contrib/xml2/xslt_proc.c

   1 /*
   2  * $PostgreSQL$
   3  *
   4  * XSLT processing functions (requiring libxslt)
   5  *
   6  * John Gray, for Torchbox 2003-04-01
   7  */
   8 #include "postgres.h"
   9
  10 #include "executor/spi.h"
  11 #include "fmgr.h"
  12 #include "funcapi.h"
  13 #include "miscadmin.h"
  14 #include "utils/builtins.h"
  15
  16 /* libxml includes */
  17
  18 #include <libxml/xpath.h>
  19 #include <libxml/tree.h>
  20 #include <libxml/xmlmemory.h>
  21
  22 /* libxslt includes */
  23
  24 #include <libxslt/xslt.h>
  25 #include <libxslt/xsltInternals.h>
  26 #include <libxslt/transform.h>
  27 #include <libxslt/xsltutils.h>
  28
  29
  30 /* declarations to come from xpath.c */
  31 extern void elog_error(int level, char *explain, int force);
  32 extern void pgxml_parser_init();
  33 extern xmlChar *pgxml_texttoxmlchar(text *textstring);
  34
  35 /* local defs */
  36 static void parse_params(const char **params, text *paramstr);
  37
  38 Datum           xslt_process(PG_FUNCTION_ARGS);
  39
  40
  41 #define MAXPARAMS 20
  42
  43 PG_FUNCTION_INFO_V1(xslt_process);
  44
  45 Datum
  46 xslt_process(PG_FUNCTION_ARGS)
  47 {
  48         text       *doct = PG_GETARG_TEXT_P(0);
  49         text       *ssheet = PG_GETARG_TEXT_P(1);
  50         text       *paramstr;
  51         const char *params[MAXPARAMS + 1];      /* +1 for the terminator */
  52         xsltStylesheetPtr stylesheet = NULL;
  53         xmlDocPtr       doctree;
  54         xmlDocPtr       restree;
  55         xmlDocPtr       ssdoc = NULL;
  56         xmlChar    *resstr;
  57         int                     resstat;
  58         int                     reslen;
  59
  60         if (fcinfo->nargs == 3)
  61         {
  62                 paramstr = PG_GETARG_TEXT_P(2);
  63                 parse_params(params, paramstr);
  64         }
  65         else
  66                 /* No parameters */
  67                 params[0] = NULL;
  68
  69         /* Setup parser */
  70         pgxml_parser_init();
  71
  72         /* Check to see if document is a file or a literal */
  73
  74         if (VARDATA(doct)[0] == '<')
  75                 doctree = xmlParseMemory((char *) VARDATA(doct), VARSIZE(doct) - VARHDRSZ);
  76         else
  77                 doctree = xmlParseFile(text_to_cstring(doct));
  78
  79         if (doctree == NULL)
  80         {
  81                 xmlCleanupParser();
  82                 elog_error(ERROR, "error parsing XML document", 0);
  83
  84                 PG_RETURN_NULL();
  85         }
  86
  87         /* Same for stylesheet */
  88         if (VARDATA(ssheet)[0] == '<')
  89         {
  90                 ssdoc = xmlParseMemory((char *) VARDATA(ssheet),
  91                                                            VARSIZE(ssheet) - VARHDRSZ);
  92                 if (ssdoc == NULL)
  93                 {
  94                         xmlFreeDoc(doctree);
  95                         xmlCleanupParser();
  96                         elog_error(ERROR, "error parsing stylesheet as XML document", 0);
  97                         PG_RETURN_NULL();
  98                 }
  99
 100                 stylesheet = xsltParseStylesheetDoc(ssdoc);
 101         }
 102         else
 103                 stylesheet = xsltParseStylesheetFile((xmlChar *) text_to_cstring(ssheet));
 104
 105
 106         if (stylesheet == NULL)
 107         {
 108                 xmlFreeDoc(doctree);
 109                 xsltCleanupGlobals();
 110                 xmlCleanupParser();
 111                 elog_error(ERROR, "failed to parse stylesheet", 0);
 112                 PG_RETURN_NULL();
 113         }
 114
 115         restree = xsltApplyStylesheet(stylesheet, doctree, params);
 116         resstat = xsltSaveResultToString(&resstr, &reslen, restree, stylesheet);
 117
 118         xsltFreeStylesheet(stylesheet);
 119         xmlFreeDoc(restree);
 120         xmlFreeDoc(doctree);
 121
 122         xsltCleanupGlobals();
 123         xmlCleanupParser();
 124
 125         if (resstat < 0)
 126                 PG_RETURN_NULL();
 127
 128         PG_RETURN_TEXT_P(cstring_to_text_with_len((char *) resstr, reslen));
 129 }
 130
 131
 132 void
 133 parse_params(const char **params, text *paramstr)
 134 {
 135         char       *pos;
 136         char       *pstr;
 137
 138         int                     i;
 139         char       *nvsep = "=";
 140         char       *itsep = ",";
 141
 142         pstr = text_to_cstring(paramstr);
 143
 144         pos = pstr;
 145
 146         for (i = 0; i < MAXPARAMS; i++)
 147         {
 148                 params[i] = pos;
 149                 pos = strstr(pos, nvsep);
 150                 if (pos != NULL)
 151                 {
 152                         *pos = '\0';
 153                         pos++;
 154                 }
 155                 else
 156                 {
 157                         params[i] = NULL;
 158                         break;
 159                 }
 160                 /* Value */
 161                 i++;
 162                 params[i] = pos;
 163                 pos = strstr(pos, itsep);
 164                 if (pos != NULL)
 165                 {
 166                         *pos = '\0';
 167                         pos++;
 168                 }
 169                 else
 170                         break;
 171
 172         }
 173         if (i < MAXPARAMS)
 174                 params[i + 1] = NULL;
 175 }