/*
This file is part of GNUnet.
- (C) 2012 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
- by the Free Software Foundation; either version 2, or (at your
+ 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
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.
+ Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA.
*/
/**
* @author Florian Dold
- * @file include/gnunet_mq_lib.h
- * @brief 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
#define GNUNET_MQ_H
-#include "gnunet_common.h"
-
/**
* Allocate an envelope, with extra space allocated after the space needed
* @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))
+#define GNUNET_MQ_msg_extra(mvar, esize, type) GNUNET_MQ_msg_(((struct GNUNET_MessageHeader**) &(mvar)), (esize) + sizeof *(mvar), (type))
/**
* Allocate a GNUNET_MQ_Envelope.
* @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 'var' does not have any space after the message struct
+ * 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.
+ * 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
*/
-struct GNUNET_MessageHeader *
-GNUNET_MQ_extract_nested_mh_ (const struct GNUNET_MessageHeader *mh, uint16_t base_size);
+const struct GNUNET_MessageHeader *
+GNUNET_MQ_extract_nested_mh_ (const struct GNUNET_MessageHeader *mh,
+ uint16_t base_size);
+
+
+/**
+ * Opaque handle to an envelope.
+ */
+struct GNUNET_MQ_Envelope;
/**
- * Implementation of the GNUNET_MQ_msg_nested_mh macro.
+ * 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 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,
+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.
+ * Error codes for the queue.
*/
-struct GNUNET_MQ_Envelope;
-
enum GNUNET_MQ_Error
{
+ /**
+ * 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_WRITE = 2,
- GNUNET_MQ_ERROR_TIMEOUT = 4
+
+ /**
+ * FIXME: document!
+ */
+ 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.
/**
* Signature of functions implementing the
* destruction of a message queue.
- * Implementations must not free 'mq', but should
- * take care of 'impl_state'.
- *
+ * 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);
+(*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);
+(*GNUNET_MQ_CancelImpl) (struct GNUNET_MQ_Handle *mq,
+ void *impl_state);
/**
* 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
-(*GNUNET_MQ_ErrorHandler) (void *cls, enum GNUNET_MQ_Error error);
+(*GNUNET_MQ_ErrorHandler) (void *cls,
+ enum GNUNET_MQ_Error error);
/**
struct GNUNET_MQ_MessageHandler
{
/**
- * Callback, called every time a new message of
- * the specified type has been receied.
+ * 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 @e type has been receied.
+ * The closure given to @e mv will be this struct (not @e ctx).
*/
GNUNET_MQ_MessageCallback cb;
+ /**
+ * Closure for @e mv and @e cb.
+ */
+ void *cls;
/**
- * Type of the message this handler covers.
+ * 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)
+ * { ... }
+ *
+ * struct GNUNET_MQ_MessageHandler handlers[] = {
+ * GNUNET_MQ_hd_fixed_size(test_message,
+ * GNUNET_MESSAGE_TYPE_TEST,
+ * struct GNUNET_MessageTest,
+ * "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)
+ * @param ctx context for the callbacks
+ */
+#define GNUNET_MQ_hd_fixed_size(name,code,str,ctx) \
+ ({ \
+ void (*_cb)(void *cls, const str *msg) = &handle_##name; \
+ ((struct GNUNET_MQ_MessageHandler) { \
+ NULL, (GNUNET_MQ_MessageCallback) _cb, \
+ (ctx), (code), sizeof (str) }); \
+ })
+
+
+/**
+ * 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
+ * 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[] = {
+ * GNUNET_MQ_hd_var_size(test_message,
+ * GNUNET_MESSAGE_TYPE_TEST,
+ * struct GNUNET_MessageTest,
+ * "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)
+ * @param ctx context for the callbacks
+ */
+#define GNUNET_MQ_hd_var_size(name,code,str,ctx) \
+ ({ \
+ int (*_mv)(void *cls, const str *msg) = &check_##name; \
+ void (*_cb)(void *cls, const str *msg) = &handle_##name; \
+ ((struct GNUNET_MQ_MessageHandler) \
+ { (GNUNET_MQ_MessageValidationCallback) _mv, \
+ (GNUNET_MQ_MessageCallback) _cb, \
+ (ctx), (code), sizeof (str) }); \
+ })
+
/**
* 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);
+GNUNET_MQ_msg_ (struct GNUNET_MessageHeader **mhp,
+ uint16_t size,
+ 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);
/**
/**
- * Send a message with the give message queue.
+ * Function to obtain the current envelope
+ * from within #GNUNET_MQ_SendImpl implementations.
+ *
+ * @param mq message queue to interrogate
+ * @return the current envelope
+ */
+struct GNUNET_MQ_Envelope *
+GNUNET_MQ_get_current_envelope (struct GNUNET_MQ_Handle *mq);
+
+
+/**
+ * Function to obtain the last envelope in the queue.
+ *
+ * @param mq message queue to interrogate
+ * @return the last envelope in the queue
+ */
+struct GNUNET_MQ_Envelope *
+GNUNET_MQ_get_last_envelope (struct GNUNET_MQ_Handle *mq);
+
+
+/**
+ * Set application-specific options for this envelope.
+ * Overrides the options set for the queue with
+ * #GNUNET_MQ_set_options() for this message only.
+ *
+ * @param env message to set options for
+ * @param flags flags to use (meaning is queue-specific)
+ * @param extra additional buffer for further data (also queue-specific)
+ */
+void
+GNUNET_MQ_env_set_options (struct GNUNET_MQ_Envelope *env,
+ uint64_t flags,
+ const void *extra);
+
+
+/**
+ * Get application-specific options for this envelope.
+ *
+ * @param env message to set options for
+ * @param[out] flags set to flags to use (meaning is queue-specific)
+ * @return extra additional buffer for further data (also queue-specific)
+ */
+const void *
+GNUNET_MQ_env_get_options (struct GNUNET_MQ_Envelope *env,
+ uint64_t *flags);
+
+
+/**
+ * Set application-specific options for this queue.
+ *
+ * @param mq message queue to set options for
+ * @param flags flags to use (meaning is queue-specific)
+ * @param extra additional buffer for further data (also queue-specific)
+ */
+void
+GNUNET_MQ_set_options (struct GNUNET_MQ_Handle *mq,
+ uint64_t flags,
+ const void *extra);
+
+
+/**
+ * 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
+ * @param ev the envelope with the message to send.
+ */
+void
+GNUNET_MQ_send (struct GNUNET_MQ_Handle *mq,
+ 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 (struct GNUNET_MQ_Handle *mq, struct GNUNET_MQ_Envelope *ev);
+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 callback has been called
+ * 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
*/
/**
- * 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
* @return the associated data
*/
void *
-GNUNET_MQ_assoc_get (struct GNUNET_MQ_Handle *mq, uint32_t request_id);
+GNUNET_MQ_assoc_get (struct GNUNET_MQ_Handle *mq,
+ uint32_t request_id);
/**
- * 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
* @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_STREAM_Socket.
- *
- * @param client the client
- * @return the message queue
- */
-struct GNUNET_MQ_Handle *
-GNUNET_MQ_queue_for_server_client (struct GNUNET_SERVER_Client *client);
+GNUNET_MQ_assoc_remove (struct GNUNET_MQ_Handle *mq,
+ uint32_t request_id);
/**
* @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 'send' and 'destroy'
+ * @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
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.
+ * 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.
- * 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
+ * @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 *
* 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);
-/**
- * Mark the current message as irrevocably sent, but do not
- * proceed with sending the next message.
- * Will call the appropriate GNUNET_MQ_NotifyCallback, if any.
- *
- * @param mq message queue
- */
-void
-GNUNET_MQ_impl_send_commit (struct GNUNET_MQ_Handle *mq);
-
#endif
+
+/** @} */ /* end of group mq */
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