com.icesoft.jasper.compiler.TldLocationsCache.java Source code

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/*
 * Copyright 1999,2004 The Apache Software Foundation.
 * 
 * Licensed 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 com.icesoft.jasper.compiler;

import com.icesoft.jasper.JasperException;
import com.icesoft.jasper.xmlparser.ParserUtils;
import com.icesoft.jasper.xmlparser.TreeNode;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.faces.context.ExternalContext;
import java.io.IOException;
import java.io.InputStream;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLConnection;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * A container for all tag libraries that are defined "globally" for the web
 * application.
 * <p/>
 * Tag Libraries can be defined globally in one of two ways: 1. Via <taglib>
 * elements in web.xml: the uri and location of the tag-library are specified in
 * the <taglib> element. 2. Via packaged jar files that contain .tld files
 * within the META-INF directory, or some subdirectory of it. The taglib is
 * 'global' if it has the <uri> element defined.
 * <p/>
 * A mapping between the taglib URI and its associated TaglibraryInfoImpl is
 * maintained in this container. Actually, that's what we'd like to do. However,
 * because of the way the classes TagLibraryInfo and TagInfo have been defined,
 * it is not currently possible to share an instance of TagLibraryInfo across
 * page invocations. A bug has been submitted to the spec lead. In the mean
 * time, all we do is save the 'location' where the TLD associated with a taglib
 * URI can be found.
 * <p/>
 * When a JSP page has a taglib directive, the mappings in this container are
 * first searched (see method getLocation()). If a mapping is found, then the
 * location of the TLD is returned. If no mapping is found, then the uri
 * specified in the taglib directive is to be interpreted as the location for
 * the TLD of this tag library.
 *
 * @author Pierre Delisle
 * @author Jan Luehe
 */

public class TldLocationsCache {

    // Logger
    private static Log log = LogFactory.getLog(TldLocationsCache.class);

    /**
     * The types of URI one may specify for a tag library
     */
    public static final int ABS_URI = 0;
    public static final int ROOT_REL_URI = 1;
    public static final int NOROOT_REL_URI = 2;

    private static final String WEB_XML = "/WEB-INF/web.xml";
    private static final String FILE_PROTOCOL = "file:";
    private static final String JAR_FILE_SUFFIX = ".jar";

    // Names of JARs that are known not to contain any TLDs
    private static HashSet noTldJars;

    /**
     * The mapping of the 'global' tag library URI to the location (resource
     * path) of the TLD associated with that tag library. The location is
     * returned as a String array: [0] The location [1] If the location is a jar
     * file, this is the location of the tld.
     */
    private Hashtable mappings;

    private boolean initialized;
    private ExternalContext ctxt;
    private boolean redeployMode;

    //*********************************************************************
    // Constructor and Initilizations

    /*
     * Initializes the set of JARs that are known not to contain any TLDs
     */
    static {
        noTldJars = new HashSet();
        noTldJars.add("ant.jar");
        noTldJars.add("catalina.jar");
        noTldJars.add("catalina-ant.jar");
        noTldJars.add("catalina-cluster.jar");
        noTldJars.add("catalina-optional.jar");
        noTldJars.add("catalina-i18n-fr.jar");
        noTldJars.add("catalina-i18n-ja.jar");
        noTldJars.add("catalina-i18n-es.jar");
        noTldJars.add("commons-dbcp.jar");
        noTldJars.add("commons-modeler.jar");
        noTldJars.add("commons-logging-api.jar");
        noTldJars.add("commons-beanutils.jar");
        noTldJars.add("commons-fileupload-1.0.jar");
        noTldJars.add("commons-pool.jar");
        noTldJars.add("commons-digester.jar");
        noTldJars.add("commons-logging.jar");
        noTldJars.add("commons-collections.jar");
        noTldJars.add("commons-el.jar");
        noTldJars.add("jakarta-regexp-1.2.jar");
        noTldJars.add("jasper-compiler.jar");
        noTldJars.add("jasper-runtime.jar");
        noTldJars.add("jmx.jar");
        noTldJars.add("jmx-tools.jar");
        noTldJars.add("jsp-api.jar");
        noTldJars.add("jkshm.jar");
        noTldJars.add("jkconfig.jar");
        noTldJars.add("naming-common.jar");
        noTldJars.add("naming-resources.jar");
        noTldJars.add("naming-factory.jar");
        noTldJars.add("naming-java.jar");
        noTldJars.add("servlet-api.jar");
        noTldJars.add("servlets-default.jar");
        noTldJars.add("servlets-invoker.jar");
        noTldJars.add("servlets-common.jar");
        noTldJars.add("servlets-webdav.jar");
        noTldJars.add("tomcat-util.jar");
        noTldJars.add("tomcat-http11.jar");
        noTldJars.add("tomcat-jni.jar");
        noTldJars.add("tomcat-jk.jar");
        noTldJars.add("tomcat-jk2.jar");
        noTldJars.add("tomcat-coyote.jar");
        noTldJars.add("xercesImpl.jar");
        noTldJars.add("xmlParserAPIs.jar");
        noTldJars.add("xml-apis.jar");
        // JARs from J2SE runtime
        noTldJars.add("sunjce_provider.jar");
        noTldJars.add("ldapsec.jar");
        noTldJars.add("localedata.jar");
        noTldJars.add("dnsns.jar");
    }

    public TldLocationsCache(ExternalContext ctxt) {
        this(ctxt, true);
    }

    /**
     * Constructor.
     *
     * @param ctxt         the servlet context of the web application in which
     *                     Jasper is running
     * @param redeployMode if true, then the compiler will allow redeploying a
     *                     tag library from the same jar, at the expense of
     *                     slowing down the server a bit. Note that this may
     *                     only work on JDK 1.3.1_01a and later, because of JDK
     *                     bug 4211817 fixed in this release. If redeployMode is
     *                     false, a faster but less capable mode will be used.
     */
    public TldLocationsCache(ExternalContext ctxt, boolean redeployMode) {
        this.ctxt = ctxt;
        this.redeployMode = redeployMode;
        mappings = new Hashtable();
        initialized = false;
    }

    /**
     * Sets the list of JARs that are known not to contain any TLDs.
     *
     * @param jarNames List of comma-separated names of JAR files that are known
     *                 not to contain any TLDs
     */
    public static void setNoTldJars(String jarNames) {
        if (jarNames != null) {
            noTldJars.clear();
            StringTokenizer tokenizer = new StringTokenizer(jarNames, ",");
            while (tokenizer.hasMoreElements()) {
                noTldJars.add(tokenizer.nextToken());
            }
        }
    }

    /**
     * Gets the 'location' of the TLD associated with the given taglib 'uri'.
     * <p/>
     * Returns null if the uri is not associated with any tag library 'exposed'
     * in the web application. A tag library is 'exposed' either explicitly in
     * web.xml or implicitly via the uri tag in the TLD of a taglib deployed in
     * a jar file (WEB-INF/lib).
     *
     * @param uri The taglib uri
     * @return An array of two Strings: The first element denotes the real path
     *         to the TLD. If the path to the TLD points to a jar file, then the
     *         second element denotes the name of the TLD entry in the jar file.
     *         Returns null if the uri is not associated with any tag library
     *         'exposed' in the web application.
     */
    public String[] getLocation(String uri) throws JasperException {
        if (!initialized) {
            init();
        }
        return (String[]) mappings.get(uri);
    }

    /**
     * Returns the type of a URI: ABS_URI ROOT_REL_URI NOROOT_REL_URI
     */
    public static int uriType(String uri) {
        if (uri.indexOf(':') != -1) {
            return ABS_URI;
        } else if (uri.startsWith("/")) {
            return ROOT_REL_URI;
        } else {
            return NOROOT_REL_URI;
        }
    }

    private void init() throws JasperException {
        if (initialized)
            return;
        try {
            if (log.isDebugEnabled()) {
                log.debug("Initializing ICEfaces TldLocationsCache");
            }
            processWebDotXml();
            scanJars();
            processTldsInFileSystem("/WEB-INF/");
            initialized = true;
        } catch (Exception ex) {
            //           if (log.isDebugEnabled()) {
            //              log.debug(ex.getMessage());
            //           }
            //           ex.printStackTrace();
            throw new JasperException(Localizer.getMessage("jsp.error.internal.tldinit", ex.getMessage()));
        }
    }

    /*
     * Populates taglib map described in web.xml.
     */
    private void processWebDotXml() throws Exception {

        InputStream is = null;

        try {
            // Acquire input stream to web application deployment descriptor
            is = ctxt.getResourceAsStream(WEB_XML);
            if (is == null) {
                if (log.isWarnEnabled()) {
                    log.warn(Localizer.getMessage("jsp.error.internal.filenotfound", WEB_XML));
                }
                return;
            }

            // Parse the web application deployment descriptor
            TreeNode webtld = new ParserUtils().parseXMLDocument(WEB_XML, is);

            // Allow taglib to be an element of the root or jsp-config (JSP2.0)
            TreeNode jspConfig = webtld.findChild("jsp-config");
            if (jspConfig != null) {
                webtld = jspConfig;
            }
            Iterator taglibs = webtld.findChildren("taglib");
            while (taglibs.hasNext()) {

                // Parse the next <taglib> element
                TreeNode taglib = (TreeNode) taglibs.next();
                String tagUri = null;
                String tagLoc = null;
                TreeNode child = taglib.findChild("taglib-uri");
                if (child != null)
                    tagUri = child.getBody();
                child = taglib.findChild("taglib-location");
                if (child != null)
                    tagLoc = child.getBody();

                // Save this location if appropriate
                if (tagLoc == null)
                    continue;
                if (uriType(tagLoc) == NOROOT_REL_URI)
                    tagLoc = "/WEB-INF/" + tagLoc;
                String tagLoc2 = null;
                if (tagLoc.endsWith(JAR_FILE_SUFFIX)) {
                    tagLoc = ctxt.getResource(tagLoc).toString();
                    tagLoc2 = "META-INF/taglib.tld";
                }
                mappings.put(tagUri, new String[] { tagLoc, tagLoc2 });
            }
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    if (log.isDebugEnabled()) {
                        log.debug(e.getLocalizedMessage(), e);
                    }
                }
            }
        }
    }

    /**
     * Scans the given JarURLConnection for TLD files located in META-INF (or a
     * subdirectory of it), adding an implicit map entry to the taglib map for
     * any TLD that has a <uri> element.
     *
     * @param conn   The JarURLConnection to the JAR file to scan
     * @param ignore true if any exceptions raised when processing the given JAR
     *               should be ignored, false otherwise
     */
    private void scanJar(JarURLConnection conn, boolean ignore) throws JasperException {

        JarFile jarFile = null;
        String resourcePath = conn.getJarFileURL().toString();
        try {
            if (redeployMode) {
                conn.setUseCaches(false);
            }
            jarFile = conn.getJarFile();
            Enumeration entries = jarFile.entries();
            while (entries.hasMoreElements()) {
                JarEntry entry = (JarEntry) entries.nextElement();
                String name = entry.getName();
                if (!name.startsWith("META-INF/"))
                    continue;
                if (!name.endsWith(".tld"))
                    continue;
                InputStream stream = jarFile.getInputStream(entry);
                try {
                    String uri = getUriFromTld(resourcePath, stream);
                    // Add implicit map entry only if its uri is not already
                    // present in the map
                    if (uri != null && mappings.get(uri) == null) {
                        mappings.put(uri, new String[] { resourcePath, name });
                    }
                } finally {
                    if (stream != null) {
                        try {
                            stream.close();
                        } catch (IOException e) {
                            if (log.isDebugEnabled()) {
                                log.debug(e.getLocalizedMessage(), e);
                            }
                        }
                    }
                }
            }
        } catch (IOException ex) {
            if (log.isDebugEnabled()) {
                log.debug(ex.getMessage(), ex);
            }
            if (!redeployMode) {
                // if not in redeploy mode, close the jar in case of an error
                if (jarFile != null) {
                    try {
                        jarFile.close();
                    } catch (IOException e) {
                        if (log.isDebugEnabled()) {
                            log.debug(e.getLocalizedMessage(), e);
                        }
                    }
                }
            }
            if (!ignore) {
                throw new JasperException(ex);
            }
        } finally {
            if (redeployMode) {
                // if in redeploy mode, always close the jar
                if (jarFile != null) {
                    try {
                        jarFile.close();
                    } catch (IOException e) {
                        if (log.isDebugEnabled()) {
                            log.debug(e.getLocalizedMessage(), e);
                        }
                    }
                }
            }
        }
    }

    /*
     * Searches the filesystem under /WEB-INF for any TLD files, and adds
     * an implicit map entry to the taglib map for any TLD that has a <uri>
     * element.
     */
    private void processTldsInFileSystem(String startPath) throws Exception {

        Set dirList = ctxt.getResourcePaths(startPath);
        if (dirList != null) {
            Iterator it = dirList.iterator();
            while (it.hasNext()) {
                String path = (String) it.next();
                if (path.endsWith("/")) {
                    processTldsInFileSystem(path);
                }
                if (!path.endsWith(".tld")) {
                    continue;
                }
                InputStream stream = ctxt.getResourceAsStream(path);
                String uri = null;
                try {
                    uri = getUriFromTld(path, stream);
                } finally {
                    if (stream != null) {
                        try {
                            stream.close();
                        } catch (Throwable t) {
                            // do nothing
                        }
                    }
                }
                // Add implicit map entry only if its uri is not already
                // present in the map
                if (uri != null && mappings.get(uri) == null) {
                    mappings.put(uri, new String[] { path, null });
                }
            }
        }
    }

    /*
     * Returns the value of the uri element of the given TLD, or null if the
     * given TLD does not contain any such element.
     */
    private String getUriFromTld(String resourcePath, InputStream in) throws JasperException {
        // Parse the tag library descriptor at the specified resource path
        TreeNode tld = new ParserUtils().parseXMLDocument(resourcePath, in);
        if (tld != null) {
            TreeNode uri = tld.findChild("uri");
            if (uri != null) {
                String body = uri.getBody();
                if (body != null)
                    return body;
            }
        }

        return null;
    }

    /*
     * Scans all JARs accessible to the webapp's classloader and its
     * parent classloaders for TLDs.
     * 
     * The list of JARs always includes the JARs under WEB-INF/lib, as well as
     * all shared JARs in the classloader delegation chain of the webapp's
     * classloader.
     *
     * Considering JARs in the classloader delegation chain constitutes a
     * Tomcat-specific extension to the TLD search
     * order defined in the JSP spec. It allows tag libraries packaged as JAR
     * files to be shared by web applications by simply dropping them in a 
     * location that all web applications have access to (e.g.,
     * <CATALINA_HOME>/common/lib).
     *
     * The set of shared JARs to be scanned for TLDs is narrowed down by
     * the <tt>noTldJars</tt> class variable, which contains the names of JARs
     * that are known not to contain any TLDs.
     */
    private void scanJars() throws Exception {

        ClassLoader webappLoader = Thread.currentThread().getContextClassLoader();
        ClassLoader loader = webappLoader;

        while (loader != null) {
            if (loader instanceof URLClassLoader) {
                URL[] urls = ((URLClassLoader) loader).getURLs();
                if (null != urls) {
                    for (int i = 0; i < urls.length; i++) {
                        URLConnection conn = urls[i].openConnection();
                        if (conn instanceof JarURLConnection) {
                            if (needScanJar(loader, webappLoader,
                                    ((JarURLConnection) conn).getJarFile().getName())) {
                                scanJar((JarURLConnection) conn, true);
                            }
                        } else {
                            String urlStr = urls[i].toString();
                            if (urlStr.startsWith(FILE_PROTOCOL) && urlStr.endsWith(JAR_FILE_SUFFIX)
                                    && needScanJar(loader, webappLoader, urlStr)) {
                                URL jarURL = new URL("jar:" + urlStr + "!/");
                                scanJar((JarURLConnection) jarURL.openConnection(), true);
                            }
                        }
                    }
                }
            }

            loader = loader.getParent();
        }
    }

    /*
     * Determines if the JAR file with the given <tt>jarPath</tt> needs to be
     * scanned for TLDs.
     *
     * @param loader The current classloader in the parent chain
     * @param webappLoader The webapp classloader
     * @param jarPath The JAR file path
     *
     * @return TRUE if the JAR file identified by <tt>jarPath</tt> needs to be
     * scanned for TLDs, FALSE otherwise
     */
    private boolean needScanJar(ClassLoader loader, ClassLoader webappLoader, String jarPath) {
        if (loader == webappLoader) {
            // JARs under WEB-INF/lib must be scanned unconditionally according
            // to the spec.
            return true;
        } else {
            String jarName = jarPath;
            int slash = jarPath.lastIndexOf('/');
            if (slash >= 0) {
                jarName = jarPath.substring(slash + 1);
            }
            return (!noTldJars.contains(jarName));
        }
    }
}