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diff --git a/src/service/fs/gnunet-service-fs_pr.h b/src/service/fs/gnunet-service-fs_pr.h
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+/*
+     This file is part of GNUnet.
+     Copyright (C) 2009, 2010, 2011 GNUnet e.V.
+
+     GNUnet is free software: you can redistribute it and/or modify it
+     under the terms of the GNU Affero General Public License as published
+     by the Free Software Foundation, either version 3 of the License,
+     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
+     Affero General Public License for more details.
+
+     You should have received a copy of the GNU Affero General Public License
+     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file fs/gnunet-service-fs_pr.h
+ * @brief API to handle pending requests
+ * @author Christian Grothoff
+ */
+#ifndef GNUNET_SERVICE_FS_PR_H
+#define GNUNET_SERVICE_FS_PR_H
+
+#include "gnunet-service-fs.h"
+
+
+/**
+ * Options for pending requests (bits to be ORed).
+ */
+enum GSF_PendingRequestOptions
+{
+  /**
+   * No special options (P2P-default).
+   */
+  GSF_PRO_DEFAULTS = 0,
+
+  /**
+   * Request must only be processed locally.
+   */
+  GSF_PRO_LOCAL_ONLY = 1,
+
+  /**
+   * Request must only be forwarded (no routing)
+   */
+  GSF_PRO_FORWARD_ONLY = 2,
+
+  /**
+   * Request persists indefinitely (no expiration).
+   */
+  GSF_PRO_REQUEST_NEVER_EXPIRES = 4,
+
+  /**
+   * Request is allowed to refresh bloomfilter and change mingle value.
+   */
+  GSF_PRO_BLOOMFILTER_FULL_REFRESH = 8,
+
+  /**
+   * Request priority is allowed to be exceeded.
+   */
+  GSF_PRO_PRIORITY_UNLIMITED = 16,
+
+  /**
+   * Option mask for typical local requests.
+   */
+  GSF_PRO_LOCAL_REQUEST =
+    (GSF_PRO_BLOOMFILTER_FULL_REFRESH | GSF_PRO_PRIORITY_UNLIMITED
+     | GSF_PRO_REQUEST_NEVER_EXPIRES)
+};
+
+
+/**
+ * Public data (in the sense of not encapsulated within
+ * 'gnunet-service-fs_pr', not in the sense of network-wide
+ * known) associated with each pending request.
+ */
+struct GSF_PendingRequestData
+{
+  /**
+   * Primary query hash for this request.
+   */
+  struct GNUNET_HashCode query;
+
+  /**
+   * Identity of a peer hosting the content, otherwise NULl.
+   * Allocated after struct only if needed. Do not free!
+   */
+  const struct GNUNET_PeerIdentity *target;
+
+  /**
+   * Fields for the plan module to track a DLL with the request.
+   */
+  struct GSF_PendingRequestPlanBijection *pr_head;
+
+  /**
+   * Fields for the plan module to track a DLL with the request.
+   */
+  struct GSF_PendingRequestPlanBijection *pr_tail;
+
+  /**
+   * Current TTL for the request.
+   */
+  struct GNUNET_TIME_Absolute ttl;
+
+  /**
+   * When did we start with the request.
+   */
+  struct GNUNET_TIME_Absolute start_time;
+
+  /**
+   * Desired anonymity level.
+   */
+  uint32_t anonymity_level;
+
+  /**
+   * Priority that this request (still) has for us.
+   */
+  uint32_t priority;
+
+  /**
+   * Priority that this request (originally) had for us.
+   */
+  uint32_t original_priority;
+
+  /**
+   * Counter for how often this request has been transmitted (estimate,
+   * because we might have the same request pending for multiple clients,
+   * and of course because a transmission may have failed at a lower
+   * layer).
+   */
+  uint32_t num_transmissions;
+
+  /**
+   * How much respect did we (in total) offer for this request so far (estimate,
+   * because we might have the same request pending for multiple clients,
+   * and of course because a transmission may have failed at a lower
+   * layer).
+   */
+  uint32_t respect_offered;
+
+  /**
+   * Options for the request.
+   */
+  enum GSF_PendingRequestOptions options;
+
+  /**
+   * Type of the requested block.
+   */
+  enum GNUNET_BLOCK_Type type;
+
+  /**
+   * Number of results we have found for this request so far.
+   */
+  unsigned int results_found;
+
+  /**
+   * Has this request been started yet (local/p2p operations)?  Or are
+   * we still constructing it?
+   */
+  int has_started;
+};
+
+
+/**
+ * Handle a reply to a pending request.  Also called if a request
+ * expires (then with data == NULL).  The handler may be called
+ * many times (depending on the request type), but will not be
+ * called during or after a call to GSF_pending_request_cancel
+ * and will also not be called anymore after a call signalling
+ * expiration.
+ *
+ * @param cls user-specified closure
+ * @param eval evaluation of the result
+ * @param pr handle to the original pending request
+ * @param reply_anonymity_level anonymity level for the reply, UINT32_MAX for "unknown"
+ * @param expiration when does @a data expire?
+ * @param last_transmission the last time we've tried to get this block (FOREVER if unknown)
+ * @param type type of the block
+ * @param data response data, NULL on request expiration
+ * @param data_len number of bytes in @a data
+ */
+typedef void
+(*GSF_PendingRequestReplyHandler) (
+  void *cls,
+  enum GNUNET_BLOCK_ReplyEvaluationResult eval,
+  struct GSF_PendingRequest *pr,
+  uint32_t reply_anonymity_level,
+  struct GNUNET_TIME_Absolute expiration,
+  struct GNUNET_TIME_Absolute
+  last_transmission,
+  enum GNUNET_BLOCK_Type type,
+  const void *data,
+  size_t data_len);
+
+
+/**
+ * Create a new pending request.
+ *
+ * @param options request options
+ * @param type type of the block that is being requested
+ * @param query key for the lookup
+ * @param target preferred target for the request, NULL for none
+ * @param bf_data raw data for bloom filter for known replies, can be NULL
+ * @param bf_size number of bytes in bf_data
+ * @param anonymity_level desired anonymity level
+ * @param priority maximum outgoing cumulative request priority to use
+ * @param ttl current time-to-live for the request
+ * @param sender_pid peer ID to use for the sender when forwarding, 0 for none;
+ *                   reference counter is taken over by this function
+ * @param origin_pid peer ID of origin of query (do not loop back)
+ * @param replies_seen hash codes of known local replies
+ * @param replies_seen_count size of the 'replies_seen' array
+ * @param rh handle to call when we get a reply
+ * @param rh_cls closure for rh
+ * @return handle for the new pending request
+ */
+struct GSF_PendingRequest *
+GSF_pending_request_create_ (enum GSF_PendingRequestOptions options,
+                             enum GNUNET_BLOCK_Type type,
+                             const struct GNUNET_HashCode *query,
+                             const struct GNUNET_PeerIdentity *target,
+                             const char *bf_data,
+                             size_t bf_size,
+                             uint32_t anonymity_level,
+                             uint32_t priority,
+                             int32_t ttl,
+                             GNUNET_PEER_Id sender_pid,
+                             GNUNET_PEER_Id origin_pid,
+                             const struct GNUNET_HashCode *replies_seen,
+                             unsigned int replies_seen_count,
+                             GSF_PendingRequestReplyHandler rh,
+                             void *rh_cls);
+
+
+/**
+ * Update a given pending request with additional replies
+ * that have been seen.
+ *
+ * @param pr request to update
+ * @param replies_seen hash codes of replies that we've seen
+ * @param replies_seen_count size of the @a replies_seen array
+ */
+void
+GSF_pending_request_update_ (struct GSF_PendingRequest *pr,
+                             const struct GNUNET_HashCode *replies_seen,
+                             unsigned int replies_seen_count);
+
+
+/**
+ * Obtain the public data associated with a pending request
+ *
+ * @param pr pending request
+ * @return associated public data
+ */
+struct GSF_PendingRequestData *
+GSF_pending_request_get_data_ (struct GSF_PendingRequest *pr);
+
+
+/**
+ * Check if the given request is still active.
+ *
+ * @param pr pending request
+ * @return #GNUNET_YES if the request is still active
+ */
+int
+GSF_pending_request_test_active_ (struct GSF_PendingRequest *pr);
+
+
+/**
+ * Test if two pending requests are compatible (would generate
+ * the same query modulo filters and should thus be processed
+ * jointly).
+ *
+ * @param pra a pending request
+ * @param prb another pending request
+ * @return #GNUNET_OK if the requests are compatible
+ */
+int
+GSF_pending_request_is_compatible_ (struct GSF_PendingRequest *pra,
+                                    struct GSF_PendingRequest *prb);
+
+
+/**
+ * Generate the message corresponding to the given pending request for
+ * transmission to other peers.
+ *
+ * @param pr request to generate the message for
+ * @return envelope with the request message
+ */
+struct GNUNET_MQ_Envelope *
+GSF_pending_request_get_message_ (struct GSF_PendingRequest *pr);
+
+
+/**
+ * Explicitly cancel a pending request.
+ *
+ * @param pr request to cancel
+ * @param full_cleanup fully purge the request
+ */
+void
+GSF_pending_request_cancel_ (struct GSF_PendingRequest *pr,
+                             int full_cleanup);
+
+
+/**
+ * Signature of function called on each request.
+ * (Note: 'subtype' of GNUNET_CONTAINER_HashMapIterator).
+ *
+ * @param cls closure
+ * @param key query for the request
+ * @param pr handle to the pending request
+ * @return #GNUNET_YES to continue to iterate
+ */
+typedef int
+(*GSF_PendingRequestIterator) (void *cls,
+                               const struct GNUNET_HashCode *key,
+                               struct GSF_PendingRequest *pr);
+
+
+/**
+ * Iterate over all pending requests.
+ *
+ * @param it function to call for each request
+ * @param cls closure for it
+ */
+void
+GSF_iterate_pending_requests_ (GSF_PendingRequestIterator it,
+                               void *cls);
+
+
+/**
+ * Handle P2P "CONTENT" message.  Checks that the message is
+ * well-formed and then checks if there are any pending requests for
+ * this content and possibly passes it on (to local clients or other
+ * peers).  Does NOT perform migration (content caching at this peer).
+ *
+ * @param cls the other peer involved (sender)
+ * @param put the actual message
+ */
+void
+handle_p2p_put (void *cls,
+                const struct PutMessage *put);
+
+
+/**
+ * Consider looking up the data in the DHT (anonymity-level permitting).
+ *
+ * @param pr the pending request to process
+ */
+void
+GSF_dht_lookup_ (struct GSF_PendingRequest *pr);
+
+
+/**
+ * Consider downloading via cadet (if possible)
+ *
+ * @param pr the pending request to process
+ */
+void
+GSF_cadet_lookup_ (struct GSF_PendingRequest *pr);
+
+
+/**
+ * Function to be called after we're done processing
+ * replies from the local lookup.
+ *
+ * @param cls closure
+ * @param pr the pending request we were processing
+ * @param result final datastore lookup result
+ */
+typedef void
+(*GSF_LocalLookupContinuation) (
+  void *cls,
+  struct GSF_PendingRequest *pr,
+  enum GNUNET_BLOCK_ReplyEvaluationResult result);
+
+
+/**
+ * Look up the request in the local datastore.
+ *
+ * @param pr the pending request to process
+ * @param cont function to call at the end
+ * @param cont_cls closure for @a cont
+ */
+void
+GSF_local_lookup_ (struct GSF_PendingRequest *pr,
+                   GSF_LocalLookupContinuation cont,
+                   void *cont_cls);
+
+
+/**
+ * Is the given target a legitimate peer for forwarding the given request?
+ *
+ * @param pr request
+ * @param target
+ * @return #GNUNET_YES if this request could be forwarded to the given peer
+ */
+int
+GSF_pending_request_test_target_ (struct GSF_PendingRequest *pr,
+                                  const struct GNUNET_PeerIdentity *target);
+
+
+/**
+ * Setup the subsystem.
+ */
+void
+GSF_pending_request_init_ (void);
+
+
+/**
+ * Shutdown the subsystem.
+ */
+void
+GSF_pending_request_done_ (void);
+
+
+#endif
+/* end of gnunet-service-fs_pr.h */