Add 0.2 version XML files.

contrib/xml/pgxml_dom.c

+/* Parser interface for DOM-based parser (libxml) rather than
+   stream-based SAX-type parser */
+
+#include "postgres.h"
+#include "fmgr.h"
+
+/* libxml includes */
+
+#include <libxml/xpath.h>
+#include <libxml/tree.h>
+#include <libxml/xmlmemory.h>
+
+/* 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_parser_init();
+
+static xmlChar *pgxmlNodeSetToText(xmlNodeSetPtr nodeset, xmlDocPtr doc, 
+				   xmlChar *toptagname, xmlChar *septagname, 
+				   int format);
+
+static xmlChar *pgxml_texttoxmlchar(text *textstring);
+
+
+Datum pgxml_parse(PG_FUNCTION_ARGS);
+Datum pgxml_xpath(PG_FUNCTION_ARGS);
+
+/* memory handling passthrough functions (e.g. palloc, pstrdup are
+   currently macros, and the others might become so...) */
+
+static void *pgxml_palloc(size_t size) 
+{
+  return palloc(size);
+}
+
+static void *pgxml_repalloc(void *ptr, size_t size)
+{
+  return repalloc(ptr,size);
+}
+
+static void pgxml_pfree(void *ptr)
+{
+  return pfree(ptr);
+}
+
+static char *pgxml_pstrdup(const char *string)
+{
+  return pstrdup(string);
+}
+
+static void pgxml_parser_init()
+{
+  /* This code should 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();
+
+}
+
+
+/* Returns true if document is well-formed */
+
+PG_FUNCTION_INFO_V1(pgxml_parse);
+
+Datum
+pgxml_parse(PG_FUNCTION_ARGS)
+{
+  /* called as pgxml_parse(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);  
+}
+
+static xmlChar 
+*pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
+		    xmlDocPtr doc,
+		    xmlChar *toptagname,
+		    xmlChar *septagname,
+		    int format)
+{
+  /* 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> */
+  /* if format==0, add a newline between nodes?? */
+
+  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 ((septagname != NULL) && (xmlStrlen(septagname)>0)) {
+	xmlBufferWriteChar(buf,"<");
+	xmlBufferWriteCHAR(buf,septagname);
+	xmlBufferWriteChar(buf,">");
+      }
+      xmlNodeDump(buf, doc, nodeset->nodeTab[i],1,(format==2));
+      
+      if ((septagname != NULL) && (xmlStrlen(septagname)>0)) {
+	xmlBufferWriteChar(buf,"</");
+	xmlBufferWriteCHAR(buf,septagname);
+	xmlBufferWriteChar(buf,">");
+      }
+      if (format) {
+	xmlBufferWriteChar(buf,"\n");
+      }
+    }
+  }
+
+  if ((toptagname != NULL) && (xmlStrlen(toptagname)>0)) {
+    xmlBufferWriteChar(buf,"</");
+    xmlBufferWriteCHAR(buf,toptagname);
+    xmlBufferWriteChar(buf,">");
+  }
+  result = xmlStrdup(buf->content);
+  xmlBufferFree(buf);
+  return result;
+}
+
+static 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;
+}
+
+
+PG_FUNCTION_INFO_V1(pgxml_xpath);
+
+Datum
+pgxml_xpath(PG_FUNCTION_ARGS)
+{
+  xmlDocPtr doctree;
+  xmlXPathContextPtr ctxt;
+  xmlXPathObjectPtr res;
+  xmlChar *xpath, *xpresstr, *toptag, *septag;
+  xmlXPathCompExprPtr comppath;
+
+  int32 docsize,ressize;
+  text *t, *xpres;
+
+  t = PG_GETARG_TEXT_P(0); /*document buffer */
+  xpath  = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(1)); /* XPath expression */
+  toptag = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(2));
+  septag = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(3));
+  
+  docsize = VARSIZE(t) - VARHDRSZ;
+
+  pgxml_parser_init();
+
+  doctree = xmlParseMemory((char *) VARDATA(t), docsize);
+  if (doctree == NULL) { /* not well-formed */
+    PG_RETURN_NULL();
+  }
+
+  ctxt = xmlXPathNewContext(doctree);
+  ctxt->node = xmlDocGetRootElement(doctree);
+
+  /* compile the path */
+  comppath = xmlXPathCompile(xpath);
+  if (comppath == NULL) {
+    elog(NOTICE, "XPath syntax error");
+    xmlFreeDoc(doctree);
+    pfree((void *) xpath);
+    PG_RETURN_NULL();
+  }
+
+  /* Now evaluate the path expression. */
+  res = xmlXPathCompiledEval(comppath,ctxt);
+  xmlXPathFreeCompExpr(comppath);
+
+  if (res==NULL) {
+    xmlFreeDoc(doctree);
+    pfree((void *)xpath);
+    PG_RETURN_NULL();   /* seems appropriate */
+  }
+  /* now we dump this node, ?surrounding by tags? */
+  /* To do this, we look first at the type */
+  switch(res->type) {
+  case XPATH_NODESET: 
+    xpresstr = pgxmlNodeSetToText(res->nodesetval,
+				  doctree,
+				  toptag, septag, 0);
+    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);
+  VARATT_SIZEP(xpres)=ressize + VARHDRSZ;
+
+  /* Free various storage */
+  xmlFreeDoc(doctree);
+  pfree((void *) xpath);
+  xmlFree(xpresstr);
+
+  PG_RETURN_TEXT_P(xpres);
+}
+
+
+
+

contrib/xml/pgxml_dom.source

+--SQL for XML parser
+
+CREATE FUNCTION pgxml_parse(text) RETURNS bool
+	AS '_OBJWD_/pgxml_dom_DLSUFFIX_' LANGUAGE 'c' WITH (isStrict);
+
+CREATE FUNCTION pgxml_xpath(text,text,text,text) RETURNS text
+	AS '_OBJWD_/pgxml_dom_DLSUFFIX_' LANGUAGE 'c' WITH (isStrict);
\ No newline at end of file