[ditrack commit] r1628 - src/trunk/DITrack/Util

[Vlad Skvortsov]

Hey Ivan,

can you please announce when you are done with the lower level locking 
stuff? I'd like to review it looking at the whole picture.


gli at ditrack.org wrote:
> Author: gli
> Date: 2007-05-22 07:33:11 -0700 (Tue, 22 May 2007)
> New Revision: 1628
>
> Modified:
>    src/trunk/DITrack/Util/Locking.py
> Log:
> Use current lock()/unlock() functions only to "posix" systems. Do nothing for "nt".
>
> Modified: src/trunk/DITrack/Util/Locking.py
> ===================================================================
> --- src/trunk/DITrack/Util/Locking.py	2007-05-22 14:08:10 UTC (rev 1627)
> +++ src/trunk/DITrack/Util/Locking.py	2007-05-22 14:33:11 UTC (rev 1628)
> @@ -29,7 +29,8 @@
>  #
>  
>  import os
> -import fcntl
> +if os.name == "posix":
> +    import fcntl
>  
>  import DITrack.DB.Common
>  
> @@ -58,37 +59,41 @@
>  
>      lock_fname = os.path.join(datadir, DITrack.DB.Common.LOCK_FILE)
>  
> -    if not os.path.exists(lock_fname):
> -        # if there's no lock file - create it and lock it
> +    if os.name == "posix":
> +        if not os.path.exists(lock_fname):
> +            # if there's no lock file - create it and lock it
> +            try:
> +                fd = open (lock_fname, "w")
> +                fcntl.flock(fd.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
> +            except IOError, (errid, strerror):
> +                DITrack.Util.common.err("Can't lock file %s: %s" % 
> +                    (lock_fname, strerror))
> +            fd.write(repr(os.getpid()))
> +            fd.flush()
> +            return fd
> +        # else if file exists
>          try:
> -            fd = open (lock_fname, "w")
> +            fd = open (lock_fname, "r")
>              fcntl.flock(fd.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
> -        except IOError, (errid, strerror):
> -            DITrack.Util.common.err("Can't lock file %s: %s" % 
> -                (lock_fname, strerror))
> -        fd.write(repr(os.getpid()))
> -        fd.flush()
> -        return fd
> -    # else if file exists
> -    try:
> -        fd = open (lock_fname, "r")
> -        fcntl.flock(fd.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
> -    except IOError, (err, strerror):
> -        if ((err == errno.EACCES) or (err == errno.EAGAIN)):
> -            # Lock on file conent exists
> -            pid = open(lock_fname, "r").readline().strip()
> -            if not pid.isdigit():
> -                raise DITrack.DB.Exceptions.DBLockFileCorruptedError
> -            # lockfile exists, but is corrupted
> -            raise DITrack.DB.Exceptions.DBIsLockedError(pid)
> +        except IOError, (err, strerror):
> +            if ((err == errno.EACCES) or (err == errno.EAGAIN)):
> +                # Lock on file conent exists
> +                pid = open(lock_fname, "r").readline().strip()
> +                if not pid.isdigit():
> +                    raise DITrack.DB.Exceptions.DBLockFileCorruptedError
> +                # lockfile exists, but is corrupted
> +                raise DITrack.DB.Exceptions.DBIsLockedError(pid)
> +            else:
> +                raise
>          else:
> -            raise
> +            raise DITrack.DB.Exceptions.DBStaleLockError
>      else:
> -        raise DITrack.DB.Exceptions.DBStaleLockError
> +        return None
>  
>  def unlock(lockfd):
> -    # if database path is wrong, object doesn't have lockfd attribute
> -    if lockfd:
> -        fcntl.flock(lockfd.fileno(), fcntl.LOCK_UN)
> -        os.unlink(lockfd.name)
> +    if os.name == "posix":
> +        # if database path is wrong, object doesn't have lockfd attribute
> +        if lockfd:
> +            fcntl.flock(lockfd.fileno(), fcntl.LOCK_UN)
> +            os.unlink(lockfd.name)
>  
>
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>   



-- 
Vlad Skvortsov, vss at 73rus.com, http://vss.73rus.com