xslt_proc.c File Reference

#include "postgres.h"
#include "fmgr.h"
#include "utils/builtins.h"
#include "utils/xml.h"
#include "varatt.h"

Include dependency graph for xslt_proc.c:

Go to the source code of this file.

Functions
	PG_FUNCTION_INFO_V1 (xslt_process)
Datum	xslt_process (PG_FUNCTION_ARGS)

Function Documentation

PG_FUNCTION_INFO_V1()

PG_FUNCTION_INFO_V1

(

xslt_process

)

xslt_process()

Datum xslt_process

(

PG_FUNCTION_ARGS

)

Definition at line 46 of file xslt_proc.c.

{
#ifdef USE_LIBXSLT
 
    text       *doct = PG_GETARG_TEXT_PP(0);
    text       *ssheet = PG_GETARG_TEXT_PP(1);
    text       *volatile result = NULL;
    text       *paramstr;
    const char **params;
    PgXmlErrorContext *xmlerrcxt;
    volatile xsltStylesheetPtr stylesheet = NULL;
    volatile xmlDocPtr doctree = NULL;
    volatile xmlDocPtr restree = NULL;
    volatile xsltSecurityPrefsPtr xslt_sec_prefs = NULL;
    volatile xsltTransformContextPtr xslt_ctxt = NULL;
    volatile int resstat = -1;
    xmlChar    *volatile resstr = NULL;
 
    if (fcinfo->nargs == 3)
    {
        paramstr = PG_GETARG_TEXT_PP(2);
        params = parse_params(paramstr);
    }
    else
    {
        /* No parameters */
        params = palloc_object(const char *);
        params[0] = NULL;
    }
 
    /* Setup parser */
    xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
 
    PG_TRY();
    {
        xmlDocPtr   ssdoc;
        bool        xslt_sec_prefs_error;
        int         reslen = 0;
 
        /* Parse document */
        doctree = xmlReadMemory((char *) VARDATA_ANY(doct),
                                VARSIZE_ANY_EXHDR(doct), NULL, NULL,
                                XML_PARSE_NOENT);
 
        if (doctree == NULL || pg_xml_error_occurred(xmlerrcxt))
            xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_XML_DOCUMENT,
                        "error parsing XML document");
 
        /* Same for stylesheet */
        ssdoc = xmlReadMemory((char *) VARDATA_ANY(ssheet),
                              VARSIZE_ANY_EXHDR(ssheet), NULL, NULL,
                              XML_PARSE_NOENT);
 
        if (ssdoc == NULL || pg_xml_error_occurred(xmlerrcxt))
            xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_XML_DOCUMENT,
                        "error parsing stylesheet as XML document");
 
        /* After this call we need not free ssdoc separately */
        stylesheet = xsltParseStylesheetDoc(ssdoc);
 
        if (stylesheet == NULL || pg_xml_error_occurred(xmlerrcxt))
            xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
                        "failed to parse stylesheet");
 
        xslt_ctxt = xsltNewTransformContext(stylesheet, doctree);
 
        xslt_sec_prefs_error = false;
        if ((xslt_sec_prefs = xsltNewSecurityPrefs()) == NULL)
            xslt_sec_prefs_error = true;
 
        if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_READ_FILE,
                                 xsltSecurityForbid) != 0)
            xslt_sec_prefs_error = true;
        if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_WRITE_FILE,
                                 xsltSecurityForbid) != 0)
            xslt_sec_prefs_error = true;
        if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_CREATE_DIRECTORY,
                                 xsltSecurityForbid) != 0)
            xslt_sec_prefs_error = true;
        if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_READ_NETWORK,
                                 xsltSecurityForbid) != 0)
            xslt_sec_prefs_error = true;
        if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_WRITE_NETWORK,
                                 xsltSecurityForbid) != 0)
            xslt_sec_prefs_error = true;
        if (xsltSetCtxtSecurityPrefs(xslt_sec_prefs, xslt_ctxt) != 0)
            xslt_sec_prefs_error = true;
 
        if (xslt_sec_prefs_error)
            ereport(ERROR,
                    (errmsg("could not set libxslt security preferences")));
 
        restree = xsltApplyStylesheetUser(stylesheet, doctree, params,
                                          NULL, NULL, xslt_ctxt);
 
        if (restree == NULL || pg_xml_error_occurred(xmlerrcxt))
            xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
                        "failed to apply stylesheet");
 
        resstat = xsltSaveResultToString((xmlChar **) &resstr, &reslen,
                                         restree, stylesheet);
 
        if (resstat >= 0)
        {
            /*
             * If an empty string has been returned, resstr would be NULL. In
             * this case, assume that the result is an empty string.
             */
            if (reslen == 0)
                result = cstring_to_text("");
            else
                result = cstring_to_text_with_len((char *) resstr, reslen);
        }
    }
    PG_CATCH();
    {
        if (restree != NULL)
            xmlFreeDoc(restree);
        if (xslt_ctxt != NULL)
            xsltFreeTransformContext(xslt_ctxt);
        if (xslt_sec_prefs != NULL)
            xsltFreeSecurityPrefs(xslt_sec_prefs);
        if (stylesheet != NULL)
            xsltFreeStylesheet(stylesheet);
        if (doctree != NULL)
            xmlFreeDoc(doctree);
        if (resstr != NULL)
            xmlFree(resstr);
        xsltCleanupGlobals();
 
        pg_xml_done(xmlerrcxt, true);
 
        PG_RE_THROW();
    }
    PG_END_TRY();
 
    xmlFreeDoc(restree);
    xsltFreeTransformContext(xslt_ctxt);
    xsltFreeSecurityPrefs(xslt_sec_prefs);
    xsltFreeStylesheet(stylesheet);
    xmlFreeDoc(doctree);
    xsltCleanupGlobals();
 
    if (resstr)
        xmlFree(resstr);
 
    pg_xml_done(xmlerrcxt, false);
 
    /* XXX this is pretty dubious, really ought to throw error instead */
    if (resstat < 0)
        PG_RETURN_NULL();
 
    PG_RETURN_TEXT_P(result);
#else                           /* !USE_LIBXSLT */
 
    ereport(ERROR,
            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
             errmsg("xslt_process() is not available without libxslt")));
    PG_RETURN_NULL();
#endif                          /* USE_LIBXSLT */
}

References cstring_to_text(), cstring_to_text_with_len(), ereport, errcode(), errmsg, ERROR, fb(), palloc_object, PG_CATCH, PG_END_TRY, PG_GETARG_TEXT_PP, PG_RE_THROW, PG_RETURN_NULL, PG_RETURN_TEXT_P, PG_TRY, pg_xml_done(), pg_xml_error_occurred(), PG_XML_STRICTNESS_LEGACY, pgxml_parser_init(), result, VARDATA_ANY(), VARSIZE_ANY_EXHDR(), and xml_ereport().