switchers.js

(function () {
  "use strict";

  if (!String.prototype.startsWith) {
    Object.defineProperty(String.prototype, "startsWith", {
      value: function (search, rawPos) {
        var pos = rawPos > 0 ? rawPos | 0 : 0;
        return this.substring(pos, pos + search.length) === search;
      },
    });
  }

  // Parses versions in URL segments like:
  // "3", "dev", "release/2.7" or "3.6rc2"
  var version_regexs = [
    "(?:\\d)",
    "(?:\\d\\.\\d[\\w\\d\\.]*)",
    "(?:dev)",
    "(?:release/\\d.\\d[\\x\\d\\.]*)",
  ];

  var all_versions = {
    3.11: "dev (3.11)",
    "3.10": "pre (3.10)",
    3.9: "3.9",
    3.8: "3.8",
    3.7: "3.7",
    3.6: "3.6",
    3.5: "3.5",
    2.7: "2.7",
  };
  var all_languages = {
    en: "English",
    es: "Spanish",
    fr: "French",
    ja: "Japanese",
    ko: "Korean",
    "pt-br": "Brazilian Portuguese",
    "zh-cn": "Simplified Chinese",
    "zh-tw": "Traditional Chinese",
  };

  function quote_attr(str) {
    return '"' + str.replace('"', '\\"') + '"';
  }

  function build_version_select(release) {
    var buf = ['<select id="version_select">'];
    var major_minor = release.split(".").slice(0, 2).join(".");

    $.each(all_versions, function (version, title) {
      if (version == major_minor)
        buf.push(
          "<option value=" +
            quote_attr(version) +
            ' selected="selected">' +
            release +
            "</option>"
        );
      else
        buf.push(
          "<option value=" + quote_attr(version) + ">" + title + "</option>"
        );
    });

    buf.push("</select>");
    return buf.join("");
  }

  function build_language_select(current_language) {
    var buf = ['<select id="language_select">'];

    $.each(all_languages, function (language, title) {
      if (language == current_language)
        buf.push(
          '<option value="' +
            language +
            '" selected="selected">' +
            all_languages[current_language] +
            "</option>"
        );
      else buf.push('<option value="' + language + '">' + title + "</option>");
    });
    if (!(current_language in all_languages)) {
      // In case we're browsing a language that is not yet in all_languages.
      buf.push(
        '<option value="' +
          current_language +
          '" selected="selected">' +
          current_language +
          "</option>"
      );
      all_languages[current_language] = current_language;
    }
    buf.push("</select>");
    return buf.join("");
  }

  function navigate_to_first_existing(urls) {
    // Navigate to the first existing URL in urls.
    var url = urls.shift();
    if (urls.length == 0 || url.startsWith("file:///")) {
      window.location.href = url;
      return;
    }
    $.ajax({
      url: url,
      success: function () {
        window.location.href = url;
      },
      error: function () {
        navigate_to_first_existing(urls);
      },
    });
  }

  function on_version_switch() {
    var selected_version =
      $(this).children("option:selected").attr("value") + "/";
    var url = window.location.href;
    var current_language = language_segment_from_url();
    var current_version = version_segment_from_url();
    var new_url = url.replace(
      "/" + current_language + current_version,
      "/" + current_language + selected_version
    );
    if (new_url != url) {
      navigate_to_first_existing([
        new_url,
        url.replace(
          "/" + current_language + current_version,
          "/" + selected_version
        ),
        "/" + current_language + selected_version,
        "/" + selected_version,
        "/",
      ]);
    }
  }

  function on_language_switch() {
    var selected_language =
      $(this).children("option:selected").attr("value") + "/";
    var url = window.location.href;
    var current_language = language_segment_from_url();
    var current_version = version_segment_from_url();
    if (selected_language == "en/")
      // Special 'default' case for english.
      selected_language = "";
    var new_url = url.replace(
      "/" + current_language + current_version,
      "/" + selected_language + current_version
    );
    if (new_url != url) {
      navigate_to_first_existing([new_url, "/"]);
    }
  }

  // Returns the path segment of the language as a string, like 'fr/'
  // or '' if not found.
  function language_segment_from_url() {
    var path = window.location.pathname;
    var language_regexp =
      "/((?:" + Object.keys(all_languages).join("|") + ")/)";
    var match = path.match(language_regexp);
    if (match !== null) return match[1];
    return "";
  }

  // Returns the path segment of the version as a string, like '3.6/'
  // or '' if not found.
  function version_segment_from_url() {
    var path = window.location.pathname;
    var language_segment = language_segment_from_url();
    var version_segment = "(?:(?:" + version_regexs.join("|") + ")/)";
    var version_regexp = language_segment + "(" + version_segment + ")";
    var match = path.match(version_regexp);
    if (match !== null) return match[1];
    return "";
  }

  function create_placeholders_if_missing() {
    var version_segment = version_segment_from_url();
    var language_segment = language_segment_from_url();
    var index = "/" + language_segment + version_segment;

    if ($(".version_switcher_placeholder").length) return;

    var html =
      '<span class="language_switcher_placeholder"></span> \
<span class="version_switcher_placeholder"></span> \
<a href="/" id="indexlink">Documentation</a> &#187;';

    var probable_places = [
      "body>div.related>ul>li:not(.right):contains('Documentation'):first",
      "body>div.related>ul>li:not(.right):contains('documentation'):first",
    ];

    for (var i = 0; i < probable_places.length; i++) {
      var probable_place = $(probable_places[i]);
      if (probable_place.length == 1) {
        probable_place.html(html);
        document.getElementById("indexlink").href = index;
        return;
      }
    }
  }

  $(document).ready(function () {
    var language_segment = language_segment_from_url();
    var current_language = language_segment.replace(/\/+$/g, "") || "en";
    var version_select = build_version_select(DOCUMENTATION_OPTIONS.VERSION);

    create_placeholders_if_missing();
    $(".version_switcher_placeholder").html(version_select);
    $(".version_switcher_placeholder select").bind("change", on_version_switch);

    var language_select = build_language_select(current_language);

    $(".language_switcher_placeholder").html(language_select);
    $(".language_switcher_placeholder select").bind(
      "change",
      on_language_switch
    );
  });
})();