* Summary: XML Path Language implementation
* Description: API for the XML Path Language implementation
* XML Path Language implementation
* XPath is a language for addressing parts of an XML document,
* designed to be used by both XSLT and XPointer
* http://www.w3.org/TR/xpath
* W3C Recommendation 16 November 1999
* http://www.w3.org/TR/1999/REC-xpath-19991116
* Copy: See Copyright for the status of this software.
* Author: Daniel Veillard
#include <libxml/xmlversion.h>
#ifdef LIBXML_XPATH_ENABLED
#include <libxml/xmlerror.h>
#endif /* LIBXML_XPATH_ENABLED */
#if defined(LIBXML_XPATH_ENABLED) || defined(LIBXML_SCHEMAS_ENABLED)
#endif /* LIBXML_XPATH_ENABLED or LIBXML_SCHEMAS_ENABLED */
#ifdef LIBXML_XPATH_ENABLED
typedef struct _xmlXPathContext xmlXPathContext;
typedef xmlXPathContext *xmlXPathContextPtr;
typedef struct _xmlXPathParserContext xmlXPathParserContext;
typedef xmlXPathParserContext *xmlXPathParserContextPtr;
* The set of XPath error codes.
XPATH_UNFINISHED_LITERAL_ERROR,
XPATH_START_LITERAL_ERROR,
XPATH_VARIABLE_REF_ERROR,
XPATH_UNDEF_VARIABLE_ERROR,
XPATH_INVALID_PREDICATE_ERROR,
XPATH_UNKNOWN_FUNC_ERROR,
XPATH_INVALID_CTXT_POSITION,
XPATH_UNDEF_PREFIX_ERROR,
XPATH_INVALID_CHAR_ERROR,
XPATH_FORBID_VARIABLE_ERROR
* A node-set (an unordered collection of nodes without duplicates).
typedef struct _xmlNodeSet xmlNodeSet;
typedef xmlNodeSet *xmlNodeSetPtr;
int nodeNr; /* number of nodes in the set */
int nodeMax; /* size of the array as allocated */
xmlNodePtr *nodeTab; /* array of nodes in no particular order */
/* @@ with_ns to check wether namespace nodes should be looked at @@ */
* An expression is evaluated to yield an object, which
* has one of the following four basic types:
* @@ XPointer will add more types !
XPATH_XSLT_TREE = 9 /* An XSLT value tree, non modifiable */
typedef struct _xmlXPathObject xmlXPathObject;
typedef xmlXPathObject *xmlXPathObjectPtr;
xmlNodeSetPtr nodesetval;
* @type: the number of the target type
* A conversion function is associated to a type and used to cast
* the new type to primitive values.
* Returns -1 in case of error, 0 otherwise
typedef int (*xmlXPathConvertFunc) (xmlXPathObjectPtr obj, int type);
* Extra type: a name and a conversion function.
typedef struct _xmlXPathType xmlXPathType;
typedef xmlXPathType *xmlXPathTypePtr;
const xmlChar *name; /* the type name */
xmlXPathConvertFunc func; /* the conversion function */
* Extra variable: a name and a value.
typedef struct _xmlXPathVariable xmlXPathVariable;
typedef xmlXPathVariable *xmlXPathVariablePtr;
struct _xmlXPathVariable {
const xmlChar *name; /* the variable name */
xmlXPathObjectPtr value; /* the value */
* @ctxt: an XPath parser context
* @nargs: the number of arguments passed to the function
* An XPath evaluation function, the parameters are on the XPath context stack.
typedef void (*xmlXPathEvalFunc)(xmlXPathParserContextPtr ctxt,
* Extra function: a name and a evaluation function.
typedef struct _xmlXPathFunct xmlXPathFunct;
typedef xmlXPathFunct *xmlXPathFuncPtr;
const xmlChar *name; /* the function name */
xmlXPathEvalFunc func; /* the evaluation function */
* @ctxt: the XPath interpreter context
* @cur: the previous node being explored on that axis
* An axis traversal function. To traverse an axis, the engine calls
* the first time with cur == NULL and repeat until the function returns
* NULL indicating the end of the axis traversal.
* Returns the next node in that axis or NULL if at the end of the axis.
typedef xmlXPathObjectPtr (*xmlXPathAxisFunc) (xmlXPathParserContextPtr ctxt,
* Extra axis: a name and an axis function.
typedef struct _xmlXPathAxis xmlXPathAxis;
typedef xmlXPathAxis *xmlXPathAxisPtr;
const xmlChar *name; /* the axis name */
xmlXPathAxisFunc func; /* the search function */
* @ctxt: the XPath interprestation context
* @nargs: the number of arguments
* The arguments (if any) are popped out from the context stack
* and the result is pushed on the stack.
typedef void (*xmlXPathFunction) (xmlXPathParserContextPtr ctxt, int nargs);
* Function and Variable Lookup.
* xmlXPathVariableLookupFunc:
* @ctxt: an XPath context
* @name: name of the variable
* @ns_uri: the namespace name hosting this variable
* Prototype for callbacks used to plug variable lookup in the XPath
* Returns the XPath object value or NULL if not found.
typedef xmlXPathObjectPtr (*xmlXPathVariableLookupFunc) (void *ctxt,
* xmlXPathFuncLookupFunc:
* @ctxt: an XPath context
* @name: name of the function
* @ns_uri: the namespace name hosting this function
* Prototype for callbacks used to plug function lookup in the XPath
* Returns the XPath function or NULL if not found.
typedef xmlXPathFunction (*xmlXPathFuncLookupFunc) (void *ctxt,
* Flags for XPath engine compilation and runtime
* check namespaces at compilation
#define XML_XPATH_CHECKNS (1<<0)
* forbid variables in expression
#define XML_XPATH_NOVAR (1<<1)
* Expression evaluation occurs with respect to a context.
* he context consists of:
* - a node (the context node)
* - a node list (the context node list)
* - a set of variable bindings
* - the set of namespace declarations in scope for the expression
* Following the switch to hash tables, this need to be trimmed up at
* the next binary incompatible release.
* The node may be modified when the context is passed to libxml2
* for an XPath evaluation so you may need to initialize it again
struct _xmlXPathContext {
xmlDocPtr doc; /* The current document */
xmlNodePtr node; /* The current node */
int nb_variables_unused; /* unused (hash table) */
int max_variables_unused; /* unused (hash table) */
xmlHashTablePtr varHash; /* Hash table of defined variables */
int nb_types; /* number of defined types */
int max_types; /* max number of types */
xmlXPathTypePtr types; /* Array of defined types */
int nb_funcs_unused; /* unused (hash table) */
int max_funcs_unused; /* unused (hash table) */
xmlHashTablePtr funcHash; /* Hash table of defined funcs */
int nb_axis; /* number of defined axis */
int max_axis; /* max number of axis */
xmlXPathAxisPtr axis; /* Array of defined axis */
/* the namespace nodes of the context node */
xmlNsPtr *namespaces; /* Array of namespaces */
int nsNr; /* number of namespace in scope */
void *user; /* function to free */
int contextSize; /* the context size */
int proximityPosition; /* the proximity position */
/* extra stuff for XPointer */
int xptr; /* is this an XPointer context? */
xmlNodePtr here; /* for here() */
xmlNodePtr origin; /* for origin() */
/* the set of namespace declarations in scope for the expression */
xmlHashTablePtr nsHash; /* The namespaces hash table */
xmlXPathVariableLookupFunc varLookupFunc;/* variable lookup func */
void *varLookupData; /* variable lookup data */
/* Possibility to link in an extra item */
void *extra; /* needed for XSLT */
/* The function name and URI when calling a function */
const xmlChar *functionURI;
/* function lookup function and data */
xmlXPathFuncLookupFunc funcLookupFunc;/* function lookup func */
void *funcLookupData; /* function lookup data */
/* temporary namespace lists kept for walking the namespace axis */
xmlNsPtr *tmpNsList; /* Array of namespaces */
int tmpNsNr; /* number of namespaces in scope */
/* error reporting mechanism */
void *userData; /* user specific data block */
xmlStructuredErrorFunc error; /* the callback in case of errors */
xmlError lastError; /* the last error */
xmlNodePtr debugNode; /* the source node XSLT */
xmlDictPtr dict; /* dictionary if any */
int flags; /* flags to control compilation */
/* Cache for reusal of XPath objects */
* The structure of a compiled expression form is not public.
typedef struct _xmlXPathCompExpr xmlXPathCompExpr;
typedef xmlXPathCompExpr *xmlXPathCompExprPtr;
* An XPath parser context. It contains pure parsing informations,
* an xmlXPathContext, and the stack of objects.
struct _xmlXPathParserContext {
const xmlChar *cur; /* the current char being parsed */
const xmlChar *base; /* the full expression */
int error; /* error code */
xmlXPathContextPtr context; /* the evaluation context */
xmlXPathObjectPtr value; /* the current value */
int valueNr; /* number of values stacked */
int valueMax; /* max number of values stacked */
xmlXPathObjectPtr *valueTab; /* stack of values */
xmlXPathCompExprPtr comp; /* the precompiled expression */
int xptr; /* it this an XPointer expression */
xmlNodePtr ancestor; /* used for walking preceding axis */
int valueFrame; /* used to limit Pop on the stack */
/************************************************************************
************************************************************************/
* Objects and Nodesets handling
XMLPUBVAR double xmlXPathNAN;
XMLPUBVAR double xmlXPathPINF;
XMLPUBVAR double xmlXPathNINF;
/* These macros may later turn into functions */
* xmlXPathNodeSetGetLength:
* Implement a functionality similar to the DOM NodeList.length.
* Returns the number of nodes in the node-set.
#define xmlXPathNodeSetGetLength(ns) ((ns) ? (ns)->nodeNr : 0)
* @index: index of a node in the set
* Implements a functionality similar to the DOM NodeList.item().
* Returns the xmlNodePtr at the given @index in @ns or NULL if
* @index is out of range (0 to length-1)
#define xmlXPathNodeSetItem(ns, index) \
((index) >= 0) && ((index) < (ns)->nodeNr)) ? \
* xmlXPathNodeSetIsEmpty:
* Checks whether @ns is empty or not.
* Returns %TRUE if @ns is an empty node-set.
#define xmlXPathNodeSetIsEmpty(ns) \
(((ns) == NULL) || ((ns)->nodeNr == 0) || ((ns)->nodeTab == NULL))
xmlXPathFreeObject (xmlXPathObjectPtr obj);
XMLPUBFUN xmlNodeSetPtr XMLCALL
xmlXPathNodeSetCreate (xmlNodePtr val);
xmlXPathFreeNodeSetList (xmlXPathObjectPtr obj);
xmlXPathFreeNodeSet (xmlNodeSetPtr obj);
XMLPUBFUN xmlXPathObjectPtr XMLCALL
xmlXPathObjectCopy (xmlXPathObjectPtr val);
xmlXPathCmpNodes (xmlNodePtr node1,
* Conversion functions to basic types.
xmlXPathCastNumberToBoolean (double val);
xmlXPathCastStringToBoolean (const xmlChar * val);
xmlXPathCastNodeSetToBoolean(xmlNodeSetPtr ns);
xmlXPathCastToBoolean (xmlXPathObjectPtr val);
xmlXPathCastBooleanToNumber (int val);
xmlXPathCastStringToNumber (const xmlChar * val);
xmlXPathCastNodeToNumber (xmlNodePtr node);
xmlXPathCastNodeSetToNumber (xmlNodeSetPtr ns);
xmlXPathCastToNumber (xmlXPathObjectPtr val);
XMLPUBFUN xmlChar * XMLCALL
xmlXPathCastBooleanToString (int val);
XMLPUBFUN xmlChar * XMLCALL
xmlXPathCastNumberToString (double val);
XMLPUBFUN xmlChar * XMLCALL
xmlXPathCastNodeToString (xmlNodePtr node);
XMLPUBFUN xmlChar * XMLCALL
xmlXPathCastNodeSetToString (xmlNodeSetPtr ns);
XMLPUBFUN xmlChar * XMLCALL
xmlXPathCastToString (xmlXPathObjectPtr val);
XMLPUBFUN xmlXPathObjectPtr XMLCALL
xmlXPathConvertBoolean (xmlXPathObjectPtr val);
XMLPUBFUN xmlXPathObjectPtr XMLCALL
xmlXPathConvertNumber (xmlXPathObjectPtr val);
XMLPUBFUN xmlXPathObjectPtr XMLCALL
xmlXPathConvertString (xmlXPathObjectPtr val);
XMLPUBFUN xmlXPathContextPtr XMLCALL
xmlXPathNewContext (xmlDocPtr doc);
xmlXPathFreeContext (xmlXPathContextPtr ctxt);
