source: vbox/trunk/src/libs/libxslt-1.1.22/libxslt/variables.c@ 26688

/*
 * variables.c: Implementation of the variable storage and lookup
 *
 * Reference:
 *   http://www.w3.org/TR/1999/REC-xslt-19991116
 *
 * See Copyright for the status of this software.
 *
 * daniel@veillard.com
 */

#define IN_LIBXSLT
#include "libxslt.h"

#include <string.h>

#include <libxml/xmlmemory.h>
#include <libxml/tree.h>
#include <libxml/valid.h>
#include <libxml/hash.h>
#include <libxml/xmlerror.h>
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>
#include <libxml/parserInternals.h>
#include <libxml/dict.h>
#include "xslt.h"
#include "xsltInternals.h"
#include "xsltutils.h"
#include "variables.h"
#include "transform.h"
#include "imports.h"
#include "preproc.h"
#include "keys.h"

#ifdef WITH_XSLT_DEBUG
 #define WITH_XSLT_DEBUG_VARIABLE
#endif

#ifdef XSLT_REFACTORED
const xmlChar *xsltDocFragFake = (const xmlChar *) " fake node libxslt";
#endif

const xmlChar *xsltComputingGlobalVarMarker =
 (const xmlChar *) " var/param being computed";

/************************************************************************
 *                                                                      *
 *  Result Value Tree (Result Tree Fragment) interfaces                 *
 *                                                                      *
 ************************************************************************/
/**
 * xsltCreateRVT:
 * @ctxt:  an XSLT transformation context
 *
 * Creates a Result Value Tree
 * (the XSLT 1.0 term for this is "Result Tree Fragment") 
 *
 * Returns the result value tree or NULL in case of API or internal errors.
 */
xmlDocPtr
xsltCreateRVT(xsltTransformContextPtr ctxt)
{
    xmlDocPtr container;

    /*
    * Question: Why is this function public?
    * Answer: It is called by the EXSLT module.
    */    
    if (ctxt == NULL)
        return(NULL);

    /*
    * Reuse a RTF from the cache if available.
    */
    if (ctxt->cache->RVT) {
        container = ctxt->cache->RVT;
        ctxt->cache->RVT = (xmlDocPtr) container->next;
        /* clear the internal pointers */
        container->next = NULL;
        container->prev = NULL;
        if (ctxt->cache->nbRVT > 0)
            ctxt->cache->nbRVT--;
#ifdef XSLT_DEBUG_PROFILE_CACHE
        ctxt->cache->dbgReusedRVTs++;
#endif
        return(container);
    }

    container = xmlNewDoc(NULL);
    if (container == NULL)
        return(NULL);
    container->dict = ctxt->dict;
    xmlDictReference(container->dict);
    XSLT_MARK_RES_TREE_FRAG(container);
    container->doc = container;
    container->parent = NULL;
    return(container);
}

/**
 * xsltRegisterTmpRVT:
 * @ctxt:  an XSLT transformation context
 * @RVT:  a result value tree (Result Tree Fragment)
 *
 * Registers the result value tree (XSLT 1.0 term: Result Tree Fragment)
 * in the garbage collector.
 * The fragment will be freed at the exit of the currently
 * instantiated xsl:template.
 * Obsolete; this function might produce massive memory overhead,
 * since the fragment is only freed when the current xsl:template
 * exits. Use xsltRegisterLocalRVT() instead.
 *
 * Returns 0 in case of success and -1 in case of API or internal errors.
 */
int
xsltRegisterTmpRVT(xsltTransformContextPtr ctxt, xmlDocPtr RVT)
{
    if ((ctxt == NULL) || (RVT == NULL))
        return(-1);

    /*
    * We'll restrict the lifetime of user-created fragments
    * insinde an xsl:variable and xsl:param to the lifetime of the
    * var/param itself.
    */
    if (ctxt->contextVariable != NULL) {
        RVT->next = (xmlNodePtr) XSLT_TCTXT_VARIABLE(ctxt)->fragment;
        XSLT_TCTXT_VARIABLE(ctxt)->fragment = RVT;
        return(0);
    }

    RVT->next = (xmlNodePtr) ctxt->tmpRVT;
    if (ctxt->tmpRVT != NULL)
        ctxt->tmpRVT->prev = (xmlNodePtr) RVT;
    ctxt->tmpRVT = RVT;
    return(0);
}

/**
 * xsltRegisterLocalRVT:
 * @ctxt:  an XSLT transformation context
 * @RVT:  a result value tree (Result Tree Fragment; xmlDocPtr)
 *
 * Registers a result value tree (XSLT 1.0 term: Result Tree Fragment)
 * in the RVT garbage collector.
 * The fragment will be freed when the instruction which created the
 * fragment exits.
 *
 * Returns 0 in case of success and -1 in case of API or internal errors.
 */
int
xsltRegisterLocalRVT(xsltTransformContextPtr ctxt,
                     xmlDocPtr RVT)
{
    if ((ctxt == NULL) || (RVT == NULL))
        return(-1);
    
    /*
    * When evaluating "select" expressions of xsl:variable
    * and xsl:param, we need to bind newly created tree fragments
    * to the variable itself; otherwise the tragment will be
    * freed before we leave the scope of a var.
    */
    if ((ctxt->contextVariable != NULL) &&
        (XSLT_TCTXT_VARIABLE(ctxt)->flags & XSLT_VAR_IN_SELECT))
    {
        RVT->next = (xmlNodePtr) XSLT_TCTXT_VARIABLE(ctxt)->fragment;
        XSLT_TCTXT_VARIABLE(ctxt)->fragment = RVT;
        return(0);
    }
    /*
    * Store the fragment in the scope of the current instruction.
    * If not reference by a returning instruction (like EXSLT's function),
    * then this fragment will be freed, when the instruction exits.
    */
    RVT->next = (xmlNodePtr) ctxt->localRVT;
    if (ctxt->localRVT != NULL)
        ctxt->localRVT->prev = (xmlNodePtr) RVT;
    ctxt->localRVT = RVT;
    /*
    * We need to keep track of the first registered fragment
    * for extension instructions which return fragments
    * (e.g. EXSLT'S function), in order to let
    * xsltExtensionInstructionResultFinalize() clear the
    * preserving flag on the fragments.
    */
    if (ctxt->localRVTBase == NULL)
        ctxt->localRVTBase = RVT;
    return(0);
}

/**
 * xsltExtensionInstructionResultFinalize:
 * @ctxt:  an XSLT transformation context
 *
 * Finalizes the data (e.g. result tree fragments) created
 * within a value-returning process (e.g. EXSLT's function).
 * Tree fragments marked as being returned by a function are
 * set to normal state, which means that the fragment garbage
 * collector will free them after the function-calling process exits.
 *
 * Returns 0 in case of success and -1 in case of API or internal errors.
 */
int
xsltExtensionInstructionResultFinalize(xsltTransformContextPtr ctxt)
{
    xmlDocPtr cur;

    if (ctxt == NULL)
        return(-1);
    if (ctxt->localRVTBase == NULL)
        return(0);
    /*
    * Enable remaining local tree fragments to be freed
    * by the fragment garbage collector.
    */
    cur = ctxt->localRVTBase;
    do {
        cur->psvi = NULL;
        cur = (xmlDocPtr) cur->next;
    } while (cur != NULL);
    return(0);
}

/**
 * xsltExtensionInstructionResultRegister:
 * @ctxt: an XSLT transformation context
 * @obj: an XPath object to be inspected for result tree fragments
 *
 * Marks the result of a value-returning extension instruction
 * in order to avoid it being garbage collected before the
 * extension instruction exits.
 * Note that one still has to additionally register any newly created
 * tree fragments (via xsltCreateRVT()) with xsltRegisterLocalRVT().
 *
 * Returns 0 in case of success and -1 in case of error.
 */
int
xsltExtensionInstructionResultRegister(xsltTransformContextPtr ctxt,
                                       xmlXPathObjectPtr obj)
{
    int i;
    xmlNodePtr cur;
    xmlDocPtr doc;

    if ((ctxt == NULL) || (obj == NULL))
        return(-1);

    /*
    * OPTIMIZE TODO: If no local variables/params and no local tree
    * fragments were created, then we don't need to analyse the XPath
    * objects for tree fragments.
    */

    if ((obj->type != XPATH_NODESET) && (obj->type != XPATH_XSLT_TREE))
        return(0);
    if ((obj->nodesetval == NULL) || (obj->nodesetval->nodeNr == 0))
        return(0);

    for (i = 0; i < obj->nodesetval->nodeNr; i++) {
        cur = obj->nodesetval->nodeTab[i];
        if (cur->type == XML_NAMESPACE_DECL) {
            /*
            * The XPath module sets the owner element of a ns-node on
            * the ns->next field.
            */
            if ((((xmlNsPtr) cur)->next != NULL) &&
                (((xmlNsPtr) cur)->next->type == XML_ELEMENT_NODE))
            {
                cur = (xmlNodePtr) ((xmlNsPtr) cur)->next;
                doc = cur->doc; 
            } else {
                xsltTransformError(ctxt, NULL, ctxt->inst,
                    "Internal error in "
                    "xsltExtensionInstructionResultRegister(): "
                    "Cannot retrieve the doc of a namespace node.\n");
                goto error;
            }
        } else {
            doc = cur->doc;
        }
        if (doc == NULL) {
            xsltTransformError(ctxt, NULL, ctxt->inst,
                "Internal error in "
                "xsltExtensionInstructionResultRegister(): "
                "Cannot retrieve the doc of a node.\n");
            goto error;
        }
        if (doc->name && (doc->name[0] == ' ')) {
            /*
            * This is a result tree fragment.
            * We'll use the @psvi field for reference counting.
            * TODO: How do we know if this is a value of a
            *  global variable or a doc acquired via the
            *  document() function?
            */
            doc->psvi = (void *) ((long) 1);
        }
    }

    return(0);
error:
    return(-1);
}

/**
 * xsltReleaseRVT:
 * @ctxt:  an XSLT transformation context
 * @RVT:  a result value tree (Result Tree Fragment)
 *
 * Either frees the RVT (which is an xmlDoc) or stores
 * it in the context's cache for later reuse.
 */
void
xsltReleaseRVT(xsltTransformContextPtr ctxt, xmlDocPtr RVT)
{
    if (RVT == NULL)
        return;

    if (ctxt && (ctxt->cache->nbRVT < 40)) {
        /*
        * Store the Result Tree Fragment.
        * Free the document info.
        */
        if (RVT->_private != NULL) {
            xsltFreeDocumentKeys((xsltDocumentPtr) RVT->_private);
            xmlFree(RVT->_private);
            RVT->_private = NULL;
        }
        /*
        * Clear the document tree.
        * REVISIT TODO: Do we expect ID/IDREF tables to be existent?    
        */
        if (RVT->children != NULL) {
            xmlFreeNodeList(RVT->children);
            RVT->children = NULL;
            RVT->last = NULL;
        }
        if (RVT->ids != NULL) {
            xmlFreeIDTable((xmlIDTablePtr) RVT->ids);
            RVT->ids = NULL;
        }
        if (RVT->refs != NULL) {
            xmlFreeRefTable((xmlRefTablePtr) RVT->refs);
            RVT->refs = NULL;
        }

        /*
        * Reset the reference counter.
        */
        RVT->psvi = 0;

        RVT->next = (xmlNodePtr) ctxt->cache->RVT;
        ctxt->cache->RVT = RVT;

        ctxt->cache->nbRVT++;

#ifdef XSLT_DEBUG_PROFILE_CACHE
        ctxt->cache->dbgCachedRVTs++;
#endif
        return;
    }
    /*
    * Free it.
    */
    if (RVT->_private != NULL) {
        xsltFreeDocumentKeys((xsltDocumentPtr) RVT->_private);
        xmlFree(RVT->_private);
    }
    xmlFreeDoc(RVT);
}

/**
 * xsltRegisterPersistRVT:
 * @ctxt:  an XSLT transformation context
 * @RVT:  a result value tree (Result Tree Fragment)
 *
 * Register the result value tree (XSLT 1.0 term: Result Tree Fragment)
 * in the fragment garbage collector.
 * The fragment will be freed when the transformation context is
 * freed.
 *
 * Returns 0 in case of success and -1 in case of error.
 */
int
xsltRegisterPersistRVT(xsltTransformContextPtr ctxt, xmlDocPtr RVT)
{
    if ((ctxt == NULL) || (RVT == NULL)) return(-1);

    RVT->next = (xmlNodePtr) ctxt->persistRVT;
    if (ctxt->persistRVT != NULL)
        ctxt->persistRVT->prev = (xmlNodePtr) RVT;
    ctxt->persistRVT = RVT;
    return(0);
}

/**
 * xsltFreeRVTs:
 * @ctxt:  an XSLT transformation context
 *
 * Frees all registered result value trees (Result Tree Fragments)
 * of the transformation. Internal function; should not be called
 * by user-code.
 */
void
xsltFreeRVTs(xsltTransformContextPtr ctxt)
{
    xmlDocPtr cur, next;

    if (ctxt == NULL)
        return;
    /*
    * Local fragments.
    */
    cur = ctxt->localRVT;
    while (cur != NULL) {
        next = (xmlDocPtr) cur->next;
        if (cur->_private != NULL) {
            xsltFreeDocumentKeys(cur->_private);
            xmlFree(cur->_private);
        }
        xmlFreeDoc(cur);
        cur = next;
    }
    ctxt->localRVT = NULL;
    /*
    * User-created per-template fragments.
    */
    cur = ctxt->tmpRVT;
    while (cur != NULL) {
        next = (xmlDocPtr) cur->next;
        if (cur->_private != NULL) {
            xsltFreeDocumentKeys(cur->_private);
            xmlFree(cur->_private);
        }
        xmlFreeDoc(cur);
        cur = next;
    }
    ctxt->tmpRVT = NULL;
    /*
    * Global fragments.
    */
    cur = ctxt->persistRVT;
    while (cur != NULL) {
        next = (xmlDocPtr) cur->next;
        if (cur->_private != NULL) {
            xsltFreeDocumentKeys(cur->_private);
            xmlFree(cur->_private);
        }
        xmlFreeDoc(cur);
        cur = next;
    }
    ctxt->persistRVT = NULL;
}

/************************************************************************
 *                                                                      *
 *                      Module interfaces                               *
 *                                                                      *
 ************************************************************************/

/**
 * xsltNewStackElem:
 *
 * Create a new XSLT ParserContext
 *
 * Returns the newly allocated xsltParserStackElem or NULL in case of error
 */
static xsltStackElemPtr
xsltNewStackElem(xsltTransformContextPtr ctxt)
{
    xsltStackElemPtr ret;
    /*
    * Reuse a stack item from the cache if available.
    */
    if (ctxt && ctxt->cache->stackItems) {
        ret = ctxt->cache->stackItems;
        ctxt->cache->stackItems = ret->next;
        ret->next = NULL;
        ctxt->cache->nbStackItems--;
#ifdef XSLT_DEBUG_PROFILE_CACHE
        ctxt->cache->dbgReusedVars++;
#endif
        return(ret);
    }
    ret = (xsltStackElemPtr) xmlMalloc(sizeof(xsltStackElem));
    if (ret == NULL) {
        xsltTransformError(NULL, NULL, NULL,
                "xsltNewStackElem : malloc failed\n");
        return(NULL);
    }
    memset(ret, 0, sizeof(xsltStackElem));
    ret->context = ctxt;
    return(ret);
}

/**
 * xsltCopyStackElem:
 * @elem:  an XSLT stack element
 *
 * Makes a copy of the stack element
 *
 * Returns the copy of NULL
 */
static xsltStackElemPtr
xsltCopyStackElem(xsltStackElemPtr elem) {
    xsltStackElemPtr cur;

    cur = (xsltStackElemPtr) xmlMalloc(sizeof(xsltStackElem));
    if (cur == NULL) {
        xsltTransformError(NULL, NULL, NULL,
                "xsltCopyStackElem : malloc failed\n");
        return(NULL);
    }
    memset(cur, 0, sizeof(xsltStackElem));
    cur->context = elem->context;
    cur->name = elem->name;
    cur->nameURI = elem->nameURI;
    cur->select = elem->select;
    cur->tree = elem->tree;
    cur->comp = elem->comp;    
    return(cur);
}

/**
 * xsltFreeStackElem:
 * @elem:  an XSLT stack element
 *
 * Free up the memory allocated by @elem
 */
static void
xsltFreeStackElem(xsltStackElemPtr elem) {
    if (elem == NULL)
        return;
    if (elem->value != NULL)
        xmlXPathFreeObject(elem->value);
    /*
    * Release the list of temporary Result Tree Fragments.
    */
    if (elem->fragment) {
        xmlDocPtr cur;

        while (elem->fragment != NULL) {
            cur = elem->fragment;
            elem->fragment = (xmlDocPtr) cur->next;

            if (elem->context &&
                (cur->psvi == (void *) ((long) 1)))
            {
                /*
                * This fragment is a result of an extension instruction
                * (e.g. XSLT's function) and needs to be preserved until
                * the instruction exits.
                * Example: The fragment of the variable must not be freed
                *  since it is returned by the EXSLT function:
                *  <f:function name="foo">
                *   <xsl:variable name="bar">
                *     <bar/>
                *   </xsl:variable>
                *   <f:result select="$bar"/>
                *  </f:function>
                * 
                */
                xsltRegisterLocalRVT(elem->context, cur);
            } else {
                xsltReleaseRVT((xsltTransformContextPtr) elem->context,
                    cur);
            }       
        }
    }
    /*
    * Cache or free the variable structure.
    */
    if (elem->context && (elem->context->cache->nbStackItems < 50)) {
        /*
        * Store the item in the cache.
        */
        xsltTransformContextPtr ctxt = elem->context;
        memset(elem, 0, sizeof(xsltStackElem));
        elem->context = ctxt;
        elem->next = ctxt->cache->stackItems;
        ctxt->cache->stackItems = elem; 
        ctxt->cache->nbStackItems++;
#ifdef XSLT_DEBUG_PROFILE_CACHE
        ctxt->cache->dbgCachedVars++;
#endif
        return;
    }
    xmlFree(elem);
}

/**
 * xsltFreeStackElemList:
 * @elem:  an XSLT stack element
 *
 * Free up the memory allocated by @elem
 */
void
xsltFreeStackElemList(xsltStackElemPtr elem) {
    xsltStackElemPtr next;
    
    while (elem != NULL) {
        next = elem->next;
        xsltFreeStackElem(elem);
        elem = next;
    }
}

/**
 * xsltStackLookup:
 * @ctxt:  an XSLT transformation context
 * @name:  the local part of the name
 * @nameURI:  the URI part of the name
 *
 * Locate an element in the stack based on its name.
 */
#if 0 /* TODO: Those seem to have been used for debugging. */
static int stack_addr = 0;
static int stack_cmp = 0;
#endif

static xsltStackElemPtr
xsltStackLookup(xsltTransformContextPtr ctxt, const xmlChar *name,
                const xmlChar *nameURI) {
    int i;
    xsltStackElemPtr cur;

    if ((ctxt == NULL) || (name == NULL) || (ctxt->varsNr == 0))
        return(NULL);

    /*
     * Do the lookup from the top of the stack, but
     * don't use params being computed in a call-param
     * First lookup expects the variable name and URI to
     * come from the disctionnary and hence pointer comparison.
     */
    for (i = ctxt->varsNr; i > ctxt->varsBase; i--) {
        cur = ctxt->varsTab[i-1];
        while (cur != NULL) {
            if ((cur->name == name) && (cur->nameURI == nameURI)) {
#if 0
                stack_addr++;
#endif
                return(cur);
            }
            cur = cur->next;
        }
    }

    /*
     * Redo the lookup with interned string compares
     * to avoid string compares.
     */
    name = xmlDictLookup(ctxt->dict, name, -1);
    if (nameURI != NULL)
        nameURI = xmlDictLookup(ctxt->dict, nameURI, -1);

    for (i = ctxt->varsNr; i > ctxt->varsBase; i--) {
        cur = ctxt->varsTab[i-1];
        while (cur != NULL) {
            if ((cur->name == name) && (cur->nameURI == nameURI)) {
#if 0
                stack_cmp++;
#endif
                return(cur);
            }
            cur = cur->next;
        }
    }

    return(NULL);
}

/**
 * xsltCheckStackElem:
 * @ctxt:  xn XSLT transformation context
 * @name:  the variable name
 * @nameURI:  the variable namespace URI
 *
 * Checks whether a variable or param is already defined.
 *
 * URGENT TODO: Checks for redefinition of vars/params should be
 *  done only at compilation time.
 *
 * Returns 1 if variable is present, 2 if param is present, 3 if this
 *         is an inherited param, 0 if not found, -1 in case of failure.
 */
static int
xsltCheckStackElem(xsltTransformContextPtr ctxt, const xmlChar *name,
                   const xmlChar *nameURI) {
    xsltStackElemPtr cur;

    if ((ctxt == NULL) || (name == NULL))
        return(-1);

    cur = xsltStackLookup(ctxt, name, nameURI);
    if (cur == NULL)
        return(0);
    if (cur->comp != NULL) {
        if (cur->comp->type == XSLT_FUNC_WITHPARAM)
            return(3);
        else if (cur->comp->type == XSLT_FUNC_PARAM)
            return(2);
    }
    
    return(1);
}

/**
 * xsltAddStackElem:
 * @ctxt:  xn XSLT transformation context
 * @elem:  a stack element
 *
 * Push an element (or list) onto the stack.
 * In case of a list, each member will be pushed into
 * a seperate slot; i.e. there's always 1 stack entry for
 * 1 stack element.
 *
 * Returns 0 in case of success, -1 in case of failure.
 */
static int
xsltAddStackElem(xsltTransformContextPtr ctxt, xsltStackElemPtr elem)
{
    if ((ctxt == NULL) || (elem == NULL))
        return(-1);

    do {
        if (ctxt->varsMax == 0) {
            ctxt->varsMax = 10;
            ctxt->varsTab =
                (xsltStackElemPtr *) xmlMalloc(ctxt->varsMax *
                sizeof(ctxt->varsTab[0]));
            if (ctxt->varsTab == NULL) {
                xmlGenericError(xmlGenericErrorContext, "malloc failed !\n");
                return (-1);
            }
        }
        if (ctxt->varsNr >= ctxt->varsMax) {
            ctxt->varsMax *= 2;
            ctxt->varsTab =
                (xsltStackElemPtr *) xmlRealloc(ctxt->varsTab,
                ctxt->varsMax *
                sizeof(ctxt->varsTab[0]));
            if (ctxt->varsTab == NULL) {
                xmlGenericError(xmlGenericErrorContext, "realloc failed !\n");
                return (-1);
            }
        }
        ctxt->varsTab[ctxt->varsNr++] = elem;
        ctxt->vars = elem;
        
        elem = elem->next;
    } while (elem != NULL);
    
    return(0);
}

/**
 * xsltAddStackElemList:
 * @ctxt:  xn XSLT transformation context
 * @elems:  a stack element list
 *
 * Push an element list onto the stack.
 *
 * Returns 0 in case of success, -1 in case of failure.
 */
int
xsltAddStackElemList(xsltTransformContextPtr ctxt, xsltStackElemPtr elems)
{
    return(xsltAddStackElem(ctxt, elems));
}

/************************************************************************
 *                                                                      *
 *                      Module interfaces                               *
 *                                                                      *
 ************************************************************************/

/**
 * xsltEvalVariable:
 * @ctxt:  the XSLT transformation context
 * @variable:  the variable or parameter item
 * @comp: the compiled XSLT instruction
 *
 * Evaluate a variable value.
 *
 * Returns the XPath Object value or NULL in case of error
 */
static xmlXPathObjectPtr
xsltEvalVariable(xsltTransformContextPtr ctxt, xsltStackElemPtr variable,
                 xsltStylePreCompPtr castedComp)
{
#ifdef XSLT_REFACTORED
    xsltStyleItemVariablePtr comp =
        (xsltStyleItemVariablePtr) castedComp;
#else
    xsltStylePreCompPtr comp = castedComp;
#endif   
    xmlXPathObjectPtr result = NULL;
    xmlNodePtr oldInst;

    if ((ctxt == NULL) || (variable == NULL))
        return(NULL);

    /*
    * A variable or parameter are evaluated on demand; thus the
    * context (of XSLT and XPath) need to be temporarily adjusted and
    * restored on exit.
    */
    oldInst = ctxt->inst;

#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
        "Evaluating variable '%s'\n", variable->name));
#endif
    if (variable->select != NULL) {
        xmlXPathCompExprPtr xpExpr = NULL;
        xmlDocPtr oldXPDoc;
        xmlNodePtr oldXPContextNode;
        int oldXPProximityPosition, oldXPContextSize, oldXPNsNr;
        xmlNsPtr *oldXPNamespaces;
        xmlXPathContextPtr xpctxt = ctxt->xpathCtxt;
        xsltStackElemPtr oldVar = ctxt->contextVariable;

        if ((comp != NULL) && (comp->comp != NULL)) {
            xpExpr = comp->comp;
        } else {
            xpExpr = xmlXPathCompile(variable->select);
        }
        if (xpExpr == NULL)
            return(NULL);
        /*
        * Save context states.
        */
        oldXPDoc = xpctxt->doc;
        oldXPContextNode = xpctxt->node;
        oldXPProximityPosition = xpctxt->proximityPosition;
        oldXPContextSize = xpctxt->contextSize;
        oldXPNamespaces = xpctxt->namespaces;
        oldXPNsNr = xpctxt->nsNr;
                
        xpctxt->node = ctxt->node;
        /*
        * OPTIMIZE TODO: Lame try to set the context doc.
        *   Get rid of this somehow in xpath.c.
        */
        if ((ctxt->node->type != XML_NAMESPACE_DECL) &&
            ctxt->node->doc)
            xpctxt->doc = ctxt->node->doc;
        /*
        * BUG TODO: The proximity position and the context size will
        *  potentially be wrong.
        *  Example: 
        *  <xsl:template select="foo">
        *    <xsl:variable name="pos" select="position()"/>
        *    <xsl:for-each select="bar">
        *      <xsl:value-of select="$pos"/>
        *    </xsl:for-each>
        *  </xsl:template>
        *  Here the proximity position and context size are changed
        *  to the context of <xsl:for-each select="bar">, but
        *  the variable needs to be evaluated in the context of
        *  <xsl:template select="foo">.
        */      
        if (comp != NULL) {
            
#ifdef XSLT_REFACTORED
            if (comp->inScopeNs != NULL) {
                xpctxt->namespaces = comp->inScopeNs->list;
                xpctxt->nsNr = comp->inScopeNs->xpathNumber;
            } else {
                xpctxt->namespaces = NULL;
                xpctxt->nsNr = 0;
            }
#else
            xpctxt->namespaces = comp->nsList;
            xpctxt->nsNr = comp->nsNr;
#endif
        } else {
            xpctxt->namespaces = NULL;
            xpctxt->nsNr = 0;
        }

        /*
        * We need to mark that we are "selecting" a var's value;
        * if any tree fragments are created inside the expression,
        * then those need to be stored inside the variable; otherwise
        * we'll eventually free still referenced fragments, before
        * we leave the scope of the variable.
        */
        ctxt->contextVariable = variable;       
        variable->flags |= XSLT_VAR_IN_SELECT;  
        
        result = xmlXPathCompiledEval(xpExpr, xpctxt);

        variable->flags ^= XSLT_VAR_IN_SELECT;
        /*
        * Restore Context states.
        */
        ctxt->contextVariable = oldVar;

        xpctxt->doc = oldXPDoc;
        xpctxt->node = oldXPContextNode;
        xpctxt->contextSize = oldXPContextSize;
        xpctxt->proximityPosition = oldXPProximityPosition;
        xpctxt->namespaces = oldXPNamespaces;
        xpctxt->nsNr = oldXPNsNr;

        if ((comp == NULL) || (comp->comp == NULL))
            xmlXPathFreeCompExpr(xpExpr);
        if (result == NULL) {
            xsltTransformError(ctxt, NULL,
                (comp != NULL) ? comp->inst : NULL,
                "Failed to evaluate the expression of variable '%s'.\n",
                variable->name);
            ctxt->state = XSLT_STATE_STOPPED;

#ifdef WITH_XSLT_DEBUG_VARIABLE
#ifdef LIBXML_DEBUG_ENABLED
        } else {
            if ((xsltGenericDebugContext == stdout) ||
                (xsltGenericDebugContext == stderr))
                xmlXPathDebugDumpObject((FILE *)xsltGenericDebugContext,
                                        result, 0);
#endif
#endif
        }
    } else {
        if (variable->tree == NULL) {
            result = xmlXPathNewCString("");
        } else {            
            if (variable->tree) {
                xmlDocPtr container;
                xmlNodePtr oldInsert;
                xmlDocPtr  oldOutput;
                xsltStackElemPtr oldVar = ctxt->contextVariable;

                /*
                * Generate a result tree fragment.
                */
                container = xsltCreateRVT(ctxt);
                if (container == NULL)
                    goto error;
                /*
                * NOTE: Local Result Tree Fragments of params/variables
                * are not registered globally anymore; the life-time
                * is not directly dependant of the param/variable itself.
                *
                * OLD: xsltRegisterTmpRVT(ctxt, container);
                */
                /*
                * Attach the Result Tree Fragment to the variable;
                * when the variable is freed, it will also free 
                * the Result Tree Fragment.
                */
                variable->fragment = container;
                
                oldOutput = ctxt->output;
                oldInsert = ctxt->insert;               
                
                ctxt->output = container;
                ctxt->insert = (xmlNodePtr) container;
                ctxt->contextVariable = variable;
                /*
                * Process the sequence constructor (variable->tree).
                * The resulting tree will be held by @container.
                */
                xsltApplyOneTemplate(ctxt, ctxt->node, variable->tree,
                    NULL, NULL);

                ctxt->contextVariable = oldVar;         
                ctxt->insert = oldInsert;
                ctxt->output = oldOutput;
                
                result = xmlXPathNewValueTree((xmlNodePtr) container);
            }
            if (result == NULL) {
                result = xmlXPathNewCString("");
            } else {
                /*
                * Freeing is not handled there anymore.
                * QUESTION TODO: What does the above comment mean?
                */
                result->boolval = 0; 
            }
#ifdef WITH_XSLT_DEBUG_VARIABLE
#ifdef LIBXML_DEBUG_ENABLED

            if ((xsltGenericDebugContext == stdout) ||
                (xsltGenericDebugContext == stderr))
                xmlXPathDebugDumpObject((FILE *)xsltGenericDebugContext,
                                        result, 0);
#endif
#endif
        }
    }

error:
    ctxt->inst = oldInst;
    return(result);
}

/**
 * xsltEvalGlobalVariable:
 * @elem:  the variable or parameter
 * @ctxt:  the XSLT transformation context
 *
 * Evaluates a the value of a global xsl:variable or
 * xsl:param declaration.
 *
 * Returns the XPath Object value or NULL in case of error
 */
static xmlXPathObjectPtr
xsltEvalGlobalVariable(xsltStackElemPtr elem, xsltTransformContextPtr ctxt)
{
    xmlXPathObjectPtr result = NULL;
    xmlNodePtr oldInst;
    const xmlChar* oldVarName;

#ifdef XSLT_REFACTORED
    xsltStyleBasicItemVariablePtr comp;
#else
    xsltStylePreCompPtr comp;
#endif

    if ((ctxt == NULL) || (elem == NULL))
        return(NULL);
    if (elem->computed)
        return(elem->value);


#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
        "Evaluating global variable %s\n", elem->name));
#endif

#ifdef WITH_DEBUGGER
    if ((ctxt->debugStatus != XSLT_DEBUG_NONE) &&
        elem->comp && elem->comp->inst)
        xslHandleDebugger(elem->comp->inst, NULL, NULL, ctxt);
#endif

    oldInst = ctxt->inst;
    comp = elem->comp;
    oldVarName = elem->name;
    elem->name = xsltComputingGlobalVarMarker;
    /*
    * OPTIMIZE TODO: We should consider instantiating global vars/params
    *  on-demand. The vars/params don't need to be evaluated if never
    *  called; and in the case of global params, if values for such params
    *  are provided by the user.
    */
    if (elem->select != NULL) {         
        xmlXPathCompExprPtr xpExpr = NULL;
        xmlDocPtr oldXPDoc;
        xmlNodePtr oldXPContextNode;
        int oldXPProximityPosition, oldXPContextSize, oldXPNsNr;
        xmlNsPtr *oldXPNamespaces;
        xmlXPathContextPtr xpctxt = ctxt->xpathCtxt;

        if ((comp != NULL) && (comp->comp != NULL)) {
            xpExpr = comp->comp;
        } else {
            xpExpr = xmlXPathCompile(elem->select);
        }
        if (xpExpr == NULL)
            goto error;
        
        
        if (comp != NULL)
            ctxt->inst = comp->inst;
        else
            ctxt->inst = NULL;
        /*
        * SPEC XSLT 1.0:
        * "At top-level, the expression or template specifying the
        *  variable value is evaluated with the same context as that used
        *  to process the root node of the source document: the current
        *  node is the root node of the source document and the current
        *  node list is a list containing just the root node of the source
        *  document."   
        */
        /*
        * Save context states.
        */
        oldXPDoc = xpctxt->doc;
        oldXPContextNode = xpctxt->node;
        oldXPProximityPosition = xpctxt->proximityPosition;
        oldXPContextSize = xpctxt->contextSize;
        oldXPNamespaces = xpctxt->namespaces;
        oldXPNsNr = xpctxt->nsNr;
                
        xpctxt->node = ctxt->initialContextNode;
        xpctxt->doc = ctxt->initialContextDoc;
        xpctxt->contextSize = 1;
        xpctxt->proximityPosition = 1;
                
        if (comp != NULL) {
            
#ifdef XSLT_REFACTORED
            if (comp->inScopeNs != NULL) {
                xpctxt->namespaces = comp->inScopeNs->list;
                xpctxt->nsNr = comp->inScopeNs->xpathNumber;
            } else {
                xpctxt->namespaces = NULL;
                xpctxt->nsNr = 0;
            }
#else
            xpctxt->namespaces = comp->nsList;
            xpctxt->nsNr = comp->nsNr;
#endif
        } else {
            xpctxt->namespaces = NULL;
            xpctxt->nsNr = 0;
        }
        
        result = xmlXPathCompiledEval(xpExpr, xpctxt);

        /*
        * Restore Context states.
        */
        xpctxt->doc = oldXPDoc;
        xpctxt->node = oldXPContextNode;
        xpctxt->contextSize = oldXPContextSize;
        xpctxt->proximityPosition = oldXPProximityPosition;
        xpctxt->namespaces = oldXPNamespaces;
        xpctxt->nsNr = oldXPNsNr;

        if ((comp == NULL) || (comp->comp == NULL))
            xmlXPathFreeCompExpr(xpExpr);
        if (result == NULL) {
            if (comp == NULL)
                xsltTransformError(ctxt, NULL, NULL,
                    "Evaluating global variable %s failed\n", elem->name);
            else
                xsltTransformError(ctxt, NULL, comp->inst,
                    "Evaluating global variable %s failed\n", elem->name);
            ctxt->state = XSLT_STATE_STOPPED;
#ifdef WITH_XSLT_DEBUG_VARIABLE
#ifdef LIBXML_DEBUG_ENABLED
        } else {
            if ((xsltGenericDebugContext == stdout) ||
                (xsltGenericDebugContext == stderr))
                xmlXPathDebugDumpObject((FILE *)xsltGenericDebugContext,
                                        result, 0);
#endif
#endif
        }
    } else {
        if (elem->tree == NULL) {
            result = xmlXPathNewCString("");
        } else {
            xmlDocPtr container;
            xmlNodePtr oldInsert;
            xmlDocPtr  oldOutput, oldXPDoc;         
            /*
            * Generate a result tree fragment.
            */
            container = xsltCreateRVT(ctxt);
            if (container == NULL)
                goto error;
            /*
            * Let the lifetime of the tree fragment be handled by
            * the Libxslt's garbage collector.
            */
            xsltRegisterPersistRVT(ctxt, container);        

            oldOutput = ctxt->output;
            oldInsert = ctxt->insert;

            oldXPDoc = ctxt->xpathCtxt->doc;
            
            ctxt->output = container;       
            ctxt->insert = (xmlNodePtr) container;

            ctxt->xpathCtxt->doc = ctxt->initialContextDoc;
            /*
            * Process the sequence constructor.
            */
            xsltApplyOneTemplate(ctxt, ctxt->node, elem->tree, NULL, NULL);

            ctxt->xpathCtxt->doc = oldXPDoc;

            ctxt->insert = oldInsert;
            ctxt->output = oldOutput;
            
            result = xmlXPathNewValueTree((xmlNodePtr) container);
            if (result == NULL) {
                result = xmlXPathNewCString("");
            } else {
                result->boolval = 0; /* Freeing is not handled there anymore */
            }
#ifdef WITH_XSLT_DEBUG_VARIABLE
#ifdef LIBXML_DEBUG_ENABLED
            if ((xsltGenericDebugContext == stdout) ||
                (xsltGenericDebugContext == stderr))
                xmlXPathDebugDumpObject((FILE *)xsltGenericDebugContext,
                                        result, 0);
#endif
#endif
        }
    }

error:
    elem->name = oldVarName;
    ctxt->inst = oldInst;
    if (result != NULL) {
        elem->value = result;
        elem->computed = 1;
    }
    return(result);
}

/**
 * xsltEvalGlobalVariables:
 * @ctxt:  the XSLT transformation context
 *
 * Evaluates all global variables and parameters of a stylesheet.
 * For internal use only. This is called at start of a transformation.
 *
 * Returns 0 in case of success, -1 in case of error
 */
int
xsltEvalGlobalVariables(xsltTransformContextPtr ctxt) {
    xsltStackElemPtr elem;
    xsltStylesheetPtr style;    

    if ((ctxt == NULL) || (ctxt->document == NULL))
        return(-1);
 
#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
        "Registering global variables\n"));
#endif
    /*
     * Walk the list from the stylesheets and populate the hash table
     */
    style = ctxt->style;
    while (style != NULL) {
        elem = style->variables;
        
#ifdef WITH_XSLT_DEBUG_VARIABLE
        if ((style->doc != NULL) && (style->doc->URL != NULL)) {
            XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                             "Registering global variables from %s\n",
                             style->doc->URL));
        }
#endif

        while (elem != NULL) {
            xsltStackElemPtr def;

            /*
             * Global variables are stored in the variables pool.
             */
            def = (xsltStackElemPtr) 
                    xmlHashLookup2(ctxt->globalVars,
                                 elem->name, elem->nameURI);
            if (def == NULL) {

                def = xsltCopyStackElem(elem);
                xmlHashAddEntry2(ctxt->globalVars,
                                 elem->name, elem->nameURI, def);
            } else if ((elem->comp != NULL) &&
                       (elem->comp->type == XSLT_FUNC_VARIABLE)) {
                /*
                 * Redefinition of variables from a different stylesheet
                 * should not generate a message.
                 */
                if ((elem->comp->inst != NULL) &&
                    (def->comp != NULL) && (def->comp->inst != NULL) &&
                    (elem->comp->inst->doc == def->comp->inst->doc))
                {
                    xsltTransformError(ctxt, style, elem->comp->inst,
                        "Global variable %s already defined\n", elem->name);
                    if (style != NULL) style->errors++;
                }
            }
            elem = elem->next;
        }

        style = xsltNextImport(style);
    }

    /*
     * This part does the actual evaluation
     */    
    xmlHashScan(ctxt->globalVars,
                (xmlHashScanner) xsltEvalGlobalVariable, ctxt);

    return(0);
}

/**
 * xsltRegisterGlobalVariable:
 * @style:  the XSLT transformation context
 * @name:  the variable name
 * @ns_uri:  the variable namespace URI
 * @sel:  the expression which need to be evaluated to generate a value
 * @tree:  the subtree if sel is NULL
 * @comp:  the precompiled value
 * @value:  the string value if available
 *
 * Register a new variable value. If @value is NULL it unregisters
 * the variable
 *
 * Returns 0 in case of success, -1 in case of error
 */
static int
xsltRegisterGlobalVariable(xsltStylesheetPtr style, const xmlChar *name,
                     const xmlChar *ns_uri, const xmlChar *sel,
                     xmlNodePtr tree, xsltStylePreCompPtr comp,
                     const xmlChar *value) {
    xsltStackElemPtr elem, tmp;
    if (style == NULL)
        return(-1);
    if (name == NULL)
        return(-1);
    if (comp == NULL)
        return(-1);

#ifdef WITH_XSLT_DEBUG_VARIABLE
    if (comp->type == XSLT_FUNC_PARAM)
        xsltGenericDebug(xsltGenericDebugContext,
                         "Defining global param %s\n", name);
    else
        xsltGenericDebug(xsltGenericDebugContext,
                         "Defining global variable %s\n", name);
#endif

    elem = xsltNewStackElem(NULL);
    if (elem == NULL)
        return(-1);
    elem->comp = comp;
    elem->name = xmlDictLookup(style->dict, name, -1);
    elem->select = xmlDictLookup(style->dict, sel, -1);
    if (ns_uri)
        elem->nameURI = xmlDictLookup(style->dict, ns_uri, -1);
    elem->tree = tree;
    tmp = style->variables;
    if (tmp == NULL) {
        elem->next = NULL;
        style->variables = elem;
    } else {
        while (tmp != NULL) {
            if ((elem->comp->type == XSLT_FUNC_VARIABLE) &&
                (tmp->comp->type == XSLT_FUNC_VARIABLE) &&
                (xmlStrEqual(elem->name, tmp->name)) &&
                ((elem->nameURI == tmp->nameURI) ||
                 (xmlStrEqual(elem->nameURI, tmp->nameURI))))
            {
                xsltTransformError(NULL, style, comp->inst,
                "redefinition of global variable %s\n", elem->name);
                style->errors++;
            }
            if (tmp->next == NULL)
                break;
            tmp = tmp->next;
        }
        elem->next = NULL;
        tmp->next = elem;
    }
    if (value != NULL) {
        elem->computed = 1;
        elem->value = xmlXPathNewString(value);
    }
    return(0);
}

/**
 * xsltProcessUserParamInternal
 *
 * @ctxt:  the XSLT transformation context
 * @name:  a null terminated parameter name
 * @value: a null terminated value (may be an XPath expression)
 * @eval:  0 to treat the value literally, else evaluate as XPath expression
 *
 * If @eval is 0 then @value is treated literally and is stored in the global
 * parameter/variable table without any change.
 *
 * Uf @eval is 1 then @value is treated as an XPath expression and is
 * evaluated.  In this case, if you want to pass a string which will be
 * interpreted literally then it must be enclosed in single or double quotes.
 * If the string contains single quotes (double quotes) then it cannot be
 * enclosed single quotes (double quotes).  If the string which you want to
 * be treated literally contains both single and double quotes (e.g. Meet
 * at Joe's for "Twelfth Night" at 7 o'clock) then there is no suitable
 * quoting character.  You cannot use &apos; or &quot; inside the string
 * because the replacement of character entities with their equivalents is
 * done at a different stage of processing.  The solution is to call
 * xsltQuoteUserParams or xsltQuoteOneUserParam.
 *
 * This needs to be done on parsed stylesheets before starting to apply
 * transformations.  Normally this will be called (directly or indirectly)
 * only from xsltEvalUserParams, xsltEvalOneUserParam, xsltQuoteUserParams,
 * or xsltQuoteOneUserParam.
 *
 * Returns 0 in case of success, -1 in case of error
 */

static
int
xsltProcessUserParamInternal(xsltTransformContextPtr ctxt,
                             const xmlChar * name,
                             const xmlChar * value,
                             int eval) {

    xsltStylesheetPtr style;
    const xmlChar *prefix;
    const xmlChar *href;
    xmlXPathCompExprPtr xpExpr;
    xmlXPathObjectPtr result;
    
    xsltStackElemPtr elem;
    int res;
    void *res_ptr;

    if (ctxt == NULL)
        return(-1);
    if (name == NULL)
        return(0);
    if (value == NULL)
        return(0);

    style = ctxt->style;

#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
            "Evaluating user parameter %s=%s\n", name, value));
#endif

    /*
     * Name lookup
     */

    name = xsltSplitQName(ctxt->dict, name, &prefix);
    href = NULL;
    if (prefix != NULL) {
        xmlNsPtr ns;

        ns = xmlSearchNs(style->doc, xmlDocGetRootElement(style->doc),
                         prefix);
        if (ns == NULL) {
            xsltTransformError(ctxt, style, NULL,
            "user param : no namespace bound to prefix %s\n", prefix);
            href = NULL;
        } else {
            href = ns->href;
        }
    }

    if (name == NULL)
        return (-1);

    res_ptr = xmlHashLookup2(ctxt->globalVars, name, href);
    if (res_ptr != 0) {
        xsltTransformError(ctxt, style, NULL,
            "Global parameter %s already defined\n", name);
    }
    if (ctxt->globalVars == NULL)
        ctxt->globalVars = xmlHashCreate(20);

    /*
     * do not overwrite variables with parameters from the command line
     */
    while (style != NULL) {
        elem = ctxt->style->variables;
        while (elem != NULL) {
            if ((elem->comp != NULL) &&
                (elem->comp->type == XSLT_FUNC_VARIABLE) &&
                (xmlStrEqual(elem->name, name)) &&
                (xmlStrEqual(elem->nameURI, href))) {
                return(0);
            }
            elem = elem->next;
        }
        style = xsltNextImport(style);
    }
    style = ctxt->style;
    elem = NULL;

    /*
     * Do the evaluation if @eval is non-zero.
     */

    result = NULL;
    if (eval != 0) {
        xpExpr = xmlXPathCompile(value);
        if (xpExpr != NULL) {
            xmlDocPtr oldXPDoc;
            xmlNodePtr oldXPContextNode;
            int oldXPProximityPosition, oldXPContextSize, oldXPNsNr;
            xmlNsPtr *oldXPNamespaces;
            xmlXPathContextPtr xpctxt = ctxt->xpathCtxt;
           
            /*
            * Save context states.
            */
            oldXPDoc = xpctxt->doc;
            oldXPContextNode = xpctxt->node;
            oldXPProximityPosition = xpctxt->proximityPosition;
            oldXPContextSize = xpctxt->contextSize;
            oldXPNamespaces = xpctxt->namespaces;
            oldXPNsNr = xpctxt->nsNr;

            /*
            * SPEC XSLT 1.0:
            * "At top-level, the expression or template specifying the
            *  variable value is evaluated with the same context as that used
            *  to process the root node of the source document: the current
            *  node is the root node of the source document and the current
            *  node list is a list containing just the root node of the source
            *  document."
            */
            xpctxt->doc = ctxt->initialContextDoc;          
            xpctxt->node = ctxt->initialContextNode;        
            xpctxt->contextSize = 1;
            xpctxt->proximityPosition = 1;
            /* 
            * There is really no in scope namespace for parameters on the
            * command line.
            */
            xpctxt->namespaces = NULL;
            xpctxt->nsNr = 0;      
            
            result = xmlXPathCompiledEval(xpExpr, xpctxt);
            
            /*
            * Restore Context states.
            */
            xpctxt->doc = oldXPDoc;
            xpctxt->node = oldXPContextNode;
            xpctxt->contextSize = oldXPContextSize;
            xpctxt->proximityPosition = oldXPProximityPosition;
            xpctxt->namespaces = oldXPNamespaces;
            xpctxt->nsNr = oldXPNsNr;
            
            xmlXPathFreeCompExpr(xpExpr);
        }
        if (result == NULL) {
            xsltTransformError(ctxt, style, NULL,
                "Evaluating user parameter %s failed\n", name);
            ctxt->state = XSLT_STATE_STOPPED;
            return(-1);
        }
    }

    /* 
     * If @eval is 0 then @value is to be taken literally and result is NULL
     * 
     * If @eval is not 0, then @value is an XPath expression and has been
     * successfully evaluated and result contains the resulting value and
     * is not NULL.
     *
     * Now create an xsltStackElemPtr for insertion into the context's
     * global variable/parameter hash table.
     */

#ifdef WITH_XSLT_DEBUG_VARIABLE
#ifdef LIBXML_DEBUG_ENABLED
    if ((xsltGenericDebugContext == stdout) ||
        (xsltGenericDebugContext == stderr))
            xmlXPathDebugDumpObject((FILE *)xsltGenericDebugContext,
                                    result, 0);
#endif
#endif

    elem = xsltNewStackElem(NULL);
    if (elem != NULL) {
        elem->name = name;
        elem->select = xmlDictLookup(ctxt->dict, value, -1);
        if (href != NULL)
            elem->nameURI = xmlDictLookup(ctxt->dict, href, -1);
        elem->tree = NULL;
        elem->computed = 1;
        if (eval == 0) {
            elem->value = xmlXPathNewString(value);
        } 
        else {
            elem->value = result;
        }
    }

    /*
     * Global parameters are stored in the XPath context variables pool.
     */

    res = xmlHashAddEntry2(ctxt->globalVars, name, href, elem);
    if (res != 0) {
        xsltFreeStackElem(elem);
        xsltTransformError(ctxt, style, NULL,
            "Global parameter %s already defined\n", name);
    }
    return(0);
}

/**
 * xsltEvalUserParams:
 *
 * @ctxt:  the XSLT transformation context
 * @params:  a NULL terminated array of parameters name/value tuples
 *
 * Evaluate the global variables of a stylesheet. This needs to be
 * done on parsed stylesheets before starting to apply transformations.
 * Each of the parameters is evaluated as an XPath expression and stored
 * in the global variables/parameter hash table.  If you want your
 * parameter used literally, use xsltQuoteUserParams.
 *
 * Returns 0 in case of success, -1 in case of error
 */
 
int
xsltEvalUserParams(xsltTransformContextPtr ctxt, const char **params) {
    int indx = 0;
    const xmlChar *name;
    const xmlChar *value;

    if (params == NULL)
        return(0);
    while (params[indx] != NULL) {
        name = (const xmlChar *) params[indx++];
        value = (const xmlChar *) params[indx++];
        if (xsltEvalOneUserParam(ctxt, name, value) != 0) 
            return(-1);
    }
    return 0;
}

/**
 * xsltQuoteUserParams:
 *
 * @ctxt:  the XSLT transformation context
 * @params:  a NULL terminated arry of parameters names/values tuples
 *
 * Similar to xsltEvalUserParams, but the values are treated literally and
 * are * *not* evaluated as XPath expressions. This should be done on parsed
 * stylesheets before starting to apply transformations.
 *
 * Returns 0 in case of success, -1 in case of error.
 */
 
int
xsltQuoteUserParams(xsltTransformContextPtr ctxt, const char **params) {
    int indx = 0;
    const xmlChar *name;
    const xmlChar *value;

    if (params == NULL)
        return(0);
    while (params[indx] != NULL) {
        name = (const xmlChar *) params[indx++];
        value = (const xmlChar *) params[indx++];
        if (xsltQuoteOneUserParam(ctxt, name, value) != 0) 
            return(-1);
    }
    return 0;
}

/**
 * xsltEvalOneUserParam:
 * @ctxt:  the XSLT transformation context
 * @name:  a null terminated string giving the name of the parameter
 * @value:  a null terminated string giving the XPath expression to be evaluated
 *
 * This is normally called from xsltEvalUserParams to process a single
 * parameter from a list of parameters.  The @value is evaluated as an
 * XPath expression and the result is stored in the context's global
 * variable/parameter hash table.
 *
 * To have a parameter treated literally (not as an XPath expression)
 * use xsltQuoteUserParams (or xsltQuoteOneUserParam).  For more
 * details see description of xsltProcessOneUserParamInternal.
 *
 * Returns 0 in case of success, -1 in case of error.
 */

int
xsltEvalOneUserParam(xsltTransformContextPtr ctxt,
                     const xmlChar * name,
                     const xmlChar * value) {
    return xsltProcessUserParamInternal(ctxt, name, value,
                                        1 /* xpath eval ? */);
}

/**
 * xsltQuoteOneUserParam:
 * @ctxt:  the XSLT transformation context
 * @name:  a null terminated string giving the name of the parameter
 * @value:  a null terminated string giving the parameter value
 *
 * This is normally called from xsltQuoteUserParams to process a single
 * parameter from a list of parameters.  The @value is stored in the
 * context's global variable/parameter hash table.
 *
 * Returns 0 in case of success, -1 in case of error.
 */

int
xsltQuoteOneUserParam(xsltTransformContextPtr ctxt,
                         const xmlChar * name,
                         const xmlChar * value) {
    return xsltProcessUserParamInternal(ctxt, name, value,
                                        0 /* xpath eval ? */);
}

/**
 * xsltBuildVariable:
 * @ctxt:  the XSLT transformation context
 * @comp:  the precompiled form
 * @tree:  the tree if select is NULL
 *
 * Computes a new variable value.
 *
 * Returns the xsltStackElemPtr or NULL in case of error
 */
static xsltStackElemPtr
xsltBuildVariable(xsltTransformContextPtr ctxt,
                  xsltStylePreCompPtr castedComp,
                  xmlNodePtr tree)
{
#ifdef XSLT_REFACTORED
    xsltStyleBasicItemVariablePtr comp =
        (xsltStyleBasicItemVariablePtr) castedComp;
#else
    xsltStylePreCompPtr comp = castedComp;
#endif 
    xsltStackElemPtr elem;

#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                     "Building variable %s", comp->name));
    if (comp->select != NULL)
        XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                         " select %s", comp->select));
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext, "\n"));
#endif

    elem = xsltNewStackElem(ctxt);
    if (elem == NULL)
        return(NULL);
    elem->comp = (xsltStylePreCompPtr) comp;
    elem->name = comp->name;
    elem->select = comp->select;
    elem->nameURI = comp->ns;
    elem->tree = tree;
    elem->value = xsltEvalVariable(ctxt, elem,
        (xsltStylePreCompPtr) comp);
    if (elem->value != NULL)
        elem->computed = 1;
    return(elem);
}

/**
 * xsltRegisterVariable:
 * @ctxt:  the XSLT transformation context
 * @comp: the compiled XSLT-variable (or param) instruction
 * @tree:  the tree if select is NULL
 * @isParam:  indicates if this is a parameter
 *
 * Computes and registers a new variable.
 *
 * Returns 0 in case of success, -1 in case of error
 */
static int
xsltRegisterVariable(xsltTransformContextPtr ctxt,
                     xsltStylePreCompPtr castedComp,
                     xmlNodePtr tree, int isParam)
{
#ifdef XSLT_REFACTORED
    xsltStyleBasicItemVariablePtr comp =
        (xsltStyleBasicItemVariablePtr) castedComp;
#else
    xsltStylePreCompPtr comp = castedComp;
    int present;
#endif
    xsltStackElemPtr variable;    
    
#ifdef XSLT_REFACTORED
    /*
    * REFACTORED NOTE: Redefinitions of vars/params are checked
    *  at compilation time in the refactored code.
    * xsl:with-param parameters are checked in xsltApplyXSLTTemplate().
    */
#else
    present = xsltCheckStackElem(ctxt, comp->name, comp->ns);
    if (isParam == 0) { 
        if ((present != 0) && (present != 3)) {
            /* TODO: report QName. */
            xsltTransformError(ctxt, NULL, comp->inst,
                "XSLT-variable: Redefinition of variable '%s'.\n", comp->name);
            return(0);
        }
    } else if (present != 0) {
        if ((present == 1) || (present == 2)) {
            /* TODO: report QName. */
            xsltTransformError(ctxt, NULL, comp->inst,
                "XSLT-param: Redefinition of parameter '%s'.\n", comp->name);
            return(0);
        }
#ifdef WITH_XSLT_DEBUG_VARIABLE
        XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                 "param %s defined by caller\n", comp->name));
#endif
        return(0);
    }
#endif /* else of XSLT_REFACTORED */

    variable = xsltBuildVariable(ctxt, (xsltStylePreCompPtr) comp, tree);
    xsltAddStackElem(ctxt, variable);
    return(0);
}

/**
 * xsltGlobalVariableLookup:
 * @ctxt:  the XSLT transformation context
 * @name:  the variable name
 * @ns_uri:  the variable namespace URI
 *
 * Search in the Variable array of the context for the given
 * variable value.
 *
 * Returns the value or NULL if not found
 */
static xmlXPathObjectPtr
xsltGlobalVariableLookup(xsltTransformContextPtr ctxt, const xmlChar *name,
                         const xmlChar *ns_uri) {
    xsltStackElemPtr elem;
    xmlXPathObjectPtr ret = NULL;

    /*
     * Lookup the global variables in XPath global variable hash table
     */
    if ((ctxt->xpathCtxt == NULL) || (ctxt->globalVars == NULL))
        return(NULL);
    elem = (xsltStackElemPtr)
            xmlHashLookup2(ctxt->globalVars, name, ns_uri);
    if (elem == NULL) {
#ifdef WITH_XSLT_DEBUG_VARIABLE
        XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                         "global variable not found %s\n", name));
#endif
        return(NULL);
    }
    /*
    * URGENT TODO: Move the detection of recursive definitions
    * to compile-time.
    */
    if (elem->computed == 0) {
        if (elem->name == xsltComputingGlobalVarMarker) {
            xsltTransformError(ctxt, NULL, elem->comp->inst,
                "Recursive definition of %s\n", name);
            return(NULL);
        }
        ret = xsltEvalGlobalVariable(elem, ctxt);
    } else
        ret = elem->value;
    return(xmlXPathObjectCopy(ret));
}

/**
 * xsltVariableLookup:
 * @ctxt:  the XSLT transformation context
 * @name:  the variable name
 * @ns_uri:  the variable namespace URI
 *
 * Search in the Variable array of the context for the given
 * variable value.
 *
 * Returns the value or NULL if not found
 */
xmlXPathObjectPtr
xsltVariableLookup(xsltTransformContextPtr ctxt, const xmlChar *name,
                   const xmlChar *ns_uri) {
    xsltStackElemPtr elem;

    if (ctxt == NULL)
        return(NULL);

    elem = xsltStackLookup(ctxt, name, ns_uri);
    if (elem == NULL) {
        return(xsltGlobalVariableLookup(ctxt, name, ns_uri));
    }
    if (elem->computed == 0) {
#ifdef WITH_XSLT_DEBUG_VARIABLE
        XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                         "uncomputed variable %s\n", name));
#endif
        elem->value = xsltEvalVariable(ctxt, elem, NULL);
        elem->computed = 1;
    }
    if (elem->value != NULL)
        return(xmlXPathObjectCopy(elem->value));
#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                     "variable not found %s\n", name));
#endif
    return(NULL);
}

/**
 * xsltParseStylesheetCallerParam:
 * @ctxt:  the XSLT transformation context 
 * @inst:  the xsl:with-param instruction element
 *
 * Processes an xsl:with-param instruction at transformation time.
 * The value is compute, but not recorded.
 * NOTE that this is also called with an *xsl:param* element
 * from exsltFuncFunctionFunction(). 
 *
 * Returns the new xsltStackElemPtr or NULL
 */

xsltStackElemPtr
xsltParseStylesheetCallerParam(xsltTransformContextPtr ctxt, xmlNodePtr inst)
{
#ifdef XSLT_REFACTORED
    xsltStyleBasicItemVariablePtr comp;
#else
    xsltStylePreCompPtr comp;
#endif
    xmlNodePtr tree = NULL; /* The first child node of the instruction or
                               the instruction itself. */
    xsltStackElemPtr param = NULL;
    
    if ((ctxt == NULL) || (inst == NULL))
        return(NULL);

#ifdef XSLT_REFACTORED
    comp = (xsltStyleBasicItemVariablePtr) inst->psvi;
#else
    comp = (xsltStylePreCompPtr) inst->psvi;
#endif
    
    if (comp == NULL) {
        xsltTransformError(ctxt, NULL, inst,
            "Internal error in xsltParseStylesheetCallerParam(): "
            "The XSLT 'with-param' instruction was not compiled.\n");
        return(NULL);
    }
    if (comp->name == NULL) {
        xsltTransformError(ctxt, NULL, inst,
            "Internal error in xsltParseStylesheetCallerParam(): "
            "XSLT 'with-param': The attribute 'name' was not compiled.\n");
        return(NULL);
    }

#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
            "Handling xsl:with-param %s\n", comp->name));
#endif

    if (comp->select == NULL) {
        tree = inst->children;
    } else {
#ifdef WITH_XSLT_DEBUG_VARIABLE
        XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
            "        select %s\n", comp->select));
#endif
        tree = inst;
    }

    param = xsltBuildVariable(ctxt, (xsltStylePreCompPtr) comp, tree);

    return(param);
}

/**
 * xsltParseGlobalVariable:
 * @style:  the XSLT stylesheet
 * @cur:  the "variable" element
 *
 * Parses a global XSLT 'variable' declaration at compilation time
 * and registers it
 */
void
xsltParseGlobalVariable(xsltStylesheetPtr style, xmlNodePtr cur)
{
#ifdef XSLT_REFACTORED
    xsltStyleItemVariablePtr comp;
#else
    xsltStylePreCompPtr comp;
#endif

    if ((cur == NULL) || (style == NULL))
        return;
    
#ifdef XSLT_REFACTORED
    /*
    * Note that xsltStylePreCompute() will be called from
    * xslt.c only.
    */
    comp = (xsltStyleItemVariablePtr) cur->psvi;
#else
    xsltStylePreCompute(style, cur);
    comp = (xsltStylePreCompPtr) cur->psvi;
#endif
    if (comp == NULL) {
        xsltTransformError(NULL, style, cur,
             "xsl:variable : compilation failed\n");
        return;
    }

    if (comp->name == NULL) {
        xsltTransformError(NULL, style, cur,
            "xsl:variable : missing name attribute\n");
        return;
    }

    /*
    * Parse the content (a sequence constructor) of xsl:variable.
    */
    if (cur->children != NULL) {
#ifdef XSLT_REFACTORED  
        xsltParseSequenceConstructor(XSLT_CCTXT(style), cur->children);
#else
        xsltParseTemplateContent(style, cur);
#endif
    }
#ifdef WITH_XSLT_DEBUG_VARIABLE
    xsltGenericDebug(xsltGenericDebugContext,
        "Registering global variable %s\n", comp->name);
#endif

    xsltRegisterGlobalVariable(style, comp->name, comp->ns,
        comp->select, cur->children, (xsltStylePreCompPtr) comp,
        NULL);
}

/**
 * xsltParseGlobalParam:
 * @style:  the XSLT stylesheet
 * @cur:  the "param" element
 *
 * parse an XSLT transformation param declaration and record
 * its value.
 */

void
xsltParseGlobalParam(xsltStylesheetPtr style, xmlNodePtr cur) {
#ifdef XSLT_REFACTORED
    xsltStyleItemParamPtr comp;
#else
    xsltStylePreCompPtr comp;
#endif

    if ((cur == NULL) || (style == NULL))
        return;
    
#ifdef XSLT_REFACTORED
    /*
    * Note that xsltStylePreCompute() will be called from
    * xslt.c only.
    */
    comp = (xsltStyleItemParamPtr) cur->psvi;
#else
    xsltStylePreCompute(style, cur);
    comp = (xsltStylePreCompPtr) cur->psvi;
#endif    
    if (comp == NULL) {
        xsltTransformError(NULL, style, cur,
             "xsl:param : compilation failed\n");
        return;
    }

    if (comp->name == NULL) {
        xsltTransformError(NULL, style, cur,
            "xsl:param : missing name attribute\n");
        return;
    }

    /*
    * Parse the content (a sequence constructor) of xsl:param.
    */
    if (cur->children != NULL) {
#ifdef XSLT_REFACTORED  
        xsltParseSequenceConstructor(XSLT_CCTXT(style), cur->children);
#else
        xsltParseTemplateContent(style, cur);
#endif
    }

#ifdef WITH_XSLT_DEBUG_VARIABLE
    xsltGenericDebug(xsltGenericDebugContext,
        "Registering global param %s\n", comp->name);
#endif

    xsltRegisterGlobalVariable(style, comp->name, comp->ns,
        comp->select, cur->children, (xsltStylePreCompPtr) comp,
        NULL);
}

/**
 * xsltParseStylesheetVariable:
 * @ctxt:  the XSLT transformation context
 * @inst:  the xsl:variable instruction element
 *
 * Registers a local XSLT 'variable' instruction at transformation time
 * and evaluates its value.
 */
void
xsltParseStylesheetVariable(xsltTransformContextPtr ctxt, xmlNodePtr inst)
{
#ifdef XSLT_REFACTORED
    xsltStyleItemVariablePtr comp;
#else
    xsltStylePreCompPtr comp;
#endif

    if ((inst == NULL) || (ctxt == NULL))
        return;

    comp = inst->psvi;
    if (comp == NULL) {
        xsltTransformError(ctxt, NULL, inst,
            "Internal error in xsltParseStylesheetVariable(): "
            "The XSLT 'variable' instruction was not compiled.\n");
        return;
    }
    if (comp->name == NULL) {
        xsltTransformError(ctxt, NULL, inst,
            "Internal error in xsltParseStylesheetVariable(): "
            "The attribute 'name' was not compiled.\n");
        return;
    }

#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
        "Registering variable '%s'\n", comp->name));
#endif

    xsltRegisterVariable(ctxt, (xsltStylePreCompPtr) comp, inst->children, 0);
}

/**
 * xsltParseStylesheetParam:
 * @ctxt:  the XSLT transformation context
 * @cur:  the XSLT 'param' element
 *
 * Registers a local XSLT 'param' declaration at transformation time and
 * evaluates its value.
 */
void
xsltParseStylesheetParam(xsltTransformContextPtr ctxt, xmlNodePtr cur)
{
#ifdef XSLT_REFACTORED
    xsltStyleItemParamPtr comp;
#else
    xsltStylePreCompPtr comp;
#endif

    if ((cur == NULL) || (ctxt == NULL))
        return;

    comp = cur->psvi;
    if ((comp == NULL) || (comp->name == NULL)) {
        xsltTransformError(ctxt, NULL, cur,
            "Internal error in xsltParseStylesheetParam(): "
            "The XSLT 'param' declaration was not compiled correctly.\n");
        return;
    }

#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
        "Registering param %s\n", comp->name));
#endif

    xsltRegisterVariable(ctxt, (xsltStylePreCompPtr) comp, cur->children, 1);
}

/**
 * xsltFreeGlobalVariables:
 * @ctxt:  the XSLT transformation context
 *
 * Free up the data associated to the global variables
 * its value.
 */

void
xsltFreeGlobalVariables(xsltTransformContextPtr ctxt) {
    xmlHashFree(ctxt->globalVars, (xmlHashDeallocator) xsltFreeStackElem);
}

/**
 * xsltXPathVariableLookup:
 * @ctxt:  a void * but the the XSLT transformation context actually
 * @name:  the variable name
 * @ns_uri:  the variable namespace URI
 *
 * This is the entry point when a varibale is needed by the XPath
 * interpretor.
 *
 * Returns the value or NULL if not found
 */
xmlXPathObjectPtr
xsltXPathVariableLookup(void *ctxt, const xmlChar *name,
                        const xmlChar *ns_uri) {
    xsltTransformContextPtr tctxt;
    xmlXPathObjectPtr valueObj = NULL;

    if ((ctxt == NULL) || (name == NULL))
        return(NULL);

#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(((xsltTransformContextPtr)ctxt),XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
            "Lookup variable '%s'\n", name));
#endif
    
    tctxt = (xsltTransformContextPtr) ctxt;
    /*
    * Local variables/params ---------------------------------------------
    *
    * Do the lookup from the top of the stack, but
    * don't use params being computed in a call-param
    * First lookup expects the variable name and URI to
    * come from the disctionnary and hence pointer comparison.
    */
    if (tctxt->varsNr != 0) {
        int i;
        xsltStackElemPtr variable = NULL, cur;

        for (i = tctxt->varsNr; i > tctxt->varsBase; i--) {
            cur = tctxt->varsTab[i-1];
            if ((cur->name == name) && (cur->nameURI == ns_uri)) {
#if 0
                stack_addr++;
#endif
                variable = cur;
                goto local_variable_found;
            }
            cur = cur->next;
        }       
        /*
        * Redo the lookup with interned strings to avoid string comparison.
        *
        * OPTIMIZE TODO: The problem here is, that if we request a
        *  global variable, then this will be also executed.
        */
        {
            const xmlChar *tmpName = name, *tmpNsName = ns_uri;

            name = xmlDictLookup(tctxt->dict, name, -1);
            if (ns_uri)
                ns_uri = xmlDictLookup(tctxt->dict, ns_uri, -1);
            if ((tmpName != name) || (tmpNsName != ns_uri)) {           
                for (i = tctxt->varsNr; i > tctxt->varsBase; i--) {
                    cur = tctxt->varsTab[i-1];
                    if ((cur->name == name) && (cur->nameURI == ns_uri)) {
#if 0
                        stack_cmp++;
#endif
                        variable = cur;
                        goto local_variable_found;
                    }
                }
            }
        }

local_variable_found:

        if (variable) {
            if (variable->computed == 0) {
                
#ifdef WITH_XSLT_DEBUG_VARIABLE
                XSLT_TRACE(tctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                    "uncomputed variable '%s'\n", name));
#endif
                variable->value = xsltEvalVariable(tctxt, variable, NULL);
                variable->computed = 1;
            }
            if (variable->value != NULL) {
                valueObj = xmlXPathObjectCopy(variable->value); 
            }
            return(valueObj);
        }
    }
    /*
    * Global variables/params --------------------------------------------
    */    
    if (tctxt->globalVars) {
        valueObj = xsltGlobalVariableLookup(tctxt, name, ns_uri);
    }

    if (valueObj == NULL) {

#ifdef WITH_XSLT_DEBUG_VARIABLE
    XSLT_TRACE(tctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                     "variable not found '%s'\n", name));
#endif

        if (ns_uri) {
            xsltTransformError(tctxt, NULL, tctxt->inst,
                "Variable '{%s}%s' has not been declared.\n", ns_uri, name);
        } else {
            xsltTransformError(tctxt, NULL, tctxt->inst,
                "Variable '%s' has not been declared.\n", name);
        }
    } else {

#ifdef WITH_XSLT_DEBUG_VARIABLE
        XSLT_TRACE(tctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
            "found variable '%s'\n", name));
#endif
    }

    return(valueObj);
}