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                    /* must be even, see parse_params() */
  42
  43
  44 PG_FUNCTION_INFO_V1(xslt_process);
  45
  46 Datum
  47 xslt_process(PG_FUNCTION_ARGS)
  48 {
  49         text       *doct = PG_GETARG_TEXT_P(0);
  50         text       *ssheet = PG_GETARG_TEXT_P(1);
  51         text       *paramstr;
  52         const char *params[MAXPARAMS + 1];      /* +1 for the terminator */
  53         xsltStylesheetPtr stylesheet = NULL;
  54         xmlDocPtr       doctree;
  55         xmlDocPtr       restree;
  56         xmlDocPtr       ssdoc = NULL;
  57         xmlChar    *resstr;
  58         int                     resstat;
  59         int                     reslen;
  60
  61         if (fcinfo->nargs == 3)
  62         {
  63                 paramstr = PG_GETARG_TEXT_P(2);
  64                 parse_params(params, paramstr);
  65         }
  66         else
  67                 /* No parameters */
  68                 params[0] = NULL;
  69
  70         /* Setup parser */
  71         pgxml_parser_init();
  72
  73         /* Check to see if document is a file or a literal */
  74
  75         if (VARDATA(doct)[0] == '<')
  76                 doctree = xmlParseMemory((char *) VARDATA(doct), VARSIZE(doct) - VARHDRSZ);
  77         else
  78                 doctree = xmlParseFile(text_to_cstring(doct));
  79
  80         if (doctree == NULL)
  81         {
  82                 xmlCleanupParser();
  83                 elog_error(ERROR, "error parsing XML document", 0);
  84
  85                 PG_RETURN_NULL();
  86         }
  87
  88         /* Same for stylesheet */
  89         if (VARDATA(ssheet)[0] == '<')
  90         {
  91                 ssdoc = xmlParseMemory((char *) VARDATA(ssheet),
  92                                                            VARSIZE(ssheet) - VARHDRSZ);
  93                 if (ssdoc == NULL)
  94                 {
  95                         xmlFreeDoc(doctree);
  96                         xmlCleanupParser();
  97                         elog_error(ERROR, "error parsing stylesheet as XML document", 0);
  98                         PG_RETURN_NULL();
  99                 }
 100
 101                 stylesheet = xsltParseStylesheetDoc(ssdoc);
 102         }
 103         else
 104                 stylesheet = xsltParseStylesheetFile((xmlChar *) text_to_cstring(ssheet));
 105
 106
 107         if (stylesheet == NULL)
 108         {
 109                 xmlFreeDoc(doctree);
 110                 xsltCleanupGlobals();
 111                 xmlCleanupParser();
 112                 elog_error(ERROR, "failed to parse stylesheet", 0);
 113                 PG_RETURN_NULL();
 114         }
 115
 116         restree = xsltApplyStylesheet(stylesheet, doctree, params);
 117         resstat = xsltSaveResultToString(&resstr, &reslen, restree, stylesheet);
 118
 119         xsltFreeStylesheet(stylesheet);
 120         xmlFreeDoc(restree);
 121         xmlFreeDoc(doctree);
 122
 123         xsltCleanupGlobals();
 124         xmlCleanupParser();
 125
 126         if (resstat < 0)
 127                 PG_RETURN_NULL();
 128
 129         PG_RETURN_TEXT_P(cstring_to_text_with_len((char *) resstr, reslen));
 130 }
 131
 132
 133 static void
 134 parse_params(const char **params, text *paramstr)
 135 {
 136         char       *pos;
 137         char       *pstr;
 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                         /* No equal sign, so ignore this "parameter" */
 158                         /* We'll reset params[i] to NULL below the loop */
 159                         break;
 160                 }
 161                 /* Value */
 162                 i++;
 163                 /* since MAXPARAMS is even, we still have i < MAXPARAMS */
 164                 params[i] = pos;
 165                 pos = strstr(pos, itsep);
 166                 if (pos != NULL)
 167                 {
 168                         *pos = '\0';
 169                         pos++;
 170                 }
 171                 else
 172                 {
 173                         i++;
 174                         break;
 175                 }
 176         }
 177
 178         params[i] = NULL;
 179 }