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     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         if (server.vm_enabled) pthread_mutex_lock(&server.obj_freelist_mutex);
 183         if (listLength(server.objfreelist) > REDIS_OBJFREELIST_MAX ||
 184             !listAddNodeHead(server.objfreelist,o))
 185             zfree(o);
 186         if (server.vm_enabled) pthread_mutex_unlock(&server.obj_freelist_mutex);
 187     }
 188 }
 189
 190 int checkType(redisClient *c, robj *o, int type) {
 191     if (o->type != type) {
 192         addReply(c,shared.wrongtypeerr);
 193         return 1;
 194     }
 195     return 0;
 196 }
 197
 198 /* Try to encode a string object in order to save space */
 199 robj *tryObjectEncoding(robj *o) {
 200     long value;
 201     sds s = o->ptr;
 202
 203     if (o->encoding != REDIS_ENCODING_RAW)
 204         return o; /* Already encoded */
 205
 206     /* It's not safe to encode shared objects: shared objects can be shared
 207      * everywhere in the "object space" of Redis. Encoded objects can only
 208      * appear as "values" (and not, for instance, as keys) */
 209      if (o->refcount > 1) return o;
 210
 211     /* Currently we try to encode only strings */
 212     redisAssert(o->type == REDIS_STRING);
 213
 214     /* Check if we can represent this string as a long integer */
 215     if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
 216
 217     /* Ok, this object can be encoded */
 218     if (value >= 0 && value < REDIS_SHARED_INTEGERS) {
 219         decrRefCount(o);
 220         incrRefCount(shared.integers[value]);
 221         return shared.integers[value];
 222     } else {
 223         o->encoding = REDIS_ENCODING_INT;
 224         sdsfree(o->ptr);
 225         o->ptr = (void*) value;
 226         return o;
 227     }
 228 }
 229
 230 /* Get a decoded version of an encoded object (returned as a new object).
 231  * If the object is already raw-encoded just increment the ref count. */
 232 robj *getDecodedObject(robj *o) {
 233     robj *dec;
 234
 235     if (o->encoding == REDIS_ENCODING_RAW) {
 236         incrRefCount(o);
 237         return o;
 238     }
 239     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
 240         char buf[32];
 241
 242         ll2string(buf,32,(long)o->ptr);
 243         dec = createStringObject(buf,strlen(buf));
 244         return dec;
 245     } else {
 246         redisPanic("Unknown encoding type");
 247     }
 248 }
 249
 250 /* Compare two string objects via strcmp() or alike.
 251  * Note that the objects may be integer-encoded. In such a case we
 252  * use ll2string() to get a string representation of the numbers on the stack
 253  * and compare the strings, it's much faster than calling getDecodedObject().
 254  *
 255  * Important note: if objects are not integer encoded, but binary-safe strings,
 256  * sdscmp() from sds.c will apply memcmp() so this function ca be considered
 257  * binary safe. */
 258 int compareStringObjects(robj *a, robj *b) {
 259     redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
 260     char bufa[128], bufb[128], *astr, *bstr;
 261     int bothsds = 1;
 262
 263     if (a == b) return 0;
 264     if (a->encoding != REDIS_ENCODING_RAW) {
 265         ll2string(bufa,sizeof(bufa),(long) a->ptr);
 266         astr = bufa;
 267         bothsds = 0;
 268     } else {
 269         astr = a->ptr;
 270     }
 271     if (b->encoding != REDIS_ENCODING_RAW) {
 272         ll2string(bufb,sizeof(bufb),(long) b->ptr);
 273         bstr = bufb;
 274         bothsds = 0;
 275     } else {
 276         bstr = b->ptr;
 277     }
 278     return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
 279 }
 280
 281 /* Equal string objects return 1 if the two objects are the same from the
 282  * point of view of a string comparison, otherwise 0 is returned. Note that
 283  * this function is faster then checking for (compareStringObject(a,b) == 0)
 284  * because it can perform some more optimization. */
 285 int equalStringObjects(robj *a, robj *b) {
 286     if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
 287         return a->ptr == b->ptr;
 288     } else {
 289         return compareStringObjects(a,b) == 0;
 290     }
 291 }
 292
 293 size_t stringObjectLen(robj *o) {
 294     redisAssert(o->type == REDIS_STRING);
 295     if (o->encoding == REDIS_ENCODING_RAW) {
 296         return sdslen(o->ptr);
 297     } else {
 298         char buf[32];
 299
 300         return ll2string(buf,32,(long)o->ptr);
 301     }
 302 }
 303
 304 int getDoubleFromObject(robj *o, double *target) {
 305     double value;
 306     char *eptr;
 307
 308     if (o == NULL) {
 309         value = 0;
 310     } else {
 311         redisAssert(o->type == REDIS_STRING);
 312         if (o->encoding == REDIS_ENCODING_RAW) {
 313             value = strtod(o->ptr, &eptr);
 314             if (eptr[0] != '\0') return REDIS_ERR;
 315         } else if (o->encoding == REDIS_ENCODING_INT) {
 316             value = (long)o->ptr;
 317         } else {
 318             redisPanic("Unknown string encoding");
 319         }
 320     }
 321
 322     *target = value;
 323     return REDIS_OK;
 324 }
 325
 326 int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
 327     double value;
 328     if (getDoubleFromObject(o, &value) != REDIS_OK) {
 329         if (msg != NULL) {
 330             addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
 331         } else {
 332             addReplySds(c, sdsnew("-ERR value is not a double\r\n"));
 333         }
 334         return REDIS_ERR;
 335     }
 336
 337     *target = value;
 338     return REDIS_OK;
 339 }
 340
 341 int getLongLongFromObject(robj *o, long long *target) {
 342     long long value;
 343     char *eptr;
 344
 345     if (o == NULL) {
 346         value = 0;
 347     } else {
 348         redisAssert(o->type == REDIS_STRING);
 349         if (o->encoding == REDIS_ENCODING_RAW) {
 350             value = strtoll(o->ptr, &eptr, 10);
 351             if (eptr[0] != '\0') return REDIS_ERR;
 352         } else if (o->encoding == REDIS_ENCODING_INT) {
 353             value = (long)o->ptr;
 354         } else {
 355             redisPanic("Unknown string encoding");
 356         }
 357     }
 358
 359     *target = value;
 360     return REDIS_OK;
 361 }
 362
 363 int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
 364     long long value;
 365     if (getLongLongFromObject(o, &value) != REDIS_OK) {
 366         if (msg != NULL) {
 367             addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
 368         } else {
 369             addReplySds(c, sdsnew("-ERR value is not an integer\r\n"));
 370         }
 371         return REDIS_ERR;
 372     }
 373
 374     *target = value;
 375     return REDIS_OK;
 376 }
 377
 378 int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
 379     long long value;
 380
 381     if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
 382     if (value < LONG_MIN || value > LONG_MAX) {
 383         if (msg != NULL) {
 384             addReplySds(c, sdscatprintf(sdsempty(), "-ERR %s\r\n", msg));
 385         } else {
 386             addReplySds(c, sdsnew("-ERR value is out of range\r\n"));
 387         }
 388         return REDIS_ERR;
 389     }
 390
 391     *target = value;
 392     return REDIS_OK;
 393 }
 394
 395 char *strEncoding(int encoding) {
 396     switch(encoding) {
 397     case REDIS_ENCODING_RAW: return "raw";
 398     case REDIS_ENCODING_INT: return "int";
 399     case REDIS_ENCODING_HT: return "hashtable";
 400     case REDIS_ENCODING_ZIPMAP: return "zipmap";
 401     case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
 402     case REDIS_ENCODING_ZIPLIST: return "ziplist";
 403     default: return "unknown";
 404     }
 405 }