/* Copyright (c) 2003, 2011, Oracle and/or its affiliates.
   Copyright (c) 2011 Monty Program Ab

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1335  USA */

#include "strings_def.h"
#include "m_string.h"
#include "my_xml.h"
#include "my_sys.h"


#define MY_XML_UNKNOWN  'U'
#define MY_XML_EOF	'E'
#define MY_XML_STRING	'S'
#define MY_XML_IDENT	'I'
#define MY_XML_EQ	'='
#define MY_XML_LT	'<'
#define MY_XML_GT	'>'
#define MY_XML_SLASH	'/'
#define MY_XML_COMMENT	'C'
#define MY_XML_TEXT	'T'
#define MY_XML_QUESTION	'?'
#define MY_XML_EXCLAM   '!'
#define MY_XML_CDATA    'D'

typedef struct xml_attr_st
{
  const char *beg;
  const char *end;
} MY_XML_ATTR;


/*
  XML ctype:
*/
#define	MY_XML_ID0  0x01 /* Identifier initial character */
#define	MY_XML_ID1  0x02 /* Identifier medial  character */
#define	MY_XML_SPC  0x08 /* Spacing character */


/*
 http://www.w3.org/TR/REC-xml/ 
 [4] NameChar ::= Letter | Digit | '.' | '-' | '_' | ':' |
                  CombiningChar | Extender
 [5] Name ::= (Letter | '_' | ':') (NameChar)*
*/

static char my_xml_ctype[256]=
{
/*00*/  0,0,0,0,0,0,0,0,0,8,8,0,0,8,0,0,
/*10*/  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
/*20*/  8,0,0,0,0,0,0,0,0,0,0,0,0,2,2,0,  /*  !"#$%&'()*+,-./ */
/*30*/  2,2,2,2,2,2,2,2,2,2,3,0,0,0,0,0,  /* 0123456789:;<=>? */
/*40*/  0,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,  /* @ABCDEFGHIJKLMNO */
/*50*/  3,3,3,3,3,3,3,3,3,3,3,0,0,0,0,3,  /* PQRSTUVWXYZ[\]^_ */
/*60*/  0,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,  /* `abcdefghijklmno */
/*70*/  3,3,3,3,3,3,3,3,3,3,3,0,0,0,0,0,  /* pqrstuvwxyz{|}~  */
/*80*/  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
/*90*/  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
/*A0*/  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
/*B0*/  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
/*C0*/  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
/*D0*/  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
/*E0*/  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
/*F0*/  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3
};

#define my_xml_is_space(c)  (my_xml_ctype[(uchar) (c)] & MY_XML_SPC)
#define my_xml_is_id0(c)    (my_xml_ctype[(uchar) (c)] & MY_XML_ID0)
#define my_xml_is_id1(c)    (my_xml_ctype[(uchar) (c)] & MY_XML_ID1)


static const char *lex2str(int lex)
{
  switch(lex)
  {
    case MY_XML_EOF:      return "END-OF-INPUT";
    case MY_XML_STRING:   return "STRING";
    case MY_XML_IDENT:    return "IDENT";
    case MY_XML_CDATA:    return "CDATA";
    case MY_XML_EQ:       return "'='";
    case MY_XML_LT:       return "'<'";
    case MY_XML_GT:       return "'>'";
    case MY_XML_SLASH:    return "'/'";
    case MY_XML_COMMENT:  return "COMMENT";
    case MY_XML_TEXT:     return "TEXT";
    case MY_XML_QUESTION: return "'?'";
    case MY_XML_EXCLAM:   return "'!'";
  }
  return "unknown token";
}

static void my_xml_norm_text(MY_XML_ATTR *a)
{
  for ( ; (a->beg < a->end) && my_xml_is_space(a->beg[0]) ; a->beg++ );
  for ( ; (a->beg < a->end) && my_xml_is_space(a->end[-1]) ; a->end-- );
}


static inline my_bool
my_xml_parser_prefix_cmp(MY_XML_PARSER *p, const char *s, size_t slen)
{
  return (p->cur + slen > p->end) || memcmp(p->cur, s, slen);
}


static int my_xml_scan(MY_XML_PARSER *p,MY_XML_ATTR *a)
{
  int lex;
  
  for (; ( p->cur < p->end) && my_xml_is_space(p->cur[0]) ;  p->cur++);
  
  if (p->cur >= p->end)
  {
    a->beg=p->end;
    a->end=p->end;
    lex=MY_XML_EOF;
    goto ret;
  }
  
  a->beg=p->cur;
  a->end=p->cur;
  
  if (!my_xml_parser_prefix_cmp(p, C_STRING_WITH_LEN("<!--")))
  {
    for (; p->cur < p->end; p->cur++)
    {
      if (!my_xml_parser_prefix_cmp(p, C_STRING_WITH_LEN("-->")))
      {
        p->cur+= 3;
        break;
      }
    }
    a->end=p->cur;
    lex=MY_XML_COMMENT;
  }
  else if (!my_xml_parser_prefix_cmp(p, C_STRING_WITH_LEN("<![CDATA[")))
  {
    p->cur+= 9;
    for (; p->cur < p->end - 2 ; p->cur++)
    {
      if (p->cur[0] == ']' && p->cur[1] == ']' && p->cur[2] == '>')
      {
        p->cur+= 3;
        a->end= p->cur;
        break;
      }
    }
    lex= MY_XML_CDATA;
  }
  else if (strchr("?=/<>!",p->cur[0]))
  {
    p->cur++;
    a->end=p->cur;
    lex=a->beg[0];
  }
  else if ( (p->cur[0] == '"') || (p->cur[0] == '\'') )
  {
    /*
      "string" or 'string' found.
      Scan until the closing quote/doublequote, or until the END-OF-INPUT.
    */
    p->cur++;
    for (; ( p->cur < p->end ) && (p->cur[0] != a->beg[0]); p->cur++)
    {}
    a->end=p->cur;
    if (p->cur < p->end) /* Closing quote or doublequote has been found */
      p->cur++;
    a->beg++;
    if (!(p->flags & MY_XML_FLAG_SKIP_TEXT_NORMALIZATION))
      my_xml_norm_text(a);
    lex=MY_XML_STRING;
  }
  else if (my_xml_is_id0(p->cur[0]))
  {
    p->cur++;
    while (p->cur < p->end && my_xml_is_id1(p->cur[0]))
      p->cur++;
    a->end=p->cur;
    my_xml_norm_text(a);
    lex=MY_XML_IDENT;
  }
  else
    lex= MY_XML_UNKNOWN;

#if 0
  printf("LEX=%s[%d]\n",lex2str(lex),a->end-a->beg);
#endif

ret:
  return lex;
}


static int my_xml_value(MY_XML_PARSER *st, const char *str, size_t len)
{
  return (st->value) ? (st->value)(st,str,len) : MY_XML_OK;
}


/**
  Ensure the attr buffer is wide enough to hold the new value

  Expand and/or allocate dynamic buffer as needed to hold the concatenated
  path and the terminating zero.

  @attr st   the parser instance
  @attr len  the length of the attribute to be added
  @return state
  @retval 1  failed
  @retval 0  success
*/
static int my_xml_attr_ensure_space(MY_XML_PARSER *st, size_t len)
{
  size_t ofs= st->attr.end - st->attr.start;
  len++; // Add terminating zero.
  if (ofs + len > st->attr.buffer_size)
  {
    st->attr.buffer_size= (SIZE_T_MAX - len) / 2 > st->attr.buffer_size ?
                            st->attr.buffer_size * 2 + len : SIZE_T_MAX;

    if (!st->attr.buffer)
    {
      st->attr.buffer= (char *) my_malloc(PSI_INSTRUMENT_ME, st->attr.buffer_size, MYF(0));
      if (st->attr.buffer)
        memcpy(st->attr.buffer, st->attr.static_buffer, ofs + 1 /*term. zero */);
    }
    else
      st->attr.buffer= (char *) my_realloc(PSI_INSTRUMENT_ME, st->attr.buffer,
                                           st->attr.buffer_size, MYF(0));
    st->attr.start= st->attr.buffer;
    st->attr.end= st->attr.start + ofs;
    
    return st->attr.buffer ? MY_XML_OK : MY_XML_ERROR;
  }
  return MY_XML_OK;
}


/** rewind the attr buffer to initial state */
static void my_xml_attr_rewind(MY_XML_PARSER *p)
{
  /* keep the buffer already allocated */
  p->attr.end= p->attr.start;
}


static int my_xml_enter(MY_XML_PARSER *st, const char *str, size_t len)
{
  if (my_xml_attr_ensure_space(st, len + 1 /* the separator char */))
    return MY_XML_ERROR;

  if (st->attr.end > st->attr.start)
  {
    st->attr.end[0]= '/';
    st->attr.end++;
  }
  memcpy(st->attr.end, str, len);
  st->attr.end+= len;
  st->attr.end[0]= '\0';
  if (st->flags & MY_XML_FLAG_RELATIVE_NAMES)
    return st->enter ? st->enter(st, str, len) : MY_XML_OK;
  else
    return st->enter ?
      st->enter(st, st->attr.start, st->attr.end - st->attr.start) : MY_XML_OK;
}


static void mstr(char *s,const char *src,size_t l1, size_t l2)
{
  l1 = l1<l2 ? l1 : l2;
  memcpy(s,src,l1);
  s[l1]='\0';
}


static int my_xml_leave(MY_XML_PARSER *p, const char *str, size_t slen)
{
  char *e, *tag;
  size_t glen;
  char s[32];
  char g[32];
  int  rc;

  /* Find previous '/' or beginning */
  for (e= p->attr.end; (e > p->attr.start) && (e[0] != '/') ; e--);
  glen= (size_t) ((e[0] == '/') ? (p->attr.end - e - 1) : p->attr.end - e);
  tag= e[0] == '/' ? e + 1 : e;
  
  if (str && (slen != glen || memcmp(str, tag, slen)))
  {
    mstr(s,str,sizeof(s)-1,slen);
    if (glen)
    {
      mstr(g, tag, sizeof(g)-1, glen);
      snprintf(p->errstr,sizeof(p->errstr),"'</%s>' unexpected ('</%s>' wanted)",s,g);
    }
    else
      snprintf(p->errstr,sizeof(p->errstr),"'</%s>' unexpected (END-OF-INPUT wanted)", s);
    return MY_XML_ERROR;
  }
  
  if (p->flags & MY_XML_FLAG_RELATIVE_NAMES)
    rc= p->leave_xml ? p->leave_xml(p, str, slen) : MY_XML_OK;
  else
    rc= (p->leave_xml ? 
         p->leave_xml(p, p->attr.start, p->attr.end - p->attr.start) :
         MY_XML_OK);
  
  *e='\0';
  p->attr.end= e;
  
  return rc;
}


int my_xml_parse(MY_XML_PARSER *p,const char *str, size_t len)
{

  my_xml_attr_rewind(p);

  p->beg=str;
  p->cur=str;
  p->end=str+len;
  
  while ( p->cur < p->end )
  {
    MY_XML_ATTR a;
    if (p->cur[0] == '<')
    {
      int lex;
      int question=0;
      int exclam=0;
      
      lex=my_xml_scan(p,&a);
      
      if (MY_XML_COMMENT == lex)
        continue;
      
      if (lex == MY_XML_CDATA)
      {
        a.beg+= 9;
        a.end-= 3;
        my_xml_value(p, a.beg, (size_t) (a.end-a.beg));
        continue;
      }
      
      lex=my_xml_scan(p,&a);
      
      if (MY_XML_SLASH == lex)
      {
        if (MY_XML_IDENT != (lex=my_xml_scan(p,&a)))
        {
          snprintf(p->errstr,sizeof(p->errstr),"%s unexpected (ident wanted)",lex2str(lex));
          return MY_XML_ERROR;
        }
        if (MY_XML_OK != my_xml_leave(p,a.beg,(size_t) (a.end-a.beg)))
          return MY_XML_ERROR;
        lex=my_xml_scan(p,&a);
        goto gt;
      }
      
      if (MY_XML_EXCLAM == lex)
      {
        lex=my_xml_scan(p,&a);
        exclam=1;
      }
      else if (MY_XML_QUESTION == lex)
      {
        lex=my_xml_scan(p,&a);
        question=1;
      }
      
      if (MY_XML_IDENT == lex)
      {
        p->current_node_type= MY_XML_NODE_TAG;
        if (MY_XML_OK != my_xml_enter(p,a.beg,(size_t) (a.end-a.beg)))
          return MY_XML_ERROR;
      }
      else
      {
        snprintf(p->errstr,sizeof(p->errstr),"%s unexpected (ident or '/' wanted)",
		lex2str(lex));
        return MY_XML_ERROR;
      }
      
      while ((MY_XML_IDENT == (lex=my_xml_scan(p,&a))) ||
             ((MY_XML_STRING == lex && exclam)))
      {
        MY_XML_ATTR b;
        if (MY_XML_EQ == (lex=my_xml_scan(p,&b)))
        {
          lex=my_xml_scan(p,&b);
          if ( (lex == MY_XML_IDENT) || (lex == MY_XML_STRING) )
          {
            p->current_node_type= MY_XML_NODE_ATTR;
            if ((MY_XML_OK != my_xml_enter(p,a.beg,(size_t) (a.end-a.beg)))  ||
                (MY_XML_OK != my_xml_value(p,b.beg,(size_t) (b.end-b.beg)))  ||
                (MY_XML_OK != my_xml_leave(p,a.beg,(size_t) (a.end-a.beg))))
              return MY_XML_ERROR;
          }
          else
          {
            snprintf(p->errstr,sizeof(p->errstr),"%s unexpected (ident or string wanted)",
		    lex2str(lex));
            return MY_XML_ERROR;
          }
        }
        else if (MY_XML_IDENT == lex)
        {
          p->current_node_type= MY_XML_NODE_ATTR;
          if ((MY_XML_OK != my_xml_enter(p,a.beg,(size_t) (a.end-a.beg))) ||
              (MY_XML_OK != my_xml_leave(p,a.beg,(size_t) (a.end-a.beg))))
           return MY_XML_ERROR;
        }
        else if ((MY_XML_STRING == lex) && exclam)
        {
          /*
            We are in <!DOCTYPE>, e.g.
            <!DOCTYPE name SYSTEM "SystemLiteral">
            <!DOCTYPE name PUBLIC "PublidLiteral" "SystemLiteral">
            Just skip "SystemLiteral" and "PublicidLiteral"
          */
        }
        else
          break;
      }
      
      if (lex == MY_XML_SLASH)
      {
        if (MY_XML_OK != my_xml_leave(p,NULL,0))
          return MY_XML_ERROR;
        lex=my_xml_scan(p,&a);
      }
      
gt:
      if (question)
      {
        if (lex != MY_XML_QUESTION)
        {
          snprintf(p->errstr,sizeof(p->errstr),"%s unexpected ('?' wanted)",lex2str(lex));
          return MY_XML_ERROR;
        }
        if (MY_XML_OK != my_xml_leave(p,NULL,0))
          return MY_XML_ERROR;
        lex=my_xml_scan(p,&a);
      }
      
      if (exclam)
      {
        if (MY_XML_OK != my_xml_leave(p,NULL,0))
          return MY_XML_ERROR;
      }
      
      if (lex != MY_XML_GT)
      {
        snprintf(p->errstr,sizeof(p->errstr),"%s unexpected ('>' wanted)",lex2str(lex));
        return MY_XML_ERROR;
      }
    }
    else
    {
      a.beg=p->cur;
      for ( ; (p->cur < p->end) && (p->cur[0] != '<')  ; p->cur++);
      a.end=p->cur;
      
      if (!(p->flags & MY_XML_FLAG_SKIP_TEXT_NORMALIZATION))
        my_xml_norm_text(&a);
      if (a.beg != a.end)
      {
        my_xml_value(p,a.beg,(size_t) (a.end-a.beg));
      }
    }
  }

  if (p->attr.start[0])
  {
    snprintf(p->errstr,sizeof(p->errstr),"unexpected END-OF-INPUT");
    return MY_XML_ERROR;
  }
  return MY_XML_OK;
}


void my_xml_parser_create(MY_XML_PARSER *p)
{
  memset(p, 0, sizeof(p[0]));
  /*
    Use static buffer while it's sufficient.
  */
  p->attr.start= p->attr.end= p->attr.static_buffer;
  p->attr.buffer_size= sizeof(p->attr.static_buffer);
}


void my_xml_parser_free(MY_XML_PARSER *p)
{
  if (p->attr.buffer)
  {
    my_free(p->attr.buffer);
    p->attr.buffer= NULL;
  }
}


void my_xml_set_value_handler(MY_XML_PARSER *p,
			      int (*action)(MY_XML_PARSER *p, const char *s,
					    size_t l))
{
  p->value=action;
}

void my_xml_set_enter_handler(MY_XML_PARSER *p,
			      int (*action)(MY_XML_PARSER *p, const char *s,
					    size_t l))
{
  p->enter=action;
}


void my_xml_set_leave_handler(MY_XML_PARSER *p,
			      int (*action)(MY_XML_PARSER *p, const char *s,
					    size_t l))
{
  p->leave_xml=action;
}


void my_xml_set_user_data(MY_XML_PARSER *p, void *user_data)
{
  p->user_data=user_data;
}


const char *my_xml_error_string(MY_XML_PARSER *p)
{
  return p->errstr;
}


size_t my_xml_error_pos(MY_XML_PARSER *p)
{
  const char *beg=p->beg;
  const char *s;
  for ( s=p->beg ; s<p->cur; s++)
  {
    if (s[0] == '\n')
      beg=s;
  }
  return (size_t) (p->cur-beg);
}

uint my_xml_error_lineno(MY_XML_PARSER *p)
{
  uint res=0;
  const char *s;
  for (s=p->beg ; s<p->cur; s++)
  {
    if (s[0] == '\n')
      res++;
  }
  return res;
}
