+/*
+ * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * * Neither the name of Redis nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
#include "redis.h"
+void signalListAsReady(redisClient *c, robj *key);
+
/*-----------------------------------------------------------------------------
* List API
*----------------------------------------------------------------------------*/
listTypeConvert(subject,REDIS_ENCODING_LINKEDLIST);
}
+/* The function pushes an elmenet to the specified list object 'subject',
+ * at head or tail position as specified by 'where'.
+ *
+ * There is no need for the caller to incremnet the refcount of 'value' as
+ * the function takes care of it if needed. */
void listTypePush(robj *subject, robj *value, int where) {
/* Check if we need to convert the ziplist */
listTypeTryConversion(subject,value);
}
/* Initialize an iterator at the specified index. */
-listTypeIterator *listTypeInitIterator(robj *subject, int index, unsigned char direction) {
+listTypeIterator *listTypeInitIterator(robj *subject, long index, unsigned char direction) {
listTypeIterator *li = zmalloc(sizeof(listTypeIterator));
li->subject = subject;
li->encoding = subject->encoding;
int listTypeEqual(listTypeEntry *entry, robj *o) {
listTypeIterator *li = entry->li;
if (li->encoding == REDIS_ENCODING_ZIPLIST) {
- redisAssert(o->encoding == REDIS_ENCODING_RAW);
+ redisAssertWithInfo(NULL,o,o->encoding == REDIS_ENCODING_RAW);
return ziplistCompare(entry->zi,o->ptr,sdslen(o->ptr));
} else if (li->encoding == REDIS_ENCODING_LINKEDLIST) {
return equalStringObjects(o,listNodeValue(entry->ln));
void listTypeConvert(robj *subject, int enc) {
listTypeIterator *li;
listTypeEntry entry;
- redisAssert(subject->type == REDIS_LIST);
+ redisAssertWithInfo(NULL,subject,subject->type == REDIS_LIST);
if (enc == REDIS_ENCODING_LINKEDLIST) {
list *l = listCreate();
*----------------------------------------------------------------------------*/
void pushGenericCommand(redisClient *c, int where) {
+ int j, waiting = 0, pushed = 0;
robj *lobj = lookupKeyWrite(c->db,c->argv[1]);
- if (lobj == NULL) {
- if (handleClientsWaitingListPush(c,c->argv[1],c->argv[2])) {
- addReply(c,shared.cone);
- return;
- }
- lobj = createZiplistObject();
- dbAdd(c->db,c->argv[1],lobj);
- } else {
- if (lobj->type != REDIS_LIST) {
- addReply(c,shared.wrongtypeerr);
- return;
- }
- if (handleClientsWaitingListPush(c,c->argv[1],c->argv[2])) {
- addReply(c,shared.cone);
- return;
+ int may_have_waiting_clients = (lobj == NULL);
+
+ if (lobj && lobj->type != REDIS_LIST) {
+ addReply(c,shared.wrongtypeerr);
+ return;
+ }
+
+ if (may_have_waiting_clients) signalListAsReady(c,c->argv[1]);
+
+ for (j = 2; j < c->argc; j++) {
+ c->argv[j] = tryObjectEncoding(c->argv[j]);
+ if (!lobj) {
+ lobj = createZiplistObject();
+ dbAdd(c->db,c->argv[1],lobj);
}
+ listTypePush(lobj,c->argv[j],where);
+ pushed++;
}
- listTypePush(lobj,c->argv[2],where);
- addReplyLongLong(c,listTypeLength(lobj));
- server.dirty++;
+ addReplyLongLong(c, waiting + (lobj ? listTypeLength(lobj) : 0));
+ if (pushed) signalModifiedKey(c->db,c->argv[1]);
+ server.dirty += pushed;
}
void lpushCommand(redisClient *c) {
if (refval != NULL) {
/* Note: we expect refval to be string-encoded because it is *not* the
* last argument of the multi-bulk LINSERT. */
- redisAssert(refval->encoding == REDIS_ENCODING_RAW);
+ redisAssertWithInfo(c,refval,refval->encoding == REDIS_ENCODING_RAW);
/* We're not sure if this value can be inserted yet, but we cannot
* convert the list inside the iterator. We don't want to loop over
if (subject->encoding == REDIS_ENCODING_ZIPLIST &&
ziplistLen(subject->ptr) > server.list_max_ziplist_entries)
listTypeConvert(subject,REDIS_ENCODING_LINKEDLIST);
+ signalModifiedKey(c->db,c->argv[1]);
server.dirty++;
} else {
/* Notify client of a failed insert */
}
} else {
listTypePush(subject,val,where);
+ signalModifiedKey(c->db,c->argv[1]);
server.dirty++;
}
- addReplyUlong(c,listTypeLength(subject));
+ addReplyLongLong(c,listTypeLength(subject));
}
void lpushxCommand(redisClient *c) {
+ c->argv[2] = tryObjectEncoding(c->argv[2]);
pushxGenericCommand(c,NULL,c->argv[2],REDIS_HEAD);
}
void rpushxCommand(redisClient *c) {
+ c->argv[2] = tryObjectEncoding(c->argv[2]);
pushxGenericCommand(c,NULL,c->argv[2],REDIS_TAIL);
}
void linsertCommand(redisClient *c) {
+ c->argv[4] = tryObjectEncoding(c->argv[4]);
if (strcasecmp(c->argv[2]->ptr,"after") == 0) {
pushxGenericCommand(c,c->argv[3],c->argv[4],REDIS_TAIL);
} else if (strcasecmp(c->argv[2]->ptr,"before") == 0) {
void llenCommand(redisClient *c) {
robj *o = lookupKeyReadOrReply(c,c->argv[1],shared.czero);
if (o == NULL || checkType(c,o,REDIS_LIST)) return;
- addReplyUlong(c,listTypeLength(o));
+ addReplyLongLong(c,listTypeLength(o));
}
void lindexCommand(redisClient *c) {
robj *o = lookupKeyReadOrReply(c,c->argv[1],shared.nullbulk);
if (o == NULL || checkType(c,o,REDIS_LIST)) return;
- int index = atoi(c->argv[2]->ptr);
+ long index;
robj *value = NULL;
+ if ((getLongFromObjectOrReply(c, c->argv[2], &index, NULL) != REDIS_OK))
+ return;
+
if (o->encoding == REDIS_ENCODING_ZIPLIST) {
unsigned char *p;
unsigned char *vstr;
void lsetCommand(redisClient *c) {
robj *o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr);
if (o == NULL || checkType(c,o,REDIS_LIST)) return;
- int index = atoi(c->argv[2]->ptr);
- robj *value = c->argv[3];
+ long index;
+ robj *value = (c->argv[3] = tryObjectEncoding(c->argv[3]));
+
+ if ((getLongFromObjectOrReply(c, c->argv[2], &index, NULL) != REDIS_OK))
+ return;
listTypeTryConversion(o,value);
if (o->encoding == REDIS_ENCODING_ZIPLIST) {
o->ptr = ziplistInsert(o->ptr,p,value->ptr,sdslen(value->ptr));
decrRefCount(value);
addReply(c,shared.ok);
+ signalModifiedKey(c->db,c->argv[1]);
server.dirty++;
}
} else if (o->encoding == REDIS_ENCODING_LINKEDLIST) {
listNodeValue(ln) = value;
incrRefCount(value);
addReply(c,shared.ok);
+ signalModifiedKey(c->db,c->argv[1]);
server.dirty++;
}
} else {
addReplyBulk(c,value);
decrRefCount(value);
if (listTypeLength(o) == 0) dbDelete(c->db,c->argv[1]);
+ signalModifiedKey(c->db,c->argv[1]);
server.dirty++;
}
}
}
void lrangeCommand(redisClient *c) {
- robj *o, *value;
- int start = atoi(c->argv[2]->ptr);
- int end = atoi(c->argv[3]->ptr);
- int llen;
- int rangelen, j;
- listTypeEntry entry;
+ robj *o;
+ long start, end, llen, rangelen;
+
+ if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != REDIS_OK) ||
+ (getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != REDIS_OK)) return;
if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.emptymultibulk)) == NULL
|| checkType(c,o,REDIS_LIST)) return;
if (start < 0) start = llen+start;
if (end < 0) end = llen+end;
if (start < 0) start = 0;
- if (end < 0) end = 0;
- /* indexes sanity checks */
+ /* Invariant: start >= 0, so this test will be true when end < 0.
+ * The range is empty when start > end or start >= length. */
if (start > end || start >= llen) {
- /* Out of range start or start > end result in empty list */
addReply(c,shared.emptymultibulk);
return;
}
rangelen = (end-start)+1;
/* Return the result in form of a multi-bulk reply */
- addReplySds(c,sdscatprintf(sdsempty(),"*%d\r\n",rangelen));
- listTypeIterator *li = listTypeInitIterator(o,start,REDIS_TAIL);
- for (j = 0; j < rangelen; j++) {
- redisAssert(listTypeNext(li,&entry));
- value = listTypeGet(&entry);
- addReplyBulk(c,value);
- decrRefCount(value);
+ addReplyMultiBulkLen(c,rangelen);
+ if (o->encoding == REDIS_ENCODING_ZIPLIST) {
+ unsigned char *p = ziplistIndex(o->ptr,start);
+ unsigned char *vstr;
+ unsigned int vlen;
+ long long vlong;
+
+ while(rangelen--) {
+ ziplistGet(p,&vstr,&vlen,&vlong);
+ if (vstr) {
+ addReplyBulkCBuffer(c,vstr,vlen);
+ } else {
+ addReplyBulkLongLong(c,vlong);
+ }
+ p = ziplistNext(o->ptr,p);
+ }
+ } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) {
+ listNode *ln;
+
+ /* If we are nearest to the end of the list, reach the element
+ * starting from tail and going backward, as it is faster. */
+ if (start > llen/2) start -= llen;
+ ln = listIndex(o->ptr,start);
+
+ while(rangelen--) {
+ addReplyBulk(c,ln->value);
+ ln = ln->next;
+ }
+ } else {
+ redisPanic("List encoding is not LINKEDLIST nor ZIPLIST!");
}
- listTypeReleaseIterator(li);
}
void ltrimCommand(redisClient *c) {
robj *o;
- int start = atoi(c->argv[2]->ptr);
- int end = atoi(c->argv[3]->ptr);
- int llen;
- int j, ltrim, rtrim;
+ long start, end, llen, j, ltrim, rtrim;
list *list;
listNode *ln;
+ if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != REDIS_OK) ||
+ (getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != REDIS_OK)) return;
+
if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.ok)) == NULL ||
checkType(c,o,REDIS_LIST)) return;
llen = listTypeLength(o);
if (start < 0) start = llen+start;
if (end < 0) end = llen+end;
if (start < 0) start = 0;
- if (end < 0) end = 0;
- /* indexes sanity checks */
+ /* Invariant: start >= 0, so this test will be true when end < 0.
+ * The range is empty when start > end or start >= length. */
if (start > end || start >= llen) {
/* Out of range start or start > end result in empty list */
ltrim = llen;
redisPanic("Unknown list encoding");
}
if (listTypeLength(o) == 0) dbDelete(c->db,c->argv[1]);
+ signalModifiedKey(c->db,c->argv[1]);
server.dirty++;
addReply(c,shared.ok);
}
void lremCommand(redisClient *c) {
- robj *subject, *obj = c->argv[3];
- int toremove = atoi(c->argv[2]->ptr);
- int removed = 0;
+ robj *subject, *obj;
+ obj = c->argv[3] = tryObjectEncoding(c->argv[3]);
+ long toremove;
+ long removed = 0;
listTypeEntry entry;
+ if ((getLongFromObjectOrReply(c, c->argv[2], &toremove, NULL) != REDIS_OK))
+ return;
+
subject = lookupKeyWriteOrReply(c,c->argv[1],shared.czero);
if (subject == NULL || checkType(c,subject,REDIS_LIST)) return;
decrRefCount(obj);
if (listTypeLength(subject) == 0) dbDelete(c->db,c->argv[1]);
- addReplySds(c,sdscatprintf(sdsempty(),":%d\r\n",removed));
+ addReplyLongLong(c,removed);
+ if (removed) signalModifiedKey(c->db,c->argv[1]);
}
/* This is the semantic of this command:
* RPOPLPUSH srclist dstlist:
- * IF LLEN(srclist) > 0
- * element = RPOP srclist
- * LPUSH dstlist element
- * RETURN element
- * ELSE
- * RETURN nil
- * END
+ * IF LLEN(srclist) > 0
+ * element = RPOP srclist
+ * LPUSH dstlist element
+ * RETURN element
+ * ELSE
+ * RETURN nil
+ * END
* END
*
* The idea is to be able to get an element from a list in a reliable way
* since the element is not just returned but pushed against another list
* as well. This command was originally proposed by Ezra Zygmuntowicz.
*/
-void rpoplpushcommand(redisClient *c) {
+
+void rpoplpushHandlePush(redisClient *c, robj *dstkey, robj *dstobj, robj *value) {
+ /* Create the list if the key does not exist */
+ if (!dstobj) {
+ dstobj = createZiplistObject();
+ dbAdd(c->db,dstkey,dstobj);
+ signalListAsReady(c,dstkey);
+ }
+ signalModifiedKey(c->db,dstkey);
+ listTypePush(dstobj,value,REDIS_HEAD);
+ /* Always send the pushed value to the client. */
+ addReplyBulk(c,value);
+}
+
+void rpoplpushCommand(redisClient *c) {
robj *sobj, *value;
if ((sobj = lookupKeyWriteOrReply(c,c->argv[1],shared.nullbulk)) == NULL ||
checkType(c,sobj,REDIS_LIST)) return;
if (listTypeLength(sobj) == 0) {
+ /* This may only happen after loading very old RDB files. Recent
+ * versions of Redis delete keys of empty lists. */
addReply(c,shared.nullbulk);
} else {
robj *dobj = lookupKeyWrite(c->db,c->argv[2]);
+ robj *touchedkey = c->argv[1];
+
if (dobj && checkType(c,dobj,REDIS_LIST)) return;
value = listTypePop(sobj,REDIS_TAIL);
-
- /* Add the element to the target list (unless it's directly
- * passed to some BLPOP-ing client */
- if (!handleClientsWaitingListPush(c,c->argv[2],value)) {
- /* Create the list if the key does not exist */
- if (!dobj) {
- dobj = createZiplistObject();
- dbAdd(c->db,c->argv[2],dobj);
- }
- listTypePush(dobj,value,REDIS_HEAD);
- }
-
- /* Send the element to the client as reply as well */
- addReplyBulk(c,value);
+ /* We saved touched key, and protect it, since rpoplpushHandlePush
+ * may change the client command argument vector (it does not
+ * currently). */
+ incrRefCount(touchedkey);
+ rpoplpushHandlePush(c,c->argv[2],dobj,value);
/* listTypePop returns an object with its refcount incremented */
decrRefCount(value);
/* Delete the source list when it is empty */
- if (listTypeLength(sobj) == 0) dbDelete(c->db,c->argv[1]);
+ if (listTypeLength(sobj) == 0) dbDelete(c->db,touchedkey);
+ signalModifiedKey(c->db,touchedkey);
+ decrRefCount(touchedkey);
server.dirty++;
}
}
* Blocking POP operations
*----------------------------------------------------------------------------*/
-/* Currently Redis blocking operations support is limited to list POP ops,
- * so the current implementation is not fully generic, but it is also not
- * completely specific so it will not require a rewrite to support new
- * kind of blocking operations in the future.
- *
- * Still it's important to note that list blocking operations can be already
- * used as a notification mechanism in order to implement other blocking
- * operations at application level, so there must be a very strong evidence
- * of usefulness and generality before new blocking operations are implemented.
- *
- * This is how the current blocking POP works, we use BLPOP as example:
+/* This is how the current blocking POP works, we use BLPOP as example:
* - If the user calls BLPOP and the key exists and contains a non empty list
* then LPOP is called instead. So BLPOP is semantically the same as LPOP
- * if there is not to block.
+ * if blocking is not required.
* - If instead BLPOP is called and the key does not exists or the list is
* empty we need to block. In order to do so we remove the notification for
* new data to read in the client socket (so that we'll not serve new
* in a dictionary (db->blocking_keys) mapping keys to a list of clients
* blocking for this keys.
* - If a PUSH operation against a key with blocked clients waiting is
- * performed, we serve the first in the list: basically instead to push
- * the new element inside the list we return it to the (first / oldest)
- * blocking client, unblock the client, and remove it form the list.
- *
- * The above comment and the source code should be enough in order to understand
- * the implementation and modify / fix it later.
+ * performed, we mark this key as "ready", and after the current command,
+ * MULTI/EXEC block, or script, is executed, we serve all the clients waiting
+ * for this list, from the one that blocked first, to the last, accordingly
+ * to the number of elements we have in the ready list.
*/
/* Set a client in blocking mode for the specified key, with the specified
* timeout */
-void blockForKeys(redisClient *c, robj **keys, int numkeys, time_t timeout) {
+void blockForKeys(redisClient *c, robj **keys, int numkeys, time_t timeout, robj *target) {
+ dict *added;
dictEntry *de;
list *l;
- int j;
+ int j, i;
+
+ c->bpop.keys = zmalloc(sizeof(robj*)*numkeys);
+ c->bpop.timeout = timeout;
+ c->bpop.target = target;
+
+ if (target != NULL) incrRefCount(target);
- c->blocking_keys = zmalloc(sizeof(robj*)*numkeys);
- c->blocking_keys_num = numkeys;
- c->blockingto = timeout;
+ /* Create a dictionary that we use to avoid adding duplicated keys
+ * in case the user calls something like: "BLPOP foo foo foo 0".
+ * The rest of the implementation is simpler if we know there are no
+ * duplications in the key waiting list. */
+ added = dictCreate(&setDictType,NULL);
+
+ i = 0; /* The index for c->bpop.keys[...], we can't use the j loop
+ variable as the list of keys may have duplicated elements. */
for (j = 0; j < numkeys; j++) {
+ /* Add the key in the "added" dictionary to make sure there are
+ * no duplicated keys. */
+ if (dictAdd(added,keys[j],NULL) != DICT_OK) continue;
+ incrRefCount(keys[j]);
+
/* Add the key in the client structure, to map clients -> keys */
- c->blocking_keys[j] = keys[j];
+ c->bpop.keys[i++] = keys[j];
incrRefCount(keys[j]);
/* And in the other "side", to map keys -> clients */
l = listCreate();
retval = dictAdd(c->db->blocking_keys,keys[j],l);
incrRefCount(keys[j]);
- redisAssert(retval == DICT_OK);
+ redisAssertWithInfo(c,keys[j],retval == DICT_OK);
} else {
- l = dictGetEntryVal(de);
+ l = dictGetVal(de);
}
listAddNodeTail(l,c);
}
+ c->bpop.count = i;
+
/* Mark the client as a blocked client */
c->flags |= REDIS_BLOCKED;
- server.blpop_blocked_clients++;
+ server.bpop_blocked_clients++;
+ dictRelease(added);
}
/* Unblock a client that's waiting in a blocking operation such as BLPOP */
list *l;
int j;
- redisAssert(c->blocking_keys != NULL);
+ redisAssertWithInfo(c,NULL,c->bpop.keys != NULL);
/* The client may wait for multiple keys, so unblock it for every key. */
- for (j = 0; j < c->blocking_keys_num; j++) {
+ for (j = 0; j < c->bpop.count; j++) {
/* Remove this client from the list of clients waiting for this key. */
- de = dictFind(c->db->blocking_keys,c->blocking_keys[j]);
- redisAssert(de != NULL);
- l = dictGetEntryVal(de);
+ de = dictFind(c->db->blocking_keys,c->bpop.keys[j]);
+ redisAssertWithInfo(c,c->bpop.keys[j],de != NULL);
+ l = dictGetVal(de);
listDelNode(l,listSearchKey(l,c));
/* If the list is empty we need to remove it to avoid wasting memory */
if (listLength(l) == 0)
- dictDelete(c->db->blocking_keys,c->blocking_keys[j]);
- decrRefCount(c->blocking_keys[j]);
+ dictDelete(c->db->blocking_keys,c->bpop.keys[j]);
+ decrRefCount(c->bpop.keys[j]);
}
+
/* Cleanup the client structure */
- zfree(c->blocking_keys);
- c->blocking_keys = NULL;
- c->flags &= (~REDIS_BLOCKED);
- server.blpop_blocked_clients--;
- /* We want to process data if there is some command waiting
- * in the input buffer. Note that this is safe even if
- * unblockClientWaitingData() gets called from freeClient() because
- * freeClient() will be smart enough to call this function
- * *after* c->querybuf was set to NULL. */
- if (c->querybuf && sdslen(c->querybuf) > 0) processInputBuffer(c);
-}
-
-/* This should be called from any function PUSHing into lists.
- * 'c' is the "pushing client", 'key' is the key it is pushing data against,
- * 'ele' is the element pushed.
+ zfree(c->bpop.keys);
+ c->bpop.keys = NULL;
+ if (c->bpop.target) decrRefCount(c->bpop.target);
+ c->bpop.target = NULL;
+ c->flags &= ~REDIS_BLOCKED;
+ c->flags |= REDIS_UNBLOCKED;
+ server.bpop_blocked_clients--;
+ listAddNodeTail(server.unblocked_clients,c);
+}
+
+/* If the specified key has clients blocked waiting for list pushes, this
+ * function will put the key reference into the server.ready_keys list.
+ * Note that db->ready_keys is an hash table that allows us to avoid putting
+ * the same key agains and again in the list in case of multiple pushes
+ * made by a script or in the context of MULTI/EXEC.
*
- * If the function returns 0 there was no client waiting for a list push
- * against this key.
+ * The list will be finally processed by handleClientsBlockedOnLists() */
+void signalListAsReady(redisClient *c, robj *key) {
+ readyList *rl;
+
+ /* No clients blocking for this key? No need to queue it. */
+ if (dictFind(c->db->blocking_keys,key) == NULL) return;
+
+ /* Key was already signaled? No need to queue it again. */
+ if (dictFind(c->db->ready_keys,key) != NULL) return;
+
+ /* Ok, we need to queue this key into server.ready_keys. */
+ rl = zmalloc(sizeof(*rl));
+ rl->key = key;
+ rl->db = c->db;
+ incrRefCount(key);
+ listAddNodeTail(server.ready_keys,rl);
+
+ /* We also add the key in the db->ready_keys dictionary in order
+ * to avoid adding it multiple times into a list with a simple O(1)
+ * check. */
+ incrRefCount(key);
+ redisAssert(dictAdd(c->db->ready_keys,key,NULL) == DICT_OK);
+}
+
+/* This is an helper function for handleClientsBlockedOnLists(). It's work
+ * is to serve a specific client (receiver) that is blocked on 'key'
+ * in the context of the specified 'db', doing the following:
*
- * If the function returns 1 there was a client waiting for a list push
- * against this key, the element was passed to this client thus it's not
- * needed to actually add it to the list and the caller should return asap. */
-int handleClientsWaitingListPush(redisClient *c, robj *key, robj *ele) {
- struct dictEntry *de;
- redisClient *receiver;
- list *l;
- listNode *ln;
+ * 1) Provide the client with the 'value' element.
+ * 2) If the dstkey is not NULL (we are serving a BRPOPLPUSH) also push the
+ * 'value' element on the destionation list (the LPUSH side of the command).
+ * 3) Propagate the resulting BRPOP, BLPOP and additional LPUSH if any into
+ * the AOF and replication channel.
+ *
+ * The argument 'where' is REDIS_TAIL or REDIS_HEAD, and indicates if the
+ * 'value' element was popped fron the head (BLPOP) or tail (BRPOP) so that
+ * we can propagate the command properly.
+ *
+ * The function returns REDIS_OK if we are able to serve the client, otherwise
+ * REDIS_ERR is returned to signal the caller that the list POP operation
+ * should be undoed as the client was not served: This only happens for
+ * BRPOPLPUSH that fails to push the value to the destination key as it is
+ * of the wrong type. */
+int serveClientBlockedOnList(redisClient *receiver, robj *key, robj *dstkey, redisDb *db, robj *value, int where)
+{
+ robj *argv[3];
+
+ if (dstkey == NULL) {
+ /* Propagate the [LR]POP operation. */
+ argv[0] = (where == REDIS_HEAD) ? shared.lpop :
+ shared.rpop;
+ argv[1] = key;
+ propagate((where == REDIS_HEAD) ?
+ server.lpopCommand : server.rpopCommand,
+ db->id,argv,2,REDIS_PROPAGATE_AOF|REDIS_PROPAGATE_REPL);
+
+ /* BRPOP/BLPOP */
+ addReplyMultiBulkLen(receiver,2);
+ addReplyBulk(receiver,key);
+ addReplyBulk(receiver,value);
+ } else {
+ /* BRPOPLPUSH */
+ robj *dstobj =
+ lookupKeyWrite(receiver->db,dstkey);
+ if (!(dstobj &&
+ checkType(receiver,dstobj,REDIS_LIST)))
+ {
+ /* Propagate the RPOP operation. */
+ argv[0] = shared.rpop;
+ argv[1] = key;
+ propagate(server.rpopCommand,
+ db->id,argv,2,
+ REDIS_PROPAGATE_AOF|
+ REDIS_PROPAGATE_REPL);
+ rpoplpushHandlePush(receiver,dstkey,dstobj,
+ value);
+ /* Propagate the LPUSH operation. */
+ argv[0] = shared.lpush;
+ argv[1] = dstkey;
+ argv[2] = value;
+ propagate(server.lpushCommand,
+ db->id,argv,3,
+ REDIS_PROPAGATE_AOF|
+ REDIS_PROPAGATE_REPL);
+ } else {
+ /* BRPOPLPUSH failed because of wrong
+ * destination type. */
+ return REDIS_ERR;
+ }
+ }
+ return REDIS_OK;
+}
+
+/* This function should be called by Redis every time a single command,
+ * a MULTI/EXEC block, or a Lua script, terminated its execution after
+ * being called by a client.
+ *
+ * All the keys with at least one client blocked that received at least
+ * one new element via some PUSH operation are accumulated into
+ * the server.ready_keys list. This function will run the list and will
+ * serve clients accordingly. Note that the function will iterate again and
+ * again as a result of serving BRPOPLPUSH we can have new blocking clients
+ * to serve because of the PUSH side of BRPOPLPUSH. */
+void handleClientsBlockedOnLists(void) {
+ while(listLength(server.ready_keys) != 0) {
+ list *l;
+
+ /* Point server.ready_keys to a fresh list and save the current one
+ * locally. This way as we run the old list we are free to call
+ * signalListAsReady() that may push new elements in server.ready_keys
+ * when handling clients blocked into BRPOPLPUSH. */
+ l = server.ready_keys;
+ server.ready_keys = listCreate();
+
+ while(listLength(l) != 0) {
+ listNode *ln = listFirst(l);
+ readyList *rl = ln->value;
+
+ /* First of all remove this key from db->ready_keys so that
+ * we can safely call signalListAsReady() against this key. */
+ dictDelete(rl->db->ready_keys,rl->key);
+
+ /* If the key exists and it's a list, serve blocked clients
+ * with data. */
+ robj *o = lookupKeyWrite(rl->db,rl->key);
+ if (o != NULL && o->type == REDIS_LIST) {
+ dictEntry *de;
+
+ /* We serve clients in the same order they blocked for
+ * this key, from the first blocked to the last. */
+ de = dictFind(rl->db->blocking_keys,rl->key);
+ if (de) {
+ list *clients = dictGetVal(de);
+ int numclients = listLength(clients);
+
+ while(numclients--) {
+ listNode *clientnode = listFirst(clients);
+ redisClient *receiver = clientnode->value;
+ robj *dstkey = receiver->bpop.target;
+ int where = (receiver->lastcmd &&
+ receiver->lastcmd->proc == blpopCommand) ?
+ REDIS_HEAD : REDIS_TAIL;
+ robj *value = listTypePop(o,where);
+
+ if (value) {
+ /* Protect receiver->bpop.target, that will be
+ * freed by the next unblockClientWaitingData()
+ * call. */
+ if (dstkey) incrRefCount(dstkey);
+ unblockClientWaitingData(receiver);
+
+ if (serveClientBlockedOnList(receiver,
+ rl->key,dstkey,rl->db,value,
+ where) == REDIS_ERR)
+ {
+ /* If we failed serving the client we need
+ * to also undo the POP operation. */
+ listTypePush(o,value,where);
+ }
+
+ if (dstkey) decrRefCount(dstkey);
+ decrRefCount(value);
+ } else {
+ break;
+ }
+ }
+ }
+
+ if (listTypeLength(o) == 0) dbDelete(rl->db,rl->key);
+ /* We don't call signalModifiedKey() as it was already called
+ * when an element was pushed on the list. */
+ }
+
+ /* Free this item. */
+ decrRefCount(rl->key);
+ zfree(rl);
+ listDelNode(l,ln);
+ }
+ listRelease(l); /* We have the new list on place at this point. */
+ }
+}
+
+int getTimeoutFromObjectOrReply(redisClient *c, robj *object, time_t *timeout) {
+ long tval;
+
+ if (getLongFromObjectOrReply(c,object,&tval,
+ "timeout is not an integer or out of range") != REDIS_OK)
+ return REDIS_ERR;
- de = dictFind(c->db->blocking_keys,key);
- if (de == NULL) return 0;
- l = dictGetEntryVal(de);
- ln = listFirst(l);
- redisAssert(ln != NULL);
- receiver = ln->value;
+ if (tval < 0) {
+ addReplyError(c,"timeout is negative");
+ return REDIS_ERR;
+ }
+
+ if (tval > 0) tval += server.unixtime;
+ *timeout = tval;
- addReplySds(receiver,sdsnew("*2\r\n"));
- addReplyBulk(receiver,key);
- addReplyBulk(receiver,ele);
- unblockClientWaitingData(receiver);
- return 1;
+ return REDIS_OK;
}
/* Blocking RPOP/LPOP */
time_t timeout;
int j;
+ if (getTimeoutFromObjectOrReply(c,c->argv[c->argc-1],&timeout) != REDIS_OK)
+ return;
+
for (j = 1; j < c->argc-1; j++) {
o = lookupKeyWrite(c->db,c->argv[j]);
if (o != NULL) {
return;
} else {
if (listTypeLength(o) != 0) {
- /* If the list contains elements fall back to the usual
- * non-blocking POP operation */
- robj *argv[2], **orig_argv;
- int orig_argc;
-
- /* We need to alter the command arguments before to call
- * popGenericCommand() as the command takes a single key. */
- orig_argv = c->argv;
- orig_argc = c->argc;
- argv[1] = c->argv[j];
- c->argv = argv;
- c->argc = 2;
-
- /* Also the return value is different, we need to output
- * the multi bulk reply header and the key name. The
- * "real" command will add the last element (the value)
- * for us. If this souds like an hack to you it's just
- * because it is... */
- addReplySds(c,sdsnew("*2\r\n"));
- addReplyBulk(c,argv[1]);
- popGenericCommand(c,where);
-
- /* Fix the client structure with the original stuff */
- c->argv = orig_argv;
- c->argc = orig_argc;
+ /* Non empty list, this is like a non normal [LR]POP. */
+ robj *value = listTypePop(o,where);
+ redisAssert(value != NULL);
+
+ addReplyMultiBulkLen(c,2);
+ addReplyBulk(c,c->argv[j]);
+ addReplyBulk(c,value);
+ decrRefCount(value);
+ if (listTypeLength(o) == 0) dbDelete(c->db,c->argv[j]);
+ signalModifiedKey(c->db,c->argv[j]);
+ server.dirty++;
+
+ /* Replicate it as an [LR]POP instead of B[LR]POP. */
+ rewriteClientCommandVector(c,2,
+ (where == REDIS_HEAD) ? shared.lpop : shared.rpop,
+ c->argv[j]);
return;
}
}
}
}
+
+ /* If we are inside a MULTI/EXEC and the list is empty the only thing
+ * we can do is treating it as a timeout (even with timeout 0). */
+ if (c->flags & REDIS_MULTI) {
+ addReply(c,shared.nullmultibulk);
+ return;
+ }
+
/* If the list is empty or the key does not exists we must block */
- timeout = strtol(c->argv[c->argc-1]->ptr,NULL,10);
- if (timeout > 0) timeout += time(NULL);
- blockForKeys(c,c->argv+1,c->argc-2,timeout);
+ blockForKeys(c, c->argv + 1, c->argc - 2, timeout, NULL);
}
void blpopCommand(redisClient *c) {
void brpopCommand(redisClient *c) {
blockingPopGenericCommand(c,REDIS_TAIL);
}
+
+void brpoplpushCommand(redisClient *c) {
+ time_t timeout;
+
+ if (getTimeoutFromObjectOrReply(c,c->argv[3],&timeout) != REDIS_OK)
+ return;
+
+ robj *key = lookupKeyWrite(c->db, c->argv[1]);
+
+ if (key == NULL) {
+ if (c->flags & REDIS_MULTI) {
+ /* Blocking against an empty list in a multi state
+ * returns immediately. */
+ addReply(c, shared.nullbulk);
+ } else {
+ /* The list is empty and the client blocks. */
+ blockForKeys(c, c->argv + 1, 1, timeout, c->argv[2]);
+ }
+ } else {
+ if (key->type != REDIS_LIST) {
+ addReply(c, shared.wrongtypeerr);
+ } else {
+ /* The list exists and has elements, so
+ * the regular rpoplpushCommand is executed. */
+ redisAssertWithInfo(c,key,listTypeLength(key) > 0);
+ rpoplpushCommand(c);
+ }
+ }
+}
projects / redis.git / blobdiff