/*

 * Copyright (c) 2008, 2015, 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 static jdk.internal.org.objectweb.asm.Opcodes.*;

import static java.lang.invoke.LambdaForm.*;

import static java.lang.invoke.LambdaForm.BasicType.*;

import static java.lang.invoke.MethodHandleStatics.*;

import java.lang.invoke.LambdaForm.NamedFunction;

import java.lang.invoke.MethodHandles.Lookup;

import java.lang.reflect.Field;

import java.util.Arrays;

import java.util.HashMap;

import sun.invoke.util.ValueConversions;

import sun.invoke.util.Wrapper;

import jdk.internal.org.objectweb.asm.ClassWriter;

import jdk.internal.org.objectweb.asm.MethodVisitor;

import jdk.internal.org.objectweb.asm.Type;

/**

 * The flavor of method handle which emulates an invoke instruction

 * on a predetermined argument.  The JVM dispatches to the correct method

 * when the handle is created, not when it is invoked.

 *

 * All bound arguments are encapsulated in dedicated species.

 */

/*non-public*/ abstract class BoundMethodHandle extends MethodHandle {

    /*non-public*/ BoundMethodHandle(MethodType type, LambdaForm form) {

        super(type, form);

        assert(speciesData() == speciesData(form));

    }

    //

    // BMH API and internals

    //

    static BoundMethodHandle bindSingle(MethodType type, LambdaForm form, BasicType xtype, Object x) {

        // for some type signatures, there exist pre-defined concrete BMH classes

        try {

            switch (xtype) {

            case L_TYPE:

                return bindSingle(type, form, x);  // Use known fast path.

            case I_TYPE:

                return (BoundMethodHandle) SpeciesData.EMPTY.extendWith(I_TYPE).constructor().invokeBasic(type, form, ValueConversions.widenSubword(x));

            case J_TYPE:

                return (BoundMethodHandle) SpeciesData.EMPTY.extendWith(J_TYPE).constructor().invokeBasic(type, form, (long) x);

            case F_TYPE:

                return (BoundMethodHandle) SpeciesData.EMPTY.extendWith(F_TYPE).constructor().invokeBasic(type, form, (float) x);

            case D_TYPE:

                return (BoundMethodHandle) SpeciesData.EMPTY.extendWith(D_TYPE).constructor().invokeBasic(type, form, (double) x);

            default : throw newInternalError("unexpected xtype: " + xtype);

            }

        } catch (Throwable t) {

            throw newInternalError(t);

        }

    }

    /*non-public*/

    LambdaFormEditor editor() {

        return form.editor();

    }

    static BoundMethodHandle bindSingle(MethodType type, LambdaForm form, Object x) {

        return Species_L.make(type, form, x);

    }

    @Override // there is a default binder in the super class, for 'L' types only

    /*non-public*/

    BoundMethodHandle bindArgumentL(int pos, Object value) {

        return editor().bindArgumentL(this, pos, value);

    }

    /*non-public*/

    BoundMethodHandle bindArgumentI(int pos, int value) {

        return editor().bindArgumentI(this, pos, value);

    }

    /*non-public*/

    BoundMethodHandle bindArgumentJ(int pos, long value) {

        return editor().bindArgumentJ(this, pos, value);

    }

    /*non-public*/

    BoundMethodHandle bindArgumentF(int pos, float value) {

        return editor().bindArgumentF(this, pos, value);

    }

    /*non-public*/

    BoundMethodHandle bindArgumentD(int pos, double value) {

        return editor().bindArgumentD(this, pos, value);

    }

    @Override

    BoundMethodHandle rebind() {

        if (!tooComplex()) {

            return this;

        }

        return makeReinvoker(this);

    }

    private boolean tooComplex() {

        return (fieldCount() > FIELD_COUNT_THRESHOLD ||

                form.expressionCount() > FORM_EXPRESSION_THRESHOLD);

    }

    private static final int FIELD_COUNT_THRESHOLD = 12;      // largest convenient BMH field count

    private static final int FORM_EXPRESSION_THRESHOLD = 24;  // largest convenient BMH expression count

    /**

     * A reinvoker MH has this form:

     * {@code lambda (bmh, arg*) { thismh = bmh[0]; invokeBasic(thismh, arg*) }}

     */

    static BoundMethodHandle makeReinvoker(MethodHandle target) {

        LambdaForm form = DelegatingMethodHandle.makeReinvokerForm(

                target, MethodTypeForm.LF_REBIND,

                Species_L.SPECIES_DATA, Species_L.SPECIES_DATA.getterFunction(0));

        return Species_L.make(target.type(), form, target);

    }

    /**

     * Return the {@link SpeciesData} instance representing this BMH species. All subclasses must provide a

     * static field containing this value, and they must accordingly implement this method.

     */

    /*non-public*/ abstract SpeciesData speciesData();

    /*non-public*/ static SpeciesData speciesData(LambdaForm form) {

        Object c = form.names[0].constraint;

        if (c instanceof SpeciesData)

            return (SpeciesData) c;

        // if there is no BMH constraint, then use the null constraint

        return SpeciesData.EMPTY;

    }

    /**

     * Return the number of fields in this BMH.  Equivalent to speciesData().fieldCount().

     */

    /*non-public*/ abstract int fieldCount();

    @Override

    Object internalProperties() {

        return "\n& BMH="+internalValues();

    }

    @Override

    final Object internalValues() {

        Object[] boundValues = new Object[speciesData().fieldCount()];

        for (int i = 0; i < boundValues.length; ++i) {

            boundValues[i] = arg(i);

        }

        return Arrays.asList(boundValues);

    }

    /*non-public*/ final Object arg(int i) {

        try {

            switch (speciesData().fieldType(i)) {

            case L_TYPE: return          speciesData().getters[i].invokeBasic(this);

            case I_TYPE: return (int)    speciesData().getters[i].invokeBasic(this);

            case J_TYPE: return (long)   speciesData().getters[i].invokeBasic(this);

            case F_TYPE: return (float)  speciesData().getters[i].invokeBasic(this);

            case D_TYPE: return (double) speciesData().getters[i].invokeBasic(this);

            }

        } catch (Throwable ex) {

            throw newInternalError(ex);

        }

        throw new InternalError("unexpected type: " + speciesData().typeChars+"."+i);

    }

    //

    // cloning API

    //

    /*non-public*/ abstract BoundMethodHandle copyWith(MethodType mt, LambdaForm lf);

    /*non-public*/ abstract BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg);

    /*non-public*/ abstract BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int    narg);

    /*non-public*/ abstract BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long   narg);

    /*non-public*/ abstract BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float  narg);

    /*non-public*/ abstract BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg);

    //

    // concrete BMH classes required to close bootstrap loops

    //

    private  // make it private to force users to access the enclosing class first

    static final class Species_L extends BoundMethodHandle {

        final Object argL0;

        private Species_L(MethodType mt, LambdaForm lf, Object argL0) {

            super(mt, lf);

            this.argL0 = argL0;

        }

        @Override

        /*non-public*/ SpeciesData speciesData() {

            return SPECIES_DATA;

        }

        @Override

        /*non-public*/ int fieldCount() {

            return 1;

        }

        /*non-public*/ static final SpeciesData SPECIES_DATA = SpeciesData.getForClass("L", Species_L.class);

        /*non-public*/ static BoundMethodHandle make(MethodType mt, LambdaForm lf, Object argL0) {

            return new Species_L(mt, lf, argL0);

        }

        @Override

        /*non-public*/ final BoundMethodHandle copyWith(MethodType mt, LambdaForm lf) {

            return new Species_L(mt, lf, argL0);

        }

        @Override

        /*non-public*/ final BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg) {

            try {

                return (BoundMethodHandle) SPECIES_DATA.extendWith(L_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);

            } catch (Throwable ex) {

                throw uncaughtException(ex);

            }

        }

        @Override

        /*non-public*/ final BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg) {

            try {

                return (BoundMethodHandle) SPECIES_DATA.extendWith(I_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);

            } catch (Throwable ex) {

                throw uncaughtException(ex);

            }

        }

        @Override

        /*non-public*/ final BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg) {

            try {

                return (BoundMethodHandle) SPECIES_DATA.extendWith(J_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);

            } catch (Throwable ex) {

                throw uncaughtException(ex);

            }

        }

        @Override

        /*non-public*/ final BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg) {

            try {

                return (BoundMethodHandle) SPECIES_DATA.extendWith(F_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);

            } catch (Throwable ex) {

                throw uncaughtException(ex);

            }

        }

        @Override

        /*non-public*/ final BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg) {

            try {

                return (BoundMethodHandle) SPECIES_DATA.extendWith(D_TYPE).constructor().invokeBasic(mt, lf, argL0, narg);

            } catch (Throwable ex) {

                throw uncaughtException(ex);

            }

        }

    }

    //

    // BMH species meta-data

    //

    /**

     * Meta-data wrapper for concrete BMH types.

     * Each BMH type corresponds to a given sequence of basic field types (LIJFD).

     * The fields are immutable; their values are fully specified at object construction.

     * Each BMH type supplies an array of getter functions which may be used in lambda forms.

     * A BMH is constructed by cloning a shorter BMH and adding one or more new field values.

     * The shortest possible BMH has zero fields; its class is SimpleMethodHandle.

     * BMH species are not interrelated by subtyping, even though it would appear that

     * a shorter BMH could serve as a supertype of a longer one which extends it.

     */

    static class SpeciesData {

        private final String                             typeChars;

        private final BasicType[]                        typeCodes;

        private final Class<? extends BoundMethodHandle> clazz;

        // Bootstrapping requires circular relations MH -> BMH -> SpeciesData -> MH

        // Therefore, we need a non-final link in the chain.  Use array elements.

        @Stable private final MethodHandle[]             constructor;

        @Stable private final MethodHandle[]             getters;

        @Stable private final NamedFunction[]            nominalGetters;

        @Stable private final SpeciesData[]              extensions;

        /*non-public*/ int fieldCount() {

            return typeCodes.length;

        }

        /*non-public*/ BasicType fieldType(int i) {

            return typeCodes[i];

        }

        /*non-public*/ char fieldTypeChar(int i) {

            return typeChars.charAt(i);

        }

        Object fieldSignature() {

            return typeChars;

        }

        public Class<? extends BoundMethodHandle> fieldHolder() {

            return clazz;

        }

        public String toString() {

            return "SpeciesData<"+fieldSignature()+">";

        }

        /**

         * Return a {@link LambdaForm.Name} containing a {@link LambdaForm.NamedFunction} that

         * represents a MH bound to a generic invoker, which in turn forwards to the corresponding

         * getter.

         */

        NamedFunction getterFunction(int i) {

            NamedFunction nf = nominalGetters[i];

            assert(nf.memberDeclaringClassOrNull() == fieldHolder());

            assert(nf.returnType() == fieldType(i));

            return nf;

        }

        NamedFunction[] getterFunctions() {

            return nominalGetters;

        }

        MethodHandle[] getterHandles() { return getters; }

        MethodHandle constructor() {

            return constructor[0];

        }

        static final SpeciesData EMPTY = new SpeciesData("", BoundMethodHandle.class);

        private SpeciesData(String types, Class<? extends BoundMethodHandle> clazz) {

            this.typeChars = types;

            this.typeCodes = basicTypes(types);

            this.clazz = clazz;

            if (!INIT_DONE) {

                this.constructor = new MethodHandle[1];  // only one ctor

                this.getters = new MethodHandle[types.length()];

                this.nominalGetters = new NamedFunction[types.length()];

            } else {

                this.constructor = Factory.makeCtors(clazz, types, null);

                this.getters = Factory.makeGetters(clazz, types, null);

                this.nominalGetters = Factory.makeNominalGetters(types, null, this.getters);

            }

            this.extensions = new SpeciesData[ARG_TYPE_LIMIT];

        }

        private void initForBootstrap() {

            assert(!INIT_DONE);

            if (constructor() == null) {

                String types = typeChars;

                Factory.makeCtors(clazz, types, this.constructor);

                Factory.makeGetters(clazz, types, this.getters);

                Factory.makeNominalGetters(types, this.nominalGetters, this.getters);

            }

        }

        private SpeciesData(String typeChars) {

            // Placeholder only.

            this.typeChars = typeChars;

            this.typeCodes = basicTypes(typeChars);

            this.clazz = null;

            this.constructor = null;

            this.getters = null;

            this.nominalGetters = null;

            this.extensions = null;

        }

        private boolean isPlaceholder() { return clazz == null; }

        private static final HashMap<String, SpeciesData> CACHE = new HashMap<>();

        static { CACHE.put("", EMPTY); }  // make bootstrap predictable

        private static final boolean INIT_DONE;  // set after <clinit> finishes...

        SpeciesData extendWith(byte type) {

            return extendWith(BasicType.basicType(type));

        }

        SpeciesData extendWith(BasicType type) {

            int ord = type.ordinal();

            SpeciesData d = extensions[ord];

            if (d != null)  return d;

            extensions[ord] = d = get(typeChars+type.basicTypeChar());

            return d;

        }

        private static SpeciesData get(String types) {

            // Acquire cache lock for query.

            SpeciesData d = lookupCache(types);

            if (!d.isPlaceholder())

                return d;

            synchronized (d) {

                // Use synch. on the placeholder to prevent multiple instantiation of one species.

                // Creating this class forces a recursive call to getForClass.

                if (lookupCache(types).isPlaceholder())

                    Factory.generateConcreteBMHClass(types);

            }

            // Reacquire cache lock.

            d = lookupCache(types);

            // Class loading must have upgraded the cache.

            assert(d != null && !d.isPlaceholder());

            return d;

        }

        static SpeciesData getForClass(String types, Class<? extends BoundMethodHandle> clazz) {

            // clazz is a new class which is initializing its SPECIES_DATA field

            return updateCache(types, new SpeciesData(types, clazz));

        }

        private static synchronized SpeciesData lookupCache(String types) {

            SpeciesData d = CACHE.get(types);

            if (d != null)  return d;

            d = new SpeciesData(types);

            assert(d.isPlaceholder());

            CACHE.put(types, d);

            return d;

        }

        private static synchronized SpeciesData updateCache(String types, SpeciesData d) {

            SpeciesData d2;

            assert((d2 = CACHE.get(types)) == null || d2.isPlaceholder());

            assert(!d.isPlaceholder());

            CACHE.put(types, d);

            return d;

        }

        static {

            // pre-fill the BMH speciesdata cache with BMH's inner classes

            final Class<BoundMethodHandle> rootCls = BoundMethodHandle.class;

            try {

                for (Class<?> c : rootCls.getDeclaredClasses()) {

                    if (rootCls.isAssignableFrom(c)) {

                        final Class<? extends BoundMethodHandle> cbmh = c.asSubclass(BoundMethodHandle.class);

                        SpeciesData d = Factory.speciesDataFromConcreteBMHClass(cbmh);

                        assert(d != null) : cbmh.getName();

                        assert(d.clazz == cbmh);

                        assert(d == lookupCache(d.typeChars));

                    }

                }

            } catch (Throwable e) {

                throw newInternalError(e);

            }

            for (SpeciesData d : CACHE.values()) {

                d.initForBootstrap();

            }

            // Note:  Do not simplify this, because INIT_DONE must not be

            // a compile-time constant during bootstrapping.

            INIT_DONE = Boolean.TRUE;

        }

    }

    static SpeciesData getSpeciesData(String types) {

        return SpeciesData.get(types);

    }

    /**

     * Generation of concrete BMH classes.

     *

     * A concrete BMH species is fit for binding a number of values adhering to a

     * given type pattern. Reference types are erased.

     *

     * BMH species are cached by type pattern.

     *

     * A BMH species has a number of fields with the concrete (possibly erased) types of

     * bound values. Setters are provided as an API in BMH. Getters are exposed as MHs,

     * which can be included as names in lambda forms.

     */

    static class Factory {

        static final String JLO_SIG  = "Ljava/lang/Object;";

        static final String JLS_SIG  = "Ljava/lang/String;";

        static final String JLC_SIG  = "Ljava/lang/Class;";

        static final String MH       = "java/lang/invoke/MethodHandle";

        static final String MH_SIG   = "L"+MH+";";

        static final String BMH      = "java/lang/invoke/BoundMethodHandle";

        static final String BMH_SIG  = "L"+BMH+";";

        static final String SPECIES_DATA     = "java/lang/invoke/BoundMethodHandle$SpeciesData";

        static final String SPECIES_DATA_SIG = "L"+SPECIES_DATA+";";

        static final String SPECIES_PREFIX_NAME = "Species_";

        static final String SPECIES_PREFIX_PATH = BMH + "$" + SPECIES_PREFIX_NAME;

        static final String BMHSPECIES_DATA_EWI_SIG = "(B)" + SPECIES_DATA_SIG;

        static final String BMHSPECIES_DATA_GFC_SIG = "(" + JLS_SIG + JLC_SIG + ")" + SPECIES_DATA_SIG;