** array for each line of text.
**
** **Warning:**  This is an internal-use-only interface that is subject to
** change at any moment.  External application should not use this interface
** since the application will break when this interface changes, and this
** interface will undoubtedly change.
**
** This page is intended to be used in an XHR from javascript on a diff
** page, to return unseen context to fill in additional context when the
** user clicks on the appropriate button.
** This page is intended to be used in an XHR from javascript on a
** diff page, to return unseen context to fill in additional context
** when the user clicks on the appropriate button. The response is
** always in JSON form and errors are reported as documented for
** ajax_route_error().
*/
void jtext_page(void){
  int rid = 0;
  const char *zName = PD("name", "");
  int iFrom = atoi(PD("from","0"));
  int iTo = atoi(PD("to","0"));
  int ln;
  int go = 1;
  const char *zSep;
  Blob content;
  Blob line;
  Blob *pOut;

  login_check_credentials();
  if( !g.perm.Read ){ login_needed(g.anon.Read); return; }
  if( !g.perm.Read ){
    ajax_route_error(403, "Access requires Read permissions.");
    return;
  }
#if 0
  /* Re-enable this block once this code is integrated somewhere into
     the UI. */
  rid = db_int(0, "SELECT rid FROM blob WHERE uuid=%Q", zName);
  if( rid==0 ){
    ajax_route_error(404, "Unknown artifact: %h", zName);
    return;
  }
#else
  /* This impl is only to simplify "manual" testing via the JS
     console. */
  rid = symbolic_name_to_rid(zName, "*");
  if( rid==0 ){
    ajax_route_error(404, "Unknown artifact: %h", zName);
    return;
  }else if( rid<0 ){
    ajax_route_error(404, "Ambiguous artifact name: %h", zName);
    ajax_route_error(418, "Ambiguous artifact name: %h", zName);
    return;
  }
#endif
  if( iFrom<1 || iTo<iFrom ){
    ajax_route_error(500, "Invalid line range from=%d, to=%d.",
                     iFrom, iTo);
    return;