xpath.h

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/*
 * 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
 *
 * Implements
 * 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
 */

#ifndef __XML_XPATH_H__
#define __XML_XPATH_H__

#include <libxml/xmlversion.h>

#ifdef LIBXML_XPATH_ENABLED

#include <libxml/xmlerror.h>
#include <libxml/tree.h>
#include <libxml/hash.h>
#endif /* LIBXML_XPATH_ENABLED */

#if defined(LIBXML_XPATH_ENABLED) || defined(LIBXML_SCHEMAS_ENABLED)
#ifdef __cplusplus
extern "C" {
#endif
#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;

typedef enum {
    XPATH_EXPRESSION_OK = 0,
    XPATH_NUMBER_ERROR,
    XPATH_UNFINISHED_LITERAL_ERROR,
    XPATH_START_LITERAL_ERROR,
    XPATH_VARIABLE_REF_ERROR,
    XPATH_UNDEF_VARIABLE_ERROR,
    XPATH_INVALID_PREDICATE_ERROR,
    XPATH_EXPR_ERROR,
    XPATH_UNCLOSED_ERROR,
    XPATH_UNKNOWN_FUNC_ERROR,
    XPATH_INVALID_OPERAND,
    XPATH_INVALID_TYPE,
    XPATH_INVALID_ARITY,
    XPATH_INVALID_CTXT_SIZE,
    XPATH_INVALID_CTXT_POSITION,
    XPATH_MEMORY_ERROR,
    XPTR_SYNTAX_ERROR,
    XPTR_RESOURCE_ERROR,
    XPTR_SUB_RESOURCE_ERROR,
    XPATH_UNDEF_PREFIX_ERROR,
    XPATH_ENCODING_ERROR,
    XPATH_INVALID_CHAR_ERROR,
    XPATH_INVALID_CTXT
} xmlXPathError;

/*
 * A node-set (an unordered collection of nodes without duplicates).
 */
typedef struct _xmlNodeSet xmlNodeSet;
typedef xmlNodeSet *xmlNodeSetPtr;
struct _xmlNodeSet {
    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:
 *   - node-set
 *   - boolean
 *   - number
 *   - string
 *
 * @@ XPointer will add more types !
 */

typedef enum {
    XPATH_UNDEFINED = 0,
    XPATH_NODESET = 1,
    XPATH_BOOLEAN = 2,
    XPATH_NUMBER = 3,
    XPATH_STRING = 4,
    XPATH_POINT = 5,
    XPATH_RANGE = 6,
    XPATH_LOCATIONSET = 7,
    XPATH_USERS = 8,
    XPATH_XSLT_TREE = 9  /* An XSLT value tree, non modifiable */
} xmlXPathObjectType;

typedef struct _xmlXPathObject xmlXPathObject;
typedef xmlXPathObject *xmlXPathObjectPtr;
struct _xmlXPathObject {
    xmlXPathObjectType type;
    xmlNodeSetPtr nodesetval;
    int boolval;
    double floatval;
    xmlChar *stringval;
    void *user;
    int index;
    void *user2;
    int index2;
};

typedef int (*xmlXPathConvertFunc) (xmlXPathObjectPtr obj, int type);

/*
 * Extra type: a name and a conversion function.
 */

typedef struct _xmlXPathType xmlXPathType;
typedef xmlXPathType *xmlXPathTypePtr;
struct _xmlXPathType {
    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 */
};

typedef void (*xmlXPathEvalFunc)(xmlXPathParserContextPtr ctxt,
                             int nargs);

/*
 * Extra function: a name and a evaluation function.
 */

typedef struct _xmlXPathFunct xmlXPathFunct;
typedef xmlXPathFunct *xmlXPathFuncPtr;
struct _xmlXPathFunct {
    const xmlChar      *name;       /* the function name */
    xmlXPathEvalFunc func;      /* the evaluation function */
};

typedef xmlXPathObjectPtr (*xmlXPathAxisFunc) (xmlXPathParserContextPtr ctxt,
                 xmlXPathObjectPtr cur);

/*
 * Extra axis: a name and an axis function.
 */

typedef struct _xmlXPathAxis xmlXPathAxis;
typedef xmlXPathAxis *xmlXPathAxisPtr;
struct _xmlXPathAxis {
    const xmlChar      *name;       /* the axis name */
    xmlXPathAxisFunc func;      /* the search function */
};

typedef void (*xmlXPathFunction) (xmlXPathParserContextPtr ctxt, int nargs);

/*
 * Function and Variable Lookup.
 */

typedef xmlXPathObjectPtr (*xmlXPathVariableLookupFunc) (void *ctxt,
                                         const xmlChar *name,
                                         const xmlChar *ns_uri);

typedef xmlXPathFunction (*xmlXPathFuncLookupFunc) (void *ctxt,
                     const xmlChar *name,
                     const xmlChar *ns_uri);

#define XML_XPATH_CHECKNS (1<<0)

#define XML_XPATH_NOVAR   (1<<1)

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 */

    /* extra variables */
    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 *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 */

    /* dictionary */
    xmlDictPtr dict;            /* dictionary if any */

    int flags;              /* flags to control compilation */

    /* Cache for reusal of XPath objects */
    void *cache;
};

/*
 * The structure of a compiled expression form is not public.
 */

typedef struct _xmlXPathCompExpr xmlXPathCompExpr;
typedef xmlXPathCompExpr *xmlXPathCompExprPtr;

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 */
};

/************************************************************************
 *                                  *
 *          Public API                  *
 *                                  *
 ************************************************************************/

XMLPUBVAR double xmlXPathNAN;
XMLPUBVAR double xmlXPathPINF;
XMLPUBVAR double xmlXPathNINF;

/* These macros may later turn into functions */
#define xmlXPathNodeSetGetLength(ns) ((ns) ? (ns)->nodeNr : 0)

#define xmlXPathNodeSetItem(ns, index)              \
        ((((ns) != NULL) &&                 \
          ((index) >= 0) && ((index) < (ns)->nodeNr)) ? \
         (ns)->nodeTab[(index)]             \
         : NULL)

#define xmlXPathNodeSetIsEmpty(ns)                                      \
    (((ns) == NULL) || ((ns)->nodeNr == 0) || ((ns)->nodeTab == NULL))


XMLPUBFUN void XMLCALL         
            xmlXPathFreeObject      (xmlXPathObjectPtr obj);
XMLPUBFUN xmlNodeSetPtr XMLCALL    
            xmlXPathNodeSetCreate   (xmlNodePtr val);
XMLPUBFUN void XMLCALL         
            xmlXPathFreeNodeSetList (xmlXPathObjectPtr obj);
XMLPUBFUN void XMLCALL         
            xmlXPathFreeNodeSet     (xmlNodeSetPtr obj);
XMLPUBFUN xmlXPathObjectPtr XMLCALL  
            xmlXPathObjectCopy      (xmlXPathObjectPtr val);
XMLPUBFUN int XMLCALL          
            xmlXPathCmpNodes        (xmlNodePtr node1,
                         xmlNodePtr node2);
XMLPUBFUN int XMLCALL          
            xmlXPathCastNumberToBoolean (double val);
XMLPUBFUN int XMLCALL          
            xmlXPathCastStringToBoolean (const xmlChar * val);
XMLPUBFUN int XMLCALL          
            xmlXPathCastNodeSetToBoolean(xmlNodeSetPtr ns);
XMLPUBFUN int XMLCALL          
            xmlXPathCastToBoolean   (xmlXPathObjectPtr val);

XMLPUBFUN double XMLCALL           
            xmlXPathCastBooleanToNumber (int val);
XMLPUBFUN double XMLCALL           
            xmlXPathCastStringToNumber  (const xmlChar * val);
XMLPUBFUN double XMLCALL           
            xmlXPathCastNodeToNumber    (xmlNodePtr node);
XMLPUBFUN double XMLCALL           
            xmlXPathCastNodeSetToNumber (xmlNodeSetPtr ns);
XMLPUBFUN double XMLCALL           
            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);
XMLPUBFUN void XMLCALL
            xmlXPathFreeContext     (xmlXPathContextPtr ctxt);
XMLPUBFUN int XMLCALL
            xmlXPathContextSetCache(xmlXPathContextPtr ctxt,
                            int active,
                        int value,
                        int options);
XMLPUBFUN long XMLCALL               
            xmlXPathOrderDocElems   (xmlDocPtr doc);
XMLPUBFUN xmlXPathObjectPtr XMLCALL  
            xmlXPathEval        (const xmlChar *str,
                         xmlXPathContextPtr ctx);
XMLPUBFUN xmlXPathObjectPtr XMLCALL  
            xmlXPathEvalExpression  (const xmlChar *str,
                         xmlXPathContextPtr ctxt);
XMLPUBFUN int XMLCALL                
            xmlXPathEvalPredicate   (xmlXPathContextPtr ctxt,
                         xmlXPathObjectPtr res);
XMLPUBFUN xmlXPathCompExprPtr XMLCALL 
            xmlXPathCompile     (const xmlChar *str);
XMLPUBFUN xmlXPathCompExprPtr XMLCALL 
            xmlXPathCtxtCompile     (xmlXPathContextPtr ctxt,
                             const xmlChar *str);
XMLPUBFUN xmlXPathObjectPtr XMLCALL   
            xmlXPathCompiledEval    (xmlXPathCompExprPtr comp,
                         xmlXPathContextPtr ctx);
XMLPUBFUN int XMLCALL   
            xmlXPathCompiledEvalToBoolean(xmlXPathCompExprPtr comp,
                         xmlXPathContextPtr ctxt);
XMLPUBFUN void XMLCALL                
            xmlXPathFreeCompExpr    (xmlXPathCompExprPtr comp);
#endif /* LIBXML_XPATH_ENABLED */
#if defined(LIBXML_XPATH_ENABLED) || defined(LIBXML_SCHEMAS_ENABLED)
XMLPUBFUN void XMLCALL         
            xmlXPathInit        (void);
XMLPUBFUN int XMLCALL
        xmlXPathIsNaN   (double val);
XMLPUBFUN int XMLCALL
        xmlXPathIsInf   (double val);

#ifdef __cplusplus
}
#endif

#endif /* LIBXML_XPATH_ENABLED or LIBXML_SCHEMAS_ENABLED*/
#endif /* ! __XML_XPATH_H__ */