org.apache.tools.ant.AntClassLoader Maven / Gradle / Ivy
/*
* 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.tools.ant;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.file.Files;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.security.cert.Certificate;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
import java.util.Vector;
import java.util.jar.Attributes;
import java.util.jar.Attributes.Name;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import org.apache.tools.ant.launch.Locator;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.util.CollectionUtils;
import org.apache.tools.ant.util.FileUtils;
import org.apache.tools.ant.util.JavaEnvUtils;
import org.apache.tools.ant.util.LoaderUtils;
import org.apache.tools.ant.util.StringUtils;
import org.apache.tools.ant.util.VectorSet;
import org.apache.tools.zip.ZipLong;
/**
* Used to load classes within ant with a different classpath from
* that used to start ant. Note that it is possible to force a class
* into this loader even when that class is on the system classpath by
* using the forceLoadClass method. Any subsequent classes loaded by that
* class will then use this loader rather than the system class loader.
*
*
* Note that this classloader has a feature to allow loading
* in reverse order and for "isolation".
* Due to the fact that a number of
* methods in java.lang.ClassLoader are final (at least
* in java 1.4 getResources) this means that the
* class has to fake the given parent.
*
*
*/
public class AntClassLoader extends ClassLoader implements SubBuildListener, Closeable {
private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();
static {
registerAsParallelCapable();
}
/**
* An enumeration of all resources of a given name found within the
* classpath of this class loader. This enumeration is used by the
* ClassLoader.findResources method, which is in
* turn used by the ClassLoader.getResources method.
*
* @see AntClassLoader#findResources(String)
* @see java.lang.ClassLoader#getResources(String)
*/
private class ResourceEnumeration implements Enumeration {
/**
* The name of the resource being searched for.
*/
private final String resourceName;
/**
* The index of the next classpath element to search.
*/
private int pathElementsIndex;
/**
* The URL of the next resource to return in the enumeration. If this
* field is null then the enumeration has been completed,
* i.e., there are no more elements to return.
*/
private URL nextResource;
/**
* Constructs a new enumeration of resources of the given name found
* within this class loader's classpath.
*
* @param name the name of the resource to search for.
*/
ResourceEnumeration(final String name) {
this.resourceName = name;
this.pathElementsIndex = 0;
findNextResource();
}
/**
* Indicates whether there are more elements in the enumeration to
* return.
*
* @return true if there are more elements in the
* enumeration; false otherwise.
*/
public boolean hasMoreElements() {
return (this.nextResource != null);
}
/**
* Returns the next resource in the enumeration.
*
* @return the next resource in the enumeration
*/
public URL nextElement() {
final URL ret = this.nextResource;
if (ret == null) {
throw new NoSuchElementException();
}
findNextResource();
return ret;
}
/**
* Locates the next resource of the correct name in the classpath and
* sets nextResource to the URL of that resource. If no
* more resources can be found, nextResource is set to
* null.
*/
private void findNextResource() {
URL url = null;
while ((pathElementsIndex < pathComponents.size()) && (url == null)) {
try {
final File pathComponent = pathComponents.elementAt(pathElementsIndex);
url = getResourceURL(pathComponent, this.resourceName);
pathElementsIndex++;
} catch (final BuildException e) {
// ignore path elements which are not valid relative to the
// project
}
}
this.nextResource = url;
}
}
/**
* The size of buffers to be used in this classloader.
*/
private static final int BUFFER_SIZE = 8192;
/**
* Number of array elements in a test array of strings
*/
private static final int NUMBER_OF_STRINGS = 256;
/**
* The components of the classpath that the classloader searches
* for classes.
*/
private final Vector pathComponents = new VectorSet<>();
/**
* The project to which this class loader belongs.
*/
private Project project;
/**
* Indicates whether the parent class loader should be
* consulted before trying to load with this class loader.
*/
private boolean parentFirst = true;
/**
* These are the package roots that are to be loaded by the parent class
* loader regardless of whether the parent class loader is being searched
* first or not.
*/
private final Vector systemPackages = new Vector<>();
/**
* These are the package roots that are to be loaded by this class loader
* regardless of whether the parent class loader is being searched first
* or not.
*/
private final Vector loaderPackages = new Vector<>();
/**
* Whether or not this classloader will ignore the base
* classloader if it can't find a class.
*
* @see #setIsolated(boolean)
*/
private boolean ignoreBase = false;
/**
* The parent class loader, if one is given or can be determined.
*/
private ClassLoader parent = null;
/**
* A hashtable of zip files opened by the classloader (File to JarFile).
*/
private Hashtable jarFiles = new Hashtable<>();
/** Static map of jar file/time to manifest class-path entries */
private static Map pathMap =
Collections.synchronizedMap(new HashMap());
/**
* The context loader saved when setting the thread's current
* context loader.
*/
private ClassLoader savedContextLoader = null;
/**
* Whether or not the context loader is currently saved.
*/
private boolean isContextLoaderSaved = false;
/**
* Create an Ant ClassLoader for a given project, with
* a parent classloader and an initial classpath.
* @since Ant 1.7.
* @param parent the parent for this classloader.
* @param project The project to which this classloader is to
* belong.
* @param classpath The classpath to use to load classes.
*/
public AntClassLoader(final ClassLoader parent, final Project project, final Path classpath) {
setParent(parent);
setClassPath(classpath);
setProject(project);
}
/**
* Create an Ant Class Loader
*/
public AntClassLoader() {
setParent(null);
}
/**
* Creates a classloader for the given project using the classpath given.
*
* @param project The project to which this classloader is to belong.
* Must not be null.
* @param classpath The classpath to use to load the classes. This
* is combined with the system classpath in a manner
* determined by the value of ${build.sysclasspath}.
* May be null, in which case no path
* elements are set up to start with.
*/
public AntClassLoader(final Project project, final Path classpath) {
setParent(null);
setProject(project);
setClassPath(classpath);
}
/**
* Creates a classloader for the given project using the classpath given.
*
* @param parent The parent classloader to which unsatisfied loading
* attempts are delegated. May be null,
* in which case the classloader which loaded this
* class is used as the parent.
* @param project The project to which this classloader is to belong.
* Must not be null.
* @param classpath the classpath to use to load the classes.
* May be null, in which case no path
* elements are set up to start with.
* @param parentFirst If true, indicates that the parent
* classloader should be consulted before trying to
* load the a class through this loader.
*/
public AntClassLoader(final ClassLoader parent, final Project project,
final Path classpath, final boolean parentFirst) {
this(project, classpath);
if (parent != null) {
setParent(parent);
}
setParentFirst(parentFirst);
addJavaLibraries();
}
/**
* Creates a classloader for the given project using the classpath given.
*
* @param project The project to which this classloader is to belong.
* Must not be null.
* @param classpath The classpath to use to load the classes. May be
* null, in which case no path
* elements are set up to start with.
* @param parentFirst If true, indicates that the parent
* classloader should be consulted before trying to
* load the a class through this loader.
*/
public AntClassLoader(final Project project, final Path classpath,
final boolean parentFirst) {
this(null, project, classpath, parentFirst);
}
/**
* Creates an empty class loader. The classloader should be configured
* with path elements to specify where the loader is to look for
* classes.
*
* @param parent The parent classloader to which unsatisfied loading
* attempts are delegated. May be null,
* in which case the classloader which loaded this
* class is used as the parent.
* @param parentFirst If true, indicates that the parent
* classloader should be consulted before trying to
* load the a class through this loader.
*/
public AntClassLoader(final ClassLoader parent, final boolean parentFirst) {
setParent(parent);
project = null;
this.parentFirst = parentFirst;
}
/**
* Set the project associated with this class loader
*
* @param project the project instance
*/
public void setProject(final Project project) {
this.project = project;
if (project != null) {
project.addBuildListener(this);
}
}
/**
* Set the classpath to search for classes to load. This should not be
* changed once the classloader starts to server classes
*
* @param classpath the search classpath consisting of directories and
* jar/zip files.
*/
public void setClassPath(final Path classpath) {
pathComponents.removeAllElements();
if (classpath != null) {
final Path actualClasspath = classpath.concatSystemClasspath("ignore");
final String[] pathElements = actualClasspath.list();
for (int i = 0; i < pathElements.length; ++i) {
try {
addPathElement(pathElements[i]);
} catch (final BuildException e) {
// ignore path elements which are invalid
// relative to the project
}
}
}
}
/**
* Set the parent for this class loader. This is the class loader to which
* this class loader will delegate to load classes
*
* @param parent the parent class loader.
*/
public void setParent(final ClassLoader parent) {
this.parent = parent == null ? AntClassLoader.class.getClassLoader() : parent;
}
/**
* Control whether class lookup is delegated to the parent loader first
* or after this loader. Use with extreme caution. Setting this to
* false violates the class loader hierarchy and can lead to Linkage errors
*
* @param parentFirst if true, delegate initial class search to the parent
* classloader.
*/
public void setParentFirst(final boolean parentFirst) {
this.parentFirst = parentFirst;
}
/**
* Logs a message through the project object if one has been provided.
*
* @param message The message to log.
* Should not be null.
*
* @param priority The logging priority of the message.
*/
protected void log(final String message, final int priority) {
if (project != null) {
project.log(message, priority);
} else if (priority < Project.MSG_INFO) {
System.err.println(message);
}
}
/**
* Sets the current thread's context loader to this classloader, storing
* the current loader value for later resetting.
*/
public void setThreadContextLoader() {
if (isContextLoaderSaved) {
throw new BuildException("Context loader has not been reset");
}
if (LoaderUtils.isContextLoaderAvailable()) {
savedContextLoader = LoaderUtils.getContextClassLoader();
ClassLoader loader = this;
if (project != null && "only".equals(project.getProperty("build.sysclasspath"))) {
loader = this.getClass().getClassLoader();
}
LoaderUtils.setContextClassLoader(loader);
isContextLoaderSaved = true;
}
}
/**
* Resets the current thread's context loader to its original value.
*/
public void resetThreadContextLoader() {
if (LoaderUtils.isContextLoaderAvailable() && isContextLoaderSaved) {
LoaderUtils.setContextClassLoader(savedContextLoader);
savedContextLoader = null;
isContextLoaderSaved = false;
}
}
/**
* Adds an element to the classpath to be searched.
*
* @param pathElement The path element to add. Must not be
* null.
*
* @exception BuildException if the given path element cannot be resolved
* against the project.
*/
public void addPathElement(final String pathElement) throws BuildException {
final File pathComponent = project != null ? project.resolveFile(pathElement) : new File(
pathElement);
try {
addPathFile(pathComponent);
} catch (final IOException e) {
throw new BuildException(e);
}
}
/**
* Add a path component.
* This simply adds the file, unlike addPathElement
* it does not open jar files and load files from
* their CLASSPATH entry in the manifest file.
* @param file the jar file or directory to add.
*/
public void addPathComponent(final File file) {
if (pathComponents.contains(file)) {
return;
}
pathComponents.addElement(file);
}
/**
* Add a file to the path.
* Reads the manifest, if available, and adds any additional class path jars
* specified in the manifest.
*
* @param pathComponent the file which is to be added to the path for
* this class loader
*
* @throws IOException if data needed from the file cannot be read.
*/
protected void addPathFile(final File pathComponent) throws IOException {
if (!pathComponents.contains(pathComponent)) {
pathComponents.addElement(pathComponent);
}
if (pathComponent.isDirectory()) {
return;
}
final String absPathPlusTimeAndLength = pathComponent.getAbsolutePath()
+ pathComponent.lastModified() + "-" + pathComponent.length();
String classpath = pathMap.get(absPathPlusTimeAndLength);
if (classpath == null) {
try (JarFile jarFile = new JarFile(pathComponent)) {
final Manifest manifest = jarFile.getManifest();
if (manifest == null) {
return;
}
classpath = manifest.getMainAttributes()
.getValue(Attributes.Name.CLASS_PATH);
}
if (classpath == null) {
classpath = "";
}
pathMap.put(absPathPlusTimeAndLength, classpath);
}
if (!"".equals(classpath)) {
final URL baseURL = FILE_UTILS.getFileURL(pathComponent);
final StringTokenizer st = new StringTokenizer(classpath);
while (st.hasMoreTokens()) {
final String classpathElement = st.nextToken();
final URL libraryURL = new URL(baseURL, classpathElement);
if (!libraryURL.getProtocol().equals("file")) {
log("Skipping jar library " + classpathElement
+ " since only relative URLs are supported by this" + " loader",
Project.MSG_VERBOSE);
continue;
}
final String decodedPath = Locator.decodeUri(libraryURL.getFile());
final File libraryFile = new File(decodedPath);
if (libraryFile.exists() && !isInPath(libraryFile)) {
addPathFile(libraryFile);
}
}
}
}
/**
* Returns the classpath this classloader will consult.
*
* @return the classpath used for this classloader, with elements
* separated by the path separator for the system.
*/
public String getClasspath() {
final StringBuilder sb = new StringBuilder();
boolean firstPass = true;
final Enumeration componentEnum = pathComponents.elements();
while (componentEnum.hasMoreElements()) {
if (!firstPass) {
sb.append(System.getProperty("path.separator"));
} else {
firstPass = false;
}
sb.append(componentEnum.nextElement().getAbsolutePath());
}
return sb.toString();
}
/**
* Sets whether this classloader should run in isolated mode. In
* isolated mode, classes not found on the given classpath will
* not be referred to the parent class loader but will cause a
* ClassNotFoundException.
*
* @param isolated Whether or not this classloader should run in
* isolated mode.
*/
public synchronized void setIsolated(final boolean isolated) {
ignoreBase = isolated;
}
/**
* Forces initialization of a class in a JDK 1.1 compatible, albeit hacky
* way.
*
* @param theClass The class to initialize.
* Must not be null.
*
* @deprecated since 1.6.x.
* Use Class.forName with initialize=true instead.
*/
@Deprecated
public static void initializeClass(final Class theClass) {
// ***HACK*** We ask the VM to create an instance
// by voluntarily providing illegal arguments to force
// the VM to run the class' static initializer, while
// at the same time not running a valid constructor.
final Constructor[] cons = theClass.getDeclaredConstructors();
//At least one constructor is guaranteed to be there, but check anyway.
if (cons != null) {
if (cons.length > 0 && cons[0] != null) {
final String[] strs = new String[NUMBER_OF_STRINGS];
try {
cons[0].newInstance((Object[]) strs);
// Expecting an exception to be thrown by this call:
// IllegalArgumentException: wrong number of Arguments
} catch (final Exception e) {
// Ignore - we are interested only in the side
// effect - that of getting the static initializers
// invoked. As we do not want to call a valid
// constructor to get this side effect, an
// attempt is made to call a hopefully
// invalid constructor - come on, nobody
// would have a constructor that takes in
// 256 String arguments ;-)
// (In fact, they can't - according to JVM spec
// section 4.10, the number of method parameters is limited
// to 255 by the definition of a method descriptor.
// Constructors count as methods here.)
}
}
}
}
/**
* Adds a package root to the list of packages which must be loaded on the
* parent loader.
*
* All subpackages are also included.
*
* @param packageRoot The root of all packages to be included.
* Should not be null.
*/
public void addSystemPackageRoot(final String packageRoot) {
systemPackages.addElement(packageRoot + (packageRoot.endsWith(".") ? "" : "."));
}
/**
* Adds a package root to the list of packages which must be loaded using
* this loader.
*
* All subpackages are also included.
*
* @param packageRoot The root of all packages to be included.
* Should not be null.
*/
public void addLoaderPackageRoot(final String packageRoot) {
loaderPackages.addElement(packageRoot + (packageRoot.endsWith(".") ? "" : "."));
}
/**
* Loads a class through this class loader even if that class is available
* on the parent classpath.
*
* This ensures that any classes which are loaded by the returned class
* will use this classloader.
*
* @param classname The name of the class to be loaded.
* Must not be null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
public Class forceLoadClass(final String classname) throws ClassNotFoundException {
log("force loading " + classname, Project.MSG_DEBUG);
Class theClass = findLoadedClass(classname);
if (theClass == null) {
theClass = findClass(classname);
}
return theClass;
}
/**
* Loads a class through this class loader but defer to the parent class
* loader.
*
* This ensures that instances of the returned class will be compatible
* with instances which have already been loaded on the parent
* loader.
*
* @param classname The name of the class to be loaded.
* Must not be null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
public Class forceLoadSystemClass(final String classname) throws ClassNotFoundException {
log("force system loading " + classname, Project.MSG_DEBUG);
Class theClass = findLoadedClass(classname);
if (theClass == null) {
theClass = findBaseClass(classname);
}
return theClass;
}
/**
* Returns a stream to read the requested resource name.
*
* @param name The name of the resource for which a stream is required.
* Must not be null.
*
* @return a stream to the required resource or null if the
* resource cannot be found on the loader's classpath.
*/
@Override
public InputStream getResourceAsStream(final String name) {
InputStream resourceStream = null;
if (isParentFirst(name)) {
resourceStream = loadBaseResource(name);
}
if (resourceStream != null) {
log("ResourceStream for " + name
+ " loaded from parent loader", Project.MSG_DEBUG);
} else {
resourceStream = loadResource(name);
if (resourceStream != null) {
log("ResourceStream for " + name
+ " loaded from ant loader", Project.MSG_DEBUG);
}
}
if (resourceStream == null && !isParentFirst(name)) {
if (ignoreBase) {
resourceStream = getRootLoader() == null
? null
: getRootLoader().getResourceAsStream(name);
} else {
resourceStream = loadBaseResource(name);
}
if (resourceStream != null) {
log("ResourceStream for " + name + " loaded from parent loader",
Project.MSG_DEBUG);
}
}
if (resourceStream == null) {
log("Couldn't load ResourceStream for " + name, Project.MSG_DEBUG);
}
return resourceStream;
}
/**
* Returns a stream to read the requested resource name from this loader.
*
* @param name The name of the resource for which a stream is required.
* Must not be null.
*
* @return a stream to the required resource or null if
* the resource cannot be found on the loader's classpath.
*/
private InputStream loadResource(final String name) {
// we need to search the components of the path to see if we can
// find the class we want.
InputStream stream = null;
final Enumeration e = pathComponents.elements();
while (e.hasMoreElements() && stream == null) {
final File pathComponent = e.nextElement();
stream = getResourceStream(pathComponent, name);
}
return stream;
}
/**
* Finds a system resource (which should be loaded from the parent
* classloader).
*
* @param name The name of the system resource to load.
* Must not be null.
*
* @return a stream to the named resource, or null if
* the resource cannot be found.
*/
private InputStream loadBaseResource(final String name) {
return parent == null ? super.getResourceAsStream(name) : parent.getResourceAsStream(name);
}
/**
* Returns an inputstream to a given resource in the given file which may
* either be a directory or a zip file.
*
* @param file the file (directory or jar) in which to search for the
* resource. Must not be null.
* @param resourceName The name of the resource for which a stream is
* required. Must not be null.
*
* @return a stream to the required resource or null if
* the resource cannot be found in the given file.
*/
private InputStream getResourceStream(final File file, final String resourceName) {
try {
JarFile jarFile = jarFiles.get(file);
if (jarFile == null && file.isDirectory()) {
final File resource = new File(file, resourceName);
if (resource.exists()) {
return Files.newInputStream(resource.toPath());
}
} else {
if (jarFile == null) {
if (file.exists()) {
jarFile = new JarFile(file);
jarFiles.put(file, jarFile);
} else {
return null;
}
//to eliminate a race condition, retrieve the entry
//that is in the hash table under that filename
jarFile = jarFiles.get(file);
}
final JarEntry entry = jarFile.getJarEntry(resourceName);
if (entry != null) {
return jarFile.getInputStream(entry);
}
}
} catch (final Exception e) {
log("Ignoring Exception " + e.getClass().getName() + ": " + e.getMessage()
+ " reading resource " + resourceName + " from " + file, Project.MSG_VERBOSE);
}
return null;
}
/**
* Tests whether or not the parent classloader should be checked for a
* resource before this one. If the resource matches both the "use parent
* classloader first" and the "use this classloader first" lists, the latter
* takes priority.
*
* @param resourceName
* The name of the resource to check. Must not be
* null.
*
* @return whether or not the parent classloader should be checked for a
* resource before this one is.
*/
private boolean isParentFirst(final String resourceName) {
// default to the global setting and then see
// if this class belongs to a package which has been
// designated to use a specific loader first
// (this one or the parent one)
// TODO - shouldn't this always return false in isolated mode?
boolean useParentFirst = parentFirst;
for (final Enumeration e = systemPackages.elements(); e.hasMoreElements();) {
final String packageName = e.nextElement();
if (resourceName.startsWith(packageName)) {
useParentFirst = true;
break;
}
}
for (final Enumeration e = loaderPackages.elements(); e.hasMoreElements();) {
final String packageName = e.nextElement();
if (resourceName.startsWith(packageName)) {
useParentFirst = false;
break;
}
}
return useParentFirst;
}
/**
* Used for isolated resource seaching.
* @return the root classloader of AntClassLoader.
*/
private ClassLoader getRootLoader() {
ClassLoader ret = getClass().getClassLoader();
while (ret != null && ret.getParent() != null) {
ret = ret.getParent();
}
return ret;
}
/**
* Finds the resource with the given name. A resource is
* some data (images, audio, text, etc) that can be accessed by class
* code in a way that is independent of the location of the code.
*
* @param name The name of the resource for which a stream is required.
* Must not be null.
*
* @return a URL for reading the resource, or null if the
* resource could not be found or the caller doesn't have
* adequate privileges to get the resource.
*/
@Override
public URL getResource(final String name) {
// we need to search the components of the path to see if
// we can find the class we want.
URL url = null;
if (isParentFirst(name)) {
url = parent == null ? super.getResource(name) : parent.getResource(name);
}
if (url != null) {
log("Resource " + name + " loaded from parent loader", Project.MSG_DEBUG);
} else {
// try and load from this loader if the parent either didn't find
// it or wasn't consulted.
final Enumeration e = pathComponents.elements();
while (e.hasMoreElements() && url == null) {
final File pathComponent = e.nextElement();
url = getResourceURL(pathComponent, name);
if (url != null) {
log("Resource " + name + " loaded from ant loader", Project.MSG_DEBUG);
}
}
}
if (url == null && !isParentFirst(name)) {
// this loader was first but it didn't find it - try the parent
if (ignoreBase) {
url = getRootLoader() == null ? null : getRootLoader().getResource(name);
} else {
url = parent == null ? super.getResource(name) : parent.getResource(name);
}
if (url != null) {
log("Resource " + name + " loaded from parent loader", Project.MSG_DEBUG);
}
}
if (url == null) {
log("Couldn't load Resource " + name, Project.MSG_DEBUG);
}
return url;
}
/**
* Finds all the resources with the given name. A resource is some
* data (images, audio, text, etc) that can be accessed by class
* code in a way that is independent of the location of the code.
*
* Would override getResources if that wasn't final in Java
* 1.4.
*
* @param name name of the resource
* @return possible URLs as enumeration
* @throws IOException if something goes wrong
* @see #findResources(String, boolean)
* @since Ant 1.8.0
*/
public Enumeration getNamedResources(final String name)
throws IOException {
return findResources(name, false);
}
/**
* Returns an enumeration of URLs representing all the resources with the
* given name by searching the class loader's classpath.
*
* @param name The resource name to search for.
* Must not be null.
* @return an enumeration of URLs for the resources
* @exception IOException if I/O errors occurs (can't happen)
*/
@Override
protected Enumeration findResources(final String name) throws IOException {
return findResources(name, true);
}
/**
* Returns an enumeration of URLs representing all the resources with the
* given name by searching the class loader's classpath.
*
* @param name The resource name to search for.
* Must not be null.
* @param parentHasBeenSearched whether ClassLoader.this.parent
* has been searched - will be true if the method is (indirectly)
* called from ClassLoader.getResources
* @return an enumeration of URLs for the resources
* @exception IOException if I/O errors occurs (can't happen)
*/
protected Enumeration findResources(final String name,
final boolean parentHasBeenSearched)
throws IOException {
final Enumeration mine = new ResourceEnumeration(name);
Enumeration base;
if (parent != null && (!parentHasBeenSearched || parent != getParent())) {
// Delegate to the parent:
base = parent.getResources(name);
// Note: could cause overlaps in case
// ClassLoader.this.parent has matches and
// parentHasBeenSearched is true
} else {
// ClassLoader.this.parent is already delegated to for example from
// ClassLoader.getResources, no need:
base = new CollectionUtils.EmptyEnumeration();
}
if (isParentFirst(name)) {
// Normal case.
return CollectionUtils.append(base, mine);
}
if (ignoreBase) {
return getRootLoader() == null ? mine : CollectionUtils.append(mine, getRootLoader()
.getResources(name));
}
// parent last:
return CollectionUtils.append(mine, base);
}
/**
* Returns the URL of a given resource in the given file which may
* either be a directory or a zip file.
*
* @param file The file (directory or jar) in which to search for
* the resource. Must not be null.
* @param resourceName The name of the resource for which a stream
* is required. Must not be null.
*
* @return a stream to the required resource or null if the
* resource cannot be found in the given file object.
*/
protected URL getResourceURL(final File file, final String resourceName) {
try {
JarFile jarFile = jarFiles.get(file);
if (jarFile == null && file.isDirectory()) {
final File resource = new File(file, resourceName);
if (resource.exists()) {
try {
return FILE_UTILS.getFileURL(resource);
} catch (final MalformedURLException ex) {
return null;
}
}
} else {
if (jarFile == null) {
if (file.exists()) {
if (!isZip(file)) {
final String msg = "CLASSPATH element " + file
+ " is not a JAR.";
log(msg, Project.MSG_WARN);
return null;
}
jarFile = new JarFile(file);
jarFiles.put(file, jarFile);
} else {
return null;
}
// potential race-condition
jarFile = jarFiles.get(file);
}
final JarEntry entry = jarFile.getJarEntry(resourceName);
if (entry != null) {
try {
return new URL("jar:" + FILE_UTILS.getFileURL(file) + "!/" + entry);
} catch (final MalformedURLException ex) {
return null;
}
}
}
} catch (final Exception e) {
final String msg = "Unable to obtain resource from " + file + ": ";
log(msg + e, Project.MSG_WARN);
log(StringUtils.getStackTrace(e), Project.MSG_WARN);
}
return null;
}
/**
* Loads a class with this class loader.
*
* This class attempts to load the class in an order determined by whether
* or not the class matches the system/loader package lists, with the
* loader package list taking priority. If the classloader is in isolated
* mode, failure to load the class in this loader will result in a
* ClassNotFoundException.
*
* @param classname The name of the class to be loaded.
* Must not be null.
* @param resolve true if all classes upon which this class
* depends are to be loaded.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on the system classpath (when not in isolated mode) or this loader's
* classpath.
*/
@Override
protected synchronized Class loadClass(final String classname, final boolean resolve)
throws ClassNotFoundException {
// 'sync' is needed - otherwise 2 threads can load the same class
// twice, resulting in LinkageError: duplicated class definition.
// findLoadedClass avoids that, but without sync it won't work.
Class theClass = findLoadedClass(classname);
if (theClass != null) {
return theClass;
}
if (isParentFirst(classname)) {
try {
theClass = findBaseClass(classname);
log("Class " + classname + " loaded from parent loader " + "(parentFirst)",
Project.MSG_DEBUG);
} catch (final ClassNotFoundException cnfe) {
theClass = findClass(classname);
log("Class " + classname + " loaded from ant loader " + "(parentFirst)",
Project.MSG_DEBUG);
}
} else {
try {
theClass = findClass(classname);
log("Class " + classname + " loaded from ant loader", Project.MSG_DEBUG);
} catch (final ClassNotFoundException cnfe) {
if (ignoreBase) {
throw cnfe;
}
theClass = findBaseClass(classname);
log("Class " + classname + " loaded from parent loader", Project.MSG_DEBUG);
}
}
if (resolve) {
resolveClass(theClass);
}
return theClass;
}
/**
* Converts the class dot notation to a filesystem equivalent for
* searching purposes.
*
* @param classname The class name in dot format (eg java.lang.Integer).
* Must not be null.
*
* @return the classname in filesystem format (eg java/lang/Integer.class)
*/
private String getClassFilename(final String classname) {
return classname.replace('.', '/') + ".class";
}
/**
* Define a class given its bytes
*
* @param container the container from which the class data has been read
* may be a directory or a jar/zip file.
*
* @param classData the bytecode data for the class
* @param classname the name of the class
*
* @return the Class instance created from the given data
*
* @throws IOException if the class data cannot be read.
*/
protected Class defineClassFromData(final File container, final byte[] classData, final String classname)
throws IOException {
definePackage(container, classname);
final ProtectionDomain currentPd = Project.class.getProtectionDomain();
final String classResource = getClassFilename(classname);
final CodeSource src = new CodeSource(FILE_UTILS.getFileURL(container),
getCertificates(container,
classResource));
final ProtectionDomain classesPd =
new ProtectionDomain(src, currentPd.getPermissions(),
this,
currentPd.getPrincipals());
return defineClass(classname, classData, 0, classData.length,
classesPd);
}
/**
* Define the package information associated with a class.
*
* @param container the file containing the class definition.
* @param className the class name of for which the package information
* is to be determined.
*
* @exception IOException if the package information cannot be read from the
* container.
*/
protected void definePackage(final File container, final String className) throws IOException {
final int classIndex = className.lastIndexOf('.');
if (classIndex == -1) {
return;
}
final String packageName = className.substring(0, classIndex);
if (getPackage(packageName) != null) {
// already defined
return;
}
// define the package now
final Manifest manifest = getJarManifest(container);
if (manifest == null) {
definePackage(packageName, null, null, null, null, null, null, null);
} else {
definePackage(container, packageName, manifest);
}
}
/**
* Get the manifest from the given jar, if it is indeed a jar and it has a
* manifest
*
* @param container the File from which a manifest is required.
*
* @return the jar's manifest or null is the container is not a jar or it
* has no manifest.
*
* @exception IOException if the manifest cannot be read.
*/
private Manifest getJarManifest(final File container) throws IOException {
if (container.isDirectory()) {
return null;
}
final JarFile jarFile = jarFiles.get(container);
if (jarFile == null) {
return null;
}
return jarFile.getManifest();
}
/**
* Get the certificates for a given jar entry, if it is indeed a jar.
*
* @param container the File from which to read the entry
* @param entry the entry of which the certificates are requested
*
* @return the entry's certificates or null is the container is
* not a jar or it has no certificates.
*/
private Certificate[] getCertificates(final File container, final String entry) {
if (container.isDirectory()) {
return null;
}
final JarFile jarFile = jarFiles.get(container);
if (jarFile == null) {
return null;
}
final JarEntry ent = jarFile.getJarEntry(entry);
return ent == null ? null : ent.getCertificates();
}
/**
* Define the package information when the class comes from a
* jar with a manifest
*
* @param container the jar file containing the manifest
* @param packageName the name of the package being defined.
* @param manifest the jar's manifest
*/
protected void definePackage(final File container, final String packageName, final Manifest manifest) {
final String sectionName = packageName.replace('.', '/') + "/";
String specificationTitle = null;
String specificationVendor = null;
String specificationVersion = null;
String implementationTitle = null;
String implementationVendor = null;
String implementationVersion = null;
String sealedString = null;
URL sealBase = null;
final Attributes sectionAttributes = manifest.getAttributes(sectionName);
if (sectionAttributes != null) {
specificationTitle = sectionAttributes.getValue(Name.SPECIFICATION_TITLE);
specificationVendor = sectionAttributes.getValue(Name.SPECIFICATION_VENDOR);
specificationVersion = sectionAttributes.getValue(Name.SPECIFICATION_VERSION);
implementationTitle = sectionAttributes.getValue(Name.IMPLEMENTATION_TITLE);
implementationVendor = sectionAttributes.getValue(Name.IMPLEMENTATION_VENDOR);
implementationVersion = sectionAttributes.getValue(Name.IMPLEMENTATION_VERSION);
sealedString = sectionAttributes.getValue(Name.SEALED);
}
final Attributes mainAttributes = manifest.getMainAttributes();
if (mainAttributes != null) {
if (specificationTitle == null) {
specificationTitle = mainAttributes.getValue(Name.SPECIFICATION_TITLE);
}
if (specificationVendor == null) {
specificationVendor = mainAttributes.getValue(Name.SPECIFICATION_VENDOR);
}
if (specificationVersion == null) {
specificationVersion = mainAttributes.getValue(Name.SPECIFICATION_VERSION);
}
if (implementationTitle == null) {
implementationTitle = mainAttributes.getValue(Name.IMPLEMENTATION_TITLE);
}
if (implementationVendor == null) {
implementationVendor = mainAttributes.getValue(Name.IMPLEMENTATION_VENDOR);
}
if (implementationVersion == null) {
implementationVersion = mainAttributes.getValue(Name.IMPLEMENTATION_VERSION);
}
if (sealedString == null) {
sealedString = mainAttributes.getValue(Name.SEALED);
}
}
if (sealedString != null && sealedString.equalsIgnoreCase("true")) {
try {
sealBase = new URL(FileUtils.getFileUtils().toURI(container.getAbsolutePath()));
} catch (final MalformedURLException e) {
// ignore
}
}
definePackage(packageName, specificationTitle, specificationVersion, specificationVendor,
implementationTitle, implementationVersion, implementationVendor, sealBase);
}
/**
* Reads a class definition from a stream.
*
* @param stream The stream from which the class is to be read.
* Must not be null.
* @param classname The name of the class in the stream.
* Must not be null.
* @param container the file or directory containing the class.
*
* @return the Class object read from the stream.
*
* @exception IOException if there is a problem reading the class from the
* stream.
* @exception SecurityException if there is a security problem while
* reading the class from the stream.
*/
private Class getClassFromStream(final InputStream stream, final String classname, final File container)
throws IOException, SecurityException {
final ByteArrayOutputStream baos = new ByteArrayOutputStream();
int bytesRead = -1;
final byte[] buffer = new byte[BUFFER_SIZE];
while ((bytesRead = stream.read(buffer, 0, BUFFER_SIZE)) != -1) {
baos.write(buffer, 0, bytesRead);
}
final byte[] classData = baos.toByteArray();
return defineClassFromData(container, classData, classname);
}
/**
* Searches for and load a class on the classpath of this class loader.
*
* @param name The name of the class to be loaded. Must not be
* null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
@Override
public Class findClass(final String name) throws ClassNotFoundException {
log("Finding class " + name, Project.MSG_DEBUG);
return findClassInComponents(name);
}
/**
* Indicate if the given file is in this loader's path
*
* @param component the file which is to be checked
*
* @return true if the file is in the class path
*/
protected boolean isInPath(final File component) {
return pathComponents.contains(component);
}
/**
* Finds a class on the given classpath.
*
* @param name The name of the class to be loaded. Must not be
* null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
private Class findClassInComponents(final String name)
throws ClassNotFoundException {
// we need to search the components of the path to see if
// we can find the class we want.
final String classFilename = getClassFilename(name);
final Enumeration e = pathComponents.elements();
while (e.hasMoreElements()) {
final File pathComponent = e.nextElement();
InputStream stream = null;
try {
stream = getResourceStream(pathComponent, classFilename);
if (stream != null) {
log("Loaded from " + pathComponent + " "
+ classFilename, Project.MSG_DEBUG);
return getClassFromStream(stream, name, pathComponent);
}
} catch (final SecurityException se) {
throw se;
} catch (final IOException ioe) {
// ioe.printStackTrace();
log("Exception reading component " + pathComponent + " (reason: "
+ ioe.getMessage() + ")", Project.MSG_VERBOSE);
} finally {
FileUtils.close(stream);
}
}
throw new ClassNotFoundException(name);
}
/**
* Finds a system class (which should be loaded from the same classloader
* as the Ant core).
*
* For JDK 1.1 compatibility, this uses the findSystemClass method if
* no parent classloader has been specified.
*
* @param name The name of the class to be loaded.
* Must not be null.
*
* @return the required Class object
*
* @exception ClassNotFoundException if the requested class does not exist
* on this loader's classpath.
*/
private Class findBaseClass(final String name) throws ClassNotFoundException {
return parent == null ? findSystemClass(name) : parent.loadClass(name);
}
/**
* Cleans up any resources held by this classloader. Any open archive
* files are closed.
*/
public synchronized void cleanup() {
for (final Enumeration e = jarFiles.elements(); e.hasMoreElements();) {
FileUtils.close(e.nextElement());
}
jarFiles = new Hashtable();
if (project != null) {
project.removeBuildListener(this);
}
project = null;
}
/**
* Gets the parent as has been specified in the constructor or via
* setParent.
*
* @return classloader
* @since Ant 1.8.0
*/
public ClassLoader getConfiguredParent() {
return parent;
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the buildStarted event
*/
public void buildStarted(final BuildEvent event) {
// Not significant for the class loader.
}
/**
* Cleans up any resources held by this classloader at the end
* of a build.
*
* @param event the buildFinished event
*/
public void buildFinished(final BuildEvent event) {
cleanup();
}
/**
* Cleans up any resources held by this classloader at the end of
* a subbuild if it has been created for the subbuild's project
* instance.
*
* @param event the buildFinished event
*
* @since Ant 1.6.2
*/
public void subBuildFinished(final BuildEvent event) {
if (event.getProject() == project) {
cleanup();
}
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the buildStarted event
*
* @since Ant 1.6.2
*/
public void subBuildStarted(final BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the targetStarted event
*/
public void targetStarted(final BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the targetFinished event
*/
public void targetFinished(final BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the taskStarted event
*/
public void taskStarted(final BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the taskFinished event
*/
public void taskFinished(final BuildEvent event) {
// Not significant for the class loader.
}
/**
* Empty implementation to satisfy the BuildListener interface.
*
* @param event the messageLogged event
*/
public void messageLogged(final BuildEvent event) {
// Not significant for the class loader.
}
/**
* add any libraries that come with different java versions
* here
*/
public void addJavaLibraries() {
final Vector packages = JavaEnvUtils.getJrePackages();
final Enumeration e = packages.elements();
while (e.hasMoreElements()) {
final String packageName = e.nextElement();
addSystemPackageRoot(packageName);
}
}
/**
* Returns a String representing this loader.
* @return the path that this classloader has.
*/
@Override
public String toString() {
return "AntClassLoader[" + getClasspath() + "]";
}
/** {@inheritDoc} */
@Override
public Enumeration getResources(String name) throws IOException {
return getNamedResources(name);
}
/** {@inheritDoc} */
public void close() {
cleanup();
}
/**
* Factory method
*
* @param parent ClassLoader
* @param project Project
* @param path Path
* @param parentFirst boolean
* @return AntClassLoader
*/
public static AntClassLoader newAntClassLoader(final ClassLoader parent,
final Project project,
final Path path,
final boolean parentFirst) {
return new AntClassLoader(parent, project, path, parentFirst);
}
private static final ZipLong EOCD_SIG = new ZipLong(0X06054B50L);
private static final ZipLong SINGLE_SEGMENT_SPLIT_MARKER =
new ZipLong(0X30304B50L);
private static boolean isZip(final File file) throws IOException {
final byte[] sig = new byte[4];
if (readFully(file, sig)) {
final ZipLong start = new ZipLong(sig);
return ZipLong.LFH_SIG.equals(start) // normal file
|| EOCD_SIG.equals(start) // empty zip
|| ZipLong.DD_SIG.equals(start) // split zip
|| SINGLE_SEGMENT_SPLIT_MARKER.equals(start);
}
return false;
}
private static boolean readFully(final File f, final byte[] b) throws IOException {
try (InputStream fis = Files.newInputStream(f.toPath())) {
final int len = b.length;
int count = 0, x = 0;
while (count != len) {
x = fis.read(b, count, len - count);
if (x == -1) {
break;
}
count += x;
}
return count == len;
}
}
}