fts-backend-solr-old.c revision ebcb8cc4fe8862e364f03dcbc05e3db8aac98230
/* Copyright (c) 2006-2015 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "array.h"
#include "str.h"
#include "hash.h"
#include "strescape.h"
#include "unichar.h"
#include "http-url.h"
#include "imap-utf7.h"
#include "mail-storage-private.h"
#include "mailbox-list-private.h"
#include "mail-search.h"
#include "fts-api.h"
#include "solr-connection.h"
#include "fts-solr-plugin.h"
#include <ctype.h>
#define SOLR_CMDBUF_SIZE (1024*64)
#define SOLR_MAX_MULTI_ROWS 100000
struct solr_fts_backend {
struct fts_backend backend;
struct solr_connection *solr_conn;
char *id_username, *id_namespace;
struct mail_namespace *default_ns;
};
struct solr_fts_backend_update_context {
struct fts_backend_update_context ctx;
struct mailbox *cur_box;
char *id_box_name;
struct solr_connection_post *post;
uint32_t prev_uid, uid_validity;
string_t *cmd, *hdr;
bool headers_open;
bool body_open;
bool documents_added;
};
static const char *solr_escape_chars = "+-&|!(){}[]^\"~*?:\\/ ";
static bool is_valid_xml_char(unichar_t chr)
{
/* Valid characters in XML:
#x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] |
[#x10000-#x10FFFF]
This function gets called only for #x80 and higher */
if (chr > 0xd7ff && chr < 0xe000)
return FALSE;
if (chr > 0xfffd && chr < 0x10000)
return FALSE;
return chr < 0x10ffff;
}
static void
xml_encode_data(string_t *dest, const unsigned char *data, unsigned int len)
{
unichar_t chr;
unsigned int i;
for (i = 0; i < len; i++) {
switch (data[i]) {
case '&':
str_append(dest, "&amp;");
break;
case '<':
str_append(dest, "&lt;");
break;
case '>':
str_append(dest, "&gt;");
break;
case '\t':
case '\n':
case '\r':
/* exceptions to the following control char check */
str_append_c(dest, data[i]);
break;
default:
if (data[i] < 32) {
/* SOLR doesn't like control characters.
replace them with spaces. */
str_append_c(dest, ' ');
} else if (data[i] >= 0x80) {
/* make sure the character is valid for XML
so we don't get XML parser errors */
unsigned int char_len =
uni_utf8_get_char_n(data + i, len - i, &chr);
if (char_len > 0 && is_valid_xml_char(chr))
str_append_n(dest, data + i, char_len);
else {
str_append_n(dest, utf8_replacement_char,
UTF8_REPLACEMENT_CHAR_LEN);
}
i += char_len - 1;
} else {
str_append_c(dest, data[i]);
}
break;
}
}
}
static void xml_encode(string_t *dest, const char *str)
{
xml_encode_data(dest, (const unsigned char *)str, strlen(str));
}
static const char *solr_escape_id_str(const char *str)
{
string_t *tmp;
const char *p;
for (p = str; *p != '\0'; p++) {
if (*p == '/' || *p == '!')
break;
}
if (*p == '\0')
return str;
tmp = t_str_new(64);
for (p = str; *p != '\0'; p++) {
switch (*p) {
case '/':
str_append(tmp, "!\\");
break;
case '!':
str_append(tmp, "!!");
break;
default:
str_append_c(tmp, *p);
break;
}
}
return str_c(tmp);
}
static const char *solr_escape(const char *str)
{
string_t *ret;
unsigned int i;
ret = t_str_new(strlen(str) + 16);
for (i = 0; str[i] != '\0'; i++) {
if (strchr(solr_escape_chars, str[i]) != NULL)
str_append_c(ret, '\\');
str_append_c(ret, str[i]);
}
return str_c(ret);
}
static void solr_quote(string_t *dest, const char *str)
{
str_append(dest, solr_escape(str));
}
static void solr_quote_http(string_t *dest, const char *str)
{
http_url_escape_param(dest, solr_escape(str));
}
static void fts_solr_set_default_ns(struct solr_fts_backend *backend)
{
struct mail_namespace *ns = backend->backend.ns;
struct fts_solr_user *fuser = FTS_SOLR_USER_CONTEXT(ns->user);
const struct fts_solr_settings *set = &fuser->set;
const char *str;
if (backend->default_ns != NULL)
return;
if (set->default_ns_prefix != NULL) {
backend->default_ns =
mail_namespace_find_prefix(ns->user->namespaces,
set->default_ns_prefix);
if (backend->default_ns == NULL) {
i_error("fts_solr: default_ns setting points to "
"nonexistent namespace");
}
}
if (backend->default_ns == NULL) {
backend->default_ns =
mail_namespace_find_inbox(ns->user->namespaces);
}
while (backend->default_ns->alias_for != NULL)
backend->default_ns = backend->default_ns->alias_for;
if (ns != backend->default_ns) {
str = solr_escape_id_str(ns->prefix);
backend->id_namespace = i_strdup(str);
}
}
static void fts_box_name_get_root(struct mail_namespace **ns, const char **name)
{
struct mail_namespace *orig_ns = *ns;
while ((*ns)->alias_for != NULL)
*ns = (*ns)->alias_for;
if (**name == '\0' && *ns != orig_ns &&
((*ns)->flags & NAMESPACE_FLAG_INBOX_USER) != 0) {
/* ugly workaround to allow selecting INBOX from a Maildir/
when it's not in the inbox=yes namespace. */
*name = "INBOX";
}
}
static const char *
fts_box_get_root(struct mailbox *box, struct mail_namespace **ns_r)
{
struct mail_namespace *ns = mailbox_get_namespace(box);
const char *name;
if (t_imap_utf8_to_utf7(box->name, &name) < 0)
i_unreached();
fts_box_name_get_root(&ns, &name);
*ns_r = ns;
return name;
}
static struct fts_backend *fts_backend_solr_alloc(void)
{
struct solr_fts_backend *backend;
backend = i_new(struct solr_fts_backend, 1);
backend->backend = fts_backend_solr_old;
return &backend->backend;
}
static int
fts_backend_solr_init(struct fts_backend *_backend, const char **error_r)
{
struct solr_fts_backend *backend = (struct solr_fts_backend *)_backend;
struct fts_solr_user *fuser = FTS_SOLR_USER_CONTEXT(_backend->ns->user);
const char *str;
if (fuser == NULL) {
*error_r = "Invalid fts_solr setting";
return -1;
}
if (solr_connection_init(fuser->set.url, fuser->set.debug,
&backend->solr_conn, error_r) < 0)
return -1;
str = solr_escape_id_str(_backend->ns->user->username);
backend->id_username = i_strdup(str);
return 0;
}
static void fts_backend_solr_deinit(struct fts_backend *_backend)
{
struct solr_fts_backend *backend = (struct solr_fts_backend *)_backend;
solr_connection_deinit(&backend->solr_conn);
i_free(backend->id_namespace);
i_free(backend->id_username);
i_free(backend);
}
static void
solr_add_ns_query(string_t *str, struct solr_fts_backend *backend,
struct mail_namespace *ns, bool neg)
{
while (ns->alias_for != NULL)
ns = ns->alias_for;
if (ns == backend->default_ns || *ns->prefix == '\0') {
if (!neg)
str_append(str, " -ns:[* TO *]");
else
str_append(str, " +ns:[* TO *]");
} else {
if (!neg)
str_append(str, " +ns:");
else
str_append(str, " -ns:");
solr_quote(str, ns->prefix);
}
}
static void
solr_add_ns_query_http(string_t *str, struct solr_fts_backend *backend,
struct mail_namespace *ns)
{
string_t *tmp;
tmp = t_str_new(64);
solr_add_ns_query(tmp, backend, ns, FALSE);
http_url_escape_param(str, str_c(tmp));
}
static int
fts_backend_solr_get_last_uid_fallback(struct solr_fts_backend *backend,
struct mailbox *box,
uint32_t *last_uid_r)
{
struct mail_namespace *ns;
struct mailbox_status status;
struct solr_result **results;
const struct seq_range *uidvals;
const char *box_name;
unsigned int count;
string_t *str;
pool_t pool;
int ret = 0;
str = t_str_new(256);
str_append(str, "fl=uid&rows=1&sort=uid+desc&q=");
box_name = fts_box_get_root(box, &ns);
mailbox_get_open_status(box, STATUS_UIDVALIDITY, &status);
str_printfa(str, "uidv:%u+AND+box:", status.uidvalidity);
solr_quote_http(str, box_name);
solr_add_ns_query_http(str, backend, ns);
str_append(str, "+AND+user:");
solr_quote_http(str, ns->user->username);
pool = pool_alloconly_create("solr last uid lookup", 1024);
if (solr_connection_select(backend->solr_conn, str_c(str),
pool, &results) < 0)
ret = -1;
else if (results[0] == NULL) {
/* no UIDs */
*last_uid_r = 0;
} else {
uidvals = array_get(&results[0]->uids, &count);
i_assert(count > 0);
if (count == 1 && uidvals[0].seq1 == uidvals[0].seq2) {
*last_uid_r = uidvals[0].seq1;
} else {
i_error("fts_solr: Last UID lookup returned multiple rows");
ret = -1;
}
}
pool_unref(&pool);
return ret;
}
static int
fts_backend_solr_get_last_uid(struct fts_backend *_backend,
struct mailbox *box, uint32_t *last_uid_r)
{
struct solr_fts_backend *backend =
(struct solr_fts_backend *)_backend;
struct fts_index_header hdr;
if (fts_index_get_header(box, &hdr)) {
*last_uid_r = hdr.last_indexed_uid;
return 0;
}
/* either nothing has been indexed, or the index was corrupted.
do it the slow way. */
if (fts_backend_solr_get_last_uid_fallback(backend, box, last_uid_r) < 0)
return -1;
fts_index_set_last_uid(box, *last_uid_r);
return 0;
}
static struct fts_backend_update_context *
fts_backend_solr_update_init(struct fts_backend *_backend)
{
struct solr_fts_backend *backend =
(struct solr_fts_backend *)_backend;
struct solr_fts_backend_update_context *ctx;
ctx = i_new(struct solr_fts_backend_update_context, 1);
ctx->ctx.backend = _backend;
ctx->cmd = str_new(default_pool, SOLR_CMDBUF_SIZE);
ctx->hdr = str_new(default_pool, 4096);
fts_solr_set_default_ns(backend);
return &ctx->ctx;
}
static void xml_encode_id(struct solr_fts_backend_update_context *ctx,
string_t *str, uint32_t uid)
{
struct solr_fts_backend *backend =
(struct solr_fts_backend *)ctx->ctx.backend;
if (uid != 0)
str_printfa(str, "%u/", uid);
else
str_append(str, "L/");
if (backend->id_namespace != NULL) {
xml_encode(str, backend->id_namespace);
str_append_c(str, '/');
}
str_printfa(str, "%u/", ctx->uid_validity);
xml_encode(str, backend->id_username);
str_append_c(str, '/');
xml_encode(str, ctx->id_box_name);
}
static void
fts_backend_solr_add_doc_prefix(struct solr_fts_backend_update_context *ctx,
uint32_t uid)
{
struct solr_fts_backend *backend =
(struct solr_fts_backend *)ctx->ctx.backend;
struct mailbox *box = ctx->cur_box;
struct mail_namespace *ns;
const char *box_name;
ctx->documents_added = TRUE;
str_printfa(ctx->cmd, "<doc>"
"<field name=\"uid\">%u</field>"
"<field name=\"uidv\">%u</field>",
uid, ctx->uid_validity);
box_name = fts_box_get_root(box, &ns);
if (ns != backend->default_ns) {
str_append(ctx->cmd, "<field name=\"ns\">");
xml_encode(ctx->cmd, ns->prefix);
str_append(ctx->cmd, "</field>");
}
str_append(ctx->cmd, "<field name=\"box\">");
xml_encode(ctx->cmd, box_name);
str_append(ctx->cmd, "</field><field name=\"user\">");
xml_encode(ctx->cmd, ns->user->username);
str_append(ctx->cmd, "</field>");
}
static int
fts_backed_solr_build_commit(struct solr_fts_backend_update_context *ctx)
{
if (ctx->post == NULL)
return 0;
str_append(ctx->cmd, "</doc></add>");
solr_connection_post_more(ctx->post, str_data(ctx->cmd),
str_len(ctx->cmd));
return solr_connection_post_end(&ctx->post);
}
static int
fts_backend_solr_update_deinit(struct fts_backend_update_context *_ctx)
{
struct solr_fts_backend_update_context *ctx =
(struct solr_fts_backend_update_context *)_ctx;
struct solr_fts_backend *backend =
(struct solr_fts_backend *)_ctx->backend;
const char *str;
int ret;
ret = fts_backed_solr_build_commit(ctx);
/* commit and wait until the documents we just indexed are
visible to the following search */
str = t_strdup_printf("<commit waitFlush=\"false\" "
"waitSearcher=\"%s\"/>",
ctx->documents_added ? "true" : "false");
if (solr_connection_post(backend->solr_conn, str) < 0)
ret = -1;
str_free(&ctx->cmd);
str_free(&ctx->hdr);
i_free(ctx->id_box_name);
i_free(ctx);
return ret;
}
static void
fts_backend_solr_update_set_mailbox(struct fts_backend_update_context *_ctx,
struct mailbox *box)
{
struct solr_fts_backend_update_context *ctx =
(struct solr_fts_backend_update_context *)_ctx;
struct mailbox_status status;
struct mail_namespace *ns;
if (ctx->prev_uid != 0) {
fts_index_set_last_uid(ctx->cur_box, ctx->prev_uid);
ctx->prev_uid = 0;
}
ctx->cur_box = box;
ctx->uid_validity = 0;
i_free_and_null(ctx->id_box_name);
if (box != NULL) {
ctx->id_box_name = i_strdup(fts_box_get_root(box, &ns));
mailbox_get_open_status(box, STATUS_UIDVALIDITY, &status);
ctx->uid_validity = status.uidvalidity;
}
}
static void
fts_backend_solr_update_expunge(struct fts_backend_update_context *_ctx,
uint32_t uid)
{
struct solr_fts_backend_update_context *ctx =
(struct solr_fts_backend_update_context *)_ctx;
struct solr_fts_backend *backend =
(struct solr_fts_backend *)_ctx->backend;
T_BEGIN {
string_t *cmd;
cmd = t_str_new(256);
str_append(cmd, "<delete><id>");
xml_encode_id(ctx, cmd, uid);
str_append(cmd, "</id></delete>");
(void)solr_connection_post(backend->solr_conn, str_c(cmd));
} T_END;
}
static void
fts_backend_solr_uid_changed(struct solr_fts_backend_update_context *ctx,
uint32_t uid)
{
struct solr_fts_backend *backend =
(struct solr_fts_backend *)ctx->ctx.backend;
if (ctx->post == NULL) {
i_assert(ctx->prev_uid == 0);
ctx->post = solr_connection_post_begin(backend->solr_conn);
str_append(ctx->cmd, "<add>");
} else {
ctx->headers_open = FALSE;
if (ctx->body_open) {
ctx->body_open = FALSE;
str_append(ctx->cmd, "</field>");
}
str_append(ctx->cmd, "<field name=\"hdr\">");
str_append_str(ctx->cmd, ctx->hdr);
str_append(ctx->cmd, "</field>");
str_truncate(ctx->hdr, 0);
str_append(ctx->cmd, "</doc>");
}
ctx->prev_uid = uid;
fts_backend_solr_add_doc_prefix(ctx, uid);
str_printfa(ctx->cmd, "<field name=\"id\">");
xml_encode_id(ctx, ctx->cmd, uid);
str_append(ctx->cmd, "</field>");
}
static bool
fts_backend_solr_update_set_build_key(struct fts_backend_update_context *_ctx,
const struct fts_backend_build_key *key)
{
struct solr_fts_backend_update_context *ctx =
(struct solr_fts_backend_update_context *)_ctx;
if (key->uid != ctx->prev_uid)
fts_backend_solr_uid_changed(ctx, key->uid);
switch (key->type) {
case FTS_BACKEND_BUILD_KEY_HDR:
case FTS_BACKEND_BUILD_KEY_MIME_HDR:
xml_encode(ctx->hdr, key->hdr_name);
str_append(ctx->hdr, ": ");
ctx->headers_open = TRUE;
break;
case FTS_BACKEND_BUILD_KEY_BODY_PART:
ctx->headers_open = FALSE;
if (!ctx->body_open) {
ctx->body_open = TRUE;
str_append(ctx->cmd, "<field name=\"body\">");
}
break;
case FTS_BACKEND_BUILD_KEY_BODY_PART_BINARY:
i_unreached();
}
return TRUE;
}
static void
fts_backend_solr_update_unset_build_key(struct fts_backend_update_context *_ctx)
{
struct solr_fts_backend_update_context *ctx =
(struct solr_fts_backend_update_context *)_ctx;
if (ctx->headers_open)
str_append_c(ctx->hdr, '\n');
else {
i_assert(ctx->body_open);
str_append_c(ctx->cmd, '\n');
}
}
static int
fts_backend_solr_update_build_more(struct fts_backend_update_context *_ctx,
const unsigned char *data, size_t size)
{
struct solr_fts_backend_update_context *ctx =
(struct solr_fts_backend_update_context *)_ctx;
xml_encode_data(ctx->cmd, data, size);
if (str_len(ctx->cmd) > SOLR_CMDBUF_SIZE-128) {
solr_connection_post_more(ctx->post, str_data(ctx->cmd),
str_len(ctx->cmd));
str_truncate(ctx->cmd, 0);
}
return 0;
}
static int fts_backend_solr_refresh(struct fts_backend *backend ATTR_UNUSED)
{
return 0;
}
static int fts_backend_solr_optimize(struct fts_backend *backend ATTR_UNUSED)
{
return 0;
}
static bool
solr_add_definite_query(string_t *str, struct mail_search_arg *arg)
{
switch (arg->type) {
case SEARCH_TEXT: {
if (arg->match_not)
str_append_c(str, '-');
str_append(str, "(hdr:");
solr_quote_http(str, arg->value.str);
str_append(str, "+OR+body:");
solr_quote_http(str, arg->value.str);
str_append(str, ")");
break;
}
case SEARCH_BODY:
if (arg->match_not)
str_append_c(str, '-');
str_append(str, "body:");
solr_quote_http(str, arg->value.str);
break;
default:
return FALSE;
}
return TRUE;
}
static bool
solr_add_definite_query_args(string_t *str, struct mail_search_arg *arg,
bool and_args)
{
unsigned int last_len;
last_len = str_len(str);
for (; arg != NULL; arg = arg->next) {
if (solr_add_definite_query(str, arg)) {
arg->match_always = TRUE;
last_len = str_len(str);
if (and_args)
str_append(str, "+AND+");
else
str_append(str, "+OR+");
}
}
if (str_len(str) == last_len)
return FALSE;
str_truncate(str, last_len);
return TRUE;
}
static int
fts_backend_solr_lookup(struct fts_backend *_backend, struct mailbox *box,
struct mail_search_arg *args,
enum fts_lookup_flags flags,
struct fts_result *result)
{
struct solr_fts_backend *backend =
(struct solr_fts_backend *)_backend;
bool and_args = (flags & FTS_LOOKUP_FLAG_AND_ARGS) != 0;
struct mail_namespace *ns;
struct mailbox_status status;
string_t *str;
const char *box_name;
pool_t pool;
struct solr_result **results;
int ret;
fts_solr_set_default_ns(backend);
mailbox_get_open_status(box, STATUS_UIDVALIDITY | STATUS_UIDNEXT,
&status);
str = t_str_new(256);
str_printfa(str, "fl=uid,score&rows=%u&sort=uid+asc&q=",
status.uidnext);
if (!solr_add_definite_query_args(str, args, and_args)) {
/* can't search this query */
return 0;
}
/* use a separate filter query for selecting the mailbox. it shouldn't
affect the score and there could be some caching benefits too. */
str_append(str, "&fq=%2Buser:");
solr_quote_http(str, box->storage->user->username);
box_name = fts_box_get_root(box, &ns);
str_printfa(str, "+%%2Buidv:%u+%%2Bbox:", status.uidvalidity);
solr_quote_http(str, box_name);
solr_add_ns_query_http(str, backend, ns);
pool = pool_alloconly_create("fts solr search", 1024);
ret = solr_connection_select(backend->solr_conn, str_c(str),
pool, &results);
if (ret == 0 && results[0] != NULL) {
if ((flags & FTS_LOOKUP_FLAG_NO_AUTO_FUZZY) == 0)
array_append_array(&result->definite_uids, &results[0]->uids);
else
array_append_array(&result->maybe_uids, &results[0]->uids);
array_append_array(&result->scores, &results[0]->scores);
}
result->scores_sorted = TRUE;
pool_unref(&pool);
return ret;
}
static char *
mailbox_get_id(struct solr_fts_backend *backend, struct mail_namespace *ns,
const char *mailbox, uint32_t uidvalidity)
{
string_t *str = t_str_new(64);
str_printfa(str, "%u\001", uidvalidity);
str_append(str, mailbox);
if (ns != backend->default_ns)
str_printfa(str, "\001%s", ns->prefix);
return str_c_modifiable(str);
}
static int
solr_search_multi(struct solr_fts_backend *backend, string_t *str,
struct mailbox *const boxes[],
enum fts_lookup_flags flags,
struct fts_multi_result *result)
{
struct solr_result **solr_results;
struct fts_result *fts_result;
ARRAY(struct fts_result) fts_results;
struct mail_namespace *ns;
struct mailbox_status status;
HASH_TABLE(char *, struct mailbox *) mailboxes;
struct mailbox *box;
const char *box_name;
char *box_id;
unsigned int i, len;
/* use a separate filter query for selecting the mailbox. it shouldn't
affect the score and there could be some caching benefits too. */
str_append(str, "&fq=%2Buser:");
if (backend->backend.ns->owner != NULL)
solr_quote_http(str, backend->backend.ns->owner->username);
else
str_append(str, "%22%22");
hash_table_create(&mailboxes, default_pool, 0, str_hash, strcmp);
str_append(str, "%2B(");
len = str_len(str);
for (i = 0; boxes[i] != NULL; i++) {
if (str_len(str) != len)
str_append(str, "+OR+");
box_name = fts_box_get_root(boxes[i], &ns);
mailbox_get_open_status(boxes[i], STATUS_UIDVALIDITY, &status);
str_printfa(str, "%%2B(%%2Buidv:%u+%%2Bbox:", status.uidvalidity);
solr_quote_http(str, box_name);
solr_add_ns_query_http(str, backend, ns);
str_append_c(str, ')');
box_id = mailbox_get_id(backend, ns, box_name, status.uidvalidity);
hash_table_insert(mailboxes, box_id, boxes[i]);
}
str_append_c(str, ')');
if (solr_connection_select(backend->solr_conn, str_c(str),
result->pool, &solr_results) < 0) {
hash_table_destroy(&mailboxes);
return -1;
}
p_array_init(&fts_results, result->pool, 32);
for (i = 0; solr_results[i] != NULL; i++) {
box = hash_table_lookup(mailboxes, solr_results[i]->box_id);
if (box == NULL) {
i_warning("fts_solr: Lookup returned unexpected mailbox "
"with id=%s", solr_results[i]->box_id);
continue;
}
fts_result = array_append_space(&fts_results);
fts_result->box = box;
if ((flags & FTS_LOOKUP_FLAG_NO_AUTO_FUZZY) == 0)
fts_result->definite_uids = solr_results[i]->uids;
else
fts_result->maybe_uids = solr_results[i]->uids;
fts_result->scores = solr_results[i]->scores;
fts_result->scores_sorted = TRUE;
}
array_append_zero(&fts_results);
result->box_results = array_idx_modifiable(&fts_results, 0);
hash_table_destroy(&mailboxes);
return 0;
}
static int
fts_backend_solr_lookup_multi(struct fts_backend *_backend,
struct mailbox *const boxes[],
struct mail_search_arg *args,
enum fts_lookup_flags flags,
struct fts_multi_result *result)
{
bool and_args = (flags & FTS_LOOKUP_FLAG_AND_ARGS) != 0;
struct solr_fts_backend *backend =
(struct solr_fts_backend *)_backend;
string_t *str;
fts_solr_set_default_ns(backend);
str = t_str_new(256);
str_printfa(str, "fl=ns,box,uidv,uid,score&rows=%u&sort=box+asc,uid+asc&q=",
SOLR_MAX_MULTI_ROWS);
if (solr_add_definite_query_args(str, args, and_args)) {
if (solr_search_multi(backend, str, boxes, flags, result) < 0)
return -1;
}
/* FIXME: maybe_uids could be handled also with some more work.. */
return 0;
}
struct fts_backend fts_backend_solr_old = {
.name = "solr_old",
.flags = 0,
{
fts_backend_solr_alloc,
fts_backend_solr_init,
fts_backend_solr_deinit,
fts_backend_solr_get_last_uid,
fts_backend_solr_update_init,
fts_backend_solr_update_deinit,
fts_backend_solr_update_set_mailbox,
fts_backend_solr_update_expunge,
fts_backend_solr_update_set_build_key,
fts_backend_solr_update_unset_build_key,
fts_backend_solr_update_build_more,
fts_backend_solr_refresh,
NULL,
fts_backend_solr_optimize,
fts_backend_default_can_lookup,
fts_backend_solr_lookup,
fts_backend_solr_lookup_multi,
NULL
}
};