LCOV - code coverage report
Current view: top level - contrib/xml2 - xpath.c (source / functions) Hit Total Coverage
Test: PostgreSQL 18devel Lines: 205 271 75.6 %
Date: 2024-12-02 19:14:57 Functions: 18 21 85.7 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*
       2             :  * contrib/xml2/xpath.c
       3             :  *
       4             :  * Parser interface for DOM-based parser (libxml) rather than
       5             :  * stream-based SAX-type parser
       6             :  */
       7             : #include "postgres.h"
       8             : 
       9             : #include "access/htup_details.h"
      10             : #include "executor/spi.h"
      11             : #include "fmgr.h"
      12             : #include "funcapi.h"
      13             : #include "lib/stringinfo.h"
      14             : #include "utils/builtins.h"
      15             : #include "utils/xml.h"
      16             : 
      17             : /* libxml includes */
      18             : 
      19             : #include <libxml/xpath.h>
      20             : #include <libxml/tree.h>
      21             : #include <libxml/xmlmemory.h>
      22             : #include <libxml/xmlerror.h>
      23             : #include <libxml/parserInternals.h>
      24             : 
      25           2 : PG_MODULE_MAGIC;
      26             : 
      27             : /* exported for use by xslt_proc.c */
      28             : 
      29             : PgXmlErrorContext *pgxml_parser_init(PgXmlStrictness strictness);
      30             : 
      31             : /* workspace for pgxml_xpath() */
      32             : 
      33             : typedef struct
      34             : {
      35             :     xmlDocPtr   doctree;
      36             :     xmlXPathContextPtr ctxt;
      37             :     xmlXPathObjectPtr res;
      38             : } xpath_workspace;
      39             : 
      40             : /* local declarations */
      41             : 
      42             : static xmlChar *pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
      43             :                                    xmlChar *toptagname, xmlChar *septagname,
      44             :                                    xmlChar *plainsep);
      45             : 
      46             : static text *pgxml_result_to_text(xmlXPathObjectPtr res, xmlChar *toptag,
      47             :                                   xmlChar *septag, xmlChar *plainsep);
      48             : 
      49             : static xmlChar *pgxml_texttoxmlchar(text *textstring);
      50             : 
      51             : static xmlXPathObjectPtr pgxml_xpath(text *document, xmlChar *xpath,
      52             :                                      xpath_workspace *workspace);
      53             : 
      54             : static void cleanup_workspace(xpath_workspace *workspace);
      55             : 
      56             : 
      57             : /*
      58             :  * Initialize for xml parsing.
      59             :  *
      60             :  * As with the underlying pg_xml_init function, calls to this MUST be followed
      61             :  * by a PG_TRY block that guarantees that pg_xml_done is called.
      62             :  */
      63             : PgXmlErrorContext *
      64          22 : pgxml_parser_init(PgXmlStrictness strictness)
      65             : {
      66             :     PgXmlErrorContext *xmlerrcxt;
      67             : 
      68             :     /* Set up error handling (we share the core's error handler) */
      69          22 :     xmlerrcxt = pg_xml_init(strictness);
      70             : 
      71             :     /* Note: we're assuming an elog cannot be thrown by the following calls */
      72             : 
      73             :     /* Initialize libxml */
      74          22 :     xmlInitParser();
      75             : 
      76          22 :     return xmlerrcxt;
      77             : }
      78             : 
      79             : 
      80             : /* Encodes special characters (<, >, &, " and \r) as XML entities */
      81             : 
      82           2 : PG_FUNCTION_INFO_V1(xml_encode_special_chars);
      83             : 
      84             : Datum
      85           0 : xml_encode_special_chars(PG_FUNCTION_ARGS)
      86             : {
      87           0 :     text       *tin = PG_GETARG_TEXT_PP(0);
      88             :     text       *tout;
      89             :     xmlChar    *ts,
      90             :                *tt;
      91             : 
      92           0 :     ts = pgxml_texttoxmlchar(tin);
      93             : 
      94           0 :     tt = xmlEncodeSpecialChars(NULL, ts);
      95             : 
      96           0 :     pfree(ts);
      97             : 
      98           0 :     tout = cstring_to_text((char *) tt);
      99             : 
     100           0 :     xmlFree(tt);
     101             : 
     102           0 :     PG_RETURN_TEXT_P(tout);
     103             : }
     104             : 
     105             : /*
     106             :  * Function translates a nodeset into a text representation
     107             :  *
     108             :  * iterates over each node in the set and calls xmlNodeDump to write it to
     109             :  * an xmlBuffer -from which an xmlChar * string is returned.
     110             :  *
     111             :  * each representation is surrounded by <tagname> ... </tagname>
     112             :  *
     113             :  * plainsep is an ordinary (not tag) separator - if used, then nodes are
     114             :  * cast to string as output method
     115             :  */
     116             : static xmlChar *
     117          10 : pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
     118             :                    xmlChar *toptagname,
     119             :                    xmlChar *septagname,
     120             :                    xmlChar *plainsep)
     121             : {
     122             :     xmlBufferPtr buf;
     123             :     xmlChar    *result;
     124             :     int         i;
     125             : 
     126          10 :     buf = xmlBufferCreate();
     127             : 
     128          10 :     if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
     129             :     {
     130           2 :         xmlBufferWriteChar(buf, "<");
     131           2 :         xmlBufferWriteCHAR(buf, toptagname);
     132           2 :         xmlBufferWriteChar(buf, ">");
     133             :     }
     134          10 :     if (nodeset != NULL)
     135             :     {
     136          30 :         for (i = 0; i < nodeset->nodeNr; i++)
     137             :         {
     138          20 :             if (plainsep != NULL)
     139             :             {
     140           8 :                 xmlBufferWriteCHAR(buf,
     141           8 :                                    xmlXPathCastNodeToString(nodeset->nodeTab[i]));
     142             : 
     143             :                 /* If this isn't the last entry, write the plain sep. */
     144           8 :                 if (i < (nodeset->nodeNr) - 1)
     145           4 :                     xmlBufferWriteChar(buf, (char *) plainsep);
     146             :             }
     147             :             else
     148             :             {
     149          12 :                 if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
     150             :                 {
     151           8 :                     xmlBufferWriteChar(buf, "<");
     152           8 :                     xmlBufferWriteCHAR(buf, septagname);
     153           8 :                     xmlBufferWriteChar(buf, ">");
     154             :                 }
     155          12 :                 xmlNodeDump(buf,
     156          12 :                             nodeset->nodeTab[i]->doc,
     157          12 :                             nodeset->nodeTab[i],
     158             :                             1, 0);
     159             : 
     160          12 :                 if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
     161             :                 {
     162           8 :                     xmlBufferWriteChar(buf, "</");
     163           8 :                     xmlBufferWriteCHAR(buf, septagname);
     164           8 :                     xmlBufferWriteChar(buf, ">");
     165             :                 }
     166             :             }
     167             :         }
     168             :     }
     169             : 
     170          10 :     if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
     171             :     {
     172           2 :         xmlBufferWriteChar(buf, "</");
     173           2 :         xmlBufferWriteCHAR(buf, toptagname);
     174           2 :         xmlBufferWriteChar(buf, ">");
     175             :     }
     176          10 :     result = xmlStrdup(buf->content);
     177          10 :     xmlBufferFree(buf);
     178          10 :     return result;
     179             : }
     180             : 
     181             : 
     182             : /* Translate a PostgreSQL "varlena" -i.e. a variable length parameter
     183             :  * into the libxml2 representation
     184             :  */
     185             : static xmlChar *
     186          26 : pgxml_texttoxmlchar(text *textstring)
     187             : {
     188          26 :     return (xmlChar *) text_to_cstring(textstring);
     189             : }
     190             : 
     191             : /* Publicly visible XPath functions */
     192             : 
     193             : /*
     194             :  * This is a "raw" xpath function. Check that it returns child elements
     195             :  * properly
     196             :  */
     197           4 : PG_FUNCTION_INFO_V1(xpath_nodeset);
     198             : 
     199             : Datum
     200           6 : xpath_nodeset(PG_FUNCTION_ARGS)
     201             : {
     202           6 :     text       *document = PG_GETARG_TEXT_PP(0);
     203           6 :     text       *xpathsupp = PG_GETARG_TEXT_PP(1);   /* XPath expression */
     204           6 :     xmlChar    *toptag = pgxml_texttoxmlchar(PG_GETARG_TEXT_PP(2));
     205           6 :     xmlChar    *septag = pgxml_texttoxmlchar(PG_GETARG_TEXT_PP(3));
     206             :     xmlChar    *xpath;
     207             :     text       *xpres;
     208             :     xmlXPathObjectPtr res;
     209             :     xpath_workspace workspace;
     210             : 
     211           6 :     xpath = pgxml_texttoxmlchar(xpathsupp);
     212             : 
     213           6 :     res = pgxml_xpath(document, xpath, &workspace);
     214             : 
     215           6 :     xpres = pgxml_result_to_text(res, toptag, septag, NULL);
     216             : 
     217           6 :     cleanup_workspace(&workspace);
     218             : 
     219           6 :     pfree(xpath);
     220             : 
     221           6 :     if (xpres == NULL)
     222           0 :         PG_RETURN_NULL();
     223           6 :     PG_RETURN_TEXT_P(xpres);
     224             : }
     225             : 
     226             : /*
     227             :  * The following function is almost identical, but returns the elements in
     228             :  * a list.
     229             :  */
     230           4 : PG_FUNCTION_INFO_V1(xpath_list);
     231             : 
     232             : Datum
     233           4 : xpath_list(PG_FUNCTION_ARGS)
     234             : {
     235           4 :     text       *document = PG_GETARG_TEXT_PP(0);
     236           4 :     text       *xpathsupp = PG_GETARG_TEXT_PP(1);   /* XPath expression */
     237           4 :     xmlChar    *plainsep = pgxml_texttoxmlchar(PG_GETARG_TEXT_PP(2));
     238             :     xmlChar    *xpath;
     239             :     text       *xpres;
     240             :     xmlXPathObjectPtr res;
     241             :     xpath_workspace workspace;
     242             : 
     243           4 :     xpath = pgxml_texttoxmlchar(xpathsupp);
     244             : 
     245           4 :     res = pgxml_xpath(document, xpath, &workspace);
     246             : 
     247           4 :     xpres = pgxml_result_to_text(res, NULL, NULL, plainsep);
     248             : 
     249           4 :     cleanup_workspace(&workspace);
     250             : 
     251           4 :     pfree(xpath);
     252             : 
     253           4 :     if (xpres == NULL)
     254           0 :         PG_RETURN_NULL();
     255           4 :     PG_RETURN_TEXT_P(xpres);
     256             : }
     257             : 
     258             : 
     259           4 : PG_FUNCTION_INFO_V1(xpath_string);
     260             : 
     261             : Datum
     262           2 : xpath_string(PG_FUNCTION_ARGS)
     263             : {
     264           2 :     text       *document = PG_GETARG_TEXT_PP(0);
     265           2 :     text       *xpathsupp = PG_GETARG_TEXT_PP(1);   /* XPath expression */
     266             :     xmlChar    *xpath;
     267             :     int32       pathsize;
     268             :     text       *xpres;
     269             :     xmlXPathObjectPtr res;
     270             :     xpath_workspace workspace;
     271             : 
     272           2 :     pathsize = VARSIZE_ANY_EXHDR(xpathsupp);
     273             : 
     274             :     /*
     275             :      * We encapsulate the supplied path with "string()" = 8 chars + 1 for NUL
     276             :      * at end
     277             :      */
     278             :     /* We could try casting to string using the libxml function? */
     279             : 
     280           2 :     xpath = (xmlChar *) palloc(pathsize + 9);
     281           2 :     memcpy((char *) xpath, "string(", 7);
     282           2 :     memcpy((char *) (xpath + 7), VARDATA_ANY(xpathsupp), pathsize);
     283           2 :     xpath[pathsize + 7] = ')';
     284           2 :     xpath[pathsize + 8] = '\0';
     285             : 
     286           2 :     res = pgxml_xpath(document, xpath, &workspace);
     287             : 
     288           2 :     xpres = pgxml_result_to_text(res, NULL, NULL, NULL);
     289             : 
     290           2 :     cleanup_workspace(&workspace);
     291             : 
     292           2 :     pfree(xpath);
     293             : 
     294           2 :     if (xpres == NULL)
     295           2 :         PG_RETURN_NULL();
     296           0 :     PG_RETURN_TEXT_P(xpres);
     297             : }
     298             : 
     299             : 
     300           2 : PG_FUNCTION_INFO_V1(xpath_number);
     301             : 
     302             : Datum
     303           0 : xpath_number(PG_FUNCTION_ARGS)
     304             : {
     305           0 :     text       *document = PG_GETARG_TEXT_PP(0);
     306           0 :     text       *xpathsupp = PG_GETARG_TEXT_PP(1);   /* XPath expression */
     307             :     xmlChar    *xpath;
     308             :     float4      fRes;
     309             :     xmlXPathObjectPtr res;
     310             :     xpath_workspace workspace;
     311             : 
     312           0 :     xpath = pgxml_texttoxmlchar(xpathsupp);
     313             : 
     314           0 :     res = pgxml_xpath(document, xpath, &workspace);
     315             : 
     316           0 :     pfree(xpath);
     317             : 
     318           0 :     if (res == NULL)
     319           0 :         PG_RETURN_NULL();
     320             : 
     321           0 :     fRes = xmlXPathCastToNumber(res);
     322             : 
     323           0 :     cleanup_workspace(&workspace);
     324             : 
     325           0 :     if (xmlXPathIsNaN(fRes))
     326           0 :         PG_RETURN_NULL();
     327             : 
     328           0 :     PG_RETURN_FLOAT4(fRes);
     329             : }
     330             : 
     331             : 
     332           2 : PG_FUNCTION_INFO_V1(xpath_bool);
     333             : 
     334             : Datum
     335           0 : xpath_bool(PG_FUNCTION_ARGS)
     336             : {
     337           0 :     text       *document = PG_GETARG_TEXT_PP(0);
     338           0 :     text       *xpathsupp = PG_GETARG_TEXT_PP(1);   /* XPath expression */
     339             :     xmlChar    *xpath;
     340             :     int         bRes;
     341             :     xmlXPathObjectPtr res;
     342             :     xpath_workspace workspace;
     343             : 
     344           0 :     xpath = pgxml_texttoxmlchar(xpathsupp);
     345             : 
     346           0 :     res = pgxml_xpath(document, xpath, &workspace);
     347             : 
     348           0 :     pfree(xpath);
     349             : 
     350           0 :     if (res == NULL)
     351           0 :         PG_RETURN_BOOL(false);
     352             : 
     353           0 :     bRes = xmlXPathCastToBoolean(res);
     354             : 
     355           0 :     cleanup_workspace(&workspace);
     356             : 
     357           0 :     PG_RETURN_BOOL(bRes);
     358             : }
     359             : 
     360             : 
     361             : 
     362             : /* Core function to evaluate XPath query */
     363             : 
     364             : static xmlXPathObjectPtr
     365          12 : pgxml_xpath(text *document, xmlChar *xpath, xpath_workspace *workspace)
     366             : {
     367          12 :     int32       docsize = VARSIZE_ANY_EXHDR(document);
     368             :     PgXmlErrorContext *xmlerrcxt;
     369             :     xmlXPathCompExprPtr comppath;
     370             : 
     371          12 :     workspace->doctree = NULL;
     372          12 :     workspace->ctxt = NULL;
     373          12 :     workspace->res = NULL;
     374             : 
     375          12 :     xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
     376             : 
     377          12 :     PG_TRY();
     378             :     {
     379          12 :         workspace->doctree = xmlReadMemory((char *) VARDATA_ANY(document),
     380             :                                            docsize, NULL, NULL,
     381             :                                            XML_PARSE_NOENT);
     382          12 :         if (workspace->doctree != NULL)
     383             :         {
     384          10 :             workspace->ctxt = xmlXPathNewContext(workspace->doctree);
     385          10 :             workspace->ctxt->node = xmlDocGetRootElement(workspace->doctree);
     386             : 
     387             :             /* compile the path */
     388          10 :             comppath = xmlXPathCtxtCompile(workspace->ctxt, xpath);
     389          10 :             if (comppath == NULL)
     390           0 :                 xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
     391             :                             "XPath Syntax Error");
     392             : 
     393             :             /* Now evaluate the path expression. */
     394          10 :             workspace->res = xmlXPathCompiledEval(comppath, workspace->ctxt);
     395             : 
     396          10 :             xmlXPathFreeCompExpr(comppath);
     397             :         }
     398             :     }
     399           0 :     PG_CATCH();
     400             :     {
     401           0 :         cleanup_workspace(workspace);
     402             : 
     403           0 :         pg_xml_done(xmlerrcxt, true);
     404             : 
     405           0 :         PG_RE_THROW();
     406             :     }
     407          12 :     PG_END_TRY();
     408             : 
     409          12 :     if (workspace->res == NULL)
     410           2 :         cleanup_workspace(workspace);
     411             : 
     412          12 :     pg_xml_done(xmlerrcxt, false);
     413             : 
     414          12 :     return workspace->res;
     415             : }
     416             : 
     417             : /* Clean up after processing the result of pgxml_xpath() */
     418             : static void
     419          14 : cleanup_workspace(xpath_workspace *workspace)
     420             : {
     421          14 :     if (workspace->res)
     422          10 :         xmlXPathFreeObject(workspace->res);
     423          14 :     workspace->res = NULL;
     424          14 :     if (workspace->ctxt)
     425          10 :         xmlXPathFreeContext(workspace->ctxt);
     426          14 :     workspace->ctxt = NULL;
     427          14 :     if (workspace->doctree)
     428          10 :         xmlFreeDoc(workspace->doctree);
     429          14 :     workspace->doctree = NULL;
     430          14 : }
     431             : 
     432             : static text *
     433          12 : pgxml_result_to_text(xmlXPathObjectPtr res,
     434             :                      xmlChar *toptag,
     435             :                      xmlChar *septag,
     436             :                      xmlChar *plainsep)
     437             : {
     438             :     xmlChar    *xpresstr;
     439             :     text       *xpres;
     440             : 
     441          12 :     if (res == NULL)
     442           2 :         return NULL;
     443             : 
     444          10 :     switch (res->type)
     445             :     {
     446          10 :         case XPATH_NODESET:
     447          10 :             xpresstr = pgxmlNodeSetToText(res->nodesetval,
     448             :                                           toptag,
     449             :                                           septag, plainsep);
     450          10 :             break;
     451             : 
     452           0 :         case XPATH_STRING:
     453           0 :             xpresstr = xmlStrdup(res->stringval);
     454           0 :             break;
     455             : 
     456           0 :         default:
     457           0 :             elog(NOTICE, "unsupported XQuery result: %d", res->type);
     458           0 :             xpresstr = xmlStrdup((const xmlChar *) "<unsupported/>");
     459             :     }
     460             : 
     461             :     /* Now convert this result back to text */
     462          10 :     xpres = cstring_to_text((char *) xpresstr);
     463             : 
     464             :     /* Free various storage */
     465          10 :     xmlFree(xpresstr);
     466             : 
     467          10 :     return xpres;
     468             : }
     469             : 
     470             : /*
     471             :  * xpath_table is a table function. It needs some tidying (as do the
     472             :  * other functions here!
     473             :  */
     474           4 : PG_FUNCTION_INFO_V1(xpath_table);
     475             : 
     476             : Datum
     477          10 : xpath_table(PG_FUNCTION_ARGS)
     478             : {
     479             :     /* Function parameters */
     480          10 :     char       *pkeyfield = text_to_cstring(PG_GETARG_TEXT_PP(0));
     481          10 :     char       *xmlfield = text_to_cstring(PG_GETARG_TEXT_PP(1));
     482          10 :     char       *relname = text_to_cstring(PG_GETARG_TEXT_PP(2));
     483          10 :     char       *xpathset = text_to_cstring(PG_GETARG_TEXT_PP(3));
     484          10 :     char       *condition = text_to_cstring(PG_GETARG_TEXT_PP(4));
     485             : 
     486             :     /* SPI (input tuple) support */
     487             :     SPITupleTable *tuptable;
     488             :     HeapTuple   spi_tuple;
     489             :     TupleDesc   spi_tupdesc;
     490             : 
     491             : 
     492          10 :     ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
     493             :     AttInMetadata *attinmeta;
     494             : 
     495             :     char      **values;
     496             :     xmlChar   **xpaths;
     497             :     char       *pos;
     498          10 :     const char *pathsep = "|";
     499             : 
     500             :     int         numpaths;
     501             :     int         ret;
     502             :     uint64      proc;
     503             :     int         j;
     504             :     int         rownr;          /* For issuing multiple rows from one original
     505             :                                  * document */
     506             :     bool        had_values;     /* To determine end of nodeset results */
     507             :     StringInfoData query_buf;
     508             :     PgXmlErrorContext *xmlerrcxt;
     509          10 :     volatile xmlDocPtr doctree = NULL;
     510             : 
     511          10 :     InitMaterializedSRF(fcinfo, MAT_SRF_USE_EXPECTED_DESC);
     512             : 
     513             :     /* must have at least one output column (for the pkey) */
     514          10 :     if (rsinfo->setDesc->natts < 1)
     515           0 :         ereport(ERROR,
     516             :                 (errcode(ERRCODE_SYNTAX_ERROR),
     517             :                  errmsg("xpath_table must have at least one output column")));
     518             : 
     519             :     /*
     520             :      * At the moment we assume that the returned attributes make sense for the
     521             :      * XPath specified (i.e. we trust the caller). It's not fatal if they get
     522             :      * it wrong - the input function for the column type will raise an error
     523             :      * if the path result can't be converted into the correct binary
     524             :      * representation.
     525             :      */
     526             : 
     527          10 :     attinmeta = TupleDescGetAttInMetadata(rsinfo->setDesc);
     528             : 
     529          10 :     values = (char **) palloc(rsinfo->setDesc->natts * sizeof(char *));
     530          10 :     xpaths = (xmlChar **) palloc(rsinfo->setDesc->natts * sizeof(xmlChar *));
     531             : 
     532             :     /*
     533             :      * Split XPaths. xpathset is a writable CString.
     534             :      *
     535             :      * Note that we stop splitting once we've done all needed for tupdesc
     536             :      */
     537          10 :     numpaths = 0;
     538          10 :     pos = xpathset;
     539          14 :     while (numpaths < (rsinfo->setDesc->natts - 1))
     540             :     {
     541          10 :         xpaths[numpaths++] = (xmlChar *) pos;
     542          10 :         pos = strstr(pos, pathsep);
     543          10 :         if (pos != NULL)
     544             :         {
     545           4 :             *pos = '\0';
     546           4 :             pos++;
     547             :         }
     548             :         else
     549           6 :             break;
     550             :     }
     551             : 
     552             :     /* Now build query */
     553          10 :     initStringInfo(&query_buf);
     554             : 
     555             :     /* Build initial sql statement */
     556          10 :     appendStringInfo(&query_buf, "SELECT %s, %s FROM %s WHERE %s",
     557             :                      pkeyfield,
     558             :                      xmlfield,
     559             :                      relname,
     560             :                      condition);
     561             : 
     562          10 :     SPI_connect();
     563             : 
     564          10 :     if ((ret = SPI_exec(query_buf.data, 0)) != SPI_OK_SELECT)
     565           0 :         elog(ERROR, "xpath_table: SPI execution failed for query %s",
     566             :              query_buf.data);
     567             : 
     568          10 :     proc = SPI_processed;
     569          10 :     tuptable = SPI_tuptable;
     570          10 :     spi_tupdesc = tuptable->tupdesc;
     571             : 
     572             :     /*
     573             :      * Check that SPI returned correct result. If you put a comma into one of
     574             :      * the function parameters, this will catch it when the SPI query returns
     575             :      * e.g. 3 columns.
     576             :      */
     577          10 :     if (spi_tupdesc->natts != 2)
     578             :     {
     579           0 :         ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
     580             :                         errmsg("expression returning multiple columns is not valid in parameter list"),
     581             :                         errdetail("Expected two columns in SPI result, got %d.", spi_tupdesc->natts)));
     582             :     }
     583             : 
     584             :     /*
     585             :      * Setup the parser.  This should happen after we are done evaluating the
     586             :      * query, in case it calls functions that set up libxml differently.
     587             :      */
     588          10 :     xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
     589             : 
     590          10 :     PG_TRY();
     591             :     {
     592             :         /* For each row i.e. document returned from SPI */
     593             :         uint64      i;
     594             : 
     595          20 :         for (i = 0; i < proc; i++)
     596             :         {
     597             :             char       *pkey;
     598             :             char       *xmldoc;
     599             :             xmlXPathContextPtr ctxt;
     600             :             xmlXPathObjectPtr res;
     601             :             xmlChar    *resstr;
     602             :             xmlXPathCompExprPtr comppath;
     603             :             HeapTuple   ret_tuple;
     604             : 
     605             :             /* Extract the row data as C Strings */
     606          10 :             spi_tuple = tuptable->vals[i];
     607          10 :             pkey = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
     608          10 :             xmldoc = SPI_getvalue(spi_tuple, spi_tupdesc, 2);
     609             : 
     610             :             /*
     611             :              * Clear the values array, so that not-well-formed documents
     612             :              * return NULL in all columns.  Note that this also means that
     613             :              * spare columns will be NULL.
     614             :              */
     615          30 :             for (j = 0; j < rsinfo->setDesc->natts; j++)
     616          20 :                 values[j] = NULL;
     617             : 
     618             :             /* Insert primary key */
     619          10 :             values[0] = pkey;
     620             : 
     621             :             /* Parse the document */
     622          10 :             if (xmldoc)
     623          10 :                 doctree = xmlReadMemory(xmldoc, strlen(xmldoc),
     624             :                                         NULL, NULL,
     625             :                                         XML_PARSE_NOENT);
     626             :             else                /* treat NULL as not well-formed */
     627           0 :                 doctree = NULL;
     628             : 
     629          10 :             if (doctree == NULL)
     630             :             {
     631             :                 /* not well-formed, so output all-NULL tuple */
     632           0 :                 ret_tuple = BuildTupleFromCStrings(attinmeta, values);
     633           0 :                 tuplestore_puttuple(rsinfo->setResult, ret_tuple);
     634           0 :                 heap_freetuple(ret_tuple);
     635             :             }
     636             :             else
     637             :             {
     638             :                 /* New loop here - we have to deal with nodeset results */
     639          10 :                 rownr = 0;
     640             : 
     641             :                 do
     642             :                 {
     643             :                     /* Now evaluate the set of xpaths. */
     644          16 :                     had_values = false;
     645          36 :                     for (j = 0; j < numpaths; j++)
     646             :                     {
     647          20 :                         ctxt = xmlXPathNewContext(doctree);
     648          20 :                         ctxt->node = xmlDocGetRootElement(doctree);
     649             : 
     650             :                         /* compile the path */
     651          20 :                         comppath = xmlXPathCtxtCompile(ctxt, xpaths[j]);
     652          20 :                         if (comppath == NULL)
     653           0 :                             xml_ereport(xmlerrcxt, ERROR,
     654             :                                         ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
     655             :                                         "XPath Syntax Error");
     656             : 
     657             :                         /* Now evaluate the path expression. */
     658          20 :                         res = xmlXPathCompiledEval(comppath, ctxt);
     659          20 :                         xmlXPathFreeCompExpr(comppath);
     660             : 
     661          20 :                         if (res != NULL)
     662             :                         {
     663          20 :                             switch (res->type)
     664             :                             {
     665          20 :                                 case XPATH_NODESET:
     666             :                                     /* We see if this nodeset has enough nodes */
     667          20 :                                     if (res->nodesetval != NULL &&
     668          20 :                                         rownr < res->nodesetval->nodeNr)
     669             :                                     {
     670           8 :                                         resstr = xmlXPathCastNodeToString(res->nodesetval->nodeTab[rownr]);
     671           8 :                                         had_values = true;
     672             :                                     }
     673             :                                     else
     674          12 :                                         resstr = NULL;
     675             : 
     676          20 :                                     break;
     677             : 
     678           0 :                                 case XPATH_STRING:
     679           0 :                                     resstr = xmlStrdup(res->stringval);
     680           0 :                                     break;
     681             : 
     682           0 :                                 default:
     683           0 :                                     elog(NOTICE, "unsupported XQuery result: %d", res->type);
     684           0 :                                     resstr = xmlStrdup((const xmlChar *) "<unsupported/>");
     685             :                             }
     686             : 
     687             :                             /*
     688             :                              * Insert this into the appropriate column in the
     689             :                              * result tuple.
     690             :                              */
     691          20 :                             values[j + 1] = (char *) resstr;
     692             :                         }
     693          20 :                         xmlXPathFreeContext(ctxt);
     694             :                     }
     695             : 
     696             :                     /* Now add the tuple to the output, if there is one. */
     697          16 :                     if (had_values)
     698             :                     {
     699           6 :                         ret_tuple = BuildTupleFromCStrings(attinmeta, values);
     700           6 :                         tuplestore_puttuple(rsinfo->setResult, ret_tuple);
     701           6 :                         heap_freetuple(ret_tuple);
     702             :                     }
     703             : 
     704          16 :                     rownr++;
     705          16 :                 } while (had_values);
     706             :             }
     707             : 
     708          10 :             if (doctree != NULL)
     709          10 :                 xmlFreeDoc(doctree);
     710          10 :             doctree = NULL;
     711             : 
     712          10 :             if (pkey)
     713          10 :                 pfree(pkey);
     714          10 :             if (xmldoc)
     715          10 :                 pfree(xmldoc);
     716             :         }
     717             :     }
     718           0 :     PG_CATCH();
     719             :     {
     720           0 :         if (doctree != NULL)
     721           0 :             xmlFreeDoc(doctree);
     722             : 
     723           0 :         pg_xml_done(xmlerrcxt, true);
     724             : 
     725           0 :         PG_RE_THROW();
     726             :     }
     727          10 :     PG_END_TRY();
     728             : 
     729          10 :     if (doctree != NULL)
     730           0 :         xmlFreeDoc(doctree);
     731             : 
     732          10 :     pg_xml_done(xmlerrcxt, false);
     733             : 
     734          10 :     SPI_finish();
     735             : 
     736             :     /*
     737             :      * SFRM_Materialize mode expects us to return a NULL Datum. The actual
     738             :      * tuples are in our tuplestore and passed back through rsinfo->setResult.
     739             :      * rsinfo->setDesc is set to the tuple description that we actually used
     740             :      * to build our tuples with, so the caller can verify we did what it was
     741             :      * expecting.
     742             :      */
     743          10 :     return (Datum) 0;
     744             : }

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