/*

  * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * 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).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  */

 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);

     // 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());

         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);

         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);

         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);

         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);

         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) {

                 // push receiver

                 Class<?> rcvrType = samType.parameterType(0);

                 visitVarInsn(getLoadOpcode(rcvrType), lvIndex + 1);

                 lvIndex += getParameterSize(rcvrType);

                 convertType(rcvrType, implDefiningClass, instantiatedMethodType.parameterType(0));

             }

             int samParametersLength = samType.parameterCount();

             int argOffset = implMethodType.parameterCount() - samParametersLength;

             for (int i = samReceiverLength; i < samParametersLength; i++) {

                 Class<?> argType = samType.parameterType(i);

                 visitVarInsn(getLoadOpcode(argType), lvIndex + 1);

                 lvIndex += getParameterSize(argType);

                 convertType(argType, implMethodType.parameterType(argOffset + i), instantiatedMethodType.parameterType(i));

             }

         }

         private int invocationOpcode() throws InternalError {

             switch (implKind) {

                 case MethodHandleInfo.REF_invokeStatic:

                     return INVOKESTATIC;

                 case MethodHandleInfo.REF_newInvokeSpecial:

                     return INVOKESPECIAL;

                  case MethodHandleInfo.REF_invokeVirtual:

                     return INVOKEVIRTUAL;

                 case MethodHandleInfo.REF_invokeInterface:

                     return INVOKEINTERFACE;

                 case MethodHandleInfo.REF_invokeSpecial:

                     return INVOKESPECIAL;

                 default:

                     throw new InternalError("Unexpected invocation kind: " + implKind);

             }

         }

     }

     static int getParameterSize(Class<?> c) {

         if (c == Void.TYPE) {

             return 0;

         } else if (c == Long.TYPE || c == Double.TYPE) {

             return 2;

         }

         return 1;

     }

     static int getLoadOpcode(Class<?> c) {

         if(c == Void.TYPE) {

             throw new InternalError("Unexpected void type of load opcode");

         }

         return ILOAD + getOpcodeOffset(c);

     }

     static int getReturnOpcode(Class<?> c) {

         if(c == Void.TYPE) {

             return RETURN;

         }

         return IRETURN + getOpcodeOffset(c);

     }

     private static int getOpcodeOffset(Class<?> c) {

         if (c.isPrimitive()) {

             if (c == Long.TYPE) {

                 return 1;

             } else if (c == Float.TYPE) {

                 return 2;

             } else if (c == Double.TYPE) {

                 return 3;

             }

             return 0;

         } else {

             return 4;

         }

     }

 }