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# -*- coding: utf-8 -*-
#
# File: portato/ipc.pyx
# This file is part of the Portato-Project, a graphical portage-frontend.
#
# Copyright (C) 2006-2009 René 'Necoro' Neumann
# This is free software. You may redistribute copies of it under the terms of
# the GNU General Public License version 2.
# There is NO WARRANTY, to the extent permitted by law.
#
# Written by René 'Necoro' Neumann <necoro@necoro.net>
class MessageQueueError(Exception):
"""
Base class for different queue errors.
"""
pass
class MessageQueueRemovedError (MessageQueueError):
"""
This class is used iff the queue is already removed.
"""
pass
cdef class MessageQueue (object):
"""
A simple interface to the SysV message queues.
"""
CREAT = IPC_CREAT
EXCL = IPC_EXCL
cdef int msgid
cdef readonly key_t key
def __init__ (self, key = None, int flags = 0):
"""
Create a new MessageQueue instance. Depending on the passed in flags,
different behavior occurs. See man msgget for the details.
If key is None, a random key is created.
"""
if (flags & IPC_EXCL) and not (flags & IPC_CREAT):
raise ValueError("EXCL must be combined with CREAT.")
if key is None and not (flags & IPC_EXCL):
raise ValueError("The key can only be None if EXCL is set.")
# make sure there is nothing ... obscure
flags &= (IPC_CREAT | IPC_EXCL)
flags |= 0600 # mode
if key is None:
check = True
while check:
self.key = self.random_key()
self.msgid = msgget(self.key, flags)
check = (self.msgid == -1 and errno == EEXIST)
else:
self.key = key
self.msgid = msgget(key, flags)
if self.msgid == -1:
if errno == EACCES:
raise MessageQueueError("Permission denied.")
elif errno == EEXIST:
raise MessageQueueError("Queue already exists.")
elif errno == ENOENT:
raise MessageQueueError("Queue does not exist and CREAT is not set.")
elif errno == ENOMEM or errno == ENOSPC:
raise MemoryError("Insufficient ressources.")
else:
raise OSError(errno, strerror(errno))
def remove (self):
"""
Removes the message queue.
"""
cdef msqid_ds info
cdef int ret
ret = msgctl(self.msgid, IPC_RMID, &info)
if ret == -1:
if errno == EIDRM or errno == EINVAL:
raise MessageQueueRemovedError("Queue already removed.")
elif errno == EPERM:
raise MessageQueueError("Permission denied.")
else:
raise OSError(errno, strerror(errno))
def send (self, message, int type = 1):
"""
Sends a message with a specific type.
The type must be larger zero.
Also note, that this is always blocking.
"""
cdef msg_data * msg
cdef int ret
cdef long size = len(message)
if type <= 0:
raise ValueError("type must be > 0")
if size >= MAX_MESSAGE_SIZE:
raise ValueError("Message must be smaller than %d" % MAX_MESSAGE_SIZE)
msg = <msg_data*>PyMem_Malloc(sizeof(msg_data) + size)
if msg is NULL:
raise MemoryError("Out of memory")
memcpy(msg.mtext, <char*>message, size)
msg.mtype = type
with nogil:
ret = msgsnd(self.msgid, msg, size, 0)
try:
if ret == -1:
if errno == EIDRM or errno == EINVAL:
raise MessageQueueRemovedError("Queue was removed.")
elif errno == EINTR:
raise MessageQueueError("Signaled while waiting.")
elif errno == EACCES:
raise MessageQueueError("Permission denied.")
else:
raise OSError(errno, strerror(errno))
finally:
PyMem_Free(msg)
def receive (self):
"""
Receives a message from the queue and returns the (msg, type) pair.
Note that this method is always blocking.
"""
cdef msg_data * msg
cdef int ret
cdef object retTuple
msg = <msg_data*>PyMem_Malloc(sizeof(msg_data) + MAX_MESSAGE_SIZE)
if msg is NULL:
raise MemoryError("Out of memory")
msg.mtype = 0
with nogil:
ret = msgrcv(self.msgid, msg, <size_t>MAX_MESSAGE_SIZE, 0, 0)
try:
if ret == -1:
if errno == EIDRM or errno == EINVAL:
raise MessageQueueRemovedError("Queue was removed.")
elif errno == EINTR:
raise MessageQueueError("Signaled while waiting.")
elif errno == EACCES:
raise MessageQueueError("Permission denied.")
else:
raise OSError(errno, strerror(errno))
retTuple = (PyString_FromStringAndSize(msg.mtext, ret), msg.mtype)
finally:
PyMem_Free(msg)
return retTuple
cdef inline key_t random_key (self):
return <int>(<double>rand() / (<double>RAND_MAX + 1) * INT_MAX)
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