src/t_set.c

   1 #include "redis.h"
   2
   3 /*-----------------------------------------------------------------------------
   4  * Set Commands
   5  *----------------------------------------------------------------------------*/
   6
   7 /* Factory method to return a set that *can* hold "value". When the object has
   8  * an integer-encodable value, an intset will be returned. Otherwise a regular
   9  * hash table. */
  10 robj *setTypeCreate(robj *value) {
  11     if (isObjectRepresentableAsLongLong(value,NULL) == REDIS_OK)
  12         return createIntsetObject();
  13     return createSetObject();
  14 }
  15
  16 int setTypeAdd(robj *subject, robj *value) {
  17     long long llval;
  18     if (subject->encoding == REDIS_ENCODING_HT) {
  19         if (dictAdd(subject->ptr,value,NULL) == DICT_OK) {
  20             incrRefCount(value);
  21             return 1;
  22         }
  23     } else if (subject->encoding == REDIS_ENCODING_INTSET) {
  24         if (isObjectRepresentableAsLongLong(value,&llval) == REDIS_OK) {
  25             uint8_t success = 0;
  26             subject->ptr = intsetAdd(subject->ptr,llval,&success);
  27             if (success) {
  28                 /* Convert to regular set when the intset contains
  29                  * too many entries. */
  30                 if (intsetLen(subject->ptr) > server.set_max_intset_entries)
  31                     setTypeConvert(subject,REDIS_ENCODING_HT);
  32                 return 1;
  33             }
  34         } else {
  35             /* Failed to get integer from object, convert to regular set. */
  36             setTypeConvert(subject,REDIS_ENCODING_HT);
  37
  38             /* The set *was* an intset and this value is not integer
  39              * encodable, so dictAdd should always work. */
  40             redisAssert(dictAdd(subject->ptr,value,NULL) == DICT_OK);
  41             incrRefCount(value);
  42             return 1;
  43         }
  44     } else {
  45         redisPanic("Unknown set encoding");
  46     }
  47     return 0;
  48 }
  49
  50 int setTypeRemove(robj *subject, robj *value) {
  51     long long llval;
  52     if (subject->encoding == REDIS_ENCODING_HT) {
  53         if (dictDelete(subject->ptr,value) == DICT_OK) {
  54             if (htNeedsResize(subject->ptr)) dictResize(subject->ptr);
  55             return 1;
  56         }
  57     } else if (subject->encoding == REDIS_ENCODING_INTSET) {
  58         if (isObjectRepresentableAsLongLong(value,&llval) == REDIS_OK) {
  59             uint8_t success;
  60             subject->ptr = intsetRemove(subject->ptr,llval,&success);
  61             if (success) return 1;
  62         }
  63     } else {
  64         redisPanic("Unknown set encoding");
  65     }
  66     return 0;
  67 }
  68
  69 int setTypeIsMember(robj *subject, robj *value) {
  70     long long llval;
  71     if (subject->encoding == REDIS_ENCODING_HT) {
  72         return dictFind((dict*)subject->ptr,value) != NULL;
  73     } else if (subject->encoding == REDIS_ENCODING_INTSET) {
  74         if (isObjectRepresentableAsLongLong(value,&llval) == REDIS_OK) {
  75             return intsetFind((intset*)subject->ptr,llval);
  76         }
  77     } else {
  78         redisPanic("Unknown set encoding");
  79     }
  80     return 0;
  81 }
  82
  83 setTypeIterator *setTypeInitIterator(robj *subject) {
  84     setTypeIterator *si = zmalloc(sizeof(setTypeIterator));
  85     si->subject = subject;
  86     si->encoding = subject->encoding;
  87     if (si->encoding == REDIS_ENCODING_HT) {
  88         si->di = dictGetIterator(subject->ptr);
  89     } else if (si->encoding == REDIS_ENCODING_INTSET) {
  90         si->ii = 0;
  91     } else {
  92         redisPanic("Unknown set encoding");
  93     }
  94     return si;
  95 }
  96
  97 void setTypeReleaseIterator(setTypeIterator *si) {
  98     if (si->encoding == REDIS_ENCODING_HT)
  99         dictReleaseIterator(si->di);
 100     zfree(si);
 101 }
 102
 103 /* Move to the next entry in the set. Returns the object at the current
 104  * position, or NULL when the end is reached. This object will have its
 105  * refcount incremented, so the caller needs to take care of this. */
 106 robj *setTypeNext(setTypeIterator *si) {
 107     robj *ret = NULL;
 108     if (si->encoding == REDIS_ENCODING_HT) {
 109         dictEntry *de = dictNext(si->di);
 110         if (de != NULL) {
 111             ret = dictGetEntryKey(de);
 112             incrRefCount(ret);
 113         }
 114     } else if (si->encoding == REDIS_ENCODING_INTSET) {
 115         int64_t llval;
 116         if (intsetGet(si->subject->ptr,si->ii++,&llval))
 117             ret = createStringObjectFromLongLong(llval);
 118     }
 119     return ret;
 120 }
 121
 122
 123 /* Return random element from set. The returned object will always have
 124  * an incremented refcount. */
 125 robj *setTypeRandomElement(robj *subject) {
 126     robj *ret = NULL;
 127     if (subject->encoding == REDIS_ENCODING_HT) {
 128         dictEntry *de = dictGetRandomKey(subject->ptr);
 129         ret = dictGetEntryKey(de);
 130         incrRefCount(ret);
 131     } else if (subject->encoding == REDIS_ENCODING_INTSET) {
 132         long long llval = intsetRandom(subject->ptr);
 133         ret = createStringObjectFromLongLong(llval);
 134     } else {
 135         redisPanic("Unknown set encoding");
 136     }
 137     return ret;
 138 }
 139
 140 unsigned long setTypeSize(robj *subject) {
 141     if (subject->encoding == REDIS_ENCODING_HT) {
 142         return dictSize((dict*)subject->ptr);
 143     } else if (subject->encoding == REDIS_ENCODING_INTSET) {
 144         return intsetLen((intset*)subject->ptr);
 145     } else {
 146         redisPanic("Unknown set encoding");
 147     }
 148 }
 149
 150 /* Convert the set to specified encoding. The resulting dict (when converting
 151  * to a hashtable) is presized to hold the number of elements in the original
 152  * set. */
 153 void setTypeConvert(robj *subject, int enc) {
 154     setTypeIterator *si;
 155     robj *element;
 156     redisAssert(subject->type == REDIS_SET);
 157
 158     if (enc == REDIS_ENCODING_HT) {
 159         dict *d = dictCreate(&setDictType,NULL);
 160         /* Presize the dict to avoid rehashing */
 161         dictExpand(d,intsetLen(subject->ptr));
 162
 163         /* setTypeGet returns a robj with incremented refcount */
 164         si = setTypeInitIterator(subject);
 165         while ((element = setTypeNext(si)) != NULL)
 166             redisAssert(dictAdd(d,element,NULL) == DICT_OK);
 167         setTypeReleaseIterator(si);
 168
 169         subject->encoding = REDIS_ENCODING_HT;
 170         zfree(subject->ptr);
 171         subject->ptr = d;
 172     } else {
 173         redisPanic("Unsupported set conversion");
 174     }
 175 }
 176
 177 void saddCommand(redisClient *c) {
 178     robj *set;
 179
 180     set = lookupKeyWrite(c->db,c->argv[1]);
 181     if (set == NULL) {
 182         set = setTypeCreate(c->argv[2]);
 183         dbAdd(c->db,c->argv[1],set);
 184     } else {
 185         if (set->type != REDIS_SET) {
 186             addReply(c,shared.wrongtypeerr);
 187             return;
 188         }
 189     }
 190     if (setTypeAdd(set,c->argv[2])) {
 191         touchWatchedKey(c->db,c->argv[1]);
 192         server.dirty++;
 193         addReply(c,shared.cone);
 194     } else {
 195         addReply(c,shared.czero);
 196     }
 197 }
 198
 199 void sremCommand(redisClient *c) {
 200     robj *set;
 201
 202     if ((set = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
 203         checkType(c,set,REDIS_SET)) return;
 204
 205     if (setTypeRemove(set,c->argv[2])) {
 206         if (setTypeSize(set) == 0) dbDelete(c->db,c->argv[1]);
 207         touchWatchedKey(c->db,c->argv[1]);
 208         server.dirty++;
 209         addReply(c,shared.cone);
 210     } else {
 211         addReply(c,shared.czero);
 212     }
 213 }
 214
 215 void smoveCommand(redisClient *c) {
 216     robj *srcset, *dstset, *ele;
 217     srcset = lookupKeyWrite(c->db,c->argv[1]);
 218     dstset = lookupKeyWrite(c->db,c->argv[2]);
 219     ele = c->argv[3];
 220
 221     /* If the source key does not exist return 0 */
 222     if (srcset == NULL) {
 223         addReply(c,shared.czero);
 224         return;
 225     }
 226
 227     /* If the source key has the wrong type, or the destination key
 228      * is set and has the wrong type, return with an error. */
 229     if (checkType(c,srcset,REDIS_SET) ||
 230         (dstset && checkType(c,dstset,REDIS_SET))) return;
 231
 232     /* If srcset and dstset are equal, SMOVE is a no-op */
 233     if (srcset == dstset) {
 234         addReply(c,shared.cone);
 235         return;
 236     }
 237
 238     /* If the element cannot be removed from the src set, return 0. */
 239     if (!setTypeRemove(srcset,ele)) {
 240         addReply(c,shared.czero);
 241         return;
 242     }
 243
 244     /* Remove the src set from the database when empty */
 245     if (setTypeSize(srcset) == 0) dbDelete(c->db,c->argv[1]);
 246     touchWatchedKey(c->db,c->argv[1]);
 247     touchWatchedKey(c->db,c->argv[2]);
 248     server.dirty++;
 249
 250     /* Create the destination set when it doesn't exist */
 251     if (!dstset) {
 252         dstset = setTypeCreate(ele);
 253         dbAdd(c->db,c->argv[2],dstset);
 254     }
 255
 256     /* An extra key has changed when ele was successfully added to dstset */
 257     if (setTypeAdd(dstset,ele)) server.dirty++;
 258     addReply(c,shared.cone);
 259 }
 260
 261 void sismemberCommand(redisClient *c) {
 262     robj *set;
 263
 264     if ((set = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
 265         checkType(c,set,REDIS_SET)) return;
 266
 267     if (setTypeIsMember(set,c->argv[2]))
 268         addReply(c,shared.cone);
 269     else
 270         addReply(c,shared.czero);
 271 }
 272
 273 void scardCommand(redisClient *c) {
 274     robj *o;
 275
 276     if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
 277         checkType(c,o,REDIS_SET)) return;
 278
 279     addReplyLongLong(c,setTypeSize(o));
 280 }
 281
 282 void spopCommand(redisClient *c) {
 283     robj *set, *ele;
 284
 285     if ((set = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
 286         checkType(c,set,REDIS_SET)) return;
 287
 288     ele = setTypeRandomElement(set);
 289     if (ele == NULL) {
 290         addReply(c,shared.nullbulk);
 291     } else {
 292         setTypeRemove(set,ele);
 293         addReplyBulk(c,ele);
 294         decrRefCount(ele);
 295         if (setTypeSize(set) == 0) dbDelete(c->db,c->argv[1]);
 296         touchWatchedKey(c->db,c->argv[1]);
 297         server.dirty++;
 298     }
 299 }
 300
 301 void srandmemberCommand(redisClient *c) {
 302     robj *set, *ele;
 303
 304     if ((set = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
 305         checkType(c,set,REDIS_SET)) return;
 306
 307     ele = setTypeRandomElement(set);
 308     if (ele == NULL) {
 309         addReply(c,shared.nullbulk);
 310     } else {
 311         addReplyBulk(c,ele);
 312         decrRefCount(ele);
 313     }
 314 }
 315
 316 int qsortCompareSetsByCardinality(const void *s1, const void *s2) {
 317     return setTypeSize(*(robj**)s1)-setTypeSize(*(robj**)s2);
 318 }
 319
 320 void sinterGenericCommand(redisClient *c, robj **setkeys, unsigned long setnum, robj *dstkey) {
 321     robj **sets = zmalloc(sizeof(robj*)*setnum);
 322     setTypeIterator *si;
 323     robj *ele, *dstset = NULL;
 324     void *replylen = NULL;
 325     unsigned long j, cardinality = 0;
 326
 327     for (j = 0; j < setnum; j++) {
 328         robj *setobj = dstkey ?
 329             lookupKeyWrite(c->db,setkeys[j]) :
 330             lookupKeyRead(c->db,setkeys[j]);
 331         if (!setobj) {
 332             zfree(sets);
 333             if (dstkey) {
 334                 if (dbDelete(c->db,dstkey)) {
 335                     touchWatchedKey(c->db,dstkey);
 336                     server.dirty++;
 337                 }
 338                 addReply(c,shared.czero);
 339             } else {
 340                 addReply(c,shared.emptymultibulk);
 341             }
 342             return;
 343         }
 344         if (checkType(c,setobj,REDIS_SET)) {
 345             zfree(sets);
 346             return;
 347         }
 348         sets[j] = setobj;
 349     }
 350     /* Sort sets from the smallest to largest, this will improve our
 351      * algorithm's performace */
 352     qsort(sets,setnum,sizeof(robj*),qsortCompareSetsByCardinality);
 353
 354     /* The first thing we should output is the total number of elements...
 355      * since this is a multi-bulk write, but at this stage we don't know
 356      * the intersection set size, so we use a trick, append an empty object
 357      * to the output list and save the pointer to later modify it with the
 358      * right length */
 359     if (!dstkey) {
 360         replylen = addDeferredMultiBulkLength(c);
 361     } else {
 362         /* If we have a target key where to store the resulting set
 363          * create this key with an empty set inside */
 364         dstset = createIntsetObject();
 365     }
 366
 367     /* Iterate all the elements of the first (smallest) set, and test
 368      * the element against all the other sets, if at least one set does
 369      * not include the element it is discarded */
 370     si = setTypeInitIterator(sets[0]);
 371     while((ele = setTypeNext(si)) != NULL) {
 372         for (j = 1; j < setnum; j++)
 373             if (!setTypeIsMember(sets[j],ele)) break;
 374
 375         /* Only take action when all sets contain the member */
 376         if (j == setnum) {
 377             if (!dstkey) {
 378                 addReplyBulk(c,ele);
 379                 cardinality++;
 380             } else {
 381                 setTypeAdd(dstset,ele);
 382             }
 383         }
 384         decrRefCount(ele);
 385     }
 386     setTypeReleaseIterator(si);
 387
 388     if (dstkey) {
 389         /* Store the resulting set into the target, if the intersection
 390          * is not an empty set. */
 391         dbDelete(c->db,dstkey);
 392         if (setTypeSize(dstset) > 0) {
 393             dbAdd(c->db,dstkey,dstset);
 394             addReplyLongLong(c,setTypeSize(dstset));
 395         } else {
 396             decrRefCount(dstset);
 397             addReply(c,shared.czero);
 398         }
 399         touchWatchedKey(c->db,dstkey);
 400         server.dirty++;
 401     } else {
 402         setDeferredMultiBulkLength(c,replylen,cardinality);
 403     }
 404     zfree(sets);
 405 }
 406
 407 void sinterCommand(redisClient *c) {
 408     sinterGenericCommand(c,c->argv+1,c->argc-1,NULL);
 409 }
 410
 411 void sinterstoreCommand(redisClient *c) {
 412     sinterGenericCommand(c,c->argv+2,c->argc-2,c->argv[1]);
 413 }
 414
 415 #define REDIS_OP_UNION 0
 416 #define REDIS_OP_DIFF 1
 417 #define REDIS_OP_INTER 2
 418
 419 void sunionDiffGenericCommand(redisClient *c, robj **setkeys, int setnum, robj *dstkey, int op) {
 420     robj **sets = zmalloc(sizeof(robj*)*setnum);
 421     setTypeIterator *si;
 422     robj *ele, *dstset = NULL;
 423     int j, cardinality = 0;
 424
 425     for (j = 0; j < setnum; j++) {
 426         robj *setobj = dstkey ?
 427             lookupKeyWrite(c->db,setkeys[j]) :
 428             lookupKeyRead(c->db,setkeys[j]);
 429         if (!setobj) {
 430             sets[j] = NULL;
 431             continue;
 432         }
 433         if (checkType(c,setobj,REDIS_SET)) {
 434             zfree(sets);
 435             return;
 436         }
 437         sets[j] = setobj;
 438     }
 439
 440     /* We need a temp set object to store our union. If the dstkey
 441      * is not NULL (that is, we are inside an SUNIONSTORE operation) then
 442      * this set object will be the resulting object to set into the target key*/
 443     dstset = createIntsetObject();
 444
 445     /* Iterate all the elements of all the sets, add every element a single
 446      * time to the result set */
 447     for (j = 0; j < setnum; j++) {
 448         if (op == REDIS_OP_DIFF && j == 0 && !sets[j]) break; /* result set is empty */
 449         if (!sets[j]) continue; /* non existing keys are like empty sets */
 450
 451         si = setTypeInitIterator(sets[j]);
 452         while((ele = setTypeNext(si)) != NULL) {
 453             if (op == REDIS_OP_UNION || j == 0) {
 454                 if (setTypeAdd(dstset,ele)) {
 455                     cardinality++;
 456                 }
 457             } else if (op == REDIS_OP_DIFF) {
 458                 if (setTypeRemove(dstset,ele)) {
 459                     cardinality--;
 460                 }
 461             }
 462             decrRefCount(ele);
 463         }
 464         setTypeReleaseIterator(si);
 465
 466         /* Exit when result set is empty. */
 467         if (op == REDIS_OP_DIFF && cardinality == 0) break;
 468     }
 469
 470     /* Output the content of the resulting set, if not in STORE mode */
 471     if (!dstkey) {
 472         addReplyMultiBulkLen(c,cardinality);
 473         si = setTypeInitIterator(dstset);
 474         while((ele = setTypeNext(si)) != NULL) {
 475             addReplyBulk(c,ele);
 476             decrRefCount(ele);
 477         }
 478         setTypeReleaseIterator(si);
 479         decrRefCount(dstset);
 480     } else {
 481         /* If we have a target key where to store the resulting set
 482          * create this key with the result set inside */
 483         dbDelete(c->db,dstkey);
 484         if (setTypeSize(dstset) > 0) {
 485             dbAdd(c->db,dstkey,dstset);
 486             addReplyLongLong(c,setTypeSize(dstset));
 487         } else {
 488             decrRefCount(dstset);
 489             addReply(c,shared.czero);
 490         }
 491         touchWatchedKey(c->db,dstkey);
 492         server.dirty++;
 493     }
 494     zfree(sets);
 495 }
 496
 497 void sunionCommand(redisClient *c) {
 498     sunionDiffGenericCommand(c,c->argv+1,c->argc-1,NULL,REDIS_OP_UNION);
 499 }
 500
 501 void sunionstoreCommand(redisClient *c) {
 502     sunionDiffGenericCommand(c,c->argv+2,c->argc-2,c->argv[1],REDIS_OP_UNION);
 503 }
 504
 505 void sdiffCommand(redisClient *c) {
 506     sunionDiffGenericCommand(c,c->argv+1,c->argc-1,NULL,REDIS_OP_DIFF);
 507 }
 508
 509 void sdiffstoreCommand(redisClient *c) {
 510     sunionDiffGenericCommand(c,c->argv+2,c->argc-2,c->argv[1],REDIS_OP_DIFF);
 511 }