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- /*
- This file is part of GNUnet.
- Copyright (C) 2012-2013 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 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 Florian Dold
- *
- * @file
- * General-purpose message queue
- *
- * @defgroup mq MQ library
- * General-purpose message queue
- * @{
- */
- #ifndef GNUNET_MQ_H
- #define GNUNET_MQ_H
- /**
- * Allocate an envelope, 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_(((struct GNUNET_MessageHeader**) &(mvar)), (esize) + sizeof *(mvar), (type))
- /**
- * Allocate a GNUNET_MQ_Envelope.
- * The contained 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 allocated envelope
- */
- #define GNUNET_MQ_msg(mvar, type) GNUNET_MQ_msg_extra(mvar, 0, type)
- /**
- * Allocate a GNUNET_MQ_Envelope, 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_Envelope, 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)
- /**
- * Allocate a GNUNET_MQ_Envelope, and append a payload message after the given
- * message struct.
- *
- * @param mvar pointer to a message struct, will be changed to point at the newly allocated message,
- * whose size is 'sizeof(*mvar) + ntohs (mh->size)'
- * @param type message type of the allocated message, has no effect on the nested message
- * @param mh message to nest
- * @return a newly allocated 'struct GNUNET_MQ_Envelope *'
- */
- #define GNUNET_MQ_msg_nested_mh(mvar, type, mh) GNUNET_MQ_msg_nested_mh_((((void)(mvar)->header), (struct GNUNET_MessageHeader**) &(mvar)), sizeof (*(mvar)), (type), mh)
- /**
- * Return a pointer to the message at the end of the given message.
- *
- * @param var pointer to a message struct, the type of the expression determines the base size,
- * the space after the base size is the nested message
- * @return a 'struct GNUNET_MessageHeader *' that points at the nested message of the given message,
- * or NULL if the given message in @a var does not have any space after the message struct
- */
- #define GNUNET_MQ_extract_nested_mh(var) GNUNET_MQ_extract_nested_mh_ ((struct GNUNET_MessageHeader *) (var), sizeof (*(var)))
- /**
- * Implementation of the GNUNET_MQ_extract_nexted_mh macro.
- *
- * @param mh message header to extract nested message header from
- * @param base_size size of the message before the nested message's header appears
- * @return pointer to the nested message, does not copy the message
- */
- const struct GNUNET_MessageHeader *
- GNUNET_MQ_extract_nested_mh_ (const struct GNUNET_MessageHeader *mh,
- uint16_t base_size);
- /**
- * Implementation of the GNUNET_MQ_msg_nested_mh macro.
- *
- * @param mhp pointer to the message header pointer that will be changed to allocate at
- * the newly allocated space for the message.
- * @param base_size size of the data before the nested message
- * @param type type of the message in the envelope
- * @param nested_mh the message to append to the message after base_size
- */
- struct GNUNET_MQ_Envelope *
- GNUNET_MQ_msg_nested_mh_ (struct GNUNET_MessageHeader **mhp,
- uint16_t base_size,
- uint16_t type,
- const struct GNUNET_MessageHeader *nested_mh);
- /**
- * End-marker for the handlers array
- */
- #define GNUNET_MQ_HANDLERS_END {NULL, 0, 0}
- /**
- * Opaque handle to a message queue.
- */
- struct GNUNET_MQ_Handle;
- /**
- * Opaque handle to an envelope.
- */
- struct GNUNET_MQ_Envelope;
- /**
- * Error codes for the queue.
- */
- enum GNUNET_MQ_Error
- {
- /**
- * FIXME: document!
- */
- GNUNET_MQ_ERROR_READ = 1,
- /**
- * FIXME: document!
- */
- GNUNET_MQ_ERROR_WRITE = 2,
- /**
- * FIXME: document!
- */
- 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 functionality of a message queue.
- *
- * @param mq the message queue
- * @param msg the message to send
- * @param impl_state state of the implementation
- */
- typedef void
- (*GNUNET_MQ_SendImpl) (struct GNUNET_MQ_Handle *mq,
- const struct GNUNET_MessageHeader *msg,
- void *impl_state);
- /**
- * Signature of functions implementing the
- * destruction of a message queue.
- * Implementations must not free @a mq, but should
- * take care of @a impl_state.
- *
- * @param mq the message queue to destroy
- * @param impl_state state of the implementation
- */
- typedef void
- (*GNUNET_MQ_DestroyImpl) (struct GNUNET_MQ_Handle *mq,
- void *impl_state);
- /**
- * Implementation function that cancels the currently sent message.
- *
- * @param mq message queue
- * @param impl_state state specific to the implementation
- */
- typedef void
- (*GNUNET_MQ_CancelImpl) (struct GNUNET_MQ_Handle *mq,
- void *impl_state);
- /**
- * Callback used for notifications
- *
- * @param cls closure
- */
- typedef void
- (*GNUNET_MQ_NotifyCallback) (void *cls);
- /**
- * Generic error handler, called with the appropriate
- * error code and the same closure specified at the creation of
- * the message queue.
- * Not every message queue implementation supports an error handler.
- *
- * @param cls closure, same closure as for the message handlers
- * @param error error code
- */
- typedef void
- (*GNUNET_MQ_ErrorHandler) (void *cls,
- enum GNUNET_MQ_Error error);
- /**
- * Message handler for a specific message type.
- */
- struct GNUNET_MQ_MessageHandler
- {
- /**
- * 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 envelope.
- *
- * @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_Envelope *
- GNUNET_MQ_msg_ (struct GNUNET_MessageHeader **mhp,
- uint16_t size,
- uint16_t type);
- /**
- * 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_Envelope *mqm);
- /**
- * Send a message with the give message queue.
- * May only be called once per message.
- *
- * @param mq message queue
- * @param ev the envelope with the message to send.
- */
- void
- GNUNET_MQ_send (struct GNUNET_MQ_Handle *mq,
- struct GNUNET_MQ_Envelope *ev);
- /**
- * 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 ev queued envelope to cancel
- */
- void
- GNUNET_MQ_send_cancel (struct GNUNET_MQ_Envelope *ev);
- /**
- * Associate the assoc_data in mq with a unique request id.
- *
- * @param mq message queue, id will be unique for the queue
- * @param assoc_data to associate
- */
- uint32_t
- GNUNET_MQ_assoc_add (struct GNUNET_MQ_Handle *mq, 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_Handle *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_Handle *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 error_handler error handler
- * @param cls closure for the handlers
- * @return the message queue
- */
- struct GNUNET_MQ_Handle *
- GNUNET_MQ_queue_for_connection_client (struct GNUNET_CLIENT_Connection *connection,
- const struct GNUNET_MQ_MessageHandler *handlers,
- GNUNET_MQ_ErrorHandler error_handler,
- void *cls);
- /**
- * Create a message queue for a GNUNET_SERVER_Client.
- *
- * @param client the client
- * @return the message queue
- */
- struct GNUNET_MQ_Handle *
- 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 cancel function that implements canceling a message
- * @param impl_state for the queue, passed to @a send, @a destroy and @a cancel
- * @param handlers array of message handlers
- * @param error_handler handler for read and write errors
- * @param cls closure for message handlers and error handler
- * @return a new message queue
- */
- struct GNUNET_MQ_Handle *
- GNUNET_MQ_queue_for_callbacks (GNUNET_MQ_SendImpl send,
- GNUNET_MQ_DestroyImpl destroy,
- GNUNET_MQ_CancelImpl cancel,
- void *impl_state,
- const struct GNUNET_MQ_MessageHandler *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.
- *
- * If the message queue does not support receiving messages,
- * this function has no effect.
- *
- * @param mq message queue
- * @param new_handlers new handlers
- * @param cls new closure for the handlers
- */
- void
- GNUNET_MQ_replace_handlers (struct GNUNET_MQ_Handle *mq,
- const struct GNUNET_MQ_MessageHandler *new_handlers,
- void *cls);
- /**
- * Call a callback once the envelope has been sent, that is,
- * sending it can not be canceled anymore.
- * There can be only one notify sent callback per envelope.
- *
- * @param ev 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_Envelope *ev,
- GNUNET_MQ_NotifyCallback cb,
- void *cls);
- /**
- * Destroy the message queue.
- *
- * @param mq message queue to destroy
- */
- void
- GNUNET_MQ_destroy (struct GNUNET_MQ_Handle *mq);
- /**
- * 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 (struct GNUNET_MQ_Handle *mq,
- const struct GNUNET_MessageHeader *mh);
- /**
- * Call the error handler of a message queue with the given
- * error code. If there is no error handler, log a warning.
- *
- * This function is intended to be used for the implementation
- * of message queues.
- *
- * @param mq message queue
- * @param error the error type
- */
- void
- GNUNET_MQ_inject_error (struct GNUNET_MQ_Handle *mq,
- enum GNUNET_MQ_Error error);
- /**
- * Call the send implementation for the next queued message,
- * if any.
- * Only useful for implementing message queues,
- * results in undefined behavior if not used carefully.
- *
- * @param mq message queue to send the next message with
- */
- void
- GNUNET_MQ_impl_send_continue (struct GNUNET_MQ_Handle *mq);
- /**
- * Get the message that should currently be sent.
- * The returned message is only valid until #GNUNET_MQ_impl_send_continue
- * is called.
- * Fails if there is no current message.
- * Only useful for implementing message queues,
- * results in undefined behavior if not used carefully.
- *
- * @param mq message queue with the current message, only valid
- * until #GNUNET_MQ_impl_send_continue is called
- * @return message to send, never NULL
- */
- const struct GNUNET_MessageHeader *
- GNUNET_MQ_impl_current (struct GNUNET_MQ_Handle *mq);
- /**
- * Get the implementation state associated with the
- * message queue.
- *
- * While the GNUNET_MQ_Impl* callbacks receive the
- * implementation state, continuations that are scheduled
- * by the implementation function often only have one closure
- * argument, with this function it is possible to get at the
- * implementation state when only passing the GNUNET_MQ_Handle
- * as closure.
- *
- * @param mq message queue with the current message
- * @return message to send, never NULL
- */
- void *
- GNUNET_MQ_impl_state (struct GNUNET_MQ_Handle *mq);
- #endif
- /** @} */ /* end of group mq */
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