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 (getLongLongFromObject(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 (getLongLongFromObject(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 (getLongLongFromObject(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 (getLongLongFromObject(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 setIterator *setTypeInitIterator(robj *subject) {
  84     setIterator *si = zmalloc(sizeof(setIterator));
  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(setIterator *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(setIterator *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         long long 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     setIterator *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         server.dirty++;
 192         addReply(c,shared.cone);
 193     } else {
 194         addReply(c,shared.czero);
 195     }
 196 }
 197
 198 void sremCommand(redisClient *c) {
 199     robj *set;
 200
 201     if ((set = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
 202         checkType(c,set,REDIS_SET)) return;
 203
 204     if (setTypeRemove(set,c->argv[2])) {
 205         if (setTypeSize(set) == 0) dbDelete(c->db,c->argv[1]);
 206         server.dirty++;
 207         addReply(c,shared.cone);
 208     } else {
 209         addReply(c,shared.czero);
 210     }
 211 }
 212
 213 void smoveCommand(redisClient *c) {
 214     robj *srcset, *dstset, *ele;
 215     srcset = lookupKeyWrite(c->db,c->argv[1]);
 216     dstset = lookupKeyWrite(c->db,c->argv[2]);
 217     ele = c->argv[3];
 218
 219     /* If the source key does not exist return 0 */
 220     if (srcset == NULL) {
 221         addReply(c,shared.czero);
 222         return;
 223     }
 224
 225     /* If the source key has the wrong type, or the destination key
 226      * is set and has the wrong type, return with an error. */
 227     if (checkType(c,srcset,REDIS_SET) ||
 228         (dstset && checkType(c,dstset,REDIS_SET))) return;
 229
 230     /* If srcset and dstset are equal, SMOVE is a no-op */
 231     if (srcset == dstset) {
 232         addReply(c,shared.cone);
 233         return;
 234     }
 235
 236     /* If the element cannot be removed from the src set, return 0. */
 237     if (!setTypeRemove(srcset,ele)) {
 238         addReply(c,shared.czero);
 239         return;
 240     }
 241
 242     /* Remove the src set from the database when empty */
 243     if (setTypeSize(srcset) == 0) dbDelete(c->db,c->argv[1]);
 244     server.dirty++;
 245
 246     /* Create the destination set when it doesn't exist */
 247     if (!dstset) {
 248         dstset = setTypeCreate(ele);
 249         dbAdd(c->db,c->argv[2],dstset);
 250     }
 251
 252     /* An extra key has changed when ele was successfully added to dstset */
 253     if (setTypeAdd(dstset,ele)) server.dirty++;
 254     addReply(c,shared.cone);
 255 }
 256
 257 void sismemberCommand(redisClient *c) {
 258     robj *set;
 259
 260     if ((set = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
 261         checkType(c,set,REDIS_SET)) return;
 262
 263     if (setTypeIsMember(set,c->argv[2]))
 264         addReply(c,shared.cone);
 265     else
 266         addReply(c,shared.czero);
 267 }
 268
 269 void scardCommand(redisClient *c) {
 270     robj *o;
 271
 272     if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL ||
 273         checkType(c,o,REDIS_SET)) return;
 274
 275     addReplyUlong(c,setTypeSize(o));
 276 }
 277
 278 void spopCommand(redisClient *c) {
 279     robj *set, *ele;
 280
 281     if ((set = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
 282         checkType(c,set,REDIS_SET)) return;
 283
 284     ele = setTypeRandomElement(set);
 285     if (ele == NULL) {
 286         addReply(c,shared.nullbulk);
 287     } else {
 288         setTypeRemove(set,ele);
 289         addReplyBulk(c,ele);
 290         decrRefCount(ele);
 291         if (setTypeSize(set) == 0) dbDelete(c->db,c->argv[1]);
 292         server.dirty++;
 293     }
 294 }
 295
 296 void srandmemberCommand(redisClient *c) {
 297     robj *set, *ele;
 298
 299     if ((set = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
 300         checkType(c,set,REDIS_SET)) return;
 301
 302     ele = setTypeRandomElement(set);
 303     if (ele == NULL) {
 304         addReply(c,shared.nullbulk);
 305     } else {
 306         addReplyBulk(c,ele);
 307         decrRefCount(ele);
 308     }
 309 }
 310
 311 int qsortCompareSetsByCardinality(const void *s1, const void *s2) {
 312     return setTypeSize(*(robj**)s1)-setTypeSize(*(robj**)s2);
 313 }
 314
 315 void sinterGenericCommand(redisClient *c, robj **setkeys, unsigned long setnum, robj *dstkey) {
 316     robj **sets = zmalloc(sizeof(robj*)*setnum);
 317     setIterator *si;
 318     robj *ele, *lenobj = NULL, *dstset = NULL;
 319     unsigned long j, cardinality = 0;
 320
 321     for (j = 0; j < setnum; j++) {
 322         robj *setobj = dstkey ?
 323             lookupKeyWrite(c->db,setkeys[j]) :
 324             lookupKeyRead(c->db,setkeys[j]);
 325         if (!setobj) {
 326             zfree(sets);
 327             if (dstkey) {
 328                 if (dbDelete(c->db,dstkey))
 329                     server.dirty++;
 330                 addReply(c,shared.czero);
 331             } else {
 332                 addReply(c,shared.emptymultibulk);
 333             }
 334             return;
 335         }
 336         if (checkType(c,setobj,REDIS_SET)) {
 337             zfree(sets);
 338             return;
 339         }
 340         sets[j] = setobj;
 341     }
 342     /* Sort sets from the smallest to largest, this will improve our
 343      * algorithm's performace */
 344     qsort(sets,setnum,sizeof(robj*),qsortCompareSetsByCardinality);
 345
 346     /* The first thing we should output is the total number of elements...
 347      * since this is a multi-bulk write, but at this stage we don't know
 348      * the intersection set size, so we use a trick, append an empty object
 349      * to the output list and save the pointer to later modify it with the
 350      * right length */
 351     if (!dstkey) {
 352         lenobj = createObject(REDIS_STRING,NULL);
 353         addReply(c,lenobj);
 354         decrRefCount(lenobj);
 355     } else {
 356         /* If we have a target key where to store the resulting set
 357          * create this key with an empty set inside */
 358         dstset = createIntsetObject();
 359     }
 360
 361     /* Iterate all the elements of the first (smallest) set, and test
 362      * the element against all the other sets, if at least one set does
 363      * not include the element it is discarded */
 364     si = setTypeInitIterator(sets[0]);
 365     while((ele = setTypeNext(si)) != NULL) {
 366         for (j = 1; j < setnum; j++)
 367             if (!setTypeIsMember(sets[j],ele)) break;
 368
 369         /* Only take action when all sets contain the member */
 370         if (j == setnum) {
 371             if (!dstkey) {
 372                 addReplyBulk(c,ele);
 373                 cardinality++;
 374             } else {
 375                 setTypeAdd(dstset,ele);
 376             }
 377         }
 378         decrRefCount(ele);
 379     }
 380     setTypeReleaseIterator(si);
 381
 382     if (dstkey) {
 383         /* Store the resulting set into the target, if the intersection
 384          * is not an empty set. */
 385         dbDelete(c->db,dstkey);
 386         if (setTypeSize(dstset) > 0) {
 387             dbAdd(c->db,dstkey,dstset);
 388             addReplyLongLong(c,setTypeSize(dstset));
 389         } else {
 390             decrRefCount(dstset);
 391             addReply(c,shared.czero);
 392         }
 393         server.dirty++;
 394     } else {
 395         lenobj->ptr = sdscatprintf(sdsempty(),"*%lu\r\n",cardinality);
 396     }
 397     zfree(sets);
 398 }
 399
 400 void sinterCommand(redisClient *c) {
 401     sinterGenericCommand(c,c->argv+1,c->argc-1,NULL);
 402 }
 403
 404 void sinterstoreCommand(redisClient *c) {
 405     sinterGenericCommand(c,c->argv+2,c->argc-2,c->argv[1]);
 406 }
 407
 408 #define REDIS_OP_UNION 0
 409 #define REDIS_OP_DIFF 1
 410 #define REDIS_OP_INTER 2
 411
 412 void sunionDiffGenericCommand(redisClient *c, robj **setkeys, int setnum, robj *dstkey, int op) {
 413     robj **sets = zmalloc(sizeof(robj*)*setnum);
 414     setIterator *si;
 415     robj *ele, *dstset = NULL;
 416     int j, cardinality = 0;
 417
 418     for (j = 0; j < setnum; j++) {
 419         robj *setobj = dstkey ?
 420             lookupKeyWrite(c->db,setkeys[j]) :
 421             lookupKeyRead(c->db,setkeys[j]);
 422         if (!setobj) {
 423             sets[j] = NULL;
 424             continue;
 425         }
 426         if (checkType(c,setobj,REDIS_SET)) {
 427             zfree(sets);
 428             return;
 429         }
 430         sets[j] = setobj;
 431     }
 432
 433     /* We need a temp set object to store our union. If the dstkey
 434      * is not NULL (that is, we are inside an SUNIONSTORE operation) then
 435      * this set object will be the resulting object to set into the target key*/
 436     dstset = createIntsetObject();
 437
 438     /* Iterate all the elements of all the sets, add every element a single
 439      * time to the result set */
 440     for (j = 0; j < setnum; j++) {
 441         if (op == REDIS_OP_DIFF && j == 0 && !sets[j]) break; /* result set is empty */
 442         if (!sets[j]) continue; /* non existing keys are like empty sets */
 443
 444         si = setTypeInitIterator(sets[j]);
 445         while((ele = setTypeNext(si)) != NULL) {
 446             if (op == REDIS_OP_UNION || j == 0) {
 447                 if (setTypeAdd(dstset,ele)) {
 448                     cardinality++;
 449                 }
 450             } else if (op == REDIS_OP_DIFF) {
 451                 if (setTypeRemove(dstset,ele)) {
 452                     cardinality--;
 453                 }
 454             }
 455             decrRefCount(ele);
 456         }
 457         setTypeReleaseIterator(si);
 458
 459         /* Exit when result set is empty. */
 460         if (op == REDIS_OP_DIFF && cardinality == 0) break;
 461     }
 462
 463     /* Output the content of the resulting set, if not in STORE mode */
 464     if (!dstkey) {
 465         addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",cardinality));
 466         si = setTypeInitIterator(dstset);
 467         while((ele = setTypeNext(si)) != NULL) {
 468             addReplyBulk(c,ele);
 469             decrRefCount(ele);
 470         }
 471         setTypeReleaseIterator(si);
 472         decrRefCount(dstset);
 473     } else {
 474         /* If we have a target key where to store the resulting set
 475          * create this key with the result set inside */
 476         dbDelete(c->db,dstkey);
 477         if (setTypeSize(dstset) > 0) {
 478             dbAdd(c->db,dstkey,dstset);
 479             addReplyLongLong(c,setTypeSize(dstset));
 480         } else {
 481             decrRefCount(dstset);
 482             addReply(c,shared.czero);
 483         }
 484         server.dirty++;
 485     }
 486     zfree(sets);
 487 }
 488
 489 void sunionCommand(redisClient *c) {
 490     sunionDiffGenericCommand(c,c->argv+1,c->argc-1,NULL,REDIS_OP_UNION);
 491 }
 492
 493 void sunionstoreCommand(redisClient *c) {
 494     sunionDiffGenericCommand(c,c->argv+2,c->argc-2,c->argv[1],REDIS_OP_UNION);
 495 }
 496
 497 void sdiffCommand(redisClient *c) {
 498     sunionDiffGenericCommand(c,c->argv+1,c->argc-1,NULL,REDIS_OP_DIFF);
 499 }
 500
 501 void sdiffstoreCommand(redisClient *c) {
 502     sunionDiffGenericCommand(c,c->argv+2,c->argc-2,c->argv[1],REDIS_OP_DIFF);
 503 }