JDK8/Java8源码在线阅读
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package java.lang.invoke;
import jdk.internal.org.objectweb.asm.*;
import sun.invoke.util.BytecodeDescriptor;
import sun.misc.Unsafe;
import sun.security.action.GetPropertyAction;
import java.io.FilePermission;
import java.io.Serializable;
import java.lang.reflect.Constructor;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.LinkedHashSet;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.PropertyPermission;
import java.util.Set;
import static jdk.internal.org.objectweb.asm.Opcodes.*;
/**
* Lambda metafactory implementation which dynamically creates an
* inner-class-like class per lambda callsite.
*
* @see LambdaMetafactory
*/
/* package */ final class InnerClassLambdaMetafactory extends AbstractValidatingLambdaMetafactory {
private static final Unsafe UNSAFE = Unsafe.getUnsafe();
private static final int CLASSFILE_VERSION = 52;
private static final String METHOD_DESCRIPTOR_VOID = Type.getMethodDescriptor(Type.VOID_TYPE);
private static final String JAVA_LANG_OBJECT = "java/lang/Object";
private static final String NAME_CTOR = "<init>";
private static final String NAME_FACTORY = "get$Lambda";
//Serialization support
private static final String NAME_SERIALIZED_LAMBDA = "java/lang/invoke/SerializedLambda";
private static final String NAME_NOT_SERIALIZABLE_EXCEPTION = "java/io/NotSerializableException";
private static final String DESCR_METHOD_WRITE_REPLACE = "()Ljava/lang/Object;";
private static final String DESCR_METHOD_WRITE_OBJECT = "(Ljava/io/ObjectOutputStream;)V";
private static final String DESCR_METHOD_READ_OBJECT = "(Ljava/io/ObjectInputStream;)V";
private static final String NAME_METHOD_WRITE_REPLACE = "writeReplace";
private static final String NAME_METHOD_READ_OBJECT = "readObject";
private static final String NAME_METHOD_WRITE_OBJECT = "writeObject";
private static final String DESCR_CTOR_SERIALIZED_LAMBDA
= MethodType.methodType(void.class,
Class.class,
String.class, String.class, String.class,
int.class, String.class, String.class, String.class,
String.class,
Object[].class).toMethodDescriptorString();
private static final String DESCR_CTOR_NOT_SERIALIZABLE_EXCEPTION
= MethodType.methodType(void.class, String.class).toMethodDescriptorString();
private static final String[] SER_HOSTILE_EXCEPTIONS = new String[] {NAME_NOT_SERIALIZABLE_EXCEPTION};
private static final String[] EMPTY_STRING_ARRAY = new String[0];
// Used to ensure that each spun class name is unique
private static final AtomicInteger counter = new AtomicInteger(0);
// For dumping generated classes to disk, for debugging purposes
private static final ProxyClassesDumper dumper;
static {
final String key = "jdk.internal.lambda.dumpProxyClasses";
String path = AccessController.doPrivileged(
new GetPropertyAction(key), null,
new PropertyPermission(key , "read"));
dumper = (null == path) ? null : ProxyClassesDumper.getInstance(path);
}
// See context values in AbstractValidatingLambdaMetafactory
private final String implMethodClassName; // Name of type containing implementation "CC"
private final String implMethodName; // Name of implementation method "impl"
private final String implMethodDesc; // Type descriptor for implementation methods "(I)Ljava/lang/String;"
private final Class<?> implMethodReturnClass; // class for implementaion method return type "Ljava/lang/String;"
private final MethodType constructorType; // Generated class constructor type "(CC)void"
private final ClassWriter cw; // ASM class writer
private final String[] argNames; // Generated names for the constructor arguments
private final String[] argDescs; // Type descriptors for the constructor arguments
private final String lambdaClassName; // Generated name for the generated class "X$$Lambda$1"
/**
* General meta-factory constructor, supporting both standard cases and
* allowing for uncommon options such as serialization or bridging.
*
* @param caller Stacked automatically by VM; represents a lookup context
* with the accessibility privileges of the caller.
* @param invokedType Stacked automatically by VM; the signature of the
* invoked method, which includes the expected static
* type of the returned lambda object, and the static
* types of the captured arguments for the lambda. In
* the event that the implementation method is an
* instance method, the first argument in the invocation
* signature will correspond to the receiver.
* @param samMethodName Name of the method in the functional interface to
* which the lambda or method reference is being
* converted, represented as a String.
* @param samMethodType Type of the method in the functional interface to
* which the lambda or method reference is being
* converted, represented as a MethodType.
* @param implMethod The implementation method which should be called (with
* suitable adaptation of argument types, return types,
* and adjustment for captured arguments) when methods of
* the resulting functional interface instance are invoked.
* @param instantiatedMethodType The signature of the primary functional
* interface method after type variables are
* substituted with their instantiation from
* the capture site
* @param isSerializable Should the lambda be made serializable? If set,
* either the target type or one of the additional SAM
* types must extend {@code Serializable}.
* @param markerInterfaces Additional interfaces which the lambda object
* should implement.
* @param additionalBridges Method types for additional signatures to be
* bridged to the implementation method
* @throws LambdaConversionException If any of the meta-factory protocol
* invariants are violated
*/
public InnerClassLambdaMetafactory(MethodHandles.Lookup caller,
MethodType invokedType,
String samMethodName,
MethodType samMethodType,
MethodHandle implMethod,
MethodType instantiatedMethodType,
boolean isSerializable,
Class<?>[] markerInterfaces,
MethodType[] additionalBridges)
throws LambdaConversionException {
super(caller, invokedType, samMethodName, samMethodType,
implMethod, instantiatedMethodType,
isSerializable, markerInterfaces, additionalBridges);
implMethodClassName = implDefiningClass.getName().replace('.', '/');
implMethodName = implInfo.getName();
implMethodDesc = implMethodType.toMethodDescriptorString();
implMethodReturnClass = (implKind == MethodHandleInfo.REF_newInvokeSpecial)
? implDefiningClass
: implMethodType.returnType();
constructorType = invokedType.changeReturnType(Void.TYPE);
lambdaClassName = targetClass.getName().replace('.', '/') + "$$Lambda$" + counter.incrementAndGet();
cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
int parameterCount = invokedType.parameterCount();
if (parameterCount > 0) {
argNames = new String[parameterCount];
argDescs = new String[parameterCount];
for (int i = 0; i < parameterCount; i++) {
argNames[i] = "arg$" + (i + 1);
argDescs[i] = BytecodeDescriptor.unparse(invokedType.parameterType(i));
}
} else {
argNames = argDescs = EMPTY_STRING_ARRAY;
}
}
/**
* Build the CallSite. Generate a class file which implements the functional
* interface, define the class, if there are no parameters create an instance
* of the class which the CallSite will return, otherwise, generate handles
* which will call the class' constructor.
*
* @return a CallSite, which, when invoked, will return an instance of the
* functional interface
* @throws ReflectiveOperationException
* @throws LambdaConversionException If properly formed functional interface
* is not found
*/
@Override
CallSite buildCallSite() throws LambdaConversionException {
final Class<?> innerClass = spinInnerClass();
if (invokedType.parameterCount() == 0) {
final Constructor<?>[] ctrs = AccessController.doPrivileged(
new PrivilegedAction<Constructor<?>[]>() {
@Override
public Constructor<?>[] run() {
Constructor<?>[] ctrs = innerClass.getDeclaredConstructors();
if (ctrs.length == 1) {
// The lambda implementing inner class constructor is private, set
// it accessible (by us) before creating the constant sole instance
ctrs[0].setAccessible(true);
}
return ctrs;
}
});
if (ctrs.length != 1) {
throw new LambdaConversionException("Expected one lambda constructor for "
+ innerClass.getCanonicalName() + ", got " + ctrs.length);
}
try {
Object inst = ctrs[0].newInstance();
return new ConstantCallSite(MethodHandles.constant(samBase, inst));
}
catch (ReflectiveOperationException e) {
throw new LambdaConversionException("Exception instantiating lambda object", e);
}
} else {
try {
UNSAFE.ensureClassInitialized(innerClass);
return new ConstantCallSite(
MethodHandles.Lookup.IMPL_LOOKUP
.findStatic(innerClass, NAME_FACTORY, invokedType));
}
catch (ReflectiveOperationException e) {
throw new LambdaConversionException("Exception finding constructor", e);
}
}
}
/**
* Generate a class file which implements the functional
* interface, define and return the class.
*
* @implNote The class that is generated does not include signature
* information for exceptions that may be present on the SAM method.
* This is to reduce classfile size, and is harmless as checked exceptions
* are erased anyway, no one will ever compile against this classfile,
* and we make no guarantees about the reflective properties of lambda
* objects.
*
* @return a Class which implements the functional interface
* @throws LambdaConversionException If properly formed functional interface
* is not found
*/
private Class<?> spinInnerClass() throws LambdaConversionException {
String[] interfaces;
String samIntf = samBase.getName().replace('.', '/');
boolean accidentallySerializable = !isSerializable && Serializable.class.isAssignableFrom(samBase);
if (markerInterfaces.length == 0) {
interfaces = new String[]{samIntf};
} else {
// Assure no duplicate interfaces (ClassFormatError)
Set<String> itfs = new LinkedHashSet<>(markerInterfaces.length + 1);
itfs.add(samIntf);
for (Class<?> markerInterface : markerInterfaces) {
itfs.add(markerInterface.getName().replace('.', '/'));
accidentallySerializable |= !isSerializable && Serializable.class.isAssignableFrom(markerInterface);
}
interfaces = itfs.toArray(new String[itfs.size()]);
}
cw.visit(CLASSFILE_VERSION, ACC_SUPER + ACC_FINAL + ACC_SYNTHETIC,
lambdaClassName, null,
JAVA_LANG_OBJECT, interfaces);
// Generate final fields to be filled in by constructor
for (int i = 0; i < argDescs.length; i++) {
FieldVisitor fv = cw.visitField(ACC_PRIVATE + ACC_FINAL,
argNames[i],
argDescs[i],
null, null);
fv.visitEnd();
}
generateConstructor();
if (invokedType.parameterCount() != 0) {
generateFactory();
}
// Forward the SAM method
MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, samMethodName,
samMethodType.toMethodDescriptorString(), null, null);
new ForwardingMethodGenerator(mv).generate(samMethodType);
// Forward the bridges
if (additionalBridges != null) {
for (MethodType mt : additionalBridges) {
mv = cw.visitMethod(ACC_PUBLIC|ACC_BRIDGE, samMethodName,
mt.toMethodDescriptorString(), null, null);
new ForwardingMethodGenerator(mv).generate(mt);
}
}
if (isSerializable)
generateSerializationFriendlyMethods();
else if (accidentallySerializable)
generateSerializationHostileMethods();
cw.visitEnd();
// Define the generated class in this VM.
final byte[] classBytes = cw.toByteArray();
// If requested, dump out to a file for debugging purposes
if (dumper != null) {
AccessController.doPrivileged(new PrivilegedAction<Void>() {
@Override
public Void run() {
dumper.dumpClass(lambdaClassName, classBytes);
return null;
}
}, null,
new FilePermission("<<ALL FILES>>", "read, write"),
// createDirectories may need it
new PropertyPermission("user.dir", "read"));
}
return UNSAFE.defineAnonymousClass(targetClass, classBytes, null);
}
/**
* Generate the factory method for the class
*/
private void generateFactory() {
MethodVisitor m = cw.visitMethod(ACC_PRIVATE | ACC_STATIC, NAME_FACTORY, invokedType.toMethodDescriptorString(), null, null);
m.visitCode();
m.visitTypeInsn(NEW, lambdaClassName);
m.visitInsn(Opcodes.DUP);
int parameterCount = invokedType.parameterCount();
for (int typeIndex = 0, varIndex = 0; typeIndex < parameterCount; typeIndex++) {
Class<?> argType = invokedType.parameterType(typeIndex);
m.visitVarInsn(getLoadOpcode(argType), varIndex);
varIndex += getParameterSize(argType);
}
m.visitMethodInsn(INVOKESPECIAL, lambdaClassName, NAME_CTOR, constructorType.toMethodDescriptorString(), false);
m.visitInsn(ARETURN);
m.visitMaxs(-1, -1);
m.visitEnd();
}
/**
* Generate the constructor for the class
*/
private void generateConstructor() {
// Generate constructor
MethodVisitor ctor = cw.visitMethod(ACC_PRIVATE, NAME_CTOR,
constructorType.toMethodDescriptorString(), null, null);
ctor.visitCode();
ctor.visitVarInsn(ALOAD, 0);
ctor.visitMethodInsn(INVOKESPECIAL, JAVA_LANG_OBJECT, NAME_CTOR,
METHOD_DESCRIPTOR_VOID, false);
int parameterCount = invokedType.parameterCount();
for (int i = 0, lvIndex = 0; i < parameterCount; i++) {
ctor.visitVarInsn(ALOAD, 0);
Class<?> argType = invokedType.parameterType(i);
ctor.visitVarInsn(getLoadOpcode(argType), lvIndex + 1);
lvIndex += getParameterSize(argType);
ctor.visitFieldInsn(PUTFIELD, lambdaClassName, argNames[i], argDescs[i]);
}
ctor.visitInsn(RETURN);
// Maxs computed by ClassWriter.COMPUTE_MAXS, these arguments ignored
ctor.visitMaxs(-1, -1);
ctor.visitEnd();
}
/**
* Generate a writeReplace method that supports serialization
*/
private void generateSerializationFriendlyMethods() {
TypeConvertingMethodAdapter mv
= new TypeConvertingMethodAdapter(
cw.visitMethod(ACC_PRIVATE + ACC_FINAL,
NAME_METHOD_WRITE_REPLACE, DESCR_METHOD_WRITE_REPLACE,
null, null));
mv.visitCode();
mv.visitTypeInsn(NEW, NAME_SERIALIZED_LAMBDA);
mv.visitInsn(DUP);
mv.visitLdcInsn(Type.getType(targetClass));
mv.visitLdcInsn(invokedType.returnType().getName().replace('.', '/'));
mv.visitLdcInsn(samMethodName);
mv.visitLdcInsn(samMethodType.toMethodDescriptorString());
mv.visitLdcInsn(implInfo.getReferenceKind());
mv.visitLdcInsn(implInfo.getDeclaringClass().getName().replace('.', '/'));
mv.visitLdcInsn(implInfo.getName());
mv.visitLdcInsn(implInfo.getMethodType().toMethodDescriptorString());
mv.visitLdcInsn(instantiatedMethodType.toMethodDescriptorString());
mv.iconst(argDescs.length);
mv.visitTypeInsn(ANEWARRAY, JAVA_LANG_OBJECT);
for (int i = 0; i < argDescs.length; i++) {
mv.visitInsn(DUP);
mv.iconst(i);
mv.visitVarInsn(ALOAD, 0);
mv.visitFieldInsn(GETFIELD, lambdaClassName, argNames[i], argDescs[i]);
mv.boxIfTypePrimitive(Type.getType(argDescs[i]));
mv.visitInsn(AASTORE);
}
mv.visitMethodInsn(INVOKESPECIAL, NAME_SERIALIZED_LAMBDA, NAME_CTOR,
DESCR_CTOR_SERIALIZED_LAMBDA, false);
mv.visitInsn(ARETURN);
// Maxs computed by ClassWriter.COMPUTE_MAXS, these arguments ignored
mv.visitMaxs(-1, -1);
mv.visitEnd();
}
/**
* Generate a readObject/writeObject method that is hostile to serialization
*/
private void generateSerializationHostileMethods() {
MethodVisitor mv = cw.visitMethod(ACC_PRIVATE + ACC_FINAL,
NAME_METHOD_WRITE_OBJECT, DESCR_METHOD_WRITE_OBJECT,
null, SER_HOSTILE_EXCEPTIONS);
mv.visitCode();
mv.visitTypeInsn(NEW, NAME_NOT_SERIALIZABLE_EXCEPTION);
mv.visitInsn(DUP);
mv.visitLdcInsn("Non-serializable lambda");
mv.visitMethodInsn(INVOKESPECIAL, NAME_NOT_SERIALIZABLE_EXCEPTION, NAME_CTOR,
DESCR_CTOR_NOT_SERIALIZABLE_EXCEPTION, false);
mv.visitInsn(ATHROW);
mv.visitMaxs(-1, -1);
mv.visitEnd();
mv = cw.visitMethod(ACC_PRIVATE + ACC_FINAL,
NAME_METHOD_READ_OBJECT, DESCR_METHOD_READ_OBJECT,
null, SER_HOSTILE_EXCEPTIONS);
mv.visitCode();
mv.visitTypeInsn(NEW, NAME_NOT_SERIALIZABLE_EXCEPTION);
mv.visitInsn(DUP);
mv.visitLdcInsn("Non-serializable lambda");
mv.visitMethodInsn(INVOKESPECIAL, NAME_NOT_SERIALIZABLE_EXCEPTION, NAME_CTOR,
DESCR_CTOR_NOT_SERIALIZABLE_EXCEPTION, false);
mv.visitInsn(ATHROW);
mv.visitMaxs(-1, -1);
mv.visitEnd();
}
/**
* This class generates a method body which calls the lambda implementation
* method, converting arguments, as needed.
*/
private class ForwardingMethodGenerator extends TypeConvertingMethodAdapter {
ForwardingMethodGenerator(MethodVisitor mv) {
super(mv);
}
void generate(MethodType methodType) {
visitCode();
if (implKind == MethodHandleInfo.REF_newInvokeSpecial) {
visitTypeInsn(NEW, implMethodClassName);
visitInsn(DUP);
}
for (int i = 0; i < argNames.length; i++) {
visitVarInsn(ALOAD, 0);
visitFieldInsn(GETFIELD, lambdaClassName, argNames[i], argDescs[i]);
}
convertArgumentTypes(methodType);
// Invoke the method we want to forward to
visitMethodInsn(invocationOpcode(), implMethodClassName,
implMethodName, implMethodDesc,
implDefiningClass.isInterface());
// Convert the return value (if any) and return it
// Note: if adapting from non-void to void, the 'return'
// instruction will pop the unneeded result
Class<?> samReturnClass = methodType.returnType();
convertType(implMethodReturnClass, samReturnClass, samReturnClass);
visitInsn(getReturnOpcode(samReturnClass));
// Maxs computed by ClassWriter.COMPUTE_MAXS,these arguments ignored
visitMaxs(-1, -1);
visitEnd();
}
private void convertArgumentTypes(MethodType samType) {
int lvIndex = 0;
boolean samIncludesReceiver = implIsInstanceMethod &&
invokedType.parameterCount() == 0;
int samReceiverLength = samIncludesReceiver ? 1 : 0;
if (samIncludesReceiver) {
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