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