postgresql/contrib/xml2/xslt_proc.c
2011-04-10 11:42:00 -04:00

203 lines
4.0 KiB
C

/*
* contrib/xml2/xslt_proc.c
*
* XSLT processing functions (requiring libxslt)
*
* John Gray, for Torchbox 2003-04-01
*/
#include "postgres.h"
#include "executor/spi.h"
#include "fmgr.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/xml.h"
#ifdef USE_LIBXSLT
/* libxml includes */
#include <libxml/xpath.h>
#include <libxml/tree.h>
#include <libxml/xmlmemory.h>
/* libxslt includes */
#include <libxslt/xslt.h>
#include <libxslt/xsltInternals.h>
#include <libxslt/transform.h>
#include <libxslt/xsltutils.h>
#endif /* USE_LIBXSLT */
/* externally accessible functions */
Datum xslt_process(PG_FUNCTION_ARGS);
#ifdef USE_LIBXSLT
/* declarations to come from xpath.c */
extern void pgxml_parser_init(void);
/* local defs */
static const char **parse_params(text *paramstr);
#endif /* USE_LIBXSLT */
PG_FUNCTION_INFO_V1(xslt_process);
Datum
xslt_process(PG_FUNCTION_ARGS)
{
#ifdef USE_LIBXSLT
text *doct = PG_GETARG_TEXT_P(0);
text *ssheet = PG_GETARG_TEXT_P(1);
text *paramstr;
const char **params;
xsltStylesheetPtr stylesheet = NULL;
xmlDocPtr doctree;
xmlDocPtr restree;
xmlDocPtr ssdoc = NULL;
xmlChar *resstr;
int resstat;
int reslen;
if (fcinfo->nargs == 3)
{
paramstr = PG_GETARG_TEXT_P(2);
params = parse_params(paramstr);
}
else
{
/* No parameters */
params = (const char **) palloc(sizeof(char *));
params[0] = NULL;
}
/* Setup parser */
pgxml_parser_init();
/* Check to see if document is a file or a literal */
if (VARDATA(doct)[0] == '<')
doctree = xmlParseMemory((char *) VARDATA(doct), VARSIZE(doct) - VARHDRSZ);
else
doctree = xmlParseFile(text_to_cstring(doct));
if (doctree == NULL)
xml_ereport(ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
"error parsing XML document");
/* Same for stylesheet */
if (VARDATA(ssheet)[0] == '<')
{
ssdoc = xmlParseMemory((char *) VARDATA(ssheet),
VARSIZE(ssheet) - VARHDRSZ);
if (ssdoc == NULL)
{
xmlFreeDoc(doctree);
xml_ereport(ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
"error parsing stylesheet as XML document");
}
stylesheet = xsltParseStylesheetDoc(ssdoc);
}
else
stylesheet = xsltParseStylesheetFile((xmlChar *) text_to_cstring(ssheet));
if (stylesheet == NULL)
{
xmlFreeDoc(doctree);
xsltCleanupGlobals();
xml_ereport(ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
"failed to parse stylesheet");
}
restree = xsltApplyStylesheet(stylesheet, doctree, params);
resstat = xsltSaveResultToString(&resstr, &reslen, restree, stylesheet);
xsltFreeStylesheet(stylesheet);
xmlFreeDoc(restree);
xmlFreeDoc(doctree);
xsltCleanupGlobals();
if (resstat < 0)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(cstring_to_text_with_len((char *) resstr, reslen));
#else /* !USE_LIBXSLT */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("xslt_process() is not available without libxslt")));
PG_RETURN_NULL();
#endif /* USE_LIBXSLT */
}
#ifdef USE_LIBXSLT
static const char **
parse_params(text *paramstr)
{
char *pos;
char *pstr;
char *nvsep = "=";
char *itsep = ",";
const char **params;
int max_params;
int nparams;
pstr = text_to_cstring(paramstr);
max_params = 20; /* must be even! */
params = (const char **) palloc((max_params + 1) * sizeof(char *));
nparams = 0;
pos = pstr;
while (*pos != '\0')
{
if (nparams >= max_params)
{
max_params *= 2;
params = (const char **) repalloc(params,
(max_params + 1) * sizeof(char *));
}
params[nparams++] = pos;
pos = strstr(pos, nvsep);
if (pos != NULL)
{
*pos = '\0';
pos++;
}
else
{
/* No equal sign, so ignore this "parameter" */
nparams--;
break;
}
/* since max_params is even, we still have nparams < max_params */
params[nparams++] = pos;
pos = strstr(pos, itsep);
if (pos != NULL)
{
*pos = '\0';
pos++;
}
else
break;
}
/* Add the terminator marker; we left room for it in the palloc's */
params[nparams] = NULL;
return params;
}
#endif /* USE_LIBXSLT */