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     addReplyUlong(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, *lenobj = NULL, *dstset = NULL;
 324     unsigned long j, cardinality = 0;
 325
 326     for (j = 0; j < setnum; j++) {
 327         robj *setobj = dstkey ?
 328             lookupKeyWrite(c->db,setkeys[j]) :
 329             lookupKeyRead(c->db,setkeys[j]);
 330         if (!setobj) {
 331             zfree(sets);
 332             if (dstkey) {
 333                 if (dbDelete(c->db,dstkey)) {
 334                     touchWatchedKey(c->db,dstkey);
 335                     server.dirty++;
 336                 }
 337                 addReply(c,shared.czero);
 338             } else {
 339                 addReply(c,shared.emptymultibulk);
 340             }
 341             return;
 342         }
 343         if (checkType(c,setobj,REDIS_SET)) {
 344             zfree(sets);
 345             return;
 346         }
 347         sets[j] = setobj;
 348     }
 349     /* Sort sets from the smallest to largest, this will improve our
 350      * algorithm's performace */
 351     qsort(sets,setnum,sizeof(robj*),qsortCompareSetsByCardinality);
 352
 353     /* The first thing we should output is the total number of elements...
 354      * since this is a multi-bulk write, but at this stage we don't know
 355      * the intersection set size, so we use a trick, append an empty object
 356      * to the output list and save the pointer to later modify it with the
 357      * right length */
 358     if (!dstkey) {
 359         lenobj = createObject(REDIS_STRING,NULL);
 360         addReply(c,lenobj);
 361         decrRefCount(lenobj);
 362     } else {
 363         /* If we have a target key where to store the resulting set
 364          * create this key with an empty set inside */
 365         dstset = createIntsetObject();
 366     }
 367
 368     /* Iterate all the elements of the first (smallest) set, and test
 369      * the element against all the other sets, if at least one set does
 370      * not include the element it is discarded */
 371     si = setTypeInitIterator(sets[0]);
 372     while((ele = setTypeNext(si)) != NULL) {
 373         for (j = 1; j < setnum; j++)
 374             if (!setTypeIsMember(sets[j],ele)) break;
 375
 376         /* Only take action when all sets contain the member */
 377         if (j == setnum) {
 378             if (!dstkey) {
 379                 addReplyBulk(c,ele);
 380                 cardinality++;
 381             } else {
 382                 setTypeAdd(dstset,ele);
 383             }
 384         }
 385         decrRefCount(ele);
 386     }
 387     setTypeReleaseIterator(si);
 388
 389     if (dstkey) {
 390         /* Store the resulting set into the target, if the intersection
 391          * is not an empty set. */
 392         dbDelete(c->db,dstkey);
 393         if (setTypeSize(dstset) > 0) {
 394             dbAdd(c->db,dstkey,dstset);
 395             addReplyLongLong(c,setTypeSize(dstset));
 396         } else {
 397             decrRefCount(dstset);
 398             addReply(c,shared.czero);
 399         }
 400         touchWatchedKey(c->db,dstkey);
 401         server.dirty++;
 402     } else {
 403         lenobj->ptr = sdscatprintf(sdsempty(),"*%lu\r\n",cardinality);
 404     }
 405     zfree(sets);
 406 }
 407
 408 void sinterCommand(redisClient *c) {
 409     sinterGenericCommand(c,c->argv+1,c->argc-1,NULL);
 410 }
 411
 412 void sinterstoreCommand(redisClient *c) {
 413     sinterGenericCommand(c,c->argv+2,c->argc-2,c->argv[1]);
 414 }
 415
 416 #define REDIS_OP_UNION 0
 417 #define REDIS_OP_DIFF 1
 418 #define REDIS_OP_INTER 2
 419
 420 void sunionDiffGenericCommand(redisClient *c, robj **setkeys, int setnum, robj *dstkey, int op) {
 421     robj **sets = zmalloc(sizeof(robj*)*setnum);
 422     setTypeIterator *si;
 423     robj *ele, *dstset = NULL;
 424     int j, cardinality = 0;
 425
 426     for (j = 0; j < setnum; j++) {
 427         robj *setobj = dstkey ?
 428             lookupKeyWrite(c->db,setkeys[j]) :
 429             lookupKeyRead(c->db,setkeys[j]);
 430         if (!setobj) {
 431             sets[j] = NULL;
 432             continue;
 433         }
 434         if (checkType(c,setobj,REDIS_SET)) {
 435             zfree(sets);
 436             return;
 437         }
 438         sets[j] = setobj;
 439     }
 440
 441     /* We need a temp set object to store our union. If the dstkey
 442      * is not NULL (that is, we are inside an SUNIONSTORE operation) then
 443      * this set object will be the resulting object to set into the target key*/
 444     dstset = createIntsetObject();
 445
 446     /* Iterate all the elements of all the sets, add every element a single
 447      * time to the result set */
 448     for (j = 0; j < setnum; j++) {
 449         if (op == REDIS_OP_DIFF && j == 0 && !sets[j]) break; /* result set is empty */
 450         if (!sets[j]) continue; /* non existing keys are like empty sets */
 451
 452         si = setTypeInitIterator(sets[j]);
 453         while((ele = setTypeNext(si)) != NULL) {
 454             if (op == REDIS_OP_UNION || j == 0) {
 455                 if (setTypeAdd(dstset,ele)) {
 456                     cardinality++;
 457                 }
 458             } else if (op == REDIS_OP_DIFF) {
 459                 if (setTypeRemove(dstset,ele)) {
 460                     cardinality--;
 461                 }
 462             }
 463             decrRefCount(ele);
 464         }
 465         setTypeReleaseIterator(si);
 466
 467         /* Exit when result set is empty. */
 468         if (op == REDIS_OP_DIFF && cardinality == 0) break;
 469     }
 470
 471     /* Output the content of the resulting set, if not in STORE mode */
 472     if (!dstkey) {
 473         addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",cardinality));
 474         si = setTypeInitIterator(dstset);
 475         while((ele = setTypeNext(si)) != NULL) {
 476             addReplyBulk(c,ele);
 477             decrRefCount(ele);
 478         }
 479         setTypeReleaseIterator(si);
 480         decrRefCount(dstset);
 481     } else {
 482         /* If we have a target key where to store the resulting set
 483          * create this key with the result set inside */
 484         dbDelete(c->db,dstkey);
 485         if (setTypeSize(dstset) > 0) {
 486             dbAdd(c->db,dstkey,dstset);
 487             addReplyLongLong(c,setTypeSize(dstset));
 488         } else {
 489             decrRefCount(dstset);
 490             addReply(c,shared.czero);
 491         }
 492         touchWatchedKey(c->db,dstkey);
 493         server.dirty++;
 494     }
 495     zfree(sets);
 496 }
 497
 498 void sunionCommand(redisClient *c) {
 499     sunionDiffGenericCommand(c,c->argv+1,c->argc-1,NULL,REDIS_OP_UNION);
 500 }
 501
 502 void sunionstoreCommand(redisClient *c) {
 503     sunionDiffGenericCommand(c,c->argv+2,c->argc-2,c->argv[1],REDIS_OP_UNION);
 504 }
 505
 506 void sdiffCommand(redisClient *c) {
 507     sunionDiffGenericCommand(c,c->argv+1,c->argc-1,NULL,REDIS_OP_DIFF);
 508 }
 509
 510 void sdiffstoreCommand(redisClient *c) {
 511     sunionDiffGenericCommand(c,c->argv+2,c->argc-2,c->argv[1],REDIS_OP_DIFF);
 512 }