src/librustdoc/html/static/storage.js

   1 // From rust:
   2 /* global resourcesSuffix */
   3
   4 var currentTheme = document.getElementById("themeStyle");
   5 var mainTheme = document.getElementById("mainThemeStyle");
   6
   7 var savedHref = [];
   8
   9 function hasClass(elem, className) {
  10     return elem && elem.classList && elem.classList.contains(className);
  11 }
  12
  13 function addClass(elem, className) {
  14     if (!elem || !elem.classList) {
  15         return;
  16     }
  17     elem.classList.add(className);
  18 }
  19
  20 function removeClass(elem, className) {
  21     if (!elem || !elem.classList) {
  22         return;
  23     }
  24     elem.classList.remove(className);
  25 }
  26
  27 function onEach(arr, func, reversed) {
  28     if (arr && arr.length > 0 && func) {
  29         var length = arr.length;
  30         if (reversed !== true) {
  31             for (var i = 0; i < length; ++i) {
  32                 if (func(arr[i]) === true) {
  33                     return true;
  34                 }
  35             }
  36         } else {
  37             for (var i = length - 1; i >= 0; --i) {
  38                 if (func(arr[i]) === true) {
  39                     return true;
  40                 }
  41             }
  42         }
  43     }
  44     return false;
  45 }
  46
  47 function onEachLazy(lazyArray, func, reversed) {
  48     return onEach(
  49         Array.prototype.slice.call(lazyArray),
  50         func,
  51         reversed);
  52 }
  53
  54 function usableLocalStorage() {
  55     // Check if the browser supports localStorage at all:
  56     if (typeof Storage === "undefined") {
  57         return false;
  58     }
  59     // Check if we can access it; this access will fail if the browser
  60     // preferences deny access to localStorage, e.g., to prevent storage of
  61     // "cookies" (or cookie-likes, as is the case here).
  62     try {
  63         return window.localStorage !== null && window.localStorage !== undefined;
  64     } catch(err) {
  65         // Storage is supported, but browser preferences deny access to it.
  66         return false;
  67     }
  68 }
  69
  70 function updateLocalStorage(name, value) {
  71     if (usableLocalStorage()) {
  72         localStorage[name] = value;
  73     } else {
  74         // No Web Storage support so we do nothing
  75     }
  76 }
  77
  78 function getCurrentValue(name) {
  79     if (usableLocalStorage() && localStorage[name] !== undefined) {
  80         return localStorage[name];
  81     }
  82     return null;
  83 }
  84
  85 function switchTheme(styleElem, mainStyleElem, newTheme, saveTheme) {
  86     var fullBasicCss = "rustdoc" + resourcesSuffix + ".css";
  87     var fullNewTheme = newTheme + resourcesSuffix + ".css";
  88     var newHref = mainStyleElem.href.replace(fullBasicCss, fullNewTheme);
  89
  90     if (styleElem.href === newHref) {
  91         return;
  92     }
  93
  94     var found = false;
  95     if (savedHref.length === 0) {
  96         onEachLazy(document.getElementsByTagName("link"), function(el) {
  97             savedHref.push(el.href);
  98         });
  99     }
 100     onEach(savedHref, function(el) {
 101         if (el === newHref) {
 102             found = true;
 103             return true;
 104         }
 105     });
 106     if (found === true) {
 107         styleElem.href = newHref;
 108         // If this new value comes from a system setting or from the previously saved theme, no
 109         // need to save it.
 110         if (saveTheme === true) {
 111             updateLocalStorage("rustdoc-theme", newTheme);
 112         }
 113     }
 114 }
 115
 116 function getSystemValue() {
 117     var property = getComputedStyle(document.documentElement).getPropertyValue('content');
 118     return property.replace(/[\"\']/g, "");
 119 }
 120
 121 switchTheme(currentTheme, mainTheme,
 122             getCurrentValue("rustdoc-theme") || getSystemValue() || "light",
 123             false);