// storage.js is loaded in the `` of all rustdoc pages and doesn't // use `async` or `defer`. That means it blocks further parsing and rendering // of the page: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script. // This makes it the correct place to act on settings that affect the display of // the page, so we don't see major layout changes during the load of the page. "use strict"; const darkThemes = ["dark", "ayu"]; window.currentTheme = document.getElementById("themeStyle"); window.mainTheme = document.getElementById("mainThemeStyle"); // WARNING: RUSTDOC_MOBILE_BREAKPOINT MEDIA QUERY // If you update this line, then you also need to update the media query with the same // warning in rustdoc.css window.RUSTDOC_MOBILE_BREAKPOINT = 700; const settingsDataset = (function() { const settingsElement = document.getElementById("default-settings"); if (settingsElement === null) { return null; } const dataset = settingsElement.dataset; if (dataset === undefined) { return null; } return dataset; })(); function getSettingValue(settingName) { const current = getCurrentValue(settingName); if (current !== null) { return current; } if (settingsDataset !== null) { // See the comment for `default_settings.into_iter()` etc. in // `Options::from_matches` in `librustdoc/config.rs`. const def = settingsDataset[settingName.replace(/-/g,"_")]; if (def !== undefined) { return def; } } return null; } const localStoredTheme = getSettingValue("theme"); const savedHref = []; // eslint-disable-next-line no-unused-vars function hasClass(elem, className) { return elem && elem.classList && elem.classList.contains(className); } // eslint-disable-next-line no-unused-vars function addClass(elem, className) { if (!elem || !elem.classList) { return; } elem.classList.add(className); } // eslint-disable-next-line no-unused-vars function removeClass(elem, className) { if (!elem || !elem.classList) { return; } elem.classList.remove(className); } /** * Run a callback for every element of an Array. * @param {Array} arr - The array to iterate over * @param {function(?)} func - The callback * @param {boolean} [reversed] - Whether to iterate in reverse */ function onEach(arr, func, reversed) { if (arr && arr.length > 0 && func) { if (reversed) { const length = arr.length; for (let i = length - 1; i >= 0; --i) { if (func(arr[i])) { return true; } } } else { for (const elem of arr) { if (func(elem)) { return true; } } } } return false; } /** * Turn an HTMLCollection or a NodeList into an Array, then run a callback * for every element. This is useful because iterating over an HTMLCollection * or a "live" NodeList while modifying it can be very slow. * https://developer.mozilla.org/en-US/docs/Web/API/HTMLCollection * https://developer.mozilla.org/en-US/docs/Web/API/NodeList * @param {NodeList|HTMLCollection} lazyArray - An array to iterate over * @param {function(?)} func - The callback * @param {boolean} [reversed] - Whether to iterate in reverse */ function onEachLazy(lazyArray, func, reversed) { return onEach( Array.prototype.slice.call(lazyArray), func, reversed); } function updateLocalStorage(name, value) { try { window.localStorage.setItem("rustdoc-" + name, value); } catch (e) { // localStorage is not accessible, do nothing } } function getCurrentValue(name) { try { return window.localStorage.getItem("rustdoc-" + name); } catch (e) { return null; } } function switchTheme(styleElem, mainStyleElem, newThemeName, saveTheme) { // If this new value comes from a system setting or from the previously // saved theme, no need to save it. if (saveTheme) { updateLocalStorage("theme", newThemeName); } if (savedHref.length === 0) { onEachLazy(document.getElementsByTagName("link"), el => { savedHref.push(el.href); }); } const newHref = savedHref.find(url => { const m = url.match(/static\.files\/(.*)-[a-f0-9]{16}\.css$/); if (m && m[1] === newThemeName) { return true; } const m2 = url.match(/\/([^/]*)\.css$/); if (m2 && m2[1].startsWith(newThemeName)) { return true; } }); if (newHref && newHref !== styleElem.href) { styleElem.href = newHref; } } // This function is called from "main.js". // eslint-disable-next-line no-unused-vars function useSystemTheme(value) { if (value === undefined) { value = true; } updateLocalStorage("use-system-theme", value); // update the toggle if we're on the settings page const toggle = document.getElementById("use-system-theme"); if (toggle && toggle instanceof HTMLInputElement) { toggle.checked = value; } } const updateSystemTheme = (function() { if (!window.matchMedia) { // fallback to the CSS computed value return () => { const cssTheme = getComputedStyle(document.documentElement) .getPropertyValue("content"); switchTheme( window.currentTheme, window.mainTheme, JSON.parse(cssTheme) || "light", true ); }; } // only listen to (prefers-color-scheme: dark) because light is the default const mql = window.matchMedia("(prefers-color-scheme: dark)"); function handlePreferenceChange(mql) { const use = theme => { switchTheme(window.currentTheme, window.mainTheme, theme, true); }; // maybe the user has disabled the setting in the meantime! if (getSettingValue("use-system-theme") !== "false") { const lightTheme = getSettingValue("preferred-light-theme") || "light"; const darkTheme = getSettingValue("preferred-dark-theme") || "dark"; if (mql.matches) { use(darkTheme); } else { // prefers a light theme, or has no preference use(lightTheme); } // note: we save the theme so that it doesn't suddenly change when // the user disables "use-system-theme" and reloads the page or // navigates to another page } else { use(getSettingValue("theme")); } } mql.addListener(handlePreferenceChange); return () => { handlePreferenceChange(mql); }; })(); function switchToSavedTheme() { switchTheme( window.currentTheme, window.mainTheme, getSettingValue("theme") || "light", false ); } if (getSettingValue("use-system-theme") !== "false" && window.matchMedia) { // update the preferred dark theme if the user is already using a dark theme // See https://github.com/rust-lang/rust/pull/77809#issuecomment-707875732 if (getSettingValue("use-system-theme") === null && getSettingValue("preferred-dark-theme") === null && darkThemes.indexOf(localStoredTheme) >= 0) { updateLocalStorage("preferred-dark-theme", localStoredTheme); } // call the function to initialize the theme at least once! updateSystemTheme(); } else { switchToSavedTheme(); } if (getSettingValue("source-sidebar-show") === "true") { // At this point in page load, `document.body` is not available yet. // Set a class on the `` element instead. addClass(document.documentElement, "source-sidebar-expanded"); } // If we navigate away (for example to a settings page), and then use the back or // forward button to get back to a page, the theme may have changed in the meantime. // But scripts may not be re-loaded in such a case due to the bfcache // (https://web.dev/bfcache/). The "pageshow" event triggers on such navigations. // Use that opportunity to update the theme. // We use a setTimeout with a 0 timeout here to put the change on the event queue. // For some reason, if we try to change the theme while the `pageshow` event is // running, it sometimes fails to take effect. The problem manifests on Chrome, // specifically when talking to a remote website with no caching. window.addEventListener("pageshow", ev => { if (ev.persisted) { setTimeout(switchToSavedTheme, 0); } });