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implemented a different approach to IO scheduling, so object->storage is no longer...
[redis.git] / src / object.c
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e2641e09 1#include "redis.h"
2#include <pthread.h>
673e1fb7 3#include <math.h>
e2641e09 4
5robj *createObject(int type, void *ptr) {
a9b18e54 6 robj *o = zmalloc(sizeof(*o));
e2641e09 7 o->type = type;
8 o->encoding = REDIS_ENCODING_RAW;
9 o->ptr = ptr;
10 o->refcount = 1;
a9b18e54 11
ef59a8bc 12 /* Set the LRU to the current lruclock (minutes resolution).
13 * We do this regardless of the fact VM is active as LRU is also
14 * used for the maxmemory directive when Redis is used as cache.
15 *
16 * Note that this code may run in the context of an I/O thread
17 * and accessing server.lruclock in theory is an error
18 * (no locks). But in practice this is safe, and even if we read
19 * garbage Redis will not fail. */
20 o->lru = server.lruclock;
21 /* The following is only needed if VM is active, but since the conditional
22 * is probably more costly than initializing the field it's better to
23 * have every field properly initialized anyway. */
e2641e09 24 return o;
25}
26
27robj *createStringObject(char *ptr, size_t len) {
28 return createObject(REDIS_STRING,sdsnewlen(ptr,len));
29}
30
31robj *createStringObjectFromLongLong(long long value) {
32 robj *o;
e002ec68 33 if (value >= 0 && value < REDIS_SHARED_INTEGERS &&
98a9abb6 34 !server.ds_enabled &&
e002ec68 35 pthread_equal(pthread_self(),server.mainthread)) {
e2641e09 36 incrRefCount(shared.integers[value]);
37 o = shared.integers[value];
38 } else {
39 if (value >= LONG_MIN && value <= LONG_MAX) {
40 o = createObject(REDIS_STRING, NULL);
41 o->encoding = REDIS_ENCODING_INT;
42 o->ptr = (void*)((long)value);
43 } else {
44 o = createObject(REDIS_STRING,sdsfromlonglong(value));
45 }
46 }
47 return o;
48}
49
50robj *dupStringObject(robj *o) {
51 redisAssert(o->encoding == REDIS_ENCODING_RAW);
52 return createStringObject(o->ptr,sdslen(o->ptr));
53}
54
55robj *createListObject(void) {
56 list *l = listCreate();
57 robj *o = createObject(REDIS_LIST,l);
58 listSetFreeMethod(l,decrRefCount);
59 o->encoding = REDIS_ENCODING_LINKEDLIST;
60 return o;
61}
62
63robj *createZiplistObject(void) {
64 unsigned char *zl = ziplistNew();
65 robj *o = createObject(REDIS_LIST,zl);
66 o->encoding = REDIS_ENCODING_ZIPLIST;
67 return o;
68}
69
70robj *createSetObject(void) {
71 dict *d = dictCreate(&setDictType,NULL);
96ffb2fe
PN
72 robj *o = createObject(REDIS_SET,d);
73 o->encoding = REDIS_ENCODING_HT;
74 return o;
75}
76
77robj *createIntsetObject(void) {
78 intset *is = intsetNew();
79 robj *o = createObject(REDIS_SET,is);
80 o->encoding = REDIS_ENCODING_INTSET;
81 return o;
e2641e09 82}
83
84robj *createHashObject(void) {
85 /* All the Hashes start as zipmaps. Will be automatically converted
86 * into hash tables if there are enough elements or big elements
87 * inside. */
88 unsigned char *zm = zipmapNew();
89 robj *o = createObject(REDIS_HASH,zm);
90 o->encoding = REDIS_ENCODING_ZIPMAP;
91 return o;
92}
93
94robj *createZsetObject(void) {
95 zset *zs = zmalloc(sizeof(*zs));
96
97 zs->dict = dictCreate(&zsetDictType,NULL);
98 zs->zsl = zslCreate();
99 return createObject(REDIS_ZSET,zs);
100}
101
102void freeStringObject(robj *o) {
103 if (o->encoding == REDIS_ENCODING_RAW) {
104 sdsfree(o->ptr);
105 }
106}
107
108void freeListObject(robj *o) {
109 switch (o->encoding) {
110 case REDIS_ENCODING_LINKEDLIST:
111 listRelease((list*) o->ptr);
112 break;
113 case REDIS_ENCODING_ZIPLIST:
114 zfree(o->ptr);
115 break;
116 default:
117 redisPanic("Unknown list encoding type");
118 }
119}
120
121void freeSetObject(robj *o) {
96ffb2fe
PN
122 switch (o->encoding) {
123 case REDIS_ENCODING_HT:
124 dictRelease((dict*) o->ptr);
125 break;
126 case REDIS_ENCODING_INTSET:
127 zfree(o->ptr);
128 break;
129 default:
130 redisPanic("Unknown set encoding type");
131 }
e2641e09 132}
133
134void freeZsetObject(robj *o) {
135 zset *zs = o->ptr;
136
137 dictRelease(zs->dict);
138 zslFree(zs->zsl);
139 zfree(zs);
140}
141
142void freeHashObject(robj *o) {
143 switch (o->encoding) {
144 case REDIS_ENCODING_HT:
145 dictRelease((dict*) o->ptr);
146 break;
147 case REDIS_ENCODING_ZIPMAP:
148 zfree(o->ptr);
149 break;
150 default:
151 redisPanic("Unknown hash encoding type");
152 break;
153 }
154}
155
156void incrRefCount(robj *o) {
157 o->refcount++;
158}
159
160void decrRefCount(void *obj) {
161 robj *o = obj;
162
e2641e09 163 if (o->refcount <= 0) redisPanic("decrRefCount against refcount <= 0");
e2641e09 164 if (--(o->refcount) == 0) {
165 switch(o->type) {
166 case REDIS_STRING: freeStringObject(o); break;
167 case REDIS_LIST: freeListObject(o); break;
168 case REDIS_SET: freeSetObject(o); break;
169 case REDIS_ZSET: freeZsetObject(o); break;
170 case REDIS_HASH: freeHashObject(o); break;
171 default: redisPanic("Unknown object type"); break;
172 }
2f996f02 173 o->ptr = NULL; /* defensive programming. We'll see NULL in traces. */
a9b18e54 174 zfree(o);
e2641e09 175 }
176}
177
178int checkType(redisClient *c, robj *o, int type) {
179 if (o->type != type) {
180 addReply(c,shared.wrongtypeerr);
181 return 1;
182 }
183 return 0;
184}
185
186/* Try to encode a string object in order to save space */
187robj *tryObjectEncoding(robj *o) {
188 long value;
189 sds s = o->ptr;
190
191 if (o->encoding != REDIS_ENCODING_RAW)
192 return o; /* Already encoded */
193
194 /* It's not safe to encode shared objects: shared objects can be shared
195 * everywhere in the "object space" of Redis. Encoded objects can only
196 * appear as "values" (and not, for instance, as keys) */
197 if (o->refcount > 1) return o;
198
199 /* Currently we try to encode only strings */
200 redisAssert(o->type == REDIS_STRING);
201
202 /* Check if we can represent this string as a long integer */
203 if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;
204
0e5441d8 205 /* Ok, this object can be encoded...
206 *
207 * Can I use a shared object? Only if the object is inside a given
cea8c5cd 208 * range and if the back end in use is in-memory. For disk store every
209 * object in memory used as value should be independent.
13a49af4 210 *
211 * Note that we also avoid using shared integers when maxmemory is used
cea8c5cd 212 * because every object needs to have a private LRU field for the LRU
13a49af4 213 * algorithm to work well. */
98a9abb6 214 if (!server.ds_enabled &&
cea8c5cd 215 server.maxmemory == 0 && value >= 0 && value < REDIS_SHARED_INTEGERS &&
216 pthread_equal(pthread_self(),server.mainthread))
217 {
e2641e09 218 decrRefCount(o);
219 incrRefCount(shared.integers[value]);
220 return shared.integers[value];
221 } else {
222 o->encoding = REDIS_ENCODING_INT;
223 sdsfree(o->ptr);
224 o->ptr = (void*) value;
225 return o;
226 }
227}
228
229/* Get a decoded version of an encoded object (returned as a new object).
230 * If the object is already raw-encoded just increment the ref count. */
231robj *getDecodedObject(robj *o) {
232 robj *dec;
233
234 if (o->encoding == REDIS_ENCODING_RAW) {
235 incrRefCount(o);
236 return o;
237 }
238 if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_INT) {
239 char buf[32];
240
241 ll2string(buf,32,(long)o->ptr);
242 dec = createStringObject(buf,strlen(buf));
243 return dec;
244 } else {
245 redisPanic("Unknown encoding type");
246 }
247}
248
249/* Compare two string objects via strcmp() or alike.
250 * Note that the objects may be integer-encoded. In such a case we
251 * use ll2string() to get a string representation of the numbers on the stack
252 * and compare the strings, it's much faster than calling getDecodedObject().
253 *
254 * Important note: if objects are not integer encoded, but binary-safe strings,
255 * sdscmp() from sds.c will apply memcmp() so this function ca be considered
256 * binary safe. */
257int compareStringObjects(robj *a, robj *b) {
258 redisAssert(a->type == REDIS_STRING && b->type == REDIS_STRING);
259 char bufa[128], bufb[128], *astr, *bstr;
260 int bothsds = 1;
261
262 if (a == b) return 0;
263 if (a->encoding != REDIS_ENCODING_RAW) {
264 ll2string(bufa,sizeof(bufa),(long) a->ptr);
265 astr = bufa;
266 bothsds = 0;
267 } else {
268 astr = a->ptr;
269 }
270 if (b->encoding != REDIS_ENCODING_RAW) {
271 ll2string(bufb,sizeof(bufb),(long) b->ptr);
272 bstr = bufb;
273 bothsds = 0;
274 } else {
275 bstr = b->ptr;
276 }
277 return bothsds ? sdscmp(astr,bstr) : strcmp(astr,bstr);
278}
279
280/* Equal string objects return 1 if the two objects are the same from the
281 * point of view of a string comparison, otherwise 0 is returned. Note that
282 * this function is faster then checking for (compareStringObject(a,b) == 0)
283 * because it can perform some more optimization. */
284int equalStringObjects(robj *a, robj *b) {
285 if (a->encoding != REDIS_ENCODING_RAW && b->encoding != REDIS_ENCODING_RAW){
286 return a->ptr == b->ptr;
287 } else {
288 return compareStringObjects(a,b) == 0;
289 }
290}
291
292size_t stringObjectLen(robj *o) {
293 redisAssert(o->type == REDIS_STRING);
294 if (o->encoding == REDIS_ENCODING_RAW) {
295 return sdslen(o->ptr);
296 } else {
297 char buf[32];
298
299 return ll2string(buf,32,(long)o->ptr);
300 }
301}
302
303int getDoubleFromObject(robj *o, double *target) {
304 double value;
305 char *eptr;
306
307 if (o == NULL) {
308 value = 0;
309 } else {
310 redisAssert(o->type == REDIS_STRING);
311 if (o->encoding == REDIS_ENCODING_RAW) {
312 value = strtod(o->ptr, &eptr);
673e1fb7 313 if (eptr[0] != '\0' || isnan(value)) return REDIS_ERR;
e2641e09 314 } else if (o->encoding == REDIS_ENCODING_INT) {
315 value = (long)o->ptr;
316 } else {
317 redisPanic("Unknown string encoding");
318 }
319 }
320
321 *target = value;
322 return REDIS_OK;
323}
324
325int getDoubleFromObjectOrReply(redisClient *c, robj *o, double *target, const char *msg) {
326 double value;
327 if (getDoubleFromObject(o, &value) != REDIS_OK) {
328 if (msg != NULL) {
3ab20376 329 addReplyError(c,(char*)msg);
e2641e09 330 } else {
3ab20376 331 addReplyError(c,"value is not a double");
e2641e09 332 }
333 return REDIS_ERR;
334 }
335
336 *target = value;
337 return REDIS_OK;
338}
339
340int getLongLongFromObject(robj *o, long long *target) {
341 long long value;
342 char *eptr;
343
344 if (o == NULL) {
345 value = 0;
346 } else {
347 redisAssert(o->type == REDIS_STRING);
348 if (o->encoding == REDIS_ENCODING_RAW) {
349 value = strtoll(o->ptr, &eptr, 10);
350 if (eptr[0] != '\0') return REDIS_ERR;
c91abdcd 351 if (errno == ERANGE && (value == LLONG_MIN || value == LLONG_MAX))
352 return REDIS_ERR;
e2641e09 353 } else if (o->encoding == REDIS_ENCODING_INT) {
354 value = (long)o->ptr;
355 } else {
356 redisPanic("Unknown string encoding");
357 }
358 }
359
96ffb2fe 360 if (target) *target = value;
e2641e09 361 return REDIS_OK;
362}
363
364int getLongLongFromObjectOrReply(redisClient *c, robj *o, long long *target, const char *msg) {
365 long long value;
366 if (getLongLongFromObject(o, &value) != REDIS_OK) {
367 if (msg != NULL) {
3ab20376 368 addReplyError(c,(char*)msg);
e2641e09 369 } else {
3ab20376 370 addReplyError(c,"value is not an integer or out of range");
e2641e09 371 }
372 return REDIS_ERR;
373 }
374
375 *target = value;
376 return REDIS_OK;
377}
378
379int getLongFromObjectOrReply(redisClient *c, robj *o, long *target, const char *msg) {
380 long long value;
381
382 if (getLongLongFromObjectOrReply(c, o, &value, msg) != REDIS_OK) return REDIS_ERR;
383 if (value < LONG_MIN || value > LONG_MAX) {
384 if (msg != NULL) {
3ab20376 385 addReplyError(c,(char*)msg);
e2641e09 386 } else {
3ab20376 387 addReplyError(c,"value is out of range");
e2641e09 388 }
389 return REDIS_ERR;
390 }
391
392 *target = value;
393 return REDIS_OK;
394}
395
396char *strEncoding(int encoding) {
397 switch(encoding) {
398 case REDIS_ENCODING_RAW: return "raw";
399 case REDIS_ENCODING_INT: return "int";
400 case REDIS_ENCODING_HT: return "hashtable";
401 case REDIS_ENCODING_ZIPMAP: return "zipmap";
402 case REDIS_ENCODING_LINKEDLIST: return "linkedlist";
403 case REDIS_ENCODING_ZIPLIST: return "ziplist";
96ffb2fe 404 case REDIS_ENCODING_INTSET: return "intset";
e2641e09 405 default: return "unknown";
406 }
407}
ef59a8bc 408
409/* Given an object returns the min number of seconds the object was never
410 * requested, using an approximated LRU algorithm. */
411unsigned long estimateObjectIdleTime(robj *o) {
412 if (server.lruclock >= o->lru) {
165346ca 413 return (server.lruclock - o->lru) * REDIS_LRU_CLOCK_RESOLUTION;
ef59a8bc 414 } else {
165346ca 415 return ((REDIS_LRU_CLOCK_MAX - o->lru) + server.lruclock) *
416 REDIS_LRU_CLOCK_RESOLUTION;
ef59a8bc 417 }
418}