/*
This file is part of GNUnet.
- Copyright (C) 2012-2013 Christian Grothoff (and other contributing authors)
+ 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
/**
* @author Florian Dold
- * @file include/gnunet_mq_lib.h
- * @brief general purpose message queue
- * @defgroup mq general purpose message queue
+ * @author Christian Grothoff
+ *
+ * @file
+ * General-purpose message queue
+ *
+ * @defgroup mq MQ library
+ * General-purpose message queue
+ *
+ * @see [Documentation](https://gnunet.org/message-queue-api)
+ *
* @{
*/
#ifndef GNUNET_MQ_H
/**
- * Implementation of the GNUNET_MQ_msg_nested_mh macro.
+ * Opaque handle to an envelope.
+ */
+struct GNUNET_MQ_Envelope;
+
+
+/**
+ * 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.
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!
+ * Failed to read message from the network.
+ * FIXME: Likely not properly distinguished
+ * from TIMEOUT case in the code!
*/
GNUNET_MQ_ERROR_READ = 1,
/**
* FIXME: document!
*/
- GNUNET_MQ_ERROR_TIMEOUT = 4
+ GNUNET_MQ_ERROR_TIMEOUT = 4,
+
+ /**
+ * We received a message that was malformed and thus
+ * could not be passed to its handler.
+ */
+ GNUNET_MQ_ERROR_MALFORMED = 8
};
const struct GNUNET_MessageHeader *msg);
+/**
+ * Called when a message needs to be validated.
+ *
+ * @param cls closure
+ * @param msg the received message
+ * @return #GNUNET_OK if the message is well-formed,
+ * #GNUNET_SYSERR if not
+ */
+typedef int
+(*GNUNET_MQ_MessageValidationCallback) (void *cls,
+ const struct GNUNET_MessageHeader *msg);
+
+
/**
* Signature of functions implementing the
* sending functionality of a message queue.
* the message queue.
* Not every message queue implementation supports an error handler.
*
- * @param cls closure, same closure as for the message handlers
+ * @param cls closure
* @param error error code
*/
typedef void
*/
struct GNUNET_MQ_MessageHandler
{
+ /**
+ * Callback to validate a message of the specified @e type.
+ * The closure given to @e mv will be this struct (not @e ctx).
+ * Using NULL means only size-validation using
+ * @e expected_size. In this case, @e expected_size must
+ * be non-zero.
+ */
+ GNUNET_MQ_MessageValidationCallback mv;
+
/**
* Callback, called every time a new message of
- * the specified type has been receied.
+ * the specified @e type has been receied.
+ * The closure given to @e mv will be this struct (not @e ctx).
*/
GNUNET_MQ_MessageCallback cb;
/**
- * Type of the message this handler covers.
+ * Closure for @e mv and @e cb.
+ */
+ void *cls;
+
+ /**
+ * Type of the message this handler covers, in host byte order.
*/
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.
+ * Expected size of messages of this type. Minimum size of the
+ * message if @e mv is non-NULL. Messages of the given type will be
+ * discarded (and the connection closed with an error reported to
+ * the application) if they do not have the right size.
*/
uint16_t expected_size;
};
+/**
+ * End-marker for the handlers array
+ */
+#define GNUNET_MQ_handler_end() {NULL, NULL, NULL, 0, 0}
+
+
+/**
+ * Defines a static function @a name which takes as a single argument
+ * a message handler for fixed-sized messages of type @a code and with
+ * a message type argument of @a str. Given such an argument, the
+ * function @name will return a `struct GNUNET_MQ_MessageHandler`
+ * for the given message type.
+ *
+ * The macro is to be used as follows:
+ * <code>
+ * struct GNUNET_MessageTest { ... }; // must be fixed size
+ * static void
+ * handle_test_message (void *cls,
+ * const struct GNUNET_MessageTest *msg)
+ * { ... }
+ *
+ * GNUNET_MQ_hd_fixed_size(test_message,
+ * GNUNET_MESSAGE_TYPE_TEST,
+ * struct GNUNET_MessageTest);
+ * struct GNUNET_MQ_MessageHandler handlers[] = {
+ * make_test_message_handler (),
+ * GNUNET_MQ_handler_end()
+ * };
+ *
+ * @param name unique basename for the functions
+ * @param code message type constant
+ * @param str type of the message (a struct)
+ */
+#define GNUNET_MQ_hd_fixed_size(name,code,str) \
+ struct GNUNET_MQ_MessageHandler \
+ make_##name##_handler (void *cls) { \
+ void (*cb)(void *cls, const str *msg) = &handle_##name; \
+ struct GNUNET_MQ_MessageHandler mh = { \
+ NULL, (GNUNET_MQ_MessageCallback) cb, \
+ cls, code, sizeof (str) }; \
+ return mh; \
+ }
+
+
+/**
+ * Defines a static function @a name which takes two arguments and a
+ * context-pointer for validating and handling variable-sized messages
+ * of type @a code and with a message type argument of @a str. Given
+ * such arguments, the function @name will return a `struct
+ * GNUNET_MQ_MessageHandler` for the given message type.
+ *
+ * The macro is to be used as follows:
+ * <code>
+ * struct GNUNET_MessageTest { ... }; // can be variable size
+ * GNUNET_MQ_hd_var_size(test_message,
+ * GNUNET_MESSAGE_TYPE_TEST,
+ * struct GNUNET_MessageTest);
+ * static int
+ * check_test (void *cls,
+ * const struct GNUNET_MessageTest *msg)
+ * {
+ * const char *ctx = cls;
+ * GNUNET_assert (0 == strcmp ("context", ctx));
+ * // ...
+ * }
+ * static void
+ * handle_test (void *cls,
+ * const struct GNUNET_MessageTest *msg)
+ * {
+ * const char *ctx = cls;
+ * GNUNET_assert (0 == strcmp ("context", ctx));
+ * // ...
+ * }
+ *
+ * struct GNUNET_MQ_MessageHandler handlers[] = {
+ * make_test_message_handler ("context"),
+ * GNUNET_MQ_handler_end()
+ * };
+ *
+ * @param name unique basename for the functions
+ * @param code message type constant
+ * @param str type of the message (a struct)
+ */
+#define GNUNET_MQ_hd_var_size(name,code,str) \
+ struct GNUNET_MQ_MessageHandler \
+ make_##name##_handler (void *ctx) { \
+ int (*mv)(void *cls, const str *msg) = &check_##name; \
+ void (*cb)(void *cls, const str *msg) = &handle_##name;\
+ struct GNUNET_MQ_MessageHandler mh = \
+ { (GNUNET_MQ_MessageValidationCallback) mv, \
+ (GNUNET_MQ_MessageCallback) cb, \
+ ctx, code, sizeof (str) }; \
+ return mh; \
+ }
+
/**
* Create a new envelope.
uint16_t type);
+/**
+ * Create a new envelope by copying an existing message.
+ *
+ * @param hdr header of the message to copy
+ * @return envelope containing @a hdr
+ */
+struct GNUNET_MQ_Envelope *
+GNUNET_MQ_msg_copy (const struct GNUNET_MessageHeader *hdr);
+
+
/**
* Discard the message queue message, free all
* allocated resources. Must be called in the event
/**
- * Send a message with the give message queue.
+ * Obtain the current length of the message queue.
+ *
+ * @param mq queue to inspect
+ * @return number of queued, non-transmitted messages
+ */
+unsigned int
+GNUNET_MQ_get_length (struct GNUNET_MQ_Handle *mq);
+
+
+/**
+ * Send a message with the given message queue.
* May only be called once per message.
*
* @param mq message queue
struct GNUNET_MQ_Envelope *ev);
+/**
+ * Send a copy of a message with the given message queue.
+ * Can be called repeatedly on the same envelope.
+ *
+ * @param mq message queue
+ * @param ev the envelope with the message to send.
+ */
+void
+GNUNET_MQ_send_copy (struct GNUNET_MQ_Handle *mq,
+ const 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
/**
- * Associate the assoc_data in mq with a unique request id.
+ * Associate the assoc_data in @a 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);
+GNUNET_MQ_assoc_add (struct GNUNET_MQ_Handle *mq,
+ void *assoc_data);
/**
- * Get the data associated with a request id in a queue
+ * Get the data associated with a @a request_id in a queue
*
* @param mq the message queue with the association
* @param request_id the request id we are interested in
/**
- * Remove the association for a request id
+ * Remove the association for a @a request_id
*
* @param mq the message queue with the association
* @param request_id the request id we want to remove
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.
*
/**
- * 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.
+ * Change the closure argument in all of the `handlers` of the
+ * @a mq.
*
- * @param mq message queue
- * @param new_handlers new handlers
- * @param cls new closure for the handlers
+ * @param mq to modify
+ * @param handlers_cls new closure to use
*/
void
-GNUNET_MQ_replace_handlers (struct GNUNET_MQ_Handle *mq,
- const struct GNUNET_MQ_MessageHandler *new_handlers,
- void *cls);
+GNUNET_MQ_set_handlers_closure (struct GNUNET_MQ_Handle *mq,
+ void *handlers_cls);
/**
/**
- * 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.
+ * 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
*/
/**
- * 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.
+ * 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
+ * until #GNUNET_MQ_impl_send_continue() is called
* @return message to send, never NULL
*/
const struct GNUNET_MessageHeader *
* 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
+ * implementation state when only passing the `struct GNUNET_MQ_Handle`
* as closure.
*
* @param mq message queue with the current message
GNUNET_MQ_impl_state (struct GNUNET_MQ_Handle *mq);
-/** @} */ /* end of group mq */
-
#endif
+
+/** @} */ /* end of group mq */
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