docs/_includes/sidenav.html

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{% comment %}
==============================================================================
Extract the active nav IDs.
==============================================================================
{% endcomment %}

{% assign active_nav_ids = site.array %}
{% assign parent_id = page.nav-parent_id %}

{% for i in (1..10) %}
  {% if parent_id %}
    {% assign active_nav_ids = active_nav_ids | push: parent_id %}
    {% assign current = (site.pages | where: "nav-id" , parent_id | sort: "nav-pos") %}
    {% if current.size > 0 %}
      {% assign parent_id = current[0].nav-parent_id %}
    {% else %}
      {% break %}
    {% endif %}
  {% else %}
    {% break %}
  {% endif %}
{% endfor %}

{% comment %}
==============================================================================
Build the nested list from nav-id and nav-parent_id relations.
==============================================================================
This builds a nested list from all pages. The fields used to determine the
structure are:

- 'nav-id' => ID of this page. Other pages can use this ID as their
  parent ID.
- 'nav-parent_id' => ID of the parent. This page will be listed under
  the page with id 'nav-parent_id'.

Level 0 is made up of all pages, which have nav-parent_id set to 'root'.

The 'title' of the page is used as the default link text. You can
override this via 'nav-title'. The relative position per navigational
level is determined by 'nav-pos'.
{% endcomment %}

{% assign elementsPosStack = site.array %}
{% assign posStack = site.array %}

{% assign elements = site.array %}
{% assign children = (site.pages | where: "nav-parent_id" , "root" | sort: "nav-pos") %}
{% if children.size > 0 %}
  {% assign elements = elements | push: children %}
{% endif %}

{% assign elementsPos = 0 %}
{% assign pos = 0 %}

<div class="sidenav-logo">
  <p><a href="{{ site.baseurl }}"><img class="bottom" alt="Apache Flink" src="{{ site.baseurl }}/page/img/navbar-brand-logo.jpg"></a> v{{ site.version_title }}</p>
</div>
<ul id="sidenav">
{% for i in (1..10000) %}
  {% if pos >= elements[elementsPos].size %}
    {% if elementsPos == 0 %}
      {% break %}
    {% else %}
      {% assign elementsPos = elementsPosStack | last %}
      {% assign pos = posStack | last %}
</li></ul></div>
      {% assign elementsPosStack = elementsPosStack | pop %}
      {% assign posStack = posStack | pop %}
    {% endif %}
  {% else %}
    {% assign this = elements[elementsPos][pos] %}

    {% if this.url == page.url %}
      {% assign active = true %}
    {% elsif this.nav-id and active_nav_ids contains this.nav-id %}
      {% assign active = true %}
    {% else %}
      {% assign active = false %}
    {% endif %}

    {% capture title %}{% if this.nav-title %}{{ this.nav-title }}{% else %}{{ this.title }}{% endif %}{% endcapture %}
    {% capture target %}"{{ site.baseurl }}{{ this.url }}"{% if active %} class="active"{% endif %}{% endcapture %}
    {% capture overview_target %}"{{ site.baseurl }}{{ this.url }}"{% if this.url == page.url %} class="active"{% endif %}{% endcapture %}

    {% if this.section-break %}<hr class="section-break"></hr>{% endif %}

    {% assign pos = pos | plus: 1 %}
    {% if this.nav-id %}
      {% assign children = (site.pages | where: "nav-parent_id" , this.nav-id | sort: "nav-pos") %}
      {% if children.size > 0 %}
        {% capture collapse_target %}"#collapse-{{ i }}" data-toggle="collapse"{% if active %} class="active"{% endif %}{% endcapture %}
        {% capture expand %}{% unless active %} <i class="fa fa-caret-down pull-right" aria-hidden="true" style="padding-top: 4px"></i>{% endunless %}{% endcapture %}
<li><a href={{ collapse_target }}>{{ title }}{{ expand }}</a><div class="collapse{% if active %} in{% endif %}" id="collapse-{{ i }}"><ul>
  {% if this.nav-show_overview %}<li><a href={{ overview_target }}>Overview</a></li>{% endif %}
        {% assign elements = elements | push: children %}
        {% assign elementsPosStack = elementsPosStack | push: elementsPos %}
        {% assign posStack = posStack | push: pos %}

        {% assign elementsPos = elements.size | minus: 1 %}
        {% assign pos = 0 %}
      {% else %}
<li><a href={{ target }}>{{ title }}</a></li>
      {% endif %}
    {% else %}
<li><a href={{ target }}>{{ title }}</a></li>
    {% endif %}
  {% endif %}
{% endfor %}
</ul>

<div class="sidenav-search-box">
  <form class="navbar-form" role="search" action="{{site.baseurl}}/search-results.html">
    <div class="form-group">
      <input type="text" class="form-control" size="16px" name="q" placeholder="Search">
    </div>
    <button type="submit" class="btn btn-default">Go</button>
  </form>
</div>

<div class="sidenav-versions">
  <div class="dropdown">
    <button class="btn btn-default dropdown-toggle" type="button" data-toggle="dropdown">Pick Docs Version
    <span class="caret"></span></button>
    <ul class="dropdown-menu">
      {% for d in site.previous_docs %}
      <li><a href="{{ d[1] }}">v{{ d[0] }}</a></li>
      {% endfor %}
    </ul>
  </div>
</div>