wparser.c

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/*-------------------------------------------------------------------------
 *
 * wparser.c
 *      Standard interface to word parser
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 *
 *
 * IDENTIFICATION
 *    src/backend/tsearch/wparser.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "funcapi.h"
#include "catalog/namespace.h"
#include "catalog/pg_type.h"
#include "commands/defrem.h"
#include "tsearch/ts_cache.h"
#include "tsearch/ts_utils.h"
#include "utils/builtins.h"


/******sql-level interface******/

typedef struct
{
    int         cur;
    LexDescr   *list;
} TSTokenTypeStorage;

static void
tt_setup_firstcall(FuncCallContext *funcctx, Oid prsid)
{
    TupleDesc   tupdesc;
    MemoryContext oldcontext;
    TSTokenTypeStorage *st;
    TSParserCacheEntry *prs = lookup_ts_parser_cache(prsid);

    if (!OidIsValid(prs->lextypeOid))
        elog(ERROR, "method lextype isn't defined for text search parser %u",
             prsid);

    oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

    st = (TSTokenTypeStorage *) palloc(sizeof(TSTokenTypeStorage));
    st->cur = 0;
    /* lextype takes one dummy argument */
    st->list = (LexDescr *) DatumGetPointer(OidFunctionCall1(prs->lextypeOid,
                                                             (Datum) 0));
    funcctx->user_fctx = (void *) st;

    tupdesc = CreateTemplateTupleDesc(3, false);
    TupleDescInitEntry(tupdesc, (AttrNumber) 1, "tokid",
                       INT4OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 2, "alias",
                       TEXTOID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 3, "description",
                       TEXTOID, -1, 0);

    funcctx->attinmeta = TupleDescGetAttInMetadata(tupdesc);
    MemoryContextSwitchTo(oldcontext);
}

static Datum
tt_process_call(FuncCallContext *funcctx)
{
    TSTokenTypeStorage *st;

    st = (TSTokenTypeStorage *) funcctx->user_fctx;
    if (st->list && st->list[st->cur].lexid)
    {
        Datum       result;
        char       *values[3];
        char        txtid[16];
        HeapTuple   tuple;

        sprintf(txtid, "%d", st->list[st->cur].lexid);
        values[0] = txtid;
        values[1] = st->list[st->cur].alias;
        values[2] = st->list[st->cur].descr;

        tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
        result = HeapTupleGetDatum(tuple);

        pfree(values[1]);
        pfree(values[2]);
        st->cur++;
        return result;
    }
    if (st->list)
        pfree(st->list);
    pfree(st);
    return (Datum) 0;
}

Datum
ts_token_type_byid(PG_FUNCTION_ARGS)
{
    FuncCallContext *funcctx;
    Datum       result;

    if (SRF_IS_FIRSTCALL())
    {
        funcctx = SRF_FIRSTCALL_INIT();
        tt_setup_firstcall(funcctx, PG_GETARG_OID(0));
    }

    funcctx = SRF_PERCALL_SETUP();

    if ((result = tt_process_call(funcctx)) != (Datum) 0)
        SRF_RETURN_NEXT(funcctx, result);
    SRF_RETURN_DONE(funcctx);
}

Datum
ts_token_type_byname(PG_FUNCTION_ARGS)
{
    FuncCallContext *funcctx;
    Datum       result;

    if (SRF_IS_FIRSTCALL())
    {
        text       *prsname = PG_GETARG_TEXT_P(0);
        Oid         prsId;

        funcctx = SRF_FIRSTCALL_INIT();
        prsId = get_ts_parser_oid(textToQualifiedNameList(prsname), false);
        tt_setup_firstcall(funcctx, prsId);
    }

    funcctx = SRF_PERCALL_SETUP();

    if ((result = tt_process_call(funcctx)) != (Datum) 0)
        SRF_RETURN_NEXT(funcctx, result);
    SRF_RETURN_DONE(funcctx);
}

typedef struct
{
    int         type;
    char       *lexeme;
} LexemeEntry;

typedef struct
{
    int         cur;
    int         len;
    LexemeEntry *list;
} PrsStorage;


static void
prs_setup_firstcall(FuncCallContext *funcctx, Oid prsid, text *txt)
{
    TupleDesc   tupdesc;
    MemoryContext oldcontext;
    PrsStorage *st;
    TSParserCacheEntry *prs = lookup_ts_parser_cache(prsid);
    char       *lex = NULL;
    int         llen = 0,
                type = 0;
    void       *prsdata;

    oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

    st = (PrsStorage *) palloc(sizeof(PrsStorage));
    st->cur = 0;
    st->len = 16;
    st->list = (LexemeEntry *) palloc(sizeof(LexemeEntry) * st->len);

    prsdata = (void *) DatumGetPointer(FunctionCall2(&prs->prsstart,
                                               PointerGetDatum(VARDATA(txt)),
                                    Int32GetDatum(VARSIZE(txt) - VARHDRSZ)));

    while ((type = DatumGetInt32(FunctionCall3(&prs->prstoken,
                                               PointerGetDatum(prsdata),
                                               PointerGetDatum(&lex),
                                               PointerGetDatum(&llen)))) != 0)
    {
        if (st->cur >= st->len)
        {
            st->len = 2 * st->len;
            st->list = (LexemeEntry *) repalloc(st->list, sizeof(LexemeEntry) * st->len);
        }
        st->list[st->cur].lexeme = palloc(llen + 1);
        memcpy(st->list[st->cur].lexeme, lex, llen);
        st->list[st->cur].lexeme[llen] = '\0';
        st->list[st->cur].type = type;
        st->cur++;
    }

    FunctionCall1(&prs->prsend, PointerGetDatum(prsdata));

    st->len = st->cur;
    st->cur = 0;

    funcctx->user_fctx = (void *) st;
    tupdesc = CreateTemplateTupleDesc(2, false);
    TupleDescInitEntry(tupdesc, (AttrNumber) 1, "tokid",
                       INT4OID, -1, 0);
    TupleDescInitEntry(tupdesc, (AttrNumber) 2, "token",
                       TEXTOID, -1, 0);

    funcctx->attinmeta = TupleDescGetAttInMetadata(tupdesc);
    MemoryContextSwitchTo(oldcontext);
}

static Datum
prs_process_call(FuncCallContext *funcctx)
{
    PrsStorage *st;

    st = (PrsStorage *) funcctx->user_fctx;
    if (st->cur < st->len)
    {
        Datum       result;
        char       *values[2];
        char        tid[16];
        HeapTuple   tuple;

        values[0] = tid;
        sprintf(tid, "%d", st->list[st->cur].type);
        values[1] = st->list[st->cur].lexeme;
        tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
        result = HeapTupleGetDatum(tuple);

        pfree(values[1]);
        st->cur++;
        return result;
    }
    else
    {
        if (st->list)
            pfree(st->list);
        pfree(st);
    }
    return (Datum) 0;
}

Datum
ts_parse_byid(PG_FUNCTION_ARGS)
{
    FuncCallContext *funcctx;
    Datum       result;

    if (SRF_IS_FIRSTCALL())
    {
        text       *txt = PG_GETARG_TEXT_P(1);

        funcctx = SRF_FIRSTCALL_INIT();
        prs_setup_firstcall(funcctx, PG_GETARG_OID(0), txt);
        PG_FREE_IF_COPY(txt, 1);
    }

    funcctx = SRF_PERCALL_SETUP();

    if ((result = prs_process_call(funcctx)) != (Datum) 0)
        SRF_RETURN_NEXT(funcctx, result);
    SRF_RETURN_DONE(funcctx);
}

Datum
ts_parse_byname(PG_FUNCTION_ARGS)
{
    FuncCallContext *funcctx;
    Datum       result;

    if (SRF_IS_FIRSTCALL())
    {
        text       *prsname = PG_GETARG_TEXT_P(0);
        text       *txt = PG_GETARG_TEXT_P(1);
        Oid         prsId;

        funcctx = SRF_FIRSTCALL_INIT();
        prsId = get_ts_parser_oid(textToQualifiedNameList(prsname), false);
        prs_setup_firstcall(funcctx, prsId, txt);
    }

    funcctx = SRF_PERCALL_SETUP();

    if ((result = prs_process_call(funcctx)) != (Datum) 0)
        SRF_RETURN_NEXT(funcctx, result);
    SRF_RETURN_DONE(funcctx);
}

Datum
ts_headline_byid_opt(PG_FUNCTION_ARGS)
{
    text       *in = PG_GETARG_TEXT_P(1);
    TSQuery     query = PG_GETARG_TSQUERY(2);
    text       *opt = (PG_NARGS() > 3 && PG_GETARG_POINTER(3)) ? PG_GETARG_TEXT_P(3) : NULL;
    HeadlineParsedText prs;
    List       *prsoptions;
    text       *out;
    TSConfigCacheEntry *cfg;
    TSParserCacheEntry *prsobj;

    cfg = lookup_ts_config_cache(PG_GETARG_OID(0));
    prsobj = lookup_ts_parser_cache(cfg->prsId);

    if (!OidIsValid(prsobj->headlineOid))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
           errmsg("text search parser does not support headline creation")));

    memset(&prs, 0, sizeof(HeadlineParsedText));
    prs.lenwords = 32;
    prs.words = (HeadlineWordEntry *) palloc(sizeof(HeadlineWordEntry) * prs.lenwords);

    hlparsetext(cfg->cfgId, &prs, query, VARDATA(in), VARSIZE(in) - VARHDRSZ);

    if (opt)
        prsoptions = deserialize_deflist(PointerGetDatum(opt));
    else
        prsoptions = NIL;

    FunctionCall3(&(prsobj->prsheadline),
                  PointerGetDatum(&prs),
                  PointerGetDatum(prsoptions),
                  PointerGetDatum(query));

    out = generateHeadline(&prs);

    PG_FREE_IF_COPY(in, 1);
    PG_FREE_IF_COPY(query, 2);
    if (opt)
        PG_FREE_IF_COPY(opt, 3);
    pfree(prs.words);
    pfree(prs.startsel);
    pfree(prs.stopsel);

    PG_RETURN_POINTER(out);
}

Datum
ts_headline_byid(PG_FUNCTION_ARGS)
{
    PG_RETURN_DATUM(DirectFunctionCall3(ts_headline_byid_opt,
                                        PG_GETARG_DATUM(0),
                                        PG_GETARG_DATUM(1),
                                        PG_GETARG_DATUM(2)));
}

Datum
ts_headline(PG_FUNCTION_ARGS)
{
    PG_RETURN_DATUM(DirectFunctionCall3(ts_headline_byid_opt,
                                  ObjectIdGetDatum(getTSCurrentConfig(true)),
                                        PG_GETARG_DATUM(0),
                                        PG_GETARG_DATUM(1)));
}

Datum
ts_headline_opt(PG_FUNCTION_ARGS)
{
    PG_RETURN_DATUM(DirectFunctionCall4(ts_headline_byid_opt,
                                  ObjectIdGetDatum(getTSCurrentConfig(true)),
                                        PG_GETARG_DATUM(0),
                                        PG_GETARG_DATUM(1),
                                        PG_GETARG_DATUM(2)));
}