locker Namespace Reference

Classes
class	LockFile
	Lock a file. More...
Functions
def	lock
def	unlock
def	_tmpFileName
def	_lckFileName
def	_linkCount
def	_read
def	_sleep
Variables
	LOCK_EX = fcntl.F_WRLCK
	LOCK_SH = fcntl.F_RDLCK
	LOCK_NB = fcntl.F_UNLCK

---

Function Documentation

def locker::_lckFileName

(

fileName )

[private]

Definition at line 51 of file locker.py.

                              :
        return "%s.lock" % fileName

def locker::_linkCount

(

lockFileName )

[private]

Definition at line 54 of file locker.py.

00055                                   :
00056         try:
00057             return os.stat(lockFileName).st_nlink
00058         except OSError, e:
00059             if e.errno != errno.ENOENT:
00060                 raise
            return -1

def locker::_read

(

fileName )

[private]

Definition at line 61 of file locker.py.

00062                        :
00063         try:
00064             fp = open(fileName)
00065             try:     readFileName = fp.read()
00066             finally: fp.close()
00067             return readFileName
00068         except EnvironmentError, e:
00069             if e.errno != errno.ENOENT:
00070                 raise
00071             return None
            

def locker::_sleep

(

)

[private]

Definition at line 72 of file locker.py.

                : time.sleep(8)

def locker::_tmpFileName

(

fileName )

[private]

Definition at line 49 of file locker.py.

00050                               :
        return "%s.%s.%d" % ( fileName, socket.gethostname(), os.getpid() )

def locker::lock

(

file )

Lock first 10 bytes of a file.

Definition at line 19 of file locker.py.

                  :
        """
        Lock first 10 bytes of a file.
        """ 
        pos = file.tell() # remember current position
        file.seek(0)
        # By default, python tries about 10 times, then throws an exception.
        # We want to wait forever.
        acquired = False
        while not acquired:
            try:
                msvcrt.locking(file.fileno(),msvcrt.LK_LOCK,10)
                acquired = True
            except IOError, x:
                if x.errno != 36: # 36, AKA 'Resource deadlock avoided', is normal
                    raise
        file.seek(pos) # reset position

def locker::unlock

(

file )

Unlock first 10 bytes of a file.

Definition at line 37 of file locker.py.

                    :
        """
        Unlock first 10 bytes of a file.
        """ 
        pos = file.tell() # remember current position
        file.seek(0)
        msvcrt.locking(file.fileno(),msvcrt.LK_UNLCK,10)
        file.seek(pos) # reset position

---

Variable Documentation

locker::LOCK_EX = fcntl.F_WRLCK

Definition at line 12 of file locker.py.

locker::LOCK_NB = fcntl.F_UNLCK

Definition at line 14 of file locker.py.

locker::LOCK_SH = fcntl.F_RDLCK

Definition at line 13 of file locker.py.