// 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"); const settingsDataset = (function() { const settingsElement = document.getElementById("default-settings"); return settingsElement && settingsElement.dataset ? settingsElement.dataset : null; })(); function getSettingValue(settingName) { const current = getCurrentValue(settingName); if (current === null && 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 current; } const localStoredTheme = getSettingValue("theme"); // eslint-disable-next-line no-unused-vars function hasClass(elem, className) { return elem && elem.classList && elem.classList.contains(className); } function addClass(elem, className) { if (elem && elem.classList) { elem.classList.add(className); } } // eslint-disable-next-line no-unused-vars function removeClass(elem, className) { if (elem && elem.classList) { 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) { if (reversed) { for (let i = arr.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 */ // eslint-disable-next-line no-unused-vars 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; } } // Get a value from the rustdoc-vars div, which is used to convey data from // Rust to the JS. If there is no such element, return null. const getVar = (function getVar(name) { const el = document.getElementById("rustdoc-vars"); return el ? el.attributes["data-" + name].value : null; }); function switchTheme(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); } let newHref; if (newThemeName === "light" || newThemeName === "dark" || newThemeName === "ayu") { newHref = getVar("static-root-path") + getVar("theme-" + newThemeName + "-css"); } else { newHref = getVar("root-path") + newThemeName + getVar("resource-suffix") + ".css"; } if (!window.currentTheme) { document.write(``); window.currentTheme = document.getElementById("themeStyle"); } else if (newHref !== window.currentTheme.href) { window.currentTheme.href = newHref; } } const updateTheme = (function() { // only listen to (prefers-color-scheme: dark) because light is the default const mql = window.matchMedia("(prefers-color-scheme: dark)"); /** * Update the current theme to match whatever the current combination of * * the preference for using the system theme * (if this is the case, the value of preferred-light-theme, if the * system theme is light, otherwise if dark, the value of * preferred-dark-theme.) * * the preferred theme * … dictates that it should be. */ function updateTheme() { // 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"; updateLocalStorage("use-system-theme", "true"); // use light theme if user prefers it, or has no preference switchTheme(mql.matches ? darkTheme : lightTheme, true); // 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 { switchTheme(getSettingValue("theme"), false); } } mql.addEventListener("change", updateTheme); return updateTheme; })(); 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); } } updateTheme(); 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(updateTheme, 0); } });