/*

 * attrvt.c: Implementation of the XSL Transformation 1.0 engine

 *           attribute value template handling part.

 *

 * References:

 *   http://www.w3.org/TR/1999/REC-xslt-19991116

 *

 *   Michael Kay "XSLT Programmer's Reference" pp 637-643

 *   Writing Multiple Output Files

 *

 * 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/xpath.h>

#include <libxml/xpathInternals.h>

#include "xslt.h"

#include "xsltutils.h"

#include "xsltInternals.h"

#include "templates.h"

#ifdef WITH_XSLT_DEBUG

#define WITH_XSLT_DEBUG_AVT

#endif

#define MAX_AVT_SEG 10

typedef struct _xsltAttrVT xsltAttrVT;

typedef xsltAttrVT *xsltAttrVTPtr;

struct _xsltAttrVT {

    struct _xsltAttrVT *next; /* next xsltAttrVT */

    int nb_seg;   /* Number of segments */

    int max_seg;  /* max capacity before re-alloc needed */

    int strstart; /* is the start a string */

    /*

     * the namespaces in scope

     */

    xmlNsPtr *nsList;

    int nsNr;

    /*

     * the content is an alternate of string and xmlXPathCompExprPtr

     */

#if __STDC_VERSION__ >= 199901L

    /* Using a C99 flexible array member avoids false positives under UBSan */

    void *segments[];

#else

    void *segments[1];

#endif

};

/**

 * xsltNewAttrVT:

 * @style:  a XSLT process context

 *

 * Build a new xsltAttrVT structure

 *

 * Returns the structure or NULL in case of error

 */

static xsltAttrVTPtr

xsltNewAttrVT(xsltStylesheetPtr style) {

    xsltAttrVTPtr cur;

    size_t size = sizeof(xsltAttrVT) + MAX_AVT_SEG * sizeof(void*);

    cur = (xsltAttrVTPtr) xmlMalloc(size);

    if (cur == NULL) {

  xsltTransformError(NULL, style, NULL,

    "xsltNewAttrVTPtr : malloc failed\n");

  if (style != NULL) style->errors++;

  return(NULL);

    }

    memset(cur, 0, size);

    cur->nb_seg = 0;

    cur->max_seg = MAX_AVT_SEG;

    cur->strstart = 0;

    cur->next = style->attVTs;

    /*

     * Note: this pointer may be changed by a re-alloc within xsltCompileAttr,

     * so that code may change the stylesheet pointer also!

     */

    style->attVTs = (xsltAttrVTPtr) cur;

    return(cur);

}

/**

 * xsltFreeAttrVT:

 * @avt: pointer to an xsltAttrVT structure

 *

 * Free up the memory associated to the attribute value template

 */

static void

xsltFreeAttrVT(xsltAttrVTPtr avt) {

    int i;

    if (avt == NULL) return;

    if (avt->strstart == 1) {

  for (i = 0;i < avt->nb_seg; i += 2)

      if (avt->segments[i] != NULL)

    xmlFree((xmlChar *) avt->segments[i]);

  for (i = 1;i < avt->nb_seg; i += 2)

      xmlXPathFreeCompExpr((xmlXPathCompExprPtr) avt->segments[i]);

    } else {

  for (i = 0;i < avt->nb_seg; i += 2)

      xmlXPathFreeCompExpr((xmlXPathCompExprPtr) avt->segments[i]);

  for (i = 1;i < avt->nb_seg; i += 2)

      if (avt->segments[i] != NULL)

    xmlFree((xmlChar *) avt->segments[i]);

    }

    if (avt->nsList != NULL)

        xmlFree(avt->nsList);

    xmlFree(avt);

}

/**

 * xsltFreeAVTList:

 * @avt: pointer to an list of AVT structures

 *

 * Free up the memory associated to the attribute value templates

 */

void

xsltFreeAVTList(void *avt) {

    xsltAttrVTPtr cur = (xsltAttrVTPtr) avt, next;

    while (cur != NULL) {

        next = cur->next;

  xsltFreeAttrVT(cur);

  cur = next;

    }

}

/**

 * xsltSetAttrVTsegment:

 * @ avt: pointer to an xsltAttrVT structure

 * @ val: the value to be set to the next available segment

 *

 * Within xsltCompileAttr there are several places where a value

 * needs to be added to the 'segments' array within the xsltAttrVT

 * structure, and at each place the allocated size may have to be

 * re-allocated.  This routine takes care of that situation.

 *

 * Returns the avt pointer, which may have been changed by a re-alloc

 */

static xsltAttrVTPtr

xsltSetAttrVTsegment(xsltAttrVTPtr avt, void *val) {

    if (avt->nb_seg >= avt->max_seg) {

        size_t size = sizeof(xsltAttrVT) +

                      (avt->max_seg + MAX_AVT_SEG) * sizeof(void *);

  xsltAttrVTPtr tmp = (xsltAttrVTPtr) xmlRealloc(avt, size);

  if (tmp == NULL) {

            xsltFreeAttrVT(avt);

      return NULL;

  }

        avt = tmp;

  memset(&avt->segments[avt->nb_seg], 0, MAX_AVT_SEG*sizeof(void *));

  avt->max_seg += MAX_AVT_SEG;

    }

    avt->segments[avt->nb_seg++] = val;

    return avt;

}

/**

 * xsltCompileAttr:

 * @style:  a XSLT process context

 * @attr: the attribute coming from the stylesheet.

 *

 * Precompile an attribute in a stylesheet, basically it checks if it is

 * an attribute value template, and if yes, establish some structures needed

 * to process it at transformation time.

 */

void

xsltCompileAttr(xsltStylesheetPtr style, xmlAttrPtr attr) {

    const xmlChar *str;

    const xmlChar *cur;

    xmlChar *ret = NULL;

    xmlChar *expr = NULL;

    xsltAttrVTPtr avt;

    int i = 0, lastavt = 0;

    if ((style == NULL) || (attr == NULL) || (attr->children == NULL))

        return;

    if ((attr->children->type != XML_TEXT_NODE) ||

        (attr->children->next != NULL)) {

        xsltTransformError(NULL, style, attr->parent,

      "Attribute '%s': The content is expected to be a single text "

      "node when compiling an AVT.\n", attr->name);

  style->errors++;

  return;

    }

    str = attr->children->content;

    if ((xmlStrchr(str, '{') == NULL) &&

        (xmlStrchr(str, '}') == NULL)) return;

#ifdef WITH_XSLT_DEBUG_AVT

    xsltGenericDebug(xsltGenericDebugContext,

        "Found AVT %s: %s\n", attr->name, str);

#endif

    if (attr->psvi != NULL) {

#ifdef WITH_XSLT_DEBUG_AVT

  xsltGenericDebug(xsltGenericDebugContext,

      "AVT %s: already compiled\n", attr->name);

#endif

        return;

    }

    /*

    * Create a new AVT object.

    */

    avt = xsltNewAttrVT(style);

    if (avt == NULL)

  return;

    attr->psvi = avt;

    avt->nsList = xmlGetNsList(attr->doc, attr->parent);

    if (avt->nsList != NULL) {

  while (avt->nsList[i] != NULL)

      i++;

    }

    avt->nsNr = i;

    cur = str;

    while (*cur != 0) {

  if (*cur == '{') {

      if (*(cur+1) == '{') { /* escaped '{' */

          cur++;

    ret = xmlStrncat(ret, str, cur - str);

    cur++;

    str = cur;

    continue;

      }

      if (*(cur+1) == '}') { /* skip empty AVT */

    ret = xmlStrncat(ret, str, cur - str);

          cur += 2;

    str = cur;

    continue;

      }

      if ((ret != NULL) || (cur - str > 0)) {

    ret = xmlStrncat(ret, str, cur - str);

    str = cur;

    if (avt->nb_seg == 0)

        avt->strstart = 1;

    if ((avt = xsltSetAttrVTsegment(avt, (void *) ret)) == NULL)

        goto error;

    ret = NULL;

    lastavt = 0;

      }

      cur++;

      while ((*cur != 0) && (*cur != '}')) {

    /* Need to check for literal (bug539741) */

    if ((*cur == '\'') || (*cur == '"')) {

        char delim = *(cur++);

        while ((*cur != 0) && (*cur != delim))

      cur++;

        if (*cur != 0)

      cur++; /* skip the ending delimiter */

    } else

        cur++;

      }

      if (*cur == 0) {

          xsltTransformError(NULL, style, attr->parent,

         "Attribute '%s': The AVT has an unmatched '{'.\n",

         attr->name);

    style->errors++;

    goto error;

      }

      str++;

      expr = xmlStrndup(str, cur - str);

      if (expr == NULL) {

    /*

    * TODO: What needs to be done here?

    */

          XSLT_TODO

    goto error;

      } else {

    xmlXPathCompExprPtr comp;

    comp = xsltXPathCompile(style, expr);

    if (comp == NULL) {

        xsltTransformError(NULL, style, attr->parent,

       "Attribute '%s': Failed to compile the expression "

       "'%s' in the AVT.\n", attr->name, expr);

        style->errors++;

        goto error;

    }

    if (avt->nb_seg == 0)

        avt->strstart = 0;

    if (lastavt == 1) {

        if ((avt = xsltSetAttrVTsegment(avt, NULL)) == NULL)

            goto error;

    }

    if ((avt = xsltSetAttrVTsegment(avt, (void *) comp)) == NULL)

        goto error;

    lastavt = 1;

    xmlFree(expr);

    expr = NULL;

      }

      cur++;

      str = cur;

  } else if (*cur == '}') {

      cur++;

      if (*cur == '}') { /* escaped '}' */

    ret = xmlStrncat(ret, str, cur - str);

    cur++;

    str = cur;

    continue;

      } else {

          xsltTransformError(NULL, style, attr->parent,

         "Attribute '%s': The AVT has an unmatched '}'.\n",

         attr->name);

    goto error;

      }

  } else

      cur++;

    }

    if ((ret != NULL) || (cur - str > 0)) {

  ret = xmlStrncat(ret, str, cur - str);

  str = cur;

  if (avt->nb_seg == 0)

      avt->strstart = 1;

  if ((avt = xsltSetAttrVTsegment(avt, (void *) ret)) == NULL)

      goto error;

  ret = NULL;

    }

error:

    if (avt == NULL) {

        xsltTransformError(NULL, style, attr->parent,

    "xsltCompileAttr: malloc problem\n");

    } else {

        if (attr->psvi != avt) {  /* may have changed from realloc */

            attr->psvi = avt;

      /*

       * This is a "hack", but I can't see any clean method of

       * doing it.  If a re-alloc has taken place, then the pointer

       * for this AVT may have changed.  style->attVTs was set by

       * xsltNewAttrVT, so it needs to be re-set to the new value!

       */

      style->attVTs = avt;

  }

    }

    if (ret != NULL)

  xmlFree(ret);

    if (expr != NULL)

  xmlFree(expr);

}

/**

 * xsltEvalAVT:

 * @ctxt: the XSLT transformation context

 * @avt: the prevompiled attribute value template info

 * @node: the node hosting the attribute

 *

 * Process the given AVT, and return the new string value.

 *

 * Returns the computed string value or NULL, must be deallocated by the

 *         caller.

 */

xmlChar *

xsltEvalAVT(xsltTransformContextPtr ctxt, void *avt, xmlNodePtr node) {

    xmlChar *ret = NULL, *tmp;

    xmlXPathCompExprPtr comp;

    xsltAttrVTPtr cur = (xsltAttrVTPtr) avt;

    int i;

    int str;

    if ((ctxt == NULL) || (avt == NULL) || (node == NULL))

        return(NULL);

    str = cur->strstart;

    for (i = 0;i < cur->nb_seg;i++) {

        if (str) {

      ret = xmlStrcat(ret, (const xmlChar *) cur->segments[i]);

  } else {

      comp = (xmlXPathCompExprPtr) cur->segments[i];

      tmp = xsltEvalXPathStringNs(ctxt, comp, cur->nsNr, cur->nsList);

      if (tmp != NULL) {

          if (ret != NULL) {

        ret = xmlStrcat(ret, tmp);

        xmlFree(tmp);

    } else {

        ret = tmp;

    }

      }

  }

  str = !str;

    }

    return(ret);

}