xpath.h revision 1b7783879f7122564e209c7124301e886079f393 
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} xmlXPathError;
73
74/*
75 * A node-set (an unordered collection of nodes without duplicates).
76 */
77typedef struct _xmlNodeSet xmlNodeSet;
78typedef xmlNodeSet *xmlNodeSetPtr;
79struct _xmlNodeSet {
80    int nodeNr;			/* number of nodes in the set */
81    int nodeMax;		/* size of the array as allocated */
82    xmlNodePtr *nodeTab;	/* array of nodes in no particular order */
83    /* @@ with_ns to check wether namespace nodes should be looked at @@ */
84};
85
86/*
87 * An expression is evaluated to yield an object, which
88 * has one of the following four basic types:
89 *   - node-set
90 *   - boolean
91 *   - number
92 *   - string
93 *
94 * @@ XPointer will add more types !
95 */
96
97typedef enum {
98    XPATH_UNDEFINED = 0,
99    XPATH_NODESET = 1,
100    XPATH_BOOLEAN = 2,
101    XPATH_NUMBER = 3,
102    XPATH_STRING = 4,
103    XPATH_POINT = 5,
104    XPATH_RANGE = 6,
105    XPATH_LOCATIONSET = 7,
106    XPATH_USERS = 8,
107    XPATH_XSLT_TREE = 9  /* An XSLT value tree, non modifiable */
108} xmlXPathObjectType;
109
110typedef struct _xmlXPathObject xmlXPathObject;
111typedef xmlXPathObject *xmlXPathObjectPtr;
112struct _xmlXPathObject {
113    xmlXPathObjectType type;
114    xmlNodeSetPtr nodesetval;
115    int boolval;
116    double floatval;
117    xmlChar *stringval;
118    void *user;
119    int index;
120    void *user2;
121    int index2;
122};
123
124/**
125 * xmlXPathConvertFunc:
126 * @obj:  an XPath object
127 * @type:  the number of the target type
128 *
129 * A conversion function is associated to a type and used to cast
130 * the new type to primitive values.
131 *
132 * Returns -1 in case of error, 0 otherwise
133 */
134typedef int (*xmlXPathConvertFunc) (xmlXPathObjectPtr obj, int type);
135
136/*
137 * Extra type: a name and a conversion function.
138 */
139
140typedef struct _xmlXPathType xmlXPathType;
141typedef xmlXPathType *xmlXPathTypePtr;
142struct _xmlXPathType {
143    const xmlChar         *name;		/* the type name */
144    xmlXPathConvertFunc func;		/* the conversion function */
145};
146
147/*
148 * Extra variable: a name and a value.
149 */
150
151typedef struct _xmlXPathVariable xmlXPathVariable;
152typedef xmlXPathVariable *xmlXPathVariablePtr;
153struct _xmlXPathVariable {
154    const xmlChar       *name;		/* the variable name */
155    xmlXPathObjectPtr value;		/* the value */
156};
157
158/**
159 * xmlXPathEvalFunc:
160 * @ctxt: an XPath parser context
161 * @nargs: the number of arguments passed to the function
162 *
163 * An XPath evaluation function, the parameters are on the XPath context stack.
164 */
165
166typedef void (*xmlXPathEvalFunc)(xmlXPathParserContextPtr ctxt,
167	                         int nargs);
168
169/*
170 * Extra function: a name and a evaluation function.
171 */
172
173typedef struct _xmlXPathFunct xmlXPathFunct;
174typedef xmlXPathFunct *xmlXPathFuncPtr;
175struct _xmlXPathFunct {
176    const xmlChar      *name;		/* the function name */
177    xmlXPathEvalFunc func;		/* the evaluation function */
178};
179
180/**
181 * xmlXPathAxisFunc:
182 * @ctxt:  the XPath interpreter context
183 * @cur:  the previous node being explored on that axis
184 *
185 * An axis traversal function. To traverse an axis, the engine calls
186 * the first time with cur == NULL and repeat until the function returns
187 * NULL indicating the end of the axis traversal.
188 *
189 * Returns the next node in that axis or NULL if at the end of the axis.
190 */
191
192typedef xmlXPathObjectPtr (*xmlXPathAxisFunc) (xmlXPathParserContextPtr ctxt,
193				 xmlXPathObjectPtr cur);
194
195/*
196 * Extra axis: a name and an axis function.
197 */
198
199typedef struct _xmlXPathAxis xmlXPathAxis;
200typedef xmlXPathAxis *xmlXPathAxisPtr;
201struct _xmlXPathAxis {
202    const xmlChar      *name;		/* the axis name */
203    xmlXPathAxisFunc func;		/* the search function */
204};
205
206/**
207 * xmlXPathFunction:
208 * @ctxt:  the XPath interprestation context
209 * @nargs:  the number of arguments
210 *
211 * An XPath function.
212 * The arguments (if any) are popped out from the context stack
213 * and the result is pushed on the stack.
214 */
215
216typedef void (*xmlXPathFunction) (xmlXPathParserContextPtr ctxt, int nargs);
217
218/*
219 * Function and Variable Lookup.
220 */
221
222/**
223 * xmlXPathVariableLookupFunc:
224 * @ctxt:  an XPath context
225 * @name:  name of the variable
226 * @ns_uri:  the namespace name hosting this variable
227 *
228 * Prototype for callbacks used to plug variable lookup in the XPath
229 * engine.
230 *
231 * Returns the XPath object value or NULL if not found.
232 */
233typedef xmlXPathObjectPtr (*xmlXPathVariableLookupFunc) (void *ctxt,
234                                         const xmlChar *name,
235                                         const xmlChar *ns_uri);
236
237/**
238 * xmlXPathFuncLookupFunc:
239 * @ctxt:  an XPath context
240 * @name:  name of the function
241 * @ns_uri:  the namespace name hosting this function
242 *
243 * Prototype for callbacks used to plug function lookup in the XPath
244 * engine.
245 *
246 * Returns the XPath function or NULL if not found.
247 */
248typedef xmlXPathFunction (*xmlXPathFuncLookupFunc) (void *ctxt,
249					 const xmlChar *name,
250					 const xmlChar *ns_uri);
251
252/**
253 * xmlXPathFlags:
254 * Flags for XPath engine compilation and runtime
255 */
256/**
257 * XML_XPATH_CHECKNS:
258 *
259 * check namespaces at compilation
260 */
261#define XML_XPATH_CHECKNS (1<<0)
262/**
263 * XML_XPATH_NOVAR:
264 *
265 * forbid variables in expression
266 */
267#define XML_XPATH_NOVAR	  (1<<1)
268
269/**
270 * xmlXPathContext:
271 *
272 * Expression evaluation occurs with respect to a context.
273 * he context consists of:
274 *    - a node (the context node)
275 *    - a node list (the context node list)
276 *    - a set of variable bindings
277 *    - a function library
278 *    - the set of namespace declarations in scope for the expression
279 * Following the switch to hash tables, this need to be trimmed up at
280 * the next binary incompatible release.
281 */
282
283struct _xmlXPathContext {
284    xmlDocPtr doc;			/* The current document */
285    xmlNodePtr node;			/* The current node */
286
287    int nb_variables_unused;		/* unused (hash table) */
288    int max_variables_unused;		/* unused (hash table) */
289    xmlHashTablePtr varHash;		/* Hash table of defined variables */
290
291    int nb_types;			/* number of defined types */
292    int max_types;			/* max number of types */
293    xmlXPathTypePtr types;		/* Array of defined types */
294
295    int nb_funcs_unused;		/* unused (hash table) */
296    int max_funcs_unused;		/* unused (hash table) */
297    xmlHashTablePtr funcHash;		/* Hash table of defined funcs */
298
299    int nb_axis;			/* number of defined axis */
300    int max_axis;			/* max number of axis */
301    xmlXPathAxisPtr axis;		/* Array of defined axis */
302
303    /* the namespace nodes of the context node */
304    xmlNsPtr *namespaces;		/* Array of namespaces */
305    int nsNr;				/* number of namespace in scope */
306    void *user;				/* function to free */
307
308    /* extra variables */
309    int contextSize;			/* the context size */
310    int proximityPosition;		/* the proximity position */
311
312    /* extra stuff for XPointer */
313    int xptr;				/* is this an XPointer context? */
314    xmlNodePtr here;			/* for here() */
315    xmlNodePtr origin;			/* for origin() */
316
317    /* the set of namespace declarations in scope for the expression */
318    xmlHashTablePtr nsHash;		/* The namespaces hash table */
319    xmlXPathVariableLookupFunc varLookupFunc;/* variable lookup func */
320    void *varLookupData;		/* variable lookup data */
321
322    /* Possibility to link in an extra item */
323    void *extra;                        /* needed for XSLT */
324
325    /* The function name and URI when calling a function */
326    const xmlChar *function;
327    const xmlChar *functionURI;
328
329    /* function lookup function and data */
330    xmlXPathFuncLookupFunc funcLookupFunc;/* function lookup func */
331    void *funcLookupData;		/* function lookup data */
332
333    /* temporary namespace lists kept for walking the namespace axis */
334    xmlNsPtr *tmpNsList;		/* Array of namespaces */
335    int tmpNsNr;			/* number of namespaces in scope */
336
337    /* error reporting mechanism */
338    void *userData;                     /* user specific data block */
339    xmlStructuredErrorFunc error;       /* the callback in case of errors */
340    xmlError lastError;			/* the last error */
341    xmlNodePtr debugNode;		/* the source node XSLT */
342
343    /* dictionary */
344    xmlDictPtr dict;			/* dictionary if any */
345
346    int flags;				/* flags to control compilation */
347
348    /* Cache for reusal of XPath objects */
349    void *cache;
350};
351
352/*
353 * The structure of a compiled expression form is not public.
354 */
355
356typedef struct _xmlXPathCompExpr xmlXPathCompExpr;
357typedef xmlXPathCompExpr *xmlXPathCompExprPtr;
358
359/**
360 * xmlXPathParserContext:
361 *
362 * An XPath parser context. It contains pure parsing informations,
363 * an xmlXPathContext, and the stack of objects.
364 */
365struct _xmlXPathParserContext {
366    const xmlChar *cur;			/* the current char being parsed */
367    const xmlChar *base;			/* the full expression */
368
369    int error;				/* error code */
370
371    xmlXPathContextPtr  context;	/* the evaluation context */
372    xmlXPathObjectPtr     value;	/* the current value */
373    int                 valueNr;	/* number of values stacked */
374    int                valueMax;	/* max number of values stacked */
375    xmlXPathObjectPtr *valueTab;	/* stack of values */
376
377    xmlXPathCompExprPtr comp;		/* the precompiled expression */
378    int xptr;				/* it this an XPointer expression */
379    xmlNodePtr         ancestor;	/* used for walking preceding axis */
380};
381
382/************************************************************************
383 *									*
384 *			Public API					*
385 *									*
386 ************************************************************************/
387
388/**
389 * Objects and Nodesets handling
390 */
391
392XMLPUBVAR double xmlXPathNAN;
393XMLPUBVAR double xmlXPathPINF;
394XMLPUBVAR double xmlXPathNINF;
395
396/* These macros may later turn into functions */
397/**
398 * xmlXPathNodeSetGetLength:
399 * @ns:  a node-set
400 *
401 * Implement a functionality similar to the DOM NodeList.length.
402 *
403 * Returns the number of nodes in the node-set.
404 */
405#define xmlXPathNodeSetGetLength(ns) ((ns) ? (ns)->nodeNr : 0)
406/**
407 * xmlXPathNodeSetItem:
408 * @ns:  a node-set
409 * @index:  index of a node in the set
410 *
411 * Implements a functionality similar to the DOM NodeList.item().
412 *
413 * Returns the xmlNodePtr at the given @index in @ns or NULL if
414 *         @index is out of range (0 to length-1)
415 */
416#define xmlXPathNodeSetItem(ns, index)				\
417		((((ns) != NULL) && 				\
418		  ((index) >= 0) && ((index) < (ns)->nodeNr)) ?	\
419		 (ns)->nodeTab[(index)]				\
420		 : NULL)
421/**
422 * xmlXPathNodeSetIsEmpty:
423 * @ns: a node-set
424 *
425 * Checks whether @ns is empty or not.
426 *
427 * Returns %TRUE if @ns is an empty node-set.
428 */
429#define xmlXPathNodeSetIsEmpty(ns)                                      \
430    (((ns) == NULL) || ((ns)->nodeNr == 0) || ((ns)->nodeTab == NULL))
431
432
433XMLPUBFUN void XMLCALL
434		    xmlXPathFreeObject		(xmlXPathObjectPtr obj);
435XMLPUBFUN xmlNodeSetPtr XMLCALL
436		    xmlXPathNodeSetCreate	(xmlNodePtr val);
437XMLPUBFUN void XMLCALL
438		    xmlXPathFreeNodeSetList	(xmlXPathObjectPtr obj);
439XMLPUBFUN void XMLCALL
440		    xmlXPathFreeNodeSet		(xmlNodeSetPtr obj);
441XMLPUBFUN xmlXPathObjectPtr XMLCALL
442		    xmlXPathObjectCopy		(xmlXPathObjectPtr val);
443XMLPUBFUN int XMLCALL
444		    xmlXPathCmpNodes		(xmlNodePtr node1,
445						 xmlNodePtr node2);
446/**
447 * Conversion functions to basic types.
448 */
449XMLPUBFUN int XMLCALL
450		    xmlXPathCastNumberToBoolean	(double val);
451XMLPUBFUN int XMLCALL
452		    xmlXPathCastStringToBoolean	(const xmlChar * val);
453XMLPUBFUN int XMLCALL
454		    xmlXPathCastNodeSetToBoolean(xmlNodeSetPtr ns);
455XMLPUBFUN int XMLCALL
456		    xmlXPathCastToBoolean	(xmlXPathObjectPtr val);
457
458XMLPUBFUN double XMLCALL
459		    xmlXPathCastBooleanToNumber	(int val);
460XMLPUBFUN double XMLCALL
461		    xmlXPathCastStringToNumber	(const xmlChar * val);
462XMLPUBFUN double XMLCALL
463		    xmlXPathCastNodeToNumber	(xmlNodePtr node);
464XMLPUBFUN double XMLCALL
465		    xmlXPathCastNodeSetToNumber	(xmlNodeSetPtr ns);
466XMLPUBFUN double XMLCALL
467		    xmlXPathCastToNumber	(xmlXPathObjectPtr val);
468
469XMLPUBFUN xmlChar * XMLCALL
470		    xmlXPathCastBooleanToString	(int val);
471XMLPUBFUN xmlChar * XMLCALL
472		    xmlXPathCastNumberToString	(double val);
473XMLPUBFUN xmlChar * XMLCALL
474		    xmlXPathCastNodeToString	(xmlNodePtr node);
475XMLPUBFUN xmlChar * XMLCALL
476		    xmlXPathCastNodeSetToString	(xmlNodeSetPtr ns);
477XMLPUBFUN xmlChar * XMLCALL
478		    xmlXPathCastToString	(xmlXPathObjectPtr val);
479
480XMLPUBFUN xmlXPathObjectPtr XMLCALL
481		    xmlXPathConvertBoolean	(xmlXPathObjectPtr val);
482XMLPUBFUN xmlXPathObjectPtr XMLCALL
483		    xmlXPathConvertNumber	(xmlXPathObjectPtr val);
484XMLPUBFUN xmlXPathObjectPtr XMLCALL
485		    xmlXPathConvertString	(xmlXPathObjectPtr val);
486
487/**
488 * Context handling.
489 */
490XMLPUBFUN xmlXPathContextPtr XMLCALL
491		    xmlXPathNewContext		(xmlDocPtr doc);
492XMLPUBFUN void XMLCALL
493		    xmlXPathFreeContext		(xmlXPathContextPtr ctxt);
494XMLPUBFUN int XMLCALL
495		    xmlXPathContextSetCache(xmlXPathContextPtr ctxt,
496				            int active,
497					    int value,
498					    int options);
499/**
500 * Evaluation functions.
501 */
502XMLPUBFUN long XMLCALL
503		    xmlXPathOrderDocElems	(xmlDocPtr doc);
504XMLPUBFUN xmlXPathObjectPtr XMLCALL
505		    xmlXPathEval		(const xmlChar *str,
506						 xmlXPathContextPtr ctx);
507XMLPUBFUN xmlXPathObjectPtr XMLCALL
508		    xmlXPathEvalExpression	(const xmlChar *str,
509						 xmlXPathContextPtr ctxt);
510XMLPUBFUN int XMLCALL
511		    xmlXPathEvalPredicate	(xmlXPathContextPtr ctxt,
512						 xmlXPathObjectPtr res);
513/**
514 * Separate compilation/evaluation entry points.
515 */
516XMLPUBFUN xmlXPathCompExprPtr XMLCALL
517		    xmlXPathCompile		(const xmlChar *str);
518XMLPUBFUN xmlXPathCompExprPtr XMLCALL
519		    xmlXPathCtxtCompile		(xmlXPathContextPtr ctxt,
520		    				 const xmlChar *str);
521XMLPUBFUN xmlXPathObjectPtr XMLCALL
522		    xmlXPathCompiledEval	(xmlXPathCompExprPtr comp,
523						 xmlXPathContextPtr ctx);
524XMLPUBFUN int XMLCALL
525		    xmlXPathCompiledEvalToBoolean(xmlXPathCompExprPtr comp,
526						 xmlXPathContextPtr ctxt);
527XMLPUBFUN void XMLCALL
528		    xmlXPathFreeCompExpr	(xmlXPathCompExprPtr comp);
529#endif /* LIBXML_XPATH_ENABLED */
530#if defined(LIBXML_XPATH_ENABLED) || defined(LIBXML_SCHEMAS_ENABLED)
531XMLPUBFUN void XMLCALL
532		    xmlXPathInit		(void);
533XMLPUBFUN int XMLCALL
534		xmlXPathIsNaN	(double val);
535XMLPUBFUN int XMLCALL
536		xmlXPathIsInf	(double val);
537
538#ifdef __cplusplus
539}
540#endif
541
542#endif /* LIBXML_XPATH_ENABLED or LIBXML_SCHEMAS_ENABLED*/
543#endif /* ! __XML_XPATH_H__ */
544