tsearchcmds.c

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/*-------------------------------------------------------------------------
 *
 * tsearchcmds.c
 *
 *    Routines for tsearch manipulation commands
 *
 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/commands/tsearchcmds.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <ctype.h>

#include "access/genam.h"
#include "access/htup_details.h"
#include "access/table.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_ts_config.h"
#include "catalog/pg_ts_config_map.h"
#include "catalog/pg_ts_dict.h"
#include "catalog/pg_ts_parser.h"
#include "catalog/pg_ts_template.h"
#include "catalog/pg_type.h"
#include "commands/alter.h"
#include "commands/defrem.h"
#include "commands/event_trigger.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "parser/parse_func.h"
#include "tsearch/ts_cache.h"
#include "tsearch/ts_utils.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"


static void MakeConfigurationMapping(AlterTSConfigurationStmt *stmt,
                                     HeapTuple tup, Relation relMap);
static void DropConfigurationMapping(AlterTSConfigurationStmt *stmt,
                                     HeapTuple tup, Relation relMap);


/* --------------------- TS Parser commands ------------------------ */

/*
 * lookup a parser support function and return its OID (as a Datum)
 *
 * attnum is the pg_ts_parser column the function will go into
 */
static Datum
get_ts_parser_func(DefElem *defel, int attnum)
{
    List       *funcName = defGetQualifiedName(defel);
    Oid         typeId[3];
    Oid         retTypeId;
    int         nargs;
    Oid         procOid;

    retTypeId = INTERNALOID;    /* correct for most */
    typeId[0] = INTERNALOID;
    switch (attnum)
    {
        case Anum_pg_ts_parser_prsstart:
            nargs = 2;
            typeId[1] = INT4OID;
            break;
        case Anum_pg_ts_parser_prstoken:
            nargs = 3;
            typeId[1] = INTERNALOID;
            typeId[2] = INTERNALOID;
            break;
        case Anum_pg_ts_parser_prsend:
            nargs = 1;
            retTypeId = VOIDOID;
            break;
        case Anum_pg_ts_parser_prsheadline:
            nargs = 3;
            typeId[1] = INTERNALOID;
            typeId[2] = TSQUERYOID;
            break;
        case Anum_pg_ts_parser_prslextype:
            nargs = 1;

            /*
             * Note: because the lextype method returns type internal, it must
             * have an internal-type argument for security reasons.  The
             * argument is not actually used, but is just passed as a zero.
             */
            break;
        default:
            /* should not be here */
            elog(ERROR, "unrecognized attribute for text search parser: %d",
                 attnum);
            nargs = 0;          /* keep compiler quiet */
    }

    procOid = LookupFuncName(funcName, nargs, typeId, false);
    if (get_func_rettype(procOid) != retTypeId)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("function %s should return type %s",
                        func_signature_string(funcName, nargs, NIL, typeId),
                        format_type_be(retTypeId))));

    return ObjectIdGetDatum(procOid);
}

/*
 * make pg_depend entries for a new pg_ts_parser entry
 *
 * Return value is the address of said new entry.
 */
static ObjectAddress
makeParserDependencies(HeapTuple tuple)
{
    Form_pg_ts_parser prs = (Form_pg_ts_parser) GETSTRUCT(tuple);
    ObjectAddress myself,
                referenced;

    myself.classId = TSParserRelationId;
    myself.objectId = prs->oid;
    myself.objectSubId = 0;

    /* dependency on namespace */
    referenced.classId = NamespaceRelationId;
    referenced.objectId = prs->prsnamespace;
    referenced.objectSubId = 0;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

    /* dependency on extension */
    recordDependencyOnCurrentExtension(&myself, false);

    /* dependencies on functions */
    referenced.classId = ProcedureRelationId;
    referenced.objectSubId = 0;

    referenced.objectId = prs->prsstart;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

    referenced.objectId = prs->prstoken;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

    referenced.objectId = prs->prsend;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

    referenced.objectId = prs->prslextype;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

    if (OidIsValid(prs->prsheadline))
    {
        referenced.objectId = prs->prsheadline;
        recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
    }

    return myself;
}

/*
 * CREATE TEXT SEARCH PARSER
 */
ObjectAddress
DefineTSParser(List *names, List *parameters)
{
    char       *prsname;
    ListCell   *pl;
    Relation    prsRel;
    HeapTuple   tup;
    Datum       values[Natts_pg_ts_parser];
    bool        nulls[Natts_pg_ts_parser];
    NameData    pname;
    Oid         prsOid;
    Oid         namespaceoid;
    ObjectAddress address;

    if (!superuser())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be superuser to create text search parsers")));

    prsRel = table_open(TSParserRelationId, RowExclusiveLock);

    /* Convert list of names to a name and namespace */
    namespaceoid = QualifiedNameGetCreationNamespace(names, &prsname);

    /* initialize tuple fields with name/namespace */
    memset(values, 0, sizeof(values));
    memset(nulls, false, sizeof(nulls));

    prsOid = GetNewOidWithIndex(prsRel, TSParserOidIndexId,
                                Anum_pg_ts_parser_oid);
    values[Anum_pg_ts_parser_oid - 1] = ObjectIdGetDatum(prsOid);
    namestrcpy(&pname, prsname);
    values[Anum_pg_ts_parser_prsname - 1] = NameGetDatum(&pname);
    values[Anum_pg_ts_parser_prsnamespace - 1] = ObjectIdGetDatum(namespaceoid);

    /*
     * loop over the definition list and extract the information we need.
     */
    foreach(pl, parameters)
    {
        DefElem    *defel = (DefElem *) lfirst(pl);

        if (strcmp(defel->defname, "start") == 0)
        {
            values[Anum_pg_ts_parser_prsstart - 1] =
                get_ts_parser_func(defel, Anum_pg_ts_parser_prsstart);
        }
        else if (strcmp(defel->defname, "gettoken") == 0)
        {
            values[Anum_pg_ts_parser_prstoken - 1] =
                get_ts_parser_func(defel, Anum_pg_ts_parser_prstoken);
        }
        else if (strcmp(defel->defname, "end") == 0)
        {
            values[Anum_pg_ts_parser_prsend - 1] =
                get_ts_parser_func(defel, Anum_pg_ts_parser_prsend);
        }
        else if (strcmp(defel->defname, "headline") == 0)
        {
            values[Anum_pg_ts_parser_prsheadline - 1] =
                get_ts_parser_func(defel, Anum_pg_ts_parser_prsheadline);
        }
        else if (strcmp(defel->defname, "lextypes") == 0)
        {
            values[Anum_pg_ts_parser_prslextype - 1] =
                get_ts_parser_func(defel, Anum_pg_ts_parser_prslextype);
        }
        else
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("text search parser parameter \"%s\" not recognized",
                            defel->defname)));
    }

    /*
     * Validation
     */
    if (!OidIsValid(DatumGetObjectId(values[Anum_pg_ts_parser_prsstart - 1])))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("text search parser start method is required")));

    if (!OidIsValid(DatumGetObjectId(values[Anum_pg_ts_parser_prstoken - 1])))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("text search parser gettoken method is required")));

    if (!OidIsValid(DatumGetObjectId(values[Anum_pg_ts_parser_prsend - 1])))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("text search parser end method is required")));

    if (!OidIsValid(DatumGetObjectId(values[Anum_pg_ts_parser_prslextype - 1])))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("text search parser lextypes method is required")));

    /*
     * Looks good, insert
     */
    tup = heap_form_tuple(prsRel->rd_att, values, nulls);

    CatalogTupleInsert(prsRel, tup);

    address = makeParserDependencies(tup);

    /* Post creation hook for new text search parser */
    InvokeObjectPostCreateHook(TSParserRelationId, prsOid, 0);

    heap_freetuple(tup);

    table_close(prsRel, RowExclusiveLock);

    return address;
}

/*
 * Guts of TS parser deletion.
 */
void
RemoveTSParserById(Oid prsId)
{
    Relation    relation;
    HeapTuple   tup;

    relation = table_open(TSParserRelationId, RowExclusiveLock);

    tup = SearchSysCache1(TSPARSEROID, ObjectIdGetDatum(prsId));

    if (!HeapTupleIsValid(tup))
        elog(ERROR, "cache lookup failed for text search parser %u", prsId);

    CatalogTupleDelete(relation, &tup->t_self);

    ReleaseSysCache(tup);

    table_close(relation, RowExclusiveLock);
}

/* ---------------------- TS Dictionary commands -----------------------*/

/*
 * make pg_depend entries for a new pg_ts_dict entry
 *
 * Return value is address of the new entry
 */
static ObjectAddress
makeDictionaryDependencies(HeapTuple tuple)
{
    Form_pg_ts_dict dict = (Form_pg_ts_dict) GETSTRUCT(tuple);
    ObjectAddress myself,
                referenced;

    myself.classId = TSDictionaryRelationId;
    myself.objectId = dict->oid;
    myself.objectSubId = 0;

    /* dependency on namespace */
    referenced.classId = NamespaceRelationId;
    referenced.objectId = dict->dictnamespace;
    referenced.objectSubId = 0;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

    /* dependency on owner */
    recordDependencyOnOwner(myself.classId, myself.objectId, dict->dictowner);

    /* dependency on extension */
    recordDependencyOnCurrentExtension(&myself, false);

    /* dependency on template */
    referenced.classId = TSTemplateRelationId;
    referenced.objectId = dict->dicttemplate;
    referenced.objectSubId = 0;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

    return myself;
}

/*
 * verify that a template's init method accepts a proposed option list
 */
static void
verify_dictoptions(Oid tmplId, List *dictoptions)
{
    HeapTuple   tup;
    Form_pg_ts_template tform;
    Oid         initmethod;

    /*
     * Suppress this test when running in a standalone backend.  This is a
     * hack to allow initdb to create prefab dictionaries that might not
     * actually be usable in template1's encoding (due to using external files
     * that can't be translated into template1's encoding).  We want to create
     * them anyway, since they might be usable later in other databases.
     */
    if (!IsUnderPostmaster)
        return;

    tup = SearchSysCache1(TSTEMPLATEOID, ObjectIdGetDatum(tmplId));
    if (!HeapTupleIsValid(tup)) /* should not happen */
        elog(ERROR, "cache lookup failed for text search template %u",
             tmplId);
    tform = (Form_pg_ts_template) GETSTRUCT(tup);

    initmethod = tform->tmplinit;

    if (!OidIsValid(initmethod))
    {
        /* If there is no init method, disallow any options */
        if (dictoptions)
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("text search template \"%s\" does not accept options",
                            NameStr(tform->tmplname))));
    }
    else
    {
        /*
         * Copy the options just in case init method thinks it can scribble on
         * them ...
         */
        dictoptions = copyObject(dictoptions);

        /*
         * Call the init method and see if it complains.  We don't worry about
         * it leaking memory, since our command will soon be over anyway.
         */
        (void) OidFunctionCall1(initmethod, PointerGetDatum(dictoptions));
    }

    ReleaseSysCache(tup);
}

/*
 * CREATE TEXT SEARCH DICTIONARY
 */
ObjectAddress
DefineTSDictionary(List *names, List *parameters)
{
    ListCell   *pl;
    Relation    dictRel;
    HeapTuple   tup;
    Datum       values[Natts_pg_ts_dict];
    bool        nulls[Natts_pg_ts_dict];
    NameData    dname;
    Oid         templId = InvalidOid;
    List       *dictoptions = NIL;
    Oid         dictOid;
    Oid         namespaceoid;
    AclResult   aclresult;
    char       *dictname;
    ObjectAddress address;

    /* Convert list of names to a name and namespace */
    namespaceoid = QualifiedNameGetCreationNamespace(names, &dictname);

    /* Check we have creation rights in target namespace */
    aclresult = pg_namespace_aclcheck(namespaceoid, GetUserId(), ACL_CREATE);
    if (aclresult != ACLCHECK_OK)
        aclcheck_error(aclresult, OBJECT_SCHEMA,
                       get_namespace_name(namespaceoid));

    /*
     * loop over the definition list and extract the information we need.
     */
    foreach(pl, parameters)
    {
        DefElem    *defel = (DefElem *) lfirst(pl);

        if (strcmp(defel->defname, "template") == 0)
        {
            templId = get_ts_template_oid(defGetQualifiedName(defel), false);
        }
        else
        {
            /* Assume it's an option for the dictionary itself */
            dictoptions = lappend(dictoptions, defel);
        }
    }

    /*
     * Validation
     */
    if (!OidIsValid(templId))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("text search template is required")));

    verify_dictoptions(templId, dictoptions);


    dictRel = table_open(TSDictionaryRelationId, RowExclusiveLock);

    /*
     * Looks good, insert
     */
    memset(values, 0, sizeof(values));
    memset(nulls, false, sizeof(nulls));

    dictOid = GetNewOidWithIndex(dictRel, TSDictionaryOidIndexId,
                                 Anum_pg_ts_dict_oid);
    values[Anum_pg_ts_dict_oid - 1] = ObjectIdGetDatum(dictOid);
    namestrcpy(&dname, dictname);
    values[Anum_pg_ts_dict_dictname - 1] = NameGetDatum(&dname);
    values[Anum_pg_ts_dict_dictnamespace - 1] = ObjectIdGetDatum(namespaceoid);
    values[Anum_pg_ts_dict_dictowner - 1] = ObjectIdGetDatum(GetUserId());
    values[Anum_pg_ts_dict_dicttemplate - 1] = ObjectIdGetDatum(templId);
    if (dictoptions)
        values[Anum_pg_ts_dict_dictinitoption - 1] =
            PointerGetDatum(serialize_deflist(dictoptions));
    else
        nulls[Anum_pg_ts_dict_dictinitoption - 1] = true;

    tup = heap_form_tuple(dictRel->rd_att, values, nulls);

    CatalogTupleInsert(dictRel, tup);

    address = makeDictionaryDependencies(tup);

    /* Post creation hook for new text search dictionary */
    InvokeObjectPostCreateHook(TSDictionaryRelationId, dictOid, 0);

    heap_freetuple(tup);

    table_close(dictRel, RowExclusiveLock);

    return address;
}

/*
 * Guts of TS dictionary deletion.
 */
void
RemoveTSDictionaryById(Oid dictId)
{
    Relation    relation;
    HeapTuple   tup;

    relation = table_open(TSDictionaryRelationId, RowExclusiveLock);

    tup = SearchSysCache1(TSDICTOID, ObjectIdGetDatum(dictId));

    if (!HeapTupleIsValid(tup))
        elog(ERROR, "cache lookup failed for text search dictionary %u",
             dictId);

    CatalogTupleDelete(relation, &tup->t_self);

    ReleaseSysCache(tup);

    table_close(relation, RowExclusiveLock);
}

/*
 * ALTER TEXT SEARCH DICTIONARY
 */
ObjectAddress
AlterTSDictionary(AlterTSDictionaryStmt *stmt)
{
    HeapTuple   tup,
                newtup;
    Relation    rel;
    Oid         dictId;
    ListCell   *pl;
    List       *dictoptions;
    Datum       opt;
    bool        isnull;
    Datum       repl_val[Natts_pg_ts_dict];
    bool        repl_null[Natts_pg_ts_dict];
    bool        repl_repl[Natts_pg_ts_dict];
    ObjectAddress address;

    dictId = get_ts_dict_oid(stmt->dictname, false);

    rel = table_open(TSDictionaryRelationId, RowExclusiveLock);

    tup = SearchSysCache1(TSDICTOID, ObjectIdGetDatum(dictId));

    if (!HeapTupleIsValid(tup))
        elog(ERROR, "cache lookup failed for text search dictionary %u",
             dictId);

    /* must be owner */
    if (!pg_ts_dict_ownercheck(dictId, GetUserId()))
        aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_TSDICTIONARY,
                       NameListToString(stmt->dictname));

    /* deserialize the existing set of options */
    opt = SysCacheGetAttr(TSDICTOID, tup,
                          Anum_pg_ts_dict_dictinitoption,
                          &isnull);
    if (isnull)
        dictoptions = NIL;
    else
        dictoptions = deserialize_deflist(opt);

    /*
     * Modify the options list as per specified changes
     */
    foreach(pl, stmt->options)
    {
        DefElem    *defel = (DefElem *) lfirst(pl);
        ListCell   *cell;

        /*
         * Remove any matches ...
         */
        foreach(cell, dictoptions)
        {
            DefElem    *oldel = (DefElem *) lfirst(cell);

            if (strcmp(oldel->defname, defel->defname) == 0)
                dictoptions = foreach_delete_current(dictoptions, cell);
        }

        /*
         * and add new value if it's got one
         */
        if (defel->arg)
            dictoptions = lappend(dictoptions, defel);
    }

    /*
     * Validate
     */
    verify_dictoptions(((Form_pg_ts_dict) GETSTRUCT(tup))->dicttemplate,
                       dictoptions);

    /*
     * Looks good, update
     */
    memset(repl_val, 0, sizeof(repl_val));
    memset(repl_null, false, sizeof(repl_null));
    memset(repl_repl, false, sizeof(repl_repl));

    if (dictoptions)
        repl_val[Anum_pg_ts_dict_dictinitoption - 1] =
            PointerGetDatum(serialize_deflist(dictoptions));
    else
        repl_null[Anum_pg_ts_dict_dictinitoption - 1] = true;
    repl_repl[Anum_pg_ts_dict_dictinitoption - 1] = true;

    newtup = heap_modify_tuple(tup, RelationGetDescr(rel),
                               repl_val, repl_null, repl_repl);

    CatalogTupleUpdate(rel, &newtup->t_self, newtup);

    InvokeObjectPostAlterHook(TSDictionaryRelationId, dictId, 0);

    ObjectAddressSet(address, TSDictionaryRelationId, dictId);

    /*
     * NOTE: because we only support altering the options, not the template,
     * there is no need to update dependencies.  This might have to change if
     * the options ever reference inside-the-database objects.
     */

    heap_freetuple(newtup);
    ReleaseSysCache(tup);

    table_close(rel, RowExclusiveLock);

    return address;
}

/* ---------------------- TS Template commands -----------------------*/

/*
 * lookup a template support function and return its OID (as a Datum)
 *
 * attnum is the pg_ts_template column the function will go into
 */
static Datum
get_ts_template_func(DefElem *defel, int attnum)
{
    List       *funcName = defGetQualifiedName(defel);
    Oid         typeId[4];
    Oid         retTypeId;
    int         nargs;
    Oid         procOid;

    retTypeId = INTERNALOID;
    typeId[0] = INTERNALOID;
    typeId[1] = INTERNALOID;
    typeId[2] = INTERNALOID;
    typeId[3] = INTERNALOID;
    switch (attnum)
    {
        case Anum_pg_ts_template_tmplinit:
            nargs = 1;
            break;
        case Anum_pg_ts_template_tmpllexize:
            nargs = 4;
            break;
        default:
            /* should not be here */
            elog(ERROR, "unrecognized attribute for text search template: %d",
                 attnum);
            nargs = 0;          /* keep compiler quiet */
    }

    procOid = LookupFuncName(funcName, nargs, typeId, false);
    if (get_func_rettype(procOid) != retTypeId)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("function %s should return type %s",
                        func_signature_string(funcName, nargs, NIL, typeId),
                        format_type_be(retTypeId))));

    return ObjectIdGetDatum(procOid);
}

/*
 * make pg_depend entries for a new pg_ts_template entry
 */
static ObjectAddress
makeTSTemplateDependencies(HeapTuple tuple)
{
    Form_pg_ts_template tmpl = (Form_pg_ts_template) GETSTRUCT(tuple);
    ObjectAddress myself,
                referenced;

    myself.classId = TSTemplateRelationId;
    myself.objectId = tmpl->oid;
    myself.objectSubId = 0;

    /* dependency on namespace */
    referenced.classId = NamespaceRelationId;
    referenced.objectId = tmpl->tmplnamespace;
    referenced.objectSubId = 0;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

    /* dependency on extension */
    recordDependencyOnCurrentExtension(&myself, false);

    /* dependencies on functions */
    referenced.classId = ProcedureRelationId;
    referenced.objectSubId = 0;

    referenced.objectId = tmpl->tmpllexize;
    recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

    if (OidIsValid(tmpl->tmplinit))
    {
        referenced.objectId = tmpl->tmplinit;
        recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
    }

    return myself;
}

/*
 * CREATE TEXT SEARCH TEMPLATE
 */
ObjectAddress
DefineTSTemplate(List *names, List *parameters)
{
    ListCell   *pl;
    Relation    tmplRel;
    HeapTuple   tup;
    Datum       values[Natts_pg_ts_template];
    bool        nulls[Natts_pg_ts_template];
    NameData    dname;
    int         i;
    Oid         tmplOid;
    Oid         namespaceoid;
    char       *tmplname;
    ObjectAddress address;

    if (!superuser())
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be superuser to create text search templates")));

    /* Convert list of names to a name and namespace */
    namespaceoid = QualifiedNameGetCreationNamespace(names, &tmplname);

    tmplRel = table_open(TSTemplateRelationId, RowExclusiveLock);

    for (i = 0; i < Natts_pg_ts_template; i++)
    {
        nulls[i] = false;
        values[i] = ObjectIdGetDatum(InvalidOid);
    }

    tmplOid = GetNewOidWithIndex(tmplRel, TSTemplateOidIndexId,
                                 Anum_pg_ts_dict_oid);
    values[Anum_pg_ts_template_oid - 1] = ObjectIdGetDatum(tmplOid);
    namestrcpy(&dname, tmplname);
    values[Anum_pg_ts_template_tmplname - 1] = NameGetDatum(&dname);
    values[Anum_pg_ts_template_tmplnamespace - 1] = ObjectIdGetDatum(namespaceoid);

    /*
     * loop over the definition list and extract the information we need.
     */
    foreach(pl, parameters)
    {
        DefElem    *defel = (DefElem *) lfirst(pl);

        if (strcmp(defel->defname, "init") == 0)
        {
            values[Anum_pg_ts_template_tmplinit - 1] =
                get_ts_template_func(defel, Anum_pg_ts_template_tmplinit);
            nulls[Anum_pg_ts_template_tmplinit - 1] = false;
        }
        else if (strcmp(defel->defname, "lexize") == 0)
        {
            values[Anum_pg_ts_template_tmpllexize - 1] =
                get_ts_template_func(defel, Anum_pg_ts_template_tmpllexize);
            nulls[Anum_pg_ts_template_tmpllexize - 1] = false;
        }
        else
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("text search template parameter \"%s\" not recognized",
                            defel->defname)));
    }

    /*
     * Validation
     */
    if (!OidIsValid(DatumGetObjectId(values[Anum_pg_ts_template_tmpllexize - 1])))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("text search template lexize method is required")));

    /*
     * Looks good, insert
     */
    tup = heap_form_tuple(tmplRel->rd_att, values, nulls);

    CatalogTupleInsert(tmplRel, tup);

    address = makeTSTemplateDependencies(tup);

    /* Post creation hook for new text search template */
    InvokeObjectPostCreateHook(TSTemplateRelationId, tmplOid, 0);

    heap_freetuple(tup);

    table_close(tmplRel, RowExclusiveLock);

    return address;
}

/*
 * Guts of TS template deletion.
 */
void
RemoveTSTemplateById(Oid tmplId)
{
    Relation    relation;
    HeapTuple   tup;

    relation = table_open(TSTemplateRelationId, RowExclusiveLock);

    tup = SearchSysCache1(TSTEMPLATEOID, ObjectIdGetDatum(tmplId));

    if (!HeapTupleIsValid(tup))
        elog(ERROR, "cache lookup failed for text search template %u",
             tmplId);

    CatalogTupleDelete(relation, &tup->t_self);

    ReleaseSysCache(tup);

    table_close(relation, RowExclusiveLock);
}

/* ---------------------- TS Configuration commands -----------------------*/

/*
 * Finds syscache tuple of configuration.
 * Returns NULL if no such cfg.
 */
static HeapTuple
GetTSConfigTuple(List *names)
{
    HeapTuple   tup;
    Oid         cfgId;

    cfgId = get_ts_config_oid(names, true);
    if (!OidIsValid(cfgId))
        return NULL;

    tup = SearchSysCache1(TSCONFIGOID, ObjectIdGetDatum(cfgId));

    if (!HeapTupleIsValid(tup)) /* should not happen */
        elog(ERROR, "cache lookup failed for text search configuration %u",
             cfgId);

    return tup;
}

/*
 * make pg_depend entries for a new or updated pg_ts_config entry
 *
 * Pass opened pg_ts_config_map relation if there might be any config map
 * entries for the config.
 */
static ObjectAddress
makeConfigurationDependencies(HeapTuple tuple, bool removeOld,
                              Relation mapRel)
{
    Form_pg_ts_config cfg = (Form_pg_ts_config) GETSTRUCT(tuple);
    ObjectAddresses *addrs;
    ObjectAddress myself,
                referenced;

    myself.classId = TSConfigRelationId;
    myself.objectId = cfg->oid;
    myself.objectSubId = 0;

    /* for ALTER case, first flush old dependencies, except extension deps */
    if (removeOld)
    {
        deleteDependencyRecordsFor(myself.classId, myself.objectId, true);
        deleteSharedDependencyRecordsFor(myself.classId, myself.objectId, 0);
    }

    /*
     * We use an ObjectAddresses list to remove possible duplicate
     * dependencies from the config map info.  The pg_ts_config items
     * shouldn't be duplicates, but might as well fold them all into one call.
     */
    addrs = new_object_addresses();

    /* dependency on namespace */
    referenced.classId = NamespaceRelationId;
    referenced.objectId = cfg->cfgnamespace;
    referenced.objectSubId = 0;
    add_exact_object_address(&referenced, addrs);

    /* dependency on owner */
    recordDependencyOnOwner(myself.classId, myself.objectId, cfg->cfgowner);

    /* dependency on extension */
    recordDependencyOnCurrentExtension(&myself, removeOld);

    /* dependency on parser */
    referenced.classId = TSParserRelationId;
    referenced.objectId = cfg->cfgparser;
    referenced.objectSubId = 0;
    add_exact_object_address(&referenced, addrs);

    /* dependencies on dictionaries listed in config map */
    if (mapRel)
    {
        ScanKeyData skey;
        SysScanDesc scan;
        HeapTuple   maptup;

        /* CCI to ensure we can see effects of caller's changes */
        CommandCounterIncrement();

        ScanKeyInit(&skey,
                    Anum_pg_ts_config_map_mapcfg,
                    BTEqualStrategyNumber, F_OIDEQ,
                    ObjectIdGetDatum(myself.objectId));

        scan = systable_beginscan(mapRel, TSConfigMapIndexId, true,
                                  NULL, 1, &skey);

        while (HeapTupleIsValid((maptup = systable_getnext(scan))))
        {
            Form_pg_ts_config_map cfgmap = (Form_pg_ts_config_map) GETSTRUCT(maptup);

            referenced.classId = TSDictionaryRelationId;
            referenced.objectId = cfgmap->mapdict;
            referenced.objectSubId = 0;
            add_exact_object_address(&referenced, addrs);
        }

        systable_endscan(scan);
    }

    /* Record 'em (this includes duplicate elimination) */
    record_object_address_dependencies(&myself, addrs, DEPENDENCY_NORMAL);

    free_object_addresses(addrs);

    return myself;
}

/*
 * CREATE TEXT SEARCH CONFIGURATION
 */
ObjectAddress
DefineTSConfiguration(List *names, List *parameters, ObjectAddress *copied)
{
    Relation    cfgRel;
    Relation    mapRel = NULL;
    HeapTuple   tup;
    Datum       values[Natts_pg_ts_config];
    bool        nulls[Natts_pg_ts_config];
    AclResult   aclresult;
    Oid         namespaceoid;
    char       *cfgname;
    NameData    cname;
    Oid         sourceOid = InvalidOid;
    Oid         prsOid = InvalidOid;
    Oid         cfgOid;
    ListCell   *pl;
    ObjectAddress address;

    /* Convert list of names to a name and namespace */
    namespaceoid = QualifiedNameGetCreationNamespace(names, &cfgname);

    /* Check we have creation rights in target namespace */
    aclresult = pg_namespace_aclcheck(namespaceoid, GetUserId(), ACL_CREATE);
    if (aclresult != ACLCHECK_OK)
        aclcheck_error(aclresult, OBJECT_SCHEMA,
                       get_namespace_name(namespaceoid));

    /*
     * loop over the definition list and extract the information we need.
     */
    foreach(pl, parameters)
    {
        DefElem    *defel = (DefElem *) lfirst(pl);

        if (strcmp(defel->defname, "parser") == 0)
            prsOid = get_ts_parser_oid(defGetQualifiedName(defel), false);
        else if (strcmp(defel->defname, "copy") == 0)
            sourceOid = get_ts_config_oid(defGetQualifiedName(defel), false);
        else
            ereport(ERROR,
                    (errcode(ERRCODE_SYNTAX_ERROR),
                     errmsg("text search configuration parameter \"%s\" not recognized",
                            defel->defname)));
    }

    if (OidIsValid(sourceOid) && OidIsValid(prsOid))
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg("cannot specify both PARSER and COPY options")));

    /* make copied tsconfig available to callers */
    if (copied && OidIsValid(sourceOid))
    {
        ObjectAddressSet(*copied,
                         TSConfigRelationId,
                         sourceOid);
    }

    /*
     * Look up source config if given.
     */
    if (OidIsValid(sourceOid))
    {
        Form_pg_ts_config cfg;

        tup = SearchSysCache1(TSCONFIGOID, ObjectIdGetDatum(sourceOid));
        if (!HeapTupleIsValid(tup))
            elog(ERROR, "cache lookup failed for text search configuration %u",
                 sourceOid);

        cfg = (Form_pg_ts_config) GETSTRUCT(tup);

        /* use source's parser */
        prsOid = cfg->cfgparser;

        ReleaseSysCache(tup);
    }

    /*
     * Validation
     */
    if (!OidIsValid(prsOid))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("text search parser is required")));

    cfgRel = table_open(TSConfigRelationId, RowExclusiveLock);

    /*
     * Looks good, build tuple and insert
     */
    memset(values, 0, sizeof(values));
    memset(nulls, false, sizeof(nulls));

    cfgOid = GetNewOidWithIndex(cfgRel, TSConfigOidIndexId,
                                Anum_pg_ts_config_oid);
    values[Anum_pg_ts_config_oid - 1] = ObjectIdGetDatum(cfgOid);
    namestrcpy(&cname, cfgname);
    values[Anum_pg_ts_config_cfgname - 1] = NameGetDatum(&cname);
    values[Anum_pg_ts_config_cfgnamespace - 1] = ObjectIdGetDatum(namespaceoid);
    values[Anum_pg_ts_config_cfgowner - 1] = ObjectIdGetDatum(GetUserId());
    values[Anum_pg_ts_config_cfgparser - 1] = ObjectIdGetDatum(prsOid);

    tup = heap_form_tuple(cfgRel->rd_att, values, nulls);

    CatalogTupleInsert(cfgRel, tup);

    if (OidIsValid(sourceOid))
    {
        /*
         * Copy token-dicts map from source config
         */
        ScanKeyData skey;
        SysScanDesc scan;
        HeapTuple   maptup;

        mapRel = table_open(TSConfigMapRelationId, RowExclusiveLock);

        ScanKeyInit(&skey,
                    Anum_pg_ts_config_map_mapcfg,
                    BTEqualStrategyNumber, F_OIDEQ,
                    ObjectIdGetDatum(sourceOid));

        scan = systable_beginscan(mapRel, TSConfigMapIndexId, true,
                                  NULL, 1, &skey);

        while (HeapTupleIsValid((maptup = systable_getnext(scan))))
        {
            Form_pg_ts_config_map cfgmap = (Form_pg_ts_config_map) GETSTRUCT(maptup);
            HeapTuple   newmaptup;
            Datum       mapvalues[Natts_pg_ts_config_map];
            bool        mapnulls[Natts_pg_ts_config_map];

            memset(mapvalues, 0, sizeof(mapvalues));
            memset(mapnulls, false, sizeof(mapnulls));

            mapvalues[Anum_pg_ts_config_map_mapcfg - 1] = cfgOid;
            mapvalues[Anum_pg_ts_config_map_maptokentype - 1] = cfgmap->maptokentype;
            mapvalues[Anum_pg_ts_config_map_mapseqno - 1] = cfgmap->mapseqno;
            mapvalues[Anum_pg_ts_config_map_mapdict - 1] = cfgmap->mapdict;

            newmaptup = heap_form_tuple(mapRel->rd_att, mapvalues, mapnulls);

            CatalogTupleInsert(mapRel, newmaptup);

            heap_freetuple(newmaptup);
        }

        systable_endscan(scan);
    }

    address = makeConfigurationDependencies(tup, false, mapRel);

    /* Post creation hook for new text search configuration */
    InvokeObjectPostCreateHook(TSConfigRelationId, cfgOid, 0);

    heap_freetuple(tup);

    if (mapRel)
        table_close(mapRel, RowExclusiveLock);
    table_close(cfgRel, RowExclusiveLock);

    return address;
}

/*
 * Guts of TS configuration deletion.
 */
void
RemoveTSConfigurationById(Oid cfgId)
{
    Relation    relCfg,
                relMap;
    HeapTuple   tup;
    ScanKeyData skey;
    SysScanDesc scan;

    /* Remove the pg_ts_config entry */
    relCfg = table_open(TSConfigRelationId, RowExclusiveLock);

    tup = SearchSysCache1(TSCONFIGOID, ObjectIdGetDatum(cfgId));

    if (!HeapTupleIsValid(tup))
        elog(ERROR, "cache lookup failed for text search dictionary %u",
             cfgId);

    CatalogTupleDelete(relCfg, &tup->t_self);

    ReleaseSysCache(tup);

    table_close(relCfg, RowExclusiveLock);

    /* Remove any pg_ts_config_map entries */
    relMap = table_open(TSConfigMapRelationId, RowExclusiveLock);

    ScanKeyInit(&skey,
                Anum_pg_ts_config_map_mapcfg,
                BTEqualStrategyNumber, F_OIDEQ,
                ObjectIdGetDatum(cfgId));

    scan = systable_beginscan(relMap, TSConfigMapIndexId, true,
                              NULL, 1, &skey);

    while (HeapTupleIsValid((tup = systable_getnext(scan))))
    {
        CatalogTupleDelete(relMap, &tup->t_self);
    }

    systable_endscan(scan);

    table_close(relMap, RowExclusiveLock);
}

/*
 * ALTER TEXT SEARCH CONFIGURATION - main entry point
 */
ObjectAddress
AlterTSConfiguration(AlterTSConfigurationStmt *stmt)
{
    HeapTuple   tup;
    Oid         cfgId;
    Relation    relMap;
    ObjectAddress address;

    /* Find the configuration */
    tup = GetTSConfigTuple(stmt->cfgname);
    if (!HeapTupleIsValid(tup))
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("text search configuration \"%s\" does not exist",
                        NameListToString(stmt->cfgname))));

    cfgId = ((Form_pg_ts_config) GETSTRUCT(tup))->oid;

    /* must be owner */
    if (!pg_ts_config_ownercheck(cfgId, GetUserId()))
        aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_TSCONFIGURATION,
                       NameListToString(stmt->cfgname));

    relMap = table_open(TSConfigMapRelationId, RowExclusiveLock);

    /* Add or drop mappings */
    if (stmt->dicts)
        MakeConfigurationMapping(stmt, tup, relMap);
    else if (stmt->tokentype)
        DropConfigurationMapping(stmt, tup, relMap);

    /* Update dependencies */
    makeConfigurationDependencies(tup, true, relMap);

    InvokeObjectPostAlterHook(TSConfigRelationId, cfgId, 0);

    ObjectAddressSet(address, TSConfigRelationId, cfgId);

    table_close(relMap, RowExclusiveLock);

    ReleaseSysCache(tup);

    return address;
}

/*
 * Translate a list of token type names to an array of token type numbers
 */
static int *
getTokenTypes(Oid prsId, List *tokennames)
{
    TSParserCacheEntry *prs = lookup_ts_parser_cache(prsId);
    LexDescr   *list;
    int        *res,
                i,
                ntoken;
    ListCell   *tn;

    ntoken = list_length(tokennames);
    if (ntoken == 0)
        return NULL;
    res = (int *) palloc(sizeof(int) * ntoken);

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

    /* lextype takes one dummy argument */
    list = (LexDescr *) DatumGetPointer(OidFunctionCall1(prs->lextypeOid,
                                                         (Datum) 0));

    i = 0;
    foreach(tn, tokennames)
    {
        Value      *val = (Value *) lfirst(tn);
        bool        found = false;
        int         j;

        j = 0;
        while (list && list[j].lexid)
        {
            if (strcmp(strVal(val), list[j].alias) == 0)
            {
                res[i] = list[j].lexid;
                found = true;
                break;
            }
            j++;
        }
        if (!found)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("token type \"%s\" does not exist",
                            strVal(val))));
        i++;
    }

    return res;
}

/*
 * ALTER TEXT SEARCH CONFIGURATION ADD/ALTER MAPPING
 */
static void
MakeConfigurationMapping(AlterTSConfigurationStmt *stmt,
                         HeapTuple tup, Relation relMap)
{
    Form_pg_ts_config tsform;
    Oid         cfgId;
    ScanKeyData skey[2];
    SysScanDesc scan;
    HeapTuple   maptup;
    int         i;
    int         j;
    Oid         prsId;
    int        *tokens,
                ntoken;
    Oid        *dictIds;
    int         ndict;
    ListCell   *c;

    tsform = (Form_pg_ts_config) GETSTRUCT(tup);
    cfgId = tsform->oid;
    prsId = tsform->cfgparser;

    tokens = getTokenTypes(prsId, stmt->tokentype);
    ntoken = list_length(stmt->tokentype);

    if (stmt->override)
    {
        /*
         * delete maps for tokens if they exist and command was ALTER
         */
        for (i = 0; i < ntoken; i++)
        {
            ScanKeyInit(&skey[0],
                        Anum_pg_ts_config_map_mapcfg,
                        BTEqualStrategyNumber, F_OIDEQ,
                        ObjectIdGetDatum(cfgId));
            ScanKeyInit(&skey[1],
                        Anum_pg_ts_config_map_maptokentype,
                        BTEqualStrategyNumber, F_INT4EQ,
                        Int32GetDatum(tokens[i]));

            scan = systable_beginscan(relMap, TSConfigMapIndexId, true,
                                      NULL, 2, skey);

            while (HeapTupleIsValid((maptup = systable_getnext(scan))))
            {
                CatalogTupleDelete(relMap, &maptup->t_self);
            }

            systable_endscan(scan);
        }
    }

    /*
     * Convert list of dictionary names to array of dict OIDs
     */
    ndict = list_length(stmt->dicts);
    dictIds = (Oid *) palloc(sizeof(Oid) * ndict);
    i = 0;
    foreach(c, stmt->dicts)
    {
        List       *names = (List *) lfirst(c);

        dictIds[i] = get_ts_dict_oid(names, false);
        i++;
    }

    if (stmt->replace)
    {
        /*
         * Replace a specific dictionary in existing entries
         */
        Oid         dictOld = dictIds[0],
                    dictNew = dictIds[1];

        ScanKeyInit(&skey[0],
                    Anum_pg_ts_config_map_mapcfg,
                    BTEqualStrategyNumber, F_OIDEQ,
                    ObjectIdGetDatum(cfgId));

        scan = systable_beginscan(relMap, TSConfigMapIndexId, true,
                                  NULL, 1, skey);

        while (HeapTupleIsValid((maptup = systable_getnext(scan))))
        {
            Form_pg_ts_config_map cfgmap = (Form_pg_ts_config_map) GETSTRUCT(maptup);

            /*
             * check if it's one of target token types
             */
            if (tokens)
            {
                bool        tokmatch = false;

                for (j = 0; j < ntoken; j++)
                {
                    if (cfgmap->maptokentype == tokens[j])
                    {
                        tokmatch = true;
                        break;
                    }
                }
                if (!tokmatch)
                    continue;
            }

            /*
             * replace dictionary if match
             */
            if (cfgmap->mapdict == dictOld)
            {
                Datum       repl_val[Natts_pg_ts_config_map];
                bool        repl_null[Natts_pg_ts_config_map];
                bool        repl_repl[Natts_pg_ts_config_map];
                HeapTuple   newtup;

                memset(repl_val, 0, sizeof(repl_val));
                memset(repl_null, false, sizeof(repl_null));
                memset(repl_repl, false, sizeof(repl_repl));

                repl_val[Anum_pg_ts_config_map_mapdict - 1] = ObjectIdGetDatum(dictNew);
                repl_repl[Anum_pg_ts_config_map_mapdict - 1] = true;

                newtup = heap_modify_tuple(maptup,
                                           RelationGetDescr(relMap),
                                           repl_val, repl_null, repl_repl);
                CatalogTupleUpdate(relMap, &newtup->t_self, newtup);
            }
        }

        systable_endscan(scan);
    }
    else
    {
        /*
         * Insertion of new entries
         */
        for (i = 0; i < ntoken; i++)
        {
            for (j = 0; j < ndict; j++)
            {
                Datum       values[Natts_pg_ts_config_map];
                bool        nulls[Natts_pg_ts_config_map];

                memset(nulls, false, sizeof(nulls));
                values[Anum_pg_ts_config_map_mapcfg - 1] = ObjectIdGetDatum(cfgId);
                values[Anum_pg_ts_config_map_maptokentype - 1] = Int32GetDatum(tokens[i]);
                values[Anum_pg_ts_config_map_mapseqno - 1] = Int32GetDatum(j + 1);
                values[Anum_pg_ts_config_map_mapdict - 1] = ObjectIdGetDatum(dictIds[j]);

                tup = heap_form_tuple(relMap->rd_att, values, nulls);
                CatalogTupleInsert(relMap, tup);

                heap_freetuple(tup);
            }
        }
    }

    EventTriggerCollectAlterTSConfig(stmt, cfgId, dictIds, ndict);
}

/*
 * ALTER TEXT SEARCH CONFIGURATION DROP MAPPING
 */
static void
DropConfigurationMapping(AlterTSConfigurationStmt *stmt,
                         HeapTuple tup, Relation relMap)
{
    Form_pg_ts_config tsform;
    Oid         cfgId;
    ScanKeyData skey[2];
    SysScanDesc scan;
    HeapTuple   maptup;
    int         i;
    Oid         prsId;
    int        *tokens;
    ListCell   *c;

    tsform = (Form_pg_ts_config) GETSTRUCT(tup);
    cfgId = tsform->oid;
    prsId = tsform->cfgparser;

    tokens = getTokenTypes(prsId, stmt->tokentype);

    i = 0;
    foreach(c, stmt->tokentype)
    {
        Value      *val = (Value *) lfirst(c);
        bool        found = false;

        ScanKeyInit(&skey[0],
                    Anum_pg_ts_config_map_mapcfg,
                    BTEqualStrategyNumber, F_OIDEQ,
                    ObjectIdGetDatum(cfgId));
        ScanKeyInit(&skey[1],
                    Anum_pg_ts_config_map_maptokentype,
                    BTEqualStrategyNumber, F_INT4EQ,
                    Int32GetDatum(tokens[i]));

        scan = systable_beginscan(relMap, TSConfigMapIndexId, true,
                                  NULL, 2, skey);

        while (HeapTupleIsValid((maptup = systable_getnext(scan))))
        {
            CatalogTupleDelete(relMap, &maptup->t_self);
            found = true;
        }

        systable_endscan(scan);

        if (!found)
        {
            if (!stmt->missing_ok)
            {
                ereport(ERROR,
                        (errcode(ERRCODE_UNDEFINED_OBJECT),
                         errmsg("mapping for token type \"%s\" does not exist",
                                strVal(val))));
            }
            else
            {
                ereport(NOTICE,
                        (errmsg("mapping for token type \"%s\" does not exist, skipping",
                                strVal(val))));
            }
        }

        i++;
    }

    EventTriggerCollectAlterTSConfig(stmt, cfgId, NULL, 0);
}


/*
 * Serialize dictionary options, producing a TEXT datum from a List of DefElem
 *
 * This is used to form the value stored in pg_ts_dict.dictinitoption.
 * For the convenience of pg_dump, the output is formatted exactly as it
 * would need to appear in CREATE TEXT SEARCH DICTIONARY to reproduce the
 * same options.
 *
 * Note that we assume that only the textual representation of an option's
 * value is interesting --- hence, non-string DefElems get forced to strings.
 */
text *
serialize_deflist(List *deflist)
{
    text       *result;
    StringInfoData buf;
    ListCell   *l;

    initStringInfo(&buf);

    foreach(l, deflist)
    {
        DefElem    *defel = (DefElem *) lfirst(l);
        char       *val = defGetString(defel);

        appendStringInfo(&buf, "%s = ",
                         quote_identifier(defel->defname));
        /* If backslashes appear, force E syntax to determine their handling */
        if (strchr(val, '\\'))
            appendStringInfoChar(&buf, ESCAPE_STRING_SYNTAX);
        appendStringInfoChar(&buf, '\'');
        while (*val)
        {
            char        ch = *val++;

            if (SQL_STR_DOUBLE(ch, true))
                appendStringInfoChar(&buf, ch);
            appendStringInfoChar(&buf, ch);
        }
        appendStringInfoChar(&buf, '\'');
        if (lnext(deflist, l) != NULL)
            appendStringInfoString(&buf, ", ");
    }

    result = cstring_to_text_with_len(buf.data, buf.len);
    pfree(buf.data);
    return result;
}

/*
 * Deserialize dictionary options, reconstructing a List of DefElem from TEXT
 *
 * This is also used for prsheadline options, so for backward compatibility
 * we need to accept a few things serialize_deflist() will never emit:
 * in particular, unquoted and double-quoted values.
 */
List *
deserialize_deflist(Datum txt)
{
    text       *in = DatumGetTextPP(txt);   /* in case it's toasted */
    List       *result = NIL;
    int         len = VARSIZE_ANY_EXHDR(in);
    char       *ptr,
               *endptr,
               *workspace,
               *wsptr = NULL,
               *startvalue = NULL;
    typedef enum
    {
        CS_WAITKEY,
        CS_INKEY,
        CS_INQKEY,
        CS_WAITEQ,
        CS_WAITVALUE,
        CS_INSQVALUE,
        CS_INDQVALUE,
        CS_INWVALUE
    } ds_state;
    ds_state    state = CS_WAITKEY;

    workspace = (char *) palloc(len + 1);   /* certainly enough room */
    ptr = VARDATA_ANY(in);
    endptr = ptr + len;
    for (; ptr < endptr; ptr++)
    {
        switch (state)
        {
            case CS_WAITKEY:
                if (isspace((unsigned char) *ptr) || *ptr == ',')
                    continue;
                if (*ptr == '"')
                {
                    wsptr = workspace;
                    state = CS_INQKEY;
                }
                else
                {
                    wsptr = workspace;
                    *wsptr++ = *ptr;
                    state = CS_INKEY;
                }
                break;
            case CS_INKEY:
                if (isspace((unsigned char) *ptr))
                {
                    *wsptr++ = '\0';
                    state = CS_WAITEQ;
                }
                else if (*ptr == '=')
                {
                    *wsptr++ = '\0';
                    state = CS_WAITVALUE;
                }
                else
                {
                    *wsptr++ = *ptr;
                }
                break;
            case CS_INQKEY:
                if (*ptr == '"')
                {
                    if (ptr + 1 < endptr && ptr[1] == '"')
                    {
                        /* copy only one of the two quotes */
                        *wsptr++ = *ptr++;
                    }
                    else
                    {
                        *wsptr++ = '\0';
                        state = CS_WAITEQ;
                    }
                }
                else
                {
                    *wsptr++ = *ptr;
                }
                break;
            case CS_WAITEQ:
                if (*ptr == '=')
                    state = CS_WAITVALUE;
                else if (!isspace((unsigned char) *ptr))
                    ereport(ERROR,
                            (errcode(ERRCODE_SYNTAX_ERROR),
                             errmsg("invalid parameter list format: \"%s\"",
                                    text_to_cstring(in))));
                break;
            case CS_WAITVALUE:
                if (*ptr == '\'')
                {
                    startvalue = wsptr;
                    state = CS_INSQVALUE;
                }
                else if (*ptr == 'E' && ptr + 1 < endptr && ptr[1] == '\'')
                {
                    ptr++;
                    startvalue = wsptr;
                    state = CS_INSQVALUE;
                }
                else if (*ptr == '"')
                {
                    startvalue = wsptr;
                    state = CS_INDQVALUE;
                }
                else if (!isspace((unsigned char) *ptr))
                {
                    startvalue = wsptr;
                    *wsptr++ = *ptr;
                    state = CS_INWVALUE;
                }
                break;
            case CS_INSQVALUE:
                if (*ptr == '\'')
                {
                    if (ptr + 1 < endptr && ptr[1] == '\'')
                    {
                        /* copy only one of the two quotes */
                        *wsptr++ = *ptr++;
                    }
                    else
                    {
                        *wsptr++ = '\0';
                        result = lappend(result,
                                         makeDefElem(pstrdup(workspace),
                                                     (Node *) makeString(pstrdup(startvalue)), -1));
                        state = CS_WAITKEY;
                    }
                }
                else if (*ptr == '\\')
                {
                    if (ptr + 1 < endptr && ptr[1] == '\\')
                    {
                        /* copy only one of the two backslashes */
                        *wsptr++ = *ptr++;
                    }
                    else
                        *wsptr++ = *ptr;
                }
                else
                {
                    *wsptr++ = *ptr;
                }
                break;
            case CS_INDQVALUE:
                if (*ptr == '"')
                {
                    if (ptr + 1 < endptr && ptr[1] == '"')
                    {
                        /* copy only one of the two quotes */
                        *wsptr++ = *ptr++;
                    }
                    else
                    {
                        *wsptr++ = '\0';
                        result = lappend(result,
                                         makeDefElem(pstrdup(workspace),
                                                     (Node *) makeString(pstrdup(startvalue)), -1));
                        state = CS_WAITKEY;
                    }
                }
                else
                {
                    *wsptr++ = *ptr;
                }
                break;
            case CS_INWVALUE:
                if (*ptr == ',' || isspace((unsigned char) *ptr))
                {
                    *wsptr++ = '\0';
                    result = lappend(result,
                                     makeDefElem(pstrdup(workspace),
                                                 (Node *) makeString(pstrdup(startvalue)), -1));
                    state = CS_WAITKEY;
                }
                else
                {
                    *wsptr++ = *ptr;
                }
                break;
            default:
                elog(ERROR, "unrecognized deserialize_deflist state: %d",
                     state);
        }
    }

    if (state == CS_INWVALUE)
    {
        *wsptr++ = '\0';
        result = lappend(result,
                         makeDefElem(pstrdup(workspace),
                                     (Node *) makeString(pstrdup(startvalue)), -1));
    }
    else if (state != CS_WAITKEY)
        ereport(ERROR,
                (errcode(ERRCODE_SYNTAX_ERROR),
                 errmsg("invalid parameter list format: \"%s\"",
                        text_to_cstring(in))));

    pfree(workspace);

    return result;
}