/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.catalina.startup;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.management.ObjectName;

import org.apache.catalina.Container;
import org.apache.catalina.Context;
import org.apache.catalina.DistributedManager;
import org.apache.catalina.Host;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleEvent;
import org.apache.catalina.LifecycleListener;
import org.apache.catalina.Manager;
import org.apache.catalina.core.StandardContext;
import org.apache.catalina.core.StandardHost;
import org.apache.catalina.util.ContextName;
import org.apache.catalina.util.IOTools;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.jakartaee.Migration;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.buf.UriUtil;
import org.apache.tomcat.util.digester.Digester;
import org.apache.tomcat.util.modeler.Registry;
import org.apache.tomcat.util.res.StringManager;

/**
 * Startup event listener for a <b>Host</b> that configures the properties of that Host, and the associated defined
 * contexts.
 */
public class HostConfig implements LifecycleListener {

    private static final Log log = LogFactory.getLog(HostConfig.class);

    /**
     * The string resources for this package.
     */
    protected static final StringManager sm = StringManager.getManager(HostConfig.class);

    /**
     * The resolution, in milliseconds, of file modification times.
     */
    protected static final long FILE_MODIFICATION_RESOLUTION_MS = 1000;


    // ----------------------------------------------------- Instance Variables

    /**
     * The Java class name of the Context implementation we should use.
     */
    protected String contextClass = "org.apache.catalina.core.StandardContext";


    /**
     * The Host we are associated with.
     */
    protected Host host = null;


    /**
     * The JMX ObjectName of this component.
     */
    protected ObjectName oname = null;


    /**
     * Should we deploy XML Context config files packaged with WAR files and directories?
     */
    protected boolean deployXML = false;


    /**
     * Should XML files be copied to $CATALINA_BASE/conf/&lt;engine&gt;/&lt;host&gt; by default when a web application
     * is deployed?
     */
    protected boolean copyXML = false;


    /**
     * Should we unpack WAR files when auto-deploying applications in the <code>appBase</code> directory?
     */
    protected boolean unpackWARs = false;


    /**
     * Map of deployed applications.
     */
    protected final Map<String,DeployedApplication> deployed = new ConcurrentHashMap<>();


    /**
     * Set of applications which are being serviced, and shouldn't be deployed/undeployed/redeployed at the moment.
     */
    private final Set<String> servicedSet = ConcurrentHashMap.newKeySet();

    /**
     * The <code>Digester</code> instance used to parse context descriptors.
     */
    protected Digester digester = createDigester(contextClass);
    private final Object digesterLock = new Object();

    /**
     * The list of Wars in the appBase to be ignored because they are invalid (e.g. contain /../ sequences).
     */
    protected final Set<String> invalidWars = new HashSet<>();

    // ------------------------------------------------------------- Properties


    /**
     * @return the Context implementation class name.
     */
    public String getContextClass() {
        return this.contextClass;
    }


    /**
     * Set the Context implementation class name.
     *
     * @param contextClass The new Context implementation class name.
     */
    public void setContextClass(String contextClass) {

        String oldContextClass = this.contextClass;
        this.contextClass = contextClass;

        if (!oldContextClass.equals(contextClass)) {
            synchronized (digesterLock) {
                digester = createDigester(getContextClass());
            }
        }
    }


    /**
     * @return the deploy XML config file flag for this component.
     */
    public boolean isDeployXML() {
        return this.deployXML;
    }


    /**
     * Set the deploy XML config file flag for this component.
     *
     * @param deployXML The new deploy XML flag
     */
    public void setDeployXML(boolean deployXML) {
        this.deployXML = deployXML;
    }


    /**
     * @return the copy XML config file flag for this component.
     */
    public boolean isCopyXML() {
        return this.copyXML;
    }


    /**
     * Set the copy XML config file flag for this component.
     *
     * @param copyXML The new copy XML flag
     */
    public void setCopyXML(boolean copyXML) {

        this.copyXML = copyXML;

    }


    /**
     * @return the unpack WARs flag.
     */
    public boolean isUnpackWARs() {
        return this.unpackWARs;
    }


    /**
     * Set the unpack WARs flag.
     *
     * @param unpackWARs The new unpack WARs flag
     */
    public void setUnpackWARs(boolean unpackWARs) {
        this.unpackWARs = unpackWARs;
    }


    // --------------------------------------------------------- Public Methods


    /**
     * Process the START event for an associated Host.
     *
     * @param event The lifecycle event that has occurred
     */
    @Override
    public void lifecycleEvent(LifecycleEvent event) {

        // Identify the host we are associated with
        try {
            host = (Host) event.getLifecycle();
            if (host instanceof StandardHost) {
                setCopyXML(((StandardHost) host).isCopyXML());
                setDeployXML(((StandardHost) host).isDeployXML());
                setUnpackWARs(((StandardHost) host).isUnpackWARs());
                setContextClass(((StandardHost) host).getContextClass());
            }
        } catch (ClassCastException e) {
            log.error(sm.getString("hostConfig.cce", event.getLifecycle()), e);
            return;
        }

        // Process the event that has occurred
        switch (event.getType()) {
            case Lifecycle.PERIODIC_EVENT -> check();
            case Lifecycle.BEFORE_START_EVENT -> beforeStart();
            case Lifecycle.START_EVENT -> start();
            case Lifecycle.STOP_EVENT -> stop();
        }
    }


    /**
     * Add a serviced application to the list and indicates if the application was already present in the list.
     *
     * @param name the context name
     *
     * @return {@code true} if the application was not already in the list
     */
    public boolean tryAddServiced(String name) {
        return servicedSet.add(name);
    }


    /**
     * Removed a serviced application from the list.
     *
     * @param name the context name
     */
    public void removeServiced(String name) {
        servicedSet.remove(name);
    }


    /**
     * Get the instant where an application was deployed.
     *
     * @param name the context name
     *
     * @return 0L if no application with that name is deployed, or the instant on which the application was deployed
     */
    public long getDeploymentTime(String name) {
        synchronized (host) {
            DeployedApplication app = deployed.get(name);
            if (app == null) {
                return 0L;
            }

            return app.timestamp;
        }
    }


    /**
     * Has the specified application been deployed? Note applications defined in server.xml will not have been deployed.
     *
     * @param name the context name
     *
     * @return <code>true</code> if the application has been deployed and <code>false</code> if the application has not
     *             been deployed or does not exist
     */
    public boolean isDeployed(String name) {
        return deployed.containsKey(name);
    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Create the digester which will be used to parse context config files.
     *
     * @param contextClassName The class which will be used to create the context instance
     *
     * @return the digester
     */
    protected static Digester createDigester(String contextClassName) {
        Digester digester = new Digester();
        digester.setValidating(false);
        // Add object creation rule
        digester.addObjectCreate("Context", contextClassName, "className");
        // Set the properties on that object (it doesn't matter if extra
        // properties are set)
        digester.addSetProperties("Context");
        return digester;
    }

    protected File returnCanonicalPath(String path) {
        File file = new File(path);
        if (!file.isAbsolute()) {
            file = new File(host.getCatalinaBase(), path);
        }
        try {
            return file.getCanonicalFile();
        } catch (IOException ioe) {
            return file;
        }
    }


    /**
     * Get the name of the configBase. For use with JMX management.
     *
     * @return the config base
     */
    public String getConfigBaseName() {
        return host.getConfigBaseFile().getAbsolutePath();
    }


    /**
     * Deploy applications for any directories or WAR files that are found in our "application root" directory.
     */
    protected void deployApps() {
        // Migrate legacy Java EE apps from legacyAppBase
        migrateLegacyApps();
        File appBase = host.getAppBaseFile();
        File configBase = host.getConfigBaseFile();
        String[] filteredAppPaths = filterAppPaths(appBase.list());
        // Deploy XML descriptors from configBase
        deployDescriptors(configBase, configBase.list());
        // Deploy WARs
        deployWARs(appBase, filteredAppPaths);
        // Deploy expanded folders
        deployDirectories(appBase, filteredAppPaths);
    }


    /**
     * Filter the list of application file paths to remove those that match the regular expression defined by
     * {@link Host#getDeployIgnore()}.
     *
     * @param unfilteredAppPaths The list of application paths to filter
     *
     * @return The filtered list of application paths
     */
    protected String[] filterAppPaths(String[] unfilteredAppPaths) {
        Pattern filter = host.getDeployIgnorePattern();
        if (filter == null || unfilteredAppPaths == null) {
            return unfilteredAppPaths;
        }

        List<String> filteredList = new ArrayList<>();
        Matcher matcher = null;
        for (String appPath : unfilteredAppPaths) {
            if (matcher == null) {
                matcher = filter.matcher(appPath);
            } else {
                matcher.reset(appPath);
            }
            if (matcher.matches()) {
                if (log.isDebugEnabled()) {
                    log.debug(sm.getString("hostConfig.ignorePath", appPath));
                }
            } else {
                filteredList.add(appPath);
            }
        }
        return filteredList.toArray(new String[0]);
    }


    /**
     * Deploy applications for any directories or WAR files that are found in our "application root" directory.
     * <p>
     * Note: It is expected that the caller has successfully added the app to servicedSet before calling this method.
     *
     * @param name The context name which should be deployed
     */
    protected void deployApps(String name) {

        File appBase = host.getAppBaseFile();
        File configBase = host.getConfigBaseFile();
        ContextName cn = new ContextName(name, false);
        String baseName = cn.getBaseName();

        if (deploymentExists(cn.getName())) {
            return;
        }

        // Deploy XML descriptor from configBase
        File xml = new File(configBase, baseName + ".xml");
        if (xml.exists()) {
            deployDescriptor(cn, xml);
            return;
        }
        // Deploy WAR
        File war = new File(appBase, baseName + ".war");
        if (war.exists()) {
            deployWAR(cn, war);
            return;
        }
        // Deploy expanded folder
        File dir = new File(appBase, baseName);
        if (dir.exists()) {
            deployDirectory(cn, dir);
        }
    }


    /**
     * Deploy XML context descriptors.
     *
     * @param configBase The config base
     * @param files      The XML descriptors which should be deployed
     */
    protected void deployDescriptors(File configBase, String[] files) {

        if (files == null) {
            return;
        }

        ExecutorService es = host.getStartStopExecutor();
        List<Future<?>> results = new ArrayList<>();

        for (String file : files) {
            File contextXml = new File(configBase, file);

            if (file.toLowerCase(Locale.ENGLISH).endsWith(".xml")) {
                ContextName cn = new ContextName(file, true);

                if (tryAddServiced(cn.getName())) {
                    try {
                        if (deploymentExists(cn.getName())) {
                            removeServiced(cn.getName());
                            continue;
                        }

                        // DeployDescriptor will call removeServiced
                        results.add(es.submit(new DeployDescriptor(this, cn, contextXml)));
                    } catch (Throwable t) {
                        ExceptionUtils.handleThrowable(t);
                        removeServiced(cn.getName());
                        throw t;
                    }
                }
            }
        }

        for (Future<?> result : results) {
            try {
                result.get();
            } catch (Exception e) {
                log.error(sm.getString("hostConfig.deployDescriptor.threaded.error"), e);
            }
        }
    }


    /**
     * Deploy specified context descriptor.
     * <p>
     * Note: It is expected that the caller has successfully added the app to servicedSet before calling this method.
     *
     * @param cn         The context name
     * @param contextXml The descriptor
     */
    @SuppressWarnings("null") // context is not null
    protected void deployDescriptor(ContextName cn, File contextXml) {

        DeployedApplication deployedApp = new DeployedApplication(cn.getName(), true);

        long startTime = 0;
        // Assume this is a configuration descriptor and deploy it
        if (log.isInfoEnabled()) {
            startTime = System.currentTimeMillis();
            log.info(sm.getString("hostConfig.deployDescriptor", contextXml.getAbsolutePath()));
        }

        Context context = null;
        boolean isExternalWar = false;
        boolean isExternal = false;
        File expandedDocBase;

        try {
            synchronized (digesterLock) {
                try (FileInputStream fis = new FileInputStream(contextXml)) {
                    context = (Context) digester.parse(fis);
                } catch (Exception e) {
                    log.error(sm.getString("hostConfig.deployDescriptor.error", contextXml.getAbsolutePath()), e);
                } finally {
                    digester.reset();
                    if (context == null) {
                        context = new FailedContext();
                    }
                }
            }

            if (context.getPath() != null) {
                log.warn(sm.getString("hostConfig.deployDescriptor.path", context.getPath(),
                        contextXml.getAbsolutePath()));
            }

            Class<?> clazz = Class.forName(host.getConfigClass());
            LifecycleListener listener = (LifecycleListener) clazz.getConstructor().newInstance();
            context.addLifecycleListener(listener);

            context.setConfigFile(contextXml.toURI().toURL());
            context.setName(cn.getName());
            context.setPath(cn.getPath());
            context.setWebappVersion(cn.getVersion());
            // Add the associated docBase to the redeployed list if it's a WAR
            if (context.getDocBase() != null) {
                File docBase = new File(context.getDocBase());
                if (!docBase.isAbsolute()) {
                    docBase = new File(host.getAppBaseFile(), context.getDocBase());
                }
                // If external docBase, register .xml as redeploy first
                if (!docBase.getCanonicalFile().toPath().startsWith(host.getAppBaseFile().toPath())) {
                    isExternal = true;
                    deployedApp.redeployResources.put(contextXml.getAbsolutePath(),
                            Long.valueOf(contextXml.lastModified()));
                    deployedApp.redeployResources.put(docBase.getAbsolutePath(), Long.valueOf(docBase.lastModified()));
                    if (docBase.getAbsolutePath().toLowerCase(Locale.ENGLISH).endsWith(".war")) {
                        isExternalWar = true;
                    }
                    // Check that a WAR or DIR in the appBase is not 'hidden'
                    File war = new File(host.getAppBaseFile(), cn.getBaseName() + ".war");
                    if (war.exists()) {
                        log.warn(sm.getString("hostConfig.deployDescriptor.hiddenWar", contextXml.getAbsolutePath(),
                                war.getAbsolutePath()));
                    }
                    File dir = new File(host.getAppBaseFile(), cn.getBaseName());
                    if (dir.exists()) {
                        log.warn(sm.getString("hostConfig.deployDescriptor.hiddenDir", contextXml.getAbsolutePath(),
                                dir.getAbsolutePath()));
                    }
                } else {
                    log.warn(sm.getString("hostConfig.deployDescriptor.localDocBaseSpecified", docBase));
                    // Ignore specified docBase
                    context.setDocBase(null);
                }
            }

            host.addChild(context);
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            log.error(sm.getString("hostConfig.deployDescriptor.error", contextXml.getAbsolutePath()), t);
        } finally {
            // Get paths for WAR and expanded WAR in appBase

            // default to appBase dir + name
            expandedDocBase = new File(host.getAppBaseFile(), cn.getBaseName());
            if (context != null && context.getDocBase() != null &&
                    !context.getDocBase().toLowerCase(Locale.ENGLISH).endsWith(".war")) {
                // first assume docBase is absolute
                expandedDocBase = new File(context.getDocBase());
                if (!expandedDocBase.isAbsolute()) {
                    // if docBase specified and relative, it must be relative to appBase
                    expandedDocBase = new File(host.getAppBaseFile(), context.getDocBase());
                }
            }

            boolean unpackWAR = unpackWARs;
            if (unpackWAR && context instanceof StandardContext) {
                unpackWAR = ((StandardContext) context).getUnpackWAR();
            }

            // Add the eventual unpacked WAR and all the resources which will be
            // watched inside it
            if (isExternalWar) {
                if (unpackWAR) {
                    deployedApp.redeployResources.put(expandedDocBase.getAbsolutePath(),
                            Long.valueOf(expandedDocBase.lastModified()));
                    addWatchedResources(deployedApp, expandedDocBase.getAbsolutePath(), context);
                } else {
                    addWatchedResources(deployedApp, null, context);
                }
            } else {
                // Find an existing matching war and expanded folder
                if (!isExternal) {
                    File warDocBase = new File(expandedDocBase.getAbsolutePath() + ".war");
                    if (warDocBase.exists()) {
                        deployedApp.redeployResources.put(warDocBase.getAbsolutePath(),
                                Long.valueOf(warDocBase.lastModified()));
                    } else {
                        // Trigger a redeploy if a WAR is added
                        deployedApp.redeployResources.put(warDocBase.getAbsolutePath(), Long.valueOf(0));
                    }
                }
                if (unpackWAR) {
                    deployedApp.redeployResources.put(expandedDocBase.getAbsolutePath(),
                            Long.valueOf(expandedDocBase.lastModified()));
                    addWatchedResources(deployedApp, expandedDocBase.getAbsolutePath(), context);
                } else {
                    addWatchedResources(deployedApp, null, context);
                }
                if (!isExternal) {
                    // For external docBases, the context.xml will have been
                    // added above.
                    deployedApp.redeployResources.put(contextXml.getAbsolutePath(),
                            Long.valueOf(contextXml.lastModified()));
                }
            }
            // Add the global redeploy resources (which are never deleted) at
            // the end so they don't interfere with the deletion process
            addGlobalRedeployResources(deployedApp);
        }

        if (host.findChild(context.getName()) != null) {
            deployed.put(context.getName(), deployedApp);
        }

        if (log.isInfoEnabled()) {
            log.info(sm.getString("hostConfig.deployDescriptor.finished", contextXml.getAbsolutePath(),
                    Long.valueOf(System.currentTimeMillis() - startTime)));
        }
    }


    /**
     * Deploy WAR files.
     *
     * @param appBase The base path for applications
     * @param files   The WARs to deploy
     */
    protected void deployWARs(File appBase, String[] files) {

        if (files == null) {
            return;
        }

        ExecutorService es = host.getStartStopExecutor();
        List<Future<?>> results = new ArrayList<>();

        for (String file : files) {
            if (file.equalsIgnoreCase("META-INF")) {
                continue;
            }
            if (file.equalsIgnoreCase("WEB-INF")) {
                continue;
            }

            File war = new File(appBase, file);
            if (file.toLowerCase(Locale.ENGLISH).endsWith(".war") && war.isFile() && !invalidWars.contains(file)) {
                ContextName cn = new ContextName(file, true);
                if (tryAddServiced(cn.getName())) {
                    try {
                        if (deploymentExists(cn.getName())) {
                            DeployedApplication app = deployed.get(cn.getName());
                            boolean unpackWAR = unpackWARs;
                            if (unpackWAR && host.findChild(cn.getName()) instanceof StandardContext) {
                                unpackWAR = ((StandardContext) host.findChild(cn.getName())).getUnpackWAR();
                            }
                            if (!unpackWAR && app != null) {
                                // Need to check for a directory that should not be
                                // there
                                File dir = new File(appBase, cn.getBaseName());
                                if (dir.exists()) {
                                    if (!app.loggedDirWarning) {
                                        log.warn(sm.getString("hostConfig.deployWar.hiddenDir", dir.getAbsoluteFile(),
                                                war.getAbsoluteFile()));
                                        app.loggedDirWarning = true;
                                    }
                                } else {
                                    app.loggedDirWarning = false;
                                }
                            }
                            removeServiced(cn.getName());
                            continue;
                        }

                        // Check for WARs with /../ /./ or similar sequences in the name
                        if (!validateContextPath(appBase, cn.getBaseName())) {
                            log.error(sm.getString("hostConfig.illegalWarName", file));
                            invalidWars.add(file);
                            removeServiced(cn.getName());
                            continue;
                        }

                        // DeployWAR will call removeServiced
                        results.add(es.submit(new DeployWar(this, cn, war)));
                    } catch (Throwable t) {
                        ExceptionUtils.handleThrowable(t);
                        removeServiced(cn.getName());
                        throw t;
                    }
                }
            }
        }

        for (Future<?> result : results) {
            try {
                result.get();
            } catch (Exception e) {
                log.error(sm.getString("hostConfig.deployWar.threaded.error"), e);
            }
        }
    }


    private boolean validateContextPath(File appBase, String contextPath) {
        // More complicated than the ideal as the canonical path may or may
        // not end with File.separator for a directory

        StringBuilder docBase;
        String canonicalDocBase;

        try {
            String canonicalAppBase = appBase.getCanonicalPath();
            docBase = new StringBuilder(canonicalAppBase);
            if (canonicalAppBase.endsWith(File.separator)) {
                docBase.append(contextPath.substring(1).replace('/', File.separatorChar));
            } else {
                docBase.append(contextPath.replace('/', File.separatorChar));
            }
            // At this point docBase should be canonical but will not end
            // with File.separator

            canonicalDocBase = (new File(docBase.toString())).getCanonicalPath();

            // If the canonicalDocBase ends with File.separator, add one to
            // docBase before they are compared
            if (canonicalDocBase.endsWith(File.separator)) {
                docBase.append(File.separator);
            }
        } catch (IOException ioe) {
            return false;
        }

        // Compare the two. If they are not the same, the contextPath must
        // have /../ like sequences in it
        return canonicalDocBase.contentEquals(docBase);
    }

    /**
     * Deploy packed WAR.
     * <p>
     * Note: It is expected that the caller has successfully added the app to servicedSet before calling this method.
     *
     * @param cn  The context name
     * @param war The WAR file
     */
    protected void deployWAR(ContextName cn, File war) {

        File xml = new File(host.getAppBaseFile(), cn.getBaseName() + "/" + Constants.ApplicationContextXml);

        File warTracker = new File(host.getAppBaseFile(), cn.getBaseName() + Constants.WarTracker);

        boolean xmlInWar = false;
        try (JarFile jar = new JarFile(war)) {
            JarEntry entry = jar.getJarEntry(Constants.ApplicationContextXml);
            if (entry != null) {
                xmlInWar = true;
            }
        } catch (IOException ignore) {
            // Ignore
        }

        // If there is an expanded directory then any xml in that directory
        // should only be used if the directory is not out of date and
        // unpackWARs is true. Note the code below may apply further limits
        boolean useXml =
                xml.exists() && unpackWARs && (!warTracker.exists() || warTracker.lastModified() == war.lastModified());
        // If the xml file exists then expandedDir must exist so no need to
        // test that here

        Context context = null;
        boolean deployThisXML = this.deployXML;

        try {
            if (deployThisXML && useXml && !copyXML) {
                synchronized (digesterLock) {
                    try {
                        context = (Context) digester.parse(xml);
                    } catch (Exception e) {
                        log.error(sm.getString("hostConfig.deployDescriptor.error", war.getAbsolutePath()), e);
                    } finally {
                        digester.reset();
                        if (context == null) {
                            context = new FailedContext();
                        }
                    }
                }
                context.setConfigFile(xml.toURI().toURL());
            } else if (deployThisXML && xmlInWar) {
                synchronized (digesterLock) {
                    try (JarFile jar = new JarFile(war)) {
                        JarEntry entry = jar.getJarEntry(Constants.ApplicationContextXml);
                        try (InputStream istream = jar.getInputStream(entry)) {
                            context = (Context) digester.parse(istream);
                        }
                    } catch (Exception e) {
                        log.error(sm.getString("hostConfig.deployDescriptor.error", war.getAbsolutePath()), e);
                    } finally {
                        digester.reset();
                        if (context == null) {
                            context = new FailedContext();
                        }
                        context.setConfigFile(UriUtil.buildJarUrl(war, Constants.ApplicationContextXml));
                    }
                }
            } else if (!deployThisXML && xmlInWar) {
                // Block deployment as META-INF/context.xml may contain security
                // configuration necessary for a secure deployment.
                log.error(sm.getString("hostConfig.deployDescriptor.blocked", cn.getPath(),
                        Constants.ApplicationContextXml,
                        new File(host.getConfigBaseFile(), cn.getBaseName() + ".xml")));
            } else {
                context = (Context) Class.forName(contextClass).getConstructor().newInstance();
            }
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            log.error(sm.getString("hostConfig.deployWar.error", war.getAbsolutePath()), t);
        } finally {
            if (context == null) {
                context = new FailedContext();
            }
        }

        boolean copyThisXml = false;
        if (deployThisXML) {
            if (host instanceof StandardHost) {
                copyThisXml = ((StandardHost) host).isCopyXML();
            }

            // If Host is using default value Context can override it.
            if (!copyThisXml && context instanceof StandardContext) {
                copyThisXml = ((StandardContext) context).getCopyXML();
            }

            if (xmlInWar && copyThisXml) {
                // Change location of XML file to config base
                xml = new File(host.getConfigBaseFile(), cn.getBaseName() + ".xml");
                try (JarFile jar = new JarFile(war)) {
                    JarEntry entry = jar.getJarEntry(Constants.ApplicationContextXml);
                    try (InputStream istream = jar.getInputStream(entry);
                            OutputStream ostream = new FileOutputStream(xml)) {
                        IOTools.flow(istream, ostream);
                    }
                } catch (IOException ignore) {
                    // Ignore
                }
            }
        }

        DeployedApplication deployedApp =
                new DeployedApplication(cn.getName(), xml.exists() && deployThisXML && copyThisXml);

        long startTime = 0;
        // Deploy the application in this WAR file
        if (log.isInfoEnabled()) {
            startTime = System.currentTimeMillis();
            log.info(sm.getString("hostConfig.deployWar", war.getAbsolutePath()));
        }

        try {
            // Populate redeploy resources with the WAR file
            deployedApp.redeployResources.put(war.getAbsolutePath(), Long.valueOf(war.lastModified()));

            if (deployThisXML && xml.exists() && copyThisXml) {
                deployedApp.redeployResources.put(xml.getAbsolutePath(), Long.valueOf(xml.lastModified()));
            } else {
                // In case an XML file is added to the config base later
                deployedApp.redeployResources.put(
                        (new File(host.getConfigBaseFile(), cn.getBaseName() + ".xml")).getAbsolutePath(),
                        Long.valueOf(0));
            }

            Class<?> clazz = Class.forName(host.getConfigClass());
            LifecycleListener listener = (LifecycleListener) clazz.getConstructor().newInstance();
            context.addLifecycleListener(listener);

            context.setName(cn.getName());
            context.setPath(cn.getPath());
            context.setWebappVersion(cn.getVersion());
            context.setDocBase(cn.getBaseName() + ".war");
            host.addChild(context);
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            log.error(sm.getString("hostConfig.deployWar.error", war.getAbsolutePath()), t);
        } finally {
            // If we're unpacking WARs, the docBase will be mutated after
            // starting the context
            boolean unpackWAR = unpackWARs;
            if (unpackWAR && context instanceof StandardContext) {
                unpackWAR = ((StandardContext) context).getUnpackWAR();
            }
            if (unpackWAR && context.getDocBase() != null) {
                File docBase = new File(host.getAppBaseFile(), cn.getBaseName());
                deployedApp.redeployResources.put(docBase.getAbsolutePath(), Long.valueOf(docBase.lastModified()));
                addWatchedResources(deployedApp, docBase.getAbsolutePath(), context);
                if (deployThisXML && !copyThisXml && (xmlInWar || xml.exists())) {
                    deployedApp.redeployResources.put(xml.getAbsolutePath(), Long.valueOf(xml.lastModified()));
                }
            } else {
                // Passing null for docBase means that no resources will be
                // watched. This will be logged at debug level.
                addWatchedResources(deployedApp, null, context);
            }
            // Add the global redeploy resources (which are never deleted) at
            // the end so they don't interfere with the deletion process
            addGlobalRedeployResources(deployedApp);
        }

        deployed.put(cn.getName(), deployedApp);

        if (log.isInfoEnabled()) {
            log.info(sm.getString("hostConfig.deployWar.finished", war.getAbsolutePath(),
                    Long.valueOf(System.currentTimeMillis() - startTime)));
        }
    }


    /**
     * Deploy exploded webapps.
     *
     * @param appBase The base path for applications
     * @param files   The exploded webapps that should be deployed
     */
    protected void deployDirectories(File appBase, String[] files) {

        if (files == null) {
            return;
        }

        ExecutorService es = host.getStartStopExecutor();
        List<Future<?>> results = new ArrayList<>();

        for (String file : files) {
            if (file.equalsIgnoreCase("META-INF")) {
                continue;
            }
            if (file.equalsIgnoreCase("WEB-INF")) {
                continue;
            }

            File dir = new File(appBase, file);
            if (dir.isDirectory()) {
                ContextName cn = new ContextName(file, false);

                if (tryAddServiced(cn.getName())) {
                    try {
                        if (deploymentExists(cn.getName())) {
                            removeServiced(cn.getName());
                            continue;
                        }

                        // DeployDirectory will call removeServiced
                        results.add(es.submit(new DeployDirectory(this, cn, dir)));
                    } catch (Throwable t) {
                        ExceptionUtils.handleThrowable(t);
                        removeServiced(cn.getName());
                        throw t;
                    }
                }
            }
        }

        for (Future<?> result : results) {
            try {
                result.get();
            } catch (Exception e) {
                log.error(sm.getString("hostConfig.deployDir.threaded.error"), e);
            }
        }
    }


    /**
     * Deploy exploded webapp.
     * <p>
     * Note: It is expected that the caller has successfully added the app to servicedSet before calling this method.
     *
     * @param cn  The context name
     * @param dir The path to the root folder of the webapp
     */
    protected void deployDirectory(ContextName cn, File dir) {

        long startTime = 0;
        // Deploy the application in this directory
        if (log.isInfoEnabled()) {
            startTime = System.currentTimeMillis();
            log.info(sm.getString("hostConfig.deployDir", dir.getAbsolutePath()));
        }

        Context context = null;
        File xml = new File(dir, Constants.ApplicationContextXml);
        File xmlCopy = new File(host.getConfigBaseFile(), cn.getBaseName() + ".xml");

        DeployedApplication deployedApp;
        boolean copyThisXml = isCopyXML();
        boolean deployThisXML = this.deployXML;

        try {
            if (deployThisXML && xml.exists()) {
                synchronized (digesterLock) {
                    try {
                        context = (Context) digester.parse(xml);
                    } catch (Exception e) {
                        log.error(sm.getString("hostConfig.deployDescriptor.error", xml), e);
                        context = new FailedContext();
                    } finally {
                        digester.reset();
                        if (context == null) {
                            context = new FailedContext();
                        }
                    }
                }

                if (!copyThisXml && context instanceof StandardContext) {
                    // Host is using default value. Context may override it.
                    copyThisXml = ((StandardContext) context).getCopyXML();
                }

                if (copyThisXml) {
                    Files.copy(xml.toPath(), xmlCopy.toPath());
                    context.setConfigFile(xmlCopy.toURI().toURL());
                } else {
                    context.setConfigFile(xml.toURI().toURL());
                }
            } else if (!deployThisXML && xml.exists()) {
                // Block deployment as META-INF/context.xml may contain security
                // configuration necessary for a secure deployment.
                log.error(sm.getString("hostConfig.deployDescriptor.blocked", cn.getPath(), xml, xmlCopy));
                context = new FailedContext();
            } else {
                context = (Context) Class.forName(contextClass).getConstructor().newInstance();
            }

            Class<?> clazz = Class.forName(host.getConfigClass());
            LifecycleListener listener = (LifecycleListener) clazz.getConstructor().newInstance();
            context.addLifecycleListener(listener);

            context.setName(cn.getName());
            context.setPath(cn.getPath());
            context.setWebappVersion(cn.getVersion());
            context.setDocBase(cn.getBaseName());
            host.addChild(context);
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            log.error(sm.getString("hostConfig.deployDir.error", dir.getAbsolutePath()), t);
        } finally {
            deployedApp = new DeployedApplication(cn.getName(), xml.exists() && deployThisXML && copyThisXml);

            // Fake re-deploy resource to detect if a WAR is added at a later
            // point
            deployedApp.redeployResources.put(dir.getAbsolutePath() + ".war", Long.valueOf(0));
            deployedApp.redeployResources.put(dir.getAbsolutePath(), Long.valueOf(dir.lastModified()));
            if (deployThisXML && xml.exists()) {
                if (copyThisXml) {
                    deployedApp.redeployResources.put(xmlCopy.getAbsolutePath(), Long.valueOf(xmlCopy.lastModified()));
                } else {
                    deployedApp.redeployResources.put(xml.getAbsolutePath(), Long.valueOf(xml.lastModified()));
                    // Fake re-deploy resource to detect if a context.xml file is
                    // added at a later point
                    deployedApp.redeployResources.put(xmlCopy.getAbsolutePath(), Long.valueOf(0));
                }
            } else {
                // Fake re-deploy resource to detect if a context.xml file is
                // added at a later point
                deployedApp.redeployResources.put(xmlCopy.getAbsolutePath(), Long.valueOf(0));
                if (!xml.exists()) {
                    deployedApp.redeployResources.put(xml.getAbsolutePath(), Long.valueOf(0));
                }
            }
            addWatchedResources(deployedApp, dir.getAbsolutePath(), context);
            // Add the global redeploy resources (which are never deleted) at
            // the end so they don't interfere with the deletion process
            addGlobalRedeployResources(deployedApp);
        }

        deployed.put(cn.getName(), deployedApp);

        if (log.isInfoEnabled()) {
            log.info(sm.getString("hostConfig.deployDir.finished", dir.getAbsolutePath(),
                    Long.valueOf(System.currentTimeMillis() - startTime)));
        }
    }


    protected void migrateLegacyApps() {
        File appBase = host.getAppBaseFile();
        File legacyAppBase = host.getLegacyAppBaseFile();
        if (!legacyAppBase.isDirectory()) {
            return;
        }

        ExecutorService es = host.getStartStopExecutor();
        List<Future<?>> results = new ArrayList<>();

        // Should not be null as we test above if this is a directory
        String[] migrationCandidates = legacyAppBase.list();
        if (migrationCandidates == null) {
            return;
        }
        for (String migrationCandidate : migrationCandidates) {
            File source = new File(legacyAppBase, migrationCandidate);
            File destination = new File(appBase, migrationCandidate);

            ContextName cn;
            if (source.lastModified() > destination.lastModified()) {
                if (source.isFile() && source.getName().toLowerCase(Locale.ENGLISH).endsWith(".war")) {
                    cn = new ContextName(migrationCandidate, true);
                } else if (source.isDirectory()) {
                    cn = new ContextName(migrationCandidate, false);
                } else {
                    continue;
                }

                if (tryAddServiced(cn.getBaseName())) {
                    try {
                        // MigrateApp will call removeServiced
                        results.add(es.submit(new MigrateApp(this, cn, source, destination)));
                    } catch (Throwable t) {
                        ExceptionUtils.handleThrowable(t);
                        removeServiced(cn.getName());
                        throw t;
                    }
                }
            }
        }

        for (Future<?> result : results) {
            try {
                result.get();
            } catch (Exception e) {
                log.error(sm.getString("hostConfig.migrateApp.threaded.error"), e);
            }
        }
    }


    protected void migrateLegacyApp(File source, File destination) {
        File tempNew = null;
        File tempOld;
        try {
            tempNew = File.createTempFile("new", null, host.getLegacyAppBaseFile());
            tempOld = File.createTempFile("old", null, host.getLegacyAppBaseFile());
            // createTempFile is not directly compatible with directories, so cleanup
            Files.delete(tempNew.toPath());
            Files.delete(tempOld.toPath());

            // The use of defaults is deliberate here to avoid having to
            // recreate every configuration option on the host. Better to change
            // the defaults if necessary than to start adding configuration
            // options. Users that need non-default options can convert manually
            // via migration.[sh|bat]
            Migration migration = new Migration();
            migration.setSource(source);
            migration.setDestination(tempNew);
            migration.execute();

            // Use rename
            if (destination.exists()) {
                Files.move(destination.toPath(), tempOld.toPath());
            }
            Files.move(tempNew.toPath(), destination.toPath());
            ExpandWar.delete(tempOld);

        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            log.warn(sm.getString("hostConfig.migrateError"), t);
        } finally {
            if (tempNew != null && tempNew.exists()) {
                ExpandWar.delete(tempNew);
            }
        }
    }


    /**
     * Check if a webapp is already deployed in this host.
     *
     * @param contextName of the context which will be checked
     *
     * @return <code>true</code> if the specified deployment exists
     */
    protected boolean deploymentExists(String contextName) {
        return deployed.containsKey(contextName) || (host.findChild(contextName) != null);
    }


    /**
     * Add watched resources to the specified Context.
     *
     * @param app     HostConfig deployed app
     * @param docBase web app docBase
     * @param context web application context
     */
    protected void addWatchedResources(DeployedApplication app, String docBase, Context context) {
        // FIXME: Feature idea. Add support for patterns (ex: WEB-INF/*,
        // WEB-INF/*.xml), where we would only check if at least one
        // resource is newer than app.timestamp
        File docBaseFile = null;
        if (docBase != null) {
            docBaseFile = new File(docBase);
            if (!docBaseFile.isAbsolute()) {
                docBaseFile = new File(host.getAppBaseFile(), docBase);
            }
        }
        String[] watchedResources = context.findWatchedResources();
        for (String watchedResource : watchedResources) {
            File resource = new File(watchedResource);
            if (!resource.isAbsolute()) {
                if (docBase != null) {
                    resource = new File(docBaseFile, watchedResource);
                } else {
                    if (log.isTraceEnabled()) {
                        log.trace("Ignoring non-existent WatchedResource '" + resource.getAbsolutePath() + "'");
                    }
                    continue;
                }
            }
            if (log.isTraceEnabled()) {
                log.trace("Watching WatchedResource '" + resource.getAbsolutePath() + "'");
            }
            app.reloadResources.put(resource.getAbsolutePath(), Long.valueOf(resource.lastModified()));
        }
    }


    protected void addGlobalRedeployResources(DeployedApplication app) {
        // Redeploy resources processing is hard-coded to never delete this file
        File hostContextXml = new File(getConfigBaseName(), Constants.HostContextXml);
        if (hostContextXml.isFile()) {
            app.redeployResources.put(hostContextXml.getAbsolutePath(), Long.valueOf(hostContextXml.lastModified()));
        }

        // Redeploy resources in CATALINA_BASE/conf are never deleted
        File globalContextXml = returnCanonicalPath(Constants.DefaultContextXml);
        if (globalContextXml.isFile()) {
            app.redeployResources.put(globalContextXml.getAbsolutePath(),
                    Long.valueOf(globalContextXml.lastModified()));
        }
    }


    /**
     * Check resources for redeployment and reloading.
     *
     * @param app                                 The web application to check
     * @param skipFileModificationResolutionCheck When checking files for modification should the check that requires
     *                                                that any file modification must have occurred at least as long ago
     *                                                as the resolution of the file time stamp be skipped
     */
    protected void checkResources(DeployedApplication app, boolean skipFileModificationResolutionCheck) {
        String[] resources = app.redeployResources.keySet().toArray(new String[0]);
        // Offset the current time by the resolution of File.lastModified()
        long currentTimeWithResolutionOffset = System.currentTimeMillis() - FILE_MODIFICATION_RESOLUTION_MS;
        for (int i = 0; i < resources.length; i++) {
            File resource = new File(resources[i]);
            if (log.isTraceEnabled()) {
                log.trace("Checking context[" + app.name + "] redeploy resource " + resource);
            }
            long lastModified = app.redeployResources.get(resources[i]).longValue();
            if (resource.exists() || lastModified == 0) {
                // File.lastModified() has a resolution of 1s (1000ms). The last
                // modified time has to be more than 1000ms ago to ensure that
                // modifications that take place in the same second are not
                // missed. See Bug 57765.
                if (resource.lastModified() != lastModified &&
                        (!host.getAutoDeploy() || resource.lastModified() < currentTimeWithResolutionOffset ||
                                skipFileModificationResolutionCheck)) {
                    if (resource.isDirectory()) {
                        // No action required for modified directory
                        app.redeployResources.put(resources[i], Long.valueOf(resource.lastModified()));
                    } else if (app.hasDescriptor && resource.getName().toLowerCase(Locale.ENGLISH).endsWith(".war")) {
                        // Modified WAR triggers a reload if there is an XML
                        // file present
                        // The only resource that should be deleted is the
                        // expanded WAR (if any)
                        Context context = (Context) host.findChild(app.name);
                        String docBase = context.getDocBase();
                        if (!docBase.toLowerCase(Locale.ENGLISH).endsWith(".war")) {
                            // This is an expanded directory
                            File docBaseFile = new File(docBase);
                            if (!docBaseFile.isAbsolute()) {
                                docBaseFile = new File(host.getAppBaseFile(), docBase);
                            }
                            reload(app, docBaseFile, resource.getAbsolutePath());
                        } else {
                            reload(app, null, null);
                        }
                        // Update times
                        app.redeployResources.put(resources[i], Long.valueOf(resource.lastModified()));
                        app.timestamp = System.currentTimeMillis();
                        boolean unpackWAR = unpackWARs;
                        if (unpackWAR && context instanceof StandardContext) {
                            unpackWAR = ((StandardContext) context).getUnpackWAR();
                        }
                        if (unpackWAR) {
                            addWatchedResources(app, context.getDocBase(), context);
                        } else {
                            addWatchedResources(app, null, context);
                        }
                        return;
                    } else {
                        // Everything else triggers a redeploy
                        // (just need to undeploy here, deploy will follow)
                        undeploy(app);
                        deleteRedeployResources(app, resources, i, false);
                        return;
                    }
                }
            } else {
                // There is a chance the resource was only missing
                // temporarily e.g. renamed during a text editor save
                if (resource.exists() || !resource.getName().toLowerCase(Locale.ENGLISH).endsWith(".war")) {
                    try {
                        Thread.sleep(500);
                    } catch (InterruptedException e1) {
                        // Ignore
                    }
                }
                // Recheck the resource to see if it was really deleted
                if (resource.exists()) {
                    continue;
                }
                // Undeploy application
                undeploy(app);
                deleteRedeployResources(app, resources, i, true);
                return;
            }
        }
        resources = app.reloadResources.keySet().toArray(new String[0]);
        boolean update = false;
        for (String s : resources) {
            File resource = new File(s);
            if (log.isTraceEnabled()) {
                log.trace("Checking context[" + app.name + "] reload resource " + resource);
            }
            long lastModified = app.reloadResources.get(s).longValue();
            // File.lastModified() has a resolution of 1s (1000ms). The last
            // modified time has to be more than 1000ms ago to ensure that
            // modifications that take place in the same second are not
            // missed. See Bug 57765.
            if ((resource.lastModified() != lastModified &&
                    (!host.getAutoDeploy() || resource.lastModified() < currentTimeWithResolutionOffset ||
                            skipFileModificationResolutionCheck)) ||
                    update) {
                if (!update) {
                    // Reload application
                    reload(app, null, null);
                    update = true;
                }
                // Update times. More than one file may have been updated. We
                // don't want to trigger a series of reloads.
                app.reloadResources.put(s, Long.valueOf(resource.lastModified()));
            }
            app.timestamp = System.currentTimeMillis();
        }
    }


    /*
     * Note: If either of fileToRemove and newDocBase are null, both will be ignored.
     */
    private void reload(DeployedApplication app, File fileToRemove, String newDocBase) {
        if (log.isInfoEnabled()) {
            log.info(sm.getString("hostConfig.reload", app.name));
        }
        Context context = (Context) host.findChild(app.name);
        if (context.getState().isAvailable()) {
            if (fileToRemove != null && newDocBase != null) {
                context.addLifecycleListener(new ExpandedDirectoryRemovalListener(fileToRemove, newDocBase));
            }
            // Reload catches and logs exceptions
            context.reload();
        } else {
            // If the context was not started (for example an error
            // in web.xml) we'll still get to try to start
            if (fileToRemove != null && newDocBase != null) {
                ExpandWar.delete(fileToRemove);
                context.setDocBase(newDocBase);
            }
            try {
                context.start();
            } catch (Exception e) {
                log.error(sm.getString("hostConfig.context.restart", app.name), e);
            }
        }
    }


    private void undeploy(DeployedApplication app) {
        if (log.isInfoEnabled()) {
            log.info(sm.getString("hostConfig.undeploy", app.name));
        }
        Container context = host.findChild(app.name);
        try {
            host.removeChild(context);
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            log.warn(sm.getString("hostConfig.context.remove", app.name), t);
        }
        deployed.remove(app.name);
    }


    private void deleteRedeployResources(DeployedApplication app, String[] resources, int i,
            boolean deleteReloadResources) {

        // Delete other redeploy resources
        for (int j = i + 1; j < resources.length; j++) {
            File current = new File(resources[j]);
            // Never delete per host context.xml defaults
            if (Constants.HostContextXml.equals(current.getName())) {
                continue;
            }
            // Only delete resources in the appBase or the
            // host's configBase
            if (isDeletableResource(app, current)) {
                if (log.isDebugEnabled()) {
                    log.debug(sm.getString("hostConfig.delete", current));
                }
                ExpandWar.delete(current);
            }
        }

        // Delete reload resources (to remove any remaining .xml descriptor)
        if (deleteReloadResources) {
            String[] resources2 = app.reloadResources.keySet().toArray(new String[0]);
            for (String s : resources2) {
                File current = new File(s);
                // Never delete per host context.xml defaults
                if (Constants.HostContextXml.equals(current.getName())) {
                    continue;
                }
                // Only delete resources in the appBase or the host's
                // configBase
                if (isDeletableResource(app, current)) {
                    if (log.isDebugEnabled()) {
                        log.debug(sm.getString("hostConfig.delete", current));
                    }
                    ExpandWar.delete(current);
                }
            }
        }
    }


    /*
     * Delete any resource that would trigger the automatic deployment code to re-deploy the application. This means
     * deleting:
     *
     * - any resource located in the appBase
     *
     * - any deployment descriptor located under the configBase
     *
     * - symlinks in the appBase or configBase for either of the above
     */
    private boolean isDeletableResource(DeployedApplication app, File resource) {
        // The resource may be a file, a directory or a symlink to a file or directory.

        // Check that the resource is absolute. This should always be the case.
        if (!resource.isAbsolute()) {
            log.warn(sm.getString("hostConfig.resourceNotAbsolute", app.name, resource));
            return false;
        }

        // Determine where the resource is located
        String canonicalLocation;
        try {
            canonicalLocation = resource.getParentFile().getCanonicalPath();
        } catch (IOException ioe) {
            log.warn(sm.getString("hostConfig.canonicalizing", resource.getParentFile(), app.name), ioe);
            return false;
        }

        String canonicalAppBase;
        try {
            canonicalAppBase = host.getAppBaseFile().getCanonicalPath();
        } catch (IOException ioe) {
            log.warn(sm.getString("hostConfig.canonicalizing", host.getAppBaseFile(), app.name), ioe);
            return false;
        }

        if (canonicalLocation.equals(canonicalAppBase)) {
            // Resource is located in the appBase so it may be deleted
            return true;
        }

        String canonicalConfigBase;
        try {
            canonicalConfigBase = host.getConfigBaseFile().getCanonicalPath();
        } catch (IOException ioe) {
            log.warn(sm.getString("hostConfig.canonicalizing", host.getConfigBaseFile(), app.name), ioe);
            return false;
        }

        // Resource is a xml file in the configBase so it may be deleted
        return canonicalLocation.equals(canonicalConfigBase) && resource.getName().endsWith(".xml");
        // All other resources should not be deleted
    }


    public void beforeStart() {
        if (host.getCreateDirs()) {
            File[] dirs = new File[] { host.getAppBaseFile(), host.getConfigBaseFile() };
            for (File dir : dirs) {
                if (!dir.mkdirs() && !dir.isDirectory()) {
                    log.error(sm.getString("hostConfig.createDirs", dir));
                }
            }
        }
    }


    /**
     * Process a "start" event for this Host.
     */
    public void start() {

        if (log.isTraceEnabled()) {
            log.trace(sm.getString("hostConfig.start"));
        }

        try {
            ObjectName hostON = host.getObjectName();
            oname = new ObjectName(hostON.getDomain() + ":type=Deployer,host=" + host.getName());
            Registry.getRegistry(null).registerComponent(this, oname, this.getClass().getName());
        } catch (Exception e) {
            log.warn(sm.getString("hostConfig.jmx.register", oname), e);
        }

        if (!host.getAppBaseFile().isDirectory()) {
            log.error(sm.getString("hostConfig.appBase", host.getName(), host.getAppBaseFile().getPath()));
            host.setDeployOnStartup(false);
            host.setAutoDeploy(false);
        }

        if (host.getDeployOnStartup()) {
            deployApps();
        }
    }


    /**
     * Process a "stop" event for this Host.
     */
    public void stop() {

        if (log.isTraceEnabled()) {
            log.trace(sm.getString("hostConfig.stop"));
        }

        if (oname != null) {
            try {
                Registry.getRegistry(null).unregisterComponent(oname);
            } catch (Exception e) {
                log.warn(sm.getString("hostConfig.jmx.unregister", oname), e);
            }
        }
        oname = null;
    }


    /**
     * Check status of all webapps.
     */
    protected void check() {

        if (host.getAutoDeploy()) {
            // Check for resources modification to trigger redeployment
            DeployedApplication[] apps = deployed.values().toArray(new DeployedApplication[0]);
            for (DeployedApplication app : apps) {
                if (tryAddServiced(app.name)) {
                    try {
                        checkResources(app, false);
                    } finally {
                        removeServiced(app.name);
                    }
                }
            }

            // Check for old versions of applications that can now be undeployed
            if (host.getUndeployOldVersions()) {
                checkUndeploy();
            }

            // Hotdeploy applications
            deployApps();
        }
    }


    /**
     * Check status of a specific web application and reload, redeploy or deploy it as necessary. This method is for use
     * with functionality such as management web applications that upload new/updated web applications and need to
     * trigger the appropriate action to deploy them. This method assumes that any uploading/updating has been completed
     * before this method is called. Any action taken as a result of the checks will complete before this method
     * returns.
     *
     * @param name The name of the web application to check
     */
    public void check(String name) {
        synchronized (host) {
            if (!host.getState().isAvailable()) {
                return;
            }
            if (tryAddServiced(name)) {
                try {
                    DeployedApplication app = deployed.get(name);
                    if (app != null) {
                        checkResources(app, true);
                    }
                    deployApps(name);
                } finally {
                    removeServiced(name);
                }
            }
        }
    }

    /**
     * Check for old versions of applications using parallel deployment that are now unused (have no active sessions)
     * and undeploy any that are found.
     */
    public void checkUndeploy() {
        synchronized (host) {
            if (deployed.size() < 2) {
                return;
            }

            // Need ordered set of names
            SortedSet<String> sortedAppNames = new TreeSet<>(deployed.keySet());

            Iterator<String> iter = sortedAppNames.iterator();

            ContextName previous = new ContextName(iter.next(), false);
            do {
                ContextName current = new ContextName(iter.next(), false);

                if (current.getPath().equals(previous.getPath())) {
                    // Current and previous are same path - current will always
                    // be a later version
                    Context previousContext = (Context) host.findChild(previous.getName());
                    Context currentContext = (Context) host.findChild(current.getName());
                    if (previousContext != null && currentContext != null && currentContext.getState().isAvailable() &&
                            tryAddServiced(previous.getName())) {
                        try {
                            Manager manager = previousContext.getManager();
                            if (manager != null) {
                                int sessionCount;
                                if (manager instanceof DistributedManager) {
                                    sessionCount = ((DistributedManager) manager).getActiveSessionsFull();
                                } else {
                                    sessionCount = manager.getActiveSessions();
                                }
                                if (sessionCount == 0) {
                                    if (log.isInfoEnabled()) {
                                        log.info(sm.getString("hostConfig.undeployVersion", previous.getName()));
                                    }
                                    DeployedApplication app = deployed.get(previous.getName());
                                    String[] resources = app.redeployResources.keySet().toArray(new String[0]);
                                    // Version is unused - undeploy it completely
                                    // The -1 is a 'trick' to ensure all redeploy
                                    // resources are removed
                                    undeploy(app);
                                    deleteRedeployResources(app, resources, -1, true);
                                }
                            }
                        } finally {
                            removeServiced(previous.getName());
                        }
                    }
                }
                previous = current;
            } while (iter.hasNext());
        }
    }

    /**
     * Add a new Context to be managed by us. Entry point for the admin webapp, and other JMX Context controllers.
     *
     * @param context The context instance
     */
    public void manageApp(Context context) {

        String contextName = context.getName();

        if (deployed.containsKey(contextName)) {
            return;
        }

        DeployedApplication deployedApp = new DeployedApplication(contextName, false);

        // Add the associated docBase to the redeployed list if it's a WAR
        boolean isWar = false;
        if (context.getDocBase() != null) {
            File docBase = new File(context.getDocBase());
            if (!docBase.isAbsolute()) {
                docBase = new File(host.getAppBaseFile(), context.getDocBase());
            }
            deployedApp.redeployResources.put(docBase.getAbsolutePath(), Long.valueOf(docBase.lastModified()));
            if (docBase.getAbsolutePath().toLowerCase(Locale.ENGLISH).endsWith(".war")) {
                isWar = true;
            }
        }
        host.addChild(context);
        // Add the eventual unpacked WAR and all the resources which will be
        // watched inside it
        boolean unpackWAR = unpackWARs;
        if (unpackWAR && context instanceof StandardContext) {
            unpackWAR = ((StandardContext) context).getUnpackWAR();
        }
        if (isWar && unpackWAR) {
            File docBase = new File(host.getAppBaseFile(), context.getBaseName());
            deployedApp.redeployResources.put(docBase.getAbsolutePath(), Long.valueOf(docBase.lastModified()));
            addWatchedResources(deployedApp, docBase.getAbsolutePath(), context);
        } else {
            addWatchedResources(deployedApp, null, context);
        }
        deployed.put(contextName, deployedApp);
    }

    /**
     * Remove a webapp from our control. Entry point for the admin webapp, and other JMX Context controllers.
     * <p>
     * Note: It is expected that the caller has successfully added the app to servicedSet before calling this method.
     *
     * @param contextName The context name
     */
    public void unmanageApp(String contextName) {
        deployed.remove(contextName);
        host.removeChild(host.findChild(contextName));
    }

    // ----------------------------------------------------- Instance Variables


    /**
     * This class represents the state of a deployed application, as well as the monitored resources.
     */
    protected static class DeployedApplication {
        public DeployedApplication(String name, boolean hasDescriptor) {
            this.name = name;
            this.hasDescriptor = hasDescriptor;
        }

        /**
         * Application context path. The assertion is that (host.getChild(name) != null).
         */
        public final String name;

        /**
         * Does this application have a context.xml descriptor file on the host's configBase?
         */
        public final boolean hasDescriptor;

        /**
         * Any modification of the specified (static) resources will cause a redeployment of the application. If any of
         * the specified resources is removed, the application will be undeployed. Typically, this will contain
         * resources like the context.xml file, a compressed WAR path. The value is the last modification time.
         */
        public final LinkedHashMap<String,Long> redeployResources = new LinkedHashMap<>();

        /**
         * Any modification of the specified (static) resources will cause a reload of the application. This will
         * typically contain resources such as the web.xml of a webapp, but can be configured to contain additional
         * descriptors. The value is the last modification time.
         */
        public final HashMap<String,Long> reloadResources = new HashMap<>();

        /**
         * Instant where the application was last put in service.
         */
        public long timestamp = System.currentTimeMillis();

        /**
         * In some circumstances, such as when unpackWARs is true, a directory may be added to the appBase that is
         * ignored. This flag indicates that the user has been warned so that the warning is not logged on every run of
         * the auto deployer.
         */
        public boolean loggedDirWarning = false;
    }

    private record DeployDescriptor(HostConfig config, ContextName cn, File descriptor) implements Runnable {
        @Override
        public void run() {
            try {
                config.deployDescriptor(cn, descriptor);
            } finally {
                config.removeServiced(cn.getName());
            }
        }
    }

    private record DeployWar(HostConfig config, ContextName cn, File war) implements Runnable {
        @Override
        public void run() {
            try {
                config.deployWAR(cn, war);
            } finally {
                config.removeServiced(cn.getName());
            }
        }
    }

    private record DeployDirectory(HostConfig config, ContextName cn, File dir) implements Runnable {
        @Override
        public void run() {
            try {
                config.deployDirectory(cn, dir);
            } finally {
                config.removeServiced(cn.getName());
            }
        }
    }


    private record MigrateApp(HostConfig config, ContextName cn, File source, File destination) implements Runnable {
        @Override
        public void run() {
            try {
                config.migrateLegacyApp(source, destination);
            } finally {
                config.removeServiced(cn.getName());
            }
        }
    }


    /*
     * The purpose of this class is to provide a way for HostConfig to get a Context to delete an expanded WAR after the
     * Context stops. This is to resolve this issue described in Bug 57772. The alternative solutions require either
     * duplicating a lot of the Context.reload() code in HostConfig or adding a new reload(boolean) method to Context
     * that allows the caller to optionally delete any expanded WAR.
     *
     * The LifecycleListener approach offers greater flexibility and enables the behaviour to be changed / extended /
     * removed in future without changing the Context API.
     */
    private record ExpandedDirectoryRemovalListener(File toDelete, String newDocBase) implements LifecycleListener {
        @Override
        public void lifecycleEvent(LifecycleEvent event) {
            if (Lifecycle.AFTER_STOP_EVENT.equals(event.getType())) {
                // The context has stopped.
                Context context = (Context) event.getLifecycle();

                // Remove the old expanded WAR.
                ExpandWar.delete(toDelete);

                // Reset the docBase to trigger re-expansion of the WAR.
                context.setDocBase(newDocBase);

                // Remove this listener from the Context else it will run every
                // time the Context is stopped.
                context.removeLifecycleListener(this);
            }
        }
    }
}