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