src/librustdoc/html/static/storage.js

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