1/*
2 * Summary: XML Path Language implementation
3 * Description: API for the XML Path Language implementation
4 *
5 * XML Path Language implementation
6 * XPath is a language for addressing parts of an XML document,
7 * designed to be used by both XSLT and XPointer
8 * http://www.w3.org/TR/xpath
9 *
10 * Implements
11 * W3C Recommendation 16 November 1999
12 * http://www.w3.org/TR/1999/REC-xpath-19991116
13 *
14 * Copy: See Copyright for the status of this software.
15 *
16 * Author: Daniel Veillard
17 */
18
19#ifndef __XML_XPATH_H__
20#define __XML_XPATH_H__
21
22#include <libxml/xmlversion.h>
23
24#ifdef LIBXML_XPATH_ENABLED
25
26#include <libxml/xmlerror.h>
27#include <libxml/tree.h>
28#include <libxml/hash.h>
29#endif /* LIBXML_XPATH_ENABLED */
30
31#if defined(LIBXML_XPATH_ENABLED) || defined(LIBXML_SCHEMAS_ENABLED)
32#ifdef __cplusplus
33extern "C" {
34#endif
35#endif /* LIBXML_XPATH_ENABLED or LIBXML_SCHEMAS_ENABLED */
36
37#ifdef LIBXML_XPATH_ENABLED
38
39typedef struct _xmlXPathContext xmlXPathContext;
40typedef xmlXPathContext *xmlXPathContextPtr;
41typedef struct _xmlXPathParserContext xmlXPathParserContext;
42typedef xmlXPathParserContext *xmlXPathParserContextPtr;
43
44/**
45 * The set of XPath error codes.
46 */
47
48typedef enum {
49 XPATH_EXPRESSION_OK = 0,
50 XPATH_NUMBER_ERROR,
51 XPATH_UNFINISHED_LITERAL_ERROR,
52 XPATH_START_LITERAL_ERROR,
53 XPATH_VARIABLE_REF_ERROR,
54 XPATH_UNDEF_VARIABLE_ERROR,
55 XPATH_INVALID_PREDICATE_ERROR,
56 XPATH_EXPR_ERROR,
57 XPATH_UNCLOSED_ERROR,
58 XPATH_UNKNOWN_FUNC_ERROR,
59 XPATH_INVALID_OPERAND,
60 XPATH_INVALID_TYPE,
61 XPATH_INVALID_ARITY,
62 XPATH_INVALID_CTXT_SIZE,
63 XPATH_INVALID_CTXT_POSITION,
64 XPATH_MEMORY_ERROR,
65 XPTR_SYNTAX_ERROR,
66 XPTR_RESOURCE_ERROR,
67 XPTR_SUB_RESOURCE_ERROR,
68 XPATH_UNDEF_PREFIX_ERROR,
69 XPATH_ENCODING_ERROR,
70 XPATH_INVALID_CHAR_ERROR,
71 XPATH_INVALID_CTXT,
72 XPATH_STACK_ERROR,
73 XPATH_FORBID_VARIABLE_ERROR,
74 XPATH_OP_LIMIT_EXCEEDED,
75 XPATH_RECURSION_LIMIT_EXCEEDED
76} xmlXPathError;
77
78/*
79 * A node-set (an unordered collection of nodes without duplicates).
80 */
81typedef struct _xmlNodeSet xmlNodeSet;
82typedef xmlNodeSet *xmlNodeSetPtr;
83struct _xmlNodeSet {
84 int nodeNr; /* number of nodes in the set */
85 int nodeMax; /* size of the array as allocated */
86 xmlNodePtr *nodeTab; /* array of nodes in no particular order */
87 /* @@ with_ns to check whether namespace nodes should be looked at @@ */
88};
89
90/*
91 * An expression is evaluated to yield an object, which
92 * has one of the following four basic types:
93 * - node-set
94 * - boolean
95 * - number
96 * - string
97 *
98 * @@ XPointer will add more types !
99 */
100
101typedef enum {
102 XPATH_UNDEFINED = 0,
103 XPATH_NODESET = 1,
104 XPATH_BOOLEAN = 2,
105 XPATH_NUMBER = 3,
106 XPATH_STRING = 4,
107 XPATH_POINT = 5,
108 XPATH_RANGE = 6,
109 XPATH_LOCATIONSET = 7,
110 XPATH_USERS = 8,
111 XPATH_XSLT_TREE = 9 /* An XSLT value tree, non modifiable */
112} xmlXPathObjectType;
113
114typedef struct _xmlXPathObject xmlXPathObject;
115typedef xmlXPathObject *xmlXPathObjectPtr;
116struct _xmlXPathObject {
117 xmlXPathObjectType type;
118 xmlNodeSetPtr nodesetval;
119 int boolval;
120 double floatval;
121 xmlChar *stringval;
122 void *user;
123 int index;
124 void *user2;
125 int index2;
126};
127
128/**
129 * xmlXPathConvertFunc:
130 * @obj: an XPath object
131 * @type: the number of the target type
132 *
133 * A conversion function is associated to a type and used to cast
134 * the new type to primitive values.
135 *
136 * Returns -1 in case of error, 0 otherwise
137 */
138typedef int (*xmlXPathConvertFunc) (xmlXPathObjectPtr obj, int type);
139
140/*
141 * Extra type: a name and a conversion function.
142 */
143
144typedef struct _xmlXPathType xmlXPathType;
145typedef xmlXPathType *xmlXPathTypePtr;
146struct _xmlXPathType {
147 const xmlChar *name; /* the type name */
148 xmlXPathConvertFunc func; /* the conversion function */
149};
150
151/*
152 * Extra variable: a name and a value.
153 */
154
155typedef struct _xmlXPathVariable xmlXPathVariable;
156typedef xmlXPathVariable *xmlXPathVariablePtr;
157struct _xmlXPathVariable {
158 const xmlChar *name; /* the variable name */
159 xmlXPathObjectPtr value; /* the value */
160};
161
162/**
163 * xmlXPathEvalFunc:
164 * @ctxt: an XPath parser context
165 * @nargs: the number of arguments passed to the function
166 *
167 * An XPath evaluation function, the parameters are on the XPath context stack.
168 */
169
170typedef void (*xmlXPathEvalFunc)(xmlXPathParserContextPtr ctxt,
171 int nargs);
172
173/*
174 * Extra function: a name and a evaluation function.
175 */
176
177typedef struct _xmlXPathFunct xmlXPathFunct;
178typedef xmlXPathFunct *xmlXPathFuncPtr;
179struct _xmlXPathFunct {
180 const xmlChar *name; /* the function name */
181 xmlXPathEvalFunc func; /* the evaluation function */
182};
183
184/**
185 * xmlXPathAxisFunc:
186 * @ctxt: the XPath interpreter context
187 * @cur: the previous node being explored on that axis
188 *
189 * An axis traversal function. To traverse an axis, the engine calls
190 * the first time with cur == NULL and repeat until the function returns
191 * NULL indicating the end of the axis traversal.
192 *
193 * Returns the next node in that axis or NULL if at the end of the axis.
194 */
195
196typedef xmlXPathObjectPtr (*xmlXPathAxisFunc) (xmlXPathParserContextPtr ctxt,
197 xmlXPathObjectPtr cur);
198
199/*
200 * Extra axis: a name and an axis function.
201 */
202
203typedef struct _xmlXPathAxis xmlXPathAxis;
204typedef xmlXPathAxis *xmlXPathAxisPtr;
205struct _xmlXPathAxis {
206 const xmlChar *name; /* the axis name */
207 xmlXPathAxisFunc func; /* the search function */
208};
209
210/**
211 * xmlXPathFunction:
212 * @ctxt: the XPath interprestation context
213 * @nargs: the number of arguments
214 *
215 * An XPath function.
216 * The arguments (if any) are popped out from the context stack
217 * and the result is pushed on the stack.
218 */
219
220typedef void (*xmlXPathFunction) (xmlXPathParserContextPtr ctxt, int nargs);
221
222/*
223 * Function and Variable Lookup.
224 */
225
226/**
227 * xmlXPathVariableLookupFunc:
228 * @ctxt: an XPath context
229 * @name: name of the variable
230 * @ns_uri: the namespace name hosting this variable
231 *
232 * Prototype for callbacks used to plug variable lookup in the XPath
233 * engine.
234 *
235 * Returns the XPath object value or NULL if not found.
236 */
237typedef xmlXPathObjectPtr (*xmlXPathVariableLookupFunc) (void *ctxt,
238 const xmlChar *name,
239 const xmlChar *ns_uri);
240
241/**
242 * xmlXPathFuncLookupFunc:
243 * @ctxt: an XPath context
244 * @name: name of the function
245 * @ns_uri: the namespace name hosting this function
246 *
247 * Prototype for callbacks used to plug function lookup in the XPath
248 * engine.
249 *
250 * Returns the XPath function or NULL if not found.
251 */
252typedef xmlXPathFunction (*xmlXPathFuncLookupFunc) (void *ctxt,
253 const xmlChar *name,
254 const xmlChar *ns_uri);
255
256/**
257 * xmlXPathFlags:
258 * Flags for XPath engine compilation and runtime
259 */
260/**
261 * XML_XPATH_CHECKNS:
262 *
263 * check namespaces at compilation
264 */
265#define XML_XPATH_CHECKNS (1<<0)
266/**
267 * XML_XPATH_NOVAR:
268 *
269 * forbid variables in expression
270 */
271#define XML_XPATH_NOVAR (1<<1)
272
273/**
274 * xmlXPathContext:
275 *
276 * Expression evaluation occurs with respect to a context.
277 * he context consists of:
278 * - a node (the context node)
279 * - a node list (the context node list)
280 * - a set of variable bindings
281 * - a function library
282 * - the set of namespace declarations in scope for the expression
283 * Following the switch to hash tables, this need to be trimmed up at
284 * the next binary incompatible release.
285 * The node may be modified when the context is passed to libxml2
286 * for an XPath evaluation so you may need to initialize it again
287 * before the next call.
288 */
289
290struct _xmlXPathContext {
291 xmlDocPtr doc; /* The current document */
292 xmlNodePtr node; /* The current node */
293
294 int nb_variables_unused; /* unused (hash table) */
295 int max_variables_unused; /* unused (hash table) */
296 xmlHashTablePtr varHash; /* Hash table of defined variables */
297
298 int nb_types; /* number of defined types */
299 int max_types; /* max number of types */
300 xmlXPathTypePtr types; /* Array of defined types */
301
302 int nb_funcs_unused; /* unused (hash table) */
303 int max_funcs_unused; /* unused (hash table) */
304 xmlHashTablePtr funcHash; /* Hash table of defined funcs */
305
306 int nb_axis; /* number of defined axis */
307 int max_axis; /* max number of axis */
308 xmlXPathAxisPtr axis; /* Array of defined axis */
309
310 /* the namespace nodes of the context node */
311 xmlNsPtr *namespaces; /* Array of namespaces */
312 int nsNr; /* number of namespace in scope */
313 void *user; /* function to free */
314
315 /* extra variables */
316 int contextSize; /* the context size */
317 int proximityPosition; /* the proximity position */
318
319 /* extra stuff for XPointer */
320 int xptr; /* is this an XPointer context? */
321 xmlNodePtr here; /* for here() */
322 xmlNodePtr origin; /* for origin() */
323
324 /* the set of namespace declarations in scope for the expression */
325 xmlHashTablePtr nsHash; /* The namespaces hash table */
326 xmlXPathVariableLookupFunc varLookupFunc;/* variable lookup func */
327 void *varLookupData; /* variable lookup data */
328
329 /* Possibility to link in an extra item */
330 void *extra; /* needed for XSLT */
331
332 /* The function name and URI when calling a function */
333 const xmlChar *function;
334 const xmlChar *functionURI;
335
336 /* function lookup function and data */
337 xmlXPathFuncLookupFunc funcLookupFunc;/* function lookup func */
338 void *funcLookupData; /* function lookup data */
339
340 /* temporary namespace lists kept for walking the namespace axis */
341 xmlNsPtr *tmpNsList; /* Array of namespaces */
342 int tmpNsNr; /* number of namespaces in scope */
343
344 /* error reporting mechanism */
345 void *userData; /* user specific data block */
346 xmlStructuredErrorFunc error; /* the callback in case of errors */
347 xmlError lastError; /* the last error */
348 xmlNodePtr debugNode; /* the source node XSLT */
349
350 /* dictionary */
351 xmlDictPtr dict; /* dictionary if any */
352
353 int flags; /* flags to control compilation */
354
355 /* Cache for reusal of XPath objects */
356 void *cache;
357
358 /* Resource limits */
359 unsigned long opLimit;
360 unsigned long opCount;
361 int depth;
362};
363
364/*
365 * The structure of a compiled expression form is not public.
366 */
367
368typedef struct _xmlXPathCompExpr xmlXPathCompExpr;
369typedef xmlXPathCompExpr *xmlXPathCompExprPtr;
370
371/**
372 * xmlXPathParserContext:
373 *
374 * An XPath parser context. It contains pure parsing information,
375 * an xmlXPathContext, and the stack of objects.
376 */
377struct _xmlXPathParserContext {
378 const xmlChar *cur; /* the current char being parsed */
379 const xmlChar *base; /* the full expression */
380
381 int error; /* error code */
382
383 xmlXPathContextPtr context; /* the evaluation context */
384 xmlXPathObjectPtr value; /* the current value */
385 int valueNr; /* number of values stacked */
386 int valueMax; /* max number of values stacked */
387 xmlXPathObjectPtr *valueTab; /* stack of values */
388
389 xmlXPathCompExprPtr comp; /* the precompiled expression */
390 int xptr; /* it this an XPointer expression */
391 xmlNodePtr ancestor; /* used for walking preceding axis */
392
393 int valueFrame; /* used to limit Pop on the stack */
394};
395
396/************************************************************************
397 * *
398 * Public API *
399 * *
400 ************************************************************************/
401
402/**
403 * Objects and Nodesets handling
404 */
405
406XMLPUBVAR double xmlXPathNAN;
407XMLPUBVAR double xmlXPathPINF;
408XMLPUBVAR double xmlXPathNINF;
409
410/* These macros may later turn into functions */
411/**
412 * xmlXPathNodeSetGetLength:
413 * @ns: a node-set
414 *
415 * Implement a functionality similar to the DOM NodeList.length.
416 *
417 * Returns the number of nodes in the node-set.
418 */
419#define xmlXPathNodeSetGetLength(ns) ((ns) ? (ns)->nodeNr : 0)
420/**
421 * xmlXPathNodeSetItem:
422 * @ns: a node-set
423 * @index: index of a node in the set
424 *
425 * Implements a functionality similar to the DOM NodeList.item().
426 *
427 * Returns the xmlNodePtr at the given @index in @ns or NULL if
428 * @index is out of range (0 to length-1)
429 */
430#define xmlXPathNodeSetItem(ns, index) \
431 ((((ns) != NULL) && \
432 ((index) >= 0) && ((index) < (ns)->nodeNr)) ? \
433 (ns)->nodeTab[(index)] \
434 : NULL)
435/**
436 * xmlXPathNodeSetIsEmpty:
437 * @ns: a node-set
438 *
439 * Checks whether @ns is empty or not.
440 *
441 * Returns %TRUE if @ns is an empty node-set.
442 */
443#define xmlXPathNodeSetIsEmpty(ns) \
444 (((ns) == NULL) || ((ns)->nodeNr == 0) || ((ns)->nodeTab == NULL))
445
446
447XMLPUBFUN void XMLCALL
448 xmlXPathFreeObject (xmlXPathObjectPtr obj);
449XMLPUBFUN xmlNodeSetPtr XMLCALL
450 xmlXPathNodeSetCreate (xmlNodePtr val);
451XMLPUBFUN void XMLCALL
452 xmlXPathFreeNodeSetList (xmlXPathObjectPtr obj);
453XMLPUBFUN void XMLCALL
454 xmlXPathFreeNodeSet (xmlNodeSetPtr obj);
455XMLPUBFUN xmlXPathObjectPtr XMLCALL
456 xmlXPathObjectCopy (xmlXPathObjectPtr val);
457XMLPUBFUN int XMLCALL
458 xmlXPathCmpNodes (xmlNodePtr node1,
459 xmlNodePtr node2);
460/**
461 * Conversion functions to basic types.
462 */
463XMLPUBFUN int XMLCALL
464 xmlXPathCastNumberToBoolean (double val);
465XMLPUBFUN int XMLCALL
466 xmlXPathCastStringToBoolean (const xmlChar * val);
467XMLPUBFUN int XMLCALL
468 xmlXPathCastNodeSetToBoolean(xmlNodeSetPtr ns);
469XMLPUBFUN int XMLCALL
470 xmlXPathCastToBoolean (xmlXPathObjectPtr val);
471
472XMLPUBFUN double XMLCALL
473 xmlXPathCastBooleanToNumber (int val);
474XMLPUBFUN double XMLCALL
475 xmlXPathCastStringToNumber (const xmlChar * val);
476XMLPUBFUN double XMLCALL
477 xmlXPathCastNodeToNumber (xmlNodePtr node);
478XMLPUBFUN double XMLCALL
479 xmlXPathCastNodeSetToNumber (xmlNodeSetPtr ns);
480XMLPUBFUN double XMLCALL
481 xmlXPathCastToNumber (xmlXPathObjectPtr val);
482
483XMLPUBFUN xmlChar * XMLCALL
484 xmlXPathCastBooleanToString (int val);
485XMLPUBFUN xmlChar * XMLCALL
486 xmlXPathCastNumberToString (double val);
487XMLPUBFUN xmlChar * XMLCALL
488 xmlXPathCastNodeToString (xmlNodePtr node);
489XMLPUBFUN xmlChar * XMLCALL
490 xmlXPathCastNodeSetToString (xmlNodeSetPtr ns);
491XMLPUBFUN xmlChar * XMLCALL
492 xmlXPathCastToString (xmlXPathObjectPtr val);
493
494XMLPUBFUN xmlXPathObjectPtr XMLCALL
495 xmlXPathConvertBoolean (xmlXPathObjectPtr val);
496XMLPUBFUN xmlXPathObjectPtr XMLCALL
497 xmlXPathConvertNumber (xmlXPathObjectPtr val);
498XMLPUBFUN xmlXPathObjectPtr XMLCALL
499 xmlXPathConvertString (xmlXPathObjectPtr val);
500
501/**
502 * Context handling.
503 */
504XMLPUBFUN xmlXPathContextPtr XMLCALL
505 xmlXPathNewContext (xmlDocPtr doc);
506XMLPUBFUN void XMLCALL
507 xmlXPathFreeContext (xmlXPathContextPtr ctxt);
508XMLPUBFUN int XMLCALL
509 xmlXPathContextSetCache(xmlXPathContextPtr ctxt,
510 int active,
511 int value,
512 int options);
513/**
514 * Evaluation functions.
515 */
516XMLPUBFUN long XMLCALL
517 xmlXPathOrderDocElems (xmlDocPtr doc);
518XMLPUBFUN int XMLCALL
519 xmlXPathSetContextNode (xmlNodePtr node,
520 xmlXPathContextPtr ctx);
521XMLPUBFUN xmlXPathObjectPtr XMLCALL
522 xmlXPathNodeEval (xmlNodePtr node,
523 const xmlChar *str,
524 xmlXPathContextPtr ctx);
525XMLPUBFUN xmlXPathObjectPtr XMLCALL
526 xmlXPathEval (const xmlChar *str,
527 xmlXPathContextPtr ctx);
528XMLPUBFUN xmlXPathObjectPtr XMLCALL
529 xmlXPathEvalExpression (const xmlChar *str,
530 xmlXPathContextPtr ctxt);
531XMLPUBFUN int XMLCALL
532 xmlXPathEvalPredicate (xmlXPathContextPtr ctxt,
533 xmlXPathObjectPtr res);
534/**
535 * Separate compilation/evaluation entry points.
536 */
537XMLPUBFUN xmlXPathCompExprPtr XMLCALL
538 xmlXPathCompile (const xmlChar *str);
539XMLPUBFUN xmlXPathCompExprPtr XMLCALL
540 xmlXPathCtxtCompile (xmlXPathContextPtr ctxt,
541 const xmlChar *str);
542XMLPUBFUN xmlXPathObjectPtr XMLCALL
543 xmlXPathCompiledEval (xmlXPathCompExprPtr comp,
544 xmlXPathContextPtr ctx);
545XMLPUBFUN int XMLCALL
546 xmlXPathCompiledEvalToBoolean(xmlXPathCompExprPtr comp,
547 xmlXPathContextPtr ctxt);
548XMLPUBFUN void XMLCALL
549 xmlXPathFreeCompExpr (xmlXPathCompExprPtr comp);
550#endif /* LIBXML_XPATH_ENABLED */
551#if defined(LIBXML_XPATH_ENABLED) || defined(LIBXML_SCHEMAS_ENABLED)
552XMLPUBFUN void XMLCALL
553 xmlXPathInit (void);
554XMLPUBFUN int XMLCALL
555 xmlXPathIsNaN (double val);
556XMLPUBFUN int XMLCALL
557 xmlXPathIsInf (double val);
558
559#ifdef __cplusplus
560}
561#endif
562
563#endif /* LIBXML_XPATH_ENABLED or LIBXML_SCHEMAS_ENABLED*/
564#endif /* ! __XML_XPATH_H__ */
565

source code of include/libxml2/libxml/xpath.h