lws-fts.h

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/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

 
struct lws_fts;
struct lws_fts_file;
 
/*
 * Queries produce their results in an lwsac, using these public API types.
 * The first thing in the lwsac is always a struct lws_fts_result (see below)
 * containing heads for linked-lists of the other result types.
 */
 
/* one filepath's results */
 
/*
 * Immediately after the struct comes the match table, then the filepath
 * string (of filepath_length, NUL-terminated); .matches_length is the number
 * of bytes in the match table, so the filepath is always at
 * ((char *)&fp[1]) + fp->matches_length.
 *
 * The match table holds exactly .matches fixed-size records, in this order,
 * with no padding and no omissions:
 *
 *  - nothing at all, if LWSFTS_F_QUERY_FILE_LINES was not given
 *
 *  - uint32_t line number, uint32_t byte offset of that line in the original
 *    file, if LWSFTS_F_QUERY_FILE_LINES was given
 *
 *  - the two uint32_t above, then a const char * to a NUL-terminated quote of
 *    the line (also in the results lwsac), if LWSFTS_F_QUERY_QUOTE_LINE was
 *    also given
 *
 * The stride is fixed: if the library could not resolve a particular match
 * (eg, the original file has changed since it was indexed), that record is
 * present but zero, ie, the offset is 0 and the quote pointer is NULL.
 * Consumers must be ready for a NULL quote pointer, but may rely on the
 * record count and stride.
 */
 
struct lws_fts_result_filepath {
        struct lws_fts_result_filepath *next;
        int matches;    /* logical number of matches */
        int matches_length;     /* bytes in length table (may be zero) */
        int lines_in_file;
        int filepath_length;
        char truncated; /* there were more matches, capped by max_lines */
 
        /* - uint32_t line table follows (first for alignment) */
        /* - filepath (of filepath_length) follows */
};
 
/* autocomplete result */
 
struct lws_fts_result_autocomplete {
        struct lws_fts_result_autocomplete *next;
        int instances;
        int agg_instances;
        int ac_length;
        char elided; /* children skipped in interest of antecedent children */
        char has_children;
 
        /* - autocomplete suggestion (of length ac_length) follows */
};
 
/*
 * The results lwsac always starts with this.  If no results and / or no
 * autocomplete the members may be NULL.  This implies the symbol nor any
 * suffix on it exists in the trie file.
 */
struct lws_fts_result {
        struct lws_fts_result_filepath *filepath_head;
        struct lws_fts_result_autocomplete *autocomplete_head;
        int duration_ms;
        int effective_flags; /* the search flags that were used */
        char truncated; /* there were more filepaths, capped by max_files */
};
 
/*
 * index creation functions
 */

LWS_VISIBLE LWS_EXTERN struct lws_fts *
lws_fts_create(int fd);

LWS_VISIBLE LWS_EXTERN void
lws_fts_destroy(struct lws_fts **trie);

LWS_VISIBLE LWS_EXTERN int
lws_fts_file_index(struct lws_fts *t, const char *filepath, int filepath_len,
                   int priority);

LWS_VISIBLE LWS_EXTERN int
lws_fts_fill(struct lws_fts *t, uint32_t file_index, const char *buf,
             size_t len);

LWS_VISIBLE LWS_EXTERN int
lws_fts_serialize(struct lws_fts *t);
 
/*
 * index search functions
 */

LWS_VISIBLE LWS_EXTERN struct lws_fts_file *
lws_fts_open(const char *filepath);
 
#define LWSFTS_F_QUERY_AUTOCOMPLETE     (1 << 0)
#define LWSFTS_F_QUERY_FILES            (1 << 1)
#define LWSFTS_F_QUERY_FILE_LINES       (1 << 2)
#define LWSFTS_F_QUERY_QUOTE_LINE       (1 << 3)
 
struct lws_fts_search_params {
        /* the actual search term */
        const char *needle;
         /* if non-NULL, FILE results for this filepath only */
        const char *only_filepath;
        /* will be set to the results lwsac */
        struct lwsac *results_head;
        /* combination of LWSFTS_F_QUERY_* flags */
        int flags;
        /* maximum number of autocomplete suggestions to return */
        int max_autocomplete;
        /*
         * Maximum number of filepaths to return, 0 = no limit.  If the walk
         * stopped here, result.truncated is set.  Any caller acting on an
         * untrusted needle should set this: a one-character needle otherwise
         * walks the whole indexed corpus into the results lwsac.
         */
        int max_files;
        /*
         * Maximum number of line number results to return per filepath, 0 =
         * no limit (there is still an internal ceiling).  If a filepath's
         * results stopped here, that filepath result's .truncated is set.
         */
        int max_lines;
};

LWS_VISIBLE LWS_EXTERN struct lws_fts_result *
lws_fts_search(struct lws_fts_file *jtf, struct lws_fts_search_params *ftsp);

LWS_VISIBLE LWS_EXTERN void
lws_fts_close(struct lws_fts_file *jtf);