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redis/src/t_stream.c

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/*
* Copyright (c) 2017-Present, Redis Ltd.
* All rights reserved.
*
* Licensed under your choice of the Redis Source Available License 2.0
* (RSALv2) or the Server Side Public License v1 (SSPLv1).
*/
#include "server.h"
#include "endianconv.h"
#include "stream.h"
/* Every stream item inside the listpack, has a flags field that is used to
* mark the entry as deleted, or having the same field as the "master"
* entry at the start of the listpack> */
#define STREAM_ITEM_FLAG_NONE 0 /* No special flags. */
#define STREAM_ITEM_FLAG_DELETED (1<<0) /* Entry is deleted. Skip it. */
#define STREAM_ITEM_FLAG_SAMEFIELDS (1<<1) /* Same fields as master entry. */
/* For stream commands that require multiple IDs
* when the number of IDs is less than 'STREAMID_STATIC_VECTOR_LEN',
* avoid malloc allocation.*/
#define STREAMID_STATIC_VECTOR_LEN 8
/* Max pre-allocation for listpack. This is done to avoid abuse of a user
* setting stream_node_max_bytes to a huge number. */
#define STREAM_LISTPACK_MAX_PRE_ALLOCATE 4096
/* Don't let listpacks grow too big, even if the user config allows it.
* doing so can lead to an overflow (trying to store more than 32bit length
* into the listpack header), or actually an assertion since lpInsert
* will return NULL. */
#define STREAM_LISTPACK_MAX_SIZE (1<<30)
void streamFreeCG(streamCG *cg);
void streamFreeNACK(streamNACK *na);
size_t streamReplyWithRangeFromConsumerPEL(client *c, stream *s, streamID *start, streamID *end, size_t count, streamConsumer *consumer);
int streamParseStrictIDOrReply(client *c, robj *o, streamID *id, uint64_t missing_seq, int *seq_given);
int streamParseIDOrReply(client *c, robj *o, streamID *id, uint64_t missing_seq);
/* -----------------------------------------------------------------------
* Low level stream encoding: a radix tree of listpacks.
* ----------------------------------------------------------------------- */
/* Create a new stream data structure. */
stream *streamNew(void) {
stream *s = zmalloc(sizeof(*s));
s->rax = raxNew();
s->length = 0;
s->first_id.ms = 0;
s->first_id.seq = 0;
s->last_id.ms = 0;
s->last_id.seq = 0;
s->max_deleted_entry_id.seq = 0;
s->max_deleted_entry_id.ms = 0;
s->entries_added = 0;
s->cgroups = NULL; /* Created on demand to save memory when not used. */
return s;
}
/* Free a stream, including the listpacks stored inside the radix tree. */
void freeStream(stream *s) {
raxFreeWithCallback(s->rax,(void(*)(void*))lpFree);
if (s->cgroups)
raxFreeWithCallback(s->cgroups,(void(*)(void*))streamFreeCG);
zfree(s);
}
/* Return the length of a stream. */
unsigned long streamLength(const robj *subject) {
stream *s = subject->ptr;
return s->length;
}
/* Set 'id' to be its successor stream ID.
* If 'id' is the maximal possible id, it is wrapped around to 0-0 and a
* C_ERR is returned. */
int streamIncrID(streamID *id) {
int ret = C_OK;
if (id->seq == UINT64_MAX) {
if (id->ms == UINT64_MAX) {
/* Special case where 'id' is the last possible streamID... */
id->ms = id->seq = 0;
ret = C_ERR;
} else {
id->ms++;
id->seq = 0;
}
} else {
id->seq++;
}
return ret;
}
/* Set 'id' to be its predecessor stream ID.
* If 'id' is the minimal possible id, it remains 0-0 and a C_ERR is
* returned. */
int streamDecrID(streamID *id) {
int ret = C_OK;
if (id->seq == 0) {
if (id->ms == 0) {
/* Special case where 'id' is the first possible streamID... */
id->ms = id->seq = UINT64_MAX;
ret = C_ERR;
} else {
id->ms--;
id->seq = UINT64_MAX;
}
} else {
id->seq--;
}
return ret;
}
/* Generate the next stream item ID given the previous one. If the current
* milliseconds Unix time is greater than the previous one, just use this
* as time part and start with sequence part of zero. Otherwise we use the
* previous time (and never go backward) and increment the sequence. */
void streamNextID(streamID *last_id, streamID *new_id) {
uint64_t ms = commandTimeSnapshot();
if (ms > last_id->ms) {
new_id->ms = ms;
new_id->seq = 0;
} else {
*new_id = *last_id;
streamIncrID(new_id);
}
}
/* This is a helper function for the COPY command.
* Duplicate a Stream 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 *streamDup(robj *o) {
robj *sobj;
serverAssert(o->type == OBJ_STREAM);
switch (o->encoding) {
case OBJ_ENCODING_STREAM:
sobj = createStreamObject();
break;
default:
serverPanic("Wrong encoding.");
break;
}
stream *s;
stream *new_s;
s = o->ptr;
new_s = sobj->ptr;
raxIterator ri;
uint64_t rax_key[2];
raxStart(&ri, s->rax);
raxSeek(&ri, "^", NULL, 0);
size_t lp_bytes = 0; /* Total bytes in the listpack. */
unsigned char *lp = NULL; /* listpack pointer. */
/* Get a reference to the listpack node. */
while (raxNext(&ri)) {
lp = ri.data;
lp_bytes = lpBytes(lp);
unsigned char *new_lp = zmalloc(lp_bytes);
memcpy(new_lp, lp, lp_bytes);
memcpy(rax_key, ri.key, sizeof(rax_key));
raxInsert(new_s->rax, (unsigned char *)&rax_key, sizeof(rax_key),
new_lp, NULL);
}
new_s->length = s->length;
new_s->first_id = s->first_id;
new_s->last_id = s->last_id;
new_s->max_deleted_entry_id = s->max_deleted_entry_id;
new_s->entries_added = s->entries_added;
raxStop(&ri);
if (s->cgroups == NULL) return sobj;
/* Consumer Groups */
raxIterator ri_cgroups;
raxStart(&ri_cgroups, s->cgroups);
raxSeek(&ri_cgroups, "^", NULL, 0);
while (raxNext(&ri_cgroups)) {
streamCG *cg = ri_cgroups.data;
streamCG *new_cg = streamCreateCG(new_s, (char *)ri_cgroups.key,
ri_cgroups.key_len, &cg->last_id,
cg->entries_read);
serverAssert(new_cg != NULL);
/* Consumer Group PEL */
raxIterator ri_cg_pel;
raxStart(&ri_cg_pel,cg->pel);
raxSeek(&ri_cg_pel,"^",NULL,0);
while(raxNext(&ri_cg_pel)){
streamNACK *nack = ri_cg_pel.data;
streamNACK *new_nack = streamCreateNACK(NULL);
new_nack->delivery_time = nack->delivery_time;
new_nack->delivery_count = nack->delivery_count;
raxInsert(new_cg->pel, ri_cg_pel.key, sizeof(streamID), new_nack, NULL);
}
raxStop(&ri_cg_pel);
/* Consumers */
raxIterator ri_consumers;
raxStart(&ri_consumers, cg->consumers);
raxSeek(&ri_consumers, "^", NULL, 0);
while (raxNext(&ri_consumers)) {
streamConsumer *consumer = ri_consumers.data;
streamConsumer *new_consumer;
new_consumer = zmalloc(sizeof(*new_consumer));
new_consumer->name = sdsdup(consumer->name);
new_consumer->pel = raxNew();
raxInsert(new_cg->consumers,(unsigned char *)new_consumer->name,
sdslen(new_consumer->name), new_consumer, NULL);
new_consumer->seen_time = consumer->seen_time;
new_consumer->active_time = consumer->active_time;
/* Consumer PEL */
raxIterator ri_cpel;
raxStart(&ri_cpel, consumer->pel);
raxSeek(&ri_cpel, "^", NULL, 0);
while (raxNext(&ri_cpel)) {
void *result;
int found = raxFind(new_cg->pel,ri_cpel.key,sizeof(streamID),&result);
serverAssert(found);
streamNACK *new_nack = result;
new_nack->consumer = new_consumer;
raxInsert(new_consumer->pel,ri_cpel.key,sizeof(streamID),new_nack,NULL);
}
raxStop(&ri_cpel);
}
raxStop(&ri_consumers);
}
raxStop(&ri_cgroups);
return sobj;
}
/* This is a wrapper function for lpGet() to directly get an integer value
* from the listpack (that may store numbers as a string), converting
* the string if needed.
* The 'valid" argument is an optional output parameter to get an indication
* if the record was valid, when this parameter is NULL, the function will
* fail with an assertion. */
static inline int64_t lpGetIntegerIfValid(unsigned char *ele, int *valid) {
int64_t v;
unsigned char *e = lpGet(ele,&v,NULL);
if (e == NULL) {
if (valid)
*valid = 1;
return v;
}
/* The following code path should never be used for how listpacks work:
* they should always be able to store an int64_t value in integer
* encoded form. However the implementation may change. */
long long ll;
int ret = string2ll((char*)e,v,&ll);
if (valid)
*valid = ret;
else
serverAssert(ret != 0);
v = ll;
return v;
}
#define lpGetInteger(ele) lpGetIntegerIfValid(ele, NULL)
/* Get an edge streamID of a given listpack.
* 'master_id' is an input param, used to build the 'edge_id' output param */
int lpGetEdgeStreamID(unsigned char *lp, int first, streamID *master_id, streamID *edge_id)
{
if (lp == NULL)
return 0;
unsigned char *lp_ele;
/* We need to seek either the first or the last entry depending
* on the direction of the iteration. */
if (first) {
/* Get the master fields count. */
lp_ele = lpFirst(lp); /* Seek items count */
lp_ele = lpNext(lp, lp_ele); /* Seek deleted count. */
lp_ele = lpNext(lp, lp_ele); /* Seek num fields. */
int64_t master_fields_count = lpGetInteger(lp_ele);
lp_ele = lpNext(lp, lp_ele); /* Seek first field. */
/* If we are iterating in normal order, skip the master fields
* to seek the first actual entry. */
for (int64_t i = 0; i < master_fields_count; i++)
lp_ele = lpNext(lp, lp_ele);
/* If we are going forward, skip the previous entry's
* lp-count field (or in case of the master entry, the zero
* term field) */
lp_ele = lpNext(lp, lp_ele);
if (lp_ele == NULL)
return 0;
} else {
/* If we are iterating in reverse direction, just seek the
* last part of the last entry in the listpack (that is, the
* fields count). */
lp_ele = lpLast(lp);
/* If we are going backward, read the number of elements this
* entry is composed of, and jump backward N times to seek
* its start. */
int64_t lp_count = lpGetInteger(lp_ele);
if (lp_count == 0) /* We reached the master entry. */
return 0;
while (lp_count--)
lp_ele = lpPrev(lp, lp_ele);
}
lp_ele = lpNext(lp, lp_ele); /* Seek ID (lp_ele currently points to 'flags'). */
/* Get the ID: it is encoded as difference between the master
* ID and this entry ID. */
streamID id = *master_id;
id.ms += lpGetInteger(lp_ele);
lp_ele = lpNext(lp, lp_ele);
id.seq += lpGetInteger(lp_ele);
*edge_id = id;
return 1;
}
/* Debugging function to log the full content of a listpack. Useful
* for development and debugging. */
void streamLogListpackContent(unsigned char *lp) {
unsigned char *p = lpFirst(lp);
while(p) {
unsigned char buf[LP_INTBUF_SIZE];
int64_t v;
unsigned char *ele = lpGet(p,&v,buf);
serverLog(LL_WARNING,"- [%d] '%.*s'", (int)v, (int)v, ele);
p = lpNext(lp,p);
}
}
/* Convert the specified stream entry ID as a 128 bit big endian number, so
* that the IDs can be sorted lexicographically. */
void streamEncodeID(void *buf, streamID *id) {
uint64_t e[2];
e[0] = htonu64(id->ms);
e[1] = htonu64(id->seq);
memcpy(buf,e,sizeof(e));
}
/* This is the reverse of streamEncodeID(): the decoded ID will be stored
* in the 'id' structure passed by reference. The buffer 'buf' must point
* to a 128 bit big-endian encoded ID. */
void streamDecodeID(void *buf, streamID *id) {
uint64_t e[2];
memcpy(e,buf,sizeof(e));
id->ms = ntohu64(e[0]);
id->seq = ntohu64(e[1]);
}
/* Compare two stream IDs. Return -1 if a < b, 0 if a == b, 1 if a > b. */
int streamCompareID(streamID *a, streamID *b) {
if (a->ms > b->ms) return 1;
else if (a->ms < b->ms) return -1;
/* The ms part is the same. Check the sequence part. */
else if (a->seq > b->seq) return 1;
else if (a->seq < b->seq) return -1;
/* Everything is the same: IDs are equal. */
return 0;
}
/* Retrieves the ID of the stream edge entry. An edge is either the first or
* the last ID in the stream, and may be a tombstone. To filter out tombstones,
* set the'skip_tombstones' argument to 1. */
void streamGetEdgeID(stream *s, int first, int skip_tombstones, streamID *edge_id)
{
streamIterator si;
int64_t numfields;
streamIteratorStart(&si,s,NULL,NULL,!first);
si.skip_tombstones = skip_tombstones;
int found = streamIteratorGetID(&si,edge_id,&numfields);
if (!found) {
streamID min_id = {0, 0}, max_id = {UINT64_MAX, UINT64_MAX};
*edge_id = first ? max_id : min_id;
}
streamIteratorStop(&si);
}
/* Adds a new item into the stream 's' having the specified number of
* field-value pairs as specified in 'numfields' and stored into 'argv'.
* Returns the new entry ID populating the 'added_id' structure.
*
* If 'use_id' is not NULL, the ID is not auto-generated by the function,
* but instead the passed ID is used to add the new entry. In this case
* adding the entry may fail as specified later in this comment.
*
* When 'use_id' is used alongside with a zero 'seq-given', the sequence
* part of the passed ID is ignored and the function will attempt to use an
* auto-generated sequence.
*
* The function returns C_OK if the item was added, this is always true
* if the ID was generated by the function. However the function may return
* C_ERR in several cases:
* 1. If an ID was given via 'use_id', but adding it failed since the
* current top ID is greater or equal. errno will be set to EDOM.
* 2. If a size of a single element or the sum of the elements is too big to
* be stored into the stream. errno will be set to ERANGE. */
int streamAppendItem(stream *s, robj **argv, int64_t numfields, streamID *added_id, streamID *use_id, int seq_given) {
/* Generate the new entry ID. */
streamID id;
if (use_id) {
if (seq_given) {
id = *use_id;
} else {
/* The automatically generated sequence can be either zero (new
* timestamps) or the incremented sequence of the last ID. In the
* latter case, we need to prevent an overflow/advancing forward
* in time. */
if (s->last_id.ms == use_id->ms) {
if (s->last_id.seq == UINT64_MAX) {
errno = EDOM;
return C_ERR;
}
id = s->last_id;
id.seq++;
} else {
id = *use_id;
}
}
} else {
streamNextID(&s->last_id,&id);
}
/* Check that the new ID is greater than the last entry ID
* or return an error. Automatically generated IDs might
* overflow (and wrap-around) when incrementing the sequence
part. */
if (streamCompareID(&id,&s->last_id) <= 0) {
errno = EDOM;
return C_ERR;
}
/* Avoid overflow when trying to add an element to the stream (listpack
* can only host up to 32bit length strings, and also a total listpack size
* can't be bigger than 32bit length. */
size_t totelelen = 0;
for (int64_t i = 0; i < numfields*2; i++) {
sds ele = argv[i]->ptr;
totelelen += sdslen(ele);
}
if (totelelen > STREAM_LISTPACK_MAX_SIZE) {
errno = ERANGE;
return C_ERR;
}
/* Add the new entry. */
raxIterator ri;
raxStart(&ri,s->rax);
raxSeek(&ri,"$",NULL,0);
size_t lp_bytes = 0; /* Total bytes in the tail listpack. */
unsigned char *lp = NULL; /* Tail listpack pointer. */
if (!raxEOF(&ri)) {
/* Get a reference to the tail node listpack. */
lp = ri.data;
lp_bytes = lpBytes(lp);
}
raxStop(&ri);
/* We have to add the key into the radix tree in lexicographic order,
* to do so we consider the ID as a single 128 bit number written in
* big endian, so that the most significant bytes are the first ones. */
uint64_t rax_key[2]; /* Key in the radix tree containing the listpack.*/
streamID master_id; /* ID of the master entry in the listpack. */
/* Create a new listpack and radix tree node if needed. Note that when
* a new listpack is created, we populate it with a "master entry". This
* is just a set of fields that is taken as references in order to compress
* the stream entries that we'll add inside the listpack.
*
* Note that while we use the first added entry fields to create
* the master entry, the first added entry is NOT represented in the master
* entry, which is a stand alone object. But of course, the first entry
* will compress well because it's used as reference.
*
* The master entry is composed like in the following example:
*
* +-------+---------+------------+---------+--/--+---------+---------+-+
* | count | deleted | num-fields | field_1 | field_2 | ... | field_N |0|
* +-------+---------+------------+---------+--/--+---------+---------+-+
*
* count and deleted just represent respectively the total number of
* entries inside the listpack that are valid, and marked as deleted
* (deleted flag in the entry flags set). So the total number of items
* actually inside the listpack (both deleted and not) is count+deleted.
*
* The real entries will be encoded with an ID that is just the
* millisecond and sequence difference compared to the key stored at
* the radix tree node containing the listpack (delta encoding), and
* if the fields of the entry are the same as the master entry fields, the
* entry flags will specify this fact and the entry fields and number
* of fields will be omitted (see later in the code of this function).
*
* The "0" entry at the end is the same as the 'lp-count' entry in the
* regular stream entries (see below), and marks the fact that there are
* no more entries, when we scan the stream from right to left. */
/* First of all, check if we can append to the current macro node or
* if we need to switch to the next one. 'lp' will be set to NULL if
* the current node is full. */
if (lp != NULL) {
int new_node = 0;
size_t node_max_bytes = server.stream_node_max_bytes;
if (node_max_bytes == 0 || node_max_bytes > STREAM_LISTPACK_MAX_SIZE)
node_max_bytes = STREAM_LISTPACK_MAX_SIZE;
if (lp_bytes + totelelen >= node_max_bytes) {
new_node = 1;
} else if (server.stream_node_max_entries) {
unsigned char *lp_ele = lpFirst(lp);
/* Count both live entries and deleted ones. */
int64_t count = lpGetInteger(lp_ele) + lpGetInteger(lpNext(lp,lp_ele));
if (count >= server.stream_node_max_entries) new_node = 1;
}
if (new_node) {
/* Shrink extra pre-allocated memory */
lp = lpShrinkToFit(lp);
if (ri.data != lp)
raxInsert(s->rax,ri.key,ri.key_len,lp,NULL);
lp = NULL;
}
}
int flags = STREAM_ITEM_FLAG_NONE;
if (lp == NULL) {
master_id = id;
streamEncodeID(rax_key,&id);
/* Create the listpack having the master entry ID and fields.
* Pre-allocate some bytes when creating listpack to avoid realloc on
* every XADD. Since listpack.c uses malloc_size, it'll grow in steps,
* and won't realloc on every XADD.
* When listpack reaches max number of entries, we'll shrink the
* allocation to fit the data. */
size_t prealloc = STREAM_LISTPACK_MAX_PRE_ALLOCATE;
if (server.stream_node_max_bytes > 0 && server.stream_node_max_bytes < prealloc) {
prealloc = server.stream_node_max_bytes;
}
lp = lpNew(prealloc);
lp = lpAppendInteger(lp,1); /* One item, the one we are adding. */
lp = lpAppendInteger(lp,0); /* Zero deleted so far. */
lp = lpAppendInteger(lp,numfields);
for (int64_t i = 0; i < numfields; i++) {
sds field = argv[i*2]->ptr;
lp = lpAppend(lp,(unsigned char*)field,sdslen(field));
}
lp = lpAppendInteger(lp,0); /* Master entry zero terminator. */
raxInsert(s->rax,(unsigned char*)&rax_key,sizeof(rax_key),lp,NULL);
/* The first entry we insert, has obviously the same fields of the
* master entry. */
flags |= STREAM_ITEM_FLAG_SAMEFIELDS;
} else {
serverAssert(ri.key_len == sizeof(rax_key));
memcpy(rax_key,ri.key,sizeof(rax_key));
/* Read the master ID from the radix tree key. */
streamDecodeID(rax_key,&master_id);
unsigned char *lp_ele = lpFirst(lp);
/* Update count and skip the deleted fields. */
int64_t count = lpGetInteger(lp_ele);
lp = lpReplaceInteger(lp,&lp_ele,count+1);
lp_ele = lpNext(lp,lp_ele); /* seek deleted. */
lp_ele = lpNext(lp,lp_ele); /* seek master entry num fields. */
/* Check if the entry we are adding, have the same fields
* as the master entry. */
int64_t master_fields_count = lpGetInteger(lp_ele);
lp_ele = lpNext(lp,lp_ele);
if (numfields == master_fields_count) {
int64_t i;
for (i = 0; i < master_fields_count; i++) {
sds field = argv[i*2]->ptr;
int64_t e_len;
unsigned char buf[LP_INTBUF_SIZE];
unsigned char *e = lpGet(lp_ele,&e_len,buf);
/* Stop if there is a mismatch. */
if (sdslen(field) != (size_t)e_len ||
memcmp(e,field,e_len) != 0) break;
lp_ele = lpNext(lp,lp_ele);
}
/* All fields are the same! We can compress the field names
* setting a single bit in the flags. */
if (i == master_fields_count) flags |= STREAM_ITEM_FLAG_SAMEFIELDS;
}
}
/* Populate the listpack with the new entry. We use the following
* encoding:
*
* +-----+--------+----------+-------+-------+-/-+-------+-------+--------+
* |flags|entry-id|num-fields|field-1|value-1|...|field-N|value-N|lp-count|
* +-----+--------+----------+-------+-------+-/-+-------+-------+--------+
*
* However if the SAMEFIELD flag is set, we have just to populate
* the entry with the values, so it becomes:
*
* +-----+--------+-------+-/-+-------+--------+
* |flags|entry-id|value-1|...|value-N|lp-count|
* +-----+--------+-------+-/-+-------+--------+
*
* The entry-id field is actually two separated fields: the ms
* and seq difference compared to the master entry.
*
* The lp-count field is a number that states the number of listpack pieces
* that compose the entry, so that it's possible to travel the entry
* in reverse order: we can just start from the end of the listpack, read
* the entry, and jump back N times to seek the "flags" field to read
* the stream full entry. */
lp = lpAppendInteger(lp,flags);
lp = lpAppendInteger(lp,id.ms - master_id.ms);
lp = lpAppendInteger(lp,id.seq - master_id.seq);
if (!(flags & STREAM_ITEM_FLAG_SAMEFIELDS))
lp = lpAppendInteger(lp,numfields);
for (int64_t i = 0; i < numfields; i++) {
sds field = argv[i*2]->ptr, value = argv[i*2+1]->ptr;
if (!(flags & STREAM_ITEM_FLAG_SAMEFIELDS))
lp = lpAppend(lp,(unsigned char*)field,sdslen(field));
lp = lpAppend(lp,(unsigned char*)value,sdslen(value));
}
/* Compute and store the lp-count field. */
int64_t lp_count = numfields;
lp_count += 3; /* Add the 3 fixed fields flags + ms-diff + seq-diff. */
if (!(flags & STREAM_ITEM_FLAG_SAMEFIELDS)) {
/* If the item is not compressed, it also has the fields other than
* the values, and an additional num-fields field. */
lp_count += numfields+1;
}
lp = lpAppendInteger(lp,lp_count);
/* Insert back into the tree in order to update the listpack pointer. */
if (ri.data != lp)
raxInsert(s->rax,(unsigned char*)&rax_key,sizeof(rax_key),lp,NULL);
s->length++;
s->entries_added++;
s->last_id = id;
if (s->length == 1) s->first_id = id;
if (added_id) *added_id = id;
return C_OK;
}
typedef struct {
/* XADD options */
streamID id; /* User-provided ID, for XADD only. */
int id_given; /* Was an ID different than "*" specified? for XADD only. */
int seq_given; /* Was an ID different than "ms-*" specified? for XADD only. */
int no_mkstream; /* if set to 1 do not create new stream */
/* XADD + XTRIM common options */
int trim_strategy; /* TRIM_STRATEGY_* */
int trim_strategy_arg_idx; /* Index of the count in MAXLEN/MINID, for rewriting. */
int approx_trim; /* If 1 only delete whole radix tree nodes, so
* the trim argument is not applied verbatim. */
long long limit; /* Maximum amount of entries to trim. If 0, no limitation
* on the amount of trimming work is enforced. */
/* TRIM_STRATEGY_MAXLEN options */
long long maxlen; /* After trimming, leave stream at this length . */
/* TRIM_STRATEGY_MINID options */
streamID minid; /* Trim by ID (No stream entries with ID < 'minid' will remain) */
} streamAddTrimArgs;
#define TRIM_STRATEGY_NONE 0
#define TRIM_STRATEGY_MAXLEN 1
#define TRIM_STRATEGY_MINID 2
/* Trim the stream 's' according to args->trim_strategy, and return the
* number of elements removed from the stream. The 'approx' option, if non-zero,
* specifies that the trimming must be performed in a approximated way in
* order to maximize performances. This means that the stream may contain
* entries with IDs < 'id' in case of MINID (or more elements than 'maxlen'
* in case of MAXLEN), and elements are only removed if we can remove
* a *whole* node of the radix tree. The elements are removed from the head
* of the stream (older elements).
*
* The function may return zero if:
*
* 1) The minimal entry ID of the stream is already < 'id' (MINID); or
* 2) The stream is already shorter or equal to the specified max length (MAXLEN); or
* 3) The 'approx' option is true and the head node did not have enough elements
* to be deleted.
*
* args->limit is the maximum number of entries to delete. The purpose is to
* prevent this function from taking to long.
* If 'limit' is 0 then we do not limit the number of deleted entries.
* Much like the 'approx', if 'limit' is smaller than the number of entries
* that should be trimmed, there is a chance we will still have entries with
* IDs < 'id' (or number of elements >= maxlen in case of MAXLEN).
*/
int64_t streamTrim(stream *s, streamAddTrimArgs *args) {
size_t maxlen = args->maxlen;
streamID *id = &args->minid;
int approx = args->approx_trim;
int64_t limit = args->limit;
int trim_strategy = args->trim_strategy;
if (trim_strategy == TRIM_STRATEGY_NONE)
return 0;
raxIterator ri;
raxStart(&ri,s->rax);
raxSeek(&ri,"^",NULL,0);
int64_t deleted = 0;
while (raxNext(&ri)) {
if (trim_strategy == TRIM_STRATEGY_MAXLEN && s->length <= maxlen)
break;
unsigned char *lp = ri.data, *p = lpFirst(lp);
int64_t entries = lpGetInteger(p);
/* Check if we exceeded the amount of work we could do */
if (limit && (deleted + entries) > limit)
break;
/* Check if we can remove the whole node. */
int remove_node;
streamID master_id = {0}; /* For MINID */
if (trim_strategy == TRIM_STRATEGY_MAXLEN) {
remove_node = s->length - entries >= maxlen;
} else {
/* Read the master ID from the radix tree key. */
streamDecodeID(ri.key, &master_id);
/* Read last ID. */
streamID last_id = {0,0};
lpGetEdgeStreamID(lp, 0, &master_id, &last_id);
/* We can remove the entire node id its last ID < 'id' */
remove_node = streamCompareID(&last_id, id) < 0;
}
if (remove_node) {
lpFree(lp);
raxRemove(s->rax,ri.key,ri.key_len,NULL);
raxSeek(&ri,">=",ri.key,ri.key_len);
s->length -= entries;
deleted += entries;
continue;
}
/* If we cannot remove a whole element, and approx is true,
* stop here. */
if (approx) break;
/* Now we have to trim entries from within 'lp' */
int64_t deleted_from_lp = 0;
p = lpNext(lp, p); /* Skip deleted field. */
p = lpNext(lp, p); /* Skip num-of-fields in the master entry. */
/* Skip all the master fields. */
int64_t master_fields_count = lpGetInteger(p);
p = lpNext(lp,p); /* Skip the first field. */
for (int64_t j = 0; j < master_fields_count; j++)
p = lpNext(lp,p); /* Skip all master fields. */
p = lpNext(lp,p); /* Skip the zero master entry terminator. */
/* 'p' is now pointing to the first entry inside the listpack.
* We have to run entry after entry, marking entries as deleted
* if they are already not deleted. */
while (p) {
/* We keep a copy of p (which point to flags part) in order to
* update it after (and if) we actually remove the entry */
unsigned char *pcopy = p;
int64_t flags = lpGetInteger(p);
p = lpNext(lp, p); /* Skip flags. */
int64_t to_skip;
int64_t ms_delta = lpGetInteger(p);
p = lpNext(lp, p); /* Skip ID ms delta */
int64_t seq_delta = lpGetInteger(p);
p = lpNext(lp, p); /* Skip ID seq delta */
streamID currid = {0}; /* For MINID */
if (trim_strategy == TRIM_STRATEGY_MINID) {
currid.ms = master_id.ms + ms_delta;
currid.seq = master_id.seq + seq_delta;
}
int stop;
if (trim_strategy == TRIM_STRATEGY_MAXLEN) {
stop = s->length <= maxlen;
} else {
/* Following IDs will definitely be greater because the rax
* tree is sorted, no point of continuing. */
stop = streamCompareID(&currid, id) >= 0;
}
if (stop)
break;
if (flags & STREAM_ITEM_FLAG_SAMEFIELDS) {
to_skip = master_fields_count;
} else {
to_skip = lpGetInteger(p); /* Get num-fields. */
p = lpNext(lp,p); /* Skip num-fields. */
to_skip *= 2; /* Fields and values. */
}
while(to_skip--) p = lpNext(lp,p); /* Skip the whole entry. */
p = lpNext(lp,p); /* Skip the final lp-count field. */
/* Mark the entry as deleted. */
if (!(flags & STREAM_ITEM_FLAG_DELETED)) {
intptr_t delta = p - lp;
flags |= STREAM_ITEM_FLAG_DELETED;
lp = lpReplaceInteger(lp, &pcopy, flags);
deleted_from_lp++;
s->length--;
p = lp + delta;
}
}
deleted += deleted_from_lp;
/* Now we update the entries/deleted counters. */
p = lpFirst(lp);
lp = lpReplaceInteger(lp,&p,entries-deleted_from_lp);
p = lpNext(lp,p); /* Skip deleted field. */
int64_t marked_deleted = lpGetInteger(p);
lp = lpReplaceInteger(lp,&p,marked_deleted+deleted_from_lp);
p = lpNext(lp,p); /* Skip num-of-fields in the master entry. */
/* Here we should perform garbage collection in case at this point
* there are too many entries deleted inside the listpack. */
entries -= deleted_from_lp;
marked_deleted += deleted_from_lp;
if (entries + marked_deleted > 10 && marked_deleted > entries/2) {
/* TODO: perform a garbage collection. */
}
/* Update the listpack with the new pointer. */
raxInsert(s->rax,ri.key,ri.key_len,lp,NULL);
break; /* If we are here, there was enough to delete in the current
node, so no need to go to the next node. */
}
raxStop(&ri);
/* Update the stream's first ID after the trimming. */
if (s->length == 0) {
s->first_id.ms = 0;
s->first_id.seq = 0;
} else if (deleted) {
streamGetEdgeID(s,1,1,&s->first_id);
}
return deleted;
}
/* Trims a stream by length. Returns the number of deleted items. */
int64_t streamTrimByLength(stream *s, long long maxlen, int approx) {
streamAddTrimArgs args = {
.trim_strategy = TRIM_STRATEGY_MAXLEN,
.approx_trim = approx,
.limit = approx ? 100 * server.stream_node_max_entries : 0,
.maxlen = maxlen
};
return streamTrim(s, &args);
}
/* Trims a stream by minimum ID. Returns the number of deleted items. */
int64_t streamTrimByID(stream *s, streamID minid, int approx) {
streamAddTrimArgs args = {
.trim_strategy = TRIM_STRATEGY_MINID,
.approx_trim = approx,
.limit = approx ? 100 * server.stream_node_max_entries : 0,
.minid = minid
};
return streamTrim(s, &args);
}
/* Parse the arguments of XADD/XTRIM.
*
* See streamAddTrimArgs for more details about the arguments handled.
*
* This function returns the position of the ID argument (relevant only to XADD).
* On error -1 is returned and a reply is sent. */
static int streamParseAddOrTrimArgsOrReply(client *c, streamAddTrimArgs *args, int xadd) {
/* Initialize arguments to defaults */
memset(args, 0, sizeof(*args));
/* Parse options. */
int i = 2; /* This is the first argument position where we could
find an option, or the ID. */
int limit_given = 0;
for (; i < c->argc; i++) {
int moreargs = (c->argc-1) - i; /* Number of additional arguments. */
char *opt = c->argv[i]->ptr;
if (xadd && opt[0] == '*' && opt[1] == '\0') {
/* This is just a fast path for the common case of auto-ID
* creation. */
break;
} else if (!strcasecmp(opt,"maxlen") && moreargs) {
if (args->trim_strategy != TRIM_STRATEGY_NONE) {
addReplyError(c,"syntax error, MAXLEN and MINID options at the same time are not compatible");
return -1;
}
args->approx_trim = 0;
char *next = c->argv[i+1]->ptr;
/* Check for the form MAXLEN ~ <count>. */
if (moreargs >= 2 && next[0] == '~' && next[1] == '\0') {
args->approx_trim = 1;
i++;
} else if (moreargs >= 2 && next[0] == '=' && next[1] == '\0') {
i++;
}
if (getLongLongFromObjectOrReply(c,c->argv[i+1],&args->maxlen,NULL)
!= C_OK) return -1;
if (args->maxlen < 0) {
addReplyError(c,"The MAXLEN argument must be >= 0.");
return -1;
}
i++;
args->trim_strategy = TRIM_STRATEGY_MAXLEN;
args->trim_strategy_arg_idx = i;
} else if (!strcasecmp(opt,"minid") && moreargs) {
if (args->trim_strategy != TRIM_STRATEGY_NONE) {
addReplyError(c,"syntax error, MAXLEN and MINID options at the same time are not compatible");
return -1;
}
args->approx_trim = 0;
char *next = c->argv[i+1]->ptr;
/* Check for the form MINID ~ <id> */
if (moreargs >= 2 && next[0] == '~' && next[1] == '\0') {
args->approx_trim = 1;
i++;
} else if (moreargs >= 2 && next[0] == '=' && next[1] == '\0') {
i++;
}
if (streamParseStrictIDOrReply(c,c->argv[i+1],&args->minid,0,NULL) != C_OK)
return -1;
i++;
args->trim_strategy = TRIM_STRATEGY_MINID;
args->trim_strategy_arg_idx = i;
} else if (!strcasecmp(opt,"limit") && moreargs) {
/* Note about LIMIT: If it was not provided by the caller we set
* it to 100*server.stream_node_max_entries, and that's to prevent the
* trimming from taking too long, on the expense of not deleting entries
* that should be trimmed.
* If user wanted exact trimming (i.e. no '~') we never limit the number
* of trimmed entries */
if (getLongLongFromObjectOrReply(c,c->argv[i+1],&args->limit,NULL) != C_OK)
return -1;
if (args->limit < 0) {
addReplyError(c,"The LIMIT argument must be >= 0.");
return -1;
}
limit_given = 1;
i++;
} else if (xadd && !strcasecmp(opt,"nomkstream")) {
args->no_mkstream = 1;
} else if (xadd) {
/* If we are here is a syntax error or a valid ID. */
if (streamParseStrictIDOrReply(c,c->argv[i],&args->id,0,&args->seq_given) != C_OK)
return -1;
args->id_given = 1;
break;
} else {
addReplyErrorObject(c,shared.syntaxerr);
return -1;
}
}
if (args->limit && args->trim_strategy == TRIM_STRATEGY_NONE) {
addReplyError(c,"syntax error, LIMIT cannot be used without specifying a trimming strategy");
return -1;
}
if (!xadd && args->trim_strategy == TRIM_STRATEGY_NONE) {
addReplyError(c,"syntax error, XTRIM must be called with a trimming strategy");
return -1;
}
if (mustObeyClient(c)) {
/* If command came from master or from AOF we must not enforce maxnodes
* (The maxlen/minid argument was re-written to make sure there's no
* inconsistency). */
args->limit = 0;
} else {
/* We need to set the limit (only if we got '~') */
if (limit_given) {
if (!args->approx_trim) {
/* LIMIT was provided without ~ */
addReplyError(c,"syntax error, LIMIT cannot be used without the special ~ option");
return -1;
}
} else {
/* User didn't provide LIMIT, we must set it. */
if (args->approx_trim) {
/* In order to prevent from trimming to do too much work and
* cause latency spikes we limit the amount of work it can do.
* We have to cap args->limit from both sides in case
* stream_node_max_entries is 0 or too big (could cause overflow)
*/
args->limit = 100 * server.stream_node_max_entries; /* Maximum 100 rax nodes. */
if (args->limit <= 0) args->limit = 10000;
if (args->limit > 1000000) args->limit = 1000000;
} else {
/* No LIMIT for exact trimming */
args->limit = 0;
}
}
}
return i;
}
/* Initialize the stream iterator, so that we can call iterating functions
* to get the next items. This requires a corresponding streamIteratorStop()
* at the end. The 'rev' parameter controls the direction. If it's zero the
* iteration is from the start to the end element (inclusive), otherwise
* if rev is non-zero, the iteration is reversed.
*
* Once the iterator is initialized, we iterate like this:
*
* streamIterator myiterator;
* streamIteratorStart(&myiterator,...);
* int64_t numfields;
* while(streamIteratorGetID(&myiterator,&ID,&numfields)) {
* while(numfields--) {
* unsigned char *key, *value;
* size_t key_len, value_len;
* streamIteratorGetField(&myiterator,&key,&value,&key_len,&value_len);
*
* ... do what you want with key and value ...
* }
* }
* streamIteratorStop(&myiterator); */
void streamIteratorStart(streamIterator *si, stream *s, streamID *start, streamID *end, int rev) {
/* Initialize the iterator and translates the iteration start/stop
* elements into a 128 big big-endian number. */
if (start) {
streamEncodeID(si->start_key,start);
} else {
si->start_key[0] = 0;
si->start_key[1] = 0;
}
if (end) {
streamEncodeID(si->end_key,end);
} else {
si->end_key[0] = UINT64_MAX;
si->end_key[1] = UINT64_MAX;
}
/* Seek the correct node in the radix tree. */
raxStart(&si->ri,s->rax);
if (!rev) {
if (start && (start->ms || start->seq)) {
raxSeek(&si->ri,"<=",(unsigned char*)si->start_key,
sizeof(si->start_key));
if (raxEOF(&si->ri)) raxSeek(&si->ri,"^",NULL,0);
} else {
raxSeek(&si->ri,"^",NULL,0);
}
} else {
if (end && (end->ms || end->seq)) {
raxSeek(&si->ri,"<=",(unsigned char*)si->end_key,
sizeof(si->end_key));
if (raxEOF(&si->ri)) raxSeek(&si->ri,"$",NULL,0);
} else {
raxSeek(&si->ri,"$",NULL,0);
}
}
si->stream = s;
si->lp = NULL; /* There is no current listpack right now. */
si->lp_ele = NULL; /* Current listpack cursor. */
si->rev = rev; /* Direction, if non-zero reversed, from end to start. */
si->skip_tombstones = 1; /* By default tombstones aren't emitted. */
}
/* Return 1 and store the current item ID at 'id' if there are still
* elements within the iteration range, otherwise return 0 in order to
* signal the iteration terminated. */
int streamIteratorGetID(streamIterator *si, streamID *id, int64_t *numfields) {
while(1) { /* Will stop when element > stop_key or end of radix tree. */
/* If the current listpack is set to NULL, this is the start of the
* iteration or the previous listpack was completely iterated.
* Go to the next node. */
if (si->lp == NULL || si->lp_ele == NULL) {
if (!si->rev && !raxNext(&si->ri)) return 0;
else if (si->rev && !raxPrev(&si->ri)) return 0;
serverAssert(si->ri.key_len == sizeof(streamID));
/* Get the master ID. */
streamDecodeID(si->ri.key,&si->master_id);
/* Get the master fields count. */
si->lp = si->ri.data;
si->lp_ele = lpFirst(si->lp); /* Seek items count */
si->lp_ele = lpNext(si->lp,si->lp_ele); /* Seek deleted count. */
si->lp_ele = lpNext(si->lp,si->lp_ele); /* Seek num fields. */
si->master_fields_count = lpGetInteger(si->lp_ele);
si->lp_ele = lpNext(si->lp,si->lp_ele); /* Seek first field. */
si->master_fields_start = si->lp_ele;
/* We are now pointing to the first field of the master entry.
* We need to seek either the first or the last entry depending
* on the direction of the iteration. */
if (!si->rev) {
/* If we are iterating in normal order, skip the master fields
* to seek the first actual entry. */
for (uint64_t i = 0; i < si->master_fields_count; i++)
si->lp_ele = lpNext(si->lp,si->lp_ele);
} else {
/* If we are iterating in reverse direction, just seek the
* last part of the last entry in the listpack (that is, the
* fields count). */
si->lp_ele = lpLast(si->lp);
}
} else if (si->rev) {
/* If we are iterating in the reverse order, and this is not
* the first entry emitted for this listpack, then we already
* emitted the current entry, and have to go back to the previous
* one. */
int64_t lp_count = lpGetInteger(si->lp_ele);
while(lp_count--) si->lp_ele = lpPrev(si->lp,si->lp_ele);
/* Seek lp-count of prev entry. */
si->lp_ele = lpPrev(si->lp,si->lp_ele);
}
/* For every radix tree node, iterate the corresponding listpack,
* returning elements when they are within range. */
while(1) {
if (!si->rev) {
/* If we are going forward, skip the previous entry
* lp-count field (or in case of the master entry, the zero
* term field) */
si->lp_ele = lpNext(si->lp,si->lp_ele);
if (si->lp_ele == NULL) break;
} else {
/* If we are going backward, read the number of elements this
* entry is composed of, and jump backward N times to seek
* its start. */
int64_t lp_count = lpGetInteger(si->lp_ele);
if (lp_count == 0) { /* We reached the master entry. */
si->lp = NULL;
si->lp_ele = NULL;
break;
}
while(lp_count--) si->lp_ele = lpPrev(si->lp,si->lp_ele);
}
/* Get the flags entry. */
si->lp_flags = si->lp_ele;
int64_t flags = lpGetInteger(si->lp_ele);
si->lp_ele = lpNext(si->lp,si->lp_ele); /* Seek ID. */
/* Get the ID: it is encoded as difference between the master
* ID and this entry ID. */
*id = si->master_id;
id->ms += lpGetInteger(si->lp_ele);
si->lp_ele = lpNext(si->lp,si->lp_ele);
id->seq += lpGetInteger(si->lp_ele);
si->lp_ele = lpNext(si->lp,si->lp_ele);
unsigned char buf[sizeof(streamID)];
streamEncodeID(buf,id);
/* The number of entries is here or not depending on the
* flags. */
if (flags & STREAM_ITEM_FLAG_SAMEFIELDS) {
*numfields = si->master_fields_count;
} else {
*numfields = lpGetInteger(si->lp_ele);
si->lp_ele = lpNext(si->lp,si->lp_ele);
}
serverAssert(*numfields>=0);
/* If current >= start, and the entry is not marked as
* deleted or tombstones are included, emit it. */
if (!si->rev) {
if (memcmp(buf,si->start_key,sizeof(streamID)) >= 0 &&
(!si->skip_tombstones || !(flags & STREAM_ITEM_FLAG_DELETED)))
{
if (memcmp(buf,si->end_key,sizeof(streamID)) > 0)
return 0; /* We are already out of range. */
si->entry_flags = flags;
if (flags & STREAM_ITEM_FLAG_SAMEFIELDS)
si->master_fields_ptr = si->master_fields_start;
return 1; /* Valid item returned. */
}
} else {
if (memcmp(buf,si->end_key,sizeof(streamID)) <= 0 &&
(!si->skip_tombstones || !(flags & STREAM_ITEM_FLAG_DELETED)))
{
if (memcmp(buf,si->start_key,sizeof(streamID)) < 0)
return 0; /* We are already out of range. */
si->entry_flags = flags;
if (flags & STREAM_ITEM_FLAG_SAMEFIELDS)
si->master_fields_ptr = si->master_fields_start;
return 1; /* Valid item returned. */
}
}
/* If we do not emit, we have to discard if we are going
* forward, or seek the previous entry if we are going
* backward. */
if (!si->rev) {
int64_t to_discard = (flags & STREAM_ITEM_FLAG_SAMEFIELDS) ?
*numfields : *numfields*2;
for (int64_t i = 0; i < to_discard; i++)
si->lp_ele = lpNext(si->lp,si->lp_ele);
} else {
int64_t prev_times = 4; /* flag + id ms + id seq + one more to
go back to the previous entry "count"
field. */
/* If the entry was not flagged SAMEFIELD we also read the
* number of fields, so go back one more. */
if (!(flags & STREAM_ITEM_FLAG_SAMEFIELDS)) prev_times++;
while(prev_times--) si->lp_ele = lpPrev(si->lp,si->lp_ele);
}
}
/* End of listpack reached. Try the next/prev radix tree node. */
}
}
/* Get the field and value of the current item we are iterating. This should
* be called immediately after streamIteratorGetID(), and for each field
* according to the number of fields returned by streamIteratorGetID().
* The function populates the field and value pointers and the corresponding
* lengths by reference, that are valid until the next iterator call, assuming
* no one touches the stream meanwhile. */
void streamIteratorGetField(streamIterator *si, unsigned char **fieldptr, unsigned char **valueptr, int64_t *fieldlen, int64_t *valuelen) {
if (si->entry_flags & STREAM_ITEM_FLAG_SAMEFIELDS) {
*fieldptr = lpGet(si->master_fields_ptr,fieldlen,si->field_buf);
si->master_fields_ptr = lpNext(si->lp,si->master_fields_ptr);
} else {
*fieldptr = lpGet(si->lp_ele,fieldlen,si->field_buf);
si->lp_ele = lpNext(si->lp,si->lp_ele);
}
*valueptr = lpGet(si->lp_ele,valuelen,si->value_buf);
si->lp_ele = lpNext(si->lp,si->lp_ele);
}
/* Remove the current entry from the stream: can be called after the
* GetID() API or after any GetField() call, however we need to iterate
* a valid entry while calling this function. Moreover the function
* requires the entry ID we are currently iterating, that was previously
* returned by GetID().
*
* Note that after calling this function, next calls to GetField() can't
* be performed: the entry is now deleted. Instead the iterator will
* automatically re-seek to the next entry, so the caller should continue
* with GetID(). */
void streamIteratorRemoveEntry(streamIterator *si, streamID *current) {
unsigned char *lp = si->lp;
int64_t aux;
/* We do not really delete the entry here. Instead we mark it as
* deleted by flagging it, and also incrementing the count of the
* deleted entries in the listpack header.
*
* We start flagging: */
int64_t flags = lpGetInteger(si->lp_flags);
flags |= STREAM_ITEM_FLAG_DELETED;
lp = lpReplaceInteger(lp,&si->lp_flags,flags);
/* Change the valid/deleted entries count in the master entry. */
unsigned char *p = lpFirst(lp);
aux = lpGetInteger(p);
if (aux == 1) {
/* If this is the last element in the listpack, we can remove the whole
* node. */
lpFree(lp);
raxRemove(si->stream->rax,si->ri.key,si->ri.key_len,NULL);
} else {
/* In the base case we alter the counters of valid/deleted entries. */
lp = lpReplaceInteger(lp,&p,aux-1);
p = lpNext(lp,p); /* Seek deleted field. */
aux = lpGetInteger(p);
lp = lpReplaceInteger(lp,&p,aux+1);
/* Update the listpack with the new pointer. */
if (si->lp != lp)
raxInsert(si->stream->rax,si->ri.key,si->ri.key_len,lp,NULL);
}
/* Update the number of entries counter. */
si->stream->length--;
/* Re-seek the iterator to fix the now messed up state. */
streamID start, end;
if (si->rev) {
streamDecodeID(si->start_key,&start);
end = *current;
} else {
start = *current;
streamDecodeID(si->end_key,&end);
}
streamIteratorStop(si);
streamIteratorStart(si,si->stream,&start,&end,si->rev);
/* TODO: perform a garbage collection here if the ratio between
* deleted and valid goes over a certain limit. */
}
/* Stop the stream iterator. The only cleanup we need is to free the rax
* iterator, since the stream iterator itself is supposed to be stack
* allocated. */
void streamIteratorStop(streamIterator *si) {
raxStop(&si->ri);
}
/* Return 1 if `id` exists in `s` (and not marked as deleted) */
int streamEntryExists(stream *s, streamID *id) {
streamIterator si;
streamIteratorStart(&si,s,id,id,0);
streamID myid;
int64_t numfields;
int found = streamIteratorGetID(&si,&myid,&numfields);
streamIteratorStop(&si);
if (!found)
return 0;
serverAssert(streamCompareID(id,&myid) == 0);
return 1;
}
/* Delete the specified item ID from the stream, returning 1 if the item
* was deleted 0 otherwise (if it does not exist). */
int streamDeleteItem(stream *s, streamID *id) {
int deleted = 0;
streamIterator si;
streamIteratorStart(&si,s,id,id,0);
streamID myid;
int64_t numfields;
if (streamIteratorGetID(&si,&myid,&numfields)) {
streamIteratorRemoveEntry(&si,&myid);
deleted = 1;
}
streamIteratorStop(&si);
return deleted;
}
/* Get the last valid (non-tombstone) streamID of 's'. */
void streamLastValidID(stream *s, streamID *maxid)
{
streamIterator si;
streamIteratorStart(&si,s,NULL,NULL,1);
int64_t numfields;
if (!streamIteratorGetID(&si,maxid,&numfields) && s->length)
serverPanic("Corrupt stream, length is %llu, but no max id", (unsigned long long)s->length);
streamIteratorStop(&si);
}
/* Maximum size for a stream ID string. In theory 20*2+1 should be enough,
* But to avoid chance for off by one issues and null-term, in case this will
* be used as parsing buffer, we use a slightly larger buffer. On the other
* hand considering sds header is gonna add 4 bytes, we wanna keep below the
* allocator's 48 bytes bin. */
#define STREAM_ID_STR_LEN 44
sds createStreamIDString(streamID *id) {
/* Optimization: pre-allocate a big enough buffer to avoid reallocs. */
sds str = sdsnewlen(SDS_NOINIT, STREAM_ID_STR_LEN);
sdssetlen(str, 0);
return sdscatfmt(str,"%U-%U", id->ms,id->seq);
}
/* Emit a reply in the client output buffer by formatting a Stream ID
* in the standard <ms>-<seq> format, using the simple string protocol
* of REPL. */
void addReplyStreamID(client *c, streamID *id) {
addReplyBulkSds(c,createStreamIDString(id));
}
void setDeferredReplyStreamID(client *c, void *dr, streamID *id) {
setDeferredReplyBulkSds(c, dr, createStreamIDString(id));
}
/* Similar to the above function, but just creates an object, usually useful
* for replication purposes to create arguments. */
robj *createObjectFromStreamID(streamID *id) {
return createObject(OBJ_STRING, createStreamIDString(id));
}
/* Returns non-zero if the ID is 0-0. */
int streamIDEqZero(streamID *id) {
return !(id->ms || id->seq);
}
/* A helper that returns non-zero if the range from 'start' to `end`
* contains a tombstone.
*
* NOTE: this assumes that the caller had verified that 'start' is less than
* 's->last_id'. */
int streamRangeHasTombstones(stream *s, streamID *start, streamID *end) {
streamID start_id, end_id;
if (!s->length || streamIDEqZero(&s->max_deleted_entry_id)) {
/* The stream is empty or has no tombstones. */
return 0;
}
if (streamCompareID(&s->first_id,&s->max_deleted_entry_id) > 0) {
/* The latest tombstone is before the first entry. */
return 0;
}
if (start) {
start_id = *start;
} else {
start_id.ms = 0;
start_id.seq = 0;
}
if (end) {
end_id = *end;
} else {
end_id.ms = UINT64_MAX;
end_id.seq = UINT64_MAX;
}
if (streamCompareID(&start_id,&s->max_deleted_entry_id) <= 0 &&
streamCompareID(&s->max_deleted_entry_id,&end_id) <= 0)
{
/* start_id <= max_deleted_entry_id <= end_id: The range does include a tombstone. */
return 1;
}
/* The range doesn't includes a tombstone. */
return 0;
}
/* Replies with a consumer group's current lag, that is the number of messages
* in the stream that are yet to be delivered. In case that the lag isn't
* available due to fragmentation, the reply to the client is a null. */
void streamReplyWithCGLag(client *c, stream *s, streamCG *cg) {
int valid = 0;
long long lag = 0;
if (!s->entries_added) {
/* The lag of a newly-initialized stream is 0. */
lag = 0;
valid = 1;
} else if (cg->entries_read != SCG_INVALID_ENTRIES_READ && !streamRangeHasTombstones(s,&cg->last_id,NULL)) {
/* No fragmentation ahead means that the group's logical reads counter
* is valid for performing the lag calculation. */
lag = (long long)s->entries_added - cg->entries_read;
valid = 1;
} else {
/* Attempt to retrieve the group's last ID logical read counter. */
long long entries_read = streamEstimateDistanceFromFirstEverEntry(s,&cg->last_id);
if (entries_read != SCG_INVALID_ENTRIES_READ) {
/* A valid counter was obtained. */
lag = (long long)s->entries_added - entries_read;
valid = 1;
}
}
if (valid) {
addReplyLongLong(c,lag);
} else {
addReplyNull(c);
}
}
/* This function returns a value that is the ID's logical read counter, or its
* distance (the number of entries) from the first entry ever to have been added
* to the stream.
*
* A counter is returned only in one of the following cases:
* 1. The ID is the same as the stream's last ID. In this case, the returned
* is the same as the stream's entries_added counter.
* 2. The ID equals that of the currently first entry in the stream, and the
* stream has no tombstones. The returned value, in this case, is the result
* of subtracting the stream's length from its added_entries, incremented by
* one.
* 3. The ID less than the stream's first current entry's ID, and there are no
* tombstones. Here the estimated counter is the result of subtracting the
* stream's length from its added_entries.
* 4. The stream's added_entries is zero, meaning that no entries were ever
* added.
*
* The special return value of ULLONG_MAX signals that the counter's value isn't
* obtainable. It is returned in these cases:
* 1. The provided ID, if it even exists, is somewhere between the stream's
* current first and last entries' IDs, or in the future.
* 2. The stream contains one or more tombstones. */
long long streamEstimateDistanceFromFirstEverEntry(stream *s, streamID *id) {
/* The counter of any ID in an empty, never-before-used stream is 0. */
if (!s->entries_added) {
return 0;
}
/* In the empty stream, if the ID is smaller or equal to the last ID,
* it can set to the current added_entries value. */
if (!s->length && streamCompareID(id,&s->last_id) < 1) {
return s->entries_added;
}
int cmp_last = streamCompareID(id,&s->last_id);
if (cmp_last == 0) {
/* Return the exact counter of the last entry in the stream. */
return s->entries_added;
} else if (cmp_last > 0) {
/* The counter of a future ID is unknown. */
return SCG_INVALID_ENTRIES_READ;
}
int cmp_id_first = streamCompareID(id,&s->first_id);
int cmp_xdel_first = streamCompareID(&s->max_deleted_entry_id,&s->first_id);
if (streamIDEqZero(&s->max_deleted_entry_id) || cmp_xdel_first < 0) {
/* There's definitely no fragmentation ahead. */
if (cmp_id_first < 0) {
/* Return the estimated counter. */
return s->entries_added - s->length;
} else if (cmp_id_first == 0) {
/* Return the exact counter of the first entry in the stream. */
return s->entries_added - s->length + 1;
}
}
/* The ID is either before an XDEL that fragments the stream or an arbitrary
* ID. Either case, so we can't make a prediction. */
return SCG_INVALID_ENTRIES_READ;
}
/* As a result of an explicit XCLAIM or XREADGROUP command, new entries
* are created in the pending list of the stream and consumers. We need
* to propagate this changes in the form of XCLAIM commands. */
void streamPropagateXCLAIM(client *c, robj *key, streamCG *group, robj *groupname, robj *id, streamNACK *nack) {
/* We need to generate an XCLAIM that will work in a idempotent fashion:
*
* XCLAIM <key> <group> <consumer> 0 <id> TIME <milliseconds-unix-time>
* RETRYCOUNT <count> FORCE JUSTID LASTID <id>.
*
* Note that JUSTID is useful in order to avoid that XCLAIM will do
* useless work in the slave side, trying to fetch the stream item. */
robj *argv[14];
argv[0] = shared.xclaim;
argv[1] = key;
argv[2] = groupname;
argv[3] = createStringObject(nack->consumer->name,sdslen(nack->consumer->name));
argv[4] = shared.integers[0];
argv[5] = id;
argv[6] = shared.time;
argv[7] = createStringObjectFromLongLong(nack->delivery_time);
argv[8] = shared.retrycount;
argv[9] = createStringObjectFromLongLong(nack->delivery_count);
argv[10] = shared.force;
argv[11] = shared.justid;
argv[12] = shared.lastid;
argv[13] = createObjectFromStreamID(&group->last_id);
alsoPropagate(c->db->id,argv,14,PROPAGATE_AOF|PROPAGATE_REPL);
decrRefCount(argv[3]);
decrRefCount(argv[7]);
decrRefCount(argv[9]);
decrRefCount(argv[13]);
}
/* We need this when we want to propagate the new last-id of a consumer group
* that was consumed by XREADGROUP with the NOACK option: in that case we can't
* propagate the last ID just using the XCLAIM LASTID option, so we emit
*
* XGROUP SETID <key> <groupname> <id> ENTRIESREAD <entries_read>
*/
void streamPropagateGroupID(client *c, robj *key, streamCG *group, robj *groupname) {
robj *argv[7];
argv[0] = shared.xgroup;
argv[1] = shared.setid;
argv[2] = key;
argv[3] = groupname;
argv[4] = createObjectFromStreamID(&group->last_id);
argv[5] = shared.entriesread;
argv[6] = createStringObjectFromLongLong(group->entries_read);
alsoPropagate(c->db->id,argv,7,PROPAGATE_AOF|PROPAGATE_REPL);
decrRefCount(argv[4]);
decrRefCount(argv[6]);
}
/* We need this when we want to propagate creation of consumer that was created
* by XREADGROUP with the NOACK option. In that case, the only way to create
* the consumer at the replica is by using XGROUP CREATECONSUMER (see issue #7140)
*
* XGROUP CREATECONSUMER <key> <groupname> <consumername>
*/
void streamPropagateConsumerCreation(client *c, robj *key, robj *groupname, sds consumername) {
robj *argv[5];
argv[0] = shared.xgroup;
argv[1] = shared.createconsumer;
argv[2] = key;
argv[3] = groupname;
argv[4] = createObject(OBJ_STRING,sdsdup(consumername));
alsoPropagate(c->db->id,argv,5,PROPAGATE_AOF|PROPAGATE_REPL);
decrRefCount(argv[4]);
}
/* Send the stream items in the specified range to the client 'c'. The range
* the client will receive is between start and end inclusive, if 'count' is
* non zero, no more than 'count' elements are sent.
*
* The 'end' pointer can be NULL to mean that we want all the elements from
* 'start' till the end of the stream. If 'rev' is non zero, elements are
* produced in reversed order from end to start.
*
* The function returns the number of entries emitted.
*
* If group and consumer are not NULL, the function performs additional work:
* 1. It updates the last delivered ID in the group in case we are
* sending IDs greater than the current last ID.
* 2. If the requested IDs are already assigned to some other consumer, the
* function will not return it to the client.
* 3. An entry in the pending list will be created for every entry delivered
* for the first time to this consumer.
* 4. The group's read counter is incremented if it is already valid and there
* are no future tombstones, or is invalidated (set to 0) otherwise. If the
* counter is invalid to begin with, we try to obtain it for the last
* delivered ID.
*
* The behavior may be modified passing non-zero flags:
*
* STREAM_RWR_NOACK: Do not create PEL entries, that is, the point "3" above
* is not performed.
* STREAM_RWR_RAWENTRIES: Do not emit array boundaries, but just the entries,
* and return the number of entries emitted as usually.
* This is used when the function is just used in order
* to emit data and there is some higher level logic.
*
* The final argument 'spi' (stream propagation info pointer) is a structure
* filled with information needed to propagate the command execution to AOF
* and slaves, in the case a consumer group was passed: we need to generate
* XCLAIM commands to create the pending list into AOF/slaves in that case.
*
* If 'spi' is set to NULL no propagation will happen even if the group was
* given, but currently such a feature is never used by the code base that
* will always pass 'spi' and propagate when a group is passed.
*
* Note that this function is recursive in certain cases. When it's called
* with a non NULL group and consumer argument, it may call
* streamReplyWithRangeFromConsumerPEL() in order to get entries from the
* consumer pending entries list. However such a function will then call
* streamReplyWithRange() in order to emit single entries (found in the
* PEL by ID) to the client. This is the use case for the STREAM_RWR_RAWENTRIES
* flag.
*/
#define STREAM_RWR_NOACK (1<<0) /* Do not create entries in the PEL. */
#define STREAM_RWR_RAWENTRIES (1<<1) /* Do not emit protocol for array
boundaries, just the entries. */
#define STREAM_RWR_HISTORY (1<<2) /* Only serve consumer local PEL. */
size_t streamReplyWithRange(client *c, stream *s, streamID *start, streamID *end, size_t count, int rev, streamCG *group, streamConsumer *consumer, int flags, streamPropInfo *spi) {
void *arraylen_ptr = NULL;
size_t arraylen = 0;
streamIterator si;
int64_t numfields;
streamID id;
int propagate_last_id = 0;
int noack = flags & STREAM_RWR_NOACK;
/* If the client is asking for some history, we serve it using a
* different function, so that we return entries *solely* from its
* own PEL. This ensures each consumer will always and only see
* the history of messages delivered to it and not yet confirmed
* as delivered. */
if (group && (flags & STREAM_RWR_HISTORY)) {
return streamReplyWithRangeFromConsumerPEL(c,s,start,end,count,
consumer);
}
if (!(flags & STREAM_RWR_RAWENTRIES))
arraylen_ptr = addReplyDeferredLen(c);
streamIteratorStart(&si,s,start,end,rev);
while(streamIteratorGetID(&si,&id,&numfields)) {
/* Update the group last_id if needed. */
if (group && streamCompareID(&id,&group->last_id) > 0) {
if (group->entries_read != SCG_INVALID_ENTRIES_READ && !streamRangeHasTombstones(s,&id,NULL)) {
/* A valid counter and no future tombstones mean we can
* increment the read counter to keep tracking the group's
* progress. */
group->entries_read++;
} else if (s->entries_added) {
/* The group's counter may be invalid, so we try to obtain it. */
group->entries_read = streamEstimateDistanceFromFirstEverEntry(s,&id);
}
group->last_id = id;
/* In the past, we would only set it when NOACK was specified. And in
* #9127, XCLAIM did not propagate entries_read in ACK, which would
* cause entries_read to be inconsistent between master and replicas,
* so here we call streamPropagateGroupID unconditionally. */
propagate_last_id = 1;
}
/* Emit a two elements array for each item. The first is
* the ID, the second is an array of field-value pairs. */
addReplyArrayLen(c,2);
addReplyStreamID(c,&id);
addReplyArrayLen(c,numfields*2);
/* Emit the field-value pairs. */
while(numfields--) {
unsigned char *key, *value;
int64_t key_len, value_len;
streamIteratorGetField(&si,&key,&value,&key_len,&value_len);
addReplyBulkCBuffer(c,key,key_len);
addReplyBulkCBuffer(c,value,value_len);
}
/* If a group is passed, we need to create an entry in the
* PEL (pending entries list) of this group *and* this consumer.
*
* Note that we cannot be sure about the fact the message is not
* already owned by another consumer, because the admin is able
* to change the consumer group last delivered ID using the
* XGROUP SETID command. So if we find that there is already
* a NACK for the entry, we need to associate it to the new
* consumer. */
if (group && !noack) {
unsigned char buf[sizeof(streamID)];
streamEncodeID(buf,&id);
/* Try to add a new NACK. Most of the time this will work and
* will not require extra lookups. We'll fix the problem later
* if we find that there is already a entry for this ID. */
streamNACK *nack = streamCreateNACK(consumer);
int group_inserted =
raxTryInsert(group->pel,buf,sizeof(buf),nack,NULL);
int consumer_inserted =
raxTryInsert(consumer->pel,buf,sizeof(buf),nack,NULL);
/* Now we can check if the entry was already busy, and
* in that case reassign the entry to the new consumer,
* or update it if the consumer is the same as before. */
if (group_inserted == 0) {
streamFreeNACK(nack);
void *result;
int found = raxFind(group->pel,buf,sizeof(buf),&result);
serverAssert(found);
nack = result;
raxRemove(nack->consumer->pel,buf,sizeof(buf),NULL);
/* Update the consumer and NACK metadata. */
nack->consumer = consumer;
nack->delivery_time = commandTimeSnapshot();
nack->delivery_count = 1;
/* Add the entry in the new consumer local PEL. */
raxInsert(consumer->pel,buf,sizeof(buf),nack,NULL);
} else if (group_inserted == 1 && consumer_inserted == 0) {
serverPanic("NACK half-created. Should not be possible.");
}
consumer->active_time = commandTimeSnapshot();
/* Propagate as XCLAIM. */
if (spi) {
robj *idarg = createObjectFromStreamID(&id);
streamPropagateXCLAIM(c,spi->keyname,group,spi->groupname,idarg,nack);
decrRefCount(idarg);
}
}
arraylen++;
if (count && count == arraylen) break;
}
if (spi && propagate_last_id)
streamPropagateGroupID(c,spi->keyname,group,spi->groupname);
streamIteratorStop(&si);
if (arraylen_ptr) setDeferredArrayLen(c,arraylen_ptr,arraylen);
return arraylen;
}
/* This is a helper function for streamReplyWithRange() when called with
* group and consumer arguments, but with a range that is referring to already
* delivered messages. In this case we just emit messages that are already
* in the history of the consumer, fetching the IDs from its PEL.
*
* Note that this function does not have a 'rev' argument because it's not
* possible to iterate in reverse using a group. Basically this function
* is only called as a result of the XREADGROUP command.
*
* This function is more expensive because it needs to inspect the PEL and then
* seek into the radix tree of the messages in order to emit the full message
* to the client. However clients only reach this code path when they are
* fetching the history of already retrieved messages, which is rare. */
size_t streamReplyWithRangeFromConsumerPEL(client *c, stream *s, streamID *start, streamID *end, size_t count, streamConsumer *consumer) {
raxIterator ri;
unsigned char startkey[sizeof(streamID)];
unsigned char endkey[sizeof(streamID)];
streamEncodeID(startkey,start);
if (end) streamEncodeID(endkey,end);
size_t arraylen = 0;
void *arraylen_ptr = addReplyDeferredLen(c);
raxStart(&ri,consumer->pel);
raxSeek(&ri,">=",startkey,sizeof(startkey));
while(raxNext(&ri) && (!count || arraylen < count)) {
if (end && memcmp(ri.key,end,ri.key_len) > 0) break;
streamID thisid;
streamDecodeID(ri.key,&thisid);
if (streamReplyWithRange(c,s,&thisid,&thisid,1,0,NULL,NULL,
STREAM_RWR_RAWENTRIES,NULL) == 0)
{
/* Note that we may have a not acknowledged entry in the PEL
* about a message that's no longer here because was removed
* by the user by other means. In that case we signal it emitting
* the ID but then a NULL entry for the fields. */
addReplyArrayLen(c,2);
addReplyStreamID(c,&thisid);
addReplyNullArray(c);
} else {
streamNACK *nack = ri.data;
nack->delivery_time = commandTimeSnapshot();
nack->delivery_count++;
}
arraylen++;
}
raxStop(&ri);
setDeferredArrayLen(c,arraylen_ptr,arraylen);
return arraylen;
}
/* -----------------------------------------------------------------------
* Stream commands implementation
* ----------------------------------------------------------------------- */
/* Look the stream at 'key' and return the corresponding stream object.
* The function creates a key setting it to an empty stream if needed. */
robj *streamTypeLookupWriteOrCreate(client *c, robj *key, int no_create) {
robj *o = lookupKeyWrite(c->db,key);
if (checkType(c,o,OBJ_STREAM)) return NULL;
if (o == NULL) {
if (no_create) {
addReplyNull(c);
return NULL;
}
o = createStreamObject();
dbAdd(c->db,key,o);
}
return o;
}
/* Parse a stream ID in the format given by clients to Redis, that is
* <ms>-<seq>, and converts it into a streamID structure. If
* the specified ID is invalid C_ERR is returned and an error is reported
* to the client, otherwise C_OK is returned. The ID may be in incomplete
* form, just stating the milliseconds time part of the stream. In such a case
* the missing part is set according to the value of 'missing_seq' parameter.
*
* The IDs "-" and "+" specify respectively the minimum and maximum IDs
* that can be represented. If 'strict' is set to 1, "-" and "+" will be
* treated as an invalid ID.
*
* The ID form <ms>-* specifies a millisconds-only ID, leaving the sequence part
* to be autogenerated. When a non-NULL 'seq_given' argument is provided, this
* form is accepted and the argument is set to 0 unless the sequence part is
* specified.
*
* If 'c' is set to NULL, no reply is sent to the client. */
int streamGenericParseIDOrReply(client *c, const robj *o, streamID *id, uint64_t missing_seq, int strict, int *seq_given) {
char buf[128];
if (sdslen(o->ptr) > sizeof(buf)-1) goto invalid;
memcpy(buf,o->ptr,sdslen(o->ptr)+1);
if (strict && (buf[0] == '-' || buf[0] == '+') && buf[1] == '\0')
goto invalid;
if (seq_given != NULL) {
*seq_given = 1;
}
/* Handle the "-" and "+" special cases. */
if (buf[0] == '-' && buf[1] == '\0') {
id->ms = 0;
id->seq = 0;
return C_OK;
} else if (buf[0] == '+' && buf[1] == '\0') {
id->ms = UINT64_MAX;
id->seq = UINT64_MAX;
return C_OK;
}
/* Parse <ms>-<seq> form. */
unsigned long long ms, seq;
char *dot = strchr(buf,'-');
if (dot) *dot = '\0';
if (string2ull(buf,&ms) == 0) goto invalid;
if (dot) {
size_t seqlen = strlen(dot+1);
if (seq_given != NULL && seqlen == 1 && *(dot + 1) == '*') {
/* Handle the <ms>-* form. */
seq = 0;
*seq_given = 0;
} else if (string2ull(dot+1,&seq) == 0) {
goto invalid;
}
} else {
seq = missing_seq;
}
id->ms = ms;
id->seq = seq;
return C_OK;
invalid:
if (c) addReplyError(c,"Invalid stream ID specified as stream "
"command argument");
return C_ERR;
}
/* Wrapper for streamGenericParseIDOrReply() used by module API. */
int streamParseID(const robj *o, streamID *id) {
return streamGenericParseIDOrReply(NULL,o,id,0,0,NULL);
}
/* Wrapper for streamGenericParseIDOrReply() with 'strict' argument set to
* 0, to be used when - and + are acceptable IDs. */
int streamParseIDOrReply(client *c, robj *o, streamID *id, uint64_t missing_seq) {
return streamGenericParseIDOrReply(c,o,id,missing_seq,0,NULL);
}
/* Wrapper for streamGenericParseIDOrReply() with 'strict' argument set to
* 1, to be used when we want to return an error if the special IDs + or -
* are provided. */
int streamParseStrictIDOrReply(client *c, robj *o, streamID *id, uint64_t missing_seq, int *seq_given) {
return streamGenericParseIDOrReply(c,o,id,missing_seq,1,seq_given);
}
/* Helper for parsing a stream ID that is a range query interval. When the
* exclude argument is NULL, streamParseIDOrReply() is called and the interval
* is treated as close (inclusive). Otherwise, the exclude argument is set if
* the interval is open (the "(" prefix) and streamParseStrictIDOrReply() is
* called in that case.
*/
int streamParseIntervalIDOrReply(client *c, robj *o, streamID *id, int *exclude, uint64_t missing_seq) {
char *p = o->ptr;
size_t len = sdslen(p);
int invalid = 0;
if (exclude != NULL) *exclude = (len > 1 && p[0] == '(');
if (exclude != NULL && *exclude) {
robj *t = createStringObject(p+1,len-1);
invalid = (streamParseStrictIDOrReply(c,t,id,missing_seq,NULL) == C_ERR);
decrRefCount(t);
} else
invalid = (streamParseIDOrReply(c,o,id,missing_seq) == C_ERR);
if (invalid)
return C_ERR;
return C_OK;
}
void streamRewriteApproxSpecifier(client *c, int idx) {
rewriteClientCommandArgument(c,idx,shared.special_equals);
}
/* We propagate MAXLEN/MINID ~ <count> as MAXLEN/MINID = <resulting-len-of-stream>
* otherwise trimming is no longer deterministic on replicas / AOF. */
void streamRewriteTrimArgument(client *c, stream *s, int trim_strategy, int idx) {
robj *arg;
if (trim_strategy == TRIM_STRATEGY_MAXLEN) {
arg = createStringObjectFromLongLong(s->length);
} else {
streamID first_id;
streamGetEdgeID(s,1,0,&first_id);
arg = createObjectFromStreamID(&first_id);
}
rewriteClientCommandArgument(c,idx,arg);
decrRefCount(arg);
}
/* XADD key [(MAXLEN [~|=] <count> | MINID [~|=] <id>) [LIMIT <entries>]] [NOMKSTREAM] <ID or *> [field value] [field value] ... */
void xaddCommand(client *c) {
/* Parse options. */
streamAddTrimArgs parsed_args;
int idpos = streamParseAddOrTrimArgsOrReply(c, &parsed_args, 1);
if (idpos < 0)
return; /* streamParseAddOrTrimArgsOrReply already replied. */
int field_pos = idpos+1; /* The ID is always one argument before the first field */
/* Check arity. */
if ((c->argc - field_pos) < 2 || ((c->argc-field_pos) % 2) == 1) {
addReplyErrorArity(c);
return;
}
/* Return ASAP if minimal ID (0-0) was given so we avoid possibly creating
* a new stream and have streamAppendItem fail, leaving an empty key in the
* database. */
if (parsed_args.id_given && parsed_args.seq_given &&
parsed_args.id.ms == 0 && parsed_args.id.seq == 0)
{
addReplyError(c,"The ID specified in XADD must be greater than 0-0");
return;
}
/* Lookup the stream at key. */
robj *o;
stream *s;
if ((o = streamTypeLookupWriteOrCreate(c,c->argv[1],parsed_args.no_mkstream)) == NULL) return;
s = o->ptr;
/* Return ASAP if the stream has reached the last possible ID */
if (s->last_id.ms == UINT64_MAX && s->last_id.seq == UINT64_MAX) {
addReplyError(c,"The stream has exhausted the last possible ID, "
"unable to add more items");
return;
}
/* Append using the low level function and return the ID. */
errno = 0;
streamID id;
if (streamAppendItem(s,c->argv+field_pos,(c->argc-field_pos)/2,
&id,parsed_args.id_given ? &parsed_args.id : NULL,parsed_args.seq_given) == C_ERR)
{
serverAssert(errno != 0);
if (errno == EDOM)
addReplyError(c,"The ID specified in XADD is equal or smaller than "
"the target stream top item");
else
addReplyError(c,"Elements are too large to be stored");
return;
}
sds replyid = createStreamIDString(&id);
addReplyBulkCBuffer(c, replyid, sdslen(replyid));
notifyKeyspaceEvent(NOTIFY_STREAM,"xadd",c->argv[1],c->db->id);
server.dirty++;
/* Trim if needed. */
if (parsed_args.trim_strategy != TRIM_STRATEGY_NONE) {
if (streamTrim(s, &parsed_args)) {
notifyKeyspaceEvent(NOTIFY_STREAM,"xtrim",c->argv[1],c->db->id);
}
if (parsed_args.approx_trim) {
/* In case our trimming was limited (by LIMIT or by ~) we must
* re-write the relevant trim argument to make sure there will be
* no inconsistencies in AOF loading or in the replica.
* It's enough to check only args->approx because there is no
* way LIMIT is given without the ~ option. */
streamRewriteApproxSpecifier(c,parsed_args.trim_strategy_arg_idx-1);
streamRewriteTrimArgument(c,s,parsed_args.trim_strategy,parsed_args.trim_strategy_arg_idx);
}
}
signalModifiedKey(c,c->db,c->argv[1]);
/* Let's rewrite the ID argument with the one actually generated for
* AOF/replication propagation. */
if (!parsed_args.id_given || !parsed_args.seq_given) {
robj *idarg = createObject(OBJ_STRING, replyid);
rewriteClientCommandArgument(c, idpos, idarg);
decrRefCount(idarg);
} else {
sdsfree(replyid);
}
/* We need to signal to blocked clients that there is new data on this
* stream. */
signalKeyAsReady(c->db, c->argv[1], OBJ_STREAM);
}
/* XRANGE/XREVRANGE actual implementation.
* The 'start' and 'end' IDs are parsed as follows:
* Incomplete 'start' has its sequence set to 0, and 'end' to UINT64_MAX.
* "-" and "+"" mean the minimal and maximal ID values, respectively.
* The "(" prefix means an open (exclusive) range, so XRANGE stream (1-0 (2-0
* will match anything from 1-1 and 1-UINT64_MAX.
*/
void xrangeGenericCommand(client *c, int rev) {
robj *o;
stream *s;
streamID startid, endid;
long long count = -1;
robj *startarg = rev ? c->argv[3] : c->argv[2];
robj *endarg = rev ? c->argv[2] : c->argv[3];
int startex = 0, endex = 0;
/* Parse start and end IDs. */
if (streamParseIntervalIDOrReply(c,startarg,&startid,&startex,0) != C_OK)
return;
if (startex && streamIncrID(&startid) != C_OK) {
addReplyError(c,"invalid start ID for the interval");
return;
}
if (streamParseIntervalIDOrReply(c,endarg,&endid,&endex,UINT64_MAX) != C_OK)
return;
if (endex && streamDecrID(&endid) != C_OK) {
addReplyError(c,"invalid end ID for the interval");
return;
}
/* Parse the COUNT option if any. */
if (c->argc > 4) {
for (int j = 4; j < c->argc; j++) {
int additional = c->argc-j-1;
if (strcasecmp(c->argv[j]->ptr,"COUNT") == 0 && additional >= 1) {
if (getLongLongFromObjectOrReply(c,c->argv[j+1],&count,NULL)
!= C_OK) return;
if (count < 0) count = 0;
j++; /* Consume additional arg. */
} else {
addReplyErrorObject(c,shared.syntaxerr);
return;
}
}
}
/* Return the specified range to the user. */
if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.emptyarray)) == NULL ||
checkType(c,o,OBJ_STREAM)) return;
s = o->ptr;
if (count == 0) {
addReplyNullArray(c);
} else {
if (count == -1) count = 0;
streamReplyWithRange(c,s,&startid,&endid,count,rev,NULL,NULL,0,NULL);
}
}
/* XRANGE key start end [COUNT <n>] */
void xrangeCommand(client *c) {
xrangeGenericCommand(c,0);
}
/* XREVRANGE key end start [COUNT <n>] */
void xrevrangeCommand(client *c) {
xrangeGenericCommand(c,1);
}
/* XLEN key*/
void xlenCommand(client *c) {
robj *o;
if ((o = lookupKeyReadOrReply(c,c->argv[1],shared.czero)) == NULL
|| checkType(c,o,OBJ_STREAM)) return;
stream *s = o->ptr;
addReplyLongLong(c,s->length);
}
/* XREAD [BLOCK <milliseconds>] [COUNT <count>] STREAMS key_1 key_2 ... key_N
* ID_1 ID_2 ... ID_N
*
* This function also implements the XREADGROUP command, which is like XREAD
* but accepting the [GROUP group-name consumer-name] additional option.
* This is useful because while XREAD is a read command and can be called
* on slaves, XREADGROUP is not. */
#define XREAD_BLOCKED_DEFAULT_COUNT 1000
void xreadCommand(client *c) {
long long timeout = -1; /* -1 means, no BLOCK argument given. */
long long count = 0;
int streams_count = 0;
int streams_arg = 0;
int noack = 0; /* True if NOACK option was specified. */
streamID static_ids[STREAMID_STATIC_VECTOR_LEN];
streamID *ids = static_ids;
streamCG **groups = NULL;
int xreadgroup = sdslen(c->argv[0]->ptr) == 10; /* XREAD or XREADGROUP? */
robj *groupname = NULL;
robj *consumername = NULL;
/* Parse arguments. */
for (int i = 1; i < c->argc; i++) {
int moreargs = c->argc-i-1;
char *o = c->argv[i]->ptr;
if (!strcasecmp(o,"BLOCK") && moreargs) {
i++;
if (getTimeoutFromObjectOrReply(c,c->argv[i],&timeout,
UNIT_MILLISECONDS) != C_OK) return;
} else if (!strcasecmp(o,"COUNT") && moreargs) {
i++;
if (getLongLongFromObjectOrReply(c,c->argv[i],&count,NULL) != C_OK)
return;
if (count < 0) count = 0;
} else if (!strcasecmp(o,"STREAMS") && moreargs) {
streams_arg = i+1;
streams_count = (c->argc-streams_arg);
if ((streams_count % 2) != 0) {
char symbol = xreadgroup ? '>' : '$';
addReplyErrorFormat(c,"Unbalanced '%s' list of streams: "
"for each stream key an ID or '%c' must be "
"specified.", c->cmd->fullname,symbol);
return;
}
streams_count /= 2; /* We have two arguments for each stream. */
break;
} else if (!strcasecmp(o,"GROUP") && moreargs >= 2) {
if (!xreadgroup) {
addReplyError(c,"The GROUP option is only supported by "
"XREADGROUP. You called XREAD instead.");
return;
}
groupname = c->argv[i+1];
consumername = c->argv[i+2];
i += 2;
} else if (!strcasecmp(o,"NOACK")) {
if (!xreadgroup) {
addReplyError(c,"The NOACK option is only supported by "
"XREADGROUP. You called XREAD instead.");
return;
}
noack = 1;
} else {
addReplyErrorObject(c,shared.syntaxerr);
return;
}
}
/* STREAMS option is mandatory. */
if (streams_arg == 0) {
addReplyErrorObject(c,shared.syntaxerr);
return;
}
/* If the user specified XREADGROUP then it must also
* provide the GROUP option. */
if (xreadgroup && groupname == NULL) {
addReplyError(c,"Missing GROUP option for XREADGROUP");
return;
}
/* Parse the IDs and resolve the group name. */
if (streams_count > STREAMID_STATIC_VECTOR_LEN)
ids = zmalloc(sizeof(streamID)*streams_count);
if (groupname) groups = zmalloc(sizeof(streamCG*)*streams_count);
for (int i = streams_arg + streams_count; i < c->argc; i++) {
/* Specifying "$" as last-known-id means that the client wants to be
* served with just the messages that will arrive into the stream
* starting from now. */
int id_idx = i - streams_arg - streams_count;
robj *key = c->argv[i-streams_count];
robj *o = lookupKeyRead(c->db,key);
if (checkType(c,o,OBJ_STREAM)) goto cleanup;
streamCG *group = NULL;
/* If a group was specified, than we need to be sure that the
* key and group actually exist. */
if (groupname) {
if (o == NULL ||
(group = streamLookupCG(o->ptr,groupname->ptr)) == NULL)
{
addReplyErrorFormat(c, "-NOGROUP No such key '%s' or consumer "
"group '%s' in XREADGROUP with GROUP "
"option",
(char*)key->ptr,(char*)groupname->ptr);
goto cleanup;
}
groups[id_idx] = group;
}
if (strcmp(c->argv[i]->ptr,"$") == 0) {
if (xreadgroup) {
addReplyError(c,"The $ ID is meaningless in the context of "
"XREADGROUP: you want to read the history of "
"this consumer by specifying a proper ID, or "
"use the > ID to get new messages. The $ ID would "
"just return an empty result set.");
goto cleanup;
}
if (o) {
stream *s = o->ptr;
ids[id_idx] = s->last_id;
} else {
ids[id_idx].ms = 0;
ids[id_idx].seq = 0;
}
continue;
} else if (strcmp(c->argv[i]->ptr,"+") == 0) {
if (xreadgroup) {
addReplyError(c,"The + ID is meaningless in the context of "
"XREADGROUP: you want to read the history of "
"this consumer by specifying a proper ID, or "
"use the > ID to get new messages. The + ID would "
"just return an empty result set.");
goto cleanup;
}
if (o) {
stream *s = o->ptr;
ids[id_idx] = s->last_id;
if (streamDecrID(&ids[id_idx]) != C_OK) {
/* shouldn't happen */
addReplyError(c,"the stream last element ID is 0-0");
goto cleanup;
}
} else {
ids[id_idx].ms = 0;
ids[id_idx].seq = 0;
}
continue;
} else if (strcmp(c->argv[i]->ptr,">") == 0) {
if (!xreadgroup) {
addReplyError(c,"The > ID can be specified only when calling "
"XREADGROUP using the GROUP <group> "
"<consumer> option.");
goto cleanup;
}
/* We use just the maximum ID to signal this is a ">" ID, anyway
* the code handling the blocking clients will have to update the
* ID later in order to match the changing consumer group last ID. */
ids[id_idx].ms = UINT64_MAX;
ids[id_idx].seq = UINT64_MAX;
continue;
}
if (streamParseStrictIDOrReply(c,c->argv[i],ids+id_idx,0,NULL) != C_OK)
goto cleanup;
}
/* Try to serve the client synchronously. */
size_t arraylen = 0;
void *arraylen_ptr = NULL;
for (int i = 0; i < streams_count; i++) {
robj *o = lookupKeyRead(c->db,c->argv[streams_arg+i]);
if (o == NULL) continue;
stream *s = o->ptr;
streamID *gt = ids+i; /* ID must be greater than this. */
int serve_synchronously = 0;
int serve_history = 0; /* True for XREADGROUP with ID != ">". */
streamConsumer *consumer = NULL; /* Unused if XREAD */
streamPropInfo spi = {c->argv[streams_arg+i],groupname}; /* Unused if XREAD */
/* Check if there are the conditions to serve the client
* synchronously. */
if (groups) {
/* If the consumer is blocked on a group, we always serve it
* synchronously (serving its local history) if the ID specified
* was not the special ">" ID. */
if (gt->ms != UINT64_MAX ||
gt->seq != UINT64_MAX)
{
serve_synchronously = 1;
serve_history = 1;
} else if (s->length) {
/* We also want to serve a consumer in a consumer group
* synchronously in case the group top item delivered is smaller
* than what the stream has inside. */
streamID maxid, *last = &groups[i]->last_id;
streamLastValidID(s, &maxid);
if (streamCompareID(&maxid, last) > 0) {
serve_synchronously = 1;
*gt = *last;
}
}
consumer = streamLookupConsumer(groups[i],consumername->ptr);
if (consumer == NULL) {
consumer = streamCreateConsumer(groups[i],consumername->ptr,
c->argv[streams_arg+i],
c->db->id,SCC_DEFAULT);
if (noack)
streamPropagateConsumerCreation(c,spi.keyname,
spi.groupname,
consumer->name);
}
consumer->seen_time = commandTimeSnapshot();
} else if (s->length) {
/* For consumers without a group, we serve synchronously if we can
* actually provide at least one item from the stream. */
streamID maxid;
streamLastValidID(s, &maxid);
if (streamCompareID(&maxid, gt) > 0) {
serve_synchronously = 1;
}
}
if (serve_synchronously) {
arraylen++;
if (arraylen == 1) arraylen_ptr = addReplyDeferredLen(c);
/* streamReplyWithRange() handles the 'start' ID as inclusive,
* so start from the next ID, since we want only messages with
* IDs greater than start. */
streamID start = *gt;
streamIncrID(&start);
/* Emit the two elements sub-array consisting of the name
* of the stream and the data we extracted from it. */
if (c->resp == 2) addReplyArrayLen(c,2);
addReplyBulk(c,c->argv[streams_arg+i]);
int flags = 0;
if (noack) flags |= STREAM_RWR_NOACK;
if (serve_history) flags |= STREAM_RWR_HISTORY;
streamReplyWithRange(c,s,&start,NULL,count,0,
groups ? groups[i] : NULL,
consumer, flags, &spi);
if (groups) server.dirty++;
}
}
/* We replied synchronously! Set the top array len and return to caller. */
if (arraylen) {
if (c->resp == 2)
setDeferredArrayLen(c,arraylen_ptr,arraylen);
else
setDeferredMapLen(c,arraylen_ptr,arraylen);
goto cleanup;
}
/* Block if needed. */
if (timeout != -1) {
/* 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);
goto cleanup;
}
/* We change the '$' to the current last ID for this stream. this is
* Since later on when we unblock on arriving data - we would like to
* re-process the command and in case '$' stays we will spin-block forever.
*/
for (int id_idx = 0; id_idx < streams_count; id_idx++) {
int arg_idx = id_idx + streams_arg + streams_count;
if (strcmp(c->argv[arg_idx]->ptr,"$") == 0) {
robj *argv_streamid = createObjectFromStreamID(&ids[id_idx]);
rewriteClientCommandArgument(c, arg_idx, argv_streamid);
decrRefCount(argv_streamid);
}
}
blockForKeys(c, BLOCKED_STREAM, c->argv+streams_arg, streams_count, timeout, xreadgroup);
goto cleanup;
}
/* No BLOCK option, nor any stream we can serve. Reply as with a
* timeout happened. */
addReplyNullArray(c);
/* Continue to cleanup... */
cleanup: /* Cleanup. */
/* The command is propagated (in the READGROUP form) as a side effect
* of calling lower level APIs. So stop any implicit propagation. */
preventCommandPropagation(c);
if (ids != static_ids) zfree(ids);
zfree(groups);
}
/* -----------------------------------------------------------------------
* Low level implementation of consumer groups
* ----------------------------------------------------------------------- */
/* Create a NACK entry setting the delivery count to 1 and the delivery
* time to the current time. The NACK consumer will be set to the one
* specified as argument of the function. */
streamNACK *streamCreateNACK(streamConsumer *consumer) {
streamNACK *nack = zmalloc(sizeof(*nack));
nack->delivery_time = commandTimeSnapshot();
nack->delivery_count = 1;
nack->consumer = consumer;
return nack;
}
/* Free a NACK entry. */
void streamFreeNACK(streamNACK *na) {
zfree(na);
}
/* Free a consumer and associated data structures. Note that this function
* will not reassign the pending messages associated with this consumer
* nor will delete them from the stream, so when this function is called
* to delete a consumer, and not when the whole stream is destroyed, the caller
* should do some work before. */
void streamFreeConsumer(streamConsumer *sc) {
raxFree(sc->pel); /* No value free callback: the PEL entries are shared
between the consumer and the main stream PEL. */
sdsfree(sc->name);
zfree(sc);
}
/* Create a new consumer group in the context of the stream 's', having the
* specified name, last server ID and reads counter. If a consumer group with
* the same name already exists NULL is returned, otherwise the pointer to the
* consumer group is returned. */
streamCG *streamCreateCG(stream *s, char *name, size_t namelen, streamID *id, long long entries_read) {
if (s->cgroups == NULL) s->cgroups = raxNew();
if (raxFind(s->cgroups,(unsigned char*)name,namelen,NULL))
return NULL;
streamCG *cg = zmalloc(sizeof(*cg));
cg->pel = raxNew();
cg->consumers = raxNew();
cg->last_id = *id;
cg->entries_read = entries_read;
raxInsert(s->cgroups,(unsigned char*)name,namelen,cg,NULL);
return cg;
}
/* Free a consumer group and all its associated data. */
void streamFreeCG(streamCG *cg) {
raxFreeWithCallback(cg->pel,(void(*)(void*))streamFreeNACK);
raxFreeWithCallback(cg->consumers,(void(*)(void*))streamFreeConsumer);
zfree(cg);
}
/* Lookup the consumer group in the specified stream and returns its
* pointer, otherwise if there is no such group, NULL is returned. */
streamCG *streamLookupCG(stream *s, sds groupname) {
if (s->cgroups == NULL) return NULL;
void *cg = NULL;
raxFind(s->cgroups,(unsigned char*)groupname,sdslen(groupname),&cg);
return cg;
}
/* Create a consumer with the specified name in the group 'cg' and return.
* If the consumer exists, return NULL. As a side effect, when the consumer
* is successfully created, the key space will be notified and dirty++ unless
* the SCC_NO_NOTIFY or SCC_NO_DIRTIFY flags is specified. */
streamConsumer *streamCreateConsumer(streamCG *cg, sds name, robj *key, int dbid, int flags) {
if (cg == NULL) return NULL;
int notify = !(flags & SCC_NO_NOTIFY);
int dirty = !(flags & SCC_NO_DIRTIFY);
streamConsumer *consumer = zmalloc(sizeof(*consumer));
int success = raxTryInsert(cg->consumers,(unsigned char*)name,
sdslen(name),consumer,NULL);
if (!success) {
zfree(consumer);
return NULL;
}
consumer->name = sdsdup(name);
consumer->pel = raxNew();
consumer->active_time = -1;
consumer->seen_time = commandTimeSnapshot();
if (dirty) server.dirty++;
if (notify) notifyKeyspaceEvent(NOTIFY_STREAM,"xgroup-createconsumer",key,dbid);
return consumer;
}
/* Lookup the consumer with the specified name in the group 'cg'. */
streamConsumer *streamLookupConsumer(streamCG *cg, sds name) {
if (cg == NULL) return NULL;
void *consumer = NULL;
raxFind(cg->consumers,(unsigned char*)name,sdslen(name),&consumer);
return consumer;
}
/* Delete the consumer specified in the consumer group 'cg'. */
void streamDelConsumer(streamCG *cg, streamConsumer *consumer) {
/* Iterate all the consumer pending messages, deleting every corresponding
* entry from the global entry. */
raxIterator ri;
raxStart(&ri,consumer->pel);
raxSeek(&ri,"^",NULL,0);
while(raxNext(&ri)) {
streamNACK *nack = ri.data;
raxRemove(cg->pel,ri.key,ri.key_len,NULL);
streamFreeNACK(nack);
}
raxStop(&ri);
/* Deallocate the consumer. */
raxRemove(cg->consumers,(unsigned char*)consumer->name,
sdslen(consumer->name),NULL);
streamFreeConsumer(consumer);
}
/* -----------------------------------------------------------------------
* Consumer groups commands
* ----------------------------------------------------------------------- */
/* XGROUP CREATE <key> <groupname> <id or $> [MKSTREAM] [ENTRIESREAD entries_read]
* XGROUP SETID <key> <groupname> <id or $> [ENTRIESREAD entries_read]
* XGROUP DESTROY <key> <groupname>
* XGROUP CREATECONSUMER <key> <groupname> <consumer>
* XGROUP DELCONSUMER <key> <groupname> <consumername> */
void xgroupCommand(client *c) {
stream *s = NULL;
sds grpname = NULL;
streamCG *cg = NULL;
char *opt = c->argv[1]->ptr; /* Subcommand name. */
int mkstream = 0;
long long entries_read = SCG_INVALID_ENTRIES_READ;
robj *o;
/* Everything but the "HELP" option requires a key and group name. */
if (c->argc >= 4) {
/* Parse optional arguments for CREATE and SETID */
int i = 5;
int create_subcmd = !strcasecmp(opt,"CREATE");
int setid_subcmd = !strcasecmp(opt,"SETID");
while (i < c->argc) {
if (create_subcmd && !strcasecmp(c->argv[i]->ptr,"MKSTREAM")) {
mkstream = 1;
i++;
} else if ((create_subcmd || setid_subcmd) && !strcasecmp(c->argv[i]->ptr,"ENTRIESREAD") && i + 1 < c->argc) {
if (getLongLongFromObjectOrReply(c,c->argv[i+1],&entries_read,NULL) != C_OK)
return;
if (entries_read < 0 && entries_read != SCG_INVALID_ENTRIES_READ) {
addReplyError(c,"value for ENTRIESREAD must be positive or -1");
return;
}
i += 2;
} else {
addReplySubcommandSyntaxError(c);
return;
}
}
o = lookupKeyWrite(c->db,c->argv[2]);
if (o) {
if (checkType(c,o,OBJ_STREAM)) return;
s = o->ptr;
}
grpname = c->argv[3]->ptr;
}
/* Check for missing key/group. */
if (c->argc >= 4 && !mkstream) {
/* At this point key must exist, or there is an error. */
if (s == NULL) {
addReplyError(c,
"The XGROUP subcommand requires the key to exist. "
"Note that for CREATE you may want to use the MKSTREAM "
"option to create an empty stream automatically.");
return;
}
/* Certain subcommands require the group to exist. */
if ((cg = streamLookupCG(s,grpname)) == NULL &&
(!strcasecmp(opt,"SETID") ||
!strcasecmp(opt,"CREATECONSUMER") ||
!strcasecmp(opt,"DELCONSUMER")))
{
addReplyErrorFormat(c, "-NOGROUP No such consumer group '%s' "
"for key name '%s'",
(char*)grpname, (char*)c->argv[2]->ptr);
return;
}
}
/* Dispatch the different subcommands. */
if (c->argc == 2 && !strcasecmp(opt,"HELP")) {
const char *help[] = {
"CREATE <key> <groupname> <id|$> [option]",
" Create a new consumer group. Options are:",
" * MKSTREAM",
" Create the empty stream if it does not exist.",
" * ENTRIESREAD entries_read",
" Set the group's entries_read counter (internal use).",
"CREATECONSUMER <key> <groupname> <consumer>",
" Create a new consumer in the specified group.",
"DELCONSUMER <key> <groupname> <consumer>",
" Remove the specified consumer.",
"DESTROY <key> <groupname>",
" Remove the specified group.",
"SETID <key> <groupname> <id|$> [ENTRIESREAD entries_read]",
" Set the current group ID and entries_read counter.",
NULL
};
addReplyHelp(c, help);
} else if (!strcasecmp(opt,"CREATE") && (c->argc >= 5 && c->argc <= 8)) {
streamID id;
if (!strcmp(c->argv[4]->ptr,"$")) {
if (s) {
id = s->last_id;
} else {
id.ms = 0;
id.seq = 0;
}
} else if (streamParseStrictIDOrReply(c,c->argv[4],&id,0,NULL) != C_OK) {
return;
}
/* Handle the MKSTREAM option now that the command can no longer fail. */
if (s == NULL) {
serverAssert(mkstream);
o = createStreamObject();
dbAdd(c->db,c->argv[2],o);
s = o->ptr;
signalModifiedKey(c,c->db,c->argv[2]);
}
streamCG *cg = streamCreateCG(s,grpname,sdslen(grpname),&id,entries_read);
if (cg) {
addReply(c,shared.ok);
server.dirty++;
notifyKeyspaceEvent(NOTIFY_STREAM,"xgroup-create",
c->argv[2],c->db->id);
} else {
addReplyError(c,"-BUSYGROUP Consumer Group name already exists");
}
} else if (!strcasecmp(opt,"SETID") && (c->argc == 5 || c->argc == 7)) {
streamID id;
if (!strcmp(c->argv[4]->ptr,"$")) {
id = s->last_id;
} else if (streamParseIDOrReply(c,c->argv[4],&id,0) != C_OK) {
return;
}
cg->last_id = id;
cg->entries_read = entries_read;
addReply(c,shared.ok);
server.dirty++;
notifyKeyspaceEvent(NOTIFY_STREAM,"xgroup-setid",c->argv[2],c->db->id);
} else if (!strcasecmp(opt,"DESTROY") && c->argc == 4) {
if (cg) {
raxRemove(s->cgroups,(unsigned char*)grpname,sdslen(grpname),NULL);
streamFreeCG(cg);
addReply(c,shared.cone);
server.dirty++;
notifyKeyspaceEvent(NOTIFY_STREAM,"xgroup-destroy",
c->argv[2],c->db->id);
/* We want to unblock any XREADGROUP consumers with -NOGROUP. */
signalKeyAsReady(c->db,c->argv[2],OBJ_STREAM);
} else {
addReply(c,shared.czero);
}
} else if (!strcasecmp(opt,"CREATECONSUMER") && c->argc == 5) {
streamConsumer *created = streamCreateConsumer(cg,c->argv[4]->ptr,c->argv[2],
c->db->id,SCC_DEFAULT);
addReplyLongLong(c,created ? 1 : 0);
} else if (!strcasecmp(opt,"DELCONSUMER") && c->argc == 5) {
long long pending = 0;
streamConsumer *consumer = streamLookupConsumer(cg,c->argv[4]->ptr);
if (consumer) {
/* Delete the consumer and returns the number of pending messages
* that were yet associated with such a consumer. */
pending = raxSize(consumer->pel);
streamDelConsumer(cg,consumer);
server.dirty++;
notifyKeyspaceEvent(NOTIFY_STREAM,"xgroup-delconsumer",
c->argv[2],c->db->id);
}
addReplyLongLong(c,pending);
} else {
addReplySubcommandSyntaxError(c);
}
}
/* XSETID <stream> <id> [ENTRIESADDED entries_added] [MAXDELETEDID max_deleted_entry_id]
*
* Set the internal "last ID", "added entries" and "maximal deleted entry ID"
* of a stream. */
void xsetidCommand(client *c) {
streamID id, max_xdel_id = {0, 0};
long long entries_added = -1;
if (streamParseStrictIDOrReply(c,c->argv[2],&id,0,NULL) != C_OK)
return;
int i = 3;
while (i < c->argc) {
int moreargs = (c->argc-1) - i; /* Number of additional arguments. */
char *opt = c->argv[i]->ptr;
if (!strcasecmp(opt,"ENTRIESADDED") && moreargs) {
if (getLongLongFromObjectOrReply(c,c->argv[i+1],&entries_added,NULL) != C_OK) {
return;
} else if (entries_added < 0) {
addReplyError(c,"entries_added must be positive");
return;
}
i += 2;
} else if (!strcasecmp(opt,"MAXDELETEDID") && moreargs) {
if (streamParseStrictIDOrReply(c,c->argv[i+1],&max_xdel_id,0,NULL) != C_OK) {
return;
} else if (streamCompareID(&id,&max_xdel_id) < 0) {
addReplyError(c,"The ID specified in XSETID is smaller than the provided max_deleted_entry_id");
return;
}
i += 2;
} else {
addReplyErrorObject(c,shared.syntaxerr);
return;
}
}
robj *o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr);
if (o == NULL || checkType(c,o,OBJ_STREAM)) return;
stream *s = o->ptr;
if (streamCompareID(&id,&s->max_deleted_entry_id) < 0) {
addReplyError(c,"The ID specified in XSETID is smaller than current max_deleted_entry_id");
return;
}
/* If the stream has at least one item, we want to check that the user
* is setting a last ID that is equal or greater than the current top
* item, otherwise the fundamental ID monotonicity assumption is violated. */
if (s->length > 0) {
streamID maxid;
streamLastValidID(s,&maxid);
if (streamCompareID(&id,&maxid) < 0) {
addReplyError(c,"The ID specified in XSETID is smaller than the target stream top item");
return;
}
/* If an entries_added was provided, it can't be lower than the length. */
if (entries_added != -1 && s->length > (uint64_t)entries_added) {
addReplyError(c,"The entries_added specified in XSETID is smaller than the target stream length");
return;
}
}
s->last_id = id;
if (entries_added != -1)
s->entries_added = entries_added;
if (!streamIDEqZero(&max_xdel_id))
s->max_deleted_entry_id = max_xdel_id;
addReply(c,shared.ok);
server.dirty++;
notifyKeyspaceEvent(NOTIFY_STREAM,"xsetid",c->argv[1],c->db->id);
}
/* XACK <key> <group> <id> <id> ... <id>
* Acknowledge a message as processed. In practical terms we just check the
* pending entries list (PEL) of the group, and delete the PEL entry both from
* the group and the consumer (pending messages are referenced in both places).
*
* Return value of the command is the number of messages successfully
* acknowledged, that is, the IDs we were actually able to resolve in the PEL.
*/
void xackCommand(client *c) {
streamCG *group = NULL;
robj *o = lookupKeyRead(c->db,c->argv[1]);
if (o) {
if (checkType(c,o,OBJ_STREAM)) return; /* Type error. */
group = streamLookupCG(o->ptr,c->argv[2]->ptr);
}
/* No key or group? Nothing to ack. */
if (o == NULL || group == NULL) {
addReply(c,shared.czero);
return;
}
/* Start parsing the IDs, so that we abort ASAP if there is a syntax
* error: the return value of this command cannot be an error in case
* the client successfully acknowledged some messages, so it should be
* executed in a "all or nothing" fashion. */
streamID static_ids[STREAMID_STATIC_VECTOR_LEN];
streamID *ids = static_ids;
int id_count = c->argc-3;
if (id_count > STREAMID_STATIC_VECTOR_LEN)
ids = zmalloc(sizeof(streamID)*id_count);
for (int j = 3; j < c->argc; j++) {
if (streamParseStrictIDOrReply(c,c->argv[j],&ids[j-3],0,NULL) != C_OK) goto cleanup;
}
int acknowledged = 0;
for (int j = 3; j < c->argc; j++) {
unsigned char buf[sizeof(streamID)];
streamEncodeID(buf,&ids[j-3]);
/* Lookup the ID in the group PEL: it will have a reference to the
* NACK structure that will have a reference to the consumer, so that
* we are able to remove the entry from both PELs. */
void *result;
if (raxFind(group->pel,buf,sizeof(buf),&result)) {
streamNACK *nack = result;
raxRemove(group->pel,buf,sizeof(buf),NULL);
raxRemove(nack->consumer->pel,buf,sizeof(buf),NULL);
streamFreeNACK(nack);
acknowledged++;
server.dirty++;
}
}
addReplyLongLong(c,acknowledged);
cleanup:
if (ids != static_ids) zfree(ids);
}
/* XPENDING <key> <group> [[IDLE <idle>] <start> <stop> <count> [<consumer>]]
*
* If start and stop are omitted, the command just outputs information about
* the amount of pending messages for the key/group pair, together with
* the minimum and maximum ID of pending messages.
*
* If start and stop are provided instead, the pending messages are returned
* with information about the current owner, number of deliveries and last
* delivery time and so forth. */
void xpendingCommand(client *c) {
int justinfo = c->argc == 3; /* Without the range just outputs general
information about the PEL. */
robj *key = c->argv[1];
robj *groupname = c->argv[2];
robj *consumername = NULL;
streamID startid, endid;
long long count = 0;
long long minidle = 0;
int startex = 0, endex = 0;
/* Start and stop, and the consumer, can be omitted. Also the IDLE modifier. */
if (c->argc != 3 && (c->argc < 6 || c->argc > 9)) {
addReplyErrorObject(c,shared.syntaxerr);
return;
}
/* Parse start/end/count arguments ASAP if needed, in order to report
* syntax errors before any other error. */
if (c->argc >= 6) {
int startidx = 3; /* Without IDLE */
if (!strcasecmp(c->argv[3]->ptr, "IDLE")) {
if (getLongLongFromObjectOrReply(c, c->argv[4], &minidle, NULL) == C_ERR)
return;
if (c->argc < 8) {
/* If IDLE was provided we must have at least 'start end count' */
addReplyErrorObject(c,shared.syntaxerr);
return;
}
/* Search for rest of arguments after 'IDLE <idle>' */
startidx += 2;
}
/* count argument. */
if (getLongLongFromObjectOrReply(c,c->argv[startidx+2],&count,NULL) == C_ERR)
return;
if (count < 0) count = 0;
/* start and end arguments. */
if (streamParseIntervalIDOrReply(c,c->argv[startidx],&startid,&startex,0) != C_OK)
return;
if (startex && streamIncrID(&startid) != C_OK) {
addReplyError(c,"invalid start ID for the interval");
return;
}
if (streamParseIntervalIDOrReply(c,c->argv[startidx+1],&endid,&endex,UINT64_MAX) != C_OK)
return;
if (endex && streamDecrID(&endid) != C_OK) {
addReplyError(c,"invalid end ID for the interval");
return;
}
if (startidx+3 < c->argc) {
/* 'consumer' was provided */
consumername = c->argv[startidx+3];
}
}
/* Lookup the key and the group inside the stream. */
robj *o = lookupKeyRead(c->db,c->argv[1]);
streamCG *group;
if (checkType(c,o,OBJ_STREAM)) return;
if (o == NULL ||
(group = streamLookupCG(o->ptr,groupname->ptr)) == NULL)
{
addReplyErrorFormat(c, "-NOGROUP No such key '%s' or consumer "
"group '%s'",
(char*)key->ptr,(char*)groupname->ptr);
return;
}
/* XPENDING <key> <group> variant. */
if (justinfo) {
addReplyArrayLen(c,4);
/* Total number of messages in the PEL. */
addReplyLongLong(c,raxSize(group->pel));
/* First and last IDs. */
if (raxSize(group->pel) == 0) {
addReplyNull(c); /* Start. */
addReplyNull(c); /* End. */
addReplyNullArray(c); /* Clients. */
} else {
/* Start. */
raxIterator ri;
raxStart(&ri,group->pel);
raxSeek(&ri,"^",NULL,0);
raxNext(&ri);
streamDecodeID(ri.key,&startid);
addReplyStreamID(c,&startid);
/* End. */
raxSeek(&ri,"$",NULL,0);
raxNext(&ri);
streamDecodeID(ri.key,&endid);
addReplyStreamID(c,&endid);
raxStop(&ri);
/* Consumers with pending messages. */
raxStart(&ri,group->consumers);
raxSeek(&ri,"^",NULL,0);
void *arraylen_ptr = addReplyDeferredLen(c);
size_t arraylen = 0;
while(raxNext(&ri)) {
streamConsumer *consumer = ri.data;
if (raxSize(consumer->pel) == 0) continue;
addReplyArrayLen(c,2);
addReplyBulkCBuffer(c,ri.key,ri.key_len);
addReplyBulkLongLong(c,raxSize(consumer->pel));
arraylen++;
}
setDeferredArrayLen(c,arraylen_ptr,arraylen);
raxStop(&ri);
}
} else { /* <start>, <stop> and <count> provided, return actual pending entries (not just info) */
streamConsumer *consumer = NULL;
if (consumername) {
consumer = streamLookupConsumer(group,consumername->ptr);
/* If a consumer name was mentioned but it does not exist, we can
* just return an empty array. */
if (consumer == NULL) {
addReplyArrayLen(c,0);
return;
}
}
rax *pel = consumer ? consumer->pel : group->pel;
unsigned char startkey[sizeof(streamID)];
unsigned char endkey[sizeof(streamID)];
raxIterator ri;
mstime_t now = commandTimeSnapshot();
streamEncodeID(startkey,&startid);
streamEncodeID(endkey,&endid);
raxStart(&ri,pel);
raxSeek(&ri,">=",startkey,sizeof(startkey));
void *arraylen_ptr = addReplyDeferredLen(c);
size_t arraylen = 0;
while(count && raxNext(&ri) && memcmp(ri.key,endkey,ri.key_len) <= 0) {
streamNACK *nack = ri.data;
if (minidle) {
mstime_t this_idle = now - nack->delivery_time;
if (this_idle < minidle) continue;
}
arraylen++;
count--;
addReplyArrayLen(c,4);
/* Entry ID. */
streamID id;
streamDecodeID(ri.key,&id);
addReplyStreamID(c,&id);
/* Consumer name. */
addReplyBulkCBuffer(c,nack->consumer->name,
sdslen(nack->consumer->name));
/* Milliseconds elapsed since last delivery. */
mstime_t elapsed = now - nack->delivery_time;
if (elapsed < 0) elapsed = 0;
addReplyLongLong(c,elapsed);
/* Number of deliveries. */
addReplyLongLong(c,nack->delivery_count);
}
raxStop(&ri);
setDeferredArrayLen(c,arraylen_ptr,arraylen);
}
}
/* XCLAIM <key> <group> <consumer> <min-idle-time> <ID-1> <ID-2>
* [IDLE <milliseconds>] [TIME <mstime>] [RETRYCOUNT <count>]
* [FORCE] [JUSTID]
*
* Changes ownership of one or multiple messages in the Pending Entries List
* of a given stream consumer group.
*
* If the message ID (among the specified ones) exists, and its idle
* time greater or equal to <min-idle-time>, then the message new owner
* becomes the specified <consumer>. If the minimum idle time specified
* is zero, messages are claimed regardless of their idle time.
*
* All the messages that cannot be found inside the pending entries list
* are ignored, but in case the FORCE option is used. In that case we
* create the NACK (representing a not yet acknowledged message) entry in
* the consumer group PEL.
*
* This command creates the consumer as side effect if it does not yet
* exists. Moreover the command reset the idle time of the message to 0,
* even if by using the IDLE or TIME options, the user can control the
* new idle time.
*
* The options at the end can be used in order to specify more attributes
* to set in the representation of the pending message:
*
* 1. IDLE <ms>:
* Set the idle time (last time it was delivered) of the message.
* If IDLE is not specified, an IDLE of 0 is assumed, that is,
* the time count is reset because the message has now a new
* owner trying to process it.
*
* 2. TIME <ms-unix-time>:
* This is the same as IDLE but instead of a relative amount of
* milliseconds, it sets the idle time to a specific unix time
* (in milliseconds). This is useful in order to rewrite the AOF
* file generating XCLAIM commands.
*
* 3. RETRYCOUNT <count>:
* Set the retry counter to the specified value. This counter is
* incremented every time a message is delivered again. Normally
* XCLAIM does not alter this counter, which is just served to clients
* when the XPENDING command is called: this way clients can detect
* anomalies, like messages that are never processed for some reason
* after a big number of delivery attempts.
*
* 4. FORCE:
* Creates the pending message entry in the PEL even if certain
* specified IDs are not already in the PEL assigned to a different
* client. However the message must be exist in the stream, otherwise
* the IDs of non existing messages are ignored.
*
* 5. JUSTID:
* Return just an array of IDs of messages successfully claimed,
* without returning the actual message.
*
* 6. LASTID <id>:
* Update the consumer group last ID with the specified ID if the
* current last ID is smaller than the provided one.
* This is used for replication / AOF, so that when we read from a
* consumer group, the XCLAIM that gets propagated to give ownership
* to the consumer, is also used in order to update the group current
* ID.
*
* The command returns an array of messages that the user
* successfully claimed, so that the caller is able to understand
* what messages it is now in charge of. */
void xclaimCommand(client *c) {
streamCG *group = NULL;
robj *o = lookupKeyRead(c->db,c->argv[1]);
long long minidle; /* Minimum idle time argument. */
long long retrycount = -1; /* -1 means RETRYCOUNT option not given. */
mstime_t deliverytime = -1; /* -1 means IDLE/TIME options not given. */
int force = 0;
int justid = 0;
if (o) {
if (checkType(c,o,OBJ_STREAM)) return; /* Type error. */
group = streamLookupCG(o->ptr,c->argv[2]->ptr);
}
/* No key or group? Send an error given that the group creation
* is mandatory. */
if (o == NULL || group == NULL) {
addReplyErrorFormat(c,"-NOGROUP No such key '%s' or "
"consumer group '%s'", (char*)c->argv[1]->ptr,
(char*)c->argv[2]->ptr);
return;
}
if (getLongLongFromObjectOrReply(c,c->argv[4],&minidle,
"Invalid min-idle-time argument for XCLAIM")
!= C_OK) return;
if (minidle < 0) minidle = 0;
/* Start parsing the IDs, so that we abort ASAP if there is a syntax
* error: the return value of this command cannot be an error in case
* the client successfully claimed some message, so it should be
* executed in a "all or nothing" fashion. */
int j;
streamID static_ids[STREAMID_STATIC_VECTOR_LEN];
streamID *ids = static_ids;
int id_count = c->argc-5;
if (id_count > STREAMID_STATIC_VECTOR_LEN)
ids = zmalloc(sizeof(streamID)*id_count);
for (j = 5; j < c->argc; j++) {
if (streamParseStrictIDOrReply(NULL,c->argv[j],&ids[j-5],0,NULL) != C_OK) break;
}
int last_id_arg = j-1; /* Next time we iterate the IDs we now the range. */
/* If we stopped because some IDs cannot be parsed, perhaps they
* are trailing options. */
mstime_t now = commandTimeSnapshot();
streamID last_id = {0,0};
int propagate_last_id = 0;
for (; j < c->argc; j++) {
int moreargs = (c->argc-1) - j; /* Number of additional arguments. */
char *opt = c->argv[j]->ptr;
if (!strcasecmp(opt,"FORCE")) {
force = 1;
} else if (!strcasecmp(opt,"JUSTID")) {
justid = 1;
} else if (!strcasecmp(opt,"IDLE") && moreargs) {
j++;
if (getLongLongFromObjectOrReply(c,c->argv[j],&deliverytime,
"Invalid IDLE option argument for XCLAIM")
!= C_OK) goto cleanup;
deliverytime = now - deliverytime;
} else if (!strcasecmp(opt,"TIME") && moreargs) {
j++;
if (getLongLongFromObjectOrReply(c,c->argv[j],&deliverytime,
"Invalid TIME option argument for XCLAIM")
!= C_OK) goto cleanup;
} else if (!strcasecmp(opt,"RETRYCOUNT") && moreargs) {
j++;
if (getLongLongFromObjectOrReply(c,c->argv[j],&retrycount,
"Invalid RETRYCOUNT option argument for XCLAIM")
!= C_OK) goto cleanup;
} else if (!strcasecmp(opt,"LASTID") && moreargs) {
j++;
if (streamParseStrictIDOrReply(c,c->argv[j],&last_id,0,NULL) != C_OK) goto cleanup;
} else {
addReplyErrorFormat(c,"Unrecognized XCLAIM option '%s'",opt);
goto cleanup;
}
}
if (streamCompareID(&last_id,&group->last_id) > 0) {
group->last_id = last_id;
propagate_last_id = 1;
}
if (deliverytime != -1) {
/* If a delivery time was passed, either with IDLE or TIME, we
* do some sanity check on it, and set the deliverytime to now
* (which is a sane choice usually) if the value is bogus.
* To raise an error here is not wise because clients may compute
* the idle time doing some math starting from their local time,
* and this is not a good excuse to fail in case, for instance,
* the computer time is a bit in the future from our POV. */
if (deliverytime < 0 || deliverytime > now) deliverytime = now;
} else {
/* If no IDLE/TIME option was passed, we want the last delivery
* time to be now, so that the idle time of the message will be
* zero. */
deliverytime = now;
}
/* Do the actual claiming. */
streamConsumer *consumer = streamLookupConsumer(group,c->argv[3]->ptr);
if (consumer == NULL) {
consumer = streamCreateConsumer(group,c->argv[3]->ptr,c->argv[1],c->db->id,SCC_DEFAULT);
}
consumer->seen_time = commandTimeSnapshot();
void *arraylenptr = addReplyDeferredLen(c);
size_t arraylen = 0;
for (int j = 5; j <= last_id_arg; j++) {
streamID id = ids[j-5];
unsigned char buf[sizeof(streamID)];
streamEncodeID(buf,&id);
/* Lookup the ID in the group PEL. */
void *result = NULL;
raxFind(group->pel,buf,sizeof(buf),&result);
streamNACK *nack = result;
/* Item must exist for us to transfer it to another consumer. */
if (!streamEntryExists(o->ptr,&id)) {
/* Clear this entry from the PEL, it no longer exists */
if (nack != NULL) {
/* Propagate this change (we are going to delete the NACK). */
streamPropagateXCLAIM(c,c->argv[1],group,c->argv[2],c->argv[j],nack);
propagate_last_id = 0; /* Will be propagated by XCLAIM itself. */
server.dirty++;
/* Release the NACK */
raxRemove(group->pel,buf,sizeof(buf),NULL);
raxRemove(nack->consumer->pel,buf,sizeof(buf),NULL);
streamFreeNACK(nack);
}
continue;
}
/* If FORCE is passed, let's check if at least the entry
* exists in the Stream. In such case, we'll create a new
* entry in the PEL from scratch, so that XCLAIM can also
* be used to create entries in the PEL. Useful for AOF
* and replication of consumer groups. */
if (force && nack == NULL) {
/* Create the NACK. */
nack = streamCreateNACK(NULL);
raxInsert(group->pel,buf,sizeof(buf),nack,NULL);
}
if (nack != NULL) {
/* We need to check if the minimum idle time requested
* by the caller is satisfied by this entry.
*
* Note that the nack could be created by FORCE, in this
* case there was no pre-existing entry and minidle should
* be ignored, but in that case nack->consumer is NULL. */
if (nack->consumer && minidle) {
mstime_t this_idle = now - nack->delivery_time;
if (this_idle < minidle) continue;
}
if (nack->consumer != consumer) {
/* Remove the entry from the old consumer.
* Note that nack->consumer is NULL if we created the
* NACK above because of the FORCE option. */
if (nack->consumer)
raxRemove(nack->consumer->pel,buf,sizeof(buf),NULL);
}
nack->delivery_time = deliverytime;
/* Set the delivery attempts counter if given, otherwise
* autoincrement unless JUSTID option provided */
if (retrycount >= 0) {
nack->delivery_count = retrycount;
} else if (!justid) {
nack->delivery_count++;
}
if (nack->consumer != consumer) {
/* Add the entry in the new consumer local PEL. */
raxInsert(consumer->pel,buf,sizeof(buf),nack,NULL);
nack->consumer = consumer;
}
/* Send the reply for this entry. */
if (justid) {
addReplyStreamID(c,&id);
} else {
serverAssert(streamReplyWithRange(c,o->ptr,&id,&id,1,0,NULL,NULL,STREAM_RWR_RAWENTRIES,NULL) == 1);
}
arraylen++;
consumer->active_time = commandTimeSnapshot();
/* Propagate this change. */
streamPropagateXCLAIM(c,c->argv[1],group,c->argv[2],c->argv[j],nack);
propagate_last_id = 0; /* Will be propagated by XCLAIM itself. */
server.dirty++;
}
}
if (propagate_last_id) {
streamPropagateGroupID(c,c->argv[1],group,c->argv[2]);
server.dirty++;
}
setDeferredArrayLen(c,arraylenptr,arraylen);
preventCommandPropagation(c);
cleanup:
if (ids != static_ids) zfree(ids);
}
/* XAUTOCLAIM <key> <group> <consumer> <min-idle-time> <start> [COUNT <count>] [JUSTID]
*
* Changes ownership of one or multiple messages in the Pending Entries List
* of a given stream consumer group.
*
* For each PEL entry, if its idle time greater or equal to <min-idle-time>,
* then the message new owner becomes the specified <consumer>.
* If the minimum idle time specified is zero, messages are claimed
* regardless of their idle time.
*
* This command creates the consumer as side effect if it does not yet
* exists. Moreover the command reset the idle time of the message to 0.
*
* The command returns an array of messages that the user
* successfully claimed, so that the caller is able to understand
* what messages it is now in charge of. */
void xautoclaimCommand(client *c) {
streamCG *group = NULL;
robj *o = lookupKeyRead(c->db,c->argv[1]);
long long minidle; /* Minimum idle time argument, in milliseconds. */
long count = 100; /* Maximum entries to claim. */
const unsigned attempts_factor = 10;
streamID startid;
int startex;
int justid = 0;
/* Parse idle/start/end/count arguments ASAP if needed, in order to report
* syntax errors before any other error. */
if (getLongLongFromObjectOrReply(c,c->argv[4],&minidle,"Invalid min-idle-time argument for XAUTOCLAIM") != C_OK)
return;
if (minidle < 0) minidle = 0;
if (streamParseIntervalIDOrReply(c,c->argv[5],&startid,&startex,0) != C_OK)
return;
if (startex && streamIncrID(&startid) != C_OK) {
addReplyError(c,"invalid start ID for the interval");
return;
}
int j = 6; /* options start at argv[6] */
while(j < c->argc) {
int moreargs = (c->argc-1) - j; /* Number of additional arguments. */
char *opt = c->argv[j]->ptr;
if (!strcasecmp(opt,"COUNT") && moreargs) {
long max_count = LONG_MAX / (max(sizeof(streamID), attempts_factor));
if (getRangeLongFromObjectOrReply(c,c->argv[j+1],1,max_count,&count,"COUNT must be > 0") != C_OK)
return;
j++;
} else if (!strcasecmp(opt,"JUSTID")) {
justid = 1;
} else {
addReplyErrorObject(c,shared.syntaxerr);
return;
}
j++;
}
if (o) {
if (checkType(c,o,OBJ_STREAM))
return; /* Type error. */
group = streamLookupCG(o->ptr,c->argv[2]->ptr);
}
/* No key or group? Send an error given that the group creation
* is mandatory. */
if (o == NULL || group == NULL) {
addReplyErrorFormat(c,"-NOGROUP No such key '%s' or consumer group '%s'",
(char*)c->argv[1]->ptr,
(char*)c->argv[2]->ptr);
return;
}
streamID *deleted_ids = ztrymalloc(count * sizeof(streamID));
if (!deleted_ids) {
addReplyError(c, "Insufficient memory, failed allocating transient memory, COUNT too high.");
return;
}
/* Do the actual claiming. */
streamConsumer *consumer = streamLookupConsumer(group,c->argv[3]->ptr);
if (consumer == NULL) {
consumer = streamCreateConsumer(group,c->argv[3]->ptr,c->argv[1],c->db->id,SCC_DEFAULT);
}
consumer->seen_time = commandTimeSnapshot();
long long attempts = count * attempts_factor;
addReplyArrayLen(c, 3); /* We add another reply later */
void *endidptr = addReplyDeferredLen(c); /* reply[0] */
void *arraylenptr = addReplyDeferredLen(c); /* reply[1] */
unsigned char startkey[sizeof(streamID)];
streamEncodeID(startkey,&startid);
raxIterator ri;
raxStart(&ri,group->pel);
raxSeek(&ri,">=",startkey,sizeof(startkey));
size_t arraylen = 0;
mstime_t now = commandTimeSnapshot();
int deleted_id_num = 0;
while (attempts-- && count && raxNext(&ri)) {
streamNACK *nack = ri.data;
streamID id;
streamDecodeID(ri.key, &id);
/* Item must exist for us to transfer it to another consumer. */
if (!streamEntryExists(o->ptr,&id)) {
/* Propagate this change (we are going to delete the NACK). */
robj *idstr = createObjectFromStreamID(&id);
streamPropagateXCLAIM(c,c->argv[1],group,c->argv[2],idstr,nack);
decrRefCount(idstr);
server.dirty++;
/* Clear this entry from the PEL, it no longer exists */
raxRemove(group->pel,ri.key,ri.key_len,NULL);
raxRemove(nack->consumer->pel,ri.key,ri.key_len,NULL);
streamFreeNACK(nack);
/* Remember the ID for later */
deleted_ids[deleted_id_num++] = id;
raxSeek(&ri,">=",ri.key,ri.key_len);
count--; /* Count is a limit of the command response size. */
continue;
}
if (minidle) {
mstime_t this_idle = now - nack->delivery_time;
if (this_idle < minidle)
continue;
}
if (nack->consumer != consumer) {
/* Remove the entry from the old consumer.
* Note that nack->consumer is NULL if we created the
* NACK above because of the FORCE option. */
if (nack->consumer)
raxRemove(nack->consumer->pel,ri.key,ri.key_len,NULL);
}
/* Update the consumer and idle time. */
nack->delivery_time = now;
/* Increment the delivery attempts counter unless JUSTID option provided */
if (!justid)
nack->delivery_count++;
if (nack->consumer != consumer) {
/* Add the entry in the new consumer local PEL. */
raxInsert(consumer->pel,ri.key,ri.key_len,nack,NULL);
nack->consumer = consumer;
}
/* Send the reply for this entry. */
if (justid) {
addReplyStreamID(c,&id);
} else {
serverAssert(streamReplyWithRange(c,o->ptr,&id,&id,1,0,NULL,NULL,STREAM_RWR_RAWENTRIES,NULL) == 1);
}
arraylen++;
count--;
consumer->active_time = commandTimeSnapshot();
/* Propagate this change. */
robj *idstr = createObjectFromStreamID(&id);
streamPropagateXCLAIM(c,c->argv[1],group,c->argv[2],idstr,nack);
decrRefCount(idstr);
server.dirty++;
}
/* We need to return the next entry as a cursor for the next XAUTOCLAIM call */
raxNext(&ri);
streamID endid;
if (raxEOF(&ri)) {
endid.ms = endid.seq = 0;
} else {
streamDecodeID(ri.key, &endid);
}
raxStop(&ri);
setDeferredArrayLen(c,arraylenptr,arraylen);
setDeferredReplyStreamID(c,endidptr,&endid);
addReplyArrayLen(c, deleted_id_num); /* reply[2] */
for (int i = 0; i < deleted_id_num; i++) {
addReplyStreamID(c, &deleted_ids[i]);
}
zfree(deleted_ids);
preventCommandPropagation(c);
}
/* XDEL <key> [<ID1> <ID2> ... <IDN>]
*
* Removes the specified entries from the stream. Returns the number
* of items actually deleted, that may be different from the number
* of IDs passed in case certain IDs do not exist. */
void xdelCommand(client *c) {
robj *o;
if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL
|| checkType(c,o,OBJ_STREAM)) return;
stream *s = o->ptr;
/* We need to sanity check the IDs passed to start. Even if not
* a big issue, it is not great that the command is only partially
* executed because at some point an invalid ID is parsed. */
streamID static_ids[STREAMID_STATIC_VECTOR_LEN];
streamID *ids = static_ids;
int id_count = c->argc-2;
if (id_count > STREAMID_STATIC_VECTOR_LEN)
ids = zmalloc(sizeof(streamID)*id_count);
for (int j = 2; j < c->argc; j++) {
if (streamParseStrictIDOrReply(c,c->argv[j],&ids[j-2],0,NULL) != C_OK) goto cleanup;
}
/* Actually apply the command. */
int deleted = 0;
int first_entry = 0;
for (int j = 2; j < c->argc; j++) {
streamID *id = &ids[j-2];
if (streamDeleteItem(s,id)) {
/* We want to know if the first entry in the stream was deleted
* so we can later set the new one. */
if (streamCompareID(id,&s->first_id) == 0) {
first_entry = 1;
}
/* Update the stream's maximal tombstone if needed. */
if (streamCompareID(id,&s->max_deleted_entry_id) > 0) {
s->max_deleted_entry_id = *id;
}
deleted++;
};
}
/* Update the stream's first ID. */
if (deleted) {
if (s->length == 0) {
s->first_id.ms = 0;
s->first_id.seq = 0;
} else if (first_entry) {
streamGetEdgeID(s,1,1,&s->first_id);
}
}
/* Propagate the write if needed. */
if (deleted) {
signalModifiedKey(c,c->db,c->argv[1]);
notifyKeyspaceEvent(NOTIFY_STREAM,"xdel",c->argv[1],c->db->id);
server.dirty += deleted;
}
addReplyLongLong(c,deleted);
cleanup:
if (ids != static_ids) zfree(ids);
}
/* General form: XTRIM <key> [... options ...]
*
* List of options:
*
* Trim strategies:
*
* MAXLEN [~|=] <count> -- Trim so that the stream will be capped at
* the specified length. Use ~ before the
* count in order to demand approximated trimming
* (like XADD MAXLEN option).
* MINID [~|=] <id> -- Trim so that the stream will not contain entries
* with IDs smaller than 'id'. Use ~ before the
* count in order to demand approximated trimming
* (like XADD MINID option).
*
* Other options:
*
* LIMIT <entries> -- The maximum number of entries to trim.
* 0 means unlimited. Unless specified, it is set
* to a default of 100*server.stream_node_max_entries,
* and that's in order to keep the trimming time sane.
* Has meaning only if `~` was provided.
*/
void xtrimCommand(client *c) {
robj *o;
/* Argument parsing. */
streamAddTrimArgs parsed_args;
if (streamParseAddOrTrimArgsOrReply(c, &parsed_args, 0) < 0)
return; /* streamParseAddOrTrimArgsOrReply already replied. */
/* If the key does not exist, we are ok returning zero, that is, the
* number of elements removed from the stream. */
if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL
|| checkType(c,o,OBJ_STREAM)) return;
stream *s = o->ptr;
/* Perform the trimming. */
int64_t deleted = streamTrim(s, &parsed_args);
if (deleted) {
notifyKeyspaceEvent(NOTIFY_STREAM,"xtrim",c->argv[1],c->db->id);
if (parsed_args.approx_trim) {
/* In case our trimming was limited (by LIMIT or by ~) we must
* re-write the relevant trim argument to make sure there will be
* no inconsistencies in AOF loading or in the replica.
* It's enough to check only args->approx because there is no
* way LIMIT is given without the ~ option. */
streamRewriteApproxSpecifier(c,parsed_args.trim_strategy_arg_idx-1);
streamRewriteTrimArgument(c,s,parsed_args.trim_strategy,parsed_args.trim_strategy_arg_idx);
}
/* Propagate the write. */
signalModifiedKey(c, c->db,c->argv[1]);
server.dirty += deleted;
}
addReplyLongLong(c,deleted);
}
/* Helper function for xinfoCommand.
* Handles the variants of XINFO STREAM */
void xinfoReplyWithStreamInfo(client *c, stream *s) {
int full = 1;
long long count = 10; /* Default COUNT is 10 so we don't block the server */
robj **optv = c->argv + 3; /* Options start after XINFO STREAM <key> */
int optc = c->argc - 3;
/* Parse options. */
if (optc == 0) {
full = 0;
} else {
/* Valid options are [FULL] or [FULL COUNT <count>] */
if (optc != 1 && optc != 3) {
addReplySubcommandSyntaxError(c);
return;
}
/* First option must be "FULL" */
if (strcasecmp(optv[0]->ptr,"full")) {
addReplySubcommandSyntaxError(c);
return;
}
if (optc == 3) {
/* First option must be "FULL" */
if (strcasecmp(optv[1]->ptr,"count")) {
addReplySubcommandSyntaxError(c);
return;
}
if (getLongLongFromObjectOrReply(c,optv[2],&count,NULL) == C_ERR)
return;
if (count < 0) count = 10;
}
}
addReplyMapLen(c,full ? 9 : 10);
addReplyBulkCString(c,"length");
addReplyLongLong(c,s->length);
addReplyBulkCString(c,"radix-tree-keys");
addReplyLongLong(c,raxSize(s->rax));
addReplyBulkCString(c,"radix-tree-nodes");
addReplyLongLong(c,s->rax->numnodes);
addReplyBulkCString(c,"last-generated-id");
addReplyStreamID(c,&s->last_id);
addReplyBulkCString(c,"max-deleted-entry-id");
addReplyStreamID(c,&s->max_deleted_entry_id);
addReplyBulkCString(c,"entries-added");
addReplyLongLong(c,s->entries_added);
addReplyBulkCString(c,"recorded-first-entry-id");
addReplyStreamID(c,&s->first_id);
if (!full) {
/* XINFO STREAM <key> */
addReplyBulkCString(c,"groups");
addReplyLongLong(c,s->cgroups ? raxSize(s->cgroups) : 0);
/* To emit the first/last entry we use streamReplyWithRange(). */
int emitted;
streamID start, end;
start.ms = start.seq = 0;
end.ms = end.seq = UINT64_MAX;
addReplyBulkCString(c,"first-entry");
emitted = streamReplyWithRange(c,s,&start,&end,1,0,NULL,NULL,
STREAM_RWR_RAWENTRIES,NULL);
if (!emitted) addReplyNull(c);
addReplyBulkCString(c,"last-entry");
emitted = streamReplyWithRange(c,s,&start,&end,1,1,NULL,NULL,
STREAM_RWR_RAWENTRIES,NULL);
if (!emitted) addReplyNull(c);
} else {
/* XINFO STREAM <key> FULL [COUNT <count>] */
/* Stream entries */
addReplyBulkCString(c,"entries");
streamReplyWithRange(c,s,NULL,NULL,count,0,NULL,NULL,0,NULL);
/* Consumer groups */
addReplyBulkCString(c,"groups");
if (s->cgroups == NULL) {
addReplyArrayLen(c,0);
} else {
addReplyArrayLen(c,raxSize(s->cgroups));
raxIterator ri_cgroups;
raxStart(&ri_cgroups,s->cgroups);
raxSeek(&ri_cgroups,"^",NULL,0);
while(raxNext(&ri_cgroups)) {
streamCG *cg = ri_cgroups.data;
addReplyMapLen(c,7);
/* Name */
addReplyBulkCString(c,"name");
addReplyBulkCBuffer(c,ri_cgroups.key,ri_cgroups.key_len);
/* Last delivered ID */
addReplyBulkCString(c,"last-delivered-id");
addReplyStreamID(c,&cg->last_id);
/* Read counter of the last delivered ID */
addReplyBulkCString(c,"entries-read");
if (cg->entries_read != SCG_INVALID_ENTRIES_READ) {
addReplyLongLong(c,cg->entries_read);
} else {
addReplyNull(c);
}
/* Group lag */
addReplyBulkCString(c,"lag");
streamReplyWithCGLag(c,s,cg);
/* Group PEL count */
addReplyBulkCString(c,"pel-count");
addReplyLongLong(c,raxSize(cg->pel));
/* Group PEL */
addReplyBulkCString(c,"pending");
long long arraylen_cg_pel = 0;
void *arrayptr_cg_pel = addReplyDeferredLen(c);
raxIterator ri_cg_pel;
raxStart(&ri_cg_pel,cg->pel);
raxSeek(&ri_cg_pel,"^",NULL,0);
while(raxNext(&ri_cg_pel) && (!count || arraylen_cg_pel < count)) {
streamNACK *nack = ri_cg_pel.data;
addReplyArrayLen(c,4);
/* Entry ID. */
streamID id;
streamDecodeID(ri_cg_pel.key,&id);
addReplyStreamID(c,&id);
/* Consumer name. */
serverAssert(nack->consumer); /* assertion for valgrind (avoid NPD) */
addReplyBulkCBuffer(c,nack->consumer->name,
sdslen(nack->consumer->name));
/* Last delivery. */
addReplyLongLong(c,nack->delivery_time);
/* Number of deliveries. */
addReplyLongLong(c,nack->delivery_count);
arraylen_cg_pel++;
}
setDeferredArrayLen(c,arrayptr_cg_pel,arraylen_cg_pel);
raxStop(&ri_cg_pel);
/* Consumers */
addReplyBulkCString(c,"consumers");
addReplyArrayLen(c,raxSize(cg->consumers));
raxIterator ri_consumers;
raxStart(&ri_consumers,cg->consumers);
raxSeek(&ri_consumers,"^",NULL,0);
while(raxNext(&ri_consumers)) {
streamConsumer *consumer = ri_consumers.data;
addReplyMapLen(c,5);
/* Consumer name */
addReplyBulkCString(c,"name");
addReplyBulkCBuffer(c,consumer->name,sdslen(consumer->name));
/* Seen-time */
addReplyBulkCString(c,"seen-time");
addReplyLongLong(c,consumer->seen_time);
/* Active-time */
addReplyBulkCString(c,"active-time");
addReplyLongLong(c,consumer->active_time);
/* Consumer PEL count */
addReplyBulkCString(c,"pel-count");
addReplyLongLong(c,raxSize(consumer->pel));
/* Consumer PEL */
addReplyBulkCString(c,"pending");
long long arraylen_cpel = 0;
void *arrayptr_cpel = addReplyDeferredLen(c);
raxIterator ri_cpel;
raxStart(&ri_cpel,consumer->pel);
raxSeek(&ri_cpel,"^",NULL,0);
while(raxNext(&ri_cpel) && (!count || arraylen_cpel < count)) {
streamNACK *nack = ri_cpel.data;
addReplyArrayLen(c,3);
/* Entry ID. */
streamID id;
streamDecodeID(ri_cpel.key,&id);
addReplyStreamID(c,&id);
/* Last delivery. */
addReplyLongLong(c,nack->delivery_time);
/* Number of deliveries. */
addReplyLongLong(c,nack->delivery_count);
arraylen_cpel++;
}
setDeferredArrayLen(c,arrayptr_cpel,arraylen_cpel);
raxStop(&ri_cpel);
}
raxStop(&ri_consumers);
}
raxStop(&ri_cgroups);
}
}
}
/* XINFO CONSUMERS <key> <group>
* XINFO GROUPS <key>
* XINFO STREAM <key> [FULL [COUNT <count>]]
* XINFO HELP. */
void xinfoCommand(client *c) {
stream *s = NULL;
char *opt;
robj *key;
/* HELP is special. Handle it ASAP. */
if (!strcasecmp(c->argv[1]->ptr,"HELP")) {
const char *help[] = {
"CONSUMERS <key> <groupname>",
" Show consumers of <groupname>.",
"GROUPS <key>",
" Show the stream consumer groups.",
"STREAM <key> [FULL [COUNT <count>]",
" Show information about the stream.",
NULL
};
addReplyHelp(c, help);
return;
}
/* With the exception of HELP handled before any other sub commands, all
* the ones are in the form of "<subcommand> <key>". */
opt = c->argv[1]->ptr;
key = c->argv[2];
/* Lookup the key now, this is common for all the subcommands but HELP. */
robj *o = lookupKeyReadOrReply(c,key,shared.nokeyerr);
if (o == NULL || checkType(c,o,OBJ_STREAM)) return;
s = o->ptr;
/* Dispatch the different subcommands. */
if (!strcasecmp(opt,"CONSUMERS") && c->argc == 4) {
/* XINFO CONSUMERS <key> <group>. */
streamCG *cg = streamLookupCG(s,c->argv[3]->ptr);
if (cg == NULL) {
addReplyErrorFormat(c, "-NOGROUP No such consumer group '%s' "
"for key name '%s'",
(char*)c->argv[3]->ptr, (char*)key->ptr);
return;
}
addReplyArrayLen(c,raxSize(cg->consumers));
raxIterator ri;
raxStart(&ri,cg->consumers);
raxSeek(&ri,"^",NULL,0);
mstime_t now = commandTimeSnapshot();
while(raxNext(&ri)) {
streamConsumer *consumer = ri.data;
mstime_t inactive = consumer->active_time != -1 ? now - consumer->active_time : consumer->active_time;
mstime_t idle = now - consumer->seen_time;
if (idle < 0) idle = 0;
addReplyMapLen(c,4);
addReplyBulkCString(c,"name");
addReplyBulkCBuffer(c,consumer->name,sdslen(consumer->name));
addReplyBulkCString(c,"pending");
addReplyLongLong(c,raxSize(consumer->pel));
addReplyBulkCString(c,"idle");
addReplyLongLong(c,idle);
addReplyBulkCString(c,"inactive");
addReplyLongLong(c,inactive);
}
raxStop(&ri);
} else if (!strcasecmp(opt,"GROUPS") && c->argc == 3) {
/* XINFO GROUPS <key>. */
if (s->cgroups == NULL) {
addReplyArrayLen(c,0);
return;
}
addReplyArrayLen(c,raxSize(s->cgroups));
raxIterator ri;
raxStart(&ri,s->cgroups);
raxSeek(&ri,"^",NULL,0);
while(raxNext(&ri)) {
streamCG *cg = ri.data;
addReplyMapLen(c,6);
addReplyBulkCString(c,"name");
addReplyBulkCBuffer(c,ri.key,ri.key_len);
addReplyBulkCString(c,"consumers");
addReplyLongLong(c,raxSize(cg->consumers));
addReplyBulkCString(c,"pending");
addReplyLongLong(c,raxSize(cg->pel));
addReplyBulkCString(c,"last-delivered-id");
addReplyStreamID(c,&cg->last_id);
addReplyBulkCString(c,"entries-read");
if (cg->entries_read != SCG_INVALID_ENTRIES_READ) {
addReplyLongLong(c,cg->entries_read);
} else {
addReplyNull(c);
}
addReplyBulkCString(c,"lag");
streamReplyWithCGLag(c,s,cg);
}
raxStop(&ri);
} else if (!strcasecmp(opt,"STREAM")) {
/* XINFO STREAM <key> [FULL [COUNT <count>]]. */
xinfoReplyWithStreamInfo(c,s);
} else {
addReplySubcommandSyntaxError(c);
}
}
/* Validate the integrity stream listpack entries structure. Both in term of a
* valid listpack, but also that the structure of the entries matches a valid
* stream. return 1 if valid 0 if not valid. */
int streamValidateListpackIntegrity(unsigned char *lp, size_t size, int deep) {
int valid_record;
unsigned char *p, *next;
/* Since we don't want to run validation of all records twice, we'll
* run the listpack validation of just the header and do the rest here. */
if (!lpValidateIntegrity(lp, size, 0, NULL, NULL))
return 0;
/* In non-deep mode we just validated the listpack header (encoded size) */
if (!deep) return 1;
next = p = lpValidateFirst(lp);
if (!lpValidateNext(lp, &next, size)) return 0;
if (!p) return 0;
/* entry count */
int64_t entry_count = lpGetIntegerIfValid(p, &valid_record);
if (!valid_record) return 0;
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
/* deleted */
int64_t deleted_count = lpGetIntegerIfValid(p, &valid_record);
if (!valid_record) return 0;
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
/* num-of-fields */
int64_t master_fields = lpGetIntegerIfValid(p, &valid_record);
if (!valid_record) return 0;
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
/* the field names */
for (int64_t j = 0; j < master_fields; j++) {
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
}
/* the zero master entry terminator. */
int64_t zero = lpGetIntegerIfValid(p, &valid_record);
if (!valid_record || zero != 0) return 0;
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
entry_count += deleted_count;
while (entry_count--) {
if (!p) return 0;
int64_t fields = master_fields, extra_fields = 3;
int64_t flags = lpGetIntegerIfValid(p, &valid_record);
if (!valid_record) return 0;
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
/* entry id */
lpGetIntegerIfValid(p, &valid_record);
if (!valid_record) return 0;
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
lpGetIntegerIfValid(p, &valid_record);
if (!valid_record) return 0;
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
if (!(flags & STREAM_ITEM_FLAG_SAMEFIELDS)) {
/* num-of-fields */
fields = lpGetIntegerIfValid(p, &valid_record);
if (!valid_record) return 0;
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
/* the field names */
for (int64_t j = 0; j < fields; j++) {
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
}
extra_fields += fields + 1;
}
/* the values */
for (int64_t j = 0; j < fields; j++) {
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
}
/* lp-count */
int64_t lp_count = lpGetIntegerIfValid(p, &valid_record);
if (!valid_record) return 0;
if (lp_count != fields + extra_fields) return 0;
p = next; if (!lpValidateNext(lp, &next, size)) return 0;
}
if (next)
return 0;
return 1;
}
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