    74                     if locker:
 
    67                         raise LockHeld(locker)
 
    75                         raise LockHeld(errno.EAGAIN, self.f, self.desc,
 
       
    76                                        locker)
 
    68                 else:
 
    77                 else:
 
    69                     raise LockUnavailable(why)
 
    78                     raise LockUnavailable(why.errno, why.strerror,
 
       
    79                                           why.filename, self.desc)
 
    70 
    80 
    71     def testlock(self):
 
    81     def testlock(self):
 
    72         '''return id of locker if lock is valid, else None.'''
 
    82         '''return id of locker if lock is valid, else None.'''
 
    73         # if old-style lock, we cannot tell what machine locker is on.
 
    83         # if old-style lock, we cannot tell what machine locker is on.
 
    74         # with new-style lock, if locker is on this machine, we can
 
    84         # with new-style lock, if locker is on this machine, we can
mercurial-crew-with-dirclash