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Commit 4859219

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bmomjianbmomjian
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Add 0.2 version XML files.
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‎contrib/xml/pgxml_dom.c

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/* Parser interface for DOM-based parser (libxml) rather than
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stream-based SAX-type parser */
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#include "postgres.h"
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#include "fmgr.h"
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/* libxml includes */
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#include <libxml/xpath.h>
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#include <libxml/tree.h>
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#include <libxml/xmlmemory.h>
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/* declarations */
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static void *pgxml_palloc(size_t size);
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static void *pgxml_repalloc(void *ptr, size_t size);
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static void pgxml_pfree(void *ptr);
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static char *pgxml_pstrdup(const char* string);
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static void pgxml_parser_init();
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static xmlChar *pgxmlNodeSetToText(xmlNodeSetPtr nodeset, xmlDocPtr doc,
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xmlChar *toptagname, xmlChar *septagname,
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int format);
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static xmlChar *pgxml_texttoxmlchar(text *textstring);
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Datum pgxml_parse(PG_FUNCTION_ARGS);
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Datum pgxml_xpath(PG_FUNCTION_ARGS);
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/* memory handling passthrough functions (e.g. palloc, pstrdup are
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currently macros, and the others might become so...) */
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static void *pgxml_palloc(size_t size)
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{
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return palloc(size);
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}
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static void *pgxml_repalloc(void *ptr, size_t size)
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{
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return repalloc(ptr,size);
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}
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static void pgxml_pfree(void *ptr)
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{
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return pfree(ptr);
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}
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static char *pgxml_pstrdup(const char *string)
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{
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return pstrdup(string);
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}
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static void pgxml_parser_init()
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{
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/* This code should also set parser settings from user-supplied
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info. Quite how these settings are made is another matter :) */
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xmlMemSetup(pgxml_pfree, pgxml_palloc, pgxml_repalloc, pgxml_pstrdup);
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xmlInitParser();
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}
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/* Returns true if document is well-formed */
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PG_FUNCTION_INFO_V1(pgxml_parse);
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Datum
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pgxml_parse(PG_FUNCTION_ARGS)
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{
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/* called as pgxml_parse(document) */
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xmlDocPtr doctree;
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text *t = PG_GETARG_TEXT_P(0); /*document buffer */
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int32 docsize = VARSIZE(t) - VARHDRSZ;
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pgxml_parser_init();
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doctree = xmlParseMemory((char *) VARDATA(t), docsize);
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if (doctree == NULL) {
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/* xmlCleanupParser(); */
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PG_RETURN_BOOL(false); /* i.e. not well-formed */
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}
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/* xmlCleanupParser(); */
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xmlFreeDoc(doctree);
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PG_RETURN_BOOL(true);
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}
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static xmlChar
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*pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
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xmlDocPtr doc,
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xmlChar *toptagname,
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xmlChar *septagname,
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int format)
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{
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/* Function translates a nodeset into a text representation */
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/* iterates over each node in the set and calls xmlNodeDump to write
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it to an xmlBuffer -from which an xmlChar * string is returned. */
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/* each representation is surrounded by <tagname> ... </tagname> */
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/* if format==0, add a newline between nodes?? */
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xmlBufferPtr buf;
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xmlChar *result;
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int i;
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buf =xmlBufferCreate();
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if ((toptagname != NULL) && (xmlStrlen(toptagname)>0)) {
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xmlBufferWriteChar(buf,"<");
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xmlBufferWriteCHAR(buf,toptagname);
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xmlBufferWriteChar(buf,">");
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}
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if (nodeset != NULL) {
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for (i=0; i < nodeset->nodeNr; i++) {
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if ((septagname != NULL) && (xmlStrlen(septagname)>0)) {
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xmlBufferWriteChar(buf,"<");
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xmlBufferWriteCHAR(buf,septagname);
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xmlBufferWriteChar(buf,">");
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}
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xmlNodeDump(buf, doc, nodeset->nodeTab[i],1,(format==2));
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if ((septagname != NULL) && (xmlStrlen(septagname)>0)) {
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xmlBufferWriteChar(buf,"</");
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xmlBufferWriteCHAR(buf,septagname);
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xmlBufferWriteChar(buf,">");
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}
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if (format) {
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xmlBufferWriteChar(buf,"\n");
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}
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}
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}
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if ((toptagname != NULL) && (xmlStrlen(toptagname)>0)) {
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xmlBufferWriteChar(buf,"</");
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xmlBufferWriteCHAR(buf,toptagname);
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xmlBufferWriteChar(buf,">");
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}
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result = xmlStrdup(buf->content);
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xmlBufferFree(buf);
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return result;
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}
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static xmlChar *pgxml_texttoxmlchar(text *textstring) {
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xmlChar *res;
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int32 txsize;
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txsize=VARSIZE(textstring)-VARHDRSZ;
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res = (xmlChar *) palloc(txsize+1);
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memcpy((char *)res, VARDATA(textstring), txsize);
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res[txsize]='\0';
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return res;
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}
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PG_FUNCTION_INFO_V1(pgxml_xpath);
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Datum
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pgxml_xpath(PG_FUNCTION_ARGS)
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{
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xmlDocPtr doctree;
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xmlXPathContextPtr ctxt;
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xmlXPathObjectPtr res;
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xmlChar *xpath, *xpresstr, *toptag, *septag;
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xmlXPathCompExprPtr comppath;
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int32 docsize,ressize;
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text *t, *xpres;
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t = PG_GETARG_TEXT_P(0); /*document buffer */
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xpath = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(1)); /* XPath expression */
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toptag = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(2));
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septag = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(3));
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docsize = VARSIZE(t) - VARHDRSZ;
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pgxml_parser_init();
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doctree = xmlParseMemory((char *) VARDATA(t), docsize);
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if (doctree == NULL) { /* not well-formed */
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PG_RETURN_NULL();
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}
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ctxt = xmlXPathNewContext(doctree);
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ctxt->node = xmlDocGetRootElement(doctree);
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/* compile the path */
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comppath = xmlXPathCompile(xpath);
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if (comppath == NULL) {
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elog(NOTICE, "XPath syntax error");
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xmlFreeDoc(doctree);
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pfree((void *) xpath);
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PG_RETURN_NULL();
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}
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/* Now evaluate the path expression. */
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res = xmlXPathCompiledEval(comppath,ctxt);
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xmlXPathFreeCompExpr(comppath);
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if (res==NULL) {
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xmlFreeDoc(doctree);
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pfree((void *)xpath);
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PG_RETURN_NULL(); /* seems appropriate */
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}
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/* now we dump this node, ?surrounding by tags? */
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/* To do this, we look first at the type */
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switch(res->type) {
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case XPATH_NODESET:
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xpresstr = pgxmlNodeSetToText(res->nodesetval,
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doctree,
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toptag, septag, 0);
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break;
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case XPATH_STRING:
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xpresstr = xmlStrdup(res->stringval);
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break;
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default:
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elog(NOTICE,"Unsupported XQuery result: %d",res->type);
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xpresstr = xmlStrdup("<unsupported/>");
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}
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/* Now convert this result back to text */
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ressize = strlen(xpresstr);
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xpres = (text *) palloc(ressize+VARHDRSZ);
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memcpy(VARDATA(xpres),xpresstr,ressize);
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VARATT_SIZEP(xpres)=ressize + VARHDRSZ;
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/* Free various storage */
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xmlFreeDoc(doctree);
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pfree((void *) xpath);
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xmlFree(xpresstr);
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PG_RETURN_TEXT_P(xpres);
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}
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‎contrib/xml/pgxml_dom.source

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--SQL for XML parser
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CREATE FUNCTION pgxml_parse(text) RETURNS bool
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AS '_OBJWD_/pgxml_dom_DLSUFFIX_' LANGUAGE 'c' WITH (isStrict);
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CREATE FUNCTION pgxml_xpath(text,text,text,text) RETURNS text
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AS '_OBJWD_/pgxml_dom_DLSUFFIX_' LANGUAGE 'c' WITH (isStrict);

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