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Byte Buddy is a Java library for creating Java classes at run time.
This artifact is a build of Byte Buddy with a remaining dependency onto ASM.
You should never depend on this module without repackaging Byte Buddy and ASM into your own namespace.
package net.bytebuddy.dynamic.loading;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.utility.RandomString;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.instrument.Instrumentation;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.security.ProtectionDomain;
import java.util.HashMap;
import java.util.Map;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.JarOutputStream;
/**
*
* A class injector is capable of injecting classes into a {@link java.lang.ClassLoader} without
* requiring the class loader to being able to explicitly look up these classes.
*
*
* Important: Byte Buddy does not supply privileges when injecting code. When using a {@link SecurityManager},
* the user of this injector is responsible for providing access to non-public properties.
*
*/
public interface ClassInjector {
/**
* A convenience reference to the default protection domain which is {@code null}.
*/
ProtectionDomain DEFAULT_PROTECTION_DOMAIN = null;
/**
* Determines the default behavior for type injections when a type is already loaded.
*/
boolean DEFAULT_FORBID_EXISTING = false;
/**
* Injects the given types into the represented class loader.
*
* @param types The types to load via injection.
* @return The loaded types that were passed as arguments.
*/
Map> inject(Map types);
/**
* A class injector that uses reflective method calls.
*/
class UsingReflection implements ClassInjector {
/**
* Indicates that an array should be included from the first index position. Improves source code readabilty.
*/
private static final int FROM_BEGINNING = 0;
/**
* The dispatcher to use for accessing a class loader via reflection.
*/
private static final Dispatcher.Initializable DISPATCHER = dispatcher();
/**
* Obtains the reflective instances used by this injector or a no-op instance that throws the exception
* that occurred when attempting to obtain the reflective member instances.
*
* @return A dispatcher for the current VM.
*/
@SuppressFBWarnings(value = "REC_CATCH_EXCEPTION", justification = "Exception should not be rethrown but trigger a fallback")
private static Dispatcher.Initializable dispatcher() {
try {
return new Dispatcher.Resolved(ClassLoader.class.getDeclaredMethod("findLoadedClass", String.class),
ClassLoader.class.getDeclaredMethod("defineClass",
String.class,
byte[].class,
int.class,
int.class,
ProtectionDomain.class),
ClassLoader.class.getDeclaredMethod("getPackage", String.class),
ClassLoader.class.getDeclaredMethod("definePackage",
String.class,
String.class,
String.class,
String.class,
String.class,
String.class,
String.class,
URL.class));
} catch (Exception exception) {
return new Dispatcher.Faulty(exception);
}
}
/**
* The class loader into which the classes are to be injected.
*/
private final ClassLoader classLoader;
/**
* The protection domain that is used when loading classes.
*/
private final ProtectionDomain protectionDomain;
/**
* The package definer to be queried for package definitions.
*/
private final PackageDefinitionStrategy packageDefinitionStrategy;
/**
* Determines if an exception should be thrown when attempting to load a type that already exists.
*/
private final boolean forbidExisting;
/**
* Creates a new injector for the given {@link java.lang.ClassLoader} and a default {@link java.security.ProtectionDomain} and a
* trivial {@link PackageDefinitionStrategy} which does not trigger an error when discovering existent classes.
*
* @param classLoader The {@link java.lang.ClassLoader} into which new class definitions are to be injected.
*/
public UsingReflection(ClassLoader classLoader) {
this(classLoader, DEFAULT_PROTECTION_DOMAIN);
}
/**
* Creates a new injector for the given {@link java.lang.ClassLoader} and a default {@link PackageDefinitionStrategy} where the
* injection of existent classes does not trigger an error.
*
* @param classLoader The {@link java.lang.ClassLoader} into which new class definitions are to be injected.
* @param protectionDomain The protection domain to apply during class definition.
*/
public UsingReflection(ClassLoader classLoader, ProtectionDomain protectionDomain) {
this(classLoader,
protectionDomain,
PackageDefinitionStrategy.Trivial.INSTANCE,
DEFAULT_FORBID_EXISTING);
}
/**
* Creates a new injector for the given {@link java.lang.ClassLoader} and {@link java.security.ProtectionDomain}.
*
* @param classLoader The {@link java.lang.ClassLoader} into which new class definitions are to be injected.
* @param protectionDomain The protection domain to apply during class definition.
* @param packageDefinitionStrategy The package definer to be queried for package definitions.
* @param forbidExisting Determines if an exception should be thrown when attempting to load a type that already exists.
*/
public UsingReflection(ClassLoader classLoader,
ProtectionDomain protectionDomain,
PackageDefinitionStrategy packageDefinitionStrategy,
boolean forbidExisting) {
if (classLoader == null) {
throw new IllegalArgumentException("Cannot inject classes into the bootstrap class loader");
}
this.classLoader = classLoader;
this.protectionDomain = protectionDomain;
this.packageDefinitionStrategy = packageDefinitionStrategy;
this.forbidExisting = forbidExisting;
}
/**
* Creates a class injector for the system class loader.
*
* @return A class injector for the system class loader.
*/
public static ClassInjector ofSystemClassLoader() {
return new UsingReflection(ClassLoader.getSystemClassLoader());
}
@Override
public Map> inject(Map types) {
synchronized (classLoader) {
Map> loadedTypes = new HashMap>();
for (Map.Entry entry : types.entrySet()) {
String typeName = entry.getKey().getName();
Dispatcher dispatcher = DISPATCHER.initialize();
Class type = dispatcher.findClass(classLoader, typeName);
if (type == null) {
int packageIndex = typeName.lastIndexOf('.');
if (packageIndex != -1) {
String packageName = typeName.substring(0, packageIndex);
PackageDefinitionStrategy.Definition definition = packageDefinitionStrategy.define(classLoader, packageName, typeName);
if (definition.isDefined()) {
Package definedPackage = dispatcher.getPackage(classLoader, packageName);
if (definedPackage == null) {
dispatcher.definePackage(classLoader,
packageName,
definition.getSpecificationTitle(),
definition.getSpecificationVersion(),
definition.getSpecificationVendor(),
definition.getImplementationTitle(),
definition.getImplementationVersion(),
definition.getImplementationVendor(),
definition.getSealBase());
} else if (!definition.isCompatibleTo(definedPackage)) {
throw new SecurityException("Sealing violation for package " + packageName);
}
}
}
byte[] binaryRepresentation = entry.getValue();
type = dispatcher.loadClass(classLoader,
typeName,
binaryRepresentation,
FROM_BEGINNING,
binaryRepresentation.length,
protectionDomain);
} else if (forbidExisting) {
throw new IllegalStateException("Cannot inject already loaded type: " + type);
}
loadedTypes.put(entry.getKey(), type);
}
return loadedTypes;
}
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
UsingReflection that = (UsingReflection) other;
return classLoader.equals(that.classLoader)
&& forbidExisting == that.forbidExisting
&& packageDefinitionStrategy.equals(that.packageDefinitionStrategy)
&& !(protectionDomain != null ? !protectionDomain.equals(that.protectionDomain) : that.protectionDomain != null);
}
@Override
public int hashCode() {
int result = classLoader.hashCode();
result = 31 * result + (protectionDomain != null ? protectionDomain.hashCode() : 0);
result = 31 * result + (forbidExisting ? 1 : 0);
result = 31 * result + packageDefinitionStrategy.hashCode();
return result;
}
@Override
public String toString() {
return "ClassInjector.UsingReflection{" +
"classLoader=" + classLoader +
", protectionDomain=" + protectionDomain +
", packageDefinitionStrategy=" + packageDefinitionStrategy +
", forbidExisting=" + forbidExisting +
'}';
}
/**
* A dispatcher for accessing a {@link ClassLoader} reflectively.
*/
protected interface Dispatcher {
/**
* Looks up a class from the given class loader.
*
* @param classLoader The class loader for which a class should be located.
* @param name The binary name of the class that should be located.
* @return The class for the binary name or {@code null} if no such class is defined for the provided class loader.
*/
Class findClass(ClassLoader classLoader, String name);
/**
* Defines a class for the given class loader.
*
* @param classLoader The class loader for which a new class should be defined.
* @param name The binary name of the class that should be defined.
* @param binaryRepresentation The binary representation of the class.
* @param startIndex The start index of the provided binary representation.
* @param endIndex The final index of the binary representation.
* @param protectionDomain The protection domain for the defined class.
* @return The defined, loaded class.
*/
Class loadClass(ClassLoader classLoader,
String name,
byte[] binaryRepresentation,
int startIndex,
int endIndex,
ProtectionDomain protectionDomain);
/**
* Looks up a package from a class loader.
*
* @param classLoader The class loader to query.
* @param name The binary name of the package.
* @return The package for the given name as defined by the provided class loader or {@code null} if no such package exists.
*/
Package getPackage(ClassLoader classLoader, String name);
/**
* Defines a package for the given class loader.
*
* @param classLoader The class loader for which a package is to be defined.
* @param packageName The binary name of the package.
* @param specificationTitle The specification title of the package or {@code null} if no specification title exists.
* @param specificationVersion The specification version of the package or {@code null} if no specification version exists.
* @param specificationVendor The specification vendor of the package or {@code null} if no specification vendor exists.
* @param implementationTitle The implementation title of the package or {@code null} if no implementation title exists.
* @param implementationVersion The implementation version of the package or {@code null} if no implementation version exists.
* @param implementationVendor The implementation vendor of the package or {@code null} if no implementation vendor exists.
* @param sealBase The seal base URL or {@code null} if the package should not be sealed.
* @return The defined package.
*/
Package definePackage(ClassLoader classLoader,
String packageName,
String specificationTitle,
String specificationVersion,
String specificationVendor,
String implementationTitle,
String implementationVersion,
String implementationVendor,
URL sealBase);
/**
* Initializes a dispatcher to make non-accessible APIs accessible.
*/
interface Initializable {
/**
* Initializes this dispatcher.
*
* @return The initiailized dispatcher.
*/
Dispatcher initialize();
}
/**
* Represents a successfully loaded method lookup for the dispatcher.
*/
class Resolved implements Dispatcher, Initializable {
/**
* An accessible instance of {@link ClassLoader#findLoadedClass(String)}.
*/
private final Method findLoadedClass;
/**
* An accessible instance of {@link ClassLoader#loadClass(String)}.
*/
private final Method loadClass;
/**
* An accessible instance of {@link ClassLoader#getPackage(String)}.
*/
private final Method getPackage;
/**
* An accessible instance of {@link ClassLoader#definePackage(String, String, String, String, String, String, String, URL)}.
*/
private final Method definePackage;
/**
* Creates a new resolved reflection store.
*
* @param findLoadedClass An accessible instance of {@link ClassLoader#findLoadedClass(String)}.
* @param loadClass An accessible instance of {@link ClassLoader#loadClass(String)}.
* @param getPackage An accessible instance of {@link ClassLoader#getPackage(String)}.
* @param definePackage An accessible instance of
* {@link ClassLoader#definePackage(String, String, String, String, String, String, String, URL)}.
*/
protected Resolved(Method findLoadedClass, Method loadClass, Method getPackage, Method definePackage) {
this.findLoadedClass = findLoadedClass;
this.loadClass = loadClass;
this.getPackage = getPackage;
this.definePackage = definePackage;
}
@Override
public Class findClass(ClassLoader classLoader, String name) {
try {
return (Class) findLoadedClass.invoke(classLoader, name);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Could not access java.lang.ClassLoader#findClass", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.ClassLoader#findClass", exception.getCause());
}
}
@Override
public Class loadClass(ClassLoader classLoader,
String name,
byte[] binaryRepresentation,
int startIndex,
int endIndex,
ProtectionDomain protectionDomain) {
try {
return (Class) loadClass.invoke(classLoader, name, binaryRepresentation, startIndex, endIndex, protectionDomain);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Could not access java.lang.ClassLoader#findClass", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.ClassLoader#findClass", exception.getCause());
}
}
@Override
public Package getPackage(ClassLoader classLoader, String name) {
try {
return (Package) getPackage.invoke(classLoader, name);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Could not access java.lang.ClassLoader#findClass", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.ClassLoader#findClass", exception.getCause());
}
}
@Override
public Package definePackage(ClassLoader classLoader,
String packageName,
String specificationTitle,
String specificationVersion,
String specificationVendor,
String implementationTitle,
String implementationVersion,
String implementationVendor,
URL sealBase) {
try {
return (Package) definePackage.invoke(classLoader,
packageName,
specificationTitle,
specificationVersion,
specificationVendor,
implementationTitle,
implementationVersion,
implementationVendor,
sealBase);
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Could not access java.lang.ClassLoader#findClass", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Error invoking java.lang.ClassLoader#findClass", exception.getCause());
}
}
@Override
@SuppressFBWarnings(value = "DP_DO_INSIDE_DO_PRIVILEGED", justification = "Privilege is explicit user responsibility")
public Dispatcher initialize() {
// This is safe even in a multi-threaded environment as all threads set the instances accessible before invoking any methods.
// By always setting accessability, the security manager is always triggered if this operation was illegal.
findLoadedClass.setAccessible(true);
loadClass.setAccessible(true);
getPackage.setAccessible(true);
definePackage.setAccessible(true);
return this;
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
Resolved resolved = (Resolved) other;
return findLoadedClass.equals(resolved.findLoadedClass)
&& loadClass.equals(resolved.loadClass)
&& getPackage.equals(resolved.getPackage)
&& definePackage.equals(resolved.definePackage);
}
@Override
public int hashCode() {
int result = findLoadedClass.hashCode();
result = 31 * result + loadClass.hashCode();
result = 31 * result + getPackage.hashCode();
result = 31 * result + definePackage.hashCode();
return result;
}
@Override
public String toString() {
return "ClassInjector.UsingReflection.Dispatcher.Resolved{" +
"findLoadedClass=" + findLoadedClass +
", loadClass=" + loadClass +
", getPackage=" + getPackage +
", definePackage=" + definePackage +
'}';
}
}
/**
* Represents an unsuccessfully loaded method lookup.
*/
class Faulty implements Initializable {
/**
* The exception that occurred when looking up the reflection methods.
*/
private final Exception exception;
/**
* Creates a new faulty reflection store.
*
* @param exception The exception that was thrown when attempting to lookup the method.
*/
protected Faulty(Exception exception) {
this.exception = exception;
}
@Override
public Dispatcher initialize() {
throw new IllegalStateException("Error locating class loader API", exception);
}
@Override
public boolean equals(Object other) {
return this == other || !(other == null || getClass() != other.getClass())
&& exception.equals(((Faulty) other).exception);
}
@Override
public int hashCode() {
return exception.hashCode();
}
@Override
public String toString() {
return "ClassInjector.UsingReflection.Dispatcher.Faulty{exception=" + exception + '}';
}
}
}
}
/**
* A class injector using a {@link java.lang.instrument.Instrumentation} to append to either the boot classpath
* or the system class path.
*/
class UsingInstrumentation implements ClassInjector {
/**
* A prefix to use of generated files.
*/
private static final String PREFIX = "jar";
/**
* The class file extension.
*/
private static final String CLASS_FILE_EXTENSION = ".class";
/**
* The instrumentation to use for appending to the class path or the boot path.
*/
private final Instrumentation instrumentation;
/**
* A representation of the target path to which classes are to be appended.
*/
private final Target target;
/**
* The folder to be used for storing jar files.
*/
private final File folder;
/**
* A random string generator for creating file names.
*/
private final RandomString randomString;
/**
* Creates an instrumentation-based class injector.
*
* @param folder The folder to be used for storing jar files.
* @param target A representation of the target path to which classes are to be appended.
* @param instrumentation The instrumentation to use for appending to the class path or the boot path.
* @return An appropriate class injector that applies instrumentation.
*/
public static ClassInjector of(File folder, Target target, Instrumentation instrumentation) {
return new UsingInstrumentation(folder, target, instrumentation, new RandomString());
}
/**
* Creates an instrumentation-based class injector.
*
* @param folder The folder to be used for storing jar files.
* @param target A representation of the target path to which classes are to be appended.
* @param instrumentation The instrumentation to use for appending to the class path or the boot path.
* @param randomString The random string generator to use.
*/
protected UsingInstrumentation(File folder,
Target target,
Instrumentation instrumentation,
RandomString randomString) {
this.folder = folder;
this.target = target;
this.instrumentation = instrumentation;
this.randomString = randomString;
}
@Override
public Map> inject(Map types) {
File jarFile = new File(folder, String.format("%s%s.jar", PREFIX, randomString.nextString()));
try {
if (!jarFile.createNewFile()) {
throw new IllegalStateException("Cannot create file " + jarFile);
}
JarOutputStream jarOutputStream = new JarOutputStream(new FileOutputStream(jarFile));
try {
for (Map.Entry entry : types.entrySet()) {
jarOutputStream.putNextEntry(new JarEntry(entry.getKey().getInternalName() + CLASS_FILE_EXTENSION));
jarOutputStream.write(entry.getValue());
}
} finally {
jarOutputStream.close();
}
target.inject(instrumentation, new JarFile(jarFile));
Map> loaded = new HashMap>();
for (TypeDescription typeDescription : types.keySet()) {
loaded.put(typeDescription, Class.forName(typeDescription.getName(), false, ClassLoader.getSystemClassLoader()));
}
return loaded;
} catch (IOException exception) {
throw new IllegalStateException("Cannot write jar file to disk", exception);
} catch (ClassNotFoundException exception) {
throw new IllegalStateException("Cannot load injected class", exception);
}
}
@Override
public boolean equals(Object other) {
if (this == other) return true;
if (other == null || getClass() != other.getClass()) return false;
UsingInstrumentation that = (UsingInstrumentation) other;
return folder.equals(that.folder)
&& instrumentation.equals(that.instrumentation)
&& target == that.target
&& randomString.equals(that.randomString);
}
@Override
public int hashCode() {
int result = instrumentation.hashCode();
result = 31 * result + target.hashCode();
result = 31 * result + folder.hashCode();
result = 31 * result + randomString.hashCode();
return result;
}
@Override
public String toString() {
return "ClassInjector.UsingInstrumentation{" +
"instrumentation=" + instrumentation +
", target=" + target +
", folder=" + folder +
", randomString=" + randomString +
'}';
}
/**
* A representation of the target to which Java classes should be appended to.
*/
public enum Target {
/**
* Representation of the bootstrap class loader.
*/
BOOTSTRAP {
@Override
protected void inject(Instrumentation instrumentation, JarFile jarFile) {
instrumentation.appendToBootstrapClassLoaderSearch(jarFile);
}
},
/**
* Representation of the system class loader.
*/
SYSTEM {
@Override
protected void inject(Instrumentation instrumentation, JarFile jarFile) {
instrumentation.appendToSystemClassLoaderSearch(jarFile);
}
};
/**
* Adds the given classes to the represented class loader.
*
* @param instrumentation The instrumentation instance to use.
* @param jarFile The jar file to append.
*/
protected abstract void inject(Instrumentation instrumentation, JarFile jarFile);
@Override
public String toString() {
return "ClassInjector.UsingInstrumentation.Target." + name();
}
}
}
}
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