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from stdlib cimport *
cdef extern from "errno.h":
int errno
cdef enum:
EACCES, EEXIST, ENOENT, ENOMEM, ENOSPC,
EINVAL, EPERM, EIDRM, EINTR
cdef extern from *:
int INT_MAX
int RAND_MAX
ctypedef size_t int
int rand()
cdef extern from "string.h":
char* strerror(int errno)
void* memcpy (void* dst, void* src, size_t len)
cdef extern from "sys/msg.h" nogil:
cdef enum:
IPC_CREAT, IPC_EXCL, IPC_NOWAIT,
IPC_RMID
ctypedef int key_t
struct msqid_ds:
pass
int msgget(key_t key, int msgflg)
int msgctl(int msqid, int cmd, msqid_ds* buf)
int msgsnd(int msgid, void* msgp, size_t msgsz, int msgflg)
int msgrcv(int msgid, void* msgp, size_t msgsz, long msgtype, int msgflg)
cdef struct msg_data:
long mtype
char mtext[1]
cdef enum:
MAX_MESSAGE_SIZE = 2048
class MessageQueueError(Exception):
pass
class MessageQueueRemovedError (MessageQueueError):
pass
cdef class MessageQueue (object):
CREAT = IPC_CREAT
EXCL = IPC_EXCL
cdef int msgid
cdef readonly key_t key
def __init__ (self, key = None, int flags = 0):
if (flags & IPC_EXCL) and not (flags & IPC_CREAT):
raise MessageQueueError("EXCL must be combined with CREAT.")
if key is None and not (flags & IPC_EXCL):
raise MessageQueueError("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 MessageQueueError("Insufficient ressources.")
else:
raise OSError(errno, strerror(errno))
def remove (self):
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):
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*>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:
free(msg)
def receive (self):
cdef msg_data * msg
cdef int ret
cdef object retTuple
msg = <msg_data*>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 = (msg.mtext, msg.mtype)
finally:
free(msg)
return retTuple
cdef key_t random_key (self):
return <int>(<double>rand() / (<double>RAND_MAX + 1) * INT_MAX)
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