src/object.c

   1 #include "redis.h"
   2 #include <pthread.h>
   3 #include <math.h>
   4
   5 robj *createObject(int type, void *ptr) {
   6     robj *o;
   7
   8     if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
   9     if (listLength(server.objfreelist)) {
  10         listNode *head = listFirst(server.objfreelist);
  11         o = listNodeValue(head);
  12         listDelNode(server.objfreelist,head);
  13         if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
  14     } else {
  15         if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
  16         o = zmalloc(sizeof(*o));
  17     }
  18     o->type = type;
  19     o->encoding = REDIS_ENCODING_RAW;
  20     o->ptr = ptr;
  21     o->refcount = 1;
  22     if (server.vm_enabled) {
  23         /* Note that this code may run in the context of an I/O thread
  24          * and accessing server.lruclock in theory is an error
  25          * (no locks). But in practice this is safe, and even if we read
  26          * garbage Redis will not fail. */
  27         o->lru = server.lruclock;
  28         o->storage = REDIS_VM_MEMORY;
  29     }
  30     return o;
  31 }
  32
  33 robj *createStringObject(char *ptr, size_t len) {
  34     return createObject(REDIS_STRING,sdsnewlen(ptr,len));
  35 }
  36
  37 robj *createStringObjectFromLongLong(long long value) {
  38     robj *o;
  39     if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
  40         pthread_equal(pthread_self(),server.mainthread)) {
  41         incrRefCount(shared.integers[value]);
  42         o = shared.integers[value];
  43     } else {
  44         if (value >= LONG_MIN && value <= LONG_MAX) {
  45             o = createObject(REDIS_STRING, NULL);
  46             o->encoding = REDIS_ENCODING_INT;
  47             o->ptr = (void*)((long)value);
  48         } else {
  49             o = createObject(REDIS_STRING,sdsfromlonglong(value));
  50         }
  51     }
  52     return o;
  53 }
  54
  55 robj *dupStringObject(robj *o) {
  56     redisAssert(o->encoding == REDIS_ENCODING_RAW);
  57     return createStringObject(o->ptr,sdslen(o->ptr));
  58 }
  59
  60 robj *createListObject(void) {
  61     list *l = listCreate();
  62     robj *o = createObject(REDIS_LIST,l);
  63     listSetFreeMethod(l,decrRefCount);
  64     o->encoding = REDIS_ENCODING_LINKEDLIST;
  65     return o;
  66 }
  67
  68 robj *createZiplistObject(void) {
  69     unsigned char *zl = ziplistNew();
  70     robj *o = createObject(REDIS_LIST,zl);
  71     o->encoding = REDIS_ENCODING_ZIPLIST;
  72     return o;
  73 }
  74
  75 robj *createSetObject(void) {
  76     dict *d = dictCreate(&setDictType,NULL);
  77     robj *o = createObject(REDIS_SET,d);
  78     o->encoding = REDIS_ENCODING_HT;
  79     return o;
  80 }
  81
  82 robj *createIntsetObject(void) {
  83     intset *is = intsetNew();
  84     robj *o = createObject(REDIS_SET,is);
  85     o->encoding = REDIS_ENCODING_INTSET;
  86     return o;
  87 }
  88
  89 robj *createHashObject(void) {
  90     /* All the Hashes start as zipmaps. Will be automatically converted
  91      * into hash tables if there are enough elements or big elements
  92      * inside. */
  93     unsigned char *zm = zipmapNew();
  94     robj *o = createObject(REDIS_HASH,zm);
  95     o->encoding = REDIS_ENCODING_ZIPMAP;
  96     return o;
  97 }
  98
  99 robj *createZsetObject(void) {
 100     zset *zs = zmalloc(sizeof(*zs));
 101
 102     zs->dict = dictCreate(&zsetDictType,NULL);
 103     zs->zsl = zslCreate();
 104     return createObject(REDIS_ZSET,zs);
 105 }
 106
 107 void freeStringObject(robj *o) {
 108     if (o->encoding == REDIS_ENCODING_RAW) {
 109         sdsfree(o->ptr);
 110     }
 111 }
 112
 113 void freeListObject(robj *o) {
 114     switch (o->encoding) {
 115     case REDIS_ENCODING_LINKEDLIST:
 116         listRelease((list*) o->ptr);
 117         break;
 118     case REDIS_ENCODING_ZIPLIST:
 119         zfree(o->ptr);
 120         break;
 121     default:
 122         redisPanic("Unknown list encoding type");
 123     }
 124 }
 125
 126 void freeSetObject(robj *o) {
 127     switch (o->encoding) {
 128     case REDIS_ENCODING_HT:
 129         dictRelease((dict*) o->ptr);
 130         break;
 131     case REDIS_ENCODING_INTSET:
 132         zfree(o->ptr);
 133         break;
 134     default:
 135         redisPanic("Unknown set encoding type");
 136     }
 137 }
 138
 139 void freeZsetObject(robj *o) {
 140     zset *zs = o->ptr;
 141
 142     dictRelease(zs->dict);
 143     zslFree(zs->zsl);
 144     zfree(zs);
 145 }
 146
 147 void freeHashObject(robj *o) {
 148     switch (o->encoding) {
 149     case REDIS_ENCODING_HT:
 150         dictRelease((dict*) o->ptr);
 151         break;
 152     case REDIS_ENCODING_ZIPMAP:
 153         zfree(o->ptr);
 154         break;
 155     default:
 156         redisPanic("Unknown hash encoding type");
 157         break;
 158     }
 159 }
 160
 161 void incrRefCount(robj *o) {
 162     o->refcount++;
 163 }
 164
 165 void decrRefCount(void *obj) {
 166     robj *o = obj;
 167
 168     /* Object is a swapped out value, or in the process of being loaded. */
 169     if (server.vm_enabled &&
 170         (o->storage == REDIS_VM_SWAPPED || o->storage == REDIS_VM_LOADING))
 171     {
 172         vmpointer *vp = obj;
 173         if (o->storage == REDIS_VM_LOADING) vmCancelThreadedIOJob(o);
 174         vmMarkPagesFree(vp->page,vp->usedpages);
 175         server.vm_stats_swapped_objects--;
 176         zfree(vp);
 177         return;
 178     }
 179
 180     if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
 181     /* Object is in memory, or in the process of being swapped out.
 182      *
 183      * If the object is being swapped out, abort the operation on
 184      * decrRefCount even if the refcount does not drop to 0: the object
 185      * is referenced at least two times, as value of the key AND as
 186      * job->val in the iojob. So if we don't invalidate the iojob, when it is
 187      * done but the relevant key was removed in the meantime, the
 188      * complete jobs handler will not find the key about the job and the
 189      * assert will fail. */
 190     if (server.vm_enabled && o->storage == REDIS_VM_SWAPPING)
 191         vmCancelThreadedIOJob(o);
 192     if (--(o->refcount) == 0) {
 193         switch(o->type) {
 194         case REDIS_STRING: freeStringObject(o); break;
 195         case REDIS_LIST: freeListObject(o); break;
 196         case REDIS_SET: freeSetObject(o); break;
 197         case REDIS_ZSET: freeZsetObject(o); break;
 198         case REDIS_HASH: freeHashObject(o); break;
 199         default: redisPanic("Unknown object type"); break;
 200         }
 201         o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
 202         if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
 203         if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX ||
 204             !listAddNodeHead(server.objfreelist,o))
 205             zfree(o);
 206         if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
 207     }
 208 }
 209
 210 int checkType(redisClient *c, robj *o, int type) {
 211     if (o->type != type) {
 212         addReply(c,shared.wrongtypeerr);
 213         return 1;
 214     }
 215     return 0;
 216 }
 217
 218 /* Try to encode a string object in order to save space */
 219 robj *tryObjectEncoding(robj *o) {
 220     long value;
 221     sds s = o->ptr;
 222
 223     if (o->encoding != REDIS_ENCODING_RAW)
 224         return o; /* Already encoded */
 225
 226     /* It's not safe to encode shared objects: shared objects can be shared
 227      * everywhere in the "object space" of Redis. Encoded objects can only
 228      * appear as "values" (and not, for instance, as keys) */
 229      if (o->refcount > 1) return o;
 230
 231     /* Currently we try to encode only strings */
 232     redisAssert(o->type == REDIS_STRING);
 233
 234     /* Check if we can represent this string as a long integer */
 235     if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
 236
 237     /* Ok, this object can be encoded...
 238      *
 239      * Can I use a shared object? Only if the object is inside a given
 240      * range and if this is the main thread, since when VM is enabled we
 241      * have the constraint that I/O thread should only handle non-shared
 242      * objects, in order to avoid race conditions (we don't have per-object
 243      * locking). */
 244     if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
 245         pthread_equal(pthread_self(),server.mainthread)) {
 246         decrRefCount(o);
 247         incrRefCount(shared.integers[value]);
 248         return shared.integers[value];
 249     } else {
 250         o->encoding = REDIS_ENCODING_INT;
 251         sdsfree(o->ptr);
 252         o->ptr = (void*) value;
 253         return o;
 254     }
 255 }
 256
 257 /* Get a decoded version of an encoded object (returned as a new object).
 258  * If the object is already raw-encoded just increment the ref count. */
 259 robj *getDecodedObject(robj *o) {
 260     robj *dec;
 261
 262     if (o->encoding == REDIS_ENCODING_RAW) {
 263         incrRefCount(o);
 264         return o;
 265     }
 266     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 267         char buf[32];
 268
 269         ll2string(buf,32,(long)o->ptr);
 270         dec = createStringObject(buf,strlen(buf));
 271         return dec;
 272     } else {
 273         redisPanic("Unknown encoding type");
 274     }
 275 }
 276
 277 /* Compare two string objects via strcmp() or alike.
 278  * Note that the objects may be integer-encoded. In such a case we
 279  * use ll2string() to get a string representation of the numbers on the stack
 280  * and compare the strings, it's much faster than calling getDecodedObject().
 281  *
 282  * Important note: if objects are not integer encoded, but binary-safe strings,
 283  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 284  * binary safe. */
 285 int compareStringObjects(robj *a, robj *b) {
 286     redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
 287     char bufa[128], bufb[128], *astr, *bstr;
 288     int bothsds = 1;
 289
 290     if (a == b) return 0;
 291     if (a->encoding != REDIS_ENCODING_RAW) {
 292         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 293         astr = bufa;
 294         bothsds = 0;
 295     } else {
 296         astr = a->ptr;
 297     }
 298     if (b->encoding != REDIS_ENCODING_RAW) {
 299         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 300         bstr = bufb;
 301         bothsds = 0;
 302     } else {
 303         bstr = b->ptr;
 304     }
 305     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 306 }
 307
 308 /* Equal string objects return 1 if the two objects are the same from the
 309  * point of view of a string comparison, otherwise 0 is returned. Note that
 310  * this function is faster then checking for (compareStringObject(a,b) == 0)
 311  * because it can perform some more optimization. */
 312 int equalStringObjects(robj *a, robj *b) {
 313     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 314         return a->ptr == b->ptr;
 315     } else {
 316         return compareStringObjects(a,b) == 0;
 317     }
 318 }
 319
 320 size_t stringObjectLen(robj *o) {
 321     redisAssert(o->type == REDIS_STRING);
 322     if (o->encoding == REDIS_ENCODING_RAW) {
 323         return sdslen(o->ptr);
 324     } else {
 325         char buf[32];
 326
 327         return ll2string(buf,32,(long)o->ptr);
 328     }
 329 }
 330
 331 int getDoubleFromObject(robj *o, double *target) {
 332     double value;
 333     char *eptr;
 334
 335     if (o == NULL) {
 336         value = 0;
 337     } else {
 338         redisAssert(o->type == REDIS_STRING);
 339         if (o->encoding == REDIS_ENCODING_RAW) {
 340             value = strtod(o->ptr, &eptr);
 341             if (eptr[0] != '\0' || isnan(value)) return REDIS_ERR;
 342         } else if (o->encoding == REDIS_ENCODING_INT) {
 343             value = (long)o->ptr;
 344         } else {
 345             redisPanic("Unknown string encoding");
 346         }
 347     }
 348
 349     *target = value;
 350     return REDIS_OK;
 351 }
 352
 353 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 354     double value;
 355     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 356         if (msg != NULL) {
 357             addReplyError(c,(char*)msg);
 358         } else {
 359             addReplyError(c,"value is not a double");
 360         }
 361         return REDIS_ERR;
 362     }
 363
 364     *target = value;
 365     return REDIS_OK;
 366 }
 367
 368 int getLongLongFromObject(robj *o, long long *target) {
 369     long long value;
 370     char *eptr;
 371
 372     if (o == NULL) {
 373         value = 0;
 374     } else {
 375         redisAssert(o->type == REDIS_STRING);
 376         if (o->encoding == REDIS_ENCODING_RAW) {
 377             value = strtoll(o->ptr, &eptr, 10);
 378             if (eptr[0] != '\0') return REDIS_ERR;
 379             if (errno == ERANGE && (value == LLONG_MIN || value == LLONG_MAX))
 380                 return REDIS_ERR;
 381         } else if (o->encoding == REDIS_ENCODING_INT) {
 382             value = (long)o->ptr;
 383         } else {
 384             redisPanic("Unknown string encoding");
 385         }
 386     }
 387
 388     if (target) *target = value;
 389     return REDIS_OK;
 390 }
 391
 392 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 393     long long value;
 394     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 395         if (msg != NULL) {
 396             addReplyError(c,(char*)msg);
 397         } else {
 398             addReplyError(c,"value is not an integer or out of range");
 399         }
 400         return REDIS_ERR;
 401     }
 402
 403     *target = value;
 404     return REDIS_OK;
 405 }
 406
 407 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 408     long long value;
 409
 410     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 411     if (value < LONG_MIN || value > LONG_MAX) {
 412         if (msg != NULL) {
 413             addReplyError(c,(char*)msg);
 414         } else {
 415             addReplyError(c,"value is out of range");
 416         }
 417         return REDIS_ERR;
 418     }
 419
 420     *target = value;
 421     return REDIS_OK;
 422 }
 423
 424 char *strEncoding(int encoding) {
 425     switch(encoding) {
 426     case REDIS_ENCODING_RAW: return "raw";
 427     case REDIS_ENCODING_INT: return "int";
 428     case REDIS_ENCODING_HT: return "hashtable";
 429     case REDIS_ENCODING_ZIPMAP: return "zipmap";
 430     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 431     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 432     case REDIS_ENCODING_INTSET: return "intset";
 433     default: return "unknown";
 434     }
 435 }