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/*
This file is part of GNUnet.
Copyright (C) 2012-2016 GNUnet e.V.
GNUnet 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, or (at your
option) any later version.
GNUnet 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 GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
/**
* @author Christian Grothoff
*
* @file
* General-purpose broadcast mechanism for message queues
*
* @defgroup mq NC library
* General-purpose broadcast mechanism for message queues
*
* @see [Documentation](https://gnunet.org/nc)
*
* @{
*/
#ifndef GNUNET_NC_H
#define GNUNET_NC_H
/**
* The notification context is the key datastructure for a convenience
* API used for transmission of notifications to the subscriber until the
* subscriber disconnects (or the notification context is destroyed, in
* which case we disconnect these subscribers). Essentially, all
* (notification) messages are queued up until the subscriber is able to
* read them.
*/
struct GNUNET_NotificationContext;
/**
* Create a new notification context.
*
* @param queue_length maximum number of messages to keep in
* the notification queue; optional messages are dropped
* if the queue gets longer than this number of messages
* @return handle to the notification context
*/
struct GNUNET_NotificationContext *
GNUNET_notification_context_create (unsigned int queue_length);
/**
* Destroy the context, force disconnect for all subscribers.
*
* @param nc context to destroy.
*/
void
GNUNET_notification_context_destroy (struct GNUNET_NotificationContext *nc);
/**
* Add a subscriber to the notification context.
*
* @param nc context to modify
* @param mq message queue add
*/
void
GNUNET_notification_context_add (struct GNUNET_NotificationContext *nc,
struct GNUNET_MQ_Handle *mq);
/**
* Send a message to all subscribers of this context.
*
* @param nc context to modify
* @param msg message to send
* @param can_drop can this message be dropped due to queue length limitations
*/
void
GNUNET_notification_context_broadcast (struct GNUNET_NotificationContext *nc,
const struct GNUNET_MessageHeader *msg,
int can_drop);
/**
* Return active number of subscribers in this context.
*
* @param nc context to query
* @return number of current subscribers
*/
unsigned int
GNUNET_notification_context_get_size (struct GNUNET_NotificationContext *nc);
#endif
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