xpathinternals.h

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/*
 * Summary: internal interfaces for XML Path Language implementation
 * Description: internal interfaces for XML Path Language implementation
 *              used to build new modules on top of XPath like XPointer and
 *              XSLT
 *
 * Copy: See Copyright for the status of this software.
 *
 * Author: Daniel Veillard
 */

#ifndef __XML_XPATH_INTERNALS_H__
#define __XML_XPATH_INTERNALS_H__

#include <libxml/xmlversion.h>
#include <libxml/xpath.h>

#ifdef LIBXML_XPATH_ENABLED

#ifdef __cplusplus
extern "C" {
#endif

/************************************************************************
 *									*
 *			Helpers						*
 *									*
 ************************************************************************/

/*
 * Many of these macros may later turn into functions. They
 * shouldn't be used in #ifdef's preprocessor instructions.
 */
/**
 * xmlXPathSetError:
 * @ctxt:  an XPath parser context
 * @err:  an xmlXPathError code
 *
 * Raises an error.
 */
#define xmlXPathSetError(ctxt, err)					\
    { xmlXPatherror((ctxt), __FILE__, __LINE__, (err));			\
      if ((ctxt) != NULL) (ctxt)->error = (err); }

/**
 * xmlXPathSetArityError:
 * @ctxt:  an XPath parser context
 *
 * Raises an XPATH_INVALID_ARITY error.
 */
#define xmlXPathSetArityError(ctxt)					\
    xmlXPathSetError((ctxt), XPATH_INVALID_ARITY)

/**
 * xmlXPathSetTypeError:
 * @ctxt:  an XPath parser context
 *
 * Raises an XPATH_INVALID_TYPE error.
 */
#define xmlXPathSetTypeError(ctxt)					\
    xmlXPathSetError((ctxt), XPATH_INVALID_TYPE)

/**
 * xmlXPathGetError:
 * @ctxt:  an XPath parser context
 *
 * Get the error code of an XPath context.
 *
 * Returns the context error.
 */
#define xmlXPathGetError(ctxt)	  ((ctxt)->error)

/**
 * xmlXPathCheckError:
 * @ctxt:  an XPath parser context
 *
 * Check if an XPath error was raised.
 *
 * Returns true if an error has been raised, false otherwise.
 */
#define xmlXPathCheckError(ctxt)  ((ctxt)->error != XPATH_EXPRESSION_OK)

/**
 * xmlXPathGetDocument:
 * @ctxt:  an XPath parser context
 *
 * Get the document of an XPath context.
 *
 * Returns the context document.
 */
#define xmlXPathGetDocument(ctxt)	((ctxt)->context->doc)

/**
 * xmlXPathGetContextNode:
 * @ctxt: an XPath parser context
 *
 * Get the context node of an XPath context.
 *
 * Returns the context node.
 */
#define xmlXPathGetContextNode(ctxt)	((ctxt)->context->node)

XMLPUBFUN int XMLCALL		
		xmlXPathPopBoolean	(xmlXPathParserContextPtr ctxt);
XMLPUBFUN double XMLCALL		
    		xmlXPathPopNumber	(xmlXPathParserContextPtr ctxt);
XMLPUBFUN xmlChar * XMLCALL	
    		xmlXPathPopString	(xmlXPathParserContextPtr ctxt);
XMLPUBFUN xmlNodeSetPtr XMLCALL	
    		xmlXPathPopNodeSet	(xmlXPathParserContextPtr ctxt);
XMLPUBFUN void * XMLCALL		
    		xmlXPathPopExternal	(xmlXPathParserContextPtr ctxt);

/**
 * xmlXPathReturnBoolean:
 * @ctxt:  an XPath parser context
 * @val:  a boolean
 *
 * Pushes the boolean @val on the context stack.
 */
#define xmlXPathReturnBoolean(ctxt, val)				\
    valuePush((ctxt), xmlXPathNewBoolean(val))

/**
 * xmlXPathReturnTrue:
 * @ctxt:  an XPath parser context
 *
 * Pushes true on the context stack.
 */
#define xmlXPathReturnTrue(ctxt)   xmlXPathReturnBoolean((ctxt), 1)

/**
 * xmlXPathReturnFalse:
 * @ctxt:  an XPath parser context
 *
 * Pushes false on the context stack.
 */
#define xmlXPathReturnFalse(ctxt)  xmlXPathReturnBoolean((ctxt), 0)

/**
 * xmlXPathReturnNumber:
 * @ctxt:  an XPath parser context
 * @val:  a double
 *
 * Pushes the double @val on the context stack.
 */
#define xmlXPathReturnNumber(ctxt, val)					\
    valuePush((ctxt), xmlXPathNewFloat(val))

/**
 * xmlXPathReturnString:
 * @ctxt:  an XPath parser context
 * @str:  a string
 *
 * Pushes the string @str on the context stack.
 */
#define xmlXPathReturnString(ctxt, str)					\
    valuePush((ctxt), xmlXPathWrapString(str))

/**
 * xmlXPathReturnEmptyString:
 * @ctxt:  an XPath parser context
 *
 * Pushes an empty string on the stack.
 */
#define xmlXPathReturnEmptyString(ctxt)					\
    valuePush((ctxt), xmlXPathNewCString(""))

/**
 * xmlXPathReturnNodeSet:
 * @ctxt:  an XPath parser context
 * @ns:  a node-set
 *
 * Pushes the node-set @ns on the context stack.
 */
#define xmlXPathReturnNodeSet(ctxt, ns)					\
    valuePush((ctxt), xmlXPathWrapNodeSet(ns))

/**
 * xmlXPathReturnEmptyNodeSet:
 * @ctxt:  an XPath parser context
 *
 * Pushes an empty node-set on the context stack.
 */
#define xmlXPathReturnEmptyNodeSet(ctxt)				\
    valuePush((ctxt), xmlXPathNewNodeSet(NULL))

/**
 * xmlXPathReturnExternal:
 * @ctxt:  an XPath parser context
 * @val:  user data
 *
 * Pushes user data on the context stack.
 */
#define xmlXPathReturnExternal(ctxt, val)				\
    valuePush((ctxt), xmlXPathWrapExternal(val))

/**
 * xmlXPathStackIsNodeSet:
 * @ctxt: an XPath parser context
 *
 * Check if the current value on the XPath stack is a node set or
 * an XSLT value tree.
 *
 * Returns true if the current object on the stack is a node-set.
 */
#define xmlXPathStackIsNodeSet(ctxt)					\
    (((ctxt)->value != NULL)						\
     && (((ctxt)->value->type == XPATH_NODESET)				\
         || ((ctxt)->value->type == XPATH_XSLT_TREE)))

/**
 * xmlXPathStackIsExternal:
 * @ctxt: an XPath parser context
 *
 * Checks if the current value on the XPath stack is an external
 * object.
 *
 * Returns true if the current object on the stack is an external
 * object.
 */
#define xmlXPathStackIsExternal(ctxt)					\
	((ctxt->value != NULL) && (ctxt->value->type == XPATH_USERS))

/**
 * xmlXPathEmptyNodeSet:
 * @ns:  a node-set
 *
 * Empties a node-set.
 */
#define xmlXPathEmptyNodeSet(ns)					\
    { while ((ns)->nodeNr > 0) (ns)->nodeTab[(ns)->nodeNr--] = NULL; }

/**
 * CHECK_ERROR:
 *
 * Macro to return from the function if an XPath error was detected.
 */
#define CHECK_ERROR							\
    if (ctxt->error != XPATH_EXPRESSION_OK) return

/**
 * CHECK_ERROR0:
 *
 * Macro to return 0 from the function if an XPath error was detected.
 */
#define CHECK_ERROR0							\
    if (ctxt->error != XPATH_EXPRESSION_OK) return(0)

/**
 * XP_ERROR:
 * @X:  the error code
 *
 * Macro to raise an XPath error and return.
 */
#define XP_ERROR(X)							\
    { xmlXPathErr(ctxt, X); return; }

/**
 * XP_ERROR0:
 * @X:  the error code
 *
 * Macro to raise an XPath error and return 0.
 */
#define XP_ERROR0(X)							\
    { xmlXPathErr(ctxt, X); return(0); }

/**
 * CHECK_TYPE:
 * @typeval:  the XPath type
 *
 * Macro to check that the value on top of the XPath stack is of a given
 * type.
 */
#define CHECK_TYPE(typeval)						\
    if ((ctxt->value == NULL) || (ctxt->value->type != typeval))	\
        XP_ERROR(XPATH_INVALID_TYPE)

/**
 * CHECK_TYPE0:
 * @typeval:  the XPath type
 *
 * Macro to check that the value on top of the XPath stack is of a given
 * type. Return(0) in case of failure
 */
#define CHECK_TYPE0(typeval)						\
    if ((ctxt->value == NULL) || (ctxt->value->type != typeval))	\
        XP_ERROR0(XPATH_INVALID_TYPE)

/**
 * CHECK_ARITY:
 * @x:  the number of expected args
 *
 * Macro to check that the number of args passed to an XPath function matches.
 */
#define CHECK_ARITY(x)							\
    if (ctxt == NULL) return;						\
    if (nargs != (x))							\
        XP_ERROR(XPATH_INVALID_ARITY);

/**
 * CAST_TO_STRING:
 *
 * Macro to try to cast the value on the top of the XPath stack to a string.
 */
#define CAST_TO_STRING							\
    if ((ctxt->value != NULL) && (ctxt->value->type != XPATH_STRING))	\
        xmlXPathStringFunction(ctxt, 1);

/**
 * CAST_TO_NUMBER:
 *
 * Macro to try to cast the value on the top of the XPath stack to a number.
 */
#define CAST_TO_NUMBER							\
    if ((ctxt->value != NULL) && (ctxt->value->type != XPATH_NUMBER))	\