+/* =========================== Pubsub implementation ======================== */
+
+static void freePubsubPattern(void *p) {
+ pubsubPattern *pat = p;
+
+ decrRefCount(pat->pattern);
+ zfree(pat);
+}
+
+static int listMatchPubsubPattern(void *a, void *b) {
+ pubsubPattern *pa = a, *pb = b;
+
+ return (pa->client == pb->client) &&
+ (equalStringObjects(pa->pattern,pb->pattern));
+}
+
+/* Subscribe a client to a channel. Returns 1 if the operation succeeded, or
+ * 0 if the client was already subscribed to that channel. */
+static int pubsubSubscribeChannel(redisClient *c, robj *channel) {
+ struct dictEntry *de;
+ list *clients = NULL;
+ int retval = 0;
+
+ /* Add the channel to the client -> channels hash table */
+ if (dictAdd(c->pubsub_channels,channel,NULL) == DICT_OK) {
+ retval = 1;
+ incrRefCount(channel);
+ /* Add the client to the channel -> list of clients hash table */
+ de = dictFind(server.pubsub_channels,channel);
+ if (de == NULL) {
+ clients = listCreate();
+ dictAdd(server.pubsub_channels,channel,clients);
+ incrRefCount(channel);
+ } else {
+ clients = dictGetEntryVal(de);
+ }
+ listAddNodeTail(clients,c);
+ }
+ /* Notify the client */
+ addReply(c,shared.mbulk3);
+ addReply(c,shared.subscribebulk);
+ addReplyBulk(c,channel);
+ addReplyLongLong(c,dictSize(c->pubsub_channels)+listLength(c->pubsub_patterns));
+ return retval;
+}
+
+/* Unsubscribe a client from a channel. Returns 1 if the operation succeeded, or
+ * 0 if the client was not subscribed to the specified channel. */
+static int pubsubUnsubscribeChannel(redisClient *c, robj *channel, int notify) {
+ struct dictEntry *de;
+ list *clients;
+ listNode *ln;
+ int retval = 0;
+
+ /* Remove the channel from the client -> channels hash table */
+ incrRefCount(channel); /* channel may be just a pointer to the same object
+ we have in the hash tables. Protect it... */
+ if (dictDelete(c->pubsub_channels,channel) == DICT_OK) {
+ retval = 1;
+ /* Remove the client from the channel -> clients list hash table */
+ de = dictFind(server.pubsub_channels,channel);
+ assert(de != NULL);
+ clients = dictGetEntryVal(de);
+ ln = listSearchKey(clients,c);
+ assert(ln != NULL);
+ listDelNode(clients,ln);
+ if (listLength(clients) == 0) {
+ /* Free the list and associated hash entry at all if this was
+ * the latest client, so that it will be possible to abuse
+ * Redis PUBSUB creating millions of channels. */
+ dictDelete(server.pubsub_channels,channel);
+ }
+ }
+ /* Notify the client */
+ if (notify) {
+ addReply(c,shared.mbulk3);
+ addReply(c,shared.unsubscribebulk);
+ addReplyBulk(c,channel);
+ addReplyLongLong(c,dictSize(c->pubsub_channels)+
+ listLength(c->pubsub_patterns));
+
+ }
+ decrRefCount(channel); /* it is finally safe to release it */
+ return retval;
+}
+
+/* Subscribe a client to a pattern. Returns 1 if the operation succeeded, or 0 if the clinet was already subscribed to that pattern. */
+static int pubsubSubscribePattern(redisClient *c, robj *pattern) {
+ int retval = 0;
+
+ if (listSearchKey(c->pubsub_patterns,pattern) == NULL) {
+ retval = 1;
+ pubsubPattern *pat;
+ listAddNodeTail(c->pubsub_patterns,pattern);
+ incrRefCount(pattern);
+ pat = zmalloc(sizeof(*pat));
+ pat->pattern = getDecodedObject(pattern);
+ pat->client = c;
+ listAddNodeTail(server.pubsub_patterns,pat);
+ }
+ /* Notify the client */
+ addReply(c,shared.mbulk3);
+ addReply(c,shared.psubscribebulk);
+ addReplyBulk(c,pattern);
+ addReplyLongLong(c,dictSize(c->pubsub_channels)+listLength(c->pubsub_patterns));
+ return retval;
+}
+
+/* Unsubscribe a client from a channel. Returns 1 if the operation succeeded, or
+ * 0 if the client was not subscribed to the specified channel. */
+static int pubsubUnsubscribePattern(redisClient *c, robj *pattern, int notify) {
+ listNode *ln;
+ pubsubPattern pat;
+ int retval = 0;
+
+ incrRefCount(pattern); /* Protect the object. May be the same we remove */
+ if ((ln = listSearchKey(c->pubsub_patterns,pattern)) != NULL) {
+ retval = 1;
+ listDelNode(c->pubsub_patterns,ln);
+ pat.client = c;
+ pat.pattern = pattern;
+ ln = listSearchKey(server.pubsub_patterns,&pat);
+ listDelNode(server.pubsub_patterns,ln);
+ }
+ /* Notify the client */
+ if (notify) {
+ addReply(c,shared.mbulk3);
+ addReply(c,shared.punsubscribebulk);
+ addReplyBulk(c,pattern);
+ addReplyLongLong(c,dictSize(c->pubsub_channels)+
+ listLength(c->pubsub_patterns));
+ }
+ decrRefCount(pattern);
+ return retval;
+}
+
+/* Unsubscribe from all the channels. Return the number of channels the
+ * client was subscribed from. */
+static int pubsubUnsubscribeAllChannels(redisClient *c, int notify) {
+ dictIterator *di = dictGetIterator(c->pubsub_channels);
+ dictEntry *de;
+ int count = 0;
+
+ while((de = dictNext(di)) != NULL) {
+ robj *channel = dictGetEntryKey(de);
+
+ count += pubsubUnsubscribeChannel(c,channel,notify);
+ }
+ dictReleaseIterator(di);
+ return count;
+}
+
+/* Unsubscribe from all the patterns. Return the number of patterns the
+ * client was subscribed from. */
+static int pubsubUnsubscribeAllPatterns(redisClient *c, int notify) {
+ listNode *ln;
+ listIter li;
+ int count = 0;
+
+ listRewind(c->pubsub_patterns,&li);
+ while ((ln = listNext(&li)) != NULL) {
+ robj *pattern = ln->value;
+
+ count += pubsubUnsubscribePattern(c,pattern,notify);
+ }
+ return count;
+}
+
+/* Publish a message */
+static int pubsubPublishMessage(robj *channel, robj *message) {
+ int receivers = 0;
+ struct dictEntry *de;
+ listNode *ln;
+ listIter li;
+
+ /* Send to clients listening for that channel */
+ de = dictFind(server.pubsub_channels,channel);
+ if (de) {
+ list *list = dictGetEntryVal(de);
+ listNode *ln;
+ listIter li;
+
+ listRewind(list,&li);
+ while ((ln = listNext(&li)) != NULL) {
+ redisClient *c = ln->value;
+
+ addReply(c,shared.mbulk3);
+ addReply(c,shared.messagebulk);
+ addReplyBulk(c,channel);
+ addReplyBulk(c,message);
+ receivers++;
+ }
+ }
+ /* Send to clients listening to matching channels */
+ if (listLength(server.pubsub_patterns)) {
+ listRewind(server.pubsub_patterns,&li);
+ channel = getDecodedObject(channel);
+ while ((ln = listNext(&li)) != NULL) {
+ pubsubPattern *pat = ln->value;
+
+ if (stringmatchlen((char*)pat->pattern->ptr,
+ sdslen(pat->pattern->ptr),
+ (char*)channel->ptr,
+ sdslen(channel->ptr),0)) {
+ addReply(pat->client,shared.mbulk4);
+ addReply(pat->client,shared.pmessagebulk);
+ addReplyBulk(pat->client,pat->pattern);
+ addReplyBulk(pat->client,channel);
+ addReplyBulk(pat->client,message);
+ receivers++;
+ }
+ }
+ decrRefCount(channel);
+ }
+ return receivers;
+}
+
+static void subscribeCommand(redisClient *c) {
+ int j;
+
+ for (j = 1; j < c->argc; j++)
+ pubsubSubscribeChannel(c,c->argv[j]);
+}
+
+static void unsubscribeCommand(redisClient *c) {
+ if (c->argc == 1) {
+ pubsubUnsubscribeAllChannels(c,1);
+ return;
+ } else {
+ int j;
+
+ for (j = 1; j < c->argc; j++)
+ pubsubUnsubscribeChannel(c,c->argv[j],1);
+ }
+}
+
+static void psubscribeCommand(redisClient *c) {
+ int j;
+
+ for (j = 1; j < c->argc; j++)
+ pubsubSubscribePattern(c,c->argv[j]);
+}
+
+static void punsubscribeCommand(redisClient *c) {
+ if (c->argc == 1) {
+ pubsubUnsubscribeAllPatterns(c,1);
+ return;
+ } else {
+ int j;
+
+ for (j = 1; j < c->argc; j++)
+ pubsubUnsubscribePattern(c,c->argv[j],1);
+ }
+}
+
+static void publishCommand(redisClient *c) {
+ int receivers = pubsubPublishMessage(c->argv[1],c->argv[2]);
+ addReplyLongLong(c,receivers);
+}
+
+/* ===================== WATCH (CAS alike for MULTI/EXEC) ===================
+ *
+ * The implementation uses a per-DB hash table mapping keys to list of clients
+ * WATCHing those keys, so that given a key that is going to be modified
+ * we can mark all the associated clients as dirty.
+ *
+ * Also every client contains a list of WATCHed keys so that's possible to
+ * un-watch such keys when the client is freed or when UNWATCH is called. */
+
+/* In the client->watched_keys list we need to use watchedKey structures
+ * as in order to identify a key in Redis we need both the key name and the
+ * DB */
+typedef struct watchedKey {
+ robj *key;
+ redisDb *db;
+} watchedKey;
+
+/* Watch for the specified key */
+static void watchForKey(redisClient *c, robj *key) {
+ list *clients = NULL;
+ listIter li;
+ listNode *ln;
+ watchedKey *wk;
+
+ /* Check if we are already watching for this key */
+ listRewind(c->watched_keys,&li);
+ while((ln = listNext(&li))) {
+ wk = listNodeValue(ln);
+ if (wk->db == c->db && equalStringObjects(key,wk->key))
+ return; /* Key already watched */
+ }
+ /* This key is not already watched in this DB. Let's add it */
+ clients = dictFetchValue(c->db->watched_keys,key);
+ if (!clients) {
+ clients = listCreate();
+ dictAdd(c->db->watched_keys,key,clients);
+ incrRefCount(key);
+ }
+ listAddNodeTail(clients,c);
+ /* Add the new key to the lits of keys watched by this client */
+ wk = zmalloc(sizeof(*wk));
+ wk->key = key;
+ wk->db = c->db;
+ incrRefCount(key);
+ listAddNodeTail(c->watched_keys,wk);
+}
+
+/* Unwatch all the keys watched by this client. To clean the EXEC dirty
+ * flag is up to the caller. */
+static void unwatchAllKeys(redisClient *c) {
+ listIter li;
+ listNode *ln;
+
+ if (listLength(c->watched_keys) == 0) return;
+ listRewind(c->watched_keys,&li);
+ while((ln = listNext(&li))) {
+ list *clients;
+ watchedKey *wk;
+
+ /* Lookup the watched key -> clients list and remove the client
+ * from the list */
+ wk = listNodeValue(ln);
+ clients = dictFetchValue(wk->db->watched_keys, wk->key);
+ assert(clients != NULL);
+ listDelNode(clients,listSearchKey(clients,c));
+ /* Kill the entry at all if this was the only client */
+ if (listLength(clients) == 0)
+ dictDelete(wk->db->watched_keys, wk->key);
+ /* Remove this watched key from the client->watched list */
+ listDelNode(c->watched_keys,ln);
+ decrRefCount(wk->key);
+ zfree(wk);
+ }
+}
+
+/* "Touch" a key, so that if this key is being WATCHed by some client the
+ * next EXEC will fail. */
+static void touchWatchedKey(redisDb *db, robj *key) {
+ list *clients;
+ listIter li;
+ listNode *ln;
+
+ if (dictSize(db->watched_keys) == 0) return;
+ clients = dictFetchValue(db->watched_keys, key);
+ if (!clients) return;
+
+ /* Mark all the clients watching this key as REDIS_DIRTY_CAS */
+ /* Check if we are already watching for this key */
+ listRewind(clients,&li);
+ while((ln = listNext(&li))) {
+ redisClient *c = listNodeValue(ln);
+
+ c->flags |= REDIS_DIRTY_CAS;
+ }
+}
+
+/* On FLUSHDB or FLUSHALL all the watched keys that are present before the
+ * flush but will be deleted as effect of the flushing operation should
+ * be touched. "dbid" is the DB that's getting the flush. -1 if it is
+ * a FLUSHALL operation (all the DBs flushed). */
+static void touchWatchedKeysOnFlush(int dbid) {
+ listIter li1, li2;
+ listNode *ln;
+
+ /* For every client, check all the waited keys */
+ listRewind(server.clients,&li1);
+ while((ln = listNext(&li1))) {
+ redisClient *c = listNodeValue(ln);
+ listRewind(c->watched_keys,&li2);
+ while((ln = listNext(&li2))) {
+ watchedKey *wk = listNodeValue(ln);
+
+ /* For every watched key matching the specified DB, if the
+ * key exists, mark the client as dirty, as the key will be
+ * removed. */
+ if (dbid == -1 || wk->db->id == dbid) {
+ if (dictFind(wk->db->dict, wk->key) != NULL)
+ c->flags |= REDIS_DIRTY_CAS;
+ }
+ }
+ }
+}
+
+static void watchCommand(redisClient *c) {
+ int j;
+
+ if (c->flags & REDIS_MULTI) {
+ addReplySds(c,sdsnew("-ERR WATCH inside MULTI is not allowed\r\n"));
+ return;
+ }
+ for (j = 1; j < c->argc; j++)
+ watchForKey(c,c->argv[j]);
+ addReply(c,shared.ok);
+}
+
+static void unwatchCommand(redisClient *c) {
+ unwatchAllKeys(c);
+ c->flags &= (~REDIS_DIRTY_CAS);
+ addReply(c,shared.ok);
+}
+
projects / redis.git / blobdiff