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