/******************************************************************/
/*  Implementation of XML document processing using libxml2       */
/*  Author: Olivier Bertrand                2007-2013             */
/******************************************************************/
#include <string.h>
#include <stdio.h>
#include <libxml/parser.h>
#include <libxml/tree.h>
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>
//#if defined(WIN32)
//#include <windows.h>
//#else   // !WIN32
#include "my_global.h"
//#endif  // !WIN32

#if !defined(LIBXML_XPATH_ENABLED) || !defined(LIBXML_SAX1_ENABLED)
#error "XPath not supported"
#endif

#include "global.h"
#include "plgdbsem.h"
#include "xobject.h"
#include "libdoc.h"

#include "sql_string.h"

extern "C" {
extern char version[];
extern int  trace;
} //   "C"

/******************************************************************/
/*  Return a LIBXMLDOC as a XMLDOC.                               */
/******************************************************************/
PXDOC GetLibxmlDoc(PGLOBAL g, char *nsl, char *nsdf, 
                                         char *enc, PFBLOCK fp)
  {
  return (PXDOC) new(g) LIBXMLDOC(nsl, nsdf, enc, fp);
  } // end of GetLibxmlDoc

/******************************************************************/
/*  XML library initialization function.                          */
/******************************************************************/
void XmlInitParserLib(void)
  {
  xmlInitParser();
  } // end of XmlInitParserLib

/******************************************************************/
/*  XML library cleanup function.                                 */
/******************************************************************/
void XmlCleanupParserLib(void)
  {
  xmlCleanupParser();
  xmlMemoryDump();
  } // end of XmlCleanupParserLib

/******************************************************************/
/*  Close a loaded libxml2 XML file.                              */
/******************************************************************/
void CloseXML2File(PGLOBAL g, PFBLOCK fp, bool all)
  {
  PX2BLOCK xp = (PX2BLOCK)fp;

  if (xp && xp->Count > 1 && !all) {
    xp->Count--;
  } else if (xp && xp->Count > 0) {
    xmlFreeDoc(xp->Docp);
    xp->Count = 0;
  } // endif

  } // end of CloseXML2File

/* ---------------------- class LIBXMLDOC ----------------------- */

/******************************************************************/
/*  LIBXMLDOC constructor.                                        */
/******************************************************************/
LIBXMLDOC::LIBXMLDOC(char *nsl, char *nsdf, char *enc, PFBLOCK fp)
         : XMLDOCUMENT(nsl, nsdf, enc)
  {
  assert (!fp || fp->Type == TYPE_FB_XML2);
  Docp = (fp) ? ((PX2BLOCK)fp)->Docp : NULL;
  Nlist = NULL;
  Ctxp = NULL;
  Xop = NULL;
  } // end of LIBXMLDOC constructor

/******************************************************************/
/*  Initialize XML parser and check library compatibility.        */
/******************************************************************/
bool LIBXMLDOC::Initialize(PGLOBAL g)
  {
  int n = xmlKeepBlanksDefault(1);
  return MakeNSlist(g);
  } // end of Initialize

/******************************************************************/
/* Parse the XML file and construct node tree in memory.          */
/******************************************************************/
bool LIBXMLDOC::ParseFile(char *fn)
  {
  if ((Docp = xmlParseFile(fn))) {
    if (Docp->encoding)
      Encoding = (char*)Docp->encoding;

    return false;
  } else
    return true;

  } // end of ParseFile

/******************************************************************/
/* Create or reuse an Xblock for this document.                   */
/******************************************************************/
PFBLOCK LIBXMLDOC::LinkXblock(PGLOBAL g, MODE m, int rc, char *fn)
  {
  PDBUSER  dup = (PDBUSER)g->Activityp->Aptr;
  PX2BLOCK xp = (PX2BLOCK)PlugSubAlloc(g, NULL, sizeof(X2BLOCK));

  memset(xp, 0, sizeof(X2BLOCK));
  xp->Next = (PX2BLOCK)dup->Openlist;
  dup->Openlist = (PFBLOCK)xp;
  xp->Type = TYPE_FB_XML2;
  xp->Fname = (LPCSTR)PlugSubAlloc(g, NULL, strlen(fn) + 1);
  strcpy((char*)xp->Fname, fn);
  xp->Count = 1;
  xp->Length = (m == MODE_READ) ? 1 : 0;
  xp->Retcode = rc;
  xp->Docp = Docp;
//  xp->Ctxp = Ctxp;
//  xp->Xop = Xop;

  // Return xp as a fp
  return (PFBLOCK)xp;
  } // end of LinkXblock

/******************************************************************/
/* Construct and add the XML processing instruction node.         */
/******************************************************************/
bool LIBXMLDOC::NewDoc(PGLOBAL g, char *ver)
  {
  return ((Docp = xmlNewDoc(BAD_CAST ver)) == NULL);
  } // end of NewDoc

/******************************************************************/
/*  Add a new comment node to the document.                       */
/******************************************************************/
void LIBXMLDOC::AddComment(PGLOBAL g, char *txtp)
  {
  xmlNodePtr cp = xmlNewDocComment(Docp, BAD_CAST txtp);
  xmlAddChild((xmlNodePtr)Docp, cp);
  } // end of AddText

/******************************************************************/
/* Return the node class of the root of the document.             */
/******************************************************************/
PXNODE LIBXMLDOC::GetRoot(PGLOBAL g)
  {
  xmlNodePtr root = xmlDocGetRootElement(Docp);

  if (!root)
    return NULL;

  return new(g) XML2NODE(this, root);
  } // end of GetRoot

/******************************************************************/
/* Create a new root element and return its class node.           */
/******************************************************************/
PXNODE LIBXMLDOC::NewRoot(PGLOBAL g, char *name)
  {
  xmlNodePtr root = xmlNewDocNode(Docp, NULL, BAD_CAST name, NULL);

  if (root) {
    xmlDocSetRootElement(Docp, root);
    return new(g) XML2NODE(this, root);
  } else
    return NULL;

  } // end of NewRoot

/******************************************************************/
/* Return a void XML2NODE node class.                             */
/******************************************************************/
PXNODE LIBXMLDOC::NewPnode(PGLOBAL g, char *name)
  {
  xmlNodePtr nop;

  if (name) {
    nop = xmlNewDocNode(Docp, NULL, BAD_CAST name, NULL);

    if (nop == NULL)
      return NULL;

  } else
    nop = NULL;

  return new(g) XML2NODE(this, nop);
  } // end of NewPnode

/******************************************************************/
/* Return a void XML2ATTR node class.                             */
/******************************************************************/
PXATTR LIBXMLDOC::NewPattr(PGLOBAL g)
  {
  return new(g) XML2ATTR(this, NULL, NULL);
  } // end of NewPattr

/******************************************************************/
/* Return a void XML2ATTR node class.                             */
/******************************************************************/
PXLIST LIBXMLDOC::NewPlist(PGLOBAL g)
  {
  return new(g) XML2NODELIST(this, NULL);
  } // end of NewPlist

/******************************************************************/
/* Dump the node tree to a new XML file.                          */
/******************************************************************/
int LIBXMLDOC::DumpDoc(PGLOBAL g, char *ofn)
  {
  int   rc = 0;
  FILE *of;

  if (!(of= global_fopen(g, MSGID_CANNOT_OPEN, ofn, "w")))
    return -1;

#if 1
  // This function does not crash (
  if (xmlSaveFormatFileEnc((const char *)ofn, Docp, Encoding, 0) < 0) {
    xmlErrorPtr err = xmlGetLastError();

    strcpy(g->Message, (err) ? err->message : "Error saving XML doc"
      );
    rc = -1;
    } // endif Save
//  rc = xmlDocDump(of, Docp);
#else // 0
  // Until this function is fixed, do the job ourself
  xmlNodePtr Rootp;

  // Save the modified document
  fprintf(of, "<?xml version=\"1.0\" encoding=\"%s\"?>\n", Encoding);
  fprintf(of, "<!-- Created by CONNECT %s -->\n", version);

  if (!(Rootp = xmlDocGetRootElement(Docp)))
    return 1;

  Buf = (char*)PlugSubAlloc(g, NULL, 1024);
  rc = iconv_close(Cd2);
  Cd2 = iconv_open(Encoding, "UTF-8");
  rc = CheckDocument(of, Rootp);
#endif // 0

  fclose(of);
  return rc;
  } // end of Dump

/******************************************************************/
/* Free the document, cleanup the XML library, and                */
/* debug memory for regression tests.                             */
/******************************************************************/
void LIBXMLDOC::CloseDoc(PGLOBAL g, PFBLOCK xp)
  {
  if (xp && xp->Count == 1) {
    if (Xop)
      xmlXPathFreeObject(Xop);

    if (Ctxp)
      xmlXPathFreeContext(Ctxp);

    } // endif Count

  CloseXML2File(g, xp, false);
  } // end of Close

/******************************************************************/
/* Evaluate the passed Xpath from the passed context node.        */
/******************************************************************/
xmlNodeSetPtr LIBXMLDOC::GetNodeList(PGLOBAL g, xmlNodePtr np, char *xp)
  {
  xmlNodeSetPtr nl;

  if (trace)
    htrc("GetNodeList %s np=%p\n", xp, np);

  if (!Ctxp) {
    // Init Xpath
    xmlXPathInit();

    // Create xpath evaluation context
    if (!(Ctxp = xmlXPathNewContext(Docp))) {
      strcpy(g->Message, MSG(XPATH_CNTX_ERR));

      if (trace)
        htrc("Context error: %s\n", g->Message);

      return NULL;
      } // endif xpathCtx

    // Register namespaces from list (if any)
    for (PNS nsp = Namespaces; nsp; nsp = nsp->Next)
      if (xmlXPathRegisterNs(Ctxp, BAD_CAST nsp->Prefix,
                                   BAD_CAST nsp->Uri)) {
        sprintf(g->Message, MSG(REGISTER_ERR), nsp->Prefix, nsp->Uri);

        if (trace)
          htrc("Ns error: %s\n", g->Message);

        return NULL;
        } // endif Registering

  } else
    xmlXPathFreeNodeSetList(Xop);         // To be checked

  // Set the context to the calling node
  Ctxp->node = np;

  // Evaluate table xpath
  if (!(Xop = xmlXPathEval(BAD_CAST xp, Ctxp))) {
    sprintf(g->Message, MSG(XPATH_EVAL_ERR), xp);

    if (trace)
      htrc("Path error: %s\n", g->Message);

    return NULL;
  } else
    nl = Xop->nodesetval;

  if (trace)
    htrc("GetNodeList nl=%p n=%p\n", nl, (nl) ? nl->nodeNr : 0);

  return nl;
  } // end of GetNodeList

#if 0                                // Not used anymore
/******************************************************************/
/*  CheckDocument: check if the document is ok to dump.           */
/*  Currently this does the dumping of the document.              */
/******************************************************************/
bool LIBXMLDOC::CheckDocument(FILE *of, xmlNodePtr np)
  {
  int  n;
  bool b;

  if (!np)
    return true;

  if (np->type == XML_ELEMENT_NODE) {
    n = fprintf(of, "<%s", np->name);
    b = CheckDocument(of, (xmlNodePtr)np->properties);

    if (np->children)
      n = fprintf(of, ">");
    else
      n = fprintf(of, "/>");

  } else if (np->type == XML_ATTRIBUTE_NODE)
    n = fprintf(of, " %s=\"", np->name);
  else if (np->type == XML_TEXT_NODE)
    n = fprintf(of, "%s", Encode(NULL, (char*)np->content));
  else if (np->type == XML_COMMENT_NODE)
    n = fprintf(of, "%s", Encode(NULL, (char*)np->content));

  b = CheckDocument(of, np->children);

  if (np->type == XML_ATTRIBUTE_NODE)
    n = fprintf(of, "\"");
  else if (!b && np->type == XML_ELEMENT_NODE)
    n = fprintf(of, "</%s>", np->name);

  b = CheckDocument(of, np->next);
  return false;
  } // end of CheckDocument

/******************************************************************/
/*  Convert node or attribute content to latin characters.        */
/******************************************************************/
int LIBXMLDOC::Decode(xmlChar *cnt, char *buf, int n)
  {
  const char *txt = (const char *)cnt;
  uint   dummy_errors;
  uint32 len= copy_and_convert(buf, n, &my_charset_utf8_general_ci, txt,
                               strlen(txt), &my_charset_utf8_general_ci,
                               &dummy_errors);
  buf[len]= '\0';
  return 0;
  } // end of Decode

/******************************************************************/
/*  Convert node or attribute content to latin characters.        */
/******************************************************************/
xmlChar *LIBXMLDOC::Encode(PGLOBAL g, char *txt)
  {
  const CHARSET_INFO *ics= &my_charset_utf8_general_ci;
  const CHARSET_INFO *ocs= &my_charset_utf8_general_ci;
  size_t      i = strlen(txt);
  size_t      o = i * ocs->mbmaxlen / ics->mbmaxlen + 1;
  char        *buf;
  if (g) {
    buf = (char*)PlugSubAlloc(g, NULL, o);
  } else {
    o = 1024;
    buf = Buf;
  } // endif g
  uint dummy_errors;
  uint32 len= copy_and_convert(buf, o, ocs,
                               txt, i, ics,
                               &dummy_errors);
  buf[len]= '\0';
  return BAD_CAST buf;
  } // end of Encode
#endif // 0

/* ---------------------- class XML2NODE ------------------------ */

/******************************************************************/
/*  XML2NODE constructor.                                         */
/******************************************************************/
XML2NODE::XML2NODE(PXDOC dp, xmlNodePtr np) : XMLNODE(dp)
  {
  Docp = ((PXDOC2)dp)->Docp;
  Content = NULL;
  Nodep = np;
  } // end of XML2NODE constructor

int XML2NODE::GetType(void)
  {
  if (trace)
    htrc("GetType type=%d\n", Nodep->type);

  return Nodep->type;
  }  // end of GetType

/******************************************************************/
/*  Return the node class of next sibling of the node.            */
/******************************************************************/
PXNODE XML2NODE::GetNext(PGLOBAL g)
  {
  if (!Nodep->next)
    Next = NULL;
  else if (!Next)
    Next = new(g) XML2NODE(Doc, Nodep->next);

  return Next;
  } // end of GetNext

/******************************************************************/
/*  Return the node class of first children of the node.          */
/******************************************************************/
PXNODE XML2NODE::GetChild(PGLOBAL g)
  {
  if (!Nodep->children)
    Children = NULL;
  else if (!Children)
    Children = new(g) XML2NODE(Doc, Nodep->children);

  return Children;
  } // end of GetChild

/******************************************************************/
/*  Return the content of a node and subnodes.                    */
/******************************************************************/
char *XML2NODE::GetText(char *buf, int len)
  {
  if (Content)
    xmlFree(Content);

  if ((Content = xmlNodeGetContent(Nodep))) {
    char *extra = " \t\r\n";
    char *p1 = (char*)Content, *p2 = buf;
    bool  b = false;

    // Copy content eliminating extra characters
    for (; *p1 && (p2 - buf) < len; p1++)
      if (strchr(extra, *p1)) {
        if (b) {
          // This to have one blank between sub-nodes
          *p2++ = ' ';
          b = false;
          }  // endif b

      } else {
        *p2++ = *p1;
        b = true;
      } // endif p1

    *p2 = 0;

    if (trace)
      htrc("GetText buf='%s' len=%d\n", buf, len);

    xmlFree(Content);
    Content = NULL;
  } else
    *buf = '\0';

  return buf;
  } // end of GetText

/******************************************************************/
/*  Set the content of a node.                                    */
/******************************************************************/
bool XML2NODE::SetContent(PGLOBAL g, char *txtp, int len)
  {
  xmlChar *buf = xmlEncodeEntitiesReentrant(Docp, BAD_CAST txtp);

  if (trace)
    htrc("SetContent %s -> %s\n", txtp, buf);

  xmlNodeSetContent(Nodep, buf);
  xmlFree(buf);
  return false;
  } // end of SetContent

/******************************************************************/
/*  Return a clone of this node.                                  */
/******************************************************************/
PXNODE XML2NODE::Clone(PGLOBAL g, PXNODE np)
  {
  if (np) {
    ((PNODE2)np)->Nodep = Nodep;
    return np;
  } else
    return new(g) XML2NODE(Doc, Nodep);

  } // end of Clone

/******************************************************************/
/*  Return the list of all or matching children that are elements.*/
/******************************************************************/
PXLIST XML2NODE::GetChildElements(PGLOBAL g, char *xp, PXLIST lp)
  {
  if (trace)
    htrc("GetChildElements %s\n", xp);

  return SelectNodes(g, (xp) ? xp : (char*)"*", lp);
  } // end of GetChildElements

/******************************************************************/
/*  Return the list of nodes verifying the passed Xpath.          */
/******************************************************************/
PXLIST XML2NODE::SelectNodes(PGLOBAL g, char *xp, PXLIST lp)
  {
  if (trace)
    htrc("SelectNodes %s\n", xp);

  xmlNodeSetPtr nl = ((PXDOC2)Doc)->GetNodeList(g, Nodep, xp);

  if (lp) {
    ((PLIST2)lp)->Listp = nl;
    return lp;
  } else
    return new(g) XML2NODELIST(Doc, nl);

  } // end of SelectNodes

/******************************************************************/
/*  Return the first node verifying the passed Xapth.             */
/******************************************************************/
PXNODE XML2NODE::SelectSingleNode(PGLOBAL g, char *xp, PXNODE np)
  {
  if (trace)
    htrc("SelectSingleNode %s\n", xp);

  xmlNodeSetPtr nl = ((PXDOC2)Doc)->GetNodeList(g, Nodep, xp);

  if (nl && nl->nodeNr) {
    if (np) {
      ((PNODE2)np)->Nodep = nl->nodeTab[0];
      return np;
    } else
      return new(g) XML2NODE(Doc, nl->nodeTab[0]);

  } else
    return NULL;

  } // end of SelectSingleNode

/******************************************************************/
/*  Return the node attribute with the specified name.            */
/******************************************************************/
PXATTR XML2NODE::GetAttribute(PGLOBAL g, char *name, PXATTR ap)
  {
  if (trace)
    htrc("GetAttribute %s\n", name);

  xmlAttrPtr atp = xmlHasProp(Nodep, BAD_CAST name);

  if (atp) {
    if (ap) {
      ((PATTR2)ap)->Atrp = atp;
      ((PATTR2)ap)->Parent = Nodep;
      return ap;
    } else
      return new(g) XML2ATTR(Doc, atp, Nodep);

  } else
    return NULL;

  } // end of GetAttribute

/******************************************************************/
/*  Add a new child node to this node and return it.              */
/******************************************************************/
PXNODE XML2NODE::AddChildNode(PGLOBAL g, char *name, PXNODE np)
  {
  char *p, *pn, *pf = NULL;

  if (trace)
    htrc("AddChildNode %s\n", name);

  // Is a prefix specified
  if ((pn = strchr(name, ':'))) {
    pf = name;
    *pn++ = '\0';                    // Separate name from prefix
  } else
    pn = name;

  // If name has the format m[n] only m is taken as node name
  if ((p = strchr(pn, '[')))
    p = BufAlloc(g, pn, p - pn);
  else
    p = pn;

  xmlNodePtr nop = xmlNewChild(Nodep, NULL, BAD_CAST p, NULL);

  if (!nop)
    return NULL;

  if (pf) {
    // Prefixed name, is it the default NS prefix?
    if (Doc->DefNs && !strcmp(pf, Doc->DefNs))
      pf = NULL;                        // Default namespace

    xmlNsPtr nsp = xmlSearchNs(Docp, nop, BAD_CAST pf);

    if (!nsp)
      nsp = xmlNewNs(nop, NULL, BAD_CAST pf);

    // Set node namespace
    nop->ns = nsp;
    *(--p) = ':';                       // Restore Xname
  } else if (Doc->DefNs && xmlSearchNs(Docp, nop, NULL))
    // Not in default namespace
    nop->ns = xmlNewNs(nop, BAD_CAST "", NULL);

  if (np)
    ((PNODE2)np)->Nodep = nop;
  else
    np = new(g) XML2NODE(Doc, nop);

  return NewChild(np);
  } // end of AddChildNode

/******************************************************************/
/*  Add a new property to this node and return it.                */
/******************************************************************/
PXATTR XML2NODE::AddProperty(PGLOBAL g, char *name, PXATTR ap)
  {
  if (trace)
    htrc("AddProperty %s\n", name);

  xmlAttrPtr atp = xmlNewProp(Nodep, BAD_CAST name, NULL);

  if (atp) {
    if (ap) {
      ((PATTR2)ap)->Atrp = atp;
      ((PATTR2)ap)->Parent = Nodep;
      return ap;
    } else
      return new(g) XML2ATTR(Doc, atp, Nodep);

  } else
    return NULL;

  } // end of AddProperty

/******************************************************************/
/*  Add a new text node to this node.                             */
/******************************************************************/
void XML2NODE::AddText(PGLOBAL g, char *txtp)
  {
  if (trace)
    htrc("AddText %s\n", txtp);

  // This is to avoid a blank line when inserting a new line
  xmlNodePtr np = xmlGetLastChild(Nodep);

  if (np && np->type == XML_TEXT_NODE) {
    xmlUnlinkNode(np);
    xmlFreeNode(np);
    } // endif type

  // Add the new text
  xmlAddChild(Nodep, xmlNewText(BAD_CAST txtp));
  } // end of AddText

/******************************************************************/
/*  Remove a child node from this node.                           */
/******************************************************************/
void XML2NODE::DeleteChild(PGLOBAL g, PXNODE dnp)
  {
  xmlNodePtr np = ((PNODE2)dnp)->Nodep;
  xmlNodePtr text = np->next;

  // This is specific to row nodes
  if (text && text->type == XML_TEXT_NODE) {
    xmlUnlinkNode(text);
    xmlFreeNode(text);
    } // endif type

  xmlUnlinkNode(np);
  xmlFreeNode(np);
  Delete(dnp);
  } // end of DeleteChild

/* -------------------- class XML2NODELIST ---------------------- */

/******************************************************************/
/*  XML2NODELIST constructor.                                     */
/******************************************************************/
XML2NODELIST::XML2NODELIST(PXDOC dp, xmlNodeSetPtr lp)
            : XMLNODELIST(dp)
  {
  Listp = lp;
  } // end of XML2NODELIST constructor

/******************************************************************/
/*  Return the length of the list.                                */
/******************************************************************/
int XML2NODELIST::GetLength(void)
  {
  return (Listp) ? Listp->nodeNr : 0;
  } // end of GetLength

/******************************************************************/
/*  Return the nth element of the list.                           */
/******************************************************************/
PXNODE XML2NODELIST::GetItem(PGLOBAL g, int n, PXNODE np)
  {
  if (trace)
    htrc("GetItem %d\n", n);

  if (!Listp || Listp->nodeNr <= n)
    return NULL;

  if (np) {
    ((PNODE2)np)->Nodep = Listp->nodeTab[n];
    return np;
  } else
    return new(g) XML2NODE(Doc, Listp->nodeTab[n]);

  } // end of GetItem

/* ---------------------- class XML2ATTR ------------------------ */

/******************************************************************/
/*  XML2ATTR constructor.                                         */
/******************************************************************/
XML2ATTR::XML2ATTR(PXDOC dp, xmlAttrPtr ap, xmlNodePtr np)
        : XMLATTRIBUTE(dp)
  {
  Atrp = ap;
  Parent = np;
  } // end of XML2ATTR constructor

/******************************************************************/
/*  Set the content of an attribute.                              */
/******************************************************************/
bool XML2ATTR::SetText(PGLOBAL g, char *txtp, int len)
  {
  if (trace)
    htrc("SetText %s %d\n", txtp, len);

  xmlSetProp(Parent, Atrp->name, BAD_CAST txtp);
  return false;
  } // end of SetText