void decrRefCount(robj *o) {
if (o->refcount <= 0) serverPanic("decrRefCount against refcount <= 0");
if (o->refcount == 1) {
switch(o->type) {
case OBJ_STRING: freeStringObject(o); break;
default: serverPanic("Unknown object type"); break;
}
zfree(o);
} else {
o->refcount--;
}
}
/* Convert the set to specified encoding. The resulting dict (when converting
* to a hash table) is presized to hold the number of elements in the original
* set. */
void setTypeConvert(robj *setobj, int enc) {
setTypeIterator *si;
serverAssertWithInfo(NULL,setobj,setobj->type == OBJ_SET &&
setobj->encoding == OBJ_ENCODING_INTSET);
if (enc == OBJ_ENCODING_HT) {
int64_t intele;
dict *d = dictCreate(&setDictType,NULL);
sds element;
/* Presize the dict to avoid rehashing */
dictExpand(d,intsetLen(setobj->ptr));
/* To add the elements we extract integers and create redis objects */
si = setTypeInitIterator(setobj);
while (setTypeNext(si,&element,&intele) != -1) {
element = sdsfromlonglong(intele);
serverAssert(dictAdd(d,element,NULL) == DICT_OK);
}
setTypeReleaseIterator(si);
setobj->encoding = OBJ_ENCODING_HT;
zfree(setobj->ptr);
setobj->ptr = d;
} else {
serverPanic("Unsupported set conversion");
}
}
// LSET key index value
// LSET命令实现
void lsetCommand(client *c) {
//以写操作取出key对象的value值
robj *o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr);
// 如果key没找到或value对象不是列表类型则直接返回
if (o == NULL || checkType(c,o,OBJ_LIST)) return;
long index;
robj *value = c->argv[3];
//将index参数转换为long类型的整数，保存在index中
if ((getLongFromObjectOrReply(c, c->argv[2], &index, NULL) != C_OK))
return;
//只对编码为quicklist类型的value对象操作
if (o->encoding == OBJ_ENCODING_QUICKLIST) {
quicklist *ql = o->ptr;
//将下标为index的entry替换成value对象的值
int replaced = quicklistReplaceAtIndex(ql, index,
value->ptr, sdslen(value->ptr));
if (!replaced) {
//如果替换失败，则发送下标越界错误信息
addReply(c,shared.outofrangeerr);
} else {
//替换成功，则发送ok
addReply(c,shared.ok);
//当数据库的键被改动，则会调用该函数发送信号
signalModifiedKey(c->db,c->argv[1]);
//发送"lset"时间通知
notifyKeyspaceEvent(NOTIFY_LIST,"lset",c->argv[1],c->db->id);
//更新脏键
server.dirty++;
}
} else {
serverPanic("Unknown list encoding");
}
}
// LINDEX key index
// LINDEX命令的实现
void lindexCommand(client *c) {
//以读操作取出key对象的value值
robj *o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk);
//如果key没找到或value对象不是列表类型则直接返回
if (o == NULL || checkType(c,o,OBJ_LIST)) return;
long index;
robj *value = NULL;
//将index参数转换为long类型的整数，保存在index中
if ((getLongFromObjectOrReply(c, c->argv[2], &index, NULL) != C_OK))
return;
//只对编码为quicklist类型的value对象操作
if (o->encoding == OBJ_ENCODING_QUICKLIST) {
quicklistEntry entry;
//将下标为index的entry节点保存到entry中
if (quicklistIndex(o->ptr, index, &entry)) {
if (entry.value) { //如果vlaue是字符串类型
//创建一个字符串类型的对象，保存value值
value = createStringObject((char*)entry.value,entry.sz);
} else {
//将整型的value值转换为字符串类型并创建字符串类型的对象
value = createStringObjectFromLongLong(entry.longval);
}
addReplyBulk(c,value); //发送value对象
decrRefCount(value); //释放value对象
} else {
addReply(c,shared.nullbulk); //如果下标为index没找到，则发送空信息
}
} else {
serverPanic("Unknown list encoding"); //发送未知的列表编码类型
}
}
//从对象中将字符串值转换为long double并存储在target中
int getLongDoubleFromObject(robj *o, long double *target) {
long double value;
char *eptr;
if (o == NULL) { //对象不存在
value = 0;
} else {
serverAssertWithInfo(NULL,o,o->type == OBJ_STRING);
//如果是字符串编码的两种类型
if (sdsEncodedObject(o)) {
errno = 0;
value = strtold(o->ptr, &eptr); //将字符串转换为long double类型
if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' ||
errno == ERANGE || isnan(value)) //转换失败返回-1
return C_ERR;
} else if (o->encoding == OBJ_ENCODING_INT) { //整数编码
value = (long)o->ptr; //保存整数值
} else {
serverPanic("Unknown string encoding");
}
}
*target = value; //将值存到传入参数中，返回0成功
return C_OK;
}
void decrRefCount(robj *o) {
if (o->refcount <= 0) serverPanic("decrRefCount against refcount <= 0");
if (o->refcount == 1) {
switch(o->type) {
case OBJ_STRING: freeStringObject(o); break;
case OBJ_LIST: freeListObject(o); break;
case OBJ_SET: freeSetObject(o); break;
case OBJ_ZSET: freeZsetObject(o); break;
case OBJ_HASH: freeHashObject(o); break;
default: serverPanic("Unknown object type"); break;
}
dfree(o);
} else {
o->refcount--;
}
}
//初始化列表类型的迭代器为一个指定的下标
listTypeIterator *listTypeInitIterator(robj *subject, long index,
unsigned char direction) {
listTypeIterator *li = zmalloc(sizeof(listTypeIterator)); //分配空间
//设置迭代器的各个成员的初始值
li->subject = subject;
li->encoding = subject->encoding;
li->direction = direction;
li->iter = NULL; //quicklist迭代器为空
/* LIST_HEAD means start at TAIL and move *towards* head.
* LIST_TAIL means start at HEAD and move *towards tail. */
//获得迭代方向
int iter_direction =
direction == LIST_HEAD ? AL_START_TAIL : AL_START_HEAD;
//对列表对象编码为quicklist类型操作
if (li->encoding == OBJ_ENCODING_QUICKLIST) {
//将迭代器和下标为index的quicklistNode结合，迭代器指向该节点
li->iter = quicklistGetIteratorAtIdx(li->subject->ptr,
iter_direction, index);
} else {
serverPanic("Unknown list encoding");
}
return li;
}
unsigned long listTypeLength(robj *subject) {
if (subject->encoding == OBJ_ENCODING_QUICKLIST) {
return quicklistCount(subject->ptr);
} else {
serverPanic("Unknown list encoding");
}
}
void lsetCommand(client *c) {
robj *o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr);
if (o == NULL || checkType(c,o,OBJ_LIST)) return;
long index;
robj *value = c->argv[3];
if ((getLongFromObjectOrReply(c, c->argv[2], &index, NULL) != C_OK))
return;
if (o->encoding == OBJ_ENCODING_QUICKLIST) {
quicklist *ql = o->ptr;
int replaced = quicklistReplaceAtIndex(ql, index,
value->ptr, sdslen(value->ptr));
if (!replaced) {
addReply(c,shared.outofrangeerr);
} else {
addReply(c,shared.ok);
signalModifiedKey(c->db,c->argv[1]);
notifyKeyspaceEvent(NOTIFY_LIST,"lset",c->argv[1],c->db->id);
server.dirty++;
}
} else {
serverPanic("Unknown list encoding");
}
}
/* This callback is used by scanGenericCommand in order to collect elements
* returned by the dictionary iterator into a list. */
void scanCallback(void *privdata, const dictEntry *de) {
void **pd = (void**) privdata;
list *keys = pd[0];
robj *o = pd[1];
robj *key, *val = NULL;
if (o == NULL) {
sds sdskey = dictGetKey(de);
key = createStringObject(sdskey, sdslen(sdskey));
} else if (o->type == OBJ_SET) {
key = dictGetKey(de);
incrRefCount(key);
} else if (o->type == OBJ_HASH) {
key = dictGetKey(de);
incrRefCount(key);
val = dictGetVal(de);
incrRefCount(val);
} else if (o->type == OBJ_ZSET) {
key = dictGetKey(de);
incrRefCount(key);
val = createStringObjectFromLongDouble(*(double*)dictGetVal(de),0);
} else {
serverPanic("Type not handled in SCAN callback.");
}
listAddNodeTail(keys, key);
if (val) listAddNodeTail(keys, val);
}
void lindexCommand(client *c) {
robj *o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk);
if (o == NULL || checkType(c,o,OBJ_LIST)) return;
long index;
robj *value = NULL;
if ((getLongFromObjectOrReply(c, c->argv[2], &index, NULL) != C_OK))
return;
if (o->encoding == OBJ_ENCODING_QUICKLIST) {
quicklistEntry entry;
if (quicklistIndex(o->ptr, index, &entry)) {
if (entry.value) {
value = createStringObject((char*)entry.value,entry.sz);
} else {
value = createStringObjectFromLongLong(entry.longval);
}
addReplyBulk(c,value);
decrRefCount(value);
} else {
addReply(c,shared.nullbulk);
}
} else {
serverPanic("Unknown list encoding");
}
}
/* Delete the element pointed to. */
void listTypeDelete(listTypeIterator *iter, listTypeEntry *entry) {
if (entry->li->encoding == OBJ_ENCODING_QUICKLIST) {
quicklistDelEntry(iter->iter, &entry->entry);
} else {
serverPanic("Unknown list encoding");
}
}
void freeListObject(robj *o) {
if (o->encoding == OBJ_ENCODING_QUICKLIST) {
quicklistRelease(o->ptr);
} else {
serverPanic("Unknown list encoding type");
}
}
int getDoubleFromObject(robj *o, double *target) {
double value;
char *eptr;
if (o == NULL) {
value = 0;
} else {
serverAssertWithInfo(NULL,o,o->type == OBJ_STRING);
if (sdsEncodedObject(o)) {
errno = 0;
value = strtod(o->ptr, &eptr);
if (isspace(((char*)o->ptr)[0]) ||
eptr[0] != '\0' ||
(errno == ERANGE &&
(value == HUGE_VAL || value == -HUGE_VAL || value == 0)) ||
errno == EINVAL ||
isnan(value))
return C_ERR;
} else if (o->encoding == OBJ_ENCODING_INT) {
value = (long)o->ptr;
} else {
serverPanic("Unknown string encoding");
}
}
*target = value;
return C_OK;
}
/* Add the specified value into a set.
*
* If the value was already member of the set, nothing is done and 0 is
* returned, otherwise the new element is added and 1 is returned. */
int setTypeAdd(robj *subject, sds value) {
long long llval;
if (subject->encoding == OBJ_ENCODING_HT) {
dict *ht = subject->ptr;
dictEntry *de = dictAddRaw(ht,value);
if (de) {
dictSetKey(ht,de,sdsdup(value));
dictSetVal(ht,de,NULL);
return 1;
}
} else if (subject->encoding == OBJ_ENCODING_INTSET) {
if (isSdsRepresentableAsLongLong(value,&llval) == C_OK) {
uint8_t success = 0;
subject->ptr = intsetAdd(subject->ptr,llval,&success);
if (success) {
/* Convert to regular set when the intset contains
* too many entries. */
if (intsetLen(subject->ptr) > server.set_max_intset_entries)
setTypeConvert(subject,OBJ_ENCODING_HT);
return 1;
}
} else {
/* Failed to get integer from object, convert to regular set. */
setTypeConvert(subject,OBJ_ENCODING_HT);
/* The set *was* an intset and this value is not integer
* encodable, so dictAdd should always work. */
serverAssert(dictAdd(subject->ptr,sdsdup(value),NULL) == DICT_OK);
return 1;
}
} else {
serverPanic("Unknown set encoding");
}
return 0;
}
/* Populates the Redis Command Table starting from the hard coded list
* we have on top of redis.c file. */
void populateCommandTable(void) {
int j;
int numcommands = sizeof(redisCommandTable)/sizeof(struct redisCommand);
for (j = 0; j < numcommands; j++) {
struct redisCommand *c = redisCommandTable+j;
char *f = c->sflags;
int retval1;
while(*f != '\0') {
switch(*f) {
case 'w': c->flags |= CMD_WRITE; break;
case 'r': c->flags |= CMD_READONLY; break;
case 'm': c->flags |= CMD_DENYOOM; break;
case 'a': c->flags |= CMD_ADMIN; break;
case 'p': c->flags |= CMD_PUBSUB; break;
case 's': c->flags |= CMD_NOSCRIPT; break;
case 'R': c->flags |= CMD_RANDOM; break;
case 'S': c->flags |= CMD_SORT_FOR_SCRIPT; break;
case 'l': c->flags |= CMD_LOADING; break;
case 't': c->flags |= CMD_STALE; break;
case 'M': c->flags |= CMD_SKIP_MONITOR; break;
case 'k': c->flags |= CMD_ASKING; break;
case 'F': c->flags |= CMD_FAST; break;
default: serverPanic("Unsupported command flag"); break;
}
f++;
}
retval1 = dictAdd(server.commands, sdsnew(c->name), c);
ASSERT(retval1 == DICT_OK);
}
}
// LTRIM key start stop
// LTRIM命令实现
void ltrimCommand(client *c) {
robj *o;
long start, end, llen, ltrim, rtrim;
//将字符串类型起始地址start和结束地址end转换为long类型保存在start和end中
//如果任意失败，则直接返回
if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != C_OK) ||
(getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != C_OK)) return;
// 以读操作取出key大小的value值，如果value对象不是列表类型，直接返回
if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.ok)) == NULL ||
checkType(c,o,OBJ_LIST)) return;
//获取列表元素数量
llen = listTypeLength(o);
/* convert negative indexes */
// 将负数范围转换成合法范围
if (start < 0) start = llen+start;
if (end < 0) end = llen+end;
if (start < 0) start = 0;
/* Invariant: start >= 0, so this test will be true when end < 0.
* The range is empty when start > end or start >= length. */
//不合理的范围，移除所有的元素
if (start > end || start >= llen) {
/* Out of range start or start > end result in empty list */
ltrim = llen;
rtrim = 0;
} else {
if (end >= llen) end = llen-1; //end值不能超过元素个数
ltrim = start; //左边界
rtrim = llen-end-1; //右边界
}
/* Remove list elements to perform the trim */
//只对编码为quicklist类型的value对象操作
if (o->encoding == OBJ_ENCODING_QUICKLIST) {
quicklistDelRange(o->ptr,0,ltrim); //删除左边界以左的所有元素
quicklistDelRange(o->ptr,-rtrim,rtrim); //删除左边界以右的所有元素
} else {
serverPanic("Unknown list encoding");
}
//发送"ltrim"事件通知
notifyKeyspaceEvent(NOTIFY_LIST,"ltrim",c->argv[1],c->db->id);
//如果将所有元素全部删除完了
if (listTypeLength(o) == 0) {
//从数据库中删除该key
dbDelete(c->db,c->argv[1]);
//发送"del"时间通知
notifyKeyspaceEvent(NOTIFY_GENERIC,"del",c->argv[1],c->db->id);
}
//当数据库的键被改动，则会调用该函数发送信号
signalModifiedKey(c->db,c->argv[1]);
//更新脏键
server.dirty++;
//发送ok信息给client
addReply(c,shared.ok);
}
//返回对象的长度，entry节点个数
unsigned long listTypeLength(robj *subject) {
//对列表对象编码为quicklist类型操作
if (subject->encoding == OBJ_ENCODING_QUICKLIST) {
return quicklistCount(subject->ptr); //返回对象的entry节点个数
} else {
serverPanic("Unknown list encoding");
}
}
/* Compare the given object with the entry at the current position. */
int listTypeEqual(listTypeEntry *entry, robj *o) {
if (entry->li->encoding == OBJ_ENCODING_QUICKLIST) {
serverAssertWithInfo(NULL,o,sdsEncodedObject(o));
return quicklistCompare(entry->entry.zi,o->ptr,sdslen(o->ptr));
} else {
serverPanic("Unknown list encoding");
}
}
unsigned long setTypeSize(robj *subject) {
if (subject->encoding == OBJ_ENCODING_HT) {
return dictSize((dict*)subject->ptr);
} else if (subject->encoding == OBJ_ENCODING_INTSET) {
return intsetLen((intset*)subject->ptr);
} else {
serverPanic("Unknown set encoding");
}
}
void freeListObject(robj *o) {
switch (o->encoding) {
case OBJ_ENCODING_QUICKLIST:
quicklistRelease(o->ptr);
break;
default:
serverPanic("Unknown list encoding type");
}
}
//删除迭代器指向的entry
void listTypeDelete(listTypeIterator *iter, listTypeEntry *entry) {
//对列表对象编码为quicklist类型操作
if (entry->li->encoding == OBJ_ENCODING_QUICKLIST) {
//删除entry节点，更新迭代器
quicklistDelEntry(iter->iter, &entry->entry);
} else {
serverPanic("Unknown list encoding");
}
}
//引用计数减1
void decrRefCount(robj *o) {
if (o->refcount <= 0) serverPanic("decrRefCount against refcount <= 0");
//当引用对象等于1时，在操作引用计数减1，直接释放对象的ptr和对象空间
if (o->refcount == 1) {
switch(o->type) {
case OBJ_STRING: freeStringObject(o); break;
case OBJ_LIST: freeListObject(o); break;
case OBJ_SET: freeSetObject(o); break;
case OBJ_ZSET: freeZsetObject(o); break;
case OBJ_HASH: freeHashObject(o); break;
default: serverPanic("Unknown object type"); break;
}
zfree(o);
} else {
o->refcount--; //否则减1
}
}
/* This function gets called when a blocked client timed out in order to
* send it a reply of some kind. */
void replyToBlockedClientTimedOut(client *c) {
if (c->btype == BLOCKED_LIST) {
addReply(c,shared.nullmultibulk);
} else if (c->btype == BLOCKED_WAIT) {
addReplyLongLong(c,replicationCountAcksByOffset(c->bpop.reploffset));
} else {
serverPanic("Unknown btype in replyToBlockedClientTimedOut().");
}
}
/* The function pushes an element to the specified list object 'subject',
* at head or tail position as specified by 'where'.
*
* There is no need for the caller to increment the refcount of 'value' as
* the function takes care of it if needed. */
void listTypePush(robj *subject, robj *value, int where) {
if (subject->encoding == OBJ_ENCODING_QUICKLIST) {
int pos = (where == LIST_HEAD) ? QUICKLIST_HEAD : QUICKLIST_TAIL;
value = getDecodedObject(value);
size_t len = sdslen(value->ptr);
quicklistPush(subject->ptr, value->ptr, len, pos);
decrRefCount(value);
} else {
serverPanic("Unknown list encoding");
}
}
void *bioProcessBackgroundJobs(void *arg) {
struct bio_job *job;
unsigned long type = (unsigned long) arg;
sigset_t sigset;
/* Make the thread killable at any time, so that bioKillThreads()
* can work reliably. */
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
pthread_mutex_lock(&bio_mutex[type]);
/* Block SIGALRM so we are sure that only the main thread will
* receive the watchdog signal. */
sigemptyset(&sigset);
sigaddset(&sigset, SIGALRM);
if (pthread_sigmask(SIG_BLOCK, &sigset, NULL))
serverLog(LL_WARNING,
"Warning: can't mask SIGALRM in bio.c thread: %s", strerror(errno));
while(1) {
listNode *ln;
/* The loop always starts with the lock hold. */
if (listLength(bio_jobs[type]) == 0) {
pthread_cond_wait(&bio_newjob_cond[type],&bio_mutex[type]);
continue;
}
/* Pop the job from the queue. */
ln = listFirst(bio_jobs[type]);
job = ln->value;
/* It is now possible to unlock the background system as we know have
* a stand alone job structure to process.*/
pthread_mutex_unlock(&bio_mutex[type]);
/* Process the job accordingly to its type. */
if (type == BIO_CLOSE_FILE) {
close((long)job->arg1);
} else if (type == BIO_AOF_FSYNC) {
aof_fsync((long)job->arg1);
} else {
serverPanic("Wrong job type in bioProcessBackgroundJobs().");
}
zfree(job);
/* Unblock threads blocked on bioWaitStepOfType() if any. */
pthread_cond_broadcast(&bio_step_cond[type]);
/* Lock again before reiterating the loop, if there are no longer
* jobs to process we'll block again in pthread_cond_wait(). */
pthread_mutex_lock(&bio_mutex[type]);
listDelNode(bio_jobs[type],ln);
bio_pending[type]--;
}
}
/* Stores pointer to current the entry in the provided entry structure
* and advances the position of the iterator. Returns 1 when the current
* entry is in fact an entry, 0 otherwise. */
int listTypeNext(listTypeIterator *li, listTypeEntry *entry) {
/* Protect from converting when iterating */
serverAssert(li->subject->encoding == li->encoding);
entry->li = li;
if (li->encoding == OBJ_ENCODING_QUICKLIST) {
return quicklistNext(li->iter, &entry->entry);
} else {
serverPanic("Unknown list encoding");
}
return 0;
}
void freeSetObject(robj *o) {
switch (o->encoding) {
case OBJ_ENCODING_HT:
dictRelease((dict*) o->ptr);
break;
case OBJ_ENCODING_INTSET:
zfree(o->ptr);
break;
default:
serverPanic("Unknown set encoding type");
}
}
//比较列表类型的entry结构与对象的entry节点的值是否等，相等返回1
int listTypeEqual(listTypeEntry *entry, robj *o) {
//对列表对象编码为quicklist类型操作
if (entry->li->encoding == OBJ_ENCODING_QUICKLIST) {
//确保objptr的编码类型是简单动态字符串类型的RAW或EMBSTR
serverAssertWithInfo(NULL,o,sdsEncodedObject(o));
//比较listTypeEntry结构中的entry值和给定的对象的值
return quicklistCompare(entry->entry.zi,o->ptr,sdslen(o->ptr));
} else {
serverPanic("Unknown list encoding");
}
}
void freeHashObject(robj *o) {
switch (o->encoding) {
case OBJ_ENCODING_HT:
dictRelease((dict*) o->ptr);
break;
case OBJ_ENCODING_ZIPLIST:
zfree(o->ptr);
break;
default:
serverPanic("Unknown hash encoding type");
break;
}
}