sphinx: Enhance the sphinx experience/nagivation with:

* Remove the pointless looking parts of breadcrumb navigtation
* Add a document type switcher to the breadcrumb navigation
* Add a version selection switch to the breadcrumb navigation

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>

4 files changed, 264 insertions, 0 deletions

diff --git a/doc/_templates/breadcrumbs.html b/doc/_templates/breadcrumbs.html
new file mode 100644
index 000000000..eb6244b74
--- /dev/null
+++ b/doc/_templates/breadcrumbs.html
@@ -0,0 +1,14 @@
+{% extends "!breadcrumbs.html" %}
+
+{% block breadcrumbs %}
+    <li>
+      <span class="doctype_switcher_placeholder">{{ doctype or 'single' }}</span>
+      <span class="version_switcher_placeholder">{{ release }}</span>
+    </li>
+    <li> &raquo;</li>
+    {% for doc in parents %}
+      <li><a href="{{ doc.link|e }}">{{ doc.title }}</a> &raquo;</li>
+    {% endfor %}
+    <li>{{ title }}</li>
+{% endblock %}
+
diff --git a/doc/_templates/layout.html b/doc/_templates/layout.html
new file mode 100644
index 000000000..308d5c7a2
--- /dev/null
+++ b/doc/_templates/layout.html
@@ -0,0 +1,7 @@
+{% extends "!layout.html" %}
+
+{% block extrabody %}
+<div id="outdated-warning" style="text-align: center; background-color: #FFBABA; color: #6A0E0E;">
+</div>
+{% endblock %}
+
diff --git a/doc/conf.py b/doc/conf.py
index 4ff90e8db..722c79230 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -16,6 +16,15 @@
 
 import datetime
 
+current_version = "dev"
+
+# String used in sidebar
+version = 'Version: ' + current_version
+if current_version == 'dev':
+    version = 'Version: Current Development'
+# Version seen in documentation_options.js and hence in js switchers code
+release = current_version
+
 # -- Project information -----------------------------------------------------
 
 project = 'Bitbake'
@@ -67,6 +76,7 @@ html_static_path = ['sphinx-static']
 
 # Add customm CSS and JS files
 html_css_files = ['theme_overrides.css']
+html_js_files = ['switchers.js']
 
 # Hide 'Created using Sphinx' text
 html_show_sphinx = False
diff --git a/doc/sphinx-static/switchers.js b/doc/sphinx-static/switchers.js
new file mode 100644
index 000000000..c8a94d93b
--- /dev/null
+++ b/doc/sphinx-static/switchers.js
@@ -0,0 +1,233 @@
+(function() {
+  'use strict';
+
+  var all_versions = {
+    'dev': 'dev (3.2)',
+    '3.1.2': '3.1.2',
+    '3.0.3': '3.0.3',
+    '2.7.4': '2.7.4',
+  };
+
+  var all_doctypes = {
+      'single': 'Individual Webpages',
+      'mega': "All-in-one 'Mega' Manual",
+  };
+
+  // Simple version comparision
+  // Return 1 if a > b
+  // Return -1 if a < b
+  // Return 0 if a == b
+  function ver_compare(a, b) {
+    if (a == "dev") {
+       return 1;
+    }
+
+    if (a === b) {
+       return 0;
+    }
+
+    var a_components = a.split(".");
+    var b_components = b.split(".");
+
+    var len = Math.min(a_components.length, b_components.length);
+
+    // loop while the components are equal
+    for (var i = 0; i < len; i++) {
+        // A bigger than B
+        if (parseInt(a_components[i]) > parseInt(b_components[i])) {
+            return 1;
+        }
+
+        // B bigger than A
+        if (parseInt(a_components[i]) < parseInt(b_components[i])) {
+            return -1;
+        }
+    }
+
+    // If one's a prefix of the other, the longer one is greater.
+    if (a_components.length > b_components.length) {
+        return 1;
+    }
+
+    if (a_components.length < b_components.length) {
+        return -1;
+    }
+
+    // Otherwise they are the same.
+    return 0;
+  }
+
+  function build_version_select(current_series, current_version) {
+    var buf = ['<select>'];
+
+    $.each(all_versions, function(version, title) {
+      var series = version.substr(0, 3);
+      if (series == current_series) {
+        if (version == current_version)
+            buf.push('<option value="' + version + '" selected="selected">' + title + '</option>');
+        else
+            buf.push('<option value="' + version + '">' + title + '</option>');
+
+        if (version != current_version)
+            buf.push('<option value="' + current_version + '" selected="selected">' + current_version + '</option>');
+      } else {
+        buf.push('<option value="' + version + '">' + title + '</option>');
+      }
+    });
+
+    buf.push('</select>');
+    return buf.join('');
+  }
+
+  function build_doctype_select(current_doctype) {
+    var buf = ['<select>'];
+
+    $.each(all_doctypes, function(doctype, title) {
+      if (doctype == current_doctype)
+        buf.push('<option value="' + doctype + '" selected="selected">' +
+                 all_doctypes[current_doctype] + '</option>');
+      else
+        buf.push('<option value="' + doctype + '">' + title + '</option>');
+    });
+    if (!(current_doctype in all_doctypes)) {
+        // In case we're browsing a doctype that is not yet in all_doctypes.
+        buf.push('<option value="' + current_doctype + '" selected="selected">' +
+                 current_doctype + '</option>');
+        all_doctypes[current_doctype] = current_doctype;
+    }
+    buf.push('</select>');
+    return buf.join('');
+  }
+
+  function navigate_to_first_existing(urls) {
+    // Navigate to the first existing URL in urls.
+    var url = urls.shift();
+
+    // Web browsers won't redirect file:// urls to file urls using ajax but
+    // its useful for local testing
+    if (url.startsWith("file://")) {
+      window.location.href = url;
+      return;
+    }
+
+    if (urls.length == 0) {
+      window.location.href = url;
+      return;
+    }
+    $.ajax({
+      url: url,
+      success: function() {
+        window.location.href = url;
+      },
+      error: function() {
+        navigate_to_first_existing(urls);
+      }
+    });
+  }
+
+  function get_docroot_url() {
+    var url = window.location.href;
+    var root = DOCUMENTATION_OPTIONS.URL_ROOT;
+
+    var urlarray = url.split('/');
+    // Trim off anything after '/'
+    urlarray.pop();
+    var depth = (root.match(/\.\.\//g) || []).length;
+    for (var i = 0; i < depth; i++) {
+      urlarray.pop();
+    }
+
+    return urlarray.join('/') + '/';
+  }
+
+  function on_version_switch() {
+    var selected_version = $(this).children('option:selected').attr('value');
+    var url = window.location.href;
+    var current_version = DOCUMENTATION_OPTIONS.VERSION;
+    var docroot = get_docroot_url()
+
+    var new_versionpath = selected_version + '/';
+    if (selected_version == "dev")
+        new_versionpath = '';
+
+    // dev versions have no version prefix
+    if (current_version == "dev") {
+        var new_url = docroot + new_versionpath + url.replace(docroot, "");
+        var fallback_url = docroot + new_versionpath;
+    } else {
+        var new_url = url.replace('/' + current_version + '/', '/' + new_versionpath);
+        var fallback_url = new_url.replace(url.replace(docroot, ""), "");
+    }
+
+    console.log(get_docroot_url())
+    console.log(url + " to url " + new_url);
+    console.log(url + " to fallback " + fallback_url);
+
+    if (new_url != url) {
+      navigate_to_first_existing([
+        new_url,
+        fallback_url,
+        'https://www.yoctoproject.org/docs/',
+      ]);
+    }
+  }
+
+  function on_doctype_switch() {
+    var selected_doctype = $(this).children('option:selected').attr('value');
+    var url = window.location.href;
+    if (selected_doctype == 'mega') {
+      var docroot = get_docroot_url()
+      var current_version = DOCUMENTATION_OPTIONS.VERSION;
+      // Assume manuals before 3.2 are using old docbook mega-manual
+      if (ver_compare(current_version, "3.2") < 0) {
+        var new_url = docroot + "/mega-manual/mega-manual.html";
+      } else {
+        var new_url = docroot + "/singleindex.html";
+      }
+    } else {
+      var new_url = url.replace("/singleindex.html", "/index.html")
+    }
+
+    if (new_url != url) {
+      navigate_to_first_existing([
+        new_url,
+        'https://www.yoctoproject.org/docs/',
+      ]);
+    }
+  }
+
+  // Returns the current doctype based upon the url
+  function doctype_segment_from_url(url) {
+    if (url.includes("singleindex") || url.includes("mega-manual"))
+      return "mega";
+    return "single";
+  }
+
+  $(document).ready(function() {
+    var release = DOCUMENTATION_OPTIONS.VERSION;
+    var current_doctype = doctype_segment_from_url(window.location.href);
+    var current_series = release.substr(0, 3);
+    var version_select = build_version_select(current_series, release);
+
+    $('.version_switcher_placeholder').html(version_select);
+    $('.version_switcher_placeholder select').bind('change', on_version_switch);
+
+    var doctype_select = build_doctype_select(current_doctype);
+
+    $('.doctype_switcher_placeholder').html(doctype_select);
+    $('.doctype_switcher_placeholder select').bind('change', on_doctype_switch);
+
+    if (ver_compare(release, "3.1") < 0) {
+      $('#outdated-warning').html('Version ' + release + ' of the project is now considered obsolete, please select and use a more recent version');
+      $('#outdated-warning').css('padding', '.5em');
+    } else if (release != "dev") {
+      $.each(all_versions, function(version, title) {
+        var series = version.substr(0, 3);
+        if (series == current_series && version != release) {
+          $('#outdated-warning').html('This document is for outdated version ' + release + ', you should select the latest release version in this series, ' + version + '.');
+          $('#outdated-warning').css('padding', '.5em');
+        }
+      });
+    }
+  });
+})();