Functions.java

/*
 * The MIT License
 *
 * Copyright (c) 2004-2010, Sun Microsystems, Inc., Kohsuke Kawaguchi,
 * Yahoo! Inc., Stephen Connolly, Tom Huybrechts, Alan Harder, Manufacture
 * Francaise des Pneumatiques Michelin, Romain Seguy
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package hudson;

import edu.umd.cs.findbugs.annotations.CheckForNull;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import hudson.cli.CLICommand;
import hudson.console.ConsoleAnnotationDescriptor;
import hudson.console.ConsoleAnnotatorFactory;
import hudson.init.InitMilestone;
import hudson.model.AbstractProject;
import hudson.model.Action;
import hudson.model.Computer;
import hudson.model.Describable;
import hudson.model.Descriptor;
import hudson.model.DescriptorVisibilityFilter;
import hudson.model.Hudson;
import hudson.model.Item;
import hudson.model.ItemGroup;
import hudson.model.Items;
import hudson.model.JDK;
import hudson.model.Job;
import hudson.model.JobPropertyDescriptor;
import hudson.model.ModelObject;
import hudson.model.Node;
import hudson.model.PageDecorator;
import hudson.model.PaneStatusProperties;
import hudson.model.ParameterDefinition;
import hudson.model.ParameterDefinition.ParameterDescriptor;
import hudson.model.PasswordParameterDefinition;
import hudson.model.Run;
import hudson.model.Slave;
import hudson.model.TimeZoneProperty;
import hudson.model.TopLevelItem;
import hudson.model.User;
import hudson.model.View;
import hudson.scm.SCM;
import hudson.scm.SCMDescriptor;
import hudson.search.SearchableModelObject;
import hudson.security.ACL;
import hudson.security.AccessControlled;
import hudson.security.AuthorizationStrategy;
import hudson.security.GlobalSecurityConfiguration;
import hudson.security.Permission;
import hudson.security.SecurityRealm;
import hudson.security.captcha.CaptchaSupport;
import hudson.security.csrf.CrumbIssuer;
import hudson.slaves.Cloud;
import hudson.slaves.ComputerLauncher;
import hudson.slaves.JNLPLauncher;
import hudson.slaves.NodeProperty;
import hudson.slaves.NodePropertyDescriptor;
import hudson.slaves.RetentionStrategy;
import hudson.tasks.BuildStepDescriptor;
import hudson.tasks.BuildWrapper;
import hudson.tasks.BuildWrappers;
import hudson.tasks.Builder;
import hudson.tasks.Publisher;
import hudson.tasks.UserAvatarResolver;
import hudson.util.Area;
import hudson.util.FormValidation.CheckMethod;
import hudson.util.HudsonIsLoading;
import hudson.util.HudsonIsRestarting;
import hudson.util.Iterators;
import hudson.util.RunList;
import hudson.util.Secret;
import hudson.util.jna.GNUCLibrary;
import hudson.views.MyViewsTabBar;
import hudson.views.ViewsTabBar;
import hudson.widgets.RenderOnDemandClosure;
import java.io.File;
import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.Serializable;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.lang.management.LockInfo;
import java.lang.management.ManagementFactory;
import java.lang.management.MonitorInfo;
import java.lang.management.ThreadInfo;
import java.lang.management.ThreadMXBean;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.text.DateFormat;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.ConcurrentModificationException;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.TimeZone;
import java.util.TreeMap;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Predicate;
import java.util.logging.Level;
import java.util.logging.LogManager;
import java.util.logging.LogRecord;
import java.util.logging.Logger;
import java.util.logging.SimpleFormatter;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import jenkins.model.GlobalConfiguration;
import jenkins.model.GlobalConfigurationCategory;
import jenkins.model.Jenkins;
import jenkins.model.ModelObjectWithChildren;
import jenkins.model.ModelObjectWithContextMenu;
import jenkins.model.SimplePageDecorator;
import jenkins.util.SystemProperties;
import org.apache.commons.jelly.JellyContext;
import org.apache.commons.jelly.JellyTagException;
import org.apache.commons.jelly.Script;
import org.apache.commons.jelly.XMLOutput;
import org.apache.commons.jexl.parser.ASTSizeFunction;
import org.apache.commons.jexl.util.Introspector;
import org.apache.commons.lang.StringUtils;
import org.jenkins.ui.icon.Icon;
import org.jenkins.ui.icon.IconSet;
import org.jvnet.tiger_types.Types;
import org.kohsuke.accmod.Restricted;
import org.kohsuke.accmod.restrictions.DoNotUse;
import org.kohsuke.accmod.restrictions.NoExternalUse;
import org.kohsuke.stapler.Ancestor;
import org.kohsuke.stapler.RawHtmlArgument;
import org.kohsuke.stapler.Stapler;
import org.kohsuke.stapler.StaplerRequest;
import org.kohsuke.stapler.StaplerResponse;
import org.springframework.security.access.AccessDeniedException;

/**
 * Utility functions used in views.
 *
 * <p>
 * An instance of this class is created for each request and made accessible
 * from view pages via the variable 'h' (h stands for Hudson.)
 *
 * @author Kohsuke Kawaguchi
 */
@SuppressWarnings("rawtypes")
public class Functions {
    private static final AtomicLong iota = new AtomicLong();
    private static Logger LOGGER = Logger.getLogger(Functions.class.getName());

    public Functions() {
    }

    /**
     * Generates an unique ID.
     */
    public String generateId() {
        return "id" + iota.getAndIncrement();
    }

    public static boolean isModel(Object o) {
        return o instanceof ModelObject;
    }

    public static boolean isModelWithContextMenu(Object o) {
        return o instanceof ModelObjectWithContextMenu;
    }

    public static boolean isModelWithChildren(Object o) {
        return o instanceof ModelObjectWithChildren;
    }

    @Deprecated
    public static boolean isMatrixProject(Object o) {
        return o != null && o.getClass().getName().equals("hudson.matrix.MatrixProject");
    }

    public static String xsDate(Calendar cal) {
        return Util.XS_DATETIME_FORMATTER.format(cal.getTime());
    }

    @Restricted(NoExternalUse.class)
    public static String iso8601DateTime(Date date) {
        return Util.XS_DATETIME_FORMATTER.format(date);
    }

    /**
     * Returns a localized string for the specified date, not including time.
     */
    @Restricted(NoExternalUse.class)
    public static String localDate(Date date) {
        return DateFormat.getDateInstance(DateFormat.SHORT).format(date);
    }

    public static String rfc822Date(Calendar cal) {
        return Util.RFC822_DATETIME_FORMATTER.format(cal.getTime());
    }

    /**
     * Returns a human-readable string describing the time difference between now and the specified date.
     */
    @Restricted(NoExternalUse.class)
    public static String getTimeSpanString(Date date) {
        return Util.getTimeSpanString(Math.abs(date.getTime() - new Date().getTime()));
    }

    /**
     * During Jenkins start-up, before {@link InitMilestone#PLUGINS_STARTED} the extensions lists will be empty
     * and they are not guaranteed to be fully populated until after {@link InitMilestone#EXTENSIONS_AUGMENTED},
     * similarly, during termination after {@link Jenkins#isTerminating()} is set, it is no longer safe to access
     * the extensions lists.
     * If you attempt to access the extensions list from a UI thread while the extensions are being loaded you will
     * hit a big honking great monitor lock that will block until the effective extension list has been determined
     * (as if a plugin fails to start, all of the failed plugin's extensions and any dependent plugins' extensions
     * will have to be evicted from the list of extensions. In practical terms this only affects the
     * "Jenkins is loading" screen, but as that screen uses the generic layouts we provide this utility method
     * so that the generic layouts can avoid iterating extension lists while Jenkins is starting up.
     * If you attempt to access the extensions list from a UI thread while Jenkins is being shut down, the extensions
     * themselves may no longer be in a valid state and could attempt to revive themselves and block termination.
     * In actual terms the termination only affects those views required to render {@link HudsonIsRestarting}'s
     * {@code index.jelly} which is the same set as the {@link HudsonIsLoading} pages so it makes sense to
     * use both checks here.
     *
     * @return {@code true} if the extensions lists have been populated.
     * @since 1.607
     */
    public static boolean isExtensionsAvailable() {
        final Jenkins jenkins = Jenkins.getInstanceOrNull();
        return jenkins != null && jenkins.getInitLevel().compareTo(InitMilestone.EXTENSIONS_AUGMENTED) >= 0
                && !jenkins.isTerminating();
    }

    public static void initPageVariables(JellyContext context) {
        StaplerRequest currentRequest = Stapler.getCurrentRequest();
        currentRequest.getWebApp().getDispatchValidator().allowDispatch(currentRequest, Stapler.getCurrentResponse());
        String rootURL = currentRequest.getContextPath();

        Functions h = new Functions();
        context.setVariable("h", h);


        // The path starts with a "/" character but does not end with a "/" character.
        context.setVariable("rootURL", rootURL);

        /*
            load static resources from the path dedicated to a specific version.
            This "/static/VERSION/abc/def.ghi" path is interpreted by stapler to be
            the same thing as "/abc/def.ghi", but this avoids the stale cache
            problem when the user upgrades to new Jenkins. Stapler also sets a long
            future expiration dates for such static resources.

            see https://wiki.jenkins-ci.org/display/JENKINS/Hyperlinks+in+HTML
         */
        context.setVariable("resURL", rootURL + getResourcePath());
        context.setVariable("imagesURL", rootURL + getResourcePath() + "/images");
        context.setVariable("divBasedFormLayout", true);
        context.setVariable("userAgent", currentRequest.getHeader("User-Agent"));
        IconSet.initPageVariables(context);
    }

    /**
     * Given {@code c=MyList (extends ArrayList<Foo>), base=List}, compute the parameterization of 'base'
     * that's assignable from 'c' (in this case {@code List<Foo>}), and return its n-th type parameter
     * (n=0 would return {@code Foo}).
     *
     * <p>
     * This method is useful for doing type arithmetic.
     *
     * @throws AssertionError
     *      if c' is not parameterized.
     */
    public static <B> Class getTypeParameter(Class<? extends B> c, Class<B> base, int n) {
        Type parameterization = Types.getBaseClass(c, base);
        if (parameterization instanceof ParameterizedType) {
            ParameterizedType pt = (ParameterizedType) parameterization;
            return Types.erasure(Types.getTypeArgument(pt, n));
        } else {
            throw new AssertionError(c + " doesn't properly parameterize " + base);
        }
    }

    public JDK.DescriptorImpl getJDKDescriptor() {
        return Jenkins.get().getDescriptorByType(JDK.DescriptorImpl.class);
    }

    /**
     * Prints the integer as a string that represents difference,
     * like "-5", "+/-0", "+3".
     */
    public static String getDiffString(int i) {
        if (i == 0)    return "±0";
        String s = Integer.toString(i);
        if (i > 0)     return "+" + s;
        else        return s;
    }

    /**
     * {@link #getDiffString(int)} that doesn't show anything for +/-0
     */
    public static String getDiffString2(int i) {
        if (i == 0)    return "";
        String s = Integer.toString(i);
        if (i > 0)     return "+" + s;
        else        return s;
    }

    /**
     * {@link #getDiffString2(int)} that puts the result into prefix and suffix
     * if there's something to print
     */
    public static String getDiffString2(String prefix, int i, String suffix) {
        if (i == 0)    return "";
        String s = Integer.toString(i);
        if (i > 0)     return prefix + "+" + s + suffix;
        else        return prefix + s + suffix;
    }

    /**
     * Adds the proper suffix.
     */
    public static String addSuffix(int n, String singular, String plural) {
        StringBuilder buf = new StringBuilder();
        buf.append(n).append(' ');
        if (n == 1)
            buf.append(singular);
        else
            buf.append(plural);
        return buf.toString();
    }

    public static RunUrl decompose(StaplerRequest req) {
        List<Ancestor> ancestors = req.getAncestors();

        // find the first and last Run instances
        Ancestor f = null, l = null;
        for (Ancestor anc : ancestors) {
            if (anc.getObject() instanceof Run) {
                if (f == null) f = anc;
                l = anc;
            }
        }
        if (l == null) return null;    // there was no Run object

        String head = f.getPrev().getUrl() + '/';
        String base = l.getUrl();

        String reqUri = req.getOriginalRequestURI();
        // Find "rest" or URI by removing N path components.
        // Not using reqUri.substring(f.getUrl().length()) to avoid mismatches due to
        // url-encoding or extra slashes.  Former may occur in Tomcat (despite the spec saying
        // this string is not decoded, Tomcat apparently decodes this string. You see ' '
        // instead of '%20', which is what the browser has sent), latter may occur in some
        // proxy or URL-rewriting setups where extra slashes are inadvertently added.
        String furl = f.getUrl();
        int slashCount = 0;
        // Count components in ancestor URL
        for (int i = furl.indexOf('/'); i >= 0; i = furl.indexOf('/', i + 1)) slashCount++;
        // Remove that many from request URL, ignoring extra slashes
        String rest = reqUri.replaceFirst("(?:/+[^/]*){" + slashCount + "}", "");

        return new RunUrl((Run) f.getObject(), head, base, rest);
    }

    /**
     * If we know the user's screen resolution, return it. Otherwise null.
     * @since 1.213
     */
    public static Area getScreenResolution() {
        Cookie res = Functions.getCookie(Stapler.getCurrentRequest(), "screenResolution");
        if (res != null)
            return Area.parse(res.getValue());
        return null;
    }

    @Restricted(NoExternalUse.class)
    public static boolean useHidingPasswordFields() {
        return SystemProperties.getBoolean(Functions.class.getName() + ".hidingPasswordFields", true);
    }

    /**
     * URL decomposed for easier computation of relevant URLs.
     *
     * <p>
     * The decomposed URL will be of the form:
     * <pre>
     * aaaaaa/524/bbbbb/cccc
     * -head-| N |---rest---
     * ----- base -----|
     * </pre>
     *
     * <p>
     * The head portion is the part of the URL from the {@link Jenkins}
     * object to the first {@link Run} subtype. When "next/prev build"
     * is chosen, this part remains intact.
     *
     * <p>
     * The {@code 524} is the path from {@link Job} to {@link Run}.
     *
     * <p>
     * The {@code bbb} portion is the path after that till the last
     * {@link Run} subtype. The {@code ccc} portion is the part
     * after that.
     */
    public static final class RunUrl {
        private final String head, base, rest;
        private final Run run;


        public RunUrl(Run run, String head, String base, String rest) {
            this.run = run;
            this.head = head;
            this.base = base;
            this.rest = rest;
        }

        public String getBaseUrl() {
            return base;
        }

        /**
         * Returns the same page in the next build.
         */
        public String getNextBuildUrl() {
            return getUrl(run.getNextBuild());
        }

        /**
         * Returns the same page in the previous build.
         */
        public String getPreviousBuildUrl() {
            return getUrl(run.getPreviousBuild());
        }

        private String getUrl(Run n) {
            if (n == null)
                return null;
            else {
                return head + n.getNumber() + rest;
            }
        }
    }

    public static Node.Mode[] getNodeModes() {
        return Node.Mode.values();
    }

    public static String getProjectListString(List<AbstractProject> projects) {
        return Items.toNameList(projects);
    }

    /**
     * @deprecated as of 1.294
     *      JEXL now supports the real ternary operator "x?y:z", so this work around
     *      is no longer necessary.
     */
    @Deprecated
    public static Object ifThenElse(boolean cond, Object thenValue, Object elseValue) {
        return cond ? thenValue : elseValue;
    }

    public static String appendIfNotNull(String text, String suffix, String nullText) {
        return text == null ? nullText : text + suffix;
    }

    public static Map getSystemProperties() {
        return new TreeMap<>(System.getProperties());
    }

    /**
     * Gets the system property indicated by the specified key.
     *
     * Delegates to {@link SystemProperties#getString(String)}.
     */
    @Restricted(DoNotUse.class)
    public static String getSystemProperty(String key) {
        return SystemProperties.getString(key);
    }

    public static Map getEnvVars() {
        return new TreeMap<>(EnvVars.masterEnvVars);
    }

    public static boolean isWindows() {
        return File.pathSeparatorChar == ';';
    }

    public static boolean isGlibcSupported() {
        try {
            GNUCLibrary.LIBC.getpid();
            return true;
        } catch (Throwable t) {
            return false;
        }
    }

    public static List<LogRecord> getLogRecords() {
        return Jenkins.logRecords;
    }

    public static String printLogRecord(LogRecord r) {
        return formatter.format(r);
    }

    @Restricted(NoExternalUse.class)
    public static String[] printLogRecordHtml(LogRecord r, LogRecord prior) {
        String[] oldParts = prior == null ? new String[4] : logRecordPreformat(prior);
        String[] newParts = logRecordPreformat(r);
        for (int i = 0; i < /* not 4 */3; i++) {
            newParts[i] = "<span class='" + (newParts[i].equals(oldParts[i]) ? "logrecord-metadata-old" : "logrecord-metadata-new") + "'>" + newParts[i] + "</span>";
        }
        newParts[3] = Util.xmlEscape(newParts[3]);
        return newParts;
    }
    /**
     * Partially formats a log record.
     * @return date, source, level, message+thrown
     * @see SimpleFormatter#format(LogRecord)
     */

    private static String[] logRecordPreformat(LogRecord r) {
        String source;
        if (r.getSourceClassName() == null) {
            source = r.getLoggerName() == null ? "" : r.getLoggerName();
        } else {
            if (r.getSourceMethodName() == null) {
                source = r.getSourceClassName();
            } else {
                source = r.getSourceClassName() + " " + r.getSourceMethodName();
            }
        }
        String message = new SimpleFormatter().formatMessage(r) + "\n";
        Throwable x = r.getThrown();
        return new String[] {
            String.format("%1$tb %1$td, %1$tY %1$tl:%1$tM:%1$tS %1$Tp", new Date(r.getMillis())),
            source,
            r.getLevel().getLocalizedName(),
            x == null ? message : message + printThrowable(x) + "\n",
        };
    }

    /**
     * Reverses a collection so that it can be easily walked in reverse order.
     * @since 1.525
     */
    public static <T> Iterable<T> reverse(Collection<T> collection) {
        List<T> list = new ArrayList<>(collection);
        Collections.reverse(list);
        return list;
    }

    public static Cookie getCookie(HttpServletRequest req, String name) {
        Cookie[] cookies = req.getCookies();
        if (cookies != null) {
            for (Cookie cookie : cookies) {
                if (cookie.getName().equals(name)) {
                    return cookie;
                }
            }
        }
        return null;
    }

    public static String getCookie(HttpServletRequest req, String name, String defaultValue) {
        Cookie c = getCookie(req, name);
        if (c == null || c.getValue() == null) return defaultValue;
        return c.getValue();
    }

    private static final Pattern ICON_SIZE = Pattern.compile("\\d+x\\d+");

    @Restricted(NoExternalUse.class)
    public static String validateIconSize(String iconSize) throws SecurityException {
        if (!ICON_SIZE.matcher(iconSize).matches()) {
            throw new SecurityException("invalid iconSize");
        }
        return iconSize;
    }

    /**
     * Gets the suffix to use for YUI JavaScript.
     */
    public static String getYuiSuffix() {
        return DEBUG_YUI ? "debug" : "min";
    }

    /**
     * Set to true if you need to use the debug version of YUI.
     */
    @SuppressFBWarnings(value = "MS_SHOULD_BE_FINAL", justification = "for script console")
    public static boolean DEBUG_YUI = SystemProperties.getBoolean("debug.YUI");

    /**
     * Creates a sub map by using the given range (both ends inclusive).
     */
    public static <V> SortedMap<Integer, V> filter(SortedMap<Integer, V> map, String from, String to) {
        if (from == null && to == null)      return map;
        if (to == null)
            return map.headMap(Integer.parseInt(from) - 1);
        if (from == null)
            return map.tailMap(Integer.parseInt(to));

        return map.subMap(Integer.parseInt(to), Integer.parseInt(from) - 1);
    }

    /**
     * Creates a sub map by using the given range (upper end inclusive).
     */
    @Restricted(NoExternalUse.class)
    public static <V> SortedMap<Integer, V> filterExcludingFrom(SortedMap<Integer, V> map, String from, String to) {
        if (from == null && to == null)      return map;
        if (to == null)
            return map.headMap(Integer.parseInt(from));
        if (from == null)
            return map.tailMap(Integer.parseInt(to));

        return map.subMap(Integer.parseInt(to), Integer.parseInt(from));
    }

    private static final SimpleFormatter formatter = new SimpleFormatter();

    /**
     * No longer used.
     *
     * @deprecated auto refresh has been removed
     */
    @Deprecated
    public static void configureAutoRefresh(HttpServletRequest request, HttpServletResponse response, boolean noAutoRefresh) {
        /* feature has been removed */
    }

    @Deprecated
    public static boolean isAutoRefresh(HttpServletRequest request) {
        return false;
    }

    public static boolean isCollapsed(String paneId) {
        return PaneStatusProperties.forCurrentUser().isCollapsed(paneId);
    }

    @Restricted(NoExternalUse.class)
    public static boolean isUserTimeZoneOverride() {
        return TimeZoneProperty.forCurrentUser() != null;
    }

    @CheckForNull
    @Restricted(NoExternalUse.class)
    public static String getUserTimeZone() {
        return TimeZoneProperty.forCurrentUser();
    }

    @Restricted(NoExternalUse.class)
    public static String getUserTimeZonePostfix() {
        if (!isUserTimeZoneOverride()) {
            return "";
        }

        TimeZone tz = TimeZone.getTimeZone(getUserTimeZone());
        return tz.getDisplayName(tz.observesDaylightTime(), TimeZone.SHORT);
    }

    @Restricted(NoExternalUse.class)
    public static long getHourLocalTimezone() {
        // Work around JENKINS-68215. When JENKINS-68215 is resolved, this logic can be moved back to Jelly.
        TimeZone tz = TimeZone.getDefault();
        return TimeUnit.MILLISECONDS.toHours(tz.getRawOffset() + tz.getDSTSavings());
    }

    /**
     * Finds the given object in the ancestor list and returns its URL.
     * This is used to determine the "current" URL assigned to the given object,
     * so that one can compute relative URLs from it.
     */
    public static String getNearestAncestorUrl(StaplerRequest req, Object it) {
        List list = req.getAncestors();
        for (int i = list.size() - 1; i >= 0; i--) {
            Ancestor anc = (Ancestor) list.get(i);
            if (anc.getObject() == it)
                return anc.getUrl();
        }
        return null;
    }

    /**
     * Finds the inner-most {@link SearchableModelObject} in scope.
     */
    public static String getSearchURL() {
        List list = Stapler.getCurrentRequest().getAncestors();
        for (int i = list.size() - 1; i >= 0; i--) {
            Ancestor anc = (Ancestor) list.get(i);
            if (anc.getObject() instanceof SearchableModelObject)
                return anc.getUrl() + "/search/";
        }
        return null;
    }

    public static String appendSpaceIfNotNull(String n) {
        if (n == null) return null;
        else        return n + ' ';
    }

    /**
     * One nbsp per 10 pixels in given size, which may be a plain number or "NxN"
     * (like an iconSize).  Useful in a sortable table heading.
     */
    public static String nbspIndent(String size) {
        int i = size.indexOf('x');
        i = Integer.parseInt(i > 0 ? size.substring(0, i) : size) / 10;
        StringBuilder buf = new StringBuilder(30);
        for (int j = 2; j <= i; j++)
            buf.append("&nbsp;");
        return buf.toString();
    }

    public static String getWin32ErrorMessage(IOException e) {
        return Util.getWin32ErrorMessage(e);
    }

    public static boolean isMultiline(String s) {
        if (s == null)     return false;
        return s.indexOf('\r') >= 0 || s.indexOf('\n') >= 0;
    }

    public static String encode(String s) {
        return Util.encode(s);
    }

    /**
     * Shortcut function for calling {@link URLEncoder#encode(String,String)} (with UTF-8 encoding).<br>
     * Useful for encoding URL query parameters in jelly code (as in {@code "...?param=${h.urlEncode(something)}"}).<br>
     * For convenience in jelly code, it also accepts null parameter, and then returns an empty string.
     *
     * @since 2.200
     */
    public static String urlEncode(String s) {
        if (s == null) {
            return "";
        }
        try {
            return URLEncoder.encode(s, StandardCharsets.UTF_8.name());
        } catch (UnsupportedEncodingException e) {
            throw new Error(e); // impossible
        }
    }

    public static String escape(String s) {
        return Util.escape(s);
    }

    public static String xmlEscape(String s) {
        return Util.xmlEscape(s);
    }

    public static String xmlUnescape(String s) {
        return s.replace("&lt;", "<").replace("&gt;", ">").replace("&amp;", "&");
    }

    public static String htmlAttributeEscape(String text) {
        StringBuilder buf = new StringBuilder(text.length() + 64);
        for (int i = 0; i < text.length(); i++) {
            char ch = text.charAt(i);
            if (ch == '<')
                buf.append("&lt;");
            else
            if (ch == '>')
                buf.append("&gt;");
            else
            if (ch == '&')
                buf.append("&amp;");
            else
            if (ch == '"')
                buf.append("&quot;");
            else
            if (ch == '\'')
                buf.append("&#39;");
            else
                buf.append(ch);
        }
        return buf.toString();
    }

    public static void checkPermission(Permission permission) throws IOException, ServletException {
        checkPermission(Jenkins.get(), permission);
    }

    public static void checkPermission(AccessControlled object, Permission permission) throws IOException, ServletException {
        if (permission != null) {
            object.checkPermission(permission);
        }
    }

    /**
     * This version is so that the 'checkPermission' on {@code layout.jelly}
     * degrades gracefully if "it" is not an {@link AccessControlled} object.
     * Otherwise it will perform no check and that problem is hard to notice.
     */
    public static void checkPermission(Object object, Permission permission) throws IOException, ServletException {
        if (permission == null)
            return;

        if (object instanceof AccessControlled)
            checkPermission((AccessControlled) object, permission);
        else {
            List<Ancestor> ancs = Stapler.getCurrentRequest().getAncestors();
            for (Ancestor anc : Iterators.reverse(ancs)) {
                Object o = anc.getObject();
                if (o instanceof AccessControlled) {
                    checkPermission((AccessControlled) o, permission);
                    return;
                }
            }
            checkPermission(Jenkins.get(), permission);
        }
    }

    /**
     * Returns true if the current user has the given permission.
     *
     * @param permission
     *      If null, returns true. This defaulting is convenient in making the use of this method terse.
     */
    public static boolean hasPermission(Permission permission) throws IOException, ServletException {
        return hasPermission(Jenkins.get(), permission);
    }

    /**
     * This version is so that the 'hasPermission' can degrade gracefully
     * if "it" is not an {@link AccessControlled} object.
     */
    public static boolean hasPermission(Object object, Permission permission) throws IOException, ServletException {
        if (permission == null)
            return true;
        if (object instanceof AccessControlled)
            return ((AccessControlled) object).hasPermission(permission);
        else {
            List<Ancestor> ancs = Stapler.getCurrentRequest().getAncestors();
            for (Ancestor anc : Iterators.reverse(ancs)) {
                Object o = anc.getObject();
                if (o instanceof AccessControlled) {
                    return ((AccessControlled) o).hasPermission(permission);
                }
            }
            return Jenkins.get().hasPermission(permission);
        }
    }

    public static void adminCheck(StaplerRequest req, StaplerResponse rsp, Object required, Permission permission) throws IOException, ServletException {
        // this is legacy --- all views should be eventually converted to
        // the permission based model.
        if (required != null && !Hudson.adminCheck(req, rsp)) {
            // check failed. commit the FORBIDDEN response, then abort.
            rsp.setStatus(HttpServletResponse.SC_FORBIDDEN);
            rsp.getOutputStream().close();
            throw new ServletException("Unauthorized access");
        }

        // make sure the user owns the necessary permission to access this page.
        if (permission != null)
            checkPermission(permission);
    }

    /**
     * Infers the hudson installation URL from the given request.
     */
    public static String inferHudsonURL(StaplerRequest req) {
        String rootUrl = Jenkins.get().getRootUrl();
        if (rootUrl != null)
            // prefer the one explicitly configured, to work with load-balancer, frontend, etc.
            return rootUrl;
        StringBuilder buf = new StringBuilder();
        buf.append(req.getScheme()).append("://");
        buf.append(req.getServerName());
        if (! (req.getScheme().equals("http") && req.getLocalPort() == 80 || req.getScheme().equals("https") && req.getLocalPort() == 443))
            buf.append(':').append(req.getLocalPort());
        buf.append(req.getContextPath()).append('/');
        return buf.toString();
    }

    /**
     * Returns the link to be displayed in the footer of the UI.
     */
    public static String getFooterURL() {
        if (footerURL == null) {
            footerURL = SystemProperties.getString("hudson.footerURL");
            if (StringUtils.isBlank(footerURL)) {
                footerURL = "https://www.jenkins.io/";
            }
        }
        return footerURL;
    }

    private static String footerURL = null;

    public static List<JobPropertyDescriptor> getJobPropertyDescriptors(Class<? extends Job> clazz) {
        return JobPropertyDescriptor.getPropertyDescriptors(clazz);
    }

    public static List<JobPropertyDescriptor> getJobPropertyDescriptors(Job job) {
        return DescriptorVisibilityFilter.apply(job, JobPropertyDescriptor.getPropertyDescriptors(job.getClass()));
    }

    public static List<Descriptor<BuildWrapper>> getBuildWrapperDescriptors(AbstractProject<?, ?> project) {
        return BuildWrappers.getFor(project);
    }

    public static List<Descriptor<SecurityRealm>> getSecurityRealmDescriptors() {
        return SecurityRealm.all();
    }

    public static List<Descriptor<AuthorizationStrategy>> getAuthorizationStrategyDescriptors() {
        return AuthorizationStrategy.all();
    }

    public static List<Descriptor<Builder>> getBuilderDescriptors(AbstractProject<?, ?> project) {
        return BuildStepDescriptor.filter(Builder.all(), project.getClass());
    }

    public static List<Descriptor<Publisher>> getPublisherDescriptors(AbstractProject<?, ?> project) {
        return BuildStepDescriptor.filter(Publisher.all(), project.getClass());
    }

    public static List<SCMDescriptor<?>> getSCMDescriptors(AbstractProject<?, ?> project) {
        return SCM._for((Job) project);
    }

    /**
     * @since 2.12
     * @deprecated replaced by {@link Slave.SlaveDescriptor#computerLauncherDescriptors(Slave)}
     */
    @Deprecated
    @Restricted(DoNotUse.class)
    @RestrictedSince("2.12")
    public static List<Descriptor<ComputerLauncher>> getComputerLauncherDescriptors() {
        return Jenkins.get().getDescriptorList(ComputerLauncher.class);
    }

    /**
     * @since 2.12
     * @deprecated replaced by {@link Slave.SlaveDescriptor#retentionStrategyDescriptors(Slave)}
     */
    @Deprecated
    @Restricted(DoNotUse.class)
    @RestrictedSince("2.12")
    public static List<Descriptor<RetentionStrategy<?>>> getRetentionStrategyDescriptors() {
        return RetentionStrategy.all();
    }

    public static List<ParameterDescriptor> getParameterDescriptors() {
        return ParameterDefinition.all();
    }

    public static List<Descriptor<CaptchaSupport>> getCaptchaSupportDescriptors() {
        return CaptchaSupport.all();
    }

    public static List<Descriptor<ViewsTabBar>> getViewsTabBarDescriptors() {
        return ViewsTabBar.all();
    }

    public static List<Descriptor<MyViewsTabBar>> getMyViewsTabBarDescriptors() {
        return MyViewsTabBar.all();
    }

    /**
     * @deprecated replaced by {@link Slave.SlaveDescriptor#nodePropertyDescriptors(Slave)}
     * @since 2.12
     */
    @Deprecated
    @Restricted(DoNotUse.class)
    @RestrictedSince("2.12")
    public static List<NodePropertyDescriptor> getNodePropertyDescriptors(Class<? extends Node> clazz) {
        List<NodePropertyDescriptor> result = new ArrayList<>();
        Collection<NodePropertyDescriptor> list = (Collection) Jenkins.get().getDescriptorList(NodeProperty.class);
        for (NodePropertyDescriptor npd : list) {
            if (npd.isApplicable(clazz)) {
                result.add(npd);
            }
        }
        return result;
    }

    /**
     * Returns those node properties which can be configured as global node properties.
     *
     * @since 1.520
     */
    public static List<NodePropertyDescriptor> getGlobalNodePropertyDescriptors() {
        List<NodePropertyDescriptor> result = new ArrayList<>();
        Collection<NodePropertyDescriptor> list = (Collection) Jenkins.get().getDescriptorList(NodeProperty.class);
        for (NodePropertyDescriptor npd : list) {
            if (npd.isApplicableAsGlobal()) {
                result.add(npd);
            }
        }
        return result;
    }

    /**
     * Gets all the descriptors sorted by their inheritance tree of {@link Describable}
     * so that descriptors of similar types come nearby.
     *
     * <p>
     * We sort them by {@link Extension#ordinal()} but only for {@link GlobalConfiguration}s,
     * as the value is normally used to compare similar kinds of extensions, and we needed
     * {@link GlobalConfiguration}s to be able to position themselves in a layer above.
     * This however creates some asymmetry between regular {@link Descriptor}s and {@link GlobalConfiguration}s.
     * Perhaps it is better to introduce another annotation element? But then,
     * extensions shouldn't normally concern themselves about ordering too much, and the only reason
     * we needed this for {@link GlobalConfiguration}s are for backward compatibility.
     *
     * @param predicate
     *      Filter the descriptors based on this predicate
     * @since 1.494
     * @deprecated use {@link #getSortedDescriptorsForGlobalConfigByDescriptor(Predicate)}
     */
    @Deprecated
    @Restricted(NoExternalUse.class)
    public static Collection<Descriptor> getSortedDescriptorsForGlobalConfig(com.google.common.base.Predicate<GlobalConfigurationCategory> predicate) {
        ExtensionList<Descriptor> exts = ExtensionList.lookup(Descriptor.class);
        List<Tag> r = new ArrayList<>(exts.size());

        for (ExtensionComponent<Descriptor> c : exts.getComponents()) {
            Descriptor d = c.getInstance();
            if (d.getGlobalConfigPage() == null)  continue;

            if (!Jenkins.get().hasPermission(d.getRequiredGlobalConfigPagePermission())) {
                continue;
            }

            if (predicate.apply(d.getCategory())) {
                r.add(new Tag(c.ordinal(), d));
            }
        }
        Collections.sort(r);

        List<Descriptor> answer = new ArrayList<>(r.size());
        for (Tag d : r) answer.add(d.d);

        return DescriptorVisibilityFilter.apply(Jenkins.get(), answer);
    }

    /**
     * Gets all the descriptors sorted by their inheritance tree of {@link Describable}
     * so that descriptors of similar types come nearby.
     *
     * <p>
     * We sort them by {@link Extension#ordinal()} but only for {@link GlobalConfiguration}s,
     * as the value is normally used to compare similar kinds of extensions, and we needed
     * {@link GlobalConfiguration}s to be able to position themselves in a layer above.
     * This however creates some asymmetry between regular {@link Descriptor}s and {@link GlobalConfiguration}s.
     * Perhaps it is better to introduce another annotation element? But then,
     * extensions shouldn't normally concern themselves about ordering too much, and the only reason
     * we needed this for {@link GlobalConfiguration}s are for backward compatibility.
     *
     * @param predicate
     *      Filter the descriptors based on this predicate
     * @since 2.222
     */
    public static Collection<Descriptor> getSortedDescriptorsForGlobalConfigByDescriptor(Predicate<Descriptor> predicate) {
        ExtensionList<Descriptor> exts = ExtensionList.lookup(Descriptor.class);
        List<Tag> r = new ArrayList<>(exts.size());

        for (ExtensionComponent<Descriptor> c : exts.getComponents()) {
            Descriptor d = c.getInstance();
            if (d.getGlobalConfigPage() == null)  continue;

            if (predicate.test(d)) {
                r.add(new Tag(c.ordinal(), d));
            }
        }
        Collections.sort(r);

        List<Descriptor> answer = new ArrayList<>(r.size());
        for (Tag d : r) answer.add(d.d);

        return DescriptorVisibilityFilter.apply(Jenkins.get(), answer);
    }

    /**
     * Like {@link #getSortedDescriptorsForGlobalConfigByDescriptor(Predicate)} but with a constant truth predicate, to include all descriptors.
     */
    public static Collection<Descriptor> getSortedDescriptorsForGlobalConfigByDescriptor() {
        return getSortedDescriptorsForGlobalConfigByDescriptor(descriptor -> true);
    }

    /**
     * @deprecated This is rather meaningless.
     */
    @Deprecated
    public static Collection<Descriptor> getSortedDescriptorsForGlobalConfigNoSecurity() {
        return getSortedDescriptorsForGlobalConfigByDescriptor(d -> GlobalSecurityConfiguration.FILTER.negate().test(d));
    }

    /**
     * Descriptors in the global configuration form that users with {@link Jenkins#MANAGE} permission can configure.
     *
     * @since 1.506
     */
    public static Collection<Descriptor> getSortedDescriptorsForGlobalConfigUnclassified() {
        return getSortedDescriptorsForGlobalConfigByDescriptor(d -> d.getCategory() instanceof GlobalConfigurationCategory.Unclassified && Jenkins.get().hasPermission(d.getRequiredGlobalConfigPagePermission()));
    }

    /**
     * Descriptors shown in the global configuration form to users with {@link Jenkins#SYSTEM_READ} permission.
     *
     * @since 2.222
     */
    @Restricted(NoExternalUse.class)
    public static Collection<Descriptor> getSortedDescriptorsForGlobalConfigUnclassifiedReadable() {
        return getSortedDescriptorsForGlobalConfigByDescriptor(d -> d.getCategory() instanceof GlobalConfigurationCategory.Unclassified && (
                Jenkins.get().hasPermission(d.getRequiredGlobalConfigPagePermission()) || Jenkins.get().hasPermission(Jenkins.SYSTEM_READ)));
    }

    /**
     * Checks if the current security principal has one of the supplied permissions.
     *
     * @since 2.238
     */
    public static boolean hasAnyPermission(AccessControlled ac, Permission[] permissions) {
        if (permissions == null || permissions.length == 0) {
            return true;
        }

        return ac.hasAnyPermission(permissions);
    }

    /**
     * This version is so that the 'hasAnyPermission'
     * degrades gracefully if "it" is not an {@link AccessControlled} object.
     * Otherwise it will perform no check and that problem is hard to notice.
     *
     * @since 2.238
     */
    public static boolean hasAnyPermission(Object object, Permission[] permissions) throws IOException, ServletException {
        if (permissions == null || permissions.length == 0) {
            return true;
        }

        if (object instanceof AccessControlled)
            return hasAnyPermission((AccessControlled) object, permissions);
        else {
            AccessControlled ac = Stapler.getCurrentRequest().findAncestorObject(AccessControlled.class);
            if (ac != null) {
                return hasAnyPermission(ac, permissions);
            }

            return hasAnyPermission(Jenkins.get(), permissions);
        }
    }

    /**
     * Checks if the current security principal has one of the supplied permissions.
     *
     * @throws AccessDeniedException
     *      if the user doesn't have the permission.
     *
     * @since 2.222
     */
    public static void checkAnyPermission(AccessControlled ac, Permission[] permissions) {
        if (permissions == null || permissions.length == 0) {
            return;
        }

        ac.checkAnyPermission(permissions);
    }

    /**
     * This version is so that the 'checkAnyPermission' on {@code layout.jelly}
     * degrades gracefully if "it" is not an {@link AccessControlled} object.
     * Otherwise it will perform no check and that problem is hard to notice.
     */
    public static void checkAnyPermission(Object object, Permission[] permissions) throws IOException, ServletException {
        if (permissions == null || permissions.length == 0) {
            return;
        }

        if (object instanceof AccessControlled)
            checkAnyPermission((AccessControlled) object, permissions);
        else {
            List<Ancestor> ancs = Stapler.getCurrentRequest().getAncestors();
            for (Ancestor anc : Iterators.reverse(ancs)) {
                Object o = anc.getObject();
                if (o instanceof AccessControlled) {
                    checkAnyPermission((AccessControlled) o, permissions);
                    return;
                }
            }
            checkAnyPermission(Jenkins.get(), permissions);
        }
    }

    private static class Tag implements Comparable<Tag> {
        double ordinal;
        String hierarchy;
        Descriptor d;

        Tag(double ordinal, Descriptor d) {
            this.ordinal = ordinal;
            this.d = d;
            this.hierarchy = buildSuperclassHierarchy(d.clazz, new StringBuilder()).toString();
        }

        private StringBuilder buildSuperclassHierarchy(Class c, StringBuilder buf) {
            Class sc = c.getSuperclass();
            if (sc != null)   buildSuperclassHierarchy(sc, buf).append(':');
            return buf.append(c.getName());
        }

        @Override
        public int compareTo(Tag that) {
            int r = Double.compare(that.ordinal, this.ordinal);
            if (r != 0)   return r; // descending for ordinal by reversing the order for compare
            return this.hierarchy.compareTo(that.hierarchy);
        }
    }
    /**
     * Computes the path to the icon of the given action
     * from the context path.
     */

    public static String getIconFilePath(Action a) {
        String name = a.getIconFileName();
        if (name == null) {
            return null;
        }
        if (name.startsWith("symbol-")) {
            return name;
        }
        if (name.startsWith("/"))
            return name.substring(1);
        else
            return "images/24x24/" + name;
    }

    /**
     * Works like JSTL build-in size(x) function,
     * but handle null gracefully.
     */
    public static int size2(Object o) throws Exception {
        if (o == null) return 0;
        return ASTSizeFunction.sizeOf(o, Introspector.getUberspect());
    }

    /**
     * Computes the relative path from the current page to the given item.
     */
    public static String getRelativeLinkTo(Item p) {
        Map<Object, String> ancestors = new HashMap<>();
        View view = null;

        StaplerRequest request = Stapler.getCurrentRequest();
        for (Ancestor a : request.getAncestors()) {
            ancestors.put(a.getObject(), a.getRelativePath());
            if (a.getObject() instanceof View)
                view = (View) a.getObject();
        }

        String path = ancestors.get(p);
        if (path != null) {
            return normalizeURI(path + '/');
        }

        Item i = p;
        String url = "";
        while (true) {
            ItemGroup ig = i.getParent();
            url = i.getShortUrl() + url;

            if (ig == Jenkins.get() || (view != null && ig == view.getOwner().getItemGroup())) {
                assert i instanceof TopLevelItem;
                if (view != null) {
                    // assume p and the current page belong to the same view, so return a relative path
                    // (even if they did not, View.getItem does not by default verify ownership)
                    return normalizeURI(ancestors.get(view) + '/' + url);
                } else {
                    // otherwise return a path from the root Hudson
                    return normalizeURI(request.getContextPath() + '/' + p.getUrl());
                }
            }

            path = ancestors.get(ig);
            if (path != null) {
                return normalizeURI(path + '/' + url);
            }

            assert ig instanceof Item; // if not, ig must have been the Hudson instance
            i = (Item) ig;
        }
    }

    private static String normalizeURI(String uri) {
        return URI.create(uri).normalize().toString();
    }

    /**
     * Gets all the {@link TopLevelItem}s recursively in the {@link ItemGroup} tree.
     *
     * @since 1.512
     */
    public static List<TopLevelItem> getAllTopLevelItems(ItemGroup root) {
      return root.getAllItems(TopLevelItem.class);
    }

    /**
     * Gets the relative name or display name to the given item from the specified group.
     *
     * @since 1.515
     * @param p the Item we want the relative display name.
     *          If {@code null}, a {@code null} will be returned by the method
     * @param g the ItemGroup used as point of reference for the item.
     *          If the group is not specified, item's path will be used.
     * @param useDisplayName if true, returns a display name, otherwise returns a name
     * @return
     *      String like "foo » bar".
     *      {@code null} if item is null or if one of its parents is not an {@link Item}.
     */
    @Nullable
    public static String getRelativeNameFrom(@CheckForNull Item p, @CheckForNull ItemGroup g, boolean useDisplayName) {
        if (p == null) return null;
        if (g == null) return useDisplayName ? p.getFullDisplayName() : p.getFullName();
        String separationString = useDisplayName ? " » " : "/";

        // first list up all the parents
        Map<ItemGroup, Integer> parents = new HashMap<>();
        int depth = 0;
        while (g != null) {
            parents.put(g, depth++);
            if (g instanceof Item)
                g = ((Item) g).getParent();
            else
                g = null;
        }

        StringBuilder buf = new StringBuilder();
        Item i = p;
        while (true) {
            if (buf.length() > 0) buf.insert(0, separationString);
            buf.insert(0, useDisplayName ? i.getDisplayName() : i.getName());
            ItemGroup gr = i.getParent();

            Integer d = parents.get(gr);
            if (d != null) {
                for (int j = d; j > 0; j--) {
                    buf.insert(0, separationString);
                    buf.insert(0, "..");
                }
                return buf.toString();
            }

            if (gr instanceof Item)
                i = (Item) gr;
            else // Parent is a group, but not an item
                return null;
        }
    }

    /**
     * Gets the name to the given item relative to given group.
     *
     * @since 1.515
     * @param p the Item we want the relative display name
     *          If {@code null}, the method will immediately return {@code null}.
     * @param g the ItemGroup used as point of reference for the item
     * @return
     *      String like "foo/bar".
     *      {@code null} if the item is {@code null} or if one of its parents is not an {@link Item}.
     */
    @Nullable
    public static String getRelativeNameFrom(@CheckForNull Item p, @CheckForNull ItemGroup g) {
        return getRelativeNameFrom(p, g, false);
    }


    /**
     * Gets the relative display name to the given item from the specified group.
     *
     * @since 1.512
     * @param p the Item we want the relative display name.
     *          If {@code null}, the method will immediately return {@code null}.
     * @param g the ItemGroup used as point of reference for the item
     * @return
     *      String like "Foo » Bar".
     *      {@code null} if the item is {@code null} or if one of its parents is not an {@link Item}.
     */
    @Nullable
    public static String getRelativeDisplayNameFrom(@CheckForNull Item p, @CheckForNull ItemGroup g) {
        return getRelativeNameFrom(p, g, true);
    }

    public static Map<Thread, StackTraceElement[]> dumpAllThreads() {
        Map<Thread, StackTraceElement[]> sorted = new TreeMap<>(new ThreadSorter());
        sorted.putAll(Thread.getAllStackTraces());
        return sorted;
    }

    public static ThreadInfo[] getThreadInfos() {
        ThreadMXBean mbean = ManagementFactory.getThreadMXBean();
        return mbean.dumpAllThreads(mbean.isObjectMonitorUsageSupported(), mbean.isSynchronizerUsageSupported());
    }

    public static ThreadGroupMap sortThreadsAndGetGroupMap(ThreadInfo[] list) {
        ThreadGroupMap sorter = new ThreadGroupMap();
        Arrays.sort(list, sorter);
        return sorter;
    }

    // Common code for sorting Threads/ThreadInfos by ThreadGroup
    private static class ThreadSorterBase {
        protected Map<Long, String> map = new HashMap<>();

        ThreadSorterBase() {
            ThreadGroup tg = Thread.currentThread().getThreadGroup();
            while (tg.getParent() != null) tg = tg.getParent();
            Thread[] threads = new Thread[tg.activeCount() * 2];
            int threadsLen = tg.enumerate(threads, true);
            for (int i = 0; i < threadsLen; i++) {
                ThreadGroup group = threads[i].getThreadGroup();
                map.put(threads[i].getId(), group != null ? group.getName() : null);
            }
        }

        protected int compare(long idA, long idB) {
            String tga = map.get(idA), tgb = map.get(idB);
            int result = (tga != null ? -1 : 0) + (tgb != null ? 1 : 0);  // Will be non-zero if only one is null
            if (result == 0 && tga != null)
                result = tga.compareToIgnoreCase(tgb);
            return result;
        }
    }

    public static class ThreadGroupMap extends ThreadSorterBase implements Comparator<ThreadInfo>, Serializable {

        private static final long serialVersionUID = 7803975728695308444L;

        /**
         * @return ThreadGroup name or null if unknown
         */
        public String getThreadGroup(ThreadInfo ti) {
            return map.get(ti.getThreadId());
        }

        @Override
        public int compare(ThreadInfo a, ThreadInfo b) {
            int result = compare(a.getThreadId(), b.getThreadId());
            if (result == 0)
                result = a.getThreadName().compareToIgnoreCase(b.getThreadName());
            return result;
        }
    }

    private static class ThreadSorter extends ThreadSorterBase implements Comparator<Thread>, Serializable {

        private static final long serialVersionUID = 5053631350439192685L;

        @Override
        public int compare(Thread a, Thread b) {
            int result = compare(a.getId(), b.getId());
            if (result == 0)
                result = a.getName().compareToIgnoreCase(b.getName());
            return result;
        }
    }

    /**
     * @deprecated Now always true.
     */
    @Deprecated
    public static boolean isMustangOrAbove() {
        return true;
    }

    // ThreadInfo.toString() truncates the stack trace by first 8, so needed my own version
    public static String dumpThreadInfo(ThreadInfo ti, ThreadGroupMap map) {
        String grp = map.getThreadGroup(ti);
        StringBuilder sb = new StringBuilder("\"" + ti.getThreadName() + "\"" +
                                             " Id=" + ti.getThreadId() + " Group=" +
                                             (grp != null ? grp : "?") + " " +
                                             ti.getThreadState());
        if (ti.getLockName() != null) {
            sb.append(" on " + ti.getLockName());
        }
        if (ti.getLockOwnerName() != null) {
            sb.append(" owned by \"" + ti.getLockOwnerName() +
                      "\" Id=" + ti.getLockOwnerId());
        }
        if (ti.isSuspended()) {
            sb.append(" (suspended)");
        }
        if (ti.isInNative()) {
            sb.append(" (in native)");
        }
        sb.append('\n');
        StackTraceElement[] stackTrace = ti.getStackTrace();
        for (int i = 0; i < stackTrace.length; i++) {
            StackTraceElement ste = stackTrace[i];
            sb.append("\tat ").append(ste);
            sb.append('\n');
            if (i == 0 && ti.getLockInfo() != null) {
                Thread.State ts = ti.getThreadState();
                switch (ts) {
                    case BLOCKED:
                        sb.append("\t-  blocked on ").append(ti.getLockInfo());
                        sb.append('\n');
                        break;
                    case WAITING:
                    case TIMED_WAITING:
                        sb.append("\t-  waiting on ").append(ti.getLockInfo());
                        sb.append('\n');
                        break;
                    default:
                }
            }

            for (MonitorInfo mi : ti.getLockedMonitors()) {
                if (mi.getLockedStackDepth() == i) {
                    sb.append("\t-  locked ").append(mi);
                    sb.append('\n');
                }
            }
       }

       LockInfo[] locks = ti.getLockedSynchronizers();
       if (locks.length > 0) {
           sb.append("\n\tNumber of locked synchronizers = " + locks.length);
           sb.append('\n');
           for (LockInfo li : locks) {
               sb.append("\t- ").append(li);
               sb.append('\n');
           }
       }
       sb.append('\n');
       return sb.toString();
    }

    public static <T> Collection<T> emptyList() {
        return Collections.emptyList();
    }

    public static String jsStringEscape(String s) {
        if (s == null) return null;
        StringBuilder buf = new StringBuilder();
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i);
            switch (ch) {
            case '\'':
                buf.append("\\'");
                break;
            case '\\':
                buf.append("\\\\");
                break;
            case '"':
                buf.append("\\\"");
                break;
            default:
                buf.append(ch);
            }
        }
        return buf.toString();
    }

    /**
     * Converts "abc" to "Abc".
     */
    public static String capitalize(String s) {
        if (s == null || s.length() == 0) return s;
        return Character.toUpperCase(s.charAt(0)) + s.substring(1);
    }

    public static String getVersion() {
        return Jenkins.VERSION;
    }

    /**
     * Resource path prefix.
     */
    public static String getResourcePath() {
        return Jenkins.RESOURCE_PATH;
    }

    public static String getViewResource(Object it, String path) {
        Class clazz = it.getClass();

        if (it instanceof Class)
            clazz = (Class) it;
        if (it instanceof Descriptor)
            clazz = ((Descriptor) it).clazz;

        String buf = Stapler.getCurrentRequest().getContextPath() + Jenkins.VIEW_RESOURCE_PATH + '/' +
                clazz.getName().replace('.', '/').replace('$', '/') +
                '/' + path;
        return buf;
    }

    public static boolean hasView(Object it, String path) throws IOException {
        if (it == null)    return false;
        return Stapler.getCurrentRequest().getView(it, path) != null;
    }

    /**
     * Can be used to check a checkbox by default.
     * Used from views like {@code h.defaultToTrue(scm.useUpdate)}.
     * The expression will evaluate to true if scm is null.
     */
    public static boolean defaultToTrue(Boolean b) {
        if (b == null) return true;
        return b;
    }

    /**
     * If the value exists, return that value. Otherwise return the default value.
     * <p>
     * Starting 1.294, JEXL supports the elvis operator "x?:y" that supersedes this.
     *
     * @since 1.150
     */
    public static <T> T defaulted(T value, T defaultValue) {
        return value != null ? value : defaultValue;
    }

    /**
     * Prints a stack trace from an exception into a readable form.
     * Unlike {@link Throwable#printStackTrace(PrintWriter)}, this implementation follows the suggestion of JDK-6507809
     * to produce a linear trace even when {@link Throwable#getCause} is used.
     * @param t Input {@link Throwable}
     * @return If {@code t} is not null, generally a multiline string ending in a (platform-specific) newline;
     *      otherwise, the method returns a default
     *      &quot;No exception details&quot; string.
     */
    public static @NonNull String printThrowable(@CheckForNull Throwable t) {
        if (t == null) {
            return Messages.Functions_NoExceptionDetails();
        }
        StringBuilder s = new StringBuilder();
        doPrintStackTrace(s, t, null, "", new HashSet<>());
        return s.toString();
    }

    private static void doPrintStackTrace(@NonNull StringBuilder s, @NonNull Throwable t, @CheckForNull Throwable higher, @NonNull String prefix, @NonNull Set<Throwable> encountered) {
        if (!encountered.add(t)) {
            s.append("<cycle to ").append(t).append(">\n");
            return;
        }
        if (Util.isOverridden(Throwable.class, t.getClass(), "printStackTrace", PrintWriter.class)) {
            StringWriter sw = new StringWriter();
            t.printStackTrace(new PrintWriter(sw));
            s.append(sw);
            return;
        }
        Throwable lower = t.getCause();
        if (lower != null) {
            doPrintStackTrace(s, lower, t, prefix, encountered);
        }
        for (Throwable suppressed : t.getSuppressed()) {
            s.append(prefix).append("Also:   ");
            doPrintStackTrace(s, suppressed, t, prefix + "\t", encountered);
        }
        if (lower != null) {
            s.append(prefix).append("Caused: ");
        }
        String summary = t.toString();
        if (lower != null) {
            String suffix = ": " + lower;
            if (summary.endsWith(suffix)) {
                summary = summary.substring(0, summary.length() - suffix.length());
            }
        }
        s.append(summary).append(System.lineSeparator());
        StackTraceElement[] trace = t.getStackTrace();
        int end = trace.length;
        if (higher != null) {
            StackTraceElement[] higherTrace = higher.getStackTrace();
            while (end > 0) {
                int higherEnd = end + higherTrace.length - trace.length;
                if (higherEnd <= 0 || !higherTrace[higherEnd - 1].equals(trace[end - 1])) {
                    break;
                }
                end--;
            }
        }
        for (int i = 0; i < end; i++) {
            s.append(prefix).append("\tat ").append(trace[i]).append(System.lineSeparator());
        }
    }

    /**
     * Like {@link Throwable#printStackTrace(PrintWriter)} but using {@link #printThrowable} format.
     * @param t an exception to print
     * @param pw the log
     * @since 2.43
     */
    public static void printStackTrace(@CheckForNull Throwable t, @NonNull PrintWriter pw) {
        pw.println(printThrowable(t).trim());
    }

    /**
     * Like {@link Throwable#printStackTrace(PrintStream)} but using {@link #printThrowable} format.
     * @param t an exception to print
     * @param ps the log
     * @since 2.43
     */
    public static void printStackTrace(@CheckForNull Throwable t, @NonNull PrintStream ps) {
        ps.println(printThrowable(t).trim());
    }

    /**
     * Counts the number of rows needed for textarea to fit the content.
     * Minimum 5 rows.
     */
    public static int determineRows(String s) {
        if (s == null)     return 5;
        return Math.max(5, LINE_END.split(s).length);
    }

    /**
     * Converts the Hudson build status to CruiseControl build status,
     * which is either Success, Failure, Exception, or Unknown.
     *
     * @deprecated This functionality has been moved to ccxml plugin.
     */
    @Deprecated
    @Restricted(DoNotUse.class)
    @RestrictedSince("2.173")
    public static String toCCStatus(Item i) {
        return "Unknown";
    }

    private static final Pattern LINE_END = Pattern.compile("\r?\n");

    /**
     * Checks if the current user is anonymous.
     */
    public static boolean isAnonymous() {
        return ACL.isAnonymous2(Jenkins.getAuthentication2());
    }

    /**
     * When called from within JEXL expression evaluation,
     * this method returns the current {@link JellyContext} used
     * to evaluate the script.
     *
     * @since 1.164
     */
    public static JellyContext getCurrentJellyContext() {
        JellyContext context = ExpressionFactory2.CURRENT_CONTEXT.get();
        assert context != null;
        return context;
    }

    /**
     * Evaluate a Jelly script and return output as a String.
     *
     * @since 1.267
     */
    public static String runScript(Script script) throws JellyTagException {
        StringWriter out = new StringWriter();
        script.run(getCurrentJellyContext(), XMLOutput.createXMLOutput(out));
        return out.toString();
    }

    /**
     * Returns a sub-list if the given list is bigger than the specified {@code maxSize}.
     * <strong>Warning:</strong> do not call this with a {@link RunList}, or you will break lazy loading!
     */
    public static <T> List<T> subList(List<T> base, int maxSize) {
        if (maxSize < base.size())
            return base.subList(0, maxSize);
        else
            return base;
    }

    /**
     * Combine path components via '/' while handling leading/trailing '/' to avoid duplicates.
     */
    public static String joinPath(String... components) {
        StringBuilder buf = new StringBuilder();
        for (String s : components) {
            if (s.length() == 0)  continue;

            if (buf.length() > 0) {
                if (buf.charAt(buf.length() - 1) != '/')
                    buf.append('/');
                if (s.charAt(0) == '/')   s = s.substring(1);
            }
            buf.append(s);
        }
        return buf.toString();
    }

    /**
     * Computes the hyperlink to actions, to handle the situation when the {@link Action#getUrlName()}
     * returns absolute URL.
     *
     * @return null in case the action should not be presented to the user.
     */
    public static @CheckForNull String getActionUrl(String itUrl, Action action) {
        String urlName = action.getUrlName();
        if (urlName == null)   return null;    // Should not be displayed
        try {
            if (new URI(urlName).isAbsolute()) {
                return urlName;
            }
        } catch (URISyntaxException x) {
            Logger.getLogger(Functions.class.getName()).log(Level.WARNING, "Failed to parse URL for {0}: {1}", new Object[] {action, x});
            return null;
        }
        if (urlName.startsWith("/"))
            return joinPath(Stapler.getCurrentRequest().getContextPath(), urlName);
        else
            // relative URL name
            return joinPath(Stapler.getCurrentRequest().getContextPath() + '/' + itUrl, urlName);
    }

    /**
     * Escapes the character unsafe for e-mail address.
     * See http://en.wikipedia.org/wiki/E-mail_address for the details,
     * but here the vocabulary is even more restricted.
     */
    public static String toEmailSafeString(String projectName) {
        // TODO: escape non-ASCII characters
        StringBuilder buf = new StringBuilder(projectName.length());
        for (int i = 0; i < projectName.length(); i++) {
            char ch = projectName.charAt(i);
            if (('a' <= ch && ch <= 'z')
            || ('A' <= ch && ch <= 'Z')
            || ('0' <= ch && ch <= '9')
            || "-_.".indexOf(ch) >= 0)
                buf.append(ch);
            else
                buf.append('_');    // escape
        }
        return String.valueOf(buf);
    }

    /**
     * Obtains the host name of the Hudson server that clients can use to talk back to.
     * <p>
     * This was primarily used in {@code jenkins-agent.jnlp.jelly} to specify the destination
     * that the agents talk to.
     *
     * @deprecated use {@link JNLPLauncher#getInboundAgentUrl}
     */
    @Deprecated
    public String getServerName() {
        // Try to infer this from the configured root URL.
        // This makes it work correctly when Hudson runs behind a reverse proxy.
        String url = Jenkins.get().getRootUrl();
        try {
            if (url != null) {
                String host = new URL(url).getHost();
                if (host != null)
                    return host;
            }
        } catch (MalformedURLException e) {
            // fall back to HTTP request
        }
        return Stapler.getCurrentRequest().getServerName();
    }

    /**
     * Determines the form validation check URL. See textbox.jelly
     *
     * @deprecated
     *      Use {@link #calcCheckUrl}
     */
    @Deprecated
    public String getCheckUrl(String userDefined, Object descriptor, String field) {
        if (userDefined != null || field == null)   return userDefined;
        if (descriptor instanceof Descriptor) {
            Descriptor d = (Descriptor) descriptor;
            return d.getCheckUrl(field);
        }
        return null;
    }

    /**
     * Determines the parameters that client-side needs for a form validation check. See prepareDatabinding.jelly
     * @since 1.528
     */
    public void calcCheckUrl(Map attributes, String userDefined, Object descriptor, String field) {
        if (userDefined != null || field == null)   return;

        if (descriptor instanceof Descriptor) {
            Descriptor d = (Descriptor) descriptor;
            CheckMethod m = d.getCheckMethod(field);
            attributes.put("checkUrl", m.toStemUrl());
            attributes.put("checkDependsOn", m.getDependsOn());
        }
    }

    /**
     * If the given href link is matching the current page, return true.
     *
     * Used in {@code task.jelly} to decide if the page should be highlighted.
     */
    public boolean hyperlinkMatchesCurrentPage(String href) throws UnsupportedEncodingException {
        String url = Stapler.getCurrentRequest().getRequestURL().toString();
        if (href == null || href.length() <= 1) return ".".equals(href) && url.endsWith("/");
        url = URLDecoder.decode(url, "UTF-8");
        href = URLDecoder.decode(href, "UTF-8");
        if (url.endsWith("/")) url = url.substring(0, url.length() - 1);
        if (href.endsWith("/")) href = href.substring(0, href.length() - 1);

        return url.endsWith(href);
    }

    public <T> List<T> singletonList(T t) {
        return List.of(t);
    }

    /**
     * Gets all the {@link PageDecorator}s.
     */
    public static List<PageDecorator> getPageDecorators() {
        // this method may be called to render start up errors, at which point Hudson doesn't exist yet. see JENKINS-3608
        if (Jenkins.getInstanceOrNull() == null)  return Collections.emptyList();
        return PageDecorator.all();
    }
    /**
     * Gets only one {@link SimplePageDecorator}.
     * @since 2.128
     */

    public static SimplePageDecorator getSimplePageDecorator() {
        return SimplePageDecorator.first();
    }

    public static List<SimplePageDecorator> getSimplePageDecorators() {
        return SimplePageDecorator.all();
    }

    public static List<Descriptor<Cloud>> getCloudDescriptors() {
        return Cloud.all();
    }

    /**
     * Prepend a prefix only when there's the specified body.
     */
    public String prepend(String prefix, String body) {
        if (body != null && body.length() > 0)
            return prefix + body;
        return body;
    }

    public static List<Descriptor<CrumbIssuer>> getCrumbIssuerDescriptors() {
        return CrumbIssuer.all();
    }

    public static String getCrumb(StaplerRequest req) {
        Jenkins h = Jenkins.getInstanceOrNull();
        CrumbIssuer issuer = h != null ? h.getCrumbIssuer() : null;
        return issuer != null ? issuer.getCrumb(req) : "";
    }

    public static String getCrumbRequestField() {
        Jenkins h = Jenkins.getInstanceOrNull();
        CrumbIssuer issuer = h != null ? h.getCrumbIssuer() : null;
        return issuer != null ? issuer.getDescriptor().getCrumbRequestField() : "";
    }

    public static Date getCurrentTime() {
        return new Date();
    }

    public static Locale getCurrentLocale() {
        Locale locale = null;
        StaplerRequest req = Stapler.getCurrentRequest();
        if (req != null)
            locale = req.getLocale();
        if (locale == null)
            locale = Locale.getDefault();
        return locale;
    }

    /**
     * Generate a series of {@code <script>} tags to include {@code script.js}
     * from {@link ConsoleAnnotatorFactory}s and {@link ConsoleAnnotationDescriptor}s.
     */
    public static String generateConsoleAnnotationScriptAndStylesheet() {
        String cp = Stapler.getCurrentRequest().getContextPath() + Jenkins.RESOURCE_PATH;
        StringBuilder buf = new StringBuilder();
        for (ConsoleAnnotatorFactory f : ConsoleAnnotatorFactory.all()) {
            String path = cp + "/extensionList/" + ConsoleAnnotatorFactory.class.getName() + "/" + f.getClass().getName();
            if (f.hasScript())
                buf.append("<script src='").append(path).append("/script.js'></script>");
            if (f.hasStylesheet())
                buf.append("<link rel='stylesheet' type='text/css' href='").append(path).append("/style.css' />");
        }
        for (ConsoleAnnotationDescriptor d : ConsoleAnnotationDescriptor.all()) {
            String path = cp + "/descriptor/" + d.clazz.getName();
            if (d.hasScript())
                buf.append("<script src='").append(path).append("/script.js'></script>");
            if (d.hasStylesheet())
                buf.append("<link rel='stylesheet' type='text/css' href='").append(path).append("/style.css' />");
        }
        return buf.toString();
    }

    /**
     * Work around for bug 6935026.
     */
    public List<String> getLoggerNames() {
        while (true) {
            try {
                List<String> r = new ArrayList<>();
                Enumeration<String> e = LogManager.getLogManager().getLoggerNames();
                while (e.hasMoreElements())
                    r.add(e.nextElement());
                return r;
            } catch (ConcurrentModificationException e) {
                // retry
            }
        }
    }

    /**
     * Used by {@code <f:password/>} so that we send an encrypted value to the client.
     */
    public String getPasswordValue(Object o) {
        if (o == null) {
            return null;
        }

        /*
         Return plain value if it's the default value for PasswordParameterDefinition.
         This needs to work even when the user doesn't have CONFIGURE permission
         */
        if (o.equals(PasswordParameterDefinition.DEFAULT_VALUE)) {
            return o.toString();
        }

        /* Mask from Extended Read */
        StaplerRequest req = Stapler.getCurrentRequest();
        if (o instanceof Secret || Secret.BLANK_NONSECRET_PASSWORD_FIELDS_WITHOUT_ITEM_CONFIGURE) {
            if (req != null) {
                Item item = req.findAncestorObject(Item.class);
                if (item != null && !item.hasPermission(Item.CONFIGURE)) {
                    return "********";
                }
                Computer computer = req.findAncestorObject(Computer.class);
                if (computer != null && !computer.hasPermission(Computer.CONFIGURE)) {
                    return "********";
                }
            }
        }

        /* Return encrypted value if it's a Secret */
        if (o instanceof Secret) {
            return ((Secret) o).getEncryptedValue();
        }

        /* Log a warning if we're in development mode (core or plugin): There's an f:password backed by a non-Secret */
        if (req != null && (Boolean.getBoolean("hudson.hpi.run") || Boolean.getBoolean("hudson.Main.development"))) {
            LOGGER.log(Level.WARNING, () -> "<f:password/> form control in " + getJellyViewsInformationForCurrentRequest() +
                    " is not backed by hudson.util.Secret. Learn more: https://www.jenkins.io/redirect/hudson.util.Secret");
        }

        /* Return plain value if it's not a Secret and the escape hatch is set */
        if (!Secret.AUTO_ENCRYPT_PASSWORD_CONTROL) {
            return o.toString();
        }

        /* Make it a Secret and return its encrypted value */
        return Secret.fromString(o.toString()).getEncryptedValue();
    }

    private String getJellyViewsInformationForCurrentRequest() {
        final Thread thread = Thread.currentThread();
        String threadName = thread.getName();

        // try to simplify based on org.kohsuke.stapler.jelly.JellyViewScript
        // Views are expected to contain a slash and a period, neither as the first char, and the last slash before the first period: Class/view.jelly
        // Nested classes use slashes, so we do not expect period before: Class/Nested/view.jelly
        String views = Arrays.stream(threadName.split(" ")).filter(part -> {
            int slash = part.lastIndexOf("/");
            int firstPeriod = part.indexOf(".");
            return slash > 0 && firstPeriod > 0 && slash < firstPeriod;
        }).collect(Collectors.joining(" "));
        if (StringUtils.isBlank(views)) {
            // fallback to full thread name if there are no apparent views
            return threadName;
        }
        return views;
    }

    public List filterDescriptors(Object context, Iterable descriptors) {
        return DescriptorVisibilityFilter.apply(context, descriptors);
    }

    /**
     * Returns true if we are running unit tests.
     */
    public static boolean getIsUnitTest() {
        return Main.isUnitTest;
    }

    /**
     * Returns {@code true} if the {@link Run#ARTIFACTS} permission is enabled,
     * {@code false} otherwise.
     *
     * <p>When the {@link Run#ARTIFACTS} permission is not turned on using the
     * {@code hudson.security.ArtifactsPermission} system property, this
     * permission must not be considered to be set to {@code false} for every
     * user. It must rather be like if the permission doesn't exist at all
     * (which means that every user has to have an access to the artifacts but
     * the permission can't be configured in the security screen). Got it?</p>
     */
    public static boolean isArtifactsPermissionEnabled() {
        return SystemProperties.getBoolean("hudson.security.ArtifactsPermission");
    }

    /**
     * Returns {@code true} if the {@link Item#WIPEOUT} permission is enabled,
     * {@code false} otherwise.
     *
     * <p>The "Wipe Out Workspace" action available on jobs is controlled by the
     * {@link Item#BUILD} permission. For some specific projects, however, it is
     * not acceptable to let users have this possibility, even it they can
     * trigger builds. As such, when enabling the {@code hudson.security.WipeOutPermission}
     * system property, a new "WipeOut" permission will allow to have greater
     * control on the "Wipe Out Workspace" action.</p>
     */
    public static boolean isWipeOutPermissionEnabled() {
        return SystemProperties.getBoolean("hudson.security.WipeOutPermission");
    }

    public static String createRenderOnDemandProxy(JellyContext context, String attributesToCapture) {
        return Stapler.getCurrentRequest().createJavaScriptProxy(new RenderOnDemandClosure(context, attributesToCapture));
    }

    public static String getCurrentDescriptorByNameUrl() {
        return Descriptor.getCurrentDescriptorByNameUrl();
    }

    public static String setCurrentDescriptorByNameUrl(String value) {
        String o = getCurrentDescriptorByNameUrl();
        Stapler.getCurrentRequest().setAttribute("currentDescriptorByNameUrl", value);

        return o;
    }

    public static void restoreCurrentDescriptorByNameUrl(String old) {
        Stapler.getCurrentRequest().setAttribute("currentDescriptorByNameUrl", old);
    }

    public static List<String> getRequestHeaders(String name) {
        List<String> r = new ArrayList<>();
        Enumeration e = Stapler.getCurrentRequest().getHeaders(name);
        while (e.hasMoreElements()) {
            r.add(e.nextElement().toString());
        }
        return r;
    }

    /**
     * Used for arguments to internationalized expressions to avoid escape
     */
    public static Object rawHtml(Object o) {
        return o == null ? null : new RawHtmlArgument(o);
    }

    public static ArrayList<CLICommand> getCLICommands() {
        ArrayList<CLICommand> all = new ArrayList<>(CLICommand.all());
        all.sort(Comparator.comparing(CLICommand::getName));
        return all;
    }

    /**
     * Returns an avatar image URL for the specified user and preferred image size
     * @param user the user
     * @param avatarSize the preferred size of the avatar image
     * @return a URL string
     * @since 1.433
     */
    public static String getAvatar(User user, String avatarSize) {
        return UserAvatarResolver.resolve(user, avatarSize);
    }

    /**
     * @deprecated as of 1.451
     *      Use {@link #getAvatar}
     */
    @Deprecated
    public String getUserAvatar(User user, String avatarSize) {
        return getAvatar(user, avatarSize);
    }


    /**
     * Returns human readable information about file size
     *
     * @param size file size in bytes
     * @return file size in appropriate unit
     */
    public static String humanReadableByteSize(long size) {
        String measure = "B";
        if (size < 1024) {
            return size + " " + measure;
        }
        double number = size;
        if (number >= 1024) {
            number = number / 1024;
            measure = "KB";
            if (number >= 1024) {
                number = number / 1024;
                measure = "MB";
                if (number >= 1024) {
                    number = number / 1024;
                    measure = "GB";
                }
            }
        }
        DecimalFormat format = new DecimalFormat("#0.00");
        return format.format(number) + " " + measure;
    }

    /**
     * Get a string that can be safely broken to several lines when necessary.
     *
     * This implementation inserts {@code <wbr>} tags into string. It allows browsers
     * to wrap line before any sequence of punctuation characters or anywhere
     * in the middle of prolonged sequences of word characters.
     *
     * @since 1.517
     */
    public static String breakableString(final String plain) {
        if (plain == null) {
            return null;
        }
        return plain.replaceAll("([\\p{Punct}&&[^;]]+\\w)", "<wbr>$1")
                .replaceAll("([^\\p{Punct}\\s-]{20})(?=[^\\p{Punct}\\s-]{10})", "$1<wbr>")
        ;
    }

    /**
     * Advertises the minimum set of HTTP headers that assist programmatic
     * discovery of Jenkins.
     */
    public static void advertiseHeaders(HttpServletResponse rsp) {
        Jenkins j = Jenkins.getInstanceOrNull();
        if (j != null) {
            rsp.setHeader("X-Hudson", "1.395");
            rsp.setHeader("X-Jenkins", Jenkins.VERSION);
            rsp.setHeader("X-Jenkins-Session", Jenkins.SESSION_HASH);
        }
    }

    @Restricted(NoExternalUse.class) // for actions.jelly and ContextMenu.add
    public static boolean isContextMenuVisible(Action a) {
        if (a instanceof ModelObjectWithContextMenu.ContextMenuVisibility) {
            return ((ModelObjectWithContextMenu.ContextMenuVisibility) a).isVisible();
        } else {
            return true;
        }
    }

    @Restricted(NoExternalUse.class)
    public static Icon tryGetIcon(String iconGuess) {
        // Jenkins Symbols don't have metadata so return null
        if (iconGuess == null || iconGuess.startsWith("symbol-")) {
            return null;
        }

        Icon iconMetadata = IconSet.icons.getIconByClassSpec(iconGuess);

        // `iconGuess` must be class names if it contains a whitespace.
        //  It may contains extra css classes unrelated to icons.
        // Filter classes with `icon-` prefix.
        if (iconMetadata == null && iconGuess.contains(" ")) {
            iconMetadata = IconSet.icons.getIconByClassSpec(filterIconNameClasses(iconGuess));
        }

        if (iconMetadata == null) {
            // Icon could be provided as a simple iconFileName e.g. "help.svg"
            iconMetadata = IconSet.icons.getIconByClassSpec(IconSet.toNormalizedIconNameClass(iconGuess) + " icon-md");
        }

        if (iconMetadata == null) {
            // Icon could be provided as an absolute iconFileName e.g. "/plugin/foo/abc.png"
            iconMetadata = IconSet.icons.getIconByUrl(iconGuess);
        }

        return iconMetadata;
    }

    private static @NonNull String filterIconNameClasses(@NonNull String classNames) {
        return Arrays.stream(StringUtils.split(classNames, ' '))
            .filter(className -> className.startsWith("icon-"))
            .collect(Collectors.joining(" "));
    }

    @Restricted(NoExternalUse.class)
    public static String extractPluginNameFromIconSrc(String iconSrc) {
        if (iconSrc == null) {
            return "";
        }

        if (!iconSrc.contains("plugin-")) {
            return "";
        }

        String[] arr = iconSrc.split(" ");
        for (String element : arr) {
            if (element.startsWith("plugin-")) {
                return element.replace("plugin-", "");
            }
        }

        return "";
    }

    @Restricted(NoExternalUse.class)
    public static String tryGetIconPath(String iconGuess, JellyContext context) {
        if (iconGuess == null) {
            return null;
        }

        if (iconGuess.startsWith("symbol-")) {
            return iconGuess;
        }

        StaplerRequest currentRequest = Stapler.getCurrentRequest();
        String rootURL = currentRequest.getContextPath();
        Icon iconMetadata = tryGetIcon(iconGuess);

        String iconSource;
        if (iconMetadata != null) {
            iconSource = IconSet.tryTranslateTangoIconToSymbol(iconMetadata.getClassSpec(), () -> iconMetadata.getQualifiedUrl(context));
        } else {
            iconSource = guessIcon(iconGuess, rootURL);
        }
        return iconSource;
    }

    static String guessIcon(String iconGuess, String rootURL) {
        String iconSource;
        //noinspection HttpUrlsUsage
        if (iconGuess.startsWith("http://") || iconGuess.startsWith("https://")) {
            iconSource = iconGuess;
        } else {
            if (!iconGuess.startsWith("/")) {
                iconGuess = "/" + iconGuess;
            }
            if (iconGuess.startsWith(rootURL)) {
                if ((!rootURL.equals("/images") && !rootURL.equals("/plugin")) || iconGuess.startsWith(rootURL + rootURL)) {
                    iconGuess = iconGuess.substring(rootURL.length());
                }
            }
            iconSource = rootURL + (iconGuess.startsWith("/images/") || iconGuess.startsWith("/plugin/") ? getResourcePath() : "") + iconGuess;
        }
        return iconSource;
    }

    @SuppressFBWarnings(value = "PREDICTABLE_RANDOM", justification = "True randomness isn't necessary for form item IDs")
    @Restricted(NoExternalUse.class)
    public static String generateItemId() {
        return String.valueOf(Math.floor(Math.random() * 3000));
    }
}