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Diffstat (limited to 'src/t_list.c')
| -rw-r--r-- | src/t_list.c | 1209 |
1 files changed, 1209 insertions, 0 deletions
diff --git a/src/t_list.c b/src/t_list.c new file mode 100644 index 0000000..705da21 --- /dev/null +++ b/src/t_list.c @@ -0,0 +1,1209 @@ +/* + * 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 "server.h" + +/*----------------------------------------------------------------------------- + * List API + *----------------------------------------------------------------------------*/ + +/* 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; + if (value->encoding == OBJ_ENCODING_INT) { + char buf[32]; + ll2string(buf, 32, (long)value->ptr); + quicklistPush(subject->ptr, buf, strlen(buf), pos); + } else { + quicklistPush(subject->ptr, value->ptr, sdslen(value->ptr), pos); + } + } else { + serverPanic("Unknown list encoding"); + } +} + +void *listPopSaver(unsigned char *data, size_t sz) { + return createStringObject((char*)data,sz); +} + +robj *listTypePop(robj *subject, int where) { + long long vlong; + robj *value = NULL; + + int ql_where = where == LIST_HEAD ? QUICKLIST_HEAD : QUICKLIST_TAIL; + if (subject->encoding == OBJ_ENCODING_QUICKLIST) { + if (quicklistPopCustom(subject->ptr, ql_where, (unsigned char **)&value, + NULL, &vlong, listPopSaver)) { + if (!value) + value = createStringObjectFromLongLong(vlong); + } + } else { + serverPanic("Unknown list encoding"); + } + return value; +} + +unsigned long listTypeLength(const robj *subject) { + if (subject->encoding == OBJ_ENCODING_QUICKLIST) { + return quicklistCount(subject->ptr); + } else { + serverPanic("Unknown list encoding"); + } +} + +/* Initialize an iterator at the specified index. */ +listTypeIterator *listTypeInitIterator(robj *subject, long index, + unsigned char direction) { + listTypeIterator *li = zmalloc(sizeof(listTypeIterator)); + li->subject = subject; + li->encoding = subject->encoding; + li->direction = direction; + li->iter = NULL; + /* LIST_HEAD means start at TAIL and move *towards* head. + * LIST_TAIL means start at HEAD and move *towards tail. */ + int iter_direction = + direction == LIST_HEAD ? AL_START_TAIL : AL_START_HEAD; + if (li->encoding == OBJ_ENCODING_QUICKLIST) { + li->iter = quicklistGetIteratorAtIdx(li->subject->ptr, + iter_direction, index); + } else { + serverPanic("Unknown list encoding"); + } + return li; +} + +/* Sets the direction of an iterator. */ +void listTypeSetIteratorDirection(listTypeIterator *li, unsigned char direction) { + li->direction = direction; + int dir = direction == LIST_HEAD ? AL_START_TAIL : AL_START_HEAD; + quicklistSetDirection(li->iter, dir); +} + +/* Clean up the iterator. */ +void listTypeReleaseIterator(listTypeIterator *li) { + quicklistReleaseIterator(li->iter); + zfree(li); +} + +/* 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; +} + +/* Return entry or NULL at the current position of the iterator. */ +robj *listTypeGet(listTypeEntry *entry) { + robj *value = NULL; + if (entry->li->encoding == OBJ_ENCODING_QUICKLIST) { + if (entry->entry.value) { + value = createStringObject((char *)entry->entry.value, + entry->entry.sz); + } else { + value = createStringObjectFromLongLong(entry->entry.longval); + } + } else { + serverPanic("Unknown list encoding"); + } + return value; +} + +void listTypeInsert(listTypeEntry *entry, robj *value, int where) { + if (entry->li->encoding == OBJ_ENCODING_QUICKLIST) { + value = getDecodedObject(value); + sds str = value->ptr; + size_t len = sdslen(str); + if (where == LIST_TAIL) { + quicklistInsertAfter(entry->li->iter, &entry->entry, str, len); + } else if (where == LIST_HEAD) { + quicklistInsertBefore(entry->li->iter, &entry->entry, str, len); + } + decrRefCount(value); + } else { + serverPanic("Unknown list encoding"); + } +} + +/* Replaces entry at the current position of the iterator. */ +void listTypeReplace(listTypeEntry *entry, robj *value) { + if (entry->li->encoding == OBJ_ENCODING_QUICKLIST) { + value = getDecodedObject(value); + sds str = value->ptr; + size_t len = sdslen(str); + quicklistReplaceEntry(entry->li->iter, &entry->entry, str, len); + decrRefCount(value); + } 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,o->ptr,sdslen(o->ptr)); + } 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"); + } +} + +/* This is a helper function for the COPY command. + * Duplicate a list object, with the guarantee that the returned object + * has the same encoding as the original one. + * + * The resulting object always has refcount set to 1 */ +robj *listTypeDup(robj *o) { + robj *lobj; + + serverAssert(o->type == OBJ_LIST); + + switch (o->encoding) { + case OBJ_ENCODING_QUICKLIST: + lobj = createObject(OBJ_LIST, quicklistDup(o->ptr)); + lobj->encoding = o->encoding; + break; + default: + serverPanic("Unknown list encoding"); + break; + } + return lobj; +} + +/* Delete a range of elements from the list. */ +int listTypeDelRange(robj *subject, long start, long count) { + if (subject->encoding == OBJ_ENCODING_QUICKLIST) { + return quicklistDelRange(subject->ptr, start, count); + } else { + serverPanic("Unknown list encoding"); + } +} + +/*----------------------------------------------------------------------------- + * List Commands + *----------------------------------------------------------------------------*/ + +/* Implements LPUSH/RPUSH/LPUSHX/RPUSHX. + * 'xx': push if key exists. */ +void pushGenericCommand(client *c, int where, int xx) { + int j; + + robj *lobj = lookupKeyWrite(c->db, c->argv[1]); + if (checkType(c,lobj,OBJ_LIST)) return; + if (!lobj) { + if (xx) { + addReply(c, shared.czero); + return; + } + + lobj = createQuicklistObject(); + quicklistSetOptions(lobj->ptr, server.list_max_listpack_size, + server.list_compress_depth); + dbAdd(c->db,c->argv[1],lobj); + } + + for (j = 2; j < c->argc; j++) { + listTypePush(lobj,c->argv[j],where); + server.dirty++; + } + + addReplyLongLong(c, listTypeLength(lobj)); + + char *event = (where == LIST_HEAD) ? "lpush" : "rpush"; + signalModifiedKey(c,c->db,c->argv[1]); + notifyKeyspaceEvent(NOTIFY_LIST,event,c->argv[1],c->db->id); +} + +/* LPUSH <key> <element> [<element> ...] */ +void lpushCommand(client *c) { + pushGenericCommand(c,LIST_HEAD,0); +} + +/* RPUSH <key> <element> [<element> ...] */ +void rpushCommand(client *c) { + pushGenericCommand(c,LIST_TAIL,0); +} + +/* LPUSHX <key> <element> [<element> ...] */ +void lpushxCommand(client *c) { + pushGenericCommand(c,LIST_HEAD,1); +} + +/* RPUSH <key> <element> [<element> ...] */ +void rpushxCommand(client *c) { + pushGenericCommand(c,LIST_TAIL,1); +} + +/* LINSERT <key> (BEFORE|AFTER) <pivot> <element> */ +void linsertCommand(client *c) { + int where; + robj *subject; + listTypeIterator *iter; + listTypeEntry entry; + int inserted = 0; + + if (strcasecmp(c->argv[2]->ptr,"after") == 0) { + where = LIST_TAIL; + } else if (strcasecmp(c->argv[2]->ptr,"before") == 0) { + where = LIST_HEAD; + } else { + addReplyErrorObject(c,shared.syntaxerr); + return; + } + + if ((subject = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL || + checkType(c,subject,OBJ_LIST)) return; + + /* Seek pivot from head to tail */ + iter = listTypeInitIterator(subject,0,LIST_TAIL); + while (listTypeNext(iter,&entry)) { + if (listTypeEqual(&entry,c->argv[3])) { + listTypeInsert(&entry,c->argv[4],where); + inserted = 1; + break; + } + } + listTypeReleaseIterator(iter); + + if (inserted) { + signalModifiedKey(c,c->db,c->argv[1]); + notifyKeyspaceEvent(NOTIFY_LIST,"linsert", + c->argv[1],c->db->id); + server.dirty++; + } else { + /* Notify client of a failed insert */ + addReplyLongLong(c,-1); + return; + } + + addReplyLongLong(c,listTypeLength(subject)); +} + +/* LLEN <key> */ +void llenCommand(client *c) { + robj *o = lookupKeyReadOrReply(c,c->argv[1],shared.czero); + if (o == NULL || checkType(c,o,OBJ_LIST)) return; + addReplyLongLong(c,listTypeLength(o)); +} + +/* LINDEX <key> <index> */ +void lindexCommand(client *c) { + robj *o = lookupKeyReadOrReply(c,c->argv[1],shared.null[c->resp]); + if (o == NULL || checkType(c,o,OBJ_LIST)) return; + long index; + + if ((getLongFromObjectOrReply(c, c->argv[2], &index, NULL) != C_OK)) + return; + + if (o->encoding == OBJ_ENCODING_QUICKLIST) { + quicklistEntry entry; + quicklistIter *iter = quicklistGetIteratorEntryAtIdx(o->ptr, index, &entry); + if (iter) { + if (entry.value) { + addReplyBulkCBuffer(c, entry.value, entry.sz); + } else { + addReplyBulkLongLong(c, entry.longval); + } + } else { + addReplyNull(c); + } + quicklistReleaseIterator(iter); + } else { + serverPanic("Unknown list encoding"); + } +} + +/* LSET <key> <index> <element> */ +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) { + addReplyErrorObject(c,shared.outofrangeerr); + } else { + addReply(c,shared.ok); + signalModifiedKey(c,c->db,c->argv[1]); + notifyKeyspaceEvent(NOTIFY_LIST,"lset",c->argv[1],c->db->id); + server.dirty++; + } + } else { + serverPanic("Unknown list encoding"); + } +} + +/* A helper function like addListRangeReply, more details see below. + * The difference is that here we are returning nested arrays, like: + * 1) keyname + * 2) 1) element1 + * 2) element2 + * + * And also actually pop out from the list by calling listElementsRemoved. + * We maintain the server.dirty and notifications there. + * + * 'deleted' is an optional output argument to get an indication + * if the key got deleted by this function. */ +void listPopRangeAndReplyWithKey(client *c, robj *o, robj *key, int where, long count, int *deleted) { + long llen = listTypeLength(o); + long rangelen = (count > llen) ? llen : count; + long rangestart = (where == LIST_HEAD) ? 0 : -rangelen; + long rangeend = (where == LIST_HEAD) ? rangelen - 1 : -1; + int reverse = (where == LIST_HEAD) ? 0 : 1; + + /* We return key-name just once, and an array of elements */ + addReplyArrayLen(c, 2); + addReplyBulk(c, key); + addListRangeReply(c, o, rangestart, rangeend, reverse); + + /* Pop these elements. */ + listTypeDelRange(o, rangestart, rangelen); + /* Maintain the notifications and dirty. */ + listElementsRemoved(c, key, where, o, rangelen, deleted); +} + +/* A helper for replying with a list's range between the inclusive start and end + * indexes as multi-bulk, with support for negative indexes. Note that start + * must be less than end or an empty array is returned. When the reverse + * argument is set to a non-zero value, the reply is reversed so that elements + * are returned from end to start. */ +void addListRangeReply(client *c, robj *o, long start, long end, int reverse) { + long rangelen, llen = listTypeLength(o); + + /* Convert negative indexes. */ + 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. */ + if (start > end || start >= llen) { + addReply(c,shared.emptyarray); + return; + } + if (end >= llen) end = llen-1; + rangelen = (end-start)+1; + + /* Return the result in form of a multi-bulk reply */ + addReplyArrayLen(c,rangelen); + if (o->encoding == OBJ_ENCODING_QUICKLIST) { + int from = reverse ? end : start; + int direction = reverse ? LIST_HEAD : LIST_TAIL; + listTypeIterator *iter = listTypeInitIterator(o,from,direction); + + while(rangelen--) { + listTypeEntry entry; + serverAssert(listTypeNext(iter, &entry)); /* fail on corrupt data */ + quicklistEntry *qe = &entry.entry; + if (qe->value) { + addReplyBulkCBuffer(c,qe->value,qe->sz); + } else { + addReplyBulkLongLong(c,qe->longval); + } + } + listTypeReleaseIterator(iter); + } else { + serverPanic("Unknown list encoding"); + } +} + +/* A housekeeping helper for list elements popping tasks. + * + * 'deleted' is an optional output argument to get an indication + * if the key got deleted by this function. */ +void listElementsRemoved(client *c, robj *key, int where, robj *o, long count, int *deleted) { + char *event = (where == LIST_HEAD) ? "lpop" : "rpop"; + + notifyKeyspaceEvent(NOTIFY_LIST, event, key, c->db->id); + if (listTypeLength(o) == 0) { + if (deleted) *deleted = 1; + + dbDelete(c->db, key); + notifyKeyspaceEvent(NOTIFY_GENERIC, "del", key, c->db->id); + } else { + if (deleted) *deleted = 0; + } + signalModifiedKey(c, c->db, key); + server.dirty += count; +} + +/* Implements the generic list pop operation for LPOP/RPOP. + * The where argument specifies which end of the list is operated on. An + * optional count may be provided as the third argument of the client's + * command. */ +void popGenericCommand(client *c, int where) { + int hascount = (c->argc == 3); + long count = 0; + robj *value; + + if (c->argc > 3) { + addReplyErrorArity(c); + return; + } else if (hascount) { + /* Parse the optional count argument. */ + if (getPositiveLongFromObjectOrReply(c,c->argv[2],&count,NULL) != C_OK) + return; + } + + robj *o = lookupKeyWriteOrReply(c, c->argv[1], hascount ? shared.nullarray[c->resp]: shared.null[c->resp]); + if (o == NULL || checkType(c, o, OBJ_LIST)) + return; + + if (hascount && !count) { + /* Fast exit path. */ + addReply(c,shared.emptyarray); + return; + } + + if (!count) { + /* Pop a single element. This is POP's original behavior that replies + * with a bulk string. */ + value = listTypePop(o,where); + serverAssert(value != NULL); + addReplyBulk(c,value); + decrRefCount(value); + listElementsRemoved(c,c->argv[1],where,o,1,NULL); + } else { + /* Pop a range of elements. An addition to the original POP command, + * which replies with a multi-bulk. */ + long llen = listTypeLength(o); + long rangelen = (count > llen) ? llen : count; + long rangestart = (where == LIST_HEAD) ? 0 : -rangelen; + long rangeend = (where == LIST_HEAD) ? rangelen - 1 : -1; + int reverse = (where == LIST_HEAD) ? 0 : 1; + + addListRangeReply(c,o,rangestart,rangeend,reverse); + listTypeDelRange(o,rangestart,rangelen); + listElementsRemoved(c,c->argv[1],where,o,rangelen,NULL); + } +} + +/* Like popGenericCommand but work with multiple keys. + * Take multiple keys and return multiple elements from just one key. + * + * 'numkeys' the number of keys. + * 'count' is the number of elements requested to pop. + * + * Always reply with array. */ +void mpopGenericCommand(client *c, robj **keys, int numkeys, int where, long count) { + int j; + robj *o; + robj *key; + + for (j = 0; j < numkeys; j++) { + key = keys[j]; + o = lookupKeyWrite(c->db, key); + + /* Non-existing key, move to next key. */ + if (o == NULL) continue; + + if (checkType(c, o, OBJ_LIST)) return; + + long llen = listTypeLength(o); + /* Empty list, move to next key. */ + if (llen == 0) continue; + + /* Pop a range of elements in a nested arrays way. */ + listPopRangeAndReplyWithKey(c, o, key, where, count, NULL); + + /* Replicate it as [LR]POP COUNT. */ + robj *count_obj = createStringObjectFromLongLong((count > llen) ? llen : count); + rewriteClientCommandVector(c, 3, + (where == LIST_HEAD) ? shared.lpop : shared.rpop, + key, count_obj); + decrRefCount(count_obj); + return; + } + + /* Look like we are not able to pop up any elements. */ + addReplyNullArray(c); +} + +/* LPOP <key> [count] */ +void lpopCommand(client *c) { + popGenericCommand(c,LIST_HEAD); +} + +/* RPOP <key> [count] */ +void rpopCommand(client *c) { + popGenericCommand(c,LIST_TAIL); +} + +/* LRANGE <key> <start> <stop> */ +void lrangeCommand(client *c) { + robj *o; + long start, end; + + if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != C_OK) || + (getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != C_OK)) return; + + if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.emptyarray)) == NULL + || checkType(c,o,OBJ_LIST)) return; + + addListRangeReply(c,o,start,end,0); +} + +/* LTRIM <key> <start> <stop> */ +void ltrimCommand(client *c) { + robj *o; + long start, end, llen, ltrim, rtrim; + + if ((getLongFromObjectOrReply(c, c->argv[2], &start, NULL) != C_OK) || + (getLongFromObjectOrReply(c, c->argv[3], &end, NULL) != C_OK)) return; + + if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.ok)) == NULL || + checkType(c,o,OBJ_LIST)) return; + llen = listTypeLength(o); + + /* convert negative indexes */ + 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. */ + 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; + ltrim = start; + rtrim = llen-end-1; + } + + /* Remove list elements to perform the trim */ + if (o->encoding == OBJ_ENCODING_QUICKLIST) { + quicklistDelRange(o->ptr,0,ltrim); + quicklistDelRange(o->ptr,-rtrim,rtrim); + } else { + serverPanic("Unknown list encoding"); + } + + notifyKeyspaceEvent(NOTIFY_LIST,"ltrim",c->argv[1],c->db->id); + if (listTypeLength(o) == 0) { + dbDelete(c->db,c->argv[1]); + notifyKeyspaceEvent(NOTIFY_GENERIC,"del",c->argv[1],c->db->id); + } + signalModifiedKey(c,c->db,c->argv[1]); + server.dirty += (ltrim + rtrim); + addReply(c,shared.ok); +} + +/* LPOS key element [RANK rank] [COUNT num-matches] [MAXLEN len] + * + * The "rank" is the position of the match, so if it is 1, the first match + * is returned, if it is 2 the second match is returned and so forth. + * It is 1 by default. If negative has the same meaning but the search is + * performed starting from the end of the list. + * + * If COUNT is given, instead of returning the single element, a list of + * all the matching elements up to "num-matches" are returned. COUNT can + * be combined with RANK in order to returning only the element starting + * from the Nth. If COUNT is zero, all the matching elements are returned. + * + * MAXLEN tells the command to scan a max of len elements. If zero (the + * default), all the elements in the list are scanned if needed. + * + * The returned elements indexes are always referring to what LINDEX + * would return. So first element from head is 0, and so forth. */ +void lposCommand(client *c) { + robj *o, *ele; + ele = c->argv[2]; + int direction = LIST_TAIL; + long rank = 1, count = -1, maxlen = 0; /* Count -1: option not given. */ + + /* Parse the optional arguments. */ + for (int j = 3; j < c->argc; j++) { + char *opt = c->argv[j]->ptr; + int moreargs = (c->argc-1)-j; + + if (!strcasecmp(opt,"RANK") && moreargs) { + j++; + if (getLongFromObjectOrReply(c, c->argv[j], &rank, NULL) != C_OK) + return; + if (rank == 0) { + addReplyError(c,"RANK can't be zero: use 1 to start from " + "the first match, 2 from the second ... " + "or use negative to start from the end of the list"); + return; + } + } else if (!strcasecmp(opt,"COUNT") && moreargs) { + j++; + if (getPositiveLongFromObjectOrReply(c, c->argv[j], &count, + "COUNT can't be negative") != C_OK) + return; + } else if (!strcasecmp(opt,"MAXLEN") && moreargs) { + j++; + if (getPositiveLongFromObjectOrReply(c, c->argv[j], &maxlen, + "MAXLEN can't be negative") != C_OK) + return; + } else { + addReplyErrorObject(c,shared.syntaxerr); + return; + } + } + + /* A negative rank means start from the tail. */ + if (rank < 0) { + rank = -rank; + direction = LIST_HEAD; + } + + /* We return NULL or an empty array if there is no such key (or + * if we find no matches, depending on the presence of the COUNT option. */ + if ((o = lookupKeyRead(c->db,c->argv[1])) == NULL) { + if (count != -1) + addReply(c,shared.emptyarray); + else + addReply(c,shared.null[c->resp]); + return; + } + if (checkType(c,o,OBJ_LIST)) return; + + /* If we got the COUNT option, prepare to emit an array. */ + void *arraylenptr = NULL; + if (count != -1) arraylenptr = addReplyDeferredLen(c); + + /* Seek the element. */ + listTypeIterator *li; + li = listTypeInitIterator(o,direction == LIST_HEAD ? -1 : 0,direction); + listTypeEntry entry; + long llen = listTypeLength(o); + long index = 0, matches = 0, matchindex = -1, arraylen = 0; + while (listTypeNext(li,&entry) && (maxlen == 0 || index < maxlen)) { + if (listTypeEqual(&entry,ele)) { + matches++; + matchindex = (direction == LIST_TAIL) ? index : llen - index - 1; + if (matches >= rank) { + if (arraylenptr) { + arraylen++; + addReplyLongLong(c,matchindex); + if (count && matches-rank+1 >= count) break; + } else { + break; + } + } + } + index++; + matchindex = -1; /* Remember if we exit the loop without a match. */ + } + listTypeReleaseIterator(li); + + /* Reply to the client. Note that arraylenptr is not NULL only if + * the COUNT option was selected. */ + if (arraylenptr != NULL) { + setDeferredArrayLen(c,arraylenptr,arraylen); + } else { + if (matchindex != -1) + addReplyLongLong(c,matchindex); + else + addReply(c,shared.null[c->resp]); + } +} + +/* LREM <key> <count> <element> */ +void lremCommand(client *c) { + robj *subject, *obj; + obj = c->argv[3]; + long toremove; + long removed = 0; + + if ((getLongFromObjectOrReply(c, c->argv[2], &toremove, NULL) != C_OK)) + return; + + subject = lookupKeyWriteOrReply(c,c->argv[1],shared.czero); + if (subject == NULL || checkType(c,subject,OBJ_LIST)) return; + + listTypeIterator *li; + if (toremove < 0) { + toremove = -toremove; + li = listTypeInitIterator(subject,-1,LIST_HEAD); + } else { + li = listTypeInitIterator(subject,0,LIST_TAIL); + } + + listTypeEntry entry; + while (listTypeNext(li,&entry)) { + if (listTypeEqual(&entry,obj)) { + listTypeDelete(li, &entry); + server.dirty++; + removed++; + if (toremove && removed == toremove) break; + } + } + listTypeReleaseIterator(li); + + if (removed) { + signalModifiedKey(c,c->db,c->argv[1]); + notifyKeyspaceEvent(NOTIFY_LIST,"lrem",c->argv[1],c->db->id); + } + + if (listTypeLength(subject) == 0) { + dbDelete(c->db,c->argv[1]); + notifyKeyspaceEvent(NOTIFY_GENERIC,"del",c->argv[1],c->db->id); + } + + addReplyLongLong(c,removed); +} + +void lmoveHandlePush(client *c, robj *dstkey, robj *dstobj, robj *value, + int where) { + /* Create the list if the key does not exist */ + if (!dstobj) { + dstobj = createQuicklistObject(); + quicklistSetOptions(dstobj->ptr, server.list_max_listpack_size, + server.list_compress_depth); + dbAdd(c->db,dstkey,dstobj); + } + signalModifiedKey(c,c->db,dstkey); + listTypePush(dstobj,value,where); + notifyKeyspaceEvent(NOTIFY_LIST, + where == LIST_HEAD ? "lpush" : "rpush", + dstkey, + c->db->id); + /* Always send the pushed value to the client. */ + addReplyBulk(c,value); +} + +int getListPositionFromObjectOrReply(client *c, robj *arg, int *position) { + if (strcasecmp(arg->ptr,"right") == 0) { + *position = LIST_TAIL; + } else if (strcasecmp(arg->ptr,"left") == 0) { + *position = LIST_HEAD; + } else { + addReplyErrorObject(c,shared.syntaxerr); + return C_ERR; + } + return C_OK; +} + +robj *getStringObjectFromListPosition(int position) { + if (position == LIST_HEAD) { + return shared.left; + } else { + // LIST_TAIL + return shared.right; + } +} + +void lmoveGenericCommand(client *c, int wherefrom, int whereto) { + robj *sobj, *value; + if ((sobj = lookupKeyWriteOrReply(c,c->argv[1],shared.null[c->resp])) + == NULL || checkType(c,sobj,OBJ_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. */ + addReplyNull(c); + } else { + robj *dobj = lookupKeyWrite(c->db,c->argv[2]); + robj *touchedkey = c->argv[1]; + + if (checkType(c,dobj,OBJ_LIST)) return; + value = listTypePop(sobj,wherefrom); + serverAssert(value); /* assertion for valgrind (avoid NPD) */ + lmoveHandlePush(c,c->argv[2],dobj,value,whereto); + + /* listTypePop returns an object with its refcount incremented */ + decrRefCount(value); + + /* Delete the source list when it is empty */ + notifyKeyspaceEvent(NOTIFY_LIST, + wherefrom == LIST_HEAD ? "lpop" : "rpop", + touchedkey, + c->db->id); + if (listTypeLength(sobj) == 0) { + dbDelete(c->db,touchedkey); + notifyKeyspaceEvent(NOTIFY_GENERIC,"del", + touchedkey,c->db->id); + } + signalModifiedKey(c,c->db,touchedkey); + server.dirty++; + if (c->cmd->proc == blmoveCommand) { + rewriteClientCommandVector(c,5,shared.lmove, + c->argv[1],c->argv[2],c->argv[3],c->argv[4]); + } else if (c->cmd->proc == brpoplpushCommand) { + rewriteClientCommandVector(c,3,shared.rpoplpush, + c->argv[1],c->argv[2]); + } + } +} + +/* LMOVE <source> <destination> (LEFT|RIGHT) (LEFT|RIGHT) */ +void lmoveCommand(client *c) { + int wherefrom, whereto; + if (getListPositionFromObjectOrReply(c,c->argv[3],&wherefrom) + != C_OK) return; + if (getListPositionFromObjectOrReply(c,c->argv[4],&whereto) + != C_OK) return; + lmoveGenericCommand(c, wherefrom, whereto); +} + +/* 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 + * 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(client *c) { + lmoveGenericCommand(c, LIST_TAIL, LIST_HEAD); +} + +/*----------------------------------------------------------------------------- + * Blocking POP operations + *----------------------------------------------------------------------------*/ + +/* This is a helper function for handleClientsBlockedOnKeys(). Its work + * is to serve a specific client (receiver) that is blocked on 'key' + * in the context of the specified 'db', doing the following: + * + * 1) Provide the client with the 'value' element or a range of elements. + * We will do the pop in here and caller does not need to bother the return. + * 2) If the dstkey is not NULL (we are serving a BLMOVE) also push the + * 'value' element on the destination list (the "push" side of the command). + * 3) Propagate the resulting BRPOP, BLPOP, BLMPOP and additional xPUSH if any into + * the AOF and replication channel. + * + * The argument 'wherefrom' is LIST_TAIL or LIST_HEAD, and indicates if the + * 'value' element was popped from the head (BLPOP) or tail (BRPOP) so that + * we can propagate the command properly. + * + * The argument 'whereto' is LIST_TAIL or LIST_HEAD, and indicates if the + * 'value' element is to be pushed to the head or tail so that we can + * propagate the command properly. + * + * 'deleted' is an optional output argument to get an indication + * if the key got deleted by this function. */ +void serveClientBlockedOnList(client *receiver, robj *o, robj *key, robj *dstkey, redisDb *db, int wherefrom, int whereto, int *deleted) +{ + robj *argv[5]; + robj *value = NULL; + + if (deleted) *deleted = 0; + + if (dstkey == NULL) { + /* Propagate the [LR]POP operation. */ + argv[0] = (wherefrom == LIST_HEAD) ? shared.lpop : + shared.rpop; + argv[1] = key; + + if (receiver->lastcmd->proc == blmpopCommand) { + /* Propagate the [LR]POP COUNT operation. */ + long count = receiver->bpop.count; + serverAssert(count > 0); + long llen = listTypeLength(o); + serverAssert(llen > 0); + + argv[2] = createStringObjectFromLongLong((count > llen) ? llen : count); + alsoPropagate(db->id, argv, 3, PROPAGATE_AOF|PROPAGATE_REPL); + decrRefCount(argv[2]); + + /* Pop a range of elements in a nested arrays way. */ + listPopRangeAndReplyWithKey(receiver, o, key, wherefrom, count, deleted); + return; + } + + alsoPropagate(db->id, argv, 2, PROPAGATE_AOF|PROPAGATE_REPL); + + /* BRPOP/BLPOP */ + value = listTypePop(o, wherefrom); + serverAssert(value != NULL); + + addReplyArrayLen(receiver,2); + addReplyBulk(receiver,key); + addReplyBulk(receiver,value); + + /* Notify event. */ + char *event = (wherefrom == LIST_HEAD) ? "lpop" : "rpop"; + notifyKeyspaceEvent(NOTIFY_LIST,event,key,receiver->db->id); + } else { + /* BLMOVE */ + robj *dstobj = + lookupKeyWrite(receiver->db,dstkey); + if (!(dstobj && + checkType(receiver,dstobj,OBJ_LIST))) + { + value = listTypePop(o, wherefrom); + serverAssert(value != NULL); + + lmoveHandlePush(receiver,dstkey,dstobj,value,whereto); + /* Propagate the LMOVE/RPOPLPUSH operation. */ + int isbrpoplpush = (receiver->lastcmd->proc == brpoplpushCommand); + argv[0] = isbrpoplpush ? shared.rpoplpush : shared.lmove; + argv[1] = key; + argv[2] = dstkey; + argv[3] = getStringObjectFromListPosition(wherefrom); + argv[4] = getStringObjectFromListPosition(whereto); + alsoPropagate(db->id,argv,(isbrpoplpush ? 3 : 5),PROPAGATE_AOF|PROPAGATE_REPL); + + /* Notify event ("lpush" or "rpush" was notified by lmoveHandlePush). */ + notifyKeyspaceEvent(NOTIFY_LIST,wherefrom == LIST_TAIL ? "rpop" : "lpop", + key,receiver->db->id); + } + } + + if (value) decrRefCount(value); + + if (listTypeLength(o) == 0) { + if (deleted) *deleted = 1; + + dbDelete(receiver->db, key); + notifyKeyspaceEvent(NOTIFY_GENERIC, "del", key, receiver->db->id); + } + /* We don't call signalModifiedKey() as it was already called + * when an element was pushed on the list. */ +} + +/* Blocking RPOP/LPOP/LMPOP + * + * 'numkeys' is the number of keys. + * 'timeout_idx' parameter position of block timeout. + * 'where' LIST_HEAD for LEFT, LIST_TAIL for RIGHT. + * 'count' is the number of elements requested to pop, or -1 for plain single pop. + * + * When count is -1, a reply of a single bulk-string will be used. + * When count > 0, an array reply will be used. */ +void blockingPopGenericCommand(client *c, robj **keys, int numkeys, int where, int timeout_idx, long count) { + robj *o; + robj *key; + mstime_t timeout; + int j; + + if (getTimeoutFromObjectOrReply(c,c->argv[timeout_idx],&timeout,UNIT_SECONDS) + != C_OK) return; + + /* Traverse all input keys, we take action only based on one key. */ + for (j = 0; j < numkeys; j++) { + key = keys[j]; + o = lookupKeyWrite(c->db, key); + + /* Non-existing key, move to next key. */ + if (o == NULL) continue; + + if (checkType(c, o, OBJ_LIST)) return; + + long llen = listTypeLength(o); + /* Empty list, move to next key. */ + if (llen == 0) continue; + + if (count != -1) { + /* BLMPOP, non empty list, like a normal [LR]POP with count option. + * The difference here we pop a range of elements in a nested arrays way. */ + listPopRangeAndReplyWithKey(c, o, key, where, count, NULL); + + /* Replicate it as [LR]POP COUNT. */ + robj *count_obj = createStringObjectFromLongLong((count > llen) ? llen : count); + rewriteClientCommandVector(c, 3, + (where == LIST_HEAD) ? shared.lpop : shared.rpop, + key, count_obj); + decrRefCount(count_obj); + return; + } + + /* Non empty list, this is like a normal [LR]POP. */ + robj *value = listTypePop(o,where); + serverAssert(value != NULL); + + addReplyArrayLen(c,2); + addReplyBulk(c,key); + addReplyBulk(c,value); + decrRefCount(value); + listElementsRemoved(c,key,where,o,1,NULL); + + /* Replicate it as an [LR]POP instead of B[LR]POP. */ + rewriteClientCommandVector(c,2, + (where == LIST_HEAD) ? shared.lpop : shared.rpop, + key); + return; + } + + /* If we are not allowed to block the client, the only thing + * we can do is treating it as a timeout (even with timeout 0). */ + if (c->flags & CLIENT_DENY_BLOCKING) { + addReplyNullArray(c); + return; + } + + /* If the keys do not exist we must block */ + struct blockPos pos = {where}; + blockForKeys(c,BLOCKED_LIST,keys,numkeys,count,timeout,NULL,&pos,NULL); +} + +/* BLPOP <key> [<key> ...] <timeout> */ +void blpopCommand(client *c) { + blockingPopGenericCommand(c,c->argv+1,c->argc-2,LIST_HEAD,c->argc-1,-1); +} + +/* BRPOP <key> [<key> ...] <timeout> */ +void brpopCommand(client *c) { + blockingPopGenericCommand(c,c->argv+1,c->argc-2,LIST_TAIL,c->argc-1,-1); +} + +void blmoveGenericCommand(client *c, int wherefrom, int whereto, mstime_t timeout) { + robj *key = lookupKeyWrite(c->db, c->argv[1]); + if (checkType(c,key,OBJ_LIST)) return; + + if (key == NULL) { + if (c->flags & CLIENT_DENY_BLOCKING) { + /* Blocking against an empty list when blocking is not allowed + * returns immediately. */ + addReplyNull(c); + } else { + /* The list is empty and the client blocks. */ + struct blockPos pos = {wherefrom, whereto}; + blockForKeys(c,BLOCKED_LIST,c->argv + 1,1,-1,timeout,c->argv[2],&pos,NULL); + } + } else { + /* The list exists and has elements, so + * the regular lmoveCommand is executed. */ + serverAssertWithInfo(c,key,listTypeLength(key) > 0); + lmoveGenericCommand(c,wherefrom,whereto); + } +} + +/* BLMOVE <source> <destination> (LEFT|RIGHT) (LEFT|RIGHT) <timeout> */ +void blmoveCommand(client *c) { + mstime_t timeout; + int wherefrom, whereto; + if (getListPositionFromObjectOrReply(c,c->argv[3],&wherefrom) + != C_OK) return; + if (getListPositionFromObjectOrReply(c,c->argv[4],&whereto) + != C_OK) return; + if (getTimeoutFromObjectOrReply(c,c->argv[5],&timeout,UNIT_SECONDS) + != C_OK) return; + blmoveGenericCommand(c,wherefrom,whereto,timeout); +} + +/* BRPOPLPUSH <source> <destination> <timeout> */ +void brpoplpushCommand(client *c) { + mstime_t timeout; + if (getTimeoutFromObjectOrReply(c,c->argv[3],&timeout,UNIT_SECONDS) + != C_OK) return; + blmoveGenericCommand(c, LIST_TAIL, LIST_HEAD, timeout); +} + +/* LMPOP/BLMPOP + * + * 'numkeys_idx' parameter position of key number. + * 'is_block' this indicates whether it is a blocking variant. */ +void lmpopGenericCommand(client *c, int numkeys_idx, int is_block) { + long j; + long numkeys = 0; /* Number of keys. */ + int where = 0; /* HEAD for LEFT, TAIL for RIGHT. */ + long count = -1; /* Reply will consist of up to count elements, depending on the list's length. */ + + /* Parse the numkeys. */ + if (getRangeLongFromObjectOrReply(c, c->argv[numkeys_idx], 1, LONG_MAX, + &numkeys, "numkeys should be greater than 0") != C_OK) + return; + + /* Parse the where. where_idx: the index of where in the c->argv. */ + long where_idx = numkeys_idx + numkeys + 1; + if (where_idx >= c->argc) { + addReplyErrorObject(c, shared.syntaxerr); + return; + } + if (getListPositionFromObjectOrReply(c, c->argv[where_idx], &where) != C_OK) + return; + + /* Parse the optional arguments. */ + for (j = where_idx + 1; j < c->argc; j++) { + char *opt = c->argv[j]->ptr; + int moreargs = (c->argc - 1) - j; + + if (count == -1 && !strcasecmp(opt, "COUNT") && moreargs) { + j++; + if (getRangeLongFromObjectOrReply(c, c->argv[j], 1, LONG_MAX, + &count,"count should be greater than 0") != C_OK) + return; + } else { + addReplyErrorObject(c, shared.syntaxerr); + return; + } + } + + if (count == -1) count = 1; + + if (is_block) { + /* BLOCK. We will handle CLIENT_DENY_BLOCKING flag in blockingPopGenericCommand. */ + blockingPopGenericCommand(c, c->argv+numkeys_idx+1, numkeys, where, 1, count); + } else { + /* NON-BLOCK */ + mpopGenericCommand(c, c->argv+numkeys_idx+1, numkeys, where, count); + } +} + +/* LMPOP numkeys <key> [<key> ...] (LEFT|RIGHT) [COUNT count] */ +void lmpopCommand(client *c) { + lmpopGenericCommand(c, 1, 0); +} + +/* BLMPOP timeout numkeys <key> [<key> ...] (LEFT|RIGHT) [COUNT count] */ +void blmpopCommand(client *c) { + lmpopGenericCommand(c, 2, 1); +} |