1 files changed, 478 insertions, 0 deletions

diff --git a/src/include/gnunet_mq_lib.h b/src/include/gnunet_mq_lib.h
new file mode 100644
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--- /dev/null
+++ b/src/include/gnunet_mq_lib.h
@@ -0,0 +1,478 @@
+/*
+     This file is part of GNUnet.
+     (C) 2012 Christian Grothoff (and other contributing authors)
+
+     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 2, 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., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @author Florian Dold
+ * @file set/mq.h
+ * @brief general purpose request queue
+ */
+#ifndef GNUNET_MQ_H
+#define GNUNET_MQ_H
+
+#include "gnunet_common.h"
+
+
+/**
+ * Allocate a GNUNET_MQ_Message, with extra space allocated after the space needed
+ * by the message struct.
+ * The allocated message will already have the type and size field set.
+ *
+ * @param mvar variable to store the allocated message in;
+ *             must have a header field
+ * @param esize extra space to allocate after the message
+ * @param type type of the message
+ * @return the MQ message
+ */
+#define GNUNET_MQ_msg_extra(mvar, esize, type) GNUNET_MQ_msg_((((void)(mvar)->header), (struct GNUNET_MessageHeader**) &(mvar)), (esize) + sizeof *(mvar), (type))
+
+/**
+ * Allocate a GNUNET_MQ_Message.
+ * The allocated message will already have the type and size field set.
+ *
+ * @param mvar variable to store the allocated message in;
+ *             must have a header field
+ * @param type type of the message
+ * @return the MQ message
+ */
+#define GNUNET_MQ_msg(mvar, type) GNUNET_MQ_msg_extra(mvar, 0, type)
+
+/**
+ * Append data to the end of an existing MQ message.
+ * If the operation is successful, mqm is changed to point to the new MQ message,
+ * and GNUNET_OK is returned.
+ * On failure, GNUNET_SYSERR is returned, and the pointer mqm is not changed,
+ * the user of this API must take care of disposing the already allocated message
+ * (either by sending it, or by using GNUNET_MQ_discard)
+ *
+ * @param mqm MQ message to augment with additional data
+ * @param src source buffer for the additional data
+ * @param len length of the additional data
+ * @return GNUNET_SYSERR if nesting the message failed,
+ *         GNUNET_OK on success
+ */
+#define GNUNET_MQ_nest(mqm, src, len) GNUNET_MQ_nest_ (&mqm, src, len)
+
+
+/**
+ * Append a message to the end of an existing MQ message.
+ * If the operation is successful, mqm is changed to point to the new MQ message,
+ * and GNUNET_OK is returned.
+ * On failure, GNUNET_SYSERR is returned, and the pointer mqm is not changed,
+ * the user of this API must take care of disposing the already allocated message
+ * (either by sending it, or by using GNUNET_MQ_discard)
+ *
+ * @param mqm MQ message to augment with additional data
+ * @param mh the message to append, must be of type 'struct GNUNET_MessageHeader *'
+ */
+#define GNUNET_MQ_nest_mh(mqm, mh) ((NULL == mh) ? (GNUNET_OK) : GNUNET_MQ_nest((mqm), (mh), ntohs ((mh)->size)))
+
+
+/**
+ * Allocate a GNUNET_MQ_Message, where the message only consists of a header.
+ * The allocated message will already have the type and size field set.
+ *
+ * @param type type of the message
+ */
+#define GNUNET_MQ_msg_header(type) GNUNET_MQ_msg_ (NULL, sizeof (struct GNUNET_MessageHeader), type)
+
+
+/**
+ * Allocate a GNUNET_MQ_Message, where the message only consists of a header and extra space.
+ * The allocated message will already have the type and size field set.
+ *
+ * @param mh pointer that will changed to point at to the allocated message header
+ * @param esize extra space to allocate after the message header
+ * @param type type of the message
+ */
+#define GNUNET_MQ_msg_header_extra(mh, esize, type) GNUNET_MQ_msg_ (&mh, (esize) + sizeof (struct GNUNET_MessageHeader), type)
+
+
+/**
+ * End-marker for the handlers array
+ */
+#define GNUNET_MQ_HANDLERS_END {NULL, 0, 0}
+
+
+struct GNUNET_MQ_MessageQueue;
+
+struct GNUNET_MQ_Message;
+
+enum GNUNET_MQ_Error
+{
+  GNUNET_MQ_ERROR_READ = 1,
+  GNUNET_MQ_ERROR_WRITE = 2,
+  GNUNET_MQ_ERROR_TIMEOUT = 4
+};
+
+
+/**
+ * Called when a message has been received.
+ *
+ * @param cls closure
+ * @param msg the received message
+ */
+typedef void (*GNUNET_MQ_MessageCallback) (void *cls, const struct GNUNET_MessageHeader *msg);
+
+
+/**
+ * Signature of functions implementing the
+ * sending part of a message queue
+ *
+ * @param q the message queue
+ * @param m the message
+ */
+typedef void
+(*GNUNET_MQ_SendImpl) (struct GNUNET_MQ_MessageQueue *q, struct GNUNET_MQ_Message *m);
+
+
+typedef void
+(*GNUNET_MQ_DestroyImpl) (struct GNUNET_MQ_MessageQueue *q);
+
+
+/**
+ * Callback used for notifications
+ *
+ * @param cls closure
+ */
+typedef void (*GNUNET_MQ_NotifyCallback) (void *cls);
+
+
+typedef void (*GNUNET_MQ_ErrorHandler) (void *cls, enum GNUNET_MQ_Error error);
+
+
+struct GNUNET_MQ_Message
+{
+  /**
+   * Messages are stored in a linked list
+   */
+  struct GNUNET_MQ_Message *next;
+
+  /**
+   * Messages are stored in a linked list
+   */
+  struct GNUNET_MQ_Message *prev;
+
+  /**
+   * Actual allocated message header,
+   * usually points to the end of the containing GNUNET_MQ_Message
+   */
+  struct GNUNET_MessageHeader *mh;
+
+  /**
+   * Queue the message is queued in, NULL if message is not queued.
+   */
+  struct GNUNET_MQ_MessageQueue *parent_queue;
+
+  /**
+   * Called after the message was sent irrevokably
+   */
+  GNUNET_MQ_NotifyCallback sent_cb;
+
+  /**
+   * Closure for send_cb
+   */
+  void *sent_cls;
+};
+
+
+/**
+ * Handle to a message queue.
+ */
+struct GNUNET_MQ_MessageQueue
+{
+  /**
+   * Handlers array, or NULL if the queue should not receive messages
+   */
+  const struct GNUNET_MQ_Handler *handlers;
+
+  /**
+   * Closure for the handler callbacks,
+   * as well as for the error handler.
+   */
+  void *handlers_cls;
+
+  /**
+   * 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-specific state
+   */
+  void *impl_state;
+
+  /**
+   * Callback will be called when an error occurs.
+   */
+  GNUNET_MQ_ErrorHandler error_handler;
+
+  /**
+   * Linked list of messages pending to be sent
+   */
+  struct GNUNET_MQ_Message *msg_head;
+
+  /**
+   * Linked list of messages pending to be sent
+   */
+  struct GNUNET_MQ_Message *msg_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_Message *current_msg;
+
+  /**
+   * Map of associations, lazily allocated
+   */
+  struct GNUNET_CONTAINER_MultiHashMap32 *assoc_map;
+
+  /**
+   * Next id that should be used for the assoc_map,
+   * initialized lazily to a random value together with
+   * assoc_map
+   */
+  uint32_t assoc_id;
+};
+
+
+/**
+ * Message handler for a specific message type.
+ */
+struct GNUNET_MQ_Handler
+{
+  /**
+   * Callback, called every time a new message of 
+   * the specified type has been receied.
+   */
+  GNUNET_MQ_MessageCallback cb;
+
+
+  /**
+   * Type of the message this handler covers.
+   */
+  uint16_t type;
+
+  /**
+   * Expected size of messages of this type.  Use 0 for
+   * variable-size.  If non-zero, messages of the given
+   * type will be discarded (and the connection closed)
+   * if they do not have the right size.
+   */
+  uint16_t expected_size;
+};
+
+
+/**
+ * Create a new message for MQ.
+ * 
+ * @param mhp message header to store the allocated message header in, can be NULL
+ * @param size size of the message to allocate
+ * @param type type of the message, will be set in the allocated message
+ * @return the allocated MQ message
+ */
+struct GNUNET_MQ_Message *
+GNUNET_MQ_msg_ (struct GNUNET_MessageHeader **mhp, uint16_t size, uint16_t type);
+
+
+/**
+ * Resize the the mq message pointed to by mqmp,
+ * and append the given data to it.
+ *
+ * @param mqmp pointer to a mq message pointer
+ * @param src source of the data to append
+ * @param len length of the data to append
+ * @return GNUNET_OK on success,
+ *         GNUNET_SYSERR on error (e.g. if len is too large)
+ */
+int
+GNUNET_MQ_nest_ (struct GNUNET_MQ_Message **mqmp,
+                 const void *src, uint16_t len);
+
+
+/**
+ * Discard the message queue message, free all
+ * allocated resources. Must be called in the event
+ * that a message is created but should not actually be sent.
+ *
+ * @param mqm the message to discard
+ */
+void
+GNUNET_MQ_discard (struct GNUNET_MQ_Message *mqm);
+
+
+/**
+ * Send a message with the give message queue.
+ * May only be called once per message.
+ * 
+ * @param mq message queue
+ * @param mqm the message to send.
+ */
+void
+GNUNET_MQ_send (struct GNUNET_MQ_MessageQueue *mq, struct GNUNET_MQ_Message *mqm);
+
+
+/**
+ * Cancel sending the message. Message must have been sent with GNUNET_MQ_send before.
+ * May not be called after the notify sent callback has been called
+ *
+ * @param mqm queued message to cancel
+ */
+void
+GNUNET_MQ_send_cancel (struct GNUNET_MQ_Message *mqm);
+
+
+/**
+ * Associate the assoc_data in mq with a unique request id.
+ *
+ * @param mq message queue, id will be unique for the queue
+ * @param mqm message to associate
+ * @param assoc_data to associate
+ */
+uint32_t
+GNUNET_MQ_assoc_add (struct GNUNET_MQ_MessageQueue *mq,
+                     struct GNUNET_MQ_Message *mqm,
+                     void *assoc_data);
+
+/**
+ * Get the data associated with a request id in a queue
+ *
+ * @param mq the message queue with the association
+ * @param request_id the request id we are interested in
+ * @return the associated data
+ */
+void *
+GNUNET_MQ_assoc_get (struct GNUNET_MQ_MessageQueue *mq, uint32_t request_id);
+
+
+/**
+ * Remove the association for a request id
+ *
+ * @param mq the message queue with the association
+ * @param request_id the request id we want to remove
+ * @return the associated data
+ */
+void *
+GNUNET_MQ_assoc_remove (struct GNUNET_MQ_MessageQueue *mq, uint32_t request_id);
+
+
+
+/**
+ * Create a message queue for a GNUNET_CLIENT_Connection.
+ * If handlers are specfied, receive messages from the connection.
+ *
+ * @param connection the client connection
+ * @param handlers handlers for receiving messages
+ * @param cls closure for the handlers
+ * @return the message queue
+ */
+struct GNUNET_MQ_MessageQueue *
+GNUNET_MQ_queue_for_connection_client (struct GNUNET_CLIENT_Connection *connection,
+                                       const struct GNUNET_MQ_Handler *handlers,
+                                       void *cls);
+
+
+/**
+ * Create a message queue for a GNUNET_STREAM_Socket.
+ *
+ * @param client the client
+ * @return the message queue
+ */
+struct GNUNET_MQ_MessageQueue *
+GNUNET_MQ_queue_for_server_client (struct GNUNET_SERVER_Client *client);
+
+
+/**
+ * Create a message queue for the specified handlers.
+ *
+ * @param send function the implements sending messages
+ * @param destroy function that implements destroying the queue
+ * @param state for the queue, passed to 'send' and 'destroy'
+ * @param handlers array of message handlers
+ * @param error_handler handler for read and write errors
+ * @return a new message queue
+ */
+struct GNUNET_MQ_MessageQueue *
+GNUNET_MQ_queue_for_callbacks (GNUNET_MQ_SendImpl send,
+                               GNUNET_MQ_DestroyImpl destroy,
+                               void *impl_state,
+                               struct GNUNET_MQ_Handler *handlers,
+                               GNUNET_MQ_ErrorHandler error_handler,
+                               void *cls);
+                               
+
+
+/**
+ * Replace the handlers of a message queue with new handlers.
+ * Takes effect immediately, even for messages that already have been received, but for
+ * with the handler has not been called.
+ *
+ * @param mq message queue
+ * @param new_handlers new handlers
+ * @param cls new closure for the handlers
+ */
+void
+GNUNET_MQ_replace_handlers (struct GNUNET_MQ_MessageQueue *mq,
+                            const struct GNUNET_MQ_Handler *new_handlers,
+                            void *cls);
+
+
+/**
+ * Call a callback once the message has been sent, that is, the message
+ * can not be canceled anymore.
+ * There can be only one notify sent callback per message.
+ *
+ * @param mqm message to call the notify callback for
+ * @param cb the notify callback
+ * @param cls closure for the callback
+ */
+void
+GNUNET_MQ_notify_sent (struct GNUNET_MQ_Message *mqm,
+                       GNUNET_MQ_NotifyCallback cb,
+                       void *cls);
+
+
+/**
+ * Destroy the message queue.
+ *
+ * @param mq message queue to destroy
+ */
+void
+GNUNET_MQ_destroy (struct GNUNET_MQ_MessageQueue *mq);
+
+
+/**
+ * Call the right callback for a message.
+ *
+ * @param mq message queue with the handlers
+ * @param mh message to dispatch
+ */
+void
+GNUNET_MQ_dispatch (struct GNUNET_MQ_MessageQueue *mq,
+                    const struct GNUNET_MessageHeader *mh);
+
+#endif