src/include/gnunet_datastore_service.h

   1 /*
   2      This file is part of GNUnet
   3      (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 2, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file include/gnunet_datastore_service.h
  23  * @brief API that can be used manage the
  24  *   datastore for files stored on a GNUnet node;
  25  *   note that the datastore is NOT responsible for
  26  *   on-demand encoding, that is achieved using
  27  *   a special kind of entry.
  28  * @author Christian Grothoff
  29  */
  30
  31 #ifndef GNUNET_DATASTORE_SERVICE_H
  32 #define GNUNET_DATASTORE_SERVICE_H
  33
  34 #include "gnunet_util_lib.h"
  35 #include "gnunet_block_lib.h"
  36
  37 #ifdef __cplusplus
  38 extern "C"
  39 {
  40 #if 0                           /* keep Emacsens' auto-indent happy */
  41 }
  42 #endif
  43 #endif
  44
  45 /**
  46  * Entry in the queue.
  47  */
  48 struct GNUNET_DATASTORE_QueueEntry;
  49
  50 /**
  51  * Handle to the datastore service.
  52  */
  53 struct GNUNET_DATASTORE_Handle;
  54
  55 /**
  56  * Maximum size of a value that can be stored in the datastore.
  57  */
  58 #define GNUNET_DATASTORE_MAX_VALUE_SIZE 65536
  59
  60 /**
  61  * Connect to the datastore service.
  62  *
  63  * @param cfg configuration to use
  64  * @return handle to use to access the service
  65  */
  66 struct GNUNET_DATASTORE_Handle *GNUNET_DATASTORE_connect (const struct
  67                                                           GNUNET_CONFIGURATION_Handle
  68                                                           *cfg);
  69
  70
  71 /**
  72  * Disconnect from the datastore service (and free
  73  * associated resources).
  74  *
  75  * @param h handle to the datastore
  76  * @param drop set to GNUNET_YES to delete all data in datastore (!)
  77  */
  78 void GNUNET_DATASTORE_disconnect (struct GNUNET_DATASTORE_Handle *h, int drop);
  79
  80
  81 /**
  82  * Continuation called to notify client about result of the
  83  * operation.
  84  *
  85  * @param cls closure
  86  * @param success GNUNET_SYSERR on failure (including timeout/queue drop)
  87  *                GNUNET_NO if content was already there
  88  *                GNUNET_YES (or other positive value) on success
  89  * @param msg NULL on success, otherwise an error message
  90  */
  91 typedef void (*GNUNET_DATASTORE_ContinuationWithStatus) (void *cls,
  92                                                          int32_t success,
  93                                                          const char *msg);
  94
  95
  96 /**
  97  * Reserve space in the datastore.  This function should be used
  98  * to avoid "out of space" failures during a longer sequence of "put"
  99  * operations (for example, when a file is being inserted).
 100  *
 101  * @param h handle to the datastore
 102  * @param amount how much space (in bytes) should be reserved (for content only)
 103  * @param entries how many entries will be created (to calculate per-entry overhead)
 104  * @param queue_priority ranking of this request in the priority queue
 105  * @param max_queue_size at what queue size should this request be dropped
 106  *        (if other requests of higher priority are in the queue)
 107  * @param timeout how long to wait at most for a response (or before dying in queue)
 108  * @param cont continuation to call when done; "success" will be set to
 109  *             a positive reservation value if space could be reserved.
 110  * @param cont_cls closure for cont
 111  * @return NULL if the entry was not queued, otherwise a handle that can be used to
 112  *         cancel; note that even if NULL is returned, the callback will be invoked
 113  *         (or rather, will already have been invoked)
 114  */
 115 struct GNUNET_DATASTORE_QueueEntry *GNUNET_DATASTORE_reserve (struct
 116                                                               GNUNET_DATASTORE_Handle
 117                                                               *h,
 118                                                               uint64_t amount,
 119                                                               uint32_t entries,
 120                                                               unsigned int
 121                                                               queue_priority,
 122                                                               unsigned int
 123                                                               max_queue_size,
 124                                                               struct
 125                                                               GNUNET_TIME_Relative
 126                                                               timeout,
 127                                                               GNUNET_DATASTORE_ContinuationWithStatus
 128                                                               cont,
 129                                                               void *cont_cls);
 130
 131
 132 /**
 133  * Store an item in the datastore.  If the item is already present,
 134  * the priorities and replication values are summed up and the higher
 135  * expiration time and lower anonymity level is used.
 136  *
 137  * @param h handle to the datastore
 138  * @param rid reservation ID to use (from "reserve"); use 0 if no
 139  *            prior reservation was made
 140  * @param key key for the value
 141  * @param size number of bytes in data
 142  * @param data content stored
 143  * @param type type of the content
 144  * @param priority priority of the content
 145  * @param anonymity anonymity-level for the content
 146  * @param replication how often should the content be replicated to other peers?
 147  * @param expiration expiration time for the content
 148  * @param queue_priority ranking of this request in the priority queue
 149  * @param max_queue_size at what queue size should this request be dropped
 150  *        (if other requests of higher priority are in the queue)
 151  * @param timeout timeout for the operation
 152  * @param cont continuation to call when done
 153  * @param cont_cls closure for cont
 154  * @return NULL if the entry was not queued, otherwise a handle that can be used to
 155  *         cancel; note that even if NULL is returned, the callback will be invoked
 156  *         (or rather, will already have been invoked)
 157  */
 158 struct GNUNET_DATASTORE_QueueEntry *GNUNET_DATASTORE_put (struct
 159                                                           GNUNET_DATASTORE_Handle
 160                                                           *h, uint32_t rid,
 161                                                           const GNUNET_HashCode
 162                                                           * key, size_t size,
 163                                                           const void *data,
 164                                                           enum GNUNET_BLOCK_Type
 165                                                           type,
 166                                                           uint32_t priority,
 167                                                           uint32_t anonymity,
 168                                                           uint32_t replication,
 169                                                           struct
 170                                                           GNUNET_TIME_Absolute
 171                                                           expiration,
 172                                                           unsigned int
 173                                                           queue_priority,
 174                                                           unsigned int
 175                                                           max_queue_size,
 176                                                           struct
 177                                                           GNUNET_TIME_Relative
 178                                                           timeout,
 179                                                           GNUNET_DATASTORE_ContinuationWithStatus
 180                                                           cont, void *cont_cls);
 181
 182
 183 /**
 184  * Signal that all of the data for which a reservation was made has
 185  * been stored and that whatever excess space might have been reserved
 186  * can now be released.
 187  *
 188  * @param h handle to the datastore
 189  * @param rid reservation ID (value of "success" in original continuation
 190  *        from the "reserve" function).
 191  * @param queue_priority ranking of this request in the priority queue
 192  * @param max_queue_size at what queue size should this request be dropped
 193  *        (if other requests of higher priority are in the queue)
 194  * @param queue_priority ranking of this request in the priority queue
 195  * @param max_queue_size at what queue size should this request be dropped
 196  *        (if other requests of higher priority are in the queue)
 197  * @param timeout how long to wait at most for a response
 198  * @param cont continuation to call when done
 199  * @param cont_cls closure for cont
 200  * @return NULL if the entry was not queued, otherwise a handle that can be used to
 201  *         cancel; note that even if NULL is returned, the callback will be invoked
 202  *         (or rather, will already have been invoked)
 203  */
 204 struct GNUNET_DATASTORE_QueueEntry *GNUNET_DATASTORE_release_reserve (struct
 205                                                                       GNUNET_DATASTORE_Handle
 206                                                                       *h,
 207                                                                       uint32_t
 208                                                                       rid,
 209                                                                       unsigned
 210                                                                       int
 211                                                                       queue_priority,
 212                                                                       unsigned
 213                                                                       int
 214                                                                       max_queue_size,
 215                                                                       struct
 216                                                                       GNUNET_TIME_Relative
 217                                                                       timeout,
 218                                                                       GNUNET_DATASTORE_ContinuationWithStatus
 219                                                                       cont,
 220                                                                       void
 221                                                                       *cont_cls);
 222
 223
 224 /**
 225  * Update a value in the datastore.
 226  *
 227  * @param h handle to the datastore
 228  * @param uid identifier for the value
 229  * @param priority how much to increase the priority of the value
 230  * @param expiration new expiration value should be MAX of existing and this argument
 231  * @param queue_priority ranking of this request in the priority queue
 232  * @param max_queue_size at what queue size should this request be dropped
 233  *        (if other requests of higher priority are in the queue)
 234  * @param timeout how long to wait at most for a response
 235  * @param cont continuation to call when done
 236  * @param cont_cls closure for cont
 237  * @return NULL if the entry was not queued, otherwise a handle that can be used to
 238  *         cancel; note that even if NULL is returned, the callback will be invoked
 239  *         (or rather, will already have been invoked)
 240  */
 241 struct GNUNET_DATASTORE_QueueEntry *GNUNET_DATASTORE_update (struct
 242                                                              GNUNET_DATASTORE_Handle
 243                                                              *h, uint64_t uid,
 244                                                              uint32_t priority,
 245                                                              struct
 246                                                              GNUNET_TIME_Absolute
 247                                                              expiration,
 248                                                              unsigned int
 249                                                              queue_priority,
 250                                                              unsigned int
 251                                                              max_queue_size,
 252                                                              struct
 253                                                              GNUNET_TIME_Relative
 254                                                              timeout,
 255                                                              GNUNET_DATASTORE_ContinuationWithStatus
 256                                                              cont,
 257                                                              void *cont_cls);
 258
 259
 260 /**
 261  * Explicitly remove some content from the database.
 262  * The "cont"inuation will be called with status
 263  * "GNUNET_OK" if content was removed, "GNUNET_NO"
 264  * if no matching entry was found and "GNUNET_SYSERR"
 265  * on all other types of errors.
 266  *
 267  * @param h handle to the datastore
 268  * @param key key for the value
 269  * @param size number of bytes in data
 270  * @param data content stored
 271  * @param queue_priority ranking of this request in the priority queue
 272  * @param max_queue_size at what queue size should this request be dropped
 273  *        (if other requests of higher priority are in the queue)
 274  * @param timeout how long to wait at most for a response
 275  * @param cont continuation to call when done
 276  * @param cont_cls closure for cont
 277  * @return NULL if the entry was not queued, otherwise a handle that can be used to
 278  *         cancel; note that even if NULL is returned, the callback will be invoked
 279  *         (or rather, will already have been invoked)
 280  */
 281 struct GNUNET_DATASTORE_QueueEntry *GNUNET_DATASTORE_remove (struct
 282                                                              GNUNET_DATASTORE_Handle
 283                                                              *h,
 284                                                              const
 285                                                              GNUNET_HashCode *
 286                                                              key, size_t size,
 287                                                              const void *data,
 288                                                              unsigned int
 289                                                              queue_priority,
 290                                                              unsigned int
 291                                                              max_queue_size,
 292                                                              struct
 293                                                              GNUNET_TIME_Relative
 294                                                              timeout,
 295                                                              GNUNET_DATASTORE_ContinuationWithStatus
 296                                                              cont,
 297                                                              void *cont_cls);
 298
 299
 300 /**
 301  * Process a datum that was stored in the datastore.
 302  *
 303  * @param cls closure
 304  * @param key key for the content
 305  * @param size number of bytes in data
 306  * @param data content stored
 307  * @param type type of the content
 308  * @param priority priority of the content
 309  * @param anonymity anonymity-level for the content
 310  * @param expiration expiration time for the content
 311  * @param uid unique identifier for the datum;
 312  *        maybe 0 if no unique identifier is available
 313  */
 314 typedef void (*GNUNET_DATASTORE_DatumProcessor) (void *cls,
 315                                                  const GNUNET_HashCode * key,
 316                                                  size_t size, const void *data,
 317                                                  enum GNUNET_BLOCK_Type type,
 318                                                  uint32_t priority,
 319                                                  uint32_t anonymity,
 320                                                  struct GNUNET_TIME_Absolute
 321                                                  expiration, uint64_t uid);
 322
 323
 324 /**
 325  * Get a result for a particular key from the datastore.  The processor
 326  * will only be called once.
 327  *
 328  * @param h handle to the datastore
 329  * @param offset offset of the result (modulo num-results); set to
 330  *               a random 64-bit value initially; then increment by
 331  *               one each time; detect that all results have been found by uid
 332  *               being again the first uid ever returned.
 333  * @param key maybe NULL (to match all entries)
 334  * @param type desired type, 0 for any
 335  * @param queue_priority ranking of this request in the priority queue
 336  * @param max_queue_size at what queue size should this request be dropped
 337  *        (if other requests of higher priority are in the queue)
 338  * @param timeout how long to wait at most for a response
 339  * @param proc function to call on each matching value;
 340  *        will be called once with a NULL value at the end
 341  * @param proc_cls closure for proc
 342  * @return NULL if the entry was not queued, otherwise a handle that can be used to
 343  *         cancel
 344  */
 345 struct GNUNET_DATASTORE_QueueEntry *GNUNET_DATASTORE_get_key (struct
 346                                                               GNUNET_DATASTORE_Handle
 347                                                               *h,
 348                                                               uint64_t offset,
 349                                                               const
 350                                                               GNUNET_HashCode *
 351                                                               key,
 352                                                               enum
 353                                                               GNUNET_BLOCK_Type
 354                                                               type,
 355                                                               unsigned int
 356                                                               queue_priority,
 357                                                               unsigned int
 358                                                               max_queue_size,
 359                                                               struct
 360                                                               GNUNET_TIME_Relative
 361                                                               timeout,
 362                                                               GNUNET_DATASTORE_DatumProcessor
 363                                                               proc,
 364                                                               void *proc_cls);
 365
 366
 367 /**
 368  * Get a single zero-anonymity value from the datastore.
 369  * Note that some implementations can ignore the 'offset' and
 370  * instead return a random zero-anonymity value.  In that case,
 371  * detecting the wrap-around based on a repeating UID is at best
 372  * probabilistic.
 373  *
 374  * @param h handle to the datastore
 375  * @param offset offset of the result (modulo num-results); set to
 376  *               a random 64-bit value initially; then increment by
 377  *               one each time; detect that all results have been found by uid
 378  *               being again the first uid ever returned.
 379  * @param queue_priority ranking of this request in the priority queue
 380  * @param max_queue_size at what queue size should this request be dropped
 381  *        (if other requests of higher priority are in the queue)
 382  * @param timeout how long to wait at most for a response
 383  * @param type allowed type for the operation (never zero)
 384  * @param proc function to call on a random value; it
 385  *        will be called once with a value (if available)
 386  *        or with NULL if none value exists.
 387  * @param proc_cls closure for proc
 388  * @return NULL if the entry was not queued, otherwise a handle that can be used to
 389  *         cancel
 390  */
 391 struct GNUNET_DATASTORE_QueueEntry *GNUNET_DATASTORE_get_zero_anonymity (struct
 392                                                                          GNUNET_DATASTORE_Handle
 393                                                                          *h,
 394                                                                          uint64_t
 395                                                                          offset,
 396                                                                          unsigned
 397                                                                          int
 398                                                                          queue_priority,
 399                                                                          unsigned
 400                                                                          int
 401                                                                          max_queue_size,
 402                                                                          struct
 403                                                                          GNUNET_TIME_Relative
 404                                                                          timeout,
 405                                                                          enum
 406                                                                          GNUNET_BLOCK_Type
 407                                                                          type,
 408                                                                          GNUNET_DATASTORE_DatumProcessor
 409                                                                          proc,
 410                                                                          void
 411                                                                          *proc_cls);
 412
 413
 414 /**
 415  * Get a random value from the datastore for content replication.
 416  * Returns a single, random value among those with the highest
 417  * replication score, lowering positive replication scores by one for
 418  * the chosen value (if only content with a replication score exists,
 419  * a random value is returned and replication scores are not changed).
 420  *
 421  * @param h handle to the datastore
 422  * @param queue_priority ranking of this request in the priority queue
 423  * @param max_queue_size at what queue size should this request be dropped
 424  *        (if other requests of higher priority are in the queue)
 425  * @param timeout how long to wait at most for a response
 426  * @param proc function to call on a random value; it
 427  *        will be called once with a value (if available)
 428  *        and always once with a value of NULL.
 429  * @param proc_cls closure for proc
 430  * @return NULL if the entry was not queued, otherwise a handle that can be used to
 431  *         cancel
 432  */
 433 struct GNUNET_DATASTORE_QueueEntry *GNUNET_DATASTORE_get_for_replication (struct
 434                                                                           GNUNET_DATASTORE_Handle
 435                                                                           *h,
 436                                                                           unsigned
 437                                                                           int
 438                                                                           queue_priority,
 439                                                                           unsigned
 440                                                                           int
 441                                                                           max_queue_size,
 442                                                                           struct
 443                                                                           GNUNET_TIME_Relative
 444                                                                           timeout,
 445                                                                           GNUNET_DATASTORE_DatumProcessor
 446                                                                           proc,
 447                                                                           void
 448                                                                           *proc_cls);
 449
 450
 451
 452 /**
 453  * Cancel a datastore operation.  The final callback from the
 454  * operation must not have been done yet.
 455  *
 456  * @param qe operation to cancel
 457  */
 458 void GNUNET_DATASTORE_cancel (struct GNUNET_DATASTORE_QueueEntry *qe);
 459
 460
 461 #if 0                           /* keep Emacsens' auto-indent happy */
 462 {
 463 #endif
 464 #ifdef __cplusplus
 465 }
 466 #endif
 467
 468 /* end of gnunet_datastore_service.h */
 469 #endif