src/librustdoc/html/static/js/storage.js

   1 // From rust:
   2 /* global resourcesSuffix */
   3 var darkThemes = ["dark", "ayu"];
   4 window.currentTheme = document.getElementById("themeStyle");
   5 window.mainTheme = document.getElementById("mainThemeStyle");
   6
   7 var settingsDataset = (function () {
   8     var settingsElement = document.getElementById("default-settings");
   9     if (settingsElement === null) {
  10         return null;
  11     }
  12     var dataset = settingsElement.dataset;
  13     if (dataset === undefined) {
  14         return null;
  15     }
  16     return dataset;
  17 })();
  18
  19 function getSettingValue(settingName) {
  20     var current = getCurrentValue('rustdoc-' + settingName);
  21     if (current !== null) {
  22         return current;
  23     }
  24     if (settingsDataset !== null) {
  25         // See the comment for `default_settings.into_iter()` etc. in
  26         // `Options::from_matches` in `librustdoc/config.rs`.
  27         var def = settingsDataset[settingName.replace(/-/g,'_')];
  28         if (def !== undefined) {
  29             return def;
  30         }
  31     }
  32     return null;
  33 }
  34
  35 var localStoredTheme = getSettingValue("theme");
  36
  37 var savedHref = [];
  38
  39 // eslint-disable-next-line no-unused-vars
  40 function hasClass(elem, className) {
  41     return elem && elem.classList && elem.classList.contains(className);
  42 }
  43
  44 // eslint-disable-next-line no-unused-vars
  45 function addClass(elem, className) {
  46     if (!elem || !elem.classList) {
  47         return;
  48     }
  49     elem.classList.add(className);
  50 }
  51
  52 // eslint-disable-next-line no-unused-vars
  53 function removeClass(elem, className) {
  54     if (!elem || !elem.classList) {
  55         return;
  56     }
  57     elem.classList.remove(className);
  58 }
  59
  60 function onEach(arr, func, reversed) {
  61     if (arr && arr.length > 0 && func) {
  62         var length = arr.length;
  63         var i;
  64         if (reversed) {
  65             for (i = length - 1; i >= 0; --i) {
  66                 if (func(arr[i])) {
  67                     return true;
  68                 }
  69             }
  70         } else {
  71             for (i = 0; i < length; ++i) {
  72                 if (func(arr[i])) {
  73                     return true;
  74                 }
  75             }
  76         }
  77     }
  78     return false;
  79 }
  80
  81 function onEachLazy(lazyArray, func, reversed) {
  82     return onEach(
  83         Array.prototype.slice.call(lazyArray),
  84         func,
  85         reversed);
  86 }
  87
  88 // eslint-disable-next-line no-unused-vars
  89 function hasOwnPropertyRustdoc(obj, property) {
  90     return Object.prototype.hasOwnProperty.call(obj, property);
  91 }
  92
  93 function updateLocalStorage(name, value) {
  94     try {
  95         window.localStorage.setItem(name, value);
  96     } catch(e) {
  97         // localStorage is not accessible, do nothing
  98     }
  99 }
 100
 101 function getCurrentValue(name) {
 102     try {
 103         return window.localStorage.getItem(name);
 104     } catch(e) {
 105         return null;
 106     }
 107 }
 108
 109 function switchTheme(styleElem, mainStyleElem, newTheme, saveTheme) {
 110     var fullBasicCss = "rustdoc" + resourcesSuffix + ".css";
 111     var fullNewTheme = newTheme + resourcesSuffix + ".css";
 112     var newHref = mainStyleElem.href.replace(fullBasicCss, fullNewTheme);
 113
 114     // If this new value comes from a system setting or from the previously
 115     // saved theme, no need to save it.
 116     if (saveTheme) {
 117         updateLocalStorage("rustdoc-theme", newTheme);
 118     }
 119
 120     if (styleElem.href === newHref) {
 121         return;
 122     }
 123
 124     var found = false;
 125     if (savedHref.length === 0) {
 126         onEachLazy(document.getElementsByTagName("link"), function(el) {
 127             savedHref.push(el.href);
 128         });
 129     }
 130     onEach(savedHref, function(el) {
 131         if (el === newHref) {
 132             found = true;
 133             return true;
 134         }
 135     });
 136     if (found) {
 137         styleElem.href = newHref;
 138     }
 139 }
 140
 141 // This function is called from "main.js".
 142 // eslint-disable-next-line no-unused-vars
 143 function useSystemTheme(value) {
 144     if (value === undefined) {
 145         value = true;
 146     }
 147
 148     updateLocalStorage("rustdoc-use-system-theme", value);
 149
 150     // update the toggle if we're on the settings page
 151     var toggle = document.getElementById("use-system-theme");
 152     if (toggle && toggle instanceof HTMLInputElement) {
 153         toggle.checked = value;
 154     }
 155 }
 156
 157 var updateSystemTheme = (function() {
 158     if (!window.matchMedia) {
 159         // fallback to the CSS computed value
 160         return function() {
 161             var cssTheme = getComputedStyle(document.documentElement)
 162                 .getPropertyValue('content');
 163
 164             switchTheme(
 165                 window.currentTheme,
 166                 window.mainTheme,
 167                 JSON.parse(cssTheme) || "light",
 168                 true
 169             );
 170         };
 171     }
 172
 173     // only listen to (prefers-color-scheme: dark) because light is the default
 174     var mql = window.matchMedia("(prefers-color-scheme: dark)");
 175
 176     function handlePreferenceChange(mql) {
 177         // maybe the user has disabled the setting in the meantime!
 178         if (getSettingValue("use-system-theme") !== "false") {
 179             var lightTheme = getSettingValue("preferred-light-theme") || "light";
 180             var darkTheme = getSettingValue("preferred-dark-theme") || "dark";
 181
 182             if (mql.matches) {
 183                 // prefers a dark theme
 184                 switchTheme(window.currentTheme, window.mainTheme, darkTheme, true);
 185             } else {
 186                 // prefers a light theme, or has no preference
 187                 switchTheme(window.currentTheme, window.mainTheme, lightTheme, true);
 188             }
 189
 190             // note: we save the theme so that it doesn't suddenly change when
 191             // the user disables "use-system-theme" and reloads the page or
 192             // navigates to another page
 193         }
 194     }
 195
 196     mql.addListener(handlePreferenceChange);
 197
 198     return function() {
 199         handlePreferenceChange(mql);
 200     };
 201 })();
 202
 203 if (getSettingValue("use-system-theme") !== "false" && window.matchMedia) {
 204     // update the preferred dark theme if the user is already using a dark theme
 205     // See https://github.com/rust-lang/rust/pull/77809#issuecomment-707875732
 206     if (getSettingValue("use-system-theme") === null
 207         && getSettingValue("preferred-dark-theme") === null
 208         && darkThemes.indexOf(localStoredTheme) >= 0) {
 209         updateLocalStorage("rustdoc-preferred-dark-theme", localStoredTheme);
 210     }
 211
 212     // call the function to initialize the theme at least once!
 213     updateSystemTheme();
 214 } else {
 215     switchTheme(
 216         window.currentTheme,
 217         window.mainTheme,
 218         getSettingValue("theme") || "light",
 219         false
 220     );
 221 }