text: #include "http_conn.h"
  
  const char* ok_200_title = "OK";
  const char* error_400_title = "Bad Request";
  const char* error_400_form = "Your request has bad syntax or is inherently impossible to satisfy.\n";
  const char* error_403_title = "Forbidden";
  const char* error_403_form = "You do not have permission to get file from this server.\n";
  const char* error_404_title = "Not Found";
  const char* error_404_form = "The requested file was not found on this server.\n";
  const char* error_500_title = "Internal Error";
  const char* error_500_form = "There was an unusual problem serving the requested file.\n";
  const char* doc_root = "/var/www/html";
  
  int setnonblocking( int fd )
  {
      int old_option = fcntl( fd, F_GETFL );
      int new_option = old_option | O_NONBLOCK;
      fcntl( fd, F_SETFL, new_option );
      return old_option;
  }
  
  void addfd( int epollfd, int fd, bool one_shot )
  {
      epoll_event event;
      event.data.fd = fd;
      event.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
      if( one_shot )
      {
          event.events |= EPOLLONESHOT;
      }
      epoll_ctl( epollfd, EPOLL_CTL_ADD, fd, &event );
      setnonblocking( fd );
  }
  
  void removefd( int epollfd, int fd )
  {
      epoll_ctl( epollfd, EPOLL_CTL_DEL, fd, 0 );
      close( fd );
  }
  
  void modfd( int epollfd, int fd, int ev )
  {
      epoll_event event;
      event.data.fd = fd;
      event.events = ev | EPOLLET | EPOLLONESHOT | EPOLLRDHUP;
      epoll_ctl( epollfd, EPOLL_CTL_MOD, fd, &event );
  }
  
  int http_conn::m_user_count = 0;
  int http_conn::m_epollfd = -1;
  
  void http_conn::close_conn( bool real_close )
  {
      if( real_close && ( m_sockfd != -1 ) )
      {
          //modfd( m_epollfd, m_sockfd, EPOLLIN );
          removefd( m_epollfd, m_sockfd );
          m_sockfd = -1;
          m_user_count--;
      }
  }
  
  void http_conn::init( int sockfd, const sockaddr_in& addr )
  {
      m_sockfd = sockfd;
      m_address = addr;
      int error = 0;
      socklen_t len = sizeof( error );
      getsockopt( m_sockfd, SOL_SOCKET, SO_ERROR, &error, &len );
      int reuse = 1;
      setsockopt( m_sockfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof( reuse ) );
      addfd( m_epollfd, sockfd, true );
      m_user_count++;
  
      init();
  }
  
  void http_conn::init()
  {
      m_check_state = CHECK_STATE_REQUESTLINE;
      m_linger = false;
  
      m_method = GET;
      m_url = 0;
      m_version = 0;
      m_content_length = 0;
      m_host = 0;
      m_start_line = 0;
      m_checked_idx = 0;
      m_read_idx = 0;
      m_write_idx = 0;
      memset( m_read_buf, '\0', READ_BUFFER_SIZE );
      memset( m_write_buf, '\0', WRITE_BUFFER_SIZE );
      memset( m_real_file, '\0', FILENAME_LEN );
  }
  
  http_conn::LINE_STATUS http_conn::parse_line()
  {
      char temp;
      for ( ; m_checked_idx < m_read_idx; ++m_checked_idx )
      {
          temp = m_read_buf[ m_checked_idx ];
          if ( temp == '\r' )
          {
              if ( ( m_checked_idx + 1 ) == m_read_idx )
              {
                  return LINE_OPEN;
              }
              else if ( m_read_buf[ m_checked_idx + 1 ] == '\n' )
              {
                  m_read_buf[ m_checked_idx++ ] = '\0';
                  m_read_buf[ m_checked_idx++ ] = '\0';
                  return LINE_OK;
              }
  
              return LINE_BAD;
          }
          else if( temp == '\n' )
          {
              if( ( m_checked_idx > 1 ) && ( m_read_buf[ m_checked_idx - 1 ] == '\r' ) )
              {
                  m_read_buf[ m_checked_idx-1 ] = '\0';
                  m_read_buf[ m_checked_idx++ ] = '\0';
                  return LINE_OK;
              }
              return LINE_BAD;
          }
      }
  
      return LINE_OPEN;
  }
  
  bool http_conn::read()
  {
      if( m_read_idx >= READ_BUFFER_SIZE )
      {
          return false;
      }
  
      int bytes_read = 0;
      while( true )
      {
          bytes_read = recv( m_sockfd, m_read_buf + m_read_idx, READ_BUFFER_SIZE - m_read_idx, 0 );
          if ( bytes_read == -1 )
          {
              if( errno == EAGAIN || errno == EWOULDBLOCK )
              {
                  break;
              }
              return false;
          }
          else if ( bytes_read == 0 )
          {
              return false;
          }
  
          m_read_idx += bytes_read;
      }
      return true;
  }
  
  http_conn::HTTP_CODE http_conn::parse_request_line( char* text )
  {
      m_url = strpbrk( text, " \t" );
      if ( ! m_url )
      {
          return BAD_REQUEST;
      }
      *m_url++ = '\0';
  
      char* method = text;
      if ( strcasecmp( method, "GET" ) == 0 )
      {
          m_method = GET;
      }
      else
      {
          return BAD_REQUEST;
      }
  
      m_url += strspn( m_url, " \t" );
      m_version = strpbrk( m_url, " \t" );
      if ( ! m_version )
      {
          return BAD_REQUEST;
      }
      *m_version++ = '\0';
      m_version += strspn( m_version, " \t" );
      if ( strcasecmp( m_version, "HTTP/1.1" ) != 0 )
      {
          return BAD_REQUEST;
      }
  
      if ( strncasecmp( m_url, "http://", 7 ) == 0 )
      {
          m_url += 7;
          m_url = strchr( m_url, '/' );
      }
  
      if ( ! m_url || m_url[ 0 ] != '/' )
      {
          return BAD_REQUEST;
      }
  
      m_check_state = CHECK_STATE_HEADER;
      return NO_REQUEST;
  }
  
  http_conn::HTTP_CODE http_conn::parse_headers( char* text )
  {
      if( text[ 0 ] == '\0' )
      {
          if ( m_method == HEAD )
          {
              return GET_REQUEST;
          }
  
          if ( m_content_length != 0 )
          {
              m_check_state = CHECK_STATE_CONTENT;
              return NO_REQUEST;
          }
  
          return GET_REQUEST;
      }
      else if ( strncasecmp( text, "Connection:", 11 ) == 0 )
      {
          text += 11;
          text += strspn( text, " \t" );
          if ( strcasecmp( text, "keep-alive" ) == 0 )
          {
              m_linger = true;
          }
      }
      else if ( strncasecmp( text, "Content-Length:", 15 ) == 0 )
      {
          text += 15;
          text += strspn( text, " \t" );
          m_content_length = atol( text );
      }
      else if ( strncasecmp( text, "Host:", 5 ) == 0 )
      {
          text += 5;
          text += strspn( text, " \t" );
          m_host = text;
      }
      else
      {
          printf( "oop! unknow header %s\n", text );
      }
  
      return NO_REQUEST;
  
  }
  
  http_conn::HTTP_CODE http_conn::parse_content( char* text )
  {
      if ( m_read_idx >= ( m_content_length + m_checked_idx ) )
      {
          text[ m_content_length ] = '\0';
          return GET_REQUEST;
      }
  
      return NO_REQUEST;
  }
  
  http_conn::HTTP_CODE http_conn::process_read()
  {
      LINE_STATUS line_status = LINE_OK;
      HTTP_CODE ret = NO_REQUEST;
      char* text = 0;
  
      while ( ( ( m_check_state == CHECK_STATE_CONTENT ) && ( line_status == LINE_OK  ) )
                  || ( ( line_status = parse_line() ) == LINE_OK ) )
      {
          text = get_line();
          m_start_line = m_checked_idx;
          printf( "got 1 http line: %s\n", text );
  
          switch ( m_check_state )
          {
              case CHECK_STATE_REQUESTLINE:
              {
                  ret = parse_request_line( text );
                  if ( ret == BAD_REQUEST )
                  {
                      return BAD_REQUEST;
                  }
                  break;
              }
              case CHECK_STATE_HEADER:
              {
                  ret = parse_headers( text );
                  if ( ret == BAD_REQUEST )
                  {
                      return BAD_REQUEST;
                  }
                  else if ( ret == GET_REQUEST )
                  {
                      return do_request();
                  }
                  break;
              }
              case CHECK_STATE_CONTENT:
              {
                  ret = parse_content( text );
                  if ( ret == GET_REQUEST )
                  {
                      return do_request();
                  }
                  line_status = LINE_OPEN;
                  break;
              }
              default:
              {
                  return INTERNAL_ERROR;
              }
          }
      }
  
      return NO_REQUEST;
  }
  
  http_conn::HTTP_CODE http_conn::do_request()
  {
      strcpy( m_real_file, doc_root );
      int len = strlen( doc_root );
      strncpy( m_real_file + len, m_url, FILENAME_LEN - len - 1 );
      if ( stat( m_real_file, &m_file_stat ) < 0 )
      {
          return NO_RESOURCE;
      }
  
      if ( ! ( m_file_stat.st_mode & S_IROTH ) )
      {
          return FORBIDDEN_REQUEST;
      }
  
      if ( S_ISDIR( m_file_stat.st_mode ) )
      {
          return BAD_REQUEST;
      }
  
      int fd = open( m_real_file, O_RDONLY );
      m_file_address = ( char* )mmap( 0, m_file_stat.st_size, PROT_READ, MAP_PRIVATE, fd, 0 );
      close( fd );
      return FILE_REQUEST;
  }
  
  void http_conn::unmap()
  {
      if( m_file_address )
      {
          munmap( m_file_address, m_file_stat.st_size );
          m_file_address = 0;
      }
  }
  
  bool http_conn::write()
  {
      int temp = 0;
      int bytes_have_send = 0;
      int bytes_to_send = m_write_idx;
      if ( bytes_to_send == 0 )
      {
          modfd( m_epollfd, m_sockfd, EPOLLIN );
          init();
          return true;
      }
  
      while( 1 )
      {
          temp = writev( m_sockfd, m_iv, m_iv_count );
          if ( temp <= -1 )
          {
              if( errno == EAGAIN )
              {
                  modfd( m_epollfd, m_sockfd, EPOLLOUT );
                  return true;
              }
              unmap();
              return false;
          }
  
          bytes_to_send -= temp;
          bytes_have_send += temp;
          if ( bytes_to_send <= bytes_have_send )
          {
              unmap();
              if( m_linger )
              {
                  init();
                  modfd( m_epollfd, m_sockfd, EPOLLIN );
                  return true;
              }
              else
              {
                  modfd( m_epollfd, m_sockfd, EPOLLIN );
                  return false;
              } 
          }
      }
  }
  
  bool http_conn::add_response( const char* format, ... )
  {
      if( m_write_idx >= WRITE_BUFFER_SIZE )
      {
          return false;
      }
      va_list arg_list;
      va_start( arg_list, format );
      int len = vsnprintf( m_write_buf + m_write_idx, WRITE_BUFFER_SIZE - 1 - m_write_idx, format, arg_list );
      if( len >= ( WRITE_BUFFER_SIZE - 1 - m_write_idx ) )
      {
          return false;
      }
      m_write_idx += len;
      va_end( arg_list );
      return true;
  }
  
  bool http_conn::add_status_line( int status, const char* title )
  {
      return add_response( "%s %d %s\r\n", "HTTP/1.1", status, title );
  }
  
  bool http_conn::add_headers( int content_len )
  {
      add_content_length( content_len );
      add_linger();
      add_blank_line();
      return true;
  }
  
  bool http_conn::add_content_length( int content_len )
  {
      return add_response( "Content-Length: %d\r\n", content_len );
  }
  
  bool http_conn::add_linger()
  {
      return add_response( "Connection: %s\r\n", ( m_linger == true ) ? "keep-alive" : "close" );
  }
  
  bool http_conn::add_blank_line()
  {
      return add_response( "%s", "\r\n" );
  }
  
  bool http_conn::add_content( const char* content )
  {
      return add_response( "%s", content );
  }
  
  bool http_conn::process_write( HTTP_CODE ret )
  {
      switch ( ret )
      {
          case INTERNAL_ERROR:
          {
              add_status_line( 500, error_500_title );
              add_headers( strlen( error_500_form ) );
              if ( ! add_content( error_500_form ) )
              {
                  return false;
              }
              break;
          }
          case BAD_REQUEST:
          {
              add_status_line( 400, error_400_title );
              add_headers( strlen( error_400_form ) );
              if ( ! add_content( error_400_form ) )
              {
                  return false;
              }
              break;
          }
          case NO_RESOURCE:
          {
              add_status_line( 404, error_404_title );
              add_headers( strlen( error_404_form ) );
              if ( ! add_content( error_404_form ) )
              {
                  return false;
              }
              break;
          }
          case FORBIDDEN_REQUEST:
          {
              add_status_line( 403, error_403_title );
              add_headers( strlen( error_403_form ) );
              if ( ! add_content( error_403_form ) )
              {
                  return false;
              }
              break;
          }
          case FILE_REQUEST:
          {
              add_status_line( 200, ok_200_title );
              if ( m_file_stat.st_size != 0 )
              {
                  add_headers( m_file_stat.st_size );
                  m_iv[ 0 ].iov_base = m_write_buf;
                  m_iv[ 0 ].iov_len = m_write_idx;
                  m_iv[ 1 ].iov_base = m_file_address;
                  m_iv[ 1 ].iov_len = m_file_stat.st_size;
                  m_iv_count = 2;
                  return true;
              }
              else
              {
                  const char* ok_string = "<html><body></body></html>";
                  add_headers( strlen( ok_string ) );
                  if ( ! add_content( ok_string ) )
                  {
                      return false;
                  }
              }
          }
          default:
          {
              return false;
          }
      }
  
      m_iv[ 0 ].iov_base = m_write_buf;
      m_iv[ 0 ].iov_len = m_write_idx;
      m_iv_count = 1;
      return true;
  }
  
  void http_conn::process()
  {
      HTTP_CODE read_ret = process_read();
      if ( read_ret == NO_REQUEST )
      {
          modfd( m_epollfd, m_sockfd, EPOLLIN );
          return;
      }
  
      bool write_ret = process_write( read_ret );
      if ( ! write_ret )
      {
          close_conn();
      }
  
      modfd( m_epollfd, m_sockfd, EPOLLOUT );
  }
  