| // storage.js is loaded in the `<head>` 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.querySelector("head > meta[name='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(`<link rel="stylesheet" id="themeStyle" href="${newHref}">`); |
| 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 `<html>` element instead. |
| addClass(document.documentElement, "src-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); |
| } |
| }); |