mirror of
https://github.com/fluencelabs/redis
synced 2025-03-19 00:50:50 +00:00
SCAN: refactored into scanGenericCommand.
The new implementation is capable of iterating the keyspace but also sets, hashes, and sorted sets, and can be used to implement SSCAN, ZSCAN and HSCAN.
This commit is contained in:
antirez
parent
7bd45659b9
commit
442ae833b2
140
src/db.c
140
src/db.c
@ -319,32 +319,76 @@ void keysCommand(redisClient *c) {
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setDeferredMultiBulkLength(c,replylen,numkeys);
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}
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/* This callback is used by scanGenericCommand in order to collect elements
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* returned by the dictionary iterator into a list. */
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void scanCallback(void *privdata, const dictEntry *de) {
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list *keys = (list *)privdata;
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sds key = dictGetKey(de);
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robj *kobj = createStringObject(key, sdslen(key));
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listAddNodeTail(keys, kobj);
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void **pd = (void**) privdata;
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list *keys = pd[0];
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robj *o = pd[1];
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robj *key, *val = NULL;
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if (o == NULL) {
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sds sdskey = dictGetKey(de);
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key = createStringObject(sdskey, sdslen(sdskey));
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} else if (o->type == REDIS_SET) {
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key = dictGetKey(de);
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incrRefCount(key);
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} else if (o->type == REDIS_HASH) {
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key = dictGetKey(de);
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incrRefCount(key);
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val = dictGetVal(de);
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incrRefCount(val);
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} else if (o->type == REDIS_ZSET) {
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key = dictGetKey(de);
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incrRefCount(key);
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val = createStringObjectFromLongDouble(*(double*)dictGetVal(de));
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} else {
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redisPanic("Type not handled in SCAN callback.");
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}
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listAddNodeTail(keys, key);
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if (val) listAddNodeTail(keys, val);
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}
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void scanCommand(redisClient *c) {
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/* This command implements SCAN, HSCAN and SSCAN commands.
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* If object 'o' is passed, then it must be an Hash or Set object, otherwise
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* if 'o' is NULL the command will operate on the dictionary associated with
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* the current database.
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*
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* When 'o' is not NULL the function assumes that the first argument in
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* the client arguments vector is a key so it skips it before iterating
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* in order to parse options.
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*
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* In the case of an Hash object the function returns both the field and value
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* of every element on the Hash. */
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void scanGenericCommand(redisClient *c, robj *o) {
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int rv;
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int i, j;
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char buf[REDIS_LONGSTR_SIZE];
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list *keys = listCreate();
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listNode *node, *nextnode;
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unsigned long cursor = 0;
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long count = 1;
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long count = 10;
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sds pat;
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int patlen, patnoop = 1;
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dict *ht;
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/* Object must be NULL (to iterate keys names), or the type of the object
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* must be Set, Sorted Set, or Hash. */
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redisAssert(o == NULL || o->type == REDIS_SET || o->type == REDIS_HASH ||
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o->type == REDIS_ZSET);
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/* Set i to the first option argument. The previous one is the cursor. */
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i = (o == NULL) ? 2 : 3; /* Skip the key argument if needed. */
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/* Use sscanf because we need an *unsigned* long */
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rv = sscanf(c->argv[1]->ptr, "%lu", &cursor);
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rv = sscanf(c->argv[i-1]->ptr, "%lu", &cursor);
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if (rv != 1) {
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addReplyError(c, "invalid cursor");
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goto cleanup;
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}
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i = 2;
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/* Step 1: Parse options. */
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while (i < c->argc) {
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j = c->argc - i;
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if (!strcasecmp(c->argv[i]->ptr, "count") && j >= 2) {
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@ -374,29 +418,92 @@ void scanCommand(redisClient *c) {
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}
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}
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do {
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cursor = dictScan(c->db->dict, cursor, scanCallback, keys);
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} while (cursor && listLength(keys) < count);
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/* Step 2: Iterate the collection.
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*
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* Note that if the object is encoded with a ziplist, intset, or any other
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* representation that is not an hash table, we are sure that it is also
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* composed of a small number of elements. So to avoid taking state we
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* just return everything inside the object in a single call, setting the
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* cursor to zero to signal the end of the iteration. */
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/* Filter keys */
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/* Handle the case of an hash table. */
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ht = NULL;
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if (o == NULL) {
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ht = c->db->dict;
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} else if (o->type == REDIS_SET && o->encoding == REDIS_ENCODING_HT) {
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ht = o->ptr;
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} else if (o->type == REDIS_HASH && o->encoding == REDIS_ENCODING_HT) {
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ht = o->ptr;
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count *= 2; /* We return key / value for this type. */
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} else if (o->type == REDIS_ZSET && o->encoding == REDIS_ENCODING_SKIPLIST) {
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zset *zs = o->ptr;
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ht = zs->dict;
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count *= 2; /* We return key / value for this type. */
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}
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if (ht) {
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void *privdata[2];
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/* We pass two pointers to the callback: the list to which it will
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* add new elements, and the object containing the dictionary so that
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* it is possible to fetch more data in a type-dependent way. */
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privdata[0] = keys;
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privdata[1] = o;
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do {
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cursor = dictScan(ht, cursor, scanCallback, privdata);
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} while (cursor && listLength(keys) < count);
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} else if (o->type == REDIS_SET) {
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int pos = 0;
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long long ll;
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while(intsetGet(o->ptr,pos++,&ll))
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listAddNodeTail(keys,createStringObjectFromLongLong(ll));
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} else if (o->type == REDIS_HASH || o->type == REDIS_ZSET) {
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unsigned char *p = ziplistIndex(o->ptr,0);
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unsigned char *vstr;
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unsigned int vlen;
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long long vll;
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while(p) {
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ziplistGet(p,&vstr,&vlen,&vll);
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listAddNodeTail(keys,
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(vstr != NULL) ? createStringObject((char*)vstr,vlen) :
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createStringObjectFromLongLong(vll));
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ziplistNext(o->ptr,p);
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}
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} else {
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redisPanic("Not handled encoding in SCAN.");
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}
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/* Step 3: Filter elements. */
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node = listFirst(keys);
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while (node) {
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robj *kobj = listNodeValue(node);
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nextnode = listNextNode(node);
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/* Keep key iff pattern matches and it hasn't expired */
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/* Keep key iff pattern matches and, if we are iterating the key
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* space, check that the key hasn't expired. */
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if ((patnoop ||
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stringmatchlen(pat, patlen, kobj->ptr, sdslen(kobj->ptr), 0)) &&
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(expireIfNeeded(c->db, kobj) == 0))
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(o != NULL || expireIfNeeded(c->db, kobj) == 0))
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{
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/* Keep */
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} else {
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decrRefCount(kobj);
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listDelNode(keys, node);
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/* Also remove the value for hashes and sorted sets. */
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if (o && (o->type == REDIS_ZSET || o->type == REDIS_HASH)) {
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node = nextnode;
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kobj = listNodeValue(node);
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nextnode = listNextNode(node);
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decrRefCount(kobj);
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listDelNode(keys, node);
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}
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}
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node = nextnode;
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}
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/* Step 4: Reply to the client. */
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addReplyMultiBulkLen(c, 2);
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rv = snprintf(buf, sizeof(buf), "%lu", cursor);
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redisAssert(rv < sizeof(buf));
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@ -415,6 +522,11 @@ cleanup:
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listRelease(keys);
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}
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/* The SCAN command completely relies on scanGenericCommand. */
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void scanCommand(redisClient *c) {
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scanGenericCommand(c,NULL);
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}
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void dbsizeCommand(redisClient *c) {
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addReplyLongLong(c,dictSize(c->db->dict));
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}
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