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