void complete_nread(conn *c) {
item *it = c->item;
int comm = c->item_comm;
item *old_it;
time_t now = time(0);
stats.set_cmds++;
while(1) {
if (strncmp(ITEM_data(it) + it->nbytes - 2, "\r\n", 2) != 0) {
out_string(c, "CLIENT_ERROR bad data chunk");
break;
}
old_it = assoc_find(ITEM_key(it));
if (old_it && settings.oldest_live &&
old_it->time <= settings.oldest_live) {
item_unlink(old_it);
old_it = 0;
}
if (old_it && old_it->exptime && old_it->exptime < now) {
item_unlink(old_it);
old_it = 0;
}
if (old_it && comm==NREAD_ADD) {
item_update(old_it);
out_string(c, "NOT_STORED");
break;
}
if (!old_it && comm == NREAD_REPLACE) {
out_string(c, "NOT_STORED");
break;
}
if (old_it && (old_it->it_flags & ITEM_DELETED) && (comm == NREAD_REPLACE || comm == NREAD_ADD)) {
out_string(c, "NOT_STORED");
break;
}
if (old_it) {
item_replace(old_it, it);
} else item_link(it);
c->item = 0;
out_string(c, "STORED");
return;
}
item_free(it);
c->item = 0;
return;
}
enum store_item_type do_store_item ( item *it, int comm, const uint32_t hv )
{
char *key = ITEM_key (it);
item *old_it = do_item_get (key, it->nkey, hv);
enum store_item_type stored = NOT_STORED;
item *new_it = NULL;
int flags;
if ( old_it != NULL && comm == NREAD_ADD )
{
do_item_update (old_it);
}
else if ( ! old_it && ( comm == NREAD_REPLACE || comm == NREAD_APPEND || comm == NREAD_PREPEND ) )
{
}
else
{
if ( comm == NREAD_APPEND || comm == NREAD_PREPEND )
{
if ( stored == NOT_STORED )
{
flags = ( int ) strtol (ITEM_suffix (old_it), ( char ** ) NULL, 10);
new_it = do_item_alloc (key, it->nkey, flags, old_it->exptime, ITEM_data (it), it->nbytes + old_it->nbytes - 2, hv);
if ( ! new_it )
{
if ( old_it )
do_item_remove (old_it);
return NOT_STORED;
}
if ( comm == NREAD_APPEND )
{
memcpy (ITEM_data (new_it), ITEM_data (old_it), old_it->nbytes);
memcpy (ITEM_data (new_it) + old_it->nbytes - 2, ITEM_data (it), it->nbytes);
}
else
{
memcpy (ITEM_data (new_it), ITEM_data (it), it->nbytes);
memcpy (ITEM_data (new_it) + it->nbytes - 2, ITEM_data (old_it), old_it->nbytes);
}
it = new_it;
}
}
if ( stored == NOT_STORED )
{
if ( old_it != NULL )
{
item_replace (old_it, it, hv);
}
else
{
do_item_link (it, hv);
}
stored = STORED;
}
}
if ( old_it != NULL )
{
do_item_remove (old_it);
}
if ( new_it != NULL )
{
do_item_remove (new_it);
}
return stored;
}
int LRU_list::do_store_item(base_item* it, Conn* c, uint32_t hv) {
char* key = it->data;
//获取旧的数据项
base_item* old_it = do_item_get(key, it->nkey, hv);
int store_stat = LRU_list::NOT_STORED;
base_item* new_it = 0;
int flags = 0;
//已经有该项item存在
if (old_it != 0 && c->cmd == NREAD_ADD) {
/*
* 更新当前item目的
* 1.更新时间,重建LRU链
* 2.后面执行do_item_remove，每次remove会把refcount引用计数减一
* 如果引用计数=1则被删除，重建之后refcount为2
* */
do_item_update(old_it);
//旧的item不存在
}else if (!old_it && (c->cmd == NREAD_REPLACE || c->cmd == NREAD_APPEND
|| c->cmd == NREAD_PREPEND)) {
//什么也不做,因为只有replace替换已有值
}else if (c->cmd == NREAD_CAS) {
//不存在此项
if (old_it == 0) {
store_stat = LRU_list::NOT_FOUND;
}
if (it->cas == old_it->cas) {
item_replace(old_it, it, hv);
store_stat = LRU_list::STORED;
}
else {
if (mem_setting.verbose > 1) {
std::cerr << "CAS: failure: expected " << old_it->get_cas() << " but got "
<< it->cas;
}
store_stat = LRU_list::EXISTS;
}
}
else {
//与上面第二个判断不同，这里是旧的item存在的replace append prepend set命令
if (c->cmd == NREAD_APPEND || c->cmd == NREAD_PREPEND) {
//if (it->cas != 0) {
if (it->cas != old_it->cas) {
store_stat = LRU_list::EXISTS;
}
//}
if (store_stat == LRU_list::NOT_STORED) {
new_it = do_item_alloc(key, it->nkey, flags, old_it->exptime,
it->nbytes + old_it->nbytes - 2, hv);
//分配失败
if (new_it == 0) {
if (old_it != 0)
do_item_remove(old_it);
return LRU_list::NOT_STORED;
}
new_it->nkey = old_it->nkey;
new_it->item_flag = flags;
new_it->exptime = old_it->exptime;
new_it->nbytes = it->nbytes + old_it->nbytes - 2;
memcpy(new_it->data, old_it->data, old_it->nkey);
new_it->data[old_it->nkey] = '0';
//copy数据
if (c->cmd == NREAD_APPEND) {
memcpy(new_it->real_data_addr(), old_it->real_data_addr(),
old_it->nbytes);
memcpy(new_it->real_data_addr() + old_it->nbytes - 2/*\r\n*/,
it->real_data_addr(), it->nbytes);
}
else {
//NREAD_PREPEND
memcpy(new_it->real_data_addr(), it->real_data_addr(), it->nbytes);
memcpy(new_it->real_data_addr() + it->nbytes - 2,
old_it->real_data_addr(), old_it->nbytes);
}
it = new_it;
}
}
if (store_stat == LRU_list::NOT_STORED) {
it->cas++;
if (old_it != 0)
item_replace(old_it, it, hv);
else
//set a new key-value
do_item_link(it, hv);
store_stat = LRU_list::STORED;
}
}
if (old_it != 0)
do_item_remove(old_it);
if (new_it != 0)
do_item_remove(new_it);
if (store_stat == LRU_list::STORED) {
c->cas = it->get_cas();
}
return store_stat;
}
static int storage_write(void *storage, const int clsid, const int item_age) {
int did_moves = 0;
struct lru_pull_tail_return it_info;
it_info.it = NULL;
lru_pull_tail(clsid, COLD_LRU, 0, LRU_PULL_RETURN_ITEM, 0, &it_info);
/* Item is locked, and we have a reference to it. */
if (it_info.it == NULL) {
return did_moves;
}
obj_io io;
item *it = it_info.it;
/* First, storage for the header object */
size_t orig_ntotal = ITEM_ntotal(it);
uint32_t flags;
if ((it->it_flags & ITEM_HDR) == 0 &&
(item_age == 0 || current_time - it->time > item_age)) {
FLAGS_CONV(it, flags);
item *hdr_it = do_item_alloc(ITEM_key(it), it->nkey, flags, it->exptime, sizeof(item_hdr));
/* Run the storage write understanding the start of the item is dirty.
* We will fill it (time/exptime/etc) from the header item on read.
*/
if (hdr_it != NULL) {
int bucket = (it->it_flags & ITEM_CHUNKED) ?
PAGE_BUCKET_CHUNKED : PAGE_BUCKET_DEFAULT;
// Compress soon to expire items into similar pages.
if (it->exptime - current_time < settings.ext_low_ttl) {
bucket = PAGE_BUCKET_LOWTTL;
}
hdr_it->it_flags |= ITEM_HDR;
io.len = orig_ntotal;
io.mode = OBJ_IO_WRITE;
// NOTE: when the item is read back in, the slab mover
// may see it. Important to have refcount>=2 or ~ITEM_LINKED
assert(it->refcount >= 2);
// NOTE: write bucket vs free page bucket will disambiguate once
// lowttl feature is better understood.
if (extstore_write_request(storage, bucket, bucket, &io) == 0) {
// cuddle the hash value into the time field so we don't have
// to recalculate it.
item *buf_it = (item *) io.buf;
buf_it->time = it_info.hv;
// copy from past the headers + time headers.
// TODO: should be in items.c
if (it->it_flags & ITEM_CHUNKED) {
// Need to loop through the item and copy
item_chunk *sch = (item_chunk *) ITEM_schunk(it);
int remain = orig_ntotal;
int copied = 0;
// copy original header
int hdrtotal = ITEM_ntotal(it) - it->nbytes;
memcpy((char *)io.buf+STORE_OFFSET, (char *)it+STORE_OFFSET, hdrtotal - STORE_OFFSET);
copied = hdrtotal;
// copy data in like it were one large object.
while (sch && remain) {
assert(remain >= sch->used);
memcpy((char *)io.buf+copied, sch->data, sch->used);
// FIXME: use one variable?
remain -= sch->used;
copied += sch->used;
sch = sch->next;
}
} else {
memcpy((char *)io.buf+STORE_OFFSET, (char *)it+STORE_OFFSET, io.len-STORE_OFFSET);
}
// crc what we copied so we can do it sequentially.
buf_it->it_flags &= ~ITEM_LINKED;
buf_it->exptime = crc32c(0, (char*)io.buf+STORE_OFFSET, orig_ntotal-STORE_OFFSET);
extstore_write(storage, &io);
item_hdr *hdr = (item_hdr *) ITEM_data(hdr_it);
hdr->page_version = io.page_version;
hdr->page_id = io.page_id;
hdr->offset = io.offset;
// overload nbytes for the header it
hdr_it->nbytes = it->nbytes;
/* success! Now we need to fill relevant data into the new
* header and replace. Most of this requires the item lock
*/
/* CAS gets set while linking. Copy post-replace */
item_replace(it, hdr_it, it_info.hv);
ITEM_set_cas(hdr_it, ITEM_get_cas(it));
do_item_remove(hdr_it);
did_moves = 1;
LOGGER_LOG(NULL, LOG_EVICTIONS, LOGGER_EXTSTORE_WRITE, it, bucket);
} else {
/* Failed to write for some reason, can't continue. */
slabs_free(hdr_it, ITEM_ntotal(hdr_it), ITEM_clsid(hdr_it));
}
}
}
do_item_remove(it);
item_unlock(it_info.hv);
return did_moves;
}
void process_command(conn *c, char *command) {
int comm = 0;
int incr = 0;
/*
* for commands set/add/replace, we build an item and read the data
* directly into it, then continue in nread_complete().
*/
if (settings.verbose > 1)
fprintf(stderr, "<%d %s\n", c->sfd, command);
/* All incoming commands will require a response, so we cork at the beginning,
and uncork at the very end (usually by means of out_string) */
set_cork(c, 1);
if ((strncmp(command, "add ", 4) == 0 && (comm = NREAD_ADD)) ||
(strncmp(command, "set ", 4) == 0 && (comm = NREAD_SET)) ||
(strncmp(command, "replace ", 8) == 0 && (comm = NREAD_REPLACE))) {
char key[251];
int flags;
time_t expire;
int len, res;
item *it;
res = sscanf(command, "%*s %250s %u %ld %d\n", key, &flags, &expire, &len);
if (res!=4 || strlen(key)==0 ) {
out_string(c, "CLIENT_ERROR bad command line format");
return;
}
expire = realtime(expire);
it = item_alloc(key, flags, expire, len+2);
if (it == 0) {
out_string(c, "SERVER_ERROR out of memory");
/* swallow the data line */
c->write_and_go = conn_swallow;
c->sbytes = len+2;
return;
}
c->item_comm = comm;
c->item = it;
c->rcurr = ITEM_data(it);
c->rlbytes = it->nbytes;
c->state = conn_nread;
return;
}
if ((strncmp(command, "incr ", 5) == 0 && (incr = 1)) ||
(strncmp(command, "decr ", 5) == 0)) {
char temp[32];
unsigned int value;
item *it;
unsigned int delta;
char key[251];
int res;
char *ptr;
time_t now = time(0);
res = sscanf(command, "%*s %250s %u\n", key, &delta);
if (res!=2 || strlen(key)==0 ) {
out_string(c, "CLIENT_ERROR bad command line format");
return;
}
it = assoc_find(key);
if (it && (it->it_flags & ITEM_DELETED)) {
it = 0;
}
if (it && it->exptime && it->exptime < now) {
item_unlink(it);
it = 0;
}
if (!it) {
out_string(c, "NOT_FOUND");
return;
}
ptr = ITEM_data(it);
while (*ptr && (*ptr<'0' && *ptr>'9')) ptr++;
value = atoi(ptr);
if (incr)
value+=delta;
else {
if (delta >= value) value = 0;
else value-=delta;
}
sprintf(temp, "%u", value);
res = strlen(temp);
if (res + 2 > it->nbytes) { /* need to realloc */
item *new_it;
new_it = item_alloc(ITEM_key(it), it->flags, it->exptime, res + 2 );
if (new_it == 0) {
out_string(c, "SERVER_ERROR out of memory");
return;
}
memcpy(ITEM_data(new_it), temp, res);
memcpy(ITEM_data(new_it) + res, "\r\n", 2);
item_replace(it, new_it);
} else { /* replace in-place */
memcpy(ITEM_data(it), temp, res);
memset(ITEM_data(it) + res, ' ', it->nbytes-res-2);
}
out_string(c, temp);
return;
}
if (strncmp(command, "get ", 4) == 0) {
char *start = command + 4;
char key[251];
int next;
int i = 0;
item *it;
time_t now = time(0);
while(sscanf(start, " %250s%n", key, &next) >= 1) {
start+=next;
stats.get_cmds++;
it = assoc_find(key);
if (it && (it->it_flags & ITEM_DELETED)) {
it = 0;
}
if (settings.oldest_live && it &&
it->time <= settings.oldest_live) {
item_unlink(it);
it = 0;
}
if (it && it->exptime && it->exptime < now) {
item_unlink(it);
it = 0;
}
if (it) {
if (i >= c->isize) {
item **new_list = realloc(c->ilist, sizeof(item *)*c->isize*2);
if (new_list) {
c->isize *= 2;
c->ilist = new_list;
} else break;
}
stats.get_hits++;
it->refcount++;
item_update(it);
*(c->ilist + i) = it;
i++;
} else stats.get_misses++;
}
c->icurr = c->ilist;
c->ileft = i;
if (c->ileft) {
c->ipart = 0;
c->state = conn_mwrite;
c->ibytes = 0;
return;
} else {
out_string(c, "END");
return;
}
}
if (strncmp(command, "delete ", 7) == 0) {
char key[251];
item *it;
int res;
time_t exptime = 0;
res = sscanf(command, "%*s %250s %ld", key, &exptime);
it = assoc_find(key);
if (!it) {
out_string(c, "NOT_FOUND");
return;
}
if (exptime == 0) {
item_unlink(it);
out_string(c, "DELETED");
return;
}
if (delcurr >= deltotal) {
item **new_delete = realloc(todelete, sizeof(item *) * deltotal * 2);
if (new_delete) {
todelete = new_delete;
deltotal *= 2;
} else {
/*
* can't delete it immediately, user wants a delay,
* but we ran out of memory for the delete queue
*/
out_string(c, "SERVER_ERROR out of memory");
return;
}
}
exptime = realtime(exptime);
it->refcount++;
/* use its expiration time as its deletion time now */
it->exptime = exptime;
it->it_flags |= ITEM_DELETED;
todelete[delcurr++] = it;
out_string(c, "DELETED");
return;
}
if (strncmp(command, "stats", 5) == 0) {
process_stat(c, command);
return;
}
if (strcmp(command, "flush_all") == 0) {
settings.oldest_live = time(0);
out_string(c, "OK");
return;
}
if (strcmp(command, "version") == 0) {
out_string(c, "VERSION " VERSION);
return;
}
if (strcmp(command, "quit") == 0) {
c->state = conn_closing;
return;
}
if (strncmp(command, "slabs reassign ", 15) == 0) {
int src, dst;
char *start = command+15;
if (sscanf(start, "%u %u\r\n", &src, &dst) == 2) {
int rv = slabs_reassign(src, dst);
if (rv == 1) {
out_string(c, "DONE");
return;
}
if (rv == 0) {
out_string(c, "CANT");
return;
}
if (rv == -1) {
out_string(c, "BUSY");
return;
}
}
out_string(c, "CLIENT_ERROR bogus command");
return;
}
out_string(c, "ERROR");
return;
}
