texinfo/js/src/toc.js

/* toc.js - Generate and manage the table of content
   Copyright © 2017 Free Software Foundation, Inc.

   This file is part of GNU Texinfo.

   GNU Texinfo 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, either version 3 of the License, or
   (at your option) any later version.

   GNU Texinfo 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 GNU Texinfo.  If not, see <http://www.gnu.org/licenses/>.  */

import {
  absolute_url_p,
  basename,
  depth_first_walk,
  href_hash
} from "./utils";

import config from "./config";

/** Return a relative URL corresponding to HREF, which refers to an anchor of
    'config.INDEX_NAME'.  URL must be a USVString representing an absolute or
    relative URL.

    For example "foo/bar.html" will return "config.INDEX_NAME#bar".  */
export function
with_sidebar_query (href)
{
  if (basename (href) === config.INDEX_NAME)
    return config.INDEX_NAME;
  else
    {
      let url = new window.URL (href, window.location);
      let new_hash = basename (url.pathname, /[.]x?html/);
      if (url.hash)
        new_hash += ("." + url.hash.slice (1));
      return config.INDEX_NAME + "#" + new_hash;
    }
}

/* Keep children but remove grandchildren (Exception: don't remove
   anything on the current page; however, that's not a problem in the
   Kawa manual).  */
function
hide_grand_child_nodes (ul)
{
  for (let li = ul.firstElementChild; li; li = li.nextElementSibling)
    {
      let a = li.firstElementChild;
      let li$ = a && a.nextElementSibling;
      /* Never remove Overall-Index.  */
      if (li$ && a.getAttribute ("href") !== config.OVERALL_INDEX_NAME)
        li$.setAttribute ("toc-detail", "yes");
    }
}

/** Scan ToC entries to see which should be hidden.  */
export function
scan_toc (node, filename)
{
  var current = with_sidebar_query (filename);
  var ul = node.querySelector ("ul");
  if (filename === config.INDEX_NAME)
    hide_grand_child_nodes (ul);
  else
    scan_toc1 (ul, current);
}

/* Scan ToC entries to see which should be hidden.  Return "current" if node
   matches current, "ancestor" if node is ancestor of current, else 'null'.  */
function
scan_toc1 (node, current)
{
  if (node.matches ("a"))
    {
      if (current === node.getAttribute ("href"))
        {
          node.setAttribute ("toc-current", "yes");
          var ul = node.nextElementSibling;
          if (ul && ul.matches ("ul"))
            hide_grand_child_nodes (ul);
          return "current";
        }
    }
  var ancestor = null;
  for (var child = node.firstElementChild; child;
       child = child.nextElementSibling)
    {
      if (scan_toc1 (child, current) !== null)
        {
          ancestor = child;
          break;
        }
    }
  if (ancestor && ancestor.parentNode && ancestor.parentNode.parentNode)
    {
      var pparent = ancestor.parentNode.parentNode;
      for (var sib = pparent.firstElementChild; sib;
           sib = sib.nextElementSibling)
        {
          if (sib !== ancestor.parentNode
              && sib.firstElementChild
              && sib.firstElementChild.nextElementSibling)
            {
              sib.firstElementChild
                .nextElementSibling
                .setAttribute ("toc-detail", "yes");
            }
        }
    }

  return ancestor ? "ancestor" : null;
}

/** Reset what is done by 'scan_toc' and 'hide_grand_child_nodes'.  */
export function
clear_toc_styles (node)
{
  function
  do_clear (node$)
  {
    if (node$.matches ("ul"))
      node$.removeAttribute ("toc-detail");
    else if (node$.matches ("a"))
      node$.removeAttribute ("toc-current");
  }

  depth_first_walk (node, do_clear, Node.ELEMENT_NODE);
}

/** Build the global dictionary containing navigation links from NAV.  NAV
    must be an 'ul' DOM element containing the table of content of the
    manual.  */
export function
create_link_dict (nav)
{
  let prev_id = config.INDEX_ID;
  let links = {};

  function
  add_link (elem)
  {
    if (elem.matches ("a") && elem.hasAttribute ("href"))
      {
        let id = href_hash (elem.getAttribute ("href"));
        links[prev_id] = Object.assign ({}, links[prev_id], { forward: id });
        links[id] = Object.assign ({}, links[id], { backward: prev_id });
        prev_id = id;
      }
  }

  depth_first_walk (nav, add_link, Node.ELEMENT_NODE);
  /* Add a reference to the first and last node of the manual.  */
  links["*TOP*"] = config.INDEX_ID;
  links["*END*"] = prev_id;
  return links;
}

/** Modify LINKS to handle the iframe based navigation properly.  Relative
    links will be opened inside the corresponding iframe and absolute links
    will be opened in a new tab.  LINKS must be an array or a collection of
    nodes.  */
export function
fix_links (links)
{
  for (let i = 0; i < links.length; i += 1)
    {
      let link = links[i];
      let href = link.getAttribute ("href");
      if (href)
        {
          if (absolute_url_p (href))
            link.setAttribute ("target", "_blank");
          else
            link.setAttribute ("href", with_sidebar_query (href));
        }
    }
}