static xmlXPathObjectPtr
pgxml_xpath(text *document, xmlChar *xpath, xpath_workspace *workspace)
{
int32 docsize = VARSIZE(document) - VARHDRSZ;
PgXmlErrorContext *xmlerrcxt;
xmlXPathCompExprPtr comppath;
workspace->doctree = NULL;
workspace->ctxt = NULL;
workspace->res = NULL;
xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
PG_TRY();
{
workspace->doctree = xmlParseMemory((char *) VARDATA(document),
docsize);
if (workspace->doctree != NULL)
{
workspace->ctxt = xmlXPathNewContext(workspace->doctree);
workspace->ctxt->node = xmlDocGetRootElement(workspace->doctree);
/* compile the path */
comppath = xmlXPathCompile(xpath);
if (comppath == NULL)
xml_ereport(xmlerrcxt, ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
"XPath Syntax Error");
/* Now evaluate the path expression. */
workspace->res = xmlXPathCompiledEval(comppath, workspace->ctxt);
xmlXPathFreeCompExpr(comppath);
}
}
PG_CATCH();
{
cleanup_workspace(workspace);
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
PG_END_TRY();
if (workspace->res == NULL)
cleanup_workspace(workspace);
pg_xml_done(xmlerrcxt, false);
return workspace->res;
}
Datum
xpath_bool(PG_FUNCTION_ARGS)
{
text *document = PG_GETARG_TEXT_P(0);
text *xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
xmlChar *xpath;
int bRes;
xmlXPathObjectPtr res;
xpath_workspace workspace;
xpath = pgxml_texttoxmlchar(xpathsupp);
res = pgxml_xpath(document, xpath, &workspace);
pfree(xpath);
if (res == NULL)
PG_RETURN_BOOL(false);
bRes = xmlXPathCastToBoolean(res);
cleanup_workspace(&workspace);
PG_RETURN_BOOL(bRes);
}
Datum
xpath_number(PG_FUNCTION_ARGS)
{
text *document = PG_GETARG_TEXT_P(0);
text *xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
xmlChar *xpath;
float4 fRes;
xmlXPathObjectPtr res;
xpath_workspace workspace;
xpath = pgxml_texttoxmlchar(xpathsupp);
res = pgxml_xpath(document, xpath, &workspace);
pfree(xpath);
if (res == NULL)
PG_RETURN_NULL();
fRes = xmlXPathCastToNumber(res);
cleanup_workspace(&workspace);
if (xmlXPathIsNaN(fRes))
PG_RETURN_NULL();
PG_RETURN_FLOAT4(fRes);
}
Datum
xpath_list(PG_FUNCTION_ARGS)
{
text *document = PG_GETARG_TEXT_P(0);
text *xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
xmlChar *plainsep = pgxml_texttoxmlchar(PG_GETARG_TEXT_P(2));
xmlChar *xpath;
text *xpres;
xmlXPathObjectPtr res;
xpath_workspace workspace;
xpath = pgxml_texttoxmlchar(xpathsupp);
res = pgxml_xpath(document, xpath, &workspace);
xpres = pgxml_result_to_text(res, NULL, NULL, plainsep);
cleanup_workspace(&workspace);
pfree(xpath);
if (xpres == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(xpres);
}
static xmlXPathObjectPtr
pgxml_xpath(text *document, xmlChar *xpath, xpath_workspace *workspace)
{
int32 docsize = VARSIZE(document) - VARHDRSZ;
xmlXPathObjectPtr res;
xmlXPathCompExprPtr comppath;
workspace->doctree = NULL;
workspace->ctxt = NULL;
workspace->res = NULL;
pgxml_parser_init();
workspace->doctree = xmlParseMemory((char *) VARDATA(document), docsize);
if (workspace->doctree == NULL)
return NULL; /* not well-formed */
workspace->ctxt = xmlXPathNewContext(workspace->doctree);
workspace->ctxt->node = xmlDocGetRootElement(workspace->doctree);
/* compile the path */
comppath = xmlXPathCompile(xpath);
if (comppath == NULL)
{
cleanup_workspace(workspace);
xml_ereport(ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
"XPath Syntax Error");
}
/* Now evaluate the path expression. */
res = xmlXPathCompiledEval(comppath, workspace->ctxt);
workspace->res = res;
xmlXPathFreeCompExpr(comppath);
if (res == NULL)
cleanup_workspace(workspace);
return res;
}
Datum
xpath_string(PG_FUNCTION_ARGS)
{
text *document = PG_GETARG_TEXT_P(0);
text *xpathsupp = PG_GETARG_TEXT_P(1); /* XPath expression */
xmlChar *xpath;
int32 pathsize;
text *xpres;
xmlXPathObjectPtr res;
xpath_workspace workspace;
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);
strncpy((char *) xpath, "string(", 7);
memcpy((char *) (xpath + 7), VARDATA(xpathsupp), pathsize);
xpath[pathsize + 7] = ')';
xpath[pathsize + 8] = '\0';
res = pgxml_xpath(document, xpath, &workspace);
xpres = pgxml_result_to_text(res, NULL, NULL, NULL);
cleanup_workspace(&workspace);
pfree(xpath);
if (xpres == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(xpres);
}
