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postgresql/contrib/xml2/xpath.c
Tom Lane 234a02b2a8 Replace direct assignments to VARATT_SIZEP(x) with SET_VARSIZE(x, len). 
Get rid of VARATT_SIZE and VARATT_DATA, which were simply redundant with
VARSIZE and VARDATA, and as a consequence almost no code was using the
longer names.  Rename the length fields of struct varlena and various
derived structures to catch anyplace that was accessing them directly;
and clean up various places so caught.  In itself this patch doesn't
change any behavior at all, but it is necessary infrastructure if we hope
to play any games with the representation of varlena headers.
Greg Stark and Tom Lane
2007-02-27 23:48:10 +00:00

948 lines
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/* Parser interface for DOM-based parser (libxml) rather than
stream-based SAX-type parser */
#include "postgres.h"
#include "fmgr.h"
#include "executor/spi.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "lib/stringinfo.h"
/* libxml includes */
#include <libxml/xpath.h>
#include <libxml/tree.h>
#include <libxml/xmlmemory.h>
#include <libxml/xmlerror.h>
#include <libxml/parserInternals.h>
PG_MODULE_MAGIC;
/* declarations */
static void *pgxml_palloc(size_t size);
static void *pgxml_repalloc(void *ptr, size_t size);
static void pgxml_pfree(void *ptr);
static char *pgxml_pstrdup(const char *string);
static void pgxml_errorHandler(void *ctxt, const char *msg,...);
void elog_error(int level, char *explain, int force);
void pgxml_parser_init(void);
static xmlChar *pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
xmlChar * toptagname, xmlChar * septagname,
xmlChar * plainsep);
text *pgxml_result_to_text(xmlXPathObjectPtr res, xmlChar * toptag,
xmlChar * septag, xmlChar * plainsep);
xmlChar *pgxml_texttoxmlchar(text *textstring);
static xmlXPathObjectPtr pgxml_xpath(text *document, xmlChar * xpath);
Datum xml_is_well_formed(PG_FUNCTION_ARGS);
Datum xml_encode_special_chars(PG_FUNCTION_ARGS);
Datum xpath_nodeset(PG_FUNCTION_ARGS);
Datum xpath_string(PG_FUNCTION_ARGS);
Datum xpath_number(PG_FUNCTION_ARGS);
Datum xpath_bool(PG_FUNCTION_ARGS);
Datum xpath_list(PG_FUNCTION_ARGS);
Datum xpath_table(PG_FUNCTION_ARGS);
/* Global variables */
char *errbuf; /* per line error buffer */
char *pgxml_errorMsg = NULL; /* overall error message */
/* Convenience macros */
#define GET_TEXT(cstrp) DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(cstrp)))
#define GET_STR(textp) DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(textp)))
#define ERRBUF_SIZE 200
/* memory handling passthrough functions (e.g. palloc, pstrdup are
currently macros, and the others might become so...) */
static void *
pgxml_palloc(size_t size)
{
/* elog(DEBUG1,"Alloc %d in CMC %p",size,CurrentMemoryContext); */
return palloc(size);
}
static void *
pgxml_repalloc(void *ptr, size_t size)
{
/* elog(DEBUG1,"ReAlloc in CMC %p",CurrentMemoryContext);*/
return repalloc(ptr, size);
}
static void
pgxml_pfree(void *ptr)
{
/* elog(DEBUG1,"Free in CMC %p",CurrentMemoryContext); */
pfree(ptr);
}
static char *
pgxml_pstrdup(const char *string)
{
return pstrdup(string);
}
/* The error handling function. This formats an error message and sets
* a flag - an ereport will be issued prior to return
*/
static void
pgxml_errorHandler(void *ctxt, const char *msg,...)
{
va_list args;
va_start(args, msg);
vsnprintf(errbuf, ERRBUF_SIZE, msg, args);
va_end(args);
/* Now copy the argument across */
if (pgxml_errorMsg == NULL)
pgxml_errorMsg = pstrdup(errbuf);
else
{
int32 xsize = strlen(pgxml_errorMsg);
pgxml_errorMsg = repalloc(pgxml_errorMsg,
(size_t) (xsize + strlen(errbuf) + 1));
strncpy(&pgxml_errorMsg[xsize - 1], errbuf, strlen(errbuf));
pgxml_errorMsg[xsize + strlen(errbuf) - 1] = '\0';
}
memset(errbuf, 0, ERRBUF_SIZE);
}
/* This function reports the current message at the level specified */
void
elog_error(int level, char *explain, int force)
{
if (force || (pgxml_errorMsg != NULL))
{
if (pgxml_errorMsg == NULL)
{
ereport(level, (errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
errmsg(explain)));
}
else
{
ereport(level, (errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
errmsg("%s:%s", explain, pgxml_errorMsg)));
pfree(pgxml_errorMsg);
}
}
}
void
pgxml_parser_init()
{
/*
* This code could also set parser settings from user-supplied info.
* Quite how these settings are made is another matter :)
*/
xmlMemSetup(pgxml_pfree, pgxml_palloc, pgxml_repalloc, pgxml_pstrdup);
xmlInitParser();
xmlSetGenericErrorFunc(NULL, pgxml_errorHandler);
xmlSubstituteEntitiesDefault(1);
xmlLoadExtDtdDefaultValue = 1;
pgxml_errorMsg = NULL;
errbuf = palloc(200);
memset(errbuf, 0, 200);
}
/* Returns true if document is well-formed */
PG_FUNCTION_INFO_V1(xml_is_well_formed);
Datum
xml_is_well_formed(PG_FUNCTION_ARGS)
{
/* called as xml_is_well_formed(document) */
xmlDocPtr doctree;
text *t = PG_GETARG_TEXT_P(0); /* document buffer */
int32 docsize = VARSIZE(t) - VARHDRSZ;
pgxml_parser_init();
doctree = xmlParseMemory((char *) VARDATA(t), docsize);
if (doctree == NULL)
{
xmlCleanupParser();
PG_RETURN_BOOL(false); /* i.e. not well-formed */
}
xmlCleanupParser();
xmlFreeDoc(doctree);
PG_RETURN_BOOL(true);
}
/* Encodes special characters (<, >, &, " and \r) as XML entities */
PG_FUNCTION_INFO_V1(xml_encode_special_chars);
Datum
xml_encode_special_chars(PG_FUNCTION_ARGS)
{
text *tin = PG_GETARG_TEXT_P(0);
text *tout;
int32 ressize;
xmlChar *ts,
*tt;
ts = pgxml_texttoxmlchar(tin);
tt = xmlEncodeSpecialChars(NULL, ts);
pfree(ts);
ressize = strlen(tt);
tout = (text *) palloc(ressize + VARHDRSZ);
memcpy(VARDATA(tout), tt, ressize);
SET_VARSIZE(tout, ressize + VARHDRSZ);
xmlFree(tt);
PG_RETURN_TEXT_P(tout);
}
static xmlChar
*
pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
xmlChar * toptagname,
xmlChar * septagname,
xmlChar * plainsep)
{
/* Function translates a nodeset into a text representation */
/*
* iterates over each node in the set and calls xmlNodeDump to write it to
* an xmlBuffer -from which an xmlChar * string is returned.
*/
/* each representation is surrounded by <tagname> ... </tagname> */
/*
* plainsep is an ordinary (not tag) seperator - if used, then nodes are
* cast to string as output method
*/
xmlBufferPtr buf;
xmlChar *result;
int i;
buf = xmlBufferCreate();
if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
{
xmlBufferWriteChar(buf, "<");
xmlBufferWriteCHAR(buf, toptagname);
xmlBufferWriteChar(buf, ">");
}
if (nodeset != NULL)
{
for (i = 0; i < nodeset->nodeNr; i++)
{
if (plainsep != NULL)
{
xmlBufferWriteCHAR(buf,
xmlXPathCastNodeToString(nodeset->nodeTab[i]));
/* If this isn't the last entry, write the plain sep. */
if (i < (nodeset->nodeNr) - 1)
xmlBufferWriteChar(buf, plainsep);
}
else
{
if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
{
xmlBufferWriteChar(buf, "<");
xmlBufferWriteCHAR(buf, septagname);
xmlBufferWriteChar(buf, ">");
}
xmlNodeDump(buf,
nodeset->nodeTab[i]->doc,
nodeset->nodeTab[i],
1, 0);
if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
{
xmlBufferWriteChar(buf, "</");
xmlBufferWriteCHAR(buf, septagname);
xmlBufferWriteChar(buf, ">");
}
}
}
}
if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
{
xmlBufferWriteChar(buf, "</");
xmlBufferWriteCHAR(buf, toptagname);
xmlBufferWriteChar(buf, ">");
}
result = xmlStrdup(buf->content);
xmlBufferFree(buf);
return result;
}
/* Translate a PostgreSQL "varlena" -i.e. a variable length parameter
* into the libxml2 representation
*/
xmlChar *
pgxml_texttoxmlchar(text *textstring)
{
xmlChar *res;
int32 txsize;
txsize = VARSIZE(textstring) - VARHDRSZ;
res = (xmlChar *) palloc(txsize + 1);
memcpy((char *) res, VARDATA(textstring), txsize);
res[txsize] = '\0';
return res;
}
/* Public visible XPath functions */
/* This is a "raw" xpath function. Check that it returns child elements
* properly
*/
PG_FUNCTION_INFO_V1(xpath_nodeset);
Datum
xpath_nodeset(PG_FUNCTION_ARGS)
{
xmlChar *xpath,
*toptag,
*septag;
int32 pathsize;
text
*xpathsupp,
*xpres;
/* PG_GETARG_TEXT_P(0) is document buffer */
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
toptag = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(2));
septag = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(3));
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
xpath = pgxml_texttoxmlchar(xpathsupp);
xpres = pgxml_result_to_text(
pgxml_xpath(PG_GETARG_TEXT_P(0), xpath),
toptag, septag, NULL);
/* xmlCleanupParser(); done by result_to_text routine */
pfree(xpath);
if (xpres == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(xpres);
}
/* The following function is almost identical, but returns the elements in */
/* a list. */
PG_FUNCTION_INFO_V1(xpath_list);
Datum
xpath_list(PG_FUNCTION_ARGS)
{
xmlChar *xpath,
*plainsep;
int32 pathsize;
text
*xpathsupp,
*xpres;
/* PG_GETARG_TEXT_P(0) is document buffer */
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
plainsep = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(2));
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
xpath = pgxml_texttoxmlchar(xpathsupp);
xpres = pgxml_result_to_text(
pgxml_xpath(PG_GETARG_TEXT_P(0), xpath),
NULL, NULL, plainsep);
/* xmlCleanupParser(); done by result_to_text routine */
pfree(xpath);
if (xpres == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(xpres);
}
PG_FUNCTION_INFO_V1(xpath_string);
Datum
xpath_string(PG_FUNCTION_ARGS)
{
xmlChar *xpath;
int32 pathsize;
text
*xpathsupp,
*xpres;
/* PG_GETARG_TEXT_P(0) is document buffer */
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
/*
* We encapsulate the supplied path with "string()" = 8 chars + 1 for NUL
* at end
*/
/* We could try casting to string using the libxml function? */
xpath = (xmlChar *) palloc(pathsize + 9);
memcpy((char *) (xpath + 7), VARDATA(xpathsupp), pathsize);
strncpy((char *) xpath, "string(", 7);
xpath[pathsize + 7] = ')';
xpath[pathsize + 8] = '\0';
xpres = pgxml_result_to_text(
pgxml_xpath(PG_GETARG_TEXT_P(0), xpath),
NULL, NULL, NULL);
xmlCleanupParser();
pfree(xpath);
if (xpres == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(xpres);
}
PG_FUNCTION_INFO_V1(xpath_number);
Datum
xpath_number(PG_FUNCTION_ARGS)
{
xmlChar *xpath;
int32 pathsize;
text
*xpathsupp;
float4 fRes;
xmlXPathObjectPtr res;
/* PG_GETARG_TEXT_P(0) is document buffer */
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
xpath = pgxml_texttoxmlchar(xpathsupp);
res = pgxml_xpath(PG_GETARG_TEXT_P(0), xpath);
pfree(xpath);
if (res == NULL)
{
xmlCleanupParser();
PG_RETURN_NULL();
}
fRes = xmlXPathCastToNumber(res);
xmlCleanupParser();
if (xmlXPathIsNaN(fRes))
PG_RETURN_NULL();
PG_RETURN_FLOAT4(fRes);
}
PG_FUNCTION_INFO_V1(xpath_bool);
Datum
xpath_bool(PG_FUNCTION_ARGS)
{
xmlChar *xpath;
int32 pathsize;
text
*xpathsupp;
int bRes;
xmlXPathObjectPtr res;
/* PG_GETARG_TEXT_P(0) is document buffer */
xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
pathsize = VARSIZE(xpathsupp) - VARHDRSZ;
xpath = pgxml_texttoxmlchar(xpathsupp);
res = pgxml_xpath(PG_GETARG_TEXT_P(0), xpath);
pfree(xpath);
if (res == NULL)
{
xmlCleanupParser();
PG_RETURN_BOOL(false);
}
bRes = xmlXPathCastToBoolean(res);
xmlCleanupParser();
PG_RETURN_BOOL(bRes);
}
/* Core function to evaluate XPath query */
xmlXPathObjectPtr
pgxml_xpath(text *document, xmlChar * xpath)
{
xmlDocPtr doctree;
xmlXPathContextPtr ctxt;
xmlXPathObjectPtr res;
xmlXPathCompExprPtr comppath;
int32 docsize;
docsize = VARSIZE(document) - VARHDRSZ;
pgxml_parser_init();
doctree = xmlParseMemory((char *) VARDATA(document), docsize);
if (doctree == NULL)
{ /* not well-formed */
return NULL;
}
ctxt = xmlXPathNewContext(doctree);
ctxt->node = xmlDocGetRootElement(doctree);
/* compile the path */
comppath = xmlXPathCompile(xpath);
if (comppath == NULL)
{
xmlCleanupParser();
xmlFreeDoc(doctree);
elog_error(ERROR, "XPath Syntax Error", 1);
return NULL;
}
/* Now evaluate the path expression. */
res = xmlXPathCompiledEval(comppath, ctxt);
xmlXPathFreeCompExpr(comppath);
if (res == NULL)
{
xmlXPathFreeContext(ctxt);
/* xmlCleanupParser(); */
xmlFreeDoc(doctree);
return NULL;
}
/* xmlFreeDoc(doctree); */
return res;
}
text
*
pgxml_result_to_text(xmlXPathObjectPtr res,
xmlChar * toptag,
xmlChar * septag,
xmlChar * plainsep)
{
xmlChar *xpresstr;
int32 ressize;
text *xpres;
if (res == NULL)
{
xmlCleanupParser();
return NULL;
}
switch (res->type)
{
case XPATH_NODESET:
xpresstr = pgxmlNodeSetToText(res->nodesetval,
toptag,
septag, plainsep);
break;
case XPATH_STRING:
xpresstr = xmlStrdup(res->stringval);
break;
default:
elog(NOTICE, "unsupported XQuery result: %d", res->type);
xpresstr = xmlStrdup("<unsupported/>");
}
/* Now convert this result back to text */
ressize = strlen(xpresstr);
xpres = (text *) palloc(ressize + VARHDRSZ);
memcpy(VARDATA(xpres), xpresstr, ressize);
SET_VARSIZE(xpres, ressize + VARHDRSZ);
/* Free various storage */
xmlCleanupParser();
/* xmlFreeDoc(doctree); -- will die at end of tuple anyway */
xmlFree(xpresstr);
elog_error(ERROR, "XPath error", 0);
return xpres;
}
/* xpath_table is a table function. It needs some tidying (as do the
* other functions here!
*/
PG_FUNCTION_INFO_V1(xpath_table);
Datum
xpath_table(PG_FUNCTION_ARGS)
{
/* SPI (input tuple) support */
SPITupleTable *tuptable;
HeapTuple spi_tuple;
TupleDesc spi_tupdesc;
/* Output tuple (tuplestore) support */
Tuplestorestate *tupstore = NULL;
TupleDesc ret_tupdesc;
HeapTuple ret_tuple;
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
AttInMetadata *attinmeta;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
/* Function parameters */
char *pkeyfield = GET_STR(PG_GETARG_TEXT_P(0));
char *xmlfield = GET_STR(PG_GETARG_TEXT_P(1));
char *relname = GET_STR(PG_GETARG_TEXT_P(2));
char *xpathset = GET_STR(PG_GETARG_TEXT_P(3));
char *condition = GET_STR(PG_GETARG_TEXT_P(4));
char **values;
xmlChar **xpaths;
xmlChar *pos;
xmlChar *pathsep = "|";
int numpaths;
int ret;
int proc;
int i;
int j;
int rownr; /* For issuing multiple rows from one original
* document */
int had_values; /* To determine end of nodeset results */
StringInfoData query_buf;
/* We only have a valid tuple description in table function mode */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (rsinfo->expectedDesc == NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("xpath_table must be called as a table function")));
/*
* We want to materialise because it means that we don't have to carry
* libxml2 parser state between invocations of this function
*/
if (!(rsinfo->allowedModes & SFRM_Materialize))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("xpath_table requires Materialize mode, but it is not "
"allowed in this context")));
/*
* The tuplestore must exist in a higher context than this function call
* (per_query_ctx is used)
*/
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
/*
* Create the tuplestore - work_mem is the max in-memory size before a
* file is created on disk to hold it.
*/
tupstore = tuplestore_begin_heap(true, false, work_mem);
MemoryContextSwitchTo(oldcontext);
/* get the requested return tuple description */
ret_tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
/*
* At the moment we assume that the returned attributes make sense for the
* XPath specififed (i.e. we trust the caller). It's not fatal if they get
* it wrong - the input function for the column type will raise an error
* if the path result can't be converted into the correct binary
* representation.
*/
attinmeta = TupleDescGetAttInMetadata(ret_tupdesc);
/* Set return mode and allocate value space. */
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setDesc = ret_tupdesc;
values = (char **) palloc(ret_tupdesc->natts * sizeof(char *));
xpaths = (xmlChar **) palloc(ret_tupdesc->natts * sizeof(xmlChar *));
/* Split XPaths. xpathset is a writable CString. */
/* Note that we stop splitting once we've done all needed for tupdesc */
numpaths = 0;
pos = xpathset;
do
{
xpaths[numpaths] = pos;
pos = strstr(pos, pathsep);
if (pos != NULL)
{
*pos = '\0';
pos++;
}
numpaths++;
} while ((pos != NULL) && (numpaths < (ret_tupdesc->natts - 1)));
/* Now build query */
initStringInfo(&query_buf);
/* Build initial sql statement */
appendStringInfo(&query_buf, "SELECT %s, %s FROM %s WHERE %s",
pkeyfield,
xmlfield,
relname,
condition
);
if ((ret = SPI_connect()) < 0)
elog(ERROR, "xpath_table: SPI_connect returned %d", ret);
if ((ret = SPI_exec(query_buf.data, 0)) != SPI_OK_SELECT)
elog(ERROR, "xpath_table: SPI execution failed for query %s", query_buf.data);
proc = SPI_processed;
/* elog(DEBUG1,"xpath_table: SPI returned %d rows",proc); */
tuptable = SPI_tuptable;
spi_tupdesc = tuptable->tupdesc;
/* Switch out of SPI context */
MemoryContextSwitchTo(oldcontext);
/* Check that SPI returned correct result. If you put a comma into one of
* the function parameters, this will catch it when the SPI query returns
* e.g. 3 columns.
*/
if (spi_tupdesc->natts != 2)
{
ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("expression returning multiple columns is not valid in parameter list"),
errdetail("Expected two columns in SPI result, got %d.", spi_tupdesc->natts)));
}
/* Setup the parser. Beware that this must happen in the same context as the
* cleanup - which means that any error from here on must do cleanup to
* ensure that the entity table doesn't get freed by being out of context.
*/
pgxml_parser_init();
/* For each row i.e. document returned from SPI */
for (i = 0; i < proc; i++)
{
char *pkey;
char *xmldoc;
xmlDocPtr doctree;
xmlXPathContextPtr ctxt;
xmlXPathObjectPtr res;
xmlChar *resstr;
xmlXPathCompExprPtr comppath;
/* Extract the row data as C Strings */
spi_tuple = tuptable->vals[i];
pkey = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
xmldoc = SPI_getvalue(spi_tuple, spi_tupdesc, 2);
/*
* Clear the values array, so that not-well-formed documents return
* NULL in all columns.
*/
/* Note that this also means that spare columns will be NULL. */
for (j = 0; j < ret_tupdesc->natts; j++)
values[j] = NULL;
/* Insert primary key */
values[0] = pkey;
/* Parse the document */
doctree = xmlParseMemory(xmldoc, strlen(xmldoc));
if (doctree == NULL)
{ /* not well-formed, so output all-NULL tuple */
ret_tuple = BuildTupleFromCStrings(attinmeta, values);
oldcontext = MemoryContextSwitchTo(per_query_ctx);
tuplestore_puttuple(tupstore, ret_tuple);
MemoryContextSwitchTo(oldcontext);
heap_freetuple(ret_tuple);
}
else
{
/* New loop here - we have to deal with nodeset results */
rownr = 0;
do
{
/* Now evaluate the set of xpaths. */
had_values = 0;
for (j = 0; j < numpaths; j++)
{
ctxt = xmlXPathNewContext(doctree);
ctxt->node = xmlDocGetRootElement(doctree);
xmlSetGenericErrorFunc(ctxt, pgxml_errorHandler);
/* compile the path */
comppath = xmlXPathCompile(xpaths[j]);
if (comppath == NULL)
{
xmlCleanupParser();
xmlFreeDoc(doctree);
elog_error(ERROR, "XPath Syntax Error", 1);
PG_RETURN_NULL(); /* Keep compiler happy */
}
/* Now evaluate the path expression. */
res = xmlXPathCompiledEval(comppath, ctxt);
xmlXPathFreeCompExpr(comppath);
if (res != NULL)
{
switch (res->type)
{
case XPATH_NODESET:
/* We see if this nodeset has enough nodes */
if ((res->nodesetval != NULL) && (rownr < res->nodesetval->nodeNr))
{
resstr =
xmlXPathCastNodeToString(res->nodesetval->nodeTab[rownr]);
had_values = 1;
}
else
resstr = NULL;
break;
case XPATH_STRING:
resstr = xmlStrdup(res->stringval);
break;
default:
elog(NOTICE, "unsupported XQuery result: %d", res->type);
resstr = xmlStrdup("<unsupported/>");
}
/*
* Insert this into the appropriate column in the
* result tuple.
*/
values[j + 1] = resstr;
}
xmlXPathFreeContext(ctxt);
}
/* Now add the tuple to the output, if there is one. */
if (had_values)
{
ret_tuple = BuildTupleFromCStrings(attinmeta, values);
oldcontext = MemoryContextSwitchTo(per_query_ctx);
tuplestore_puttuple(tupstore, ret_tuple);
MemoryContextSwitchTo(oldcontext);
heap_freetuple(ret_tuple);
}
rownr++;
} while (had_values);
}
xmlFreeDoc(doctree);
pfree(pkey);
pfree(xmldoc);
}
xmlCleanupParser();
/* Needed to flag completeness in 7.3.1. 7.4 defines it as a no-op. */
tuplestore_donestoring(tupstore);
SPI_finish();
rsinfo->setResult = tupstore;
/*
* SFRM_Materialize mode expects us to return a NULL Datum. The actual
* tuples are in our tuplestore and passed back through rsinfo->setResult.
* rsinfo->setDesc is set to the tuple description that we actually used
* to build our tuples with, so the caller can verify we did what it was
* expecting.
*/
return (Datum) 0;
}
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