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-rw-r--r--portato/ipc.pyx35
1 files changed, 32 insertions, 3 deletions
diff --git a/portato/ipc.pyx b/portato/ipc.pyx
index 4a06102..e9340cf 100644
--- a/portato/ipc.pyx
+++ b/portato/ipc.pyx
@@ -11,12 +11,21 @@
# 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
@@ -25,12 +34,18 @@ cdef class MessageQueue (object):
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 MessageQueueError("EXCL must be combined with CREAT.")
+ raise ValueError("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.")
+ raise ValueError("The key can only be None if EXCL is set.")
# make sure there is nothing ... obscure
flags &= (IPC_CREAT | IPC_EXCL)
@@ -55,11 +70,14 @@ cdef class MessageQueue (object):
elif errno == ENOENT:
raise MessageQueueError("Queue does not exist and CREAT is not set.")
elif errno == ENOMEM or errno == ENOSPC:
- raise MessageQueueError("Insufficient ressources.")
+ raise MemoryError("Insufficient ressources.")
else:
raise OSError(errno, strerror(errno))
def remove (self):
+ """
+ Removes the message queue.
+ """
cdef msqid_ds info
cdef int ret
@@ -74,6 +92,12 @@ cdef class MessageQueue (object):
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)
@@ -109,6 +133,11 @@ cdef class MessageQueue (object):
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