main.js

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

"use strict";

if (!String.prototype.startsWith) {
    String.prototype.startsWith = function(searchString, position) {
        position = position || 0;
        return this.indexOf(searchString, position) === position;
    };
}
if (!String.prototype.endsWith) {
    String.prototype.endsWith = function(suffix, length) {
        const l = length || this.length;
        return this.indexOf(suffix, l - suffix.length) !== -1;
    };
}

if (!DOMTokenList.prototype.add) {
    DOMTokenList.prototype.add = function(className) {
        if (className && !hasClass(this, className)) {
            if (this.className && this.className.length > 0) {
                this.className += " " + className;
            } else {
                this.className = className;
            }
        }
    };
}

if (!DOMTokenList.prototype.remove) {
    DOMTokenList.prototype.remove = function(className) {
        if (className && this.className) {
            this.className = (" " + this.className + " ").replace(" " + className + " ", " ")
                                                         .trim();
        }
    };
}

// 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 () {
    window.rootPath = getVar("root-path");
    window.currentCrate = getVar("current-crate");
    window.searchJS =  resourcePath("search", ".js");
    window.searchIndexJS = resourcePath("search-index", ".js");
    window.settingsJS = resourcePath("settings", ".js");
    const sidebarVars = document.getElementById("sidebar-vars");
    if (sidebarVars) {
        window.sidebarCurrent = {
            name: sidebarVars.attributes["data-name"].value,
            ty: sidebarVars.attributes["data-ty"].value,
            relpath: sidebarVars.attributes["data-relpath"].value,
        };
        // 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.location");
        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";

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

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

window.hideSettings = () => {
    // Does nothing by default.
};

/**
 * 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(cssFileName) {
    const link = document.createElement("link");
    link.href = resourcePath(cssFileName, ".css");
    link.type = "text/css";
    link.rel = "stylesheet";
    document.getElementsByTagName("head")[0].appendChild(link);
}

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

    getSettingsButton().onclick = event => {
        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("settings");
        loadScript(window.settingsJS);
    };

    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(window.searchJS);
                    loadScript(window.searchIndexJS);
                }
            }

            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) {
                const search = searchState.outputElement();
                search.innerHTML = "<h3 class=\"search-loading\">" +
                    searchState.loadingText + "</h3>";
                searchState.showResults(search);
                loadSearch();
            }
        },
    };

    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.
        const sidebar = document.getElementsByClassName("sidebar")[0];
        removeClass(sidebar, "shown");
        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 getHelpElement(build) {
        if (build) {
            buildHelperPopup();
        }
        return document.getElementById("help");
    }

    /**
     * Show the help popup.
     *
     * @param {boolean} display    - Whether to show or hide the popup
     * @param {Event}   ev         - The event that triggered this call
     * @param {Element} [help]     - The help element if it already exists
     */
    function displayHelp(display, ev, help) {
        if (display) {
            help = help ? help : getHelpElement(true);
            if (hasClass(help, "hidden")) {
                ev.preventDefault();
                removeClass(help, "hidden");
                addClass(document.body, "blur");
            }
        } else {
            // No need to build the help popup if we want to hide it in case it hasn't been
            // built yet...
            help = help ? help : getHelpElement(false);
            if (help && !hasClass(help, "hidden")) {
                ev.preventDefault();
                addClass(help, "hidden");
                removeClass(document.body, "blur");
            }
        }
    }

    function handleEscape(ev) {
        searchState.clearInputTimeout();
        const help = getHelpElement(false);
        if (help && !hasClass(help, "hidden")) {
            displayHelp(false, ev, help);
        } else {
            switchDisplayedElement(null);
            if (browserSupportsHistoryApi()) {
                history.replaceState(null, window.currentCrate + " - Rust",
                    getNakedUrl() + window.location.hash);
            }
            ev.preventDefault();
        }
        searchState.defocus();
        window.hideSettings();
    }

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

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

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

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

            case "?":
                displayHelp(true, ev);
                break;

            default:
                break;
            }
        }
    }

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

    // delayed sidebar rendering.
    window.initSidebarItems = items => {
        const sidebar = document.getElementsByClassName("sidebar-elems")[0];
        let others;
        const current = window.sidebarCurrent;

        function addSidebarCrates(crates) {
            if (!hasClass(document.body, "crate")) {
                // We only want to list crates on the crate page.
                return;
            }
            // Draw a convenient sidebar of known crates if we have a listing
            const div = document.createElement("div");
            div.className = "block crate";
            div.innerHTML = "<h3>Crates</h3>";
            const ul = document.createElement("ul");
            div.appendChild(ul);

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

                const li = document.createElement("li");
                li.appendChild(link);
                ul.appendChild(li);
            }
            others.appendChild(div);
        }

        /**
         * 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 = items[shortty];
            if (!filtered) {
                return;
            }

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

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

                let klass = shortty;
                if (name === current.name && shortty === current.ty) {
                    klass += " current";
                }
                let path;
                if (shortty === "mod") {
                    path = name + "/index.html";
                } else {
                    path = shortty + "." + name + ".html";
                }
                const link = document.createElement("a");
                link.href = current.relpath + path;
                link.title = desc;
                link.className = klass;
                link.textContent = name;
                const li = document.createElement("li");
                li.appendChild(link);
                ul.appendChild(li);
            }
            div.appendChild(ul);
            others.appendChild(div);
        }

        if (sidebar) {
            others = document.createElement("div");
            others.className = "others";
            sidebar.appendChild(others);

            const isModule = hasClass(document.body, "mod");
            if (!isModule) {
                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");
            }

            // `crates{version}.js` should always be loaded before this script, so we can use
            // it safely.
            addSidebarCrates(window.ALL_CRATES);
        }
    };

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

        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 > .in-band > .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 ignoreExternCrates = document
            .querySelector("script[data-ignore-extern-crates]")
            .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 ? synthetic_implementors : implementors;

                if (struct.synthetic) {
                    for (const struct_type of struct.types) {
                        if (inlined_types.has(struct_type)) {
                            continue struct_loop;
                        }
                        inlined_types.add(struct_type);
                    }
                }

                const code = document.createElement("h3");
                code.innerHTML = struct.text;
                addClass(code, "code-header");
                addClass(code, "in-band");

                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 labelForToggleButton(sectionIsCollapsed) {
        if (sectionIsCollapsed) {
            // button will expand the section
            return "+";
        }
        // button will collapse the section
        // note that this text is also set in the HTML template in ../render/mod.rs
        return "\u2212"; // "\u2212" is "−" minus sign
    }

    function toggleAllDocs() {
        const innerToggle = document.getElementById(toggleAllDocsId);
        if (!innerToggle) {
            return;
        }
        let sectionIsCollapsed = false;
        if (hasClass(innerToggle, "will-expand")) {
            removeClass(innerToggle, "will-expand");
            onEachLazy(document.getElementsByClassName("rustdoc-toggle"), e => {
                if (!hasClass(e, "type-contents-toggle")) {
                    e.open = true;
                }
            });
            innerToggle.title = "collapse all docs";
        } else {
            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;
                }
            });
            sectionIsCollapsed = true;
            innerToggle.title = "expand all docs";
        }
        innerToggle.children[0].innerText = labelForToggleButton(sectionIsCollapsed);
    }

    (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);
        }
    }());

    (function() {
        // To avoid checking on "rustdoc-line-numbers" value on every loop...
        let lineNumbersFunc = () => {};
        if (getSettingValue("line-numbers") === "true") {
            lineNumbersFunc = x => {
                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, "line-number");
                node.innerHTML = elems.join("\n");
                x.parentNode.insertBefore(node, x);
            };
        }
        onEachLazy(document.getElementsByClassName("rust-example-rendered"), e => {
            if (hasClass(e, "compile_fail")) {
                e.addEventListener("mouseover", function() {
                    this.parentElement.previousElementSibling.childNodes[0].style.color = "#f00";
                });
                e.addEventListener("mouseout", function() {
                    this.parentElement.previousElementSibling.childNodes[0].style.color = "";
                });
            } else if (hasClass(e, "ignore")) {
                e.addEventListener("mouseover", function() {
                    this.parentElement.previousElementSibling.childNodes[0].style.color = "#ff9200";
                });
                e.addEventListener("mouseout", function() {
                    this.parentElement.previousElementSibling.childNodes[0].style.color = "";
                });
            }
            lineNumbersFunc(e);
        });
    }());

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

    function handleClick(id, f) {
        const elem = document.getElementById(id);
        if (elem) {
            elem.addEventListener("click", f);
        }
    }
    handleClick("help-button", ev => {
        displayHelp(true, ev);
    });
    handleClick(MAIN_ID, () => {
        hideSidebar();
    });

    onEachLazy(document.getElementsByTagName("a"), el => {
        // For clicks on internal links (<A> tags with a hash property), we expand the section we're
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    window.addEventListener("hashchange", onHashChange);
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