src/object.c

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