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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.
/*
* Copyright 2014 - 2018 Rafael Winterhalter
*
* 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 net.bytebuddy;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import net.bytebuddy.build.CachedReturnPlugin;
import net.bytebuddy.build.HashCodeAndEqualsPlugin;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.dynamic.ClassFileLocator;
import net.bytebuddy.utility.OpenedClassReader;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Opcodes;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* A wrapper object for representing a validated class file version in the format that is specified by the
* JVMS.
*/
@HashCodeAndEqualsPlugin.Enhance
public class ClassFileVersion implements Comparable {
/**
* Returns the minimal version number that is legal.
*/
protected static final int BASE_VERSION = 44;
/**
* The class file version of Java 1.
*/
public static final ClassFileVersion JAVA_V1 = new ClassFileVersion(Opcodes.V1_1);
/**
* The class file version of Java 2.
*/
public static final ClassFileVersion JAVA_V2 = new ClassFileVersion(Opcodes.V1_2);
/**
* The class file version of Java 3.
*/
public static final ClassFileVersion JAVA_V3 = new ClassFileVersion(Opcodes.V1_3);
/**
* The class file version of Java 4.
*/
public static final ClassFileVersion JAVA_V4 = new ClassFileVersion(Opcodes.V1_4);
/**
* The class file version of Java 5.
*/
public static final ClassFileVersion JAVA_V5 = new ClassFileVersion(Opcodes.V1_5);
/**
* The class file version of Java 6.
*/
public static final ClassFileVersion JAVA_V6 = new ClassFileVersion(Opcodes.V1_6);
/**
* The class file version of Java 7.
*/
public static final ClassFileVersion JAVA_V7 = new ClassFileVersion(Opcodes.V1_7);
/**
* The class file version of Java 8.
*/
public static final ClassFileVersion JAVA_V8 = new ClassFileVersion(Opcodes.V1_8);
/**
* The class file version of Java 9.
*/
public static final ClassFileVersion JAVA_V9 = new ClassFileVersion(Opcodes.V9);
/**
* The class file version of Java 10.
*/
public static final ClassFileVersion JAVA_V10 = new ClassFileVersion(Opcodes.V10);
/**
* The class file version of Java 11.
*/
public static final ClassFileVersion JAVA_V11 = new ClassFileVersion(Opcodes.V11);
/**
* The class file version of Java 12 (preliminary).
*/
public static final ClassFileVersion JAVA_V12 = new ClassFileVersion(Opcodes.V12);
/**
* A version locator for the executing JVM.
*/
private static final VersionLocator VERSION_LOCATOR = AccessController.doPrivileged(VersionLocator.CreationAction.INSTANCE);
/**
* The version number that is represented by this class file version instance.
*/
private final int versionNumber;
/**
* Creates a wrapper for a given minor-major release of the Java class file file.
*
* @param versionNumber The minor-major release number.
*/
protected ClassFileVersion(int versionNumber) {
this.versionNumber = versionNumber;
}
/**
* Creates a wrapper for a given minor-major release of the Java class file file.
*
* @param versionNumber The minor-major release number.
* @return A representation of the version number.
*/
public static ClassFileVersion ofMinorMajor(int versionNumber) {
ClassFileVersion classFileVersion = new ClassFileVersion(versionNumber);
if (classFileVersion.getMajorVersion() <= BASE_VERSION) {
throw new IllegalArgumentException("Class version " + versionNumber + " is not valid");
}
return classFileVersion;
}
/**
* Returns the Java class file by its representation by a version string in accordance to the formats known to javac.
*
* @param javaVersionString The Java version string.
* @return The appropriate class file version.
*/
public static ClassFileVersion ofJavaVersionString(String javaVersionString) {
if (javaVersionString.equals("1.1")) {
return JAVA_V1;
} else if (javaVersionString.equals("1.2")) {
return JAVA_V2;
} else if (javaVersionString.equals("1.3")) {
return JAVA_V3;
} else if (javaVersionString.equals("1.4")) {
return JAVA_V4;
} else if (javaVersionString.equals("1.5") || javaVersionString.equals("5")) {
return JAVA_V5;
} else if (javaVersionString.equals("1.6") || javaVersionString.equals("6")) {
return JAVA_V6;
} else if (javaVersionString.equals("1.7") || javaVersionString.equals("7")) {
return JAVA_V7;
} else if (javaVersionString.equals("1.8") || javaVersionString.equals("8")) {
return JAVA_V8;
} else if (javaVersionString.equals("1.9") || javaVersionString.equals("9")) {
return JAVA_V9;
} else if (javaVersionString.equals("1.10") || javaVersionString.equals("10")) {
return JAVA_V10;
} else if (javaVersionString.equals("1.11") || javaVersionString.equals("11")) {
return JAVA_V11;
} else if (javaVersionString.equals("1.12") || javaVersionString.equals("12")) {
return JAVA_V12;
} else {
throw new IllegalArgumentException("Unknown Java version string: " + javaVersionString);
}
}
/**
* Creates a class file version for a given major release of Java. Currently, all versions reaching from
* Java 1 to Java 9 are supported.
*
* @param javaVersion The Java version.
* @return A wrapper for the given Java class file version.
*/
public static ClassFileVersion ofJavaVersion(int javaVersion) {
switch (javaVersion) {
case 1:
return JAVA_V1;
case 2:
return JAVA_V2;
case 3:
return JAVA_V3;
case 4:
return JAVA_V4;
case 5:
return JAVA_V5;
case 6:
return JAVA_V6;
case 7:
return JAVA_V7;
case 8:
return JAVA_V8;
case 9:
return JAVA_V9;
case 10:
return JAVA_V10;
case 11:
return JAVA_V11;
case 12:
return JAVA_V12;
default:
throw new IllegalArgumentException("Unknown Java version: " + javaVersion);
}
}
/**
* Finds the highest class file version that is compatible to the current JVM version. Prior to Java 9, this is achieved
* by parsing the {@code java.version} property which is provided by {@link java.lang.System#getProperty(String)}. If the system
* property is not available, an {@link IllegalStateException} is thrown.
*
* @return The currently running Java process's class file version.
*/
@CachedReturnPlugin.Enhance
public static ClassFileVersion ofThisVm() {
return VERSION_LOCATOR.locate();
}
/**
* Finds the highest class file version that is compatible to the current JVM version. Prior to Java 9, this is achieved
* by parsing the {@code java.version} property which is provided by {@link java.lang.System#getProperty(String)}. If the system
* property is not available, the {@code fallback} version is returned.
*
* @param fallback The version to fallback to if locating a class file version is not possible.
* @return The currently running Java process's class file version or the fallback if locating this version is impossible.
*/
@SuppressFBWarnings(value = "REC_CATCH_EXCEPTION", justification = "Exception should not be rethrown but trigger a fallback")
public static ClassFileVersion ofThisVm(ClassFileVersion fallback) {
try {
return ofThisVm();
} catch (Exception ignored) {
return fallback;
}
}
/**
* Extracts a class' class version. The class' byte code is located by querying the {@link ClassLoader} of the class.
*
* @param type The type for which to locate a class file version.
* @return The type's class file version.
* @throws IOException If an error occurs while reading the class file.
*/
public static ClassFileVersion of(Class type) throws IOException {
return of(type, ClassFileLocator.ForClassLoader.of(type.getClassLoader()));
}
/**
* Extracts a class' class version.
*
* @param type The type for which to locate a class file version.
* @param classFileLocator The class file locator to query for a class file.
* @return The type's class file version.
* @throws IOException If an error occurs while reading the class file.
*/
public static ClassFileVersion of(Class type, ClassFileLocator classFileLocator) throws IOException {
return of(TypeDescription.ForLoadedType.of(type), classFileLocator);
}
/**
* Extracts a class' class version.
*
* @param typeDescription The type for which to locate a class file version.
* @param classFileLocator The class file locator to query for a class file.
* @return The type's class file version.
* @throws IOException If an error occurs while reading the class file.
*/
public static ClassFileVersion of(TypeDescription typeDescription, ClassFileLocator classFileLocator) throws IOException {
ClassReader classReader = OpenedClassReader.of(classFileLocator.locate(typeDescription.getName()).resolve());
VersionExtractor versionExtractor = new VersionExtractor();
classReader.accept(versionExtractor, ClassReader.SKIP_CODE);
return ClassFileVersion.ofMinorMajor(versionExtractor.getClassFileVersionNumber());
}
/**
* Returns the minor-major release number of this class file version.
*
* @return The minor-major release number of this class file version.
*/
public int getMinorMajorVersion() {
return versionNumber;
}
/**
* Returns the major version this instance represents.
*
* @return The major version this instance represents.
*/
public int getMajorVersion() {
return versionNumber & 0xFF;
}
/**
* Returns the minor version this instance represents.
*
* @return The minor version this instance represents.
*/
public int getMinorVersion() {
return versionNumber >> 16;
}
/**
* Returns the Java runtime version number of this class file version.
*
* @return The Java runtime version.
*/
public int getJavaVersion() {
return getMajorVersion() - BASE_VERSION;
}
/**
* Checks if this class file version is at least as new as the provided version.
*
* @param classFileVersion The version to check against.
* @return {@code true} if this version is at least of the given version.
*/
public boolean isAtLeast(ClassFileVersion classFileVersion) {
return compareTo(classFileVersion) > -1;
}
/**
* Checks if this class file version is newer than the provided version.
*
* @param classFileVersion The version to check against.
* @return {@code true} if this version is newer than the provided version.
*/
public boolean isGreaterThan(ClassFileVersion classFileVersion) {
return compareTo(classFileVersion) > 0;
}
/**
* Checks if this class file version is at most as new as the provided version.
*
* @param classFileVersion The version to check against.
* @return {@code true} if this version is as most as new as the provided version.
*/
public boolean isAtMost(ClassFileVersion classFileVersion) {
return compareTo(classFileVersion) < 1;
}
/**
* Checks if this class file version is older than the provided version.
*
* @param classFileVersion The version to check against.
* @return {@code true} if this version is older than the provided version.
*/
public boolean isLessThan(ClassFileVersion classFileVersion) {
return compareTo(classFileVersion) < 0;
}
/**
* Returns this class file version indicating a class using preview features.
*
* @return This class file version but indicating the use of preview features.
*/
public ClassFileVersion asPreviewVersion() {
return new ClassFileVersion(versionNumber | Opcodes.V_PREVIEW);
}
/**
* Returns {@code true} if this class file version indicates the use of preview features.
*
* @return {@code true} if this class file version indicates the use of preview features.
*/
public boolean isPreviewVersion() {
return (versionNumber & Opcodes.V_PREVIEW) == Opcodes.V_PREVIEW;
}
/**
* {@inheritDoc}
*/
public int compareTo(ClassFileVersion other) {
return Integer.signum(getMajorVersion() == other.getMajorVersion()
? getMinorVersion() - other.getMinorVersion()
: getMajorVersion() - other.getMajorVersion());
}
@Override
public String toString() {
return "Java " + getJavaVersion();
}
/**
* A locator for the executing VM's Java version.
*/
protected interface VersionLocator {
/**
* Locates the current VM's major version number.
*
* @return The current VM's major version number.
*/
ClassFileVersion locate();
/**
* A creation action for a version locator.
*/
enum CreationAction implements PrivilegedAction {
/**
* The singleton instance.
*/
INSTANCE;
/**
* {@inheritDoc}
*/
@SuppressFBWarnings(value = "REC_CATCH_EXCEPTION", justification = "Exception should not be rethrown but trigger a fallback")
public VersionLocator run() {
try {
return new VersionLocator.ForJava9CapableVm(Runtime.class.getMethod("version"),
Class.forName("java.lang.Runtime$Version").getMethod("major"));
} catch (Exception ignored) {
return VersionLocator.ForLegacyVm.INSTANCE;
}
}
}
/**
* A version locator for a JVM of at least version 9.
*/
@HashCodeAndEqualsPlugin.Enhance
class ForJava9CapableVm implements VersionLocator {
/**
* Indicates that a reflective method call invokes a static method.
*/
private static final Object STATIC_METHOD = null;
/**
* The {@code java.lang.Runtime#version()} method.
*/
private final Method current;
/**
* The {@code java.lang.Runtime.Version#major()} method.
*/
private final Method major;
/**
* Creates a new version locator for a Java 9 capable VM.
*
* @param current The {@code java.lang.Runtime#version()} method.
* @param major The {@code java.lang.Runtime.Version#major()} method.
*/
protected ForJava9CapableVm(Method current, Method major) {
this.current = current;
this.major = major;
}
/**
* {@inheritDoc}
*/
public ClassFileVersion locate() {
try {
return ClassFileVersion.ofJavaVersion((Integer) major.invoke(current.invoke(STATIC_METHOD)));
} catch (IllegalAccessException exception) {
throw new IllegalStateException("Could not access VM version lookup", exception);
} catch (InvocationTargetException exception) {
throw new IllegalStateException("Could not look up VM version", exception.getCause());
}
}
}
/**
* A version locator for a JVM that does not provide the {@code java.lang.Runtime.Version} class.
*/
enum ForLegacyVm implements VersionLocator, PrivilegedAction {
/**
* The singleton instance.
*/
INSTANCE;
/**
* The system property for this JVM's Java version.
*/
private static final String JAVA_VERSION_PROPERTY = "java.version";
/**
* {@inheritDoc}
*/
public ClassFileVersion locate() {
String versionString = AccessController.doPrivileged(this);
int[] versionIndex = {-1, 0, 0};
for (int i = 1; i < 3; i++) {
versionIndex[i] = versionString.indexOf('.', versionIndex[i - 1] + 1);
if (versionIndex[i] == -1) {
throw new IllegalStateException("This JVM's version string does not seem to be valid: " + versionString);
}
}
return ClassFileVersion.ofJavaVersion(Integer.parseInt(versionString.substring(versionIndex[1] + 1, versionIndex[2])));
}
/**
* {@inheritDoc}
*/
public String run() {
return System.getProperty(JAVA_VERSION_PROPERTY);
}
}
}
/**
* A simple visitor that extracts the class file version of a class file.
*/
protected static class VersionExtractor extends ClassVisitor {
/**
* The class file version extracted from a class.
*/
private int classFileVersionNumber;
/**
* Creates a new extractor.
*/
protected VersionExtractor() {
super(OpenedClassReader.ASM_API);
}
@Override
public void visit(int classFileVersionNumber, int modifier, String internalName, String signature, String superTypeName, String[] interfaceName) {
this.classFileVersionNumber = classFileVersionNumber;
}
/**
* Returns the class file version number found in a class file.
*
* @return The class file version number found in a class file.
*/
protected int getClassFileVersionNumber() {
return classFileVersionNumber;
}
}
}
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