path: root/src/util/mq.c

/*
     This file is part of GNUnet.
     Copyright (C) 2012-2017 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     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
     Affero General Public License for more details.
    
     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @author Florian Dold
 * @file util/mq.c
 * @brief general purpose request queue
 */
#include "platform.h"
#include "gnunet_util_lib.h"

#define LOG(kind,...) GNUNET_log_from (kind, "util-mq",__VA_ARGS__)


struct GNUNET_MQ_Envelope
{
  /**
   * Messages are stored in a linked list.
   * Each queue has its own list of envelopes.
   */
  struct GNUNET_MQ_Envelope *next;

  /**
   * Messages are stored in a linked list
   * Each queue has its own list of envelopes.
   */
  struct GNUNET_MQ_Envelope *prev;

  /**
   * Actual allocated message header.
   * The GNUNET_MQ_Envelope header is allocated at
   * the end of the message.
   */
  struct GNUNET_MessageHeader *mh;

  /**
   * Queue the message is queued in, NULL if message is not queued.
   */
  struct GNUNET_MQ_Handle *parent_queue;

  /**
   * Called after the message was sent irrevocably.
   */
  GNUNET_SCHEDULER_TaskCallback sent_cb;

  /**
   * Closure for @e send_cb
   */
  void *sent_cls;

  /**
   * Flags that were set for this envelope by
   * #GNUNET_MQ_env_set_options().   Only valid if
   * @e have_custom_options is set.
   */
  uint64_t flags;

  /**
   * Additional options buffer set for this envelope by
   * #GNUNET_MQ_env_set_options().  Only valid if
   * @e have_custom_options is set.
   */
  const void *extra;

  /**
   * Did the application call #GNUNET_MQ_env_set_options()?
   */
  int have_custom_options;
};


/**
 * Handle to a message queue.
 */
struct GNUNET_MQ_Handle
{
  /**
   * Handlers array, or NULL if the queue should not receive messages
   */
  struct GNUNET_MQ_MessageHandler *handlers;

  /**
   * Actual implementation of message sending,
   * called when a message is added
   */
  GNUNET_MQ_SendImpl send_impl;

  /**
   * Implementation-dependent queue destruction function
   */
  GNUNET_MQ_DestroyImpl destroy_impl;

  /**
   * Implementation-dependent send cancel function
   */
  GNUNET_MQ_CancelImpl cancel_impl;

  /**
   * Implementation-specific state
   */
  void *impl_state;

  /**
   * Callback will be called when an error occurs.
   */
  GNUNET_MQ_ErrorHandler error_handler;

  /**
   * Closure for the error handler.
   */
  void *error_handler_cls;

  /**
   * Task to asynchronously run #impl_send_continue().
   */
  struct GNUNET_SCHEDULER_Task *send_task;

  /**
   * Linked list of messages pending to be sent
   */
  struct GNUNET_MQ_Envelope *envelope_head;

  /**
   * Linked list of messages pending to be sent
   */
  struct GNUNET_MQ_Envelope *envelope_tail;

  /**
   * Message that is currently scheduled to be
   * sent. Not the head of the message queue, as the implementation
   * needs to know if sending has been already scheduled or not.
   */
  struct GNUNET_MQ_Envelope *current_envelope;

  /**
   * Map of associations, lazily allocated
   */
  struct GNUNET_CONTAINER_MultiHashMap32 *assoc_map;

  /**
   * Functions to call on queue destruction; kept in a DLL.
   */
  struct GNUNET_MQ_DestroyNotificationHandle *dnh_head;

  /**
   * Functions to call on queue destruction; kept in a DLL.
   */
  struct GNUNET_MQ_DestroyNotificationHandle *dnh_tail;

  /**
   * Additional options buffer set for this queue by
   * #GNUNET_MQ_set_options().  Default is 0.
   */
  const void *default_extra;

  /**
   * Flags that were set for this queue by
   * #GNUNET_MQ_set_options().   Default is 0.
   */
  uint64_t default_flags;

  /**
   * Next id that should be used for the @e assoc_map,
   * initialized lazily to a random value together with
   * @e assoc_map
   */
  uint32_t assoc_id;

  /**
   * Number of entries we have in the envelope-DLL.
   */
  unsigned int queue_length;

  /**
   * #GNUNET_YES if GNUNET_MQ_impl_evacuate was called.
   * FIXME: is this dead?
   */
  int evacuate_called;

  /**
   * #GNUNET_YES if GNUNET_MQ_impl_send_in_flight() was called.
   */
  int in_flight;
};


/**
 * Call the message message handler that was registered
 * for the type of the given message in the given message queue.
 *
 * This function is indended to be used for the implementation
 * of message queues.
 *
 * @param mq message queue with the handlers
 * @param mh message to dispatch
 */
void
GNUNET_MQ_inject_message (<