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         case REDIS_REPLY_NODE: freeStringObject(o); break;
 200         default: redisPanic("Unknown object type"); break;
 201         }
 202         o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
 203         if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
 204         if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX ||
 205             !listAddNodeHead(server.objfreelist,o))
 206             zfree(o);
 207         if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
 208     }
 209 }
 210
 211 int checkType(redisClient *c, robj *o, int type) {
 212     if (o->type != type) {
 213         addReply(c,shared.wrongtypeerr);
 214         return 1;
 215     }
 216     return 0;
 217 }
 218
 219 /* Try to encode a string object in order to save space */
 220 robj *tryObjectEncoding(robj *o) {
 221     long value;
 222     sds s = o->ptr;
 223
 224     if (o->encoding != REDIS_ENCODING_RAW)
 225         return o; /* Already encoded */
 226
 227     /* It's not safe to encode shared objects: shared objects can be shared
 228      * everywhere in the "object space" of Redis. Encoded objects can only
 229      * appear as "values" (and not, for instance, as keys) */
 230      if (o->refcount > 1) return o;
 231
 232     /* Currently we try to encode only strings */
 233     redisAssert(o->type == REDIS_STRING);
 234
 235     /* Check if we can represent this string as a long integer */
 236     if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
 237
 238     /* Ok, this object can be encoded...
 239      *
 240      * Can I use a shared object? Only if the object is inside a given
 241      * range and if this is the main thread, since when VM is enabled we
 242      * have the constraint that I/O thread should only handle non-shared
 243      * objects, in order to avoid race conditions (we don't have per-object
 244      * locking). */
 245     if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
 246         pthread_equal(pthread_self(),server.mainthread)) {
 247         decrRefCount(o);
 248         incrRefCount(shared.integers[value]);
 249         return shared.integers[value];
 250     } else {
 251         o->encoding = REDIS_ENCODING_INT;
 252         sdsfree(o->ptr);
 253         o->ptr = (void*) value;
 254         return o;
 255     }
 256 }
 257
 258 /* Get a decoded version of an encoded object (returned as a new object).
 259  * If the object is already raw-encoded just increment the ref count. */
 260 robj *getDecodedObject(robj *o) {
 261     robj *dec;
 262
 263     if (o->encoding == REDIS_ENCODING_RAW) {
 264         incrRefCount(o);
 265         return o;
 266     }
 267     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 268         char buf[32];
 269
 270         ll2string(buf,32,(long)o->ptr);
 271         dec = createStringObject(buf,strlen(buf));
 272         return dec;
 273     } else {
 274         redisPanic("Unknown encoding type");
 275     }
 276 }
 277
 278 /* Compare two string objects via strcmp() or alike.
 279  * Note that the objects may be integer-encoded. In such a case we
 280  * use ll2string() to get a string representation of the numbers on the stack
 281  * and compare the strings, it's much faster than calling getDecodedObject().
 282  *
 283  * Important note: if objects are not integer encoded, but binary-safe strings,
 284  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 285  * binary safe. */
 286 int compareStringObjects(robj *a, robj *b) {
 287     redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
 288     char bufa[128], bufb[128], *astr, *bstr;
 289     int bothsds = 1;
 290
 291     if (a == b) return 0;
 292     if (a->encoding != REDIS_ENCODING_RAW) {
 293         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 294         astr = bufa;
 295         bothsds = 0;
 296     } else {
 297         astr = a->ptr;
 298     }
 299     if (b->encoding != REDIS_ENCODING_RAW) {
 300         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 301         bstr = bufb;
 302         bothsds = 0;
 303     } else {
 304         bstr = b->ptr;
 305     }
 306     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 307 }
 308
 309 /* Equal string objects return 1 if the two objects are the same from the
 310  * point of view of a string comparison, otherwise 0 is returned. Note that
 311  * this function is faster then checking for (compareStringObject(a,b) == 0)
 312  * because it can perform some more optimization. */
 313 int equalStringObjects(robj *a, robj *b) {
 314     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 315         return a->ptr == b->ptr;
 316     } else {
 317         return compareStringObjects(a,b) == 0;
 318     }
 319 }
 320
 321 size_t stringObjectLen(robj *o) {
 322     redisAssert(o->type == REDIS_STRING);
 323     if (o->encoding == REDIS_ENCODING_RAW) {
 324         return sdslen(o->ptr);
 325     } else {
 326         char buf[32];
 327
 328         return ll2string(buf,32,(long)o->ptr);
 329     }
 330 }
 331
 332 int getDoubleFromObject(robj *o, double *target) {
 333     double value;
 334     char *eptr;
 335
 336     if (o == NULL) {
 337         value = 0;
 338     } else {
 339         redisAssert(o->type == REDIS_STRING);
 340         if (o->encoding == REDIS_ENCODING_RAW) {
 341             value = strtod(o->ptr, &eptr);
 342             if (eptr[0] != '\0' || isnan(value)) return REDIS_ERR;
 343         } else if (o->encoding == REDIS_ENCODING_INT) {
 344             value = (long)o->ptr;
 345         } else {
 346             redisPanic("Unknown string encoding");
 347         }
 348     }
 349
 350     *target = value;
 351     return REDIS_OK;
 352 }
 353
 354 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 355     double value;
 356     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 357         if (msg != NULL) {
 358             addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
 359         } else {
 360             addReplySds(c, sdsnew("-ERR value is not a double\r\n"));
 361         }
 362         return REDIS_ERR;
 363     }
 364
 365     *target = value;
 366     return REDIS_OK;
 367 }
 368
 369 int getLongLongFromObject(robj *o, long long *target) {
 370     long long value;
 371     char *eptr;
 372
 373     if (o == NULL) {
 374         value = 0;
 375     } else {
 376         redisAssert(o->type == REDIS_STRING);
 377         if (o->encoding == REDIS_ENCODING_RAW) {
 378             value = strtoll(o->ptr, &eptr, 10);
 379             if (eptr[0] != '\0') return REDIS_ERR;
 380             if (errno == ERANGE && (value == LLONG_MIN || value == LLONG_MAX))
 381                 return REDIS_ERR;
 382         } else if (o->encoding == REDIS_ENCODING_INT) {
 383             value = (long)o->ptr;
 384         } else {
 385             redisPanic("Unknown string encoding");
 386         }
 387     }
 388
 389     if (target) *target = value;
 390     return REDIS_OK;
 391 }
 392
 393 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 394     long long value;
 395     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 396         if (msg != NULL) {
 397             addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
 398         } else {
 399             addReplySds(c, sdsnew("-ERR value is not an integer or out of range\r\n"));
 400         }
 401         return REDIS_ERR;
 402     }
 403
 404     *target = value;
 405     return REDIS_OK;
 406 }
 407
 408 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 409     long long value;
 410
 411     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 412     if (value < LONG_MIN || value > LONG_MAX) {
 413         if (msg != NULL) {
 414             addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
 415         } else {
 416             addReplySds(c, sdsnew("-ERR value is out of range\r\n"));
 417         }
 418         return REDIS_ERR;
 419     }
 420
 421     *target = value;
 422     return REDIS_OK;
 423 }
 424
 425 char *strEncoding(int encoding) {
 426     switch(encoding) {
 427     case REDIS_ENCODING_RAW: return "raw";
 428     case REDIS_ENCODING_INT: return "int";
 429     case REDIS_ENCODING_HT: return "hashtable";
 430     case REDIS_ENCODING_ZIPMAP: return "zipmap";
 431     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 432     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 433     case REDIS_ENCODING_INTSET: return "intset";
 434     default: return "unknown";
 435     }
 436 }