mdBook/src/theme/book.js

"use strict";

// Fix back button cache problem
window.onunload = function () { };

// Global variable, shared between modules
function playpen_text(playpen) {
    let code_block = playpen.querySelector("code");

    if (window.ace && code_block.classList.contains("editable")) {
        let editor = window.ace.edit(code_block);
        return editor.getValue();
    } else {
        return code_block.textContent;
    }
}

(function codeSnippets() {
    // Hide Rust code lines prepended with a specific character
    var hiding_character = "#";

    function fetch_with_timeout(url, options, timeout = 6000) {
        return Promise.race([
            fetch(url, options),
            new Promise((_, reject) => setTimeout(() => reject(new Error('timeout')), timeout))
        ]);
    }

    var playpens = Array.from(document.querySelectorAll(".playpen"));
    if (playpens.length > 0) {
        fetch_with_timeout("https://play.rust-lang.org/meta/crates", {
            headers: {
                'Content-Type': "application/json",
            },
            method: 'POST',
            mode: 'cors',
        })
        .then(response => response.json())
        .then(response => {
            // get list of crates available in the rust playground
            let playground_crates = response.crates.map(item => item["id"]);
            playpens.forEach(block => handle_crate_list_update(block, playground_crates));
        });
    }

    function handle_crate_list_update(playpen_block, playground_crates) {
        // update the play buttons after receiving the response
        update_play_button(playpen_block, playground_crates);

        // and install on change listener to dynamically update ACE editors
        if (window.ace) {
            let code_block = playpen_block.querySelector("code");
            if (code_block.classList.contains("editable")) {
                let editor = window.ace.edit(code_block);
                editor.addEventListener("change", function (e) {
                    update_play_button(playpen_block, playground_crates);
                });
            }
        }
    }

    // updates the visibility of play button based on `no_run` class and
    // used crates vs ones available on http://play.rust-lang.org
    function update_play_button(pre_block, playground_crates) {
        var play_button = pre_block.querySelector(".play-button");

        // skip if code is `no_run`
        if (pre_block.querySelector('code').classList.contains("no_run")) {
            play_button.classList.add("hidden");
            return;
        }

        // get list of `extern crate`'s from snippet
        var txt = playpen_text(pre_block);
        var re = /extern\s+crate\s+([a-zA-Z_0-9]+)\s*;/g;
        var snippet_crates = [];
        var item;
        while (item = re.exec(txt)) {
            snippet_crates.push(item[1]);
        }

        // check if all used crates are available on play.rust-lang.org
        var all_available = snippet_crates.every(function (elem) {
            return playground_crates.indexOf(elem) > -1;
        });

        if (all_available) {
            play_button.classList.remove("hidden");
        } else {
            play_button.classList.add("hidden");
        }
    }

    function run_rust_code(code_block) {
        var result_block = code_block.querySelector(".result");
        if (!result_block) {
            result_block = document.createElement('code');
            result_block.className = 'result hljs language-bash';

            code_block.append(result_block);
        }

        let text = playpen_text(code_block);

        var params = {
            version: "stable",
            optimize: "0",
            code: text
        };

        if (text.indexOf("#![feature") !== -1) {
            params.version = "nightly";
        }

        result_block.innerText = "Running...";

        fetch_with_timeout("https://play.rust-lang.org/evaluate.json", {
            headers: {
                'Content-Type': "application/json",
            },
            method: 'POST',
            mode: 'cors',
            body: JSON.stringify(params)
        })
        .then(response => response.json())
        .then(response => result_block.innerText = response.result)
        .catch(error => result_block.innerText = "Playground Communication: " + error.message);
    }

    // Syntax highlighting Configuration
    hljs.configure({
        tabReplace: '    ', // 4 spaces
        languages: [],      // Languages used for auto-detection
    });

    if (window.ace) {
        // language-rust class needs to be removed for editable
        // blocks or highlightjs will capture events
        Array
            .from(document.querySelectorAll('code.editable'))
            .forEach(function (block) { block.classList.remove('language-rust'); });

        Array
            .from(document.querySelectorAll('code:not(.editable)'))
            .forEach(function (block) { hljs.highlightBlock(block); });
    } else {
        Array
            .from(document.querySelectorAll('code'))
            .forEach(function (block) { hljs.highlightBlock(block); });
    }

    // Adding the hljs class gives code blocks the color css
    // even if highlighting doesn't apply
    Array
        .from(document.querySelectorAll('code'))
        .forEach(function (block) { block.classList.add('hljs'); });

    Array.from(document.querySelectorAll("code.language-rust")).forEach(function (block) {

        var code_block = block;
        var pre_block = block.parentNode;
        // hide lines
        var lines = code_block.innerHTML.split("\n");
        var first_non_hidden_line = false;
        var lines_hidden = false;
        var trimmed_line = "";

        for (var n = 0; n < lines.length; n++) {
            trimmed_line = lines[n].trim();
            if (trimmed_line[0] == hiding_character && trimmed_line[1] != hiding_character) {
                if (first_non_hidden_line) {
                    lines[n] = "<span class=\"hidden\">" + "\n" + lines[n].replace(/(\s*)# ?/, "$1") + "</span>";
                }
                else {
                    lines[n] = "<span class=\"hidden\">" + lines[n].replace(/(\s*)# ?/, "$1") + "\n" + "</span>";
                }
                lines_hidden = true;
            }
            else if (first_non_hidden_line) {
                lines[n] = "\n" + lines[n];
            }
            else {
                first_non_hidden_line = true;
            }
            if (trimmed_line[0] == hiding_character && trimmed_line[1] == hiding_character) {
                lines[n] = lines[n].replace("##", "#")
            }
        }
        code_block.innerHTML = lines.join("");

        // If no lines were hidden, return
        if (!lines_hidden) { return; }

        var buttons = document.createElement('div');
        buttons.className = 'buttons';
        buttons.innerHTML = "<button class=\"fa fa-expand\" title=\"Show hidden lines\" aria-label=\"Show hidden lines\"></button>";

        // add expand button
        pre_block.insertBefore(buttons, pre_block.firstChild);

        pre_block.querySelector('.buttons').addEventListener('click', function (e) {
            if (e.target.classList.contains('fa-expand')) {
                var lines = pre_block.querySelectorAll('span.hidden');

                e.target.classList.remove('fa-expand');
                e.target.classList.add('fa-compress');
                e.target.title = 'Hide lines';
                e.target.setAttribute('aria-label', e.target.title);

                Array.from(lines).forEach(function (line) {
                    line.classList.remove('hidden');
                    line.classList.add('unhidden');
                });
            } else if (e.target.classList.contains('fa-compress')) {
                var lines = pre_block.querySelectorAll('span.unhidden');

                e.target.classList.remove('fa-compress');
                e.target.classList.add('fa-expand');
                e.target.title = 'Show hidden lines';
                e.target.setAttribute('aria-label', e.target.title);

                Array.from(lines).forEach(function (line) {
                    line.classList.remove('unhidden');
                    line.classList.add('hidden');
                });
            }
        });
    });

    Array.from(document.querySelectorAll('pre code')).forEach(function (block) {
        var pre_block = block.parentNode;
        if (!pre_block.classList.contains('playpen')) {
            var buttons = pre_block.querySelector(".buttons");
            if (!buttons) {
                buttons = document.createElement('div');
                buttons.className = 'buttons';
                pre_block.insertBefore(buttons, pre_block.firstChild);
            }

            var clipButton = document.createElement('button');
            clipButton.className = 'fa fa-copy clip-button';
            clipButton.title = 'Copy to clipboard';
            clipButton.setAttribute('aria-label', clipButton.title);
            clipButton.innerHTML = '<i class=\"tooltiptext\"></i>';

            buttons.insertBefore(clipButton, buttons.firstChild);
        }
    });

    // Process playpen code blocks
    Array.from(document.querySelectorAll(".playpen")).forEach(function (pre_block) {
        // Add play button
        var buttons = pre_block.querySelector(".buttons");
        if (!buttons) {
            buttons = document.createElement('div');
            buttons.className = 'buttons';
            pre_block.insertBefore(buttons, pre_block.firstChild);
        }

        var runCodeButton = document.createElement('button');
        runCodeButton.className = 'fa fa-play play-button';
        runCodeButton.hidden = true;
        runCodeButton.title = 'Run this code';
        runCodeButton.setAttribute('aria-label', runCodeButton.title);

        var copyCodeClipboardButton = document.createElement('button');
        copyCodeClipboardButton.className = 'fa fa-copy clip-button';
        copyCodeClipboardButton.innerHTML = '<i class="tooltiptext"></i>';
        copyCodeClipboardButton.title = 'Copy to clipboard';
        copyCodeClipboardButton.setAttribute('aria-label', copyCodeClipboardButton.title);

        buttons.insertBefore(runCodeButton, buttons.firstChild);
        buttons.insertBefore(copyCodeClipboardButton, buttons.firstChild);

        runCodeButton.addEventListener('click', function (e) {
            run_rust_code(pre_block);
        });

        let code_block = pre_block.querySelector("code");
        if (window.ace && code_block.classList.contains("editable")) {
            var undoChangesButton = document.createElement('button');
            undoChangesButton.className = 'fa fa-history reset-button';
            undoChangesButton.title = 'Undo changes';
            undoChangesButton.setAttribute('aria-label', undoChangesButton.title);

            buttons.insertBefore(undoChangesButton, buttons.firstChild);

            undoChangesButton.addEventListener('click', function () {
                let editor = window.ace.edit(code_block);
                editor.setValue(editor.originalCode);
                editor.clearSelection();
            });
        }
    });
})();

(function themes() {
    var html = document.querySelector('html');
    var themeToggleButton = document.getElementById('theme-toggle');
    var themePopup = document.getElementById('theme-list');
    var themeColorMetaTag = document.querySelector('meta[name="theme-color"]');
    var stylesheets = {
        ayuHighlight: document.querySelector("[href$='ayu-highlight.css']"),
        tomorrowNight: document.querySelector("[href$='tomorrow-night.css']"),
        highlight: document.querySelector("[href$='highlight.css']"),
    };

    function showThemes() {
        themePopup.style.display = 'block';
        themeToggleButton.setAttribute('aria-expanded', true);
        themePopup.querySelector("button#" + document.body.className).focus();
    }

    function hideThemes() {
        themePopup.style.display = 'none';
        themeToggleButton.setAttribute('aria-expanded', false);
        themeToggleButton.focus();
    }

    function set_theme(theme) {
        let ace_theme;

        if (theme == 'coal' || theme == 'navy') {
            stylesheets.ayuHighlight.disabled = true;
            stylesheets.tomorrowNight.disabled = false;
            stylesheets.highlight.disabled = true;

            ace_theme = "ace/theme/tomorrow_night";
        } else if (theme == 'ayu') {
            stylesheets.ayuHighlight.disabled = false;
            stylesheets.tomorrowNight.disabled = true;
            stylesheets.highlight.disabled = true;

            ace_theme = "ace/theme/tomorrow_night";
        } else {
            stylesheets.ayuHighlight.disabled = true;
            stylesheets.tomorrowNight.disabled = true;
            stylesheets.highlight.disabled = false;

            ace_theme = "ace/theme/dawn";
        }

        setTimeout(function () {
            themeColorMetaTag.content = getComputedStyle(document.body).backgroundColor;
        }, 1);

        if (window.ace && window.editors) {
            window.editors.forEach(function (editor) {
                editor.setTheme(ace_theme);
            });
        }

        var previousTheme;
        try { previousTheme = localStorage.getItem('mdbook-theme'); } catch (e) { }
        if (previousTheme === null || previousTheme === undefined) { previousTheme = default_theme; }

        try { localStorage.setItem('mdbook-theme', theme); } catch (e) { }

        document.body.className = theme;
        html.classList.remove(previousTheme);
        html.classList.add(theme);
    }

    // Set theme
    var theme;
    try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
    if (theme === null || theme === undefined) { theme = default_theme; }

    set_theme(theme);

    themeToggleButton.addEventListener('click', function () {
        if (themePopup.style.display === 'block') {
            hideThemes();
        } else {
            showThemes();
        }
    });

    themePopup.addEventListener('click', function (e) {
        var theme = e.target.id || e.target.parentElement.id;
        set_theme(theme);
    });

    themePopup.addEventListener('focusout', function(e) {
        // e.relatedTarget is null in Safari and Firefox on macOS (see workaround below)
        if (!!e.relatedTarget && !themeToggleButton.contains(e.relatedTarget) && !themePopup.contains(e.relatedTarget)) {
            hideThemes();
        }
    });

    // Should not be needed, but it works around an issue on macOS & iOS: https://github.com/rust-lang-nursery/mdBook/issues/628
    document.addEventListener('click', function(e) {
        if (themePopup.style.display === 'block' && !themeToggleButton.contains(e.target) && !themePopup.contains(e.target)) {
            hideThemes();
        }
    });

    document.addEventListener('keydown', function (e) {
        if (e.altKey || e.ctrlKey || e.metaKey || e.shiftKey) { return; }
        if (!themePopup.contains(e.target)) { return; }

        switch (e.key) {
            case 'Escape':
                e.preventDefault();
                hideThemes();
                break;
            case 'ArrowUp':
                e.preventDefault();
                var li = document.activeElement.parentElement;
                if (li && li.previousElementSibling) {
                    li.previousElementSibling.querySelector('button').focus();
                }
                break;
            case 'ArrowDown':
                e.preventDefault();
                var li = document.activeElement.parentElement;
                if (li && li.nextElementSibling) {
                    li.nextElementSibling.querySelector('button').focus();
                }
                break;
            case 'Home':
                e.preventDefault();
                themePopup.querySelector('li:first-child button').focus();
                break;
            case 'End':
                e.preventDefault();
                themePopup.querySelector('li:last-child button').focus();
                break;
        }
    });
})();

(function sidebar() {
    var html = document.querySelector("html");
    var sidebar = document.getElementById("sidebar");
    var sidebarLinks = document.querySelectorAll('#sidebar a');
    var sidebarToggleButton = document.getElementById("sidebar-toggle");
    var firstContact = null;

    function showSidebar() {
        html.classList.remove('sidebar-hidden')
        html.classList.add('sidebar-visible');
        Array.from(sidebarLinks).forEach(function (link) {
            link.setAttribute('tabIndex', 0);
        });
        sidebarToggleButton.setAttribute('aria-expanded', true);
        sidebar.setAttribute('aria-hidden', false);
        try { localStorage.setItem('mdbook-sidebar', 'visible'); } catch (e) { }
    }

    function hideSidebar() {
        html.classList.remove('sidebar-visible')
        html.classList.add('sidebar-hidden');
        Array.from(sidebarLinks).forEach(function (link) {
            link.setAttribute('tabIndex', -1);
        });
        sidebarToggleButton.setAttribute('aria-expanded', false);
        sidebar.setAttribute('aria-hidden', true);
        try { localStorage.setItem('mdbook-sidebar', 'hidden'); } catch (e) { }
    }

    // Toggle sidebar
    sidebarToggleButton.addEventListener('click', function sidebarToggle() {
        if (html.classList.contains("sidebar-hidden")) {
            showSidebar();
        } else if (html.classList.contains("sidebar-visible")) {
            hideSidebar();
        } else {
            if (getComputedStyle(sidebar)['transform'] === 'none') {
                hideSidebar();
            } else {
                showSidebar();
            }
        }
    });

    document.addEventListener('touchstart', function (e) {
        firstContact = {
            x: e.touches[0].clientX,
            time: Date.now()
        };
    }, { passive: true });

    document.addEventListener('touchmove', function (e) {
        if (!firstContact)
            return;

        var curX = e.touches[0].clientX;
        var xDiff = curX - firstContact.x,
            tDiff = Date.now() - firstContact.time;

        if (tDiff < 250 && Math.abs(xDiff) >= 150) {
            if (xDiff >= 0 && firstContact.x < Math.min(document.body.clientWidth * 0.25, 300))
                showSidebar();
            else if (xDiff < 0 && curX < 300)
                hideSidebar();

            firstContact = null;
        }
    }, { passive: true });

    // Scroll sidebar to current active section
    var activeSection = sidebar.querySelector(".active");
    if (activeSection) {
        sidebar.scrollTop = activeSection.offsetTop;
    }
})();

(function chapterNavigation() {
    document.addEventListener('keydown', function (e) {
        if (e.altKey || e.ctrlKey || e.metaKey || e.shiftKey) { return; }
        if (window.search && window.search.hasFocus()) { return; }

        switch (e.key) {
            case 'ArrowRight':
                e.preventDefault();
                var nextButton = document.querySelector('.nav-chapters.next');
                if (nextButton) {
                    window.location.href = nextButton.href;
                }
                break;
            case 'ArrowLeft':
                e.preventDefault();
                var previousButton = document.querySelector('.nav-chapters.previous');
                if (previousButton) {
                    window.location.href = previousButton.href;
                }
                break;
        }
    });
})();

(function clipboard() {
    var clipButtons = document.querySelectorAll('.clip-button');

    function hideTooltip(elem) {
        elem.firstChild.innerText = "";
        elem.className = 'fa fa-copy clip-button';
    }

    function showTooltip(elem, msg) {
        elem.firstChild.innerText = msg;
        elem.className = 'fa fa-copy tooltipped';
    }

    var clipboardSnippets = new Clipboard('.clip-button', {
        text: function (trigger) {
            hideTooltip(trigger);
            let playpen = trigger.closest("pre");
            return playpen_text(playpen);
        }
    });

    Array.from(clipButtons).forEach(function (clipButton) {
        clipButton.addEventListener('mouseout', function (e) {
            hideTooltip(e.currentTarget);
        });
    });

    clipboardSnippets.on('success', function (e) {
        e.clearSelection();
        showTooltip(e.trigger, "Copied!");
    });

    clipboardSnippets.on('error', function (e) {
        showTooltip(e.trigger, "Clipboard error!");
    });
})();

(function scrollToTop () {
    var menuTitle = document.querySelector('.menu-title');

    menuTitle.addEventListener('click', function () {
        document.scrollingElement.scrollTo({ top: 0, behavior: 'smooth' });
    });
})();

(function autoHideMenu() {
    var menu = document.getElementById('menu-bar');

    var previousScrollTop = document.scrollingElement.scrollTop;

    document.addEventListener('scroll', function () {
        if (menu.classList.contains('folded') && document.scrollingElement.scrollTop < previousScrollTop) {
            menu.classList.remove('folded');
        } else if (!menu.classList.contains('folded') && document.scrollingElement.scrollTop > previousScrollTop) {
            menu.classList.add('folded');
        }

        if (!menu.classList.contains('bordered') && document.scrollingElement.scrollTop > 0) {
            menu.classList.add('bordered');
        }

        if (menu.classList.contains('bordered') && document.scrollingElement.scrollTop === 0) {
            menu.classList.remove('bordered');
        }

        previousScrollTop = document.scrollingElement.scrollTop;
    }, { passive: true });
})();