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# -*- python -*-
'''
cmdipc — System V and POSIX IPC from the command line
Copyright © 2014 Mattias Andrée (m@maandree.se)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
'''
import os
import posix_ipc # http://semanchuk.com/philip/posix_ipc
SignalError = posix_ipc.SignalError
PermissionsError = posix_ipc.PermissionsError
ExistentialError = posix_ipc.ExistentialError
BusyError = posix_ipc.BusyError
CREAT = posix_ipc.O_CREAT
EXCL = posix_ipc.O_EXCL
def keycat(*keys):
return ''.join(keys)
def keysep(keys):
return ['/' + key for key in keys[1:].split('/')]
class Semaphore(posix_ipc.Semaphore):
def __init__(self, *args, **kwargs):
posix_ipc.Semaphore.__init__(self, *args, **kwargs)
self.key = self.name
def acquire(self, timeout = None, delta = 1):
have = 0
try:
for _ in range(abs(delta)):
posix_ipc.Semaphore.acquire(self, timeout)
have += 1
except Exception as e:
try:
self.release(have)
except:
pass
raise e
def release(self, delta = 1):
for _ in range(abs(delta)):
posix_ipc.Semaphore.release(self)
def P(self, timeout = None, delta = 1):
self.acquire(timeout, delta)
def V(self, delta = 1):
self.release(delta)
def Z(self, timeout = None):
if not timeout == 0:
import sys
print('Z operation over POSIX semaphore require spinlock', file = sys.stderr)
if timeout is None:
while not self.value == 0:
pass
elif timeout == 0:
if not self.value == 0:
raise BusyError()
else:
import time
end = time.monotonic() + timeout
while not self.value == 0:
if time.monotonic() > end:
raise BusyError()
def set_value(self, value):
n = abs(value) - self.value
try:
if n > 0:
for _ in range(n):
self.V()
elif n < 0:
for _ in range(-n):
self.P(0)
except BusyError:
pass
def remove(self):
self.unlink()
self.close()
class SharedMemory(posix_ipc.SharedMemory):
def __init__(self, *args, **kwargs):
posix_ipc.SharedMemory.__init__(self, *args, **kwargs)
self.key = self.name
def read(self, byte_count = 0, offset = 0):
rc = []
byte_count = self.size if byte_count == 0 else byte_count
byte_count = min(byte_count, self.size - offset)
os.lseek(self.fd, offset, os.SEEK_SET)
while len(rc) < byte_count:
rc += list(os.read(self.fd, byte_count - len(rc)))
return bytes(rc)
def write(self, s, offset = 0):
s = s[:min(len(s), self.size - offset)]
os.lseek(self.fd, offset, os.SEEK_SET)
while len(s) > 0:
s = s[os.write(self.fd, s):]
def close(self):
self.close_fd()
def remove(self):
self.unlink()
self.close()
class MessageQueue(posix_ipc.MessageQueue):
def __init__(self, *args, **kwargs):
posix_ipc.MessageQueue.__init__(self, *args, **kwargs)
self.key = self.name
def remove(self):
self.unlink()
self.close()
|
