variables.c

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/*
 * 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
 */

#include "precomp.h"

#ifdef WITH_XSLT_DEBUG
 #define WITH_XSLT_DEBUG_VARIABLE
#endif

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

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

#define XSLT_VAR_GLOBAL (1<<0)
#define XSLT_VAR_IN_SELECT (1<<1)
#define XSLT_TCTXT_VARIABLE(c) ((xsltStackElemPtr) (c)->contextVariable)

/************************************************************************
 *                                  *
 *  Result Value Tree (Result Tree Fragment) interfaces         *
 *                                  *
 ************************************************************************/
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);
}

int
xsltRegisterTmpRVT(xsltTransformContextPtr ctxt, xmlDocPtr RVT)
{
    if ((ctxt == NULL) || (RVT == NULL))
    return(-1);

    RVT->prev = NULL;
    RVT->psvi = XSLT_RVT_LOCAL;

    /*
    * 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);
}

int
xsltRegisterLocalRVT(xsltTransformContextPtr ctxt,
             xmlDocPtr RVT)
{
    if ((ctxt == NULL) || (RVT == NULL))
    return(-1);

    RVT->prev = NULL;
    RVT->psvi = XSLT_RVT_LOCAL;

    /*
    * When evaluating "select" expressions of xsl:variable
    * and xsl:param, we need to bind newly created tree fragments
    * to the variable itself; otherwise the fragment 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;
    return(0);
}

int
xsltExtensionInstructionResultFinalize(
        xsltTransformContextPtr ctxt ATTRIBUTE_UNUSED)
{
    xmlGenericError(xmlGenericErrorContext,
            "xsltExtensionInstructionResultFinalize is unsupported "
            "in this release of libxslt.\n");
    return(-1);
}

int
xsltExtensionInstructionResultRegister(
        xsltTransformContextPtr ctxt ATTRIBUTE_UNUSED,
    xmlXPathObjectPtr obj ATTRIBUTE_UNUSED)
{
    return(0);
}

int
xsltFlagRVTs(xsltTransformContextPtr ctxt, xmlXPathObjectPtr obj, void *val) {
    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 xsltFlagRVTs(): "
            "Cannot retrieve the doc of a namespace node.\n");
        return(-1);
        }
    } else {
        doc = cur->doc;
    }
    if (doc == NULL) {
        xsltTransformError(ctxt, NULL, ctxt->inst,
        "Internal error in xsltFlagRVTs(): "
        "Cannot retrieve the doc of a node.\n");
        return(-1);
    }
    if (doc->name && (doc->name[0] == ' ') &&
            doc->psvi != XSLT_RVT_GLOBAL) {
        /*
        * This is a result tree fragment.
        * We store ownership information in the @psvi field.
        * TODO: How do we know if this is a doc acquired via the
        *  document() function?
        */
#ifdef WITH_XSLT_DEBUG_VARIABLE
            XSLT_TRACE(ctxt,XSLT_TRACE_VARIABLES,xsltGenericDebug(xsltGenericDebugContext,
                "Flagging RVT %p: %p -> %p\n", doc, doc->psvi, val));
#endif

            if (val == XSLT_RVT_LOCAL) {
                if (doc->psvi == XSLT_RVT_FUNC_RESULT)
                    doc->psvi = XSLT_RVT_LOCAL;
            } else if (val == XSLT_RVT_GLOBAL) {
                if (doc->psvi != XSLT_RVT_LOCAL) {
            xmlGenericError(xmlGenericErrorContext,
                            "xsltFlagRVTs: Invalid transition %p => GLOBAL\n",
                            doc->psvi);
                    doc->psvi = XSLT_RVT_GLOBAL;
                    return(-1);
                }

                /* Will be registered as persistant in xsltReleaseLocalRVTs. */
                doc->psvi = XSLT_RVT_GLOBAL;
            } else if (val == XSLT_RVT_FUNC_RESULT) {
            doc->psvi = val;
            }
    }
    }

    return(0);
}

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 ownership information.
    */
    RVT->psvi = NULL;

    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);
}

int
xsltRegisterPersistRVT(xsltTransformContextPtr ctxt, xmlDocPtr RVT)
{
    if ((ctxt == NULL) || (RVT == NULL)) return(-1);

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

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               *
 *                                  *
 ************************************************************************/

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);
}

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);
}

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->context) {
    xmlDocPtr cur;

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

            if (cur->psvi == XSLT_RVT_LOCAL) {
        xsltReleaseRVT(elem->context, cur);
            } else if (cur->psvi == XSLT_RVT_FUNC_RESULT) {
                xsltRegisterLocalRVT(elem->context, cur);
                cur->psvi = XSLT_RVT_FUNC_RESULT;
            } else {
                xmlGenericError(xmlGenericErrorContext,
                        "xsltFreeStackElem: Unexpected RVT flag %p\n",
                        cur->psvi);
            }
    }
    }
    /*
    * 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);
}

static void
xsltFreeStackElemEntry(void *payload, const xmlChar *name ATTRIBUTE_UNUSED) {
    xsltFreeStackElem((xsltStackElemPtr) payload);
}


void
xsltFreeStackElemList(xsltStackElemPtr elem) {
    xsltStackElemPtr next;

    while (elem != NULL) {
    next = elem->next;
    xsltFreeStackElem(elem);
    elem = next;
    }
}

#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);
}

#ifdef XSLT_REFACTORED
#else

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);
}

#endif /* XSLT_REFACTORED */

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);
}

int
xsltAddStackElemList(xsltTransformContextPtr ctxt, xsltStackElemPtr elems)
{
    return(xsltAddStackElem(ctxt, elems));
}

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

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 = xmlXPathCtxtCompile(ctxt->xpathCtxt, 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;
                container->psvi = XSLT_RVT_LOCAL;

        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);
}

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;
#ifdef XSLT_REFACTORED
    comp = (xsltStyleBasicItemVariablePtr) elem->comp;
#else
    comp = elem->comp;
#endif
    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 = xmlXPathCtxtCompile(ctxt->xpathCtxt, 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;
            goto error;
        }

        /*
         * Mark all RVTs that are referenced from result as part
         * of this variable so they won't be freed too early.
         */
        xsltFlagRVTs(ctxt, result, XSLT_RVT_GLOBAL);

#ifdef WITH_XSLT_DEBUG_VARIABLE
#ifdef LIBXML_DEBUG_ENABLED
    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);
}

static void
xsltEvalGlobalVariableWrapper(void *payload, void *data,
                              const xmlChar *name ATTRIBUTE_UNUSED) {
    xsltEvalGlobalVariable((xsltStackElemPtr) payload,
                           (xsltTransformContextPtr) data);
}

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, xsltEvalGlobalVariableWrapper, ctxt);

    return(0);
}

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);
}

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
     */
    href = NULL;

    if (name[0] == '{') {
        int len = 0;

        while ((name[len] != 0) && (name[len] != '}')) len++;
        if (name[len] == 0) {
           xsltTransformError(ctxt, style, NULL,
           "user param : malformed parameter name : %s\n", name);
        } else {
           href = xmlDictLookup(ctxt->dict, &name[1], len-1);
           name = xmlDictLookup(ctxt->dict, &name[len + 1], -1);
       }
    }
    else {
        name = xsltSplitQName(ctxt->dict, name, &prefix);
        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 = xmlXPathCtxtCompile(ctxt->xpathCtxt, 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);
}

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;
}

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;
}

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

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

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);
    elem->computed = 1;
    return(elem);
}

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);
}

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));
}

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);
}

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) || (inst->type != XML_ELEMENT_NODE))
    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);
}

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

    if ((cur == NULL) || (style == NULL) || (cur->type != XML_ELEMENT_NODE))
    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);
}

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

    if ((cur == NULL) || (style == NULL) || (cur->type != XML_ELEMENT_NODE))
    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);
}

void
xsltParseStylesheetVariable(xsltTransformContextPtr ctxt, xmlNodePtr inst)
{
#ifdef XSLT_REFACTORED
    xsltStyleItemVariablePtr comp;
#else
    xsltStylePreCompPtr comp;
#endif

    if ((inst == NULL) || (ctxt == NULL) || (inst->type != XML_ELEMENT_NODE))
    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);
}

void
xsltParseStylesheetParam(xsltTransformContextPtr ctxt, xmlNodePtr cur)
{
#ifdef XSLT_REFACTORED
    xsltStyleItemParamPtr comp;
#else
    xsltStylePreCompPtr comp;
#endif

    if ((cur == NULL) || (ctxt == NULL) || (cur->type != XML_ELEMENT_NODE))
    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);
}

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

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);
}