third_party/libxslt/libexslt/saxon.c

   1 #define IN_LIBEXSLT
   2 #include "libexslt/libexslt.h"
   3
   4 #if defined(WIN32) && !defined (__CYGWIN__) && (!__MINGW32__)
   5 #include <win32config.h>
   6 #else
   7 #include "config.h"
   8 #endif
   9
  10 #include <libxml/tree.h>
  11 #include <libxml/xpath.h>
  12 #include <libxml/xpathInternals.h>
  13 #include <libxml/parser.h>
  14 #include <libxml/hash.h>
  15
  16 #include <libxslt/xsltconfig.h>
  17 #include <libxslt/xsltutils.h>
  18 #include <libxslt/xsltInternals.h>
  19 #include <libxslt/extensions.h>
  20
  21 #include "exslt.h"
  22
  23 /**
  24  * exsltSaxonInit:
  25  * @ctxt: an XSLT transformation context
  26  * @URI: the namespace URI for the extension
  27  *
  28  * Initializes the SAXON module.
  29  *
  30  * Returns the data for this transformation
  31  */
  32 static xmlHashTablePtr
  33 exsltSaxonInit (xsltTransformContextPtr ctxt ATTRIBUTE_UNUSED,
  34                 const xmlChar *URI ATTRIBUTE_UNUSED) {
  35     return xmlHashCreate(1);
  36 }
  37
  38 /**
  39  * exsltSaxonShutdown:
  40  * @ctxt: an XSLT transformation context
  41  * @URI: the namespace URI for the extension
  42  * @data: the module data to free up
  43  *
  44  * Shutdown the SAXON extension module
  45  */
  46 static void
  47 exsltSaxonShutdown (xsltTransformContextPtr ctxt ATTRIBUTE_UNUSED,
  48                     const xmlChar *URI ATTRIBUTE_UNUSED,
  49                     xmlHashTablePtr data) {
  50     xmlHashFree(data, (xmlHashDeallocator) xmlXPathFreeCompExpr);
  51 }
  52
  53
  54 /**
  55  * exsltSaxonExpressionFunction:
  56  * @ctxt: an XPath parser context
  57  * @nargs: the number of arguments
  58  *
  59  * The supplied string must contain an XPath expression. The result of
  60  * the function is a stored expression, which may be supplied as an
  61  * argument to other extension functions such as saxon:eval(),
  62  * saxon:sum() and saxon:distinct(). The result of the expression will
  63  * usually depend on the current node. The expression may contain
  64  * references to variables that are in scope at the point where
  65  * saxon:expression() is called: these variables will be replaced in
  66  * the stored expression with the values they take at the time
  67  * saxon:expression() is called, not the values of the variables at
  68  * the time the stored expression is evaluated.  Similarly, if the
  69  * expression contains namespace prefixes, these are interpreted in
  70  * terms of the namespace declarations in scope at the point where the
  71  * saxon:expression() function is called, not those in scope where the
  72  * stored expression is evaluated.
  73  *
  74  * TODO: current implementation doesn't conform to SAXON behaviour
  75  * regarding context and namespaces.
  76  */
  77 static void
  78 exsltSaxonExpressionFunction (xmlXPathParserContextPtr ctxt, int nargs) {
  79     xmlChar *arg;
  80     xmlXPathCompExprPtr ret;
  81     xmlHashTablePtr hash;
  82     xsltTransformContextPtr tctxt = xsltXPathGetTransformContext(ctxt);
  83
  84     if (nargs != 1) {
  85         xmlXPathSetArityError(ctxt);
  86         return;
  87     }
  88
  89     arg = xmlXPathPopString(ctxt);
  90     if (xmlXPathCheckError(ctxt) || (arg == NULL)) {
  91         xmlXPathSetTypeError(ctxt);
  92         return;
  93     }
  94
  95     hash = (xmlHashTablePtr) xsltGetExtData(tctxt,
  96                                             ctxt->context->functionURI);
  97
  98     ret = xmlHashLookup(hash, arg);
  99
 100     if (ret == NULL) {
 101          ret = xmlXPathCompile(arg);
 102          if (ret == NULL) {
 103               xmlFree(arg);
 104               xsltGenericError(xsltGenericErrorContext,
 105                         "{%s}:%s: argument is not an XPath expression\n",
 106                         ctxt->context->functionURI, ctxt->context->function);
 107               return;
 108          }
 109          xmlHashAddEntry(hash, arg, (void *) ret);
 110     }
 111
 112     xmlFree(arg);
 113
 114     xmlXPathReturnExternal(ctxt, ret);
 115 }
 116
 117 /**
 118  * exsltSaxonEvalFunction:
 119  * @ctxt:  an XPath parser context
 120  * @nargs:  number of arguments
 121  *
 122  * Implements de SAXON eval() function:
 123  *    object saxon:eval (saxon:stored-expression)
 124  * Returns the result of evaluating the supplied stored expression.
 125  * A stored expression may be obtained as the result of calling
 126  * the saxon:expression() function.
 127  * The stored expression is evaluated in the current context, that
 128  * is, the context node is the current node, and the context position
 129  * and context size are the same as the result of calling position()
 130  * or last() respectively.
 131  */
 132 static void
 133 exsltSaxonEvalFunction (xmlXPathParserContextPtr ctxt, int nargs) {
 134      xmlXPathCompExprPtr expr;
 135      xmlXPathObjectPtr ret;
 136
 137      if (nargs != 1) {
 138           xmlXPathSetArityError(ctxt);
 139           return;
 140      }
 141
 142      if (!xmlXPathStackIsExternal(ctxt)) {
 143           xmlXPathSetTypeError(ctxt);
 144           return;
 145      }
 146
 147      expr = (xmlXPathCompExprPtr) xmlXPathPopExternal(ctxt);
 148
 149      ret = xmlXPathCompiledEval(expr, ctxt->context);
 150
 151      valuePush(ctxt, ret);
 152 }
 153
 154 /**
 155  * exsltSaxonEvaluateFunction:
 156  * @ctxt:  an XPath parser context
 157  * @nargs: number of arguments
 158  *
 159  * Implements the SAXON evaluate() function
 160  *     object saxon:evaluate (string)
 161  * The supplied string must contain an XPath expression. The result of
 162  * the function is the result of evaluating the XPath expression. This
 163  * is useful where an expression needs to be constructed at run-time or
 164  * passed to the stylesheet as a parameter, for example where the sort
 165  * key is determined dynamically. The context for the expression (e.g.
 166  * which variables and namespaces are available) is exactly the same as
 167  * if the expression were written explicitly at this point in the
 168  * stylesheet. The function saxon:evaluate(string) is shorthand for
 169  * saxon:eval(saxon:expression(string)).
 170  */
 171 static void
 172 exsltSaxonEvaluateFunction (xmlXPathParserContextPtr ctxt, int nargs) {
 173      if (nargs != 1) {
 174           xmlXPathSetArityError(ctxt);
 175           return;
 176      }
 177
 178      exsltSaxonExpressionFunction(ctxt, 1);
 179      exsltSaxonEvalFunction(ctxt, 1);
 180 }
 181
 182 /**
 183  * exsltSaxonLineNumberFunction:
 184  * @ctxt:  an XPath parser context
 185  * @nargs: number of arguments
 186  *
 187  * Implements the SAXON line-number() function
 188  *     integer saxon:line-number()
 189  *
 190  * This returns the line number of the context node in the source document
 191  * within the entity that contains it. There are no arguments. If line numbers
 192  * are not maintained for the current document, the function returns -1. (To
 193  * ensure that line numbers are maintained, use the -l option on the command
 194  * line)
 195  *
 196  * The extension has been extended to have the following form:
 197  *     integer saxon:line-number([node-set-1])
 198  * If a node-set is given, this extension will return the line number of the
 199  * node in the argument node-set that is first in document order.
 200  */
 201 static void
 202 exsltSaxonLineNumberFunction(xmlXPathParserContextPtr ctxt, int nargs) {
 203     xmlNodePtr cur = NULL;
 204
 205     if (nargs == 0) {
 206         cur = ctxt->context->node;
 207     } else if (nargs == 1) {
 208         xmlXPathObjectPtr obj;
 209         xmlNodeSetPtr nodelist;
 210         int i;
 211
 212         if ((ctxt->value == NULL) || (ctxt->value->type != XPATH_NODESET)) {
 213             xsltTransformError(xsltXPathGetTransformContext(ctxt), NULL, NULL,
 214                 "saxon:line-number() : invalid arg expecting a node-set\n");
 215             ctxt->error = XPATH_INVALID_TYPE;
 216             return;
 217         }
 218
 219         obj = valuePop(ctxt);
 220         nodelist = obj->nodesetval;
 221         if ((nodelist == NULL) || (nodelist->nodeNr <= 0)) {
 222             xmlXPathFreeObject(obj);
 223             valuePush(ctxt, xmlXPathNewFloat(-1));
 224             return;
 225         }
 226         cur = nodelist->nodeTab[0];
 227         for (i = 1;i < nodelist->nodeNr;i++) {
 228             int ret = xmlXPathCmpNodes(cur, nodelist->nodeTab[i]);
 229             if (ret == -1)
 230                 cur = nodelist->nodeTab[i];
 231         }
 232         xmlXPathFreeObject(obj);
 233     } else {
 234         xsltTransformError(xsltXPathGetTransformContext(ctxt), NULL, NULL,
 235                 "saxon:line-number() : invalid number of args %d\n",
 236                 nargs);
 237         ctxt->error = XPATH_INVALID_ARITY;
 238         return;
 239     }
 240
 241     valuePush(ctxt, xmlXPathNewFloat(xmlGetLineNo(cur)));
 242     return;
 243 }
 244
 245 /**
 246  * exsltSaxonRegister:
 247  *
 248  * Registers the SAXON extension module
 249  */
 250 void
 251 exsltSaxonRegister (void) {
 252      xsltRegisterExtModule (SAXON_NAMESPACE,
 253                             (xsltExtInitFunction) exsltSaxonInit,
 254                             (xsltExtShutdownFunction) exsltSaxonShutdown);
 255      xsltRegisterExtModuleFunction((const xmlChar *) "expression",
 256                                    SAXON_NAMESPACE,
 257                                    exsltSaxonExpressionFunction);
 258      xsltRegisterExtModuleFunction((const xmlChar *) "eval",
 259                                    SAXON_NAMESPACE,
 260                                    exsltSaxonEvalFunction);
 261      xsltRegisterExtModuleFunction((const xmlChar *) "evaluate",
 262                                    SAXON_NAMESPACE,
 263                                    exsltSaxonEvaluateFunction);
 264     xsltRegisterExtModuleFunction ((const xmlChar *) "line-number",
 265                                    SAXON_NAMESPACE,
 266                                    exsltSaxonLineNumberFunction);
 267 }