main.js

// Local js definitions:
/* global addClass, getSettingValue, hasClass, searchState */
/* global onEach, onEachLazy, removeClass */

"use strict";

// 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.
function getVar(name) {
    const el = document.getElementById("rustdoc-vars");
    if (el) {
        return el.attributes["data-" + name].value;
    } else {
        return null;
    }
}

// Given a basename (e.g. "storage") and an extension (e.g. ".js"), return a URL
// for a resource under the root-path, with the resource-suffix.
function resourcePath(basename, extension) {
    return getVar("root-path") + basename + getVar("resource-suffix") + extension;
}

function hideMain() {
    addClass(document.getElementById(MAIN_ID), "hidden");
}

function showMain() {
    removeClass(document.getElementById(MAIN_ID), "hidden");
}

function elemIsInParent(elem, parent) {
    while (elem && elem !== document.body) {
        if (elem === parent) {
            return true;
        }
        elem = elem.parentElement;
    }
    return false;
}

function blurHandler(event, parentElem, hideCallback) {
    if (!elemIsInParent(document.activeElement, parentElem) &&
        !elemIsInParent(event.relatedTarget, parentElem)
    ) {
        hideCallback();
    }
}

window.rootPath = getVar("root-path");
window.currentCrate = getVar("current-crate");

function setMobileTopbar() {
    // FIXME: It would be nicer to generate this text content directly in HTML,
    // but with the current code it's hard to get the right information in the right place.
    const mobileLocationTitle = document.querySelector(".mobile-topbar h2");
    const locationTitle = document.querySelector(".sidebar h2.location");
    if (mobileLocationTitle && locationTitle) {
        mobileLocationTitle.innerHTML = locationTitle.innerHTML;
    }
}

// Gets the human-readable string for the virtual-key code of the
// given KeyboardEvent, ev.
//
// This function is meant as a polyfill for KeyboardEvent#key,
// since it is not supported in IE 11 or Chrome for Android. We also test for
// KeyboardEvent#keyCode because the handleShortcut handler is
// also registered for the keydown event, because Blink doesn't fire
// keypress on hitting the Escape key.
//
// So I guess you could say things are getting pretty interoperable.
function getVirtualKey(ev) {
    if ("key" in ev && typeof ev.key !== "undefined") {
        return ev.key;
    }

    const c = ev.charCode || ev.keyCode;
    if (c === 27) {
        return "Escape";
    }
    return String.fromCharCode(c);
}

const MAIN_ID = "main-content";
const SETTINGS_BUTTON_ID = "settings-menu";
const ALTERNATIVE_DISPLAY_ID = "alternative-display";
const NOT_DISPLAYED_ID = "not-displayed";
const HELP_BUTTON_ID = "help-button";

function getSettingsButton() {
    return document.getElementById(SETTINGS_BUTTON_ID);
}

function getHelpButton() {
    return document.getElementById(HELP_BUTTON_ID);
}

// Returns the current URL without any query parameter or hash.
function getNakedUrl() {
    return window.location.href.split("?")[0].split("#")[0];
}

/**
 * This function inserts `newNode` after `referenceNode`. It doesn't work if `referenceNode`
 * doesn't have a parent node.
 *
 * @param {HTMLElement} newNode
 * @param {HTMLElement} referenceNode
 */
function insertAfter(newNode, referenceNode) {
    referenceNode.parentNode.insertBefore(newNode, referenceNode.nextSibling);
}

/**
 * This function creates a new `<section>` with the given `id` and `classes` if it doesn't already
 * exist.
 *
 * More information about this in `switchDisplayedElement` documentation.
 *
 * @param {string} id
 * @param {string} classes
 */
function getOrCreateSection(id, classes) {
    let el = document.getElementById(id);

    if (!el) {
        el = document.createElement("section");
        el.id = id;
        el.className = classes;
        insertAfter(el, document.getElementById(MAIN_ID));
    }
    return el;
}

/**
 * Returns the `<section>` element which contains the displayed element.
 *
 * @return {HTMLElement}
 */
function getAlternativeDisplayElem() {
    return getOrCreateSection(ALTERNATIVE_DISPLAY_ID, "content hidden");
}

/**
 * Returns the `<section>` element which contains the not-displayed elements.
 *
 * @return {HTMLElement}
 */
function getNotDisplayedElem() {
    return getOrCreateSection(NOT_DISPLAYED_ID, "hidden");
}

/**
 * To nicely switch between displayed "extra" elements (such as search results or settings menu)
 * and to alternate between the displayed and not displayed elements, we hold them in two different
 * `<section>` elements. They work in pair: one holds the hidden elements while the other
 * contains the displayed element (there can be only one at the same time!). So basically, we switch
 * elements between the two `<section>` elements.
 *
 * @param {HTMLElement} elemToDisplay
 */
function switchDisplayedElement(elemToDisplay) {
    const el = getAlternativeDisplayElem();

    if (el.children.length > 0) {
        getNotDisplayedElem().appendChild(el.firstElementChild);
    }
    if (elemToDisplay === null) {
        addClass(el, "hidden");
        showMain();
        return;
    }
    el.appendChild(elemToDisplay);
    hideMain();
    removeClass(el, "hidden");
}

function browserSupportsHistoryApi() {
    return window.history && typeof window.history.pushState === "function";
}

// eslint-disable-next-line no-unused-vars
function loadCss(cssUrl) {
    const link = document.createElement("link");
    link.href = cssUrl;
    link.type = "text/css";
    link.rel = "stylesheet";
    document.getElementsByTagName("head")[0].appendChild(link);
}

(function() {
    const isHelpPage = window.location.pathname.endsWith("/help.html");

    function loadScript(url) {
        const script = document.createElement("script");
        script.src = url;
        document.head.append(script);
    }

    getSettingsButton().onclick = event => {
        if (event.ctrlKey || event.altKey || event.metaKey) {
            return;
        }
        window.hideAllModals(false);
        addClass(getSettingsButton(), "rotate");
        event.preventDefault();
        // Sending request for the CSS and the JS files at the same time so it will
        // hopefully be loaded when the JS will generate the settings content.
        loadCss(getVar("static-root-path") + getVar("settings-css"));
        loadScript(getVar("static-root-path") + getVar("settings-js"));
    };

    window.searchState = {
        loadingText: "Loading search results...",
        input: document.getElementsByClassName("search-input")[0],
        outputElement: () => {
            let el = document.getElementById("search");
            if (!el) {
                el = document.createElement("section");
                el.id = "search";
                getNotDisplayedElem().appendChild(el);
            }
            return el;
        },
        title: document.title,
        titleBeforeSearch: document.title,
        timeout: null,
        // On the search screen, so you remain on the last tab you opened.
        //
        // 0 for "In Names"
        // 1 for "In Parameters"
        // 2 for "In Return Types"
        currentTab: 0,
        // tab and back preserves the element that was focused.
        focusedByTab: [null, null, null],
        clearInputTimeout: () => {
            if (searchState.timeout !== null) {
                clearTimeout(searchState.timeout);
                searchState.timeout = null;
            }
        },
        isDisplayed: () => searchState.outputElement().parentElement.id === ALTERNATIVE_DISPLAY_ID,
        // Sets the focus on the search bar at the top of the page
        focus: () => {
            searchState.input.focus();
        },
        // Removes the focus from the search bar.
        defocus: () => {
            searchState.input.blur();
        },
        showResults: search => {
            if (search === null || typeof search === "undefined") {
                search = searchState.outputElement();
            }
            switchDisplayedElement(search);
            searchState.mouseMovedAfterSearch = false;
            document.title = searchState.title;
        },
        hideResults: () => {
            switchDisplayedElement(null);
            document.title = searchState.titleBeforeSearch;
            // We also remove the query parameter from the URL.
            if (browserSupportsHistoryApi()) {
                history.replaceState(null, window.currentCrate + " - Rust",
                    getNakedUrl() + window.location.hash);
            }
        },
        getQueryStringParams: () => {
            const params = {};
            window.location.search.substring(1).split("&").
                map(s => {
                    const pair = s.split("=");
                    params[decodeURIComponent(pair[0])] =
                        typeof pair[1] === "undefined" ? null : decodeURIComponent(pair[1]);
                });
            return params;
        },
        setup: () => {
            const search_input = searchState.input;
            if (!searchState.input) {
                return;
            }
            let searchLoaded = false;
            function loadSearch() {
                if (!searchLoaded) {
                    searchLoaded = true;
                    loadScript(getVar("static-root-path") + getVar("search-js"));
                    loadScript(resourcePath("search-index", ".js"));
                }
            }

            search_input.addEventListener("focus", () => {
                search_input.origPlaceholder = search_input.placeholder;
                search_input.placeholder = "Type your search here.";
                loadSearch();
            });

            if (search_input.value !== "") {
                loadSearch();
            }

            const params = searchState.getQueryStringParams();
            if (params.search !== undefined) {
                searchState.setLoadingSearch();
                loadSearch();
            }
        },
        setLoadingSearch: () => {
            const search = searchState.outputElement();
            search.innerHTML = "<h3 class=\"search-loading\">" + searchState.loadingText + "</h3>";
            searchState.showResults(search);
        },
    };

    function getPageId() {
        if (window.location.hash) {
            const tmp = window.location.hash.replace(/^#/, "");
            if (tmp.length > 0) {
                return tmp;
            }
        }
        return null;
    }

    const toggleAllDocsId = "toggle-all-docs";
    let savedHash = "";

    function handleHashes(ev) {
        if (ev !== null && searchState.isDisplayed() && ev.newURL) {
            // This block occurs when clicking on an element in the navbar while
            // in a search.
            switchDisplayedElement(null);
            const hash = ev.newURL.slice(ev.newURL.indexOf("#") + 1);
            if (browserSupportsHistoryApi()) {
                // `window.location.search`` contains all the query parameters, not just `search`.
                history.replaceState(null, "",
                    getNakedUrl() + window.location.search + "#" + hash);
            }
            const elem = document.getElementById(hash);
            if (elem) {
                elem.scrollIntoView();
            }
        }
        // This part is used in case an element is not visible.
        if (savedHash !== window.location.hash) {
            savedHash = window.location.hash;
            if (savedHash.length === 0) {
                return;
            }
            expandSection(savedHash.slice(1)); // we remove the '#'
        }
    }

    function onHashChange(ev) {
        // If we're in mobile mode, we should hide the sidebar in any case.
        hideSidebar();
        handleHashes(ev);
    }

    function openParentDetails(elem) {
        while (elem) {
            if (elem.tagName === "DETAILS") {
                elem.open = true;
            }
            elem = elem.parentNode;
        }
    }

    function expandSection(id) {
        openParentDetails(document.getElementById(id));
    }

    function handleEscape(ev) {
        searchState.clearInputTimeout();
        switchDisplayedElement(null);
        if (browserSupportsHistoryApi()) {
            history.replaceState(null, window.currentCrate + " - Rust",
                getNakedUrl() + window.location.hash);
        }
        ev.preventDefault();
        searchState.defocus();
        window.hideAllModals(true); // true = reset focus for notable traits
    }

    function handleShortcut(ev) {
        // Don't interfere with browser shortcuts
        const disableShortcuts = getSettingValue("disable-shortcuts") === "true";
        if (ev.ctrlKey || ev.altKey || ev.metaKey || disableShortcuts) {
            return;
        }

        if (document.activeElement.tagName === "INPUT" &&
            document.activeElement.type !== "checkbox") {
            switch (getVirtualKey(ev)) {
            case "Escape":
                handleEscape(ev);
                break;
            }
        } else {
            switch (getVirtualKey(ev)) {
            case "Escape":
                handleEscape(ev);
                break;

            case "s":
            case "S":
                ev.preventDefault();
                searchState.focus();
                break;

            case "+":
                ev.preventDefault();
                expandAllDocs();
                break;
            case "-":
                ev.preventDefault();
                collapseAllDocs();
                break;

            case "?":
                showHelp();
                break;

            default:
                break;
            }
        }
    }

    document.addEventListener("keypress", handleShortcut);
    document.addEventListener("keydown", handleShortcut);

    function addSidebarItems() {
        if (!window.SIDEBAR_ITEMS) {
            return;
        }
        const sidebar = document.getElementsByClassName("sidebar-elems")[0];

        /**
         * Append to the sidebar a "block" of links - a heading along with a list (`<ul>`) of items.
         *
         * @param {string} shortty - A short type name, like "primitive", "mod", or "macro"
         * @param {string} id - The HTML id of the corresponding section on the module page.
         * @param {string} longty - A long, capitalized, plural name, like "Primitive Types",
         *                          "Modules", or "Macros".
         */
        function block(shortty, id, longty) {
            const filtered = window.SIDEBAR_ITEMS[shortty];
            if (!filtered) {
                return;
            }

            const h3 = document.createElement("h3");
            h3.innerHTML = `<a href="index.html#${id}">${longty}</a>`;
            const ul = document.createElement("ul");
            ul.className = "block " + shortty;

            for (const item of filtered) {
                const name = item[0];
                const desc = item[1]; // can be null

                let path;
                if (shortty === "mod") {
                    path = name + "/index.html";
                } else {
                    path = shortty + "." + name + ".html";
                }
                const current_page = document.location.href.split("/").pop();
                const link = document.createElement("a");
                link.href = path;
                link.title = desc;
                if (path === current_page) {
                    link.className = "current";
                }
                link.textContent = name;
                const li = document.createElement("li");
                li.appendChild(link);
                ul.appendChild(li);
            }
            sidebar.appendChild(h3);
            sidebar.appendChild(ul);
        }

        if (sidebar) {
            block("primitive", "primitives", "Primitive Types");
            block("mod", "modules", "Modules");
            block("macro", "macros", "Macros");
            block("struct", "structs", "Structs");
            block("enum", "enums", "Enums");
            block("union", "unions", "Unions");
            block("constant", "constants", "Constants");
            block("static", "static", "Statics");
            block("trait", "traits", "Traits");
            block("fn", "functions", "Functions");
            block("type", "types", "Type Definitions");
            block("foreigntype", "foreign-types", "Foreign Types");
            block("keyword", "keywords", "Keywords");
            block("traitalias", "trait-aliases", "Trait Aliases");
        }
    }

    window.register_implementors = imp => {
        const implementors = document.getElementById("implementors-list");
        const synthetic_implementors = document.getElementById("synthetic-implementors-list");
        const inlined_types = new Set();

        const TEXT_IDX = 0;
        const SYNTHETIC_IDX = 1;
        const TYPES_IDX = 2;

        if (synthetic_implementors) {
            // This `inlined_types` variable is used to avoid having the same implementation
            // showing up twice. For example "String" in the "Sync" doc page.
            //
            // By the way, this is only used by and useful for traits implemented automatically
            // (like "Send" and "Sync").
            onEachLazy(synthetic_implementors.getElementsByClassName("impl"), el => {
                const aliases = el.getAttribute("data-aliases");
                if (!aliases) {
                    return;
                }
                aliases.split(",").forEach(alias => {
                    inlined_types.add(alias);
                });
            });
        }

        let currentNbImpls = implementors.getElementsByClassName("impl").length;
        const traitName = document.querySelector("h1.fqn > .trait").textContent;
        const baseIdName = "impl-" + traitName + "-";
        const libs = Object.getOwnPropertyNames(imp);
        // We don't want to include impls from this JS file, when the HTML already has them.
        // The current crate should always be ignored. Other crates that should also be
        // ignored are included in the attribute `data-ignore-extern-crates`.
        const script = document
            .querySelector("script[data-ignore-extern-crates]");
        const ignoreExternCrates = script ? script.getAttribute("data-ignore-extern-crates") : "";
        for (const lib of libs) {
            if (lib === window.currentCrate || ignoreExternCrates.indexOf(lib) !== -1) {
                continue;
            }
            const structs = imp[lib];

            struct_loop:
            for (const struct of structs) {
                const list = struct[SYNTHETIC_IDX] ? synthetic_implementors : implementors;

                // The types list is only used for synthetic impls.
                // If this changes, `main.js` and `write_shared.rs` both need changed.
                if (struct[SYNTHETIC_IDX]) {
                    for (const struct_type of struct[TYPES_IDX]) {
                        if (inlined_types.has(struct_type)) {
                            continue struct_loop;
                        }
                        inlined_types.add(struct_type);
                    }
                }

                const code = document.createElement("h3");
                code.innerHTML = struct[TEXT_IDX];
                addClass(code, "code-header");

                onEachLazy(code.getElementsByTagName("a"), elem => {
                    const href = elem.getAttribute("href");

                    if (href && href.indexOf("http") !== 0) {
                        elem.setAttribute("href", window.rootPath + href);
                    }
                });

                const currentId = baseIdName + currentNbImpls;
                const anchor = document.createElement("a");
                anchor.href = "#" + currentId;
                addClass(anchor, "anchor");

                const display = document.createElement("div");
                display.id = currentId;
                addClass(display, "impl");
                display.appendChild(anchor);
                display.appendChild(code);
                list.appendChild(display);
                currentNbImpls += 1;
            }
        }
    };
    if (window.pending_implementors) {
        window.register_implementors(window.pending_implementors);
    }

    function addSidebarCrates() {
        if (!window.ALL_CRATES) {
            return;
        }
        const sidebarElems = document.getElementsByClassName("sidebar-elems")[0];
        if (!sidebarElems) {
            return;
        }
        // Draw a convenient sidebar of known crates if we have a listing
        const h3 = document.createElement("h3");
        h3.innerHTML = "Crates";
        const ul = document.createElement("ul");
        ul.className = "block crate";

        for (const crate of window.ALL_CRATES) {
            const link = document.createElement("a");
            link.href = window.rootPath + crate + "/index.html";
            if (window.rootPath !== "./" && crate === window.currentCrate) {
                link.className = "current";
            }
            link.textContent = crate;

            const li = document.createElement("li");
            li.appendChild(link);
            ul.appendChild(li);
        }
        sidebarElems.appendChild(h3);
        sidebarElems.appendChild(ul);
    }

    function expandAllDocs() {
        const innerToggle = document.getElementById(toggleAllDocsId);
        removeClass(innerToggle, "will-expand");
        onEachLazy(document.getElementsByClassName("rustdoc-toggle"), e => {
            if (!hasClass(e, "type-contents-toggle")) {
                e.open = true;
            }
        });
        innerToggle.title = "collapse all docs";
        innerToggle.children[0].innerText = "\u2212"; // "\u2212" is "−" minus sign
    }

    function collapseAllDocs() {
        const innerToggle = document.getElementById(toggleAllDocsId);
        addClass(innerToggle, "will-expand");
        onEachLazy(document.getElementsByClassName("rustdoc-toggle"), e => {
            if (e.parentNode.id !== "implementations-list" ||
                (!hasClass(e, "implementors-toggle") &&
                 !hasClass(e, "type-contents-toggle"))
            ) {
                e.open = false;
            }
        });
        innerToggle.title = "expand all docs";
        innerToggle.children[0].innerText = "+";
    }

    function toggleAllDocs() {
        const innerToggle = document.getElementById(toggleAllDocsId);
        if (!innerToggle) {
            return;
        }
        if (hasClass(innerToggle, "will-expand")) {
            expandAllDocs();
        } else {
            collapseAllDocs();
        }
    }

    (function() {
        const toggles = document.getElementById(toggleAllDocsId);
        if (toggles) {
            toggles.onclick = toggleAllDocs;
        }

        const hideMethodDocs = getSettingValue("auto-hide-method-docs") === "true";
        const hideImplementations = getSettingValue("auto-hide-trait-implementations") === "true";
        const hideLargeItemContents = getSettingValue("auto-hide-large-items") !== "false";

        function setImplementorsTogglesOpen(id, open) {
            const list = document.getElementById(id);
            if (list !== null) {
                onEachLazy(list.getElementsByClassName("implementors-toggle"), e => {
                    e.open = open;
                });
            }
        }

        if (hideImplementations) {
            setImplementorsTogglesOpen("trait-implementations-list", false);
            setImplementorsTogglesOpen("blanket-implementations-list", false);
        }

        onEachLazy(document.getElementsByClassName("rustdoc-toggle"), e => {
            if (!hideLargeItemContents && hasClass(e, "type-contents-toggle")) {
                e.open = true;
            }
            if (hideMethodDocs && hasClass(e, "method-toggle")) {
                e.open = false;
            }

        });

        const pageId = getPageId();
        if (pageId !== null) {
            expandSection(pageId);
        }
    }());

    window.rustdoc_add_line_numbers_to_examples = () => {
        onEachLazy(document.getElementsByClassName("rust-example-rendered"), x => {
            const parent = x.parentNode;
            const line_numbers = parent.querySelectorAll(".example-line-numbers");
            if (line_numbers.length > 0) {
                return;
            }
            const count = x.textContent.split("\n").length;
            const elems = [];
            for (let i = 0; i < count; ++i) {
                elems.push(i + 1);
            }
            const node = document.createElement("pre");
            addClass(node, "example-line-numbers");
            node.innerHTML = elems.join("\n");
            parent.insertBefore(node, x);
        });
    };

    window.rustdoc_remove_line_numbers_from_examples = () => {
        onEachLazy(document.getElementsByClassName("rust-example-rendered"), x => {
            const parent = x.parentNode;
            const line_numbers = parent.querySelectorAll(".example-line-numbers");
            for (const node of line_numbers) {
                parent.removeChild(node);
            }
        });
    };

    if (getSettingValue("line-numbers") === "true") {
        window.rustdoc_add_line_numbers_to_examples();
    }

    let oldSidebarScrollPosition = null;

    // Scroll locking used both here and in source-script.js

    window.rustdocMobileScrollLock = function() {
        const mobile_topbar = document.querySelector(".mobile-topbar");
        if (window.innerWidth <= window.RUSTDOC_MOBILE_BREAKPOINT) {
            // This is to keep the scroll position on mobile.
            oldSidebarScrollPosition = window.scrollY;
            document.body.style.width = `${document.body.offsetWidth}px`;
            document.body.style.position = "fixed";
            document.body.style.top = `-${oldSidebarScrollPosition}px`;
            if (mobile_topbar) {
                mobile_topbar.style.top = `${oldSidebarScrollPosition}px`;
                mobile_topbar.style.position = "relative";
            }
        } else {
            oldSidebarScrollPosition = null;
        }
    };

    window.rustdocMobileScrollUnlock = function() {
        const mobile_topbar = document.querySelector(".mobile-topbar");
        if (oldSidebarScrollPosition !== null) {
            // This is to keep the scroll position on mobile.
            document.body.style.width = "";
            document.body.style.position = "";
            document.body.style.top = "";
            if (mobile_topbar) {
                mobile_topbar.style.top = "";
                mobile_topbar.style.position = "";
            }
            // The scroll position is lost when resetting the style, hence why we store it in
            // `oldSidebarScrollPosition`.
            window.scrollTo(0, oldSidebarScrollPosition);
            oldSidebarScrollPosition = null;
        }
    };

    function showSidebar() {
        window.hideAllModals(false);
        window.rustdocMobileScrollLock();
        const sidebar = document.getElementsByClassName("sidebar")[0];
        addClass(sidebar, "shown");
    }

    function hideSidebar() {
        window.rustdocMobileScrollUnlock();
        const sidebar = document.getElementsByClassName("sidebar")[0];
        removeClass(sidebar, "shown");
    }

    window.addEventListener("resize", () => {
        if (window.innerWidth > window.RUSTDOC_MOBILE_BREAKPOINT &&
            oldSidebarScrollPosition !== null) {
            // If the user opens the sidebar in "mobile" mode, and then grows the browser window,
            // we need to switch away from mobile mode and make the main content area scrollable.
            hideSidebar();
        }
        if (window.CURRENT_NOTABLE_ELEMENT) {
            // As a workaround to the behavior of `contains: layout` used in doc togglers, the
            // notable traits popup is positioned using javascript.
            //
            // This means when the window is resized, we need to redo the layout.
            const base = window.CURRENT_NOTABLE_ELEMENT.NOTABLE_BASE;
            const force_visible = base.NOTABLE_FORCE_VISIBLE;
            hideNotable(false);
            if (force_visible) {
                showNotable(base);
                base.NOTABLE_FORCE_VISIBLE = true;
            }
        }
    });

    function handleClick(id, f) {
        const elem = document.getElementById(id);
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