templates.c

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/*
 * templates.c: Implementation of the template processing
 *
 * 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/globals.h>
#include <libxml/xmlerror.h>
#include <libxml/tree.h>
#include <libxml/xpathInternals.h>
#include <libxml/parserInternals.h>
#include "xslt.h"
#include "xsltInternals.h"
#include "xsltutils.h"
#include "variables.h"
#include "functions.h"
#include "templates.h"
#include "transform.h"
#include "namespaces.h"
#include "attributes.h"

#ifdef WITH_XSLT_DEBUG
#define WITH_XSLT_DEBUG_TEMPLATES
#endif

/************************************************************************
 *                                  *
 *          Module interfaces               *
 *                                  *
 ************************************************************************/
 
int
xsltEvalXPathPredicate(xsltTransformContextPtr ctxt, xmlXPathCompExprPtr comp,
               xmlNsPtr *nsList, int nsNr) {
    int ret;
    xmlXPathObjectPtr res;
    int oldNsNr;
    xmlNsPtr *oldNamespaces;
    xmlNodePtr oldInst;
    int oldProximityPosition, oldContextSize;

    oldContextSize = ctxt->xpathCtxt->contextSize;
    oldProximityPosition = ctxt->xpathCtxt->proximityPosition;
    oldNsNr = ctxt->xpathCtxt->nsNr;
    oldNamespaces = ctxt->xpathCtxt->namespaces;
    oldInst = ctxt->inst;

    ctxt->xpathCtxt->node = ctxt->node;
    ctxt->xpathCtxt->namespaces = nsList;
    ctxt->xpathCtxt->nsNr = nsNr;

    res = xmlXPathCompiledEval(comp, ctxt->xpathCtxt);

    if (res != NULL) {
    ret = xmlXPathEvalPredicate(ctxt->xpathCtxt, res);
    xmlXPathFreeObject(res);
#ifdef WITH_XSLT_DEBUG_TEMPLATES
    XSLT_TRACE(ctxt,XSLT_TRACE_TEMPLATES,xsltGenericDebug(xsltGenericDebugContext,
         "xsltEvalXPathPredicate: returns %d\n", ret));
#endif
    } else {
#ifdef WITH_XSLT_DEBUG_TEMPLATES
    XSLT_TRACE(ctxt,XSLT_TRACE_TEMPLATES,xsltGenericDebug(xsltGenericDebugContext,
         "xsltEvalXPathPredicate: failed\n"));
#endif
    ctxt->state = XSLT_STATE_STOPPED;
    ret = 0;
    }
    ctxt->xpathCtxt->nsNr = oldNsNr;

    ctxt->xpathCtxt->namespaces = oldNamespaces;
    ctxt->inst = oldInst;
    ctxt->xpathCtxt->contextSize = oldContextSize;
    ctxt->xpathCtxt->proximityPosition = oldProximityPosition;

    return(ret);
}

xmlChar *
xsltEvalXPathStringNs(xsltTransformContextPtr ctxt, xmlXPathCompExprPtr comp,
                  int nsNr, xmlNsPtr *nsList) {
    xmlChar *ret = NULL;
    xmlXPathObjectPtr res;
    xmlNodePtr oldInst;
    xmlNodePtr oldNode;
    int oldPos, oldSize;
    int oldNsNr;
    xmlNsPtr *oldNamespaces;

    oldInst = ctxt->inst;
    oldNode = ctxt->node;
    oldPos = ctxt->xpathCtxt->proximityPosition;
    oldSize = ctxt->xpathCtxt->contextSize;
    oldNsNr = ctxt->xpathCtxt->nsNr;
    oldNamespaces = ctxt->xpathCtxt->namespaces;

    ctxt->xpathCtxt->node = ctxt->node;
    /* TODO: do we need to propagate the namespaces here ? */
    ctxt->xpathCtxt->namespaces = nsList;
    ctxt->xpathCtxt->nsNr = nsNr;
    res = xmlXPathCompiledEval(comp, ctxt->xpathCtxt);
    if (res != NULL) {
    if (res->type != XPATH_STRING)
        res = xmlXPathConvertString(res);
    if (res->type == XPATH_STRING) {
            ret = res->stringval;
        res->stringval = NULL;
    } else {
        xsltTransformError(ctxt, NULL, NULL,
         "xpath : string() function didn't return a String\n");
    }
    xmlXPathFreeObject(res);
    } else {
    ctxt->state = XSLT_STATE_STOPPED;
    }
#ifdef WITH_XSLT_DEBUG_TEMPLATES
    XSLT_TRACE(ctxt,XSLT_TRACE_TEMPLATES,xsltGenericDebug(xsltGenericDebugContext,
     "xsltEvalXPathString: returns %s\n", ret));
#endif
    ctxt->inst = oldInst;
    ctxt->node = oldNode;
    ctxt->xpathCtxt->contextSize = oldSize;
    ctxt->xpathCtxt->proximityPosition = oldPos;
    ctxt->xpathCtxt->nsNr = oldNsNr;
    ctxt->xpathCtxt->namespaces = oldNamespaces;
    return(ret);
}

xmlChar *
xsltEvalXPathString(xsltTransformContextPtr ctxt, xmlXPathCompExprPtr comp) {
    return(xsltEvalXPathStringNs(ctxt, comp, 0, NULL));
}

xmlChar *
xsltEvalTemplateString(xsltTransformContextPtr ctxt,
               xmlNodePtr contextNode,
                   xmlNodePtr inst)
{
    xmlNodePtr oldInsert, insert = NULL;
    xmlChar *ret;

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

    if (inst->children == NULL)
    return(NULL);

    /*
    * This creates a temporary element-node to add the resulting
    * text content to.
    * OPTIMIZE TODO: Keep such an element-node in the transformation
    *  context to avoid creating it every time.
    */
    insert = xmlNewDocNode(ctxt->output, NULL,
                       (const xmlChar *)"fake", NULL);
    if (insert == NULL) {
    xsltTransformError(ctxt, NULL, contextNode,
        "Failed to create temporary node\n");
    return(NULL);
    }
    oldInsert = ctxt->insert;
    ctxt->insert = insert;
    /*
    * OPTIMIZE TODO: if inst->children consists only of text-nodes.
    */
    xsltApplyOneTemplate(ctxt, contextNode, inst->children, NULL, NULL);

    ctxt->insert = oldInsert;

    ret = xmlNodeGetContent(insert);
    if (insert != NULL)
    xmlFreeNode(insert);
    return(ret);
}

xmlChar *
xsltAttrTemplateValueProcessNode(xsltTransformContextPtr ctxt,
      const xmlChar *str, xmlNodePtr inst)
{
    xmlChar *ret = NULL;
    const xmlChar *cur;
    xmlChar *expr, *val;
    xmlNsPtr *nsList = NULL;
    int nsNr = 0;

    if (str == NULL) return(NULL);
    if (*str == 0)
    return(xmlStrndup((xmlChar *)"", 0));

    cur = str;
    while (*cur != 0) {
    if (*cur == '{') {
        if (*(cur+1) == '{') {  /* escaped '{' */
            cur++;
        ret = xmlStrncat(ret, str, cur - str);
        cur++;
        str = cur;
        continue;
        }
        ret = xmlStrncat(ret, str, cur - str);
        str = cur;
        cur++;
        while ((*cur != 0) && (*cur != '}')) cur++;
        if (*cur == 0) {
            xsltTransformError(ctxt, NULL, inst,
            "xsltAttrTemplateValueProcessNode: unmatched '{'\n");
        ret = xmlStrncat(ret, str, cur - str);
        return(ret);
        }
        str++;
        expr = xmlStrndup(str, cur - str);
        if (expr == NULL)
        return(ret);
        else if (*expr == '{') {
        ret = xmlStrcat(ret, expr);
        xmlFree(expr);
        } else {
        xmlXPathCompExprPtr comp;
        /*
         * TODO: keep precompiled form around
         */
        if ((nsList == NULL) && (inst != NULL)) {
            int i = 0;

            nsList = xmlGetNsList(inst->doc, inst);
            if (nsList != NULL) {
            while (nsList[i] != NULL)
                i++;
            nsNr = i;
            }
        }
        comp = xmlXPathCompile(expr);
                val = xsltEvalXPathStringNs(ctxt, comp, nsNr, nsList);
        xmlXPathFreeCompExpr(comp);
        xmlFree(expr);
        if (val != NULL) {
            ret = xmlStrcat(ret, val);
            xmlFree(val);
        }
        }
        cur++;
        str = cur;
    } else if (*cur == '}') {
        cur++;
        if (*cur == '}') {  /* escaped '}' */
        ret = xmlStrncat(ret, str, cur - str);
        cur++;
        str = cur;
        continue;
        } else {
            xsltTransformError(ctxt, NULL, inst,
             "xsltAttrTemplateValueProcessNode: unmatched '}'\n");
        }
    } else
        cur++;
    }
    if (cur != str) {
    ret = xmlStrncat(ret, str, cur - str);
    }

    if (nsList != NULL)
    xmlFree(nsList);

    return(ret);
}

xmlChar *
xsltAttrTemplateValueProcess(xsltTransformContextPtr ctxt, const xmlChar *str) {
    return(xsltAttrTemplateValueProcessNode(ctxt, str, NULL));
}

xmlChar *
xsltEvalAttrValueTemplate(xsltTransformContextPtr ctxt, xmlNodePtr inst,
                      const xmlChar *name, const xmlChar *ns)
{
    xmlChar *ret;
    xmlChar *expr;

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

    expr = xsltGetNsProp(inst, name, ns);
    if (expr == NULL)
    return(NULL);

    /*
     * TODO: though now {} is detected ahead, it would still be good to
     *       optimize both functions to keep the splitted value if the
     *       attribute content and the XPath precompiled expressions around
     */

    ret = xsltAttrTemplateValueProcessNode(ctxt, expr, inst);
#ifdef WITH_XSLT_DEBUG_TEMPLATES
    XSLT_TRACE(ctxt,XSLT_TRACE_TEMPLATES,xsltGenericDebug(xsltGenericDebugContext,
     "xsltEvalAttrValueTemplate: %s returns %s\n", expr, ret));
#endif
    if (expr != NULL)
    xmlFree(expr);
    return(ret);
}

const xmlChar *
xsltEvalStaticAttrValueTemplate(xsltStylesheetPtr style, xmlNodePtr inst,
            const xmlChar *name, const xmlChar *ns, int *found) {
    const xmlChar *ret;
    xmlChar *expr;

    if ((style == NULL) || (inst == NULL) || (name == NULL))
    return(NULL);

    expr = xsltGetNsProp(inst, name, ns);
    if (expr == NULL) {
    *found = 0;
    return(NULL);
    }
    *found = 1;

    ret = xmlStrchr(expr, '{');
    if (ret != NULL) {
    xmlFree(expr);
    return(NULL);
    }
    ret = xmlDictLookup(style->dict, expr, -1);
    xmlFree(expr);
    return(ret);
}

xmlAttrPtr
xsltAttrTemplateProcess(xsltTransformContextPtr ctxt, xmlNodePtr target,
                    xmlAttrPtr attr)
{
    const xmlChar *value;
    xmlAttrPtr ret;

    if ((ctxt == NULL) || (attr == NULL) || (target == NULL))
    return(NULL);
    
    if (attr->type != XML_ATTRIBUTE_NODE)
    return(NULL);

    /*
    * Skip all XSLT attributes.
    */
#ifdef XSLT_REFACTORED    
    if (attr->psvi == xsltXSLTAttrMarker)
    return(NULL);
#else
    if ((attr->ns != NULL) && xmlStrEqual(attr->ns->href, XSLT_NAMESPACE))
    return(NULL);
#endif
    /*
    * Get the value.
    */
    if (attr->children != NULL) {
    if ((attr->children->type != XML_TEXT_NODE) ||
        (attr->children->next != NULL))
    {
        xsltTransformError(ctxt, NULL, attr->parent,
        "Internal error: The children of an attribute node of a "
        "literal result element are not in the expected form.\n");
        return(NULL);
    }
    value = attr->children->content;
    if (value == NULL)
        value = xmlDictLookup(ctxt->dict, BAD_CAST "", 0);
    } else
    value = xmlDictLookup(ctxt->dict, BAD_CAST "", 0);
    /*
    * Overwrite duplicates.
    */
    ret = target->properties;
    while (ret != NULL) {
        if (((attr->ns != NULL) == (ret->ns != NULL)) &&
        xmlStrEqual(ret->name, attr->name) &&
        ((attr->ns == NULL) || xmlStrEqual(ret->ns->href, attr->ns->href)))
    {
        break;
    }
        ret = ret->next;
    }
    if (ret != NULL) {  
        /* free the existing value */
    xmlFreeNodeList(ret->children);
    ret->children = ret->last = NULL;
    /*
    * Adjust ns-prefix if needed.
    */
    if ((ret->ns != NULL) &&
        (! xmlStrEqual(ret->ns->prefix, attr->ns->prefix)))
    {
        ret->ns = xsltGetNamespace(ctxt, attr->parent, attr->ns, target);
    }
    } else {
        /* create a new attribute */
    if (attr->ns != NULL)
        ret = xmlNewNsProp(target,
        xsltGetNamespace(ctxt, attr->parent, attr->ns, target),
            attr->name, NULL);
    else
        ret = xmlNewNsProp(target, NULL, attr->name, NULL); 
    }
    /*
    * Set the value.
    */
    if (ret != NULL) {
        xmlNodePtr text;

        text = xmlNewText(NULL);
    if (text != NULL) {
        ret->last = ret->children = text;
        text->parent = (xmlNodePtr) ret;
        text->doc = ret->doc;

        if (attr->psvi != NULL) {
        /*
        * Evaluate the Attribute Value Template.
        */
        xmlChar *val;
        val = xsltEvalAVT(ctxt, attr->psvi, attr->parent);
        if (val == NULL) {
            /*
            * TODO: Damn, we need an easy mechanism to report
            * qualified names!
            */
            if (attr->ns) {
            xsltTransformError(ctxt, NULL, attr->parent,
                "Internal error: Failed to evaluate the AVT "
                "of attribute '{%s}%s'.\n",
                attr->ns->href, attr->name);
            } else {
            xsltTransformError(ctxt, NULL, attr->parent,
                "Internal error: Failed to evaluate the AVT "
                "of attribute '%s'.\n",
                attr->name);
            }
            text->content = xmlStrdup(BAD_CAST "");
        } else {
            text->content = val;
        }
        } else if ((ctxt->internalized) && (target != NULL) &&
                   (target->doc != NULL) &&
               (target->doc->dict == ctxt->dict)) {
        text->content = (xmlChar *) value;
        } else {
        text->content = xmlStrdup(value);
        }
    }
    } else {
    if (attr->ns) {
        xsltTransformError(ctxt, NULL, attr->parent,
            "Internal error: Failed to create attribute '{%s}%s'.\n",
        attr->ns->href, attr->name);
    } else {
        xsltTransformError(ctxt, NULL, attr->parent,
            "Internal error: Failed to create attribute '%s'.\n",
        attr->name);
    }
    }
    return(ret);
}


xmlAttrPtr
xsltAttrListTemplateProcess(xsltTransformContextPtr ctxt, 
                        xmlNodePtr target, xmlAttrPtr attrs)
{
    xmlAttrPtr attr, copy, last;
    xmlNodePtr oldInsert, text;
    xmlNsPtr origNs = NULL, copyNs = NULL;
    const xmlChar *value;
    xmlChar *valueAVT;

    if ((ctxt == NULL) || (target == NULL) || (attrs == NULL))
    return(NULL);

    oldInsert = ctxt->insert;
    ctxt->insert = target;        

    /*
    * Instantiate LRE-attributes.
    */
    if (target->properties) {
    last = target->properties;
    while (last->next != NULL)
        last = last->next;
    } else {
    last = NULL;
    }
    attr = attrs;
    do {
    /*
    * Skip XSLT attributes.
    */
#ifdef XSLT_REFACTORED
    if (attr->psvi == xsltXSLTAttrMarker) {
        goto next_attribute;
    }
#else
    if ((attr->ns != NULL) &&
        xmlStrEqual(attr->ns->href, XSLT_NAMESPACE))
    {
        goto next_attribute;
    }
#endif
    /*
    * Get the value.
    */
    if (attr->children != NULL) {
        if ((attr->children->type != XML_TEXT_NODE) ||
        (attr->children->next != NULL))
        {
        xsltTransformError(ctxt, NULL, attr->parent,
            "Internal error: The children of an attribute node of a "
            "literal result element are not in the expected form.\n");
        goto error;
        }
        value = attr->children->content;
        if (value == NULL)
        value = xmlDictLookup(ctxt->dict, BAD_CAST "", 0);
    } else
        value = xmlDictLookup(ctxt->dict, BAD_CAST "", 0);

    /*
    * Create a new attribute.
    */
    copy = xmlNewDocProp(target->doc, attr->name, NULL);
    if (copy == NULL) {
        if (attr->ns) {
        xsltTransformError(ctxt, NULL, attr->parent,
            "Internal error: Failed to create attribute '{%s}%s'.\n",
            attr->ns->href, attr->name);
        } else {
        xsltTransformError(ctxt, NULL, attr->parent,
            "Internal error: Failed to create attribute '%s'.\n",
            attr->name);
        }
        goto error;
    }
    /*
    * Attach it to the target element.
    */
    copy->parent = target;
    if (last == NULL) {
        target->properties = copy;
        last = copy;
    } else {
        last->next = copy;
        copy->prev = last;
        last = copy;
    }
    /*
    * Set the namespace. Avoid lookups of same namespaces.
    */
    if (attr->ns != origNs) {
        origNs = attr->ns;
        if (attr->ns != NULL) {
#ifdef XSLT_REFACTORED
        copyNs = xsltGetSpecialNamespace(ctxt, attr->parent,
            attr->ns->href, attr->ns->prefix, target);
#else
        copyNs = xsltGetNamespace(ctxt, attr->parent,
            attr->ns, target);
#endif
        if (copyNs == NULL)
            goto error;
        } else
        copyNs = NULL;
    }
    copy->ns = copyNs;

    /*
    * Set the value.
    */
    text = xmlNewText(NULL);
    if (text != NULL) {
        copy->last = copy->children = text;
        text->parent = (xmlNodePtr) copy;
        text->doc = copy->doc;

        if (attr->psvi != NULL) {
        /*
        * Evaluate the Attribute Value Template.
        */
        valueAVT = xsltEvalAVT(ctxt, attr->psvi, attr->parent);
        if (valueAVT == NULL) {
            /*
            * TODO: Damn, we need an easy mechanism to report
            * qualified names!
            */
            if (attr->ns) {
            xsltTransformError(ctxt, NULL, attr->parent,
                "Internal error: Failed to evaluate the AVT "
                "of attribute '{%s}%s'.\n",
                attr->ns->href, attr->name);
            } else {
            xsltTransformError(ctxt, NULL, attr->parent,
                "Internal error: Failed to evaluate the AVT "
                "of attribute '%s'.\n",
                attr->name);
            }
            text->content = xmlStrdup(BAD_CAST "");
            goto error;
        } else {
            text->content = valueAVT;
        }
        } else if ((ctxt->internalized) &&
        (target->doc != NULL) &&
        (target->doc->dict == ctxt->dict))
        {
        text->content = (xmlChar *) value;
        } else {
        text->content = xmlStrdup(value);
        }
            if ((copy != NULL) && (text != NULL) &&
                (xmlIsID(copy->doc, copy->parent, copy)))
                xmlAddID(NULL, copy->doc, text->content, copy);
    }

next_attribute:
    attr = attr->next;
    } while (attr != NULL);

    /*
    * Apply attribute-sets.
    * The creation of such attributes will not overwrite any existing
    * attribute.
    */
    attr = attrs;
    do {
#ifdef XSLT_REFACTORED
    if ((attr->psvi == xsltXSLTAttrMarker) &&
        xmlStrEqual(attr->name, (const xmlChar *)"use-attribute-sets"))
    {
        xsltApplyAttributeSet(ctxt, ctxt->node, (xmlNodePtr) attr, NULL);
    }
#else
    if ((attr->ns != NULL) &&
        xmlStrEqual(attr->name, (const xmlChar *)"use-attribute-sets") &&
        xmlStrEqual(attr->ns->href, XSLT_NAMESPACE))
    {
        xsltApplyAttributeSet(ctxt, ctxt->node, (xmlNodePtr) attr, NULL);
    }
#endif
    attr = attr->next;
    } while (attr != NULL);

    ctxt->insert = oldInsert;
    return(target->properties);

error:
    ctxt->insert = oldInsert;
    return(NULL);
}


xmlNodePtr *
xsltTemplateProcess(xsltTransformContextPtr ctxt ATTRIBUTE_UNUSED, xmlNodePtr node) {
    if (node == NULL)
    return(NULL);
    
    return(0);
}