/*
This file is part of GNUnet
- (C) 2013 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2013, 2014 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
+ 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
* @file include/gnunet_set_service.h
* @brief two-peer set operations
* @author Florian Dold
+ * @author Christian Grothoff
*/
#ifndef GNUNET_SET_SERVICE_H
#endif
#endif
-#include "platform.h"
#include "gnunet_common.h"
#include "gnunet_time_lib.h"
#include "gnunet_configuration_lib.h"
+/**
+ * Maximum size of a context message for set operation requests.
+ */
+#define GNUNET_SET_CONTEXT_MESSAGE_MAX_SIZE ((1<<16) - 1024)
+
+
/**
* Opaque handle to a set.
*/
*/
enum GNUNET_SET_OperationType
{
+ /**
+ * A purely local set that does not support any operation.
+ */
+ GNUNET_SET_OPERATION_NONE,
+
/**
* Set intersection, only return elements that are in both sets.
*/
GNUNET_SET_OPERATION_INTERSECTION,
+
/**
* Set union, return all elements that are in at least one of the sets.
*/
GNUNET_SET_OPERATION_UNION
};
+
/**
* Status for the result callback
*/
enum GNUNET_SET_Status
{
/**
- * Everything went ok.
+ * Everything went ok, we are transmitting an element of the
+ * result (in set, or to be removed from set, depending on
+ * the `enum GNUNET_SET_ResultMode`).
*/
GNUNET_SET_STATUS_OK,
+
/**
- * There was a timeout.
+ * The other peer refused to to the operation with us,
+ * or something went wrong.
*/
- GNUNET_SET_STATUS_TIMEOUT,
- /*
- * The other peer refused to to the operation with us
+ GNUNET_SET_STATUS_FAILURE,
+
+ /**
+ * Success, all elements have been returned (but the other peer
+ * might still be receiving some from us, so we are not done). Only
+ * used during UNION operation.
*/
- GNUNET_SET_STATUS_REFUSED,
- /*
- * Success, all elements have been sent.
+ GNUNET_SET_STATUS_HALF_DONE,
+
+ /**
+ * Success, all elements have been sent (and received).
*/
GNUNET_SET_STATUS_DONE
};
+
/**
* The way results are given to the client.
*/
* Client gets every element in the resulting set.
*/
GNUNET_SET_RESULT_FULL,
+
/**
* Client gets only elements that have been added to the set.
* Only works with set union.
*/
GNUNET_SET_RESULT_ADDED,
+
/**
* Client gets only elements that have been removed from the set.
* Only works with set intersection.
GNUNET_SET_RESULT_REMOVED
};
+
/**
* Element stored in a set.
*/
/**
* Application-specific element type.
*/
- uint16_t type;
+ uint16_t element_type;
/**
* Actual data of the element
*/
- void *data;
+ const void *data;
};
/**
* Continuation used for some of the set operations
*
- * @cls closure
+ * @param cls closure
*/
typedef void (*GNUNET_SET_Continuation) (void *cls);
* in the result set.
*
* @param cls closure
- * @param element a result element, only valid if status is GNUNET_SET_STATUS_OK
- * @param status see enum GNUNET_SET_Status
+ * @param element a result element, only valid if status is #GNUNET_SET_STATUS_OK
+ * @param status see `enum GNUNET_SET_Status`
*/
typedef void (*GNUNET_SET_ResultIterator) (void *cls,
- struct GNUNET_SET_Element *element,
+ const struct GNUNET_SET_Element *element,
enum GNUNET_SET_Status status);
+/**
+ * Iterator for set elements.
+ *
+ * @param cls closure
+ * @param element the current element, NULL if all elements have been
+ * iterated over
+ * @return #GNUNET_YES to continue iterating, #GNUNET_NO to stop.
+ */
+typedef int (*GNUNET_SET_ElementIterator) (void *cls,
+ const struct GNUNET_SET_Element *element);
+
/**
* Called when another peer wants to do a set operation with the
- * local peer
+ * local peer. If a listen error occurs, the @a request is NULL.
*
+ * @param cls closure
* @param other_peer the other peer
* @param context_msg message with application specific information from
* the other peer
- * @param request request from the other peer, use GNUNET_SET_accept
+ * @param request request from the other peer (never NULL), use GNUNET_SET_accept()
* to accept it, otherwise the request will be refused
- * Note that we don't use a return value here, as it is also
- * necessary to specify the set we want to do the operation with,
- * whith sometimes can be derived from the context message.
- * Also necessary to specify the timeout.
+ * Note that we can't just return value from the listen callback,
+ * as it is also necessary to specify the set we want to do the
+ * operation with, whith sometimes can be derived from the context
+ * message. It's necessary to specify the timeout.
*/
typedef void
(*GNUNET_SET_ListenCallback) (void *cls,
/**
* Add an element to the given set.
* After the element has been added (in the sense of being
- * transmitted to the set service), cont will be called.
- * Calls to add_element can be queued
+ * transmitted to the set service), @a cont will be called.
+ * Calls to #GNUNET_SET_add_element can be queued
*
* @param set set to add element to
* @param element element to add to the set
* @param cont continuation called after the element has been added
- * @param cont_cls closure for cont
+ * @param cont_cls closure for @a cont
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
+ * set is invalid (e.g. the set service crashed)
*/
-void
+int
GNUNET_SET_add_element (struct GNUNET_SET_Handle *set,
const struct GNUNET_SET_Element *element,
GNUNET_SET_Continuation cont,
* @param set set to remove element from
* @param element element to remove from the set
* @param cont continuation called after the element has been removed
- * @param cont_cls closure for cont
+ * @param cont_cls closure for @a cont
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
+ * set is invalid (e.g. the set service crashed)
*/
-void
+int
GNUNET_SET_remove_element (struct GNUNET_SET_Handle *set,
const struct GNUNET_SET_Element *element,
GNUNET_SET_Continuation cont,
/**
* Destroy the set handle, and free all associated resources.
+ * Iterations must have completed (or be explicitly canceled)
+ * before destroying the corresponding set. Operations may
+ * still be pending when a set is destroyed.
+ *
+ * @param set set to destroy
*/
void
GNUNET_SET_destroy (struct GNUNET_SET_Handle *set);
/**
- * Evaluate a set operation with our set and the set of another peer.
+ * Prepare a set operation to be evaluated with another peer.
+ * The evaluation will not start until the client provides
+ * a local set with GNUNET_SET_commit().
*
- * @param set set to use
* @param other_peer peer with the other set
* @param app_id hash for the application using the set
* @param context_msg additional information for the request
+ * @param result_mode specified how results will be returned,
+ * see `enum GNUNET_SET_ResultMode`.
* @param result_cb called on error or success
- * @param result_cls closure for result_cb
+ * @param result_cls closure for @a result_cb
* @return a handle to cancel the operation
*/
struct GNUNET_SET_OperationHandle *
-GNUNET_SET_evaluate (struct GNUNET_SET_Handle *set,
- const struct GNUNET_PeerIdentity *other_peer,
- const struct GNUNET_HashCode *app_id,
- const struct GNUNET_MessageHeader *context_msg,
- struct GNUNET_TIME_Relative timeout,
- enum GNUNET_SET_ResultMode result_mode,
- GNUNET_SET_ResultIterator result_cb,
- void *result_cls);
+GNUNET_SET_prepare (const struct GNUNET_PeerIdentity *other_peer,
+ const struct GNUNET_HashCode *app_id,
+ const struct GNUNET_MessageHeader *context_msg,
+ enum GNUNET_SET_ResultMode result_mode,
+ GNUNET_SET_ResultIterator result_cb,
+ void *result_cls);
/**
- * Wait for set operation requests for the given application id
- *
+ * Wait for set operation requests for the given application ID.
+ * If the connection to the set service is lost, the listener is
+ * re-created transparently with exponential backoff.
+ *
* @param cfg configuration to use for connecting to
* the set service
* @param operation operation we want to listen for
* @param app_id id of the application that handles set operation requests
* @param listen_cb called for each incoming request matching the operation
* and application id
- * @param listen_cls handle for listen_cb
+ * @param listen_cls handle for @a listen_cb
* @return a handle that can be used to cancel the listen operation
*/
struct GNUNET_SET_ListenHandle *
void *listen_cls);
-
/**
- * Cancel the given listen operation.
+ * Cancel the given listen operation. After calling cancel, the
+ * listen callback for this listen handle will not be called again.
*
* @param lh handle for the listen operation
*/
/**
- * Accept a request we got via GNUNET_SET_listen
+ * Accept a request we got via GNUNET_SET_listen(). Must be called during
+ * GNUNET_SET_listen(), as the `struct GNUNET_SET_Request` becomes invalid
+ * afterwards.
+ * Call GNUNET_SET_commit() to provide the local set to use for the operation,
+ * and to begin the exchange with the remote peer.
*
* @param request request to accept
- * @param set set used for the requested operation
- * @param timeout timeout for the set operation
+ * @param result_mode specified how results will be returned,
+ * see `enum GNUNET_SET_ResultMode`.
* @param result_cb callback for the results
- * @param cls closure for result_cb
+ * @param result_cls closure for @a result_cb
+ * @return a handle to cancel the operation
*/
struct GNUNET_SET_OperationHandle *
GNUNET_SET_accept (struct GNUNET_SET_Request *request,
- struct GNUNET_SET_Handle *set,
- struct GNUNET_TIME_Relative timeout,
enum GNUNET_SET_ResultMode result_mode,
GNUNET_SET_ResultIterator result_cb,
- void *cls);
+ void *result_cls);
/**
- * Cancel the given set operation.
+ * Commit a set to be used with a set operation.
+ * This function is called once we have fully constructed
+ * the set that we want to use for the operation. At this
+ * time, the P2P protocol can then begin to exchange the
+ * set information and call the result callback with the
+ * result information.
*
- * @param op set operation to cancel
+ * @param oh handle to the set operation
+ * @param set the set to use for the operation
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
+ * set is invalid (e.g. the set service crashed)
+ */
+int
+GNUNET_SET_commit (struct GNUNET_SET_OperationHandle *oh,
+ struct GNUNET_SET_Handle *set);
+
+
+/**
+ * Cancel the given set operation. May not be called after the
+ * operation's `GNUNET_SET_ResultIterator` has been called with a
+ * status that indicates error, timeout or done.
+ *
+ * @param oh set operation to cancel
*/
void
GNUNET_SET_operation_cancel (struct GNUNET_SET_OperationHandle *oh);
+/**
+ * Iterate over all elements in the given set.
+ * Note that this operation involves transferring every element of the set
+ * from the service to the client, and is thus costly.
+ * Only one iteration per set may be active at the same time.
+ *
+ * @param set the set to iterate over
+ * @param iter the iterator to call for each element
+ * @param iter_cls closure for @a iter
+ * @return #GNUNET_YES if the iteration started successfuly,
+ * #GNUNET_NO if another iteration was still active,
+ * #GNUNET_SYSERR if the set is invalid (e.g. the server crashed, disconnected)
+ */
+int
+GNUNET_SET_iterate (struct GNUNET_SET_Handle *set,
+ GNUNET_SET_ElementIterator iter,
+ void *iter_cls);
+
+/**
+ * Stop iteration over all elements in the given set. Can only
+ * be called before the iteration has "naturally" completed its
+ * turn.
+ *
+ * @param set the set to stop iterating over
+ */
+void
+GNUNET_SET_iterate_cancel (struct GNUNET_SET_Handle *set);
+
+
#if 0 /* keep Emacsens' auto-indent happy */
{
#endif
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