/*

 * Copyright (c) 2008, 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 static java.lang.invoke.LambdaForm.basicTypes;

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

import java.lang.invoke.LambdaForm.Name;

import java.lang.invoke.LambdaForm.NamedFunction;

import java.lang.invoke.MethodHandles.Lookup;

import java.util.Arrays;

import java.util.HashMap;

import sun.invoke.util.ValueConversions;

/**

 * 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);

    }

    //

    // BMH API and internals

    //

    static MethodHandle bindSingle(MethodType type, LambdaForm form, char xtype, Object x) {

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

        try {

            switch (xtype) {

            case 'L':

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

                return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('L').constructor[0].invokeBasic(type, form, x);

            case 'I':

                return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('I').constructor[0].invokeBasic(type, form, ValueConversions.widenSubword(x));

            case 'J':

                return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('J').constructor[0].invokeBasic(type, form, (long) x);

            case 'F':

                return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('F').constructor[0].invokeBasic(type, form, (float) x);

            case 'D':

                return (BoundMethodHandle) SpeciesData.EMPTY.extendWithType('D').constructor[0].invokeBasic(type, form, (double) x);

            default : throw new InternalError("unexpected xtype: " + xtype);

            }

        } catch (Throwable t) {

            throw newInternalError(t);

        }

    }

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

            return new Species_L(type, form, x);

    }

    MethodHandle cloneExtend(MethodType type, LambdaForm form, char xtype, Object x) {

        try {

            switch (xtype) {

            case 'L': return cloneExtendL(type, form, x);

            case 'I': return cloneExtendI(type, form, ValueConversions.widenSubword(x));

            case 'J': return cloneExtendJ(type, form, (long) x);

            case 'F': return cloneExtendF(type, form, (float) x);

            case 'D': return cloneExtendD(type, form, (double) x);

            }

        } catch (Throwable t) {

            throw newInternalError(t);

        }

        throw new InternalError("unexpected type: " + xtype);

    }

    @Override

    MethodHandle bindArgument(int pos, char basicType, Object value) {

        MethodType type = type().dropParameterTypes(pos, pos+1);

        LambdaForm form = internalForm().bind(1+pos, speciesData());

        return cloneExtend(type, form, basicType, value);

    }

    @Override

    MethodHandle dropArguments(MethodType srcType, int pos, int drops) {

        LambdaForm form = internalForm().addArguments(pos, srcType.parameterList().subList(pos, pos+drops));

        try {

             return clone(srcType, form);

         } catch (Throwable t) {

             throw newInternalError(t);

         }

    }

    @Override

    MethodHandle permuteArguments(MethodType newType, int[] reorder) {

        try {

             return clone(newType, form.permuteArguments(1, reorder, basicTypes(newType.parameterList())));

         } catch (Throwable t) {

             throw newInternalError(t);

         }

    }

    static final String EXTENSION_TYPES = "LIJFD";

    static final byte INDEX_L = 0, INDEX_I = 1, INDEX_J = 2, INDEX_F = 3, INDEX_D = 4;

    static byte extensionIndex(char type) {

        int i = EXTENSION_TYPES.indexOf(type);

        if (i < 0)  throw new InternalError();

        return (byte) i;

    }

    /**

     * 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.

     */

    protected abstract SpeciesData speciesData();

    @Override

    final Object internalProperties() {

        return "/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);

    }

    public final Object arg(int i) {

        try {

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

            case 'L': return argL(i);

            case 'I': return argI(i);

            case 'F': return argF(i);

            case 'D': return argD(i);

            case 'J': return argJ(i);

            }

        } catch (Throwable ex) {

            throw newInternalError(ex);

        }

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

    }

    public final Object argL(int i) throws Throwable { return          speciesData().getters[i].invokeBasic(this); }

    public final int    argI(int i) throws Throwable { return (int)    speciesData().getters[i].invokeBasic(this); }

    public final float  argF(int i) throws Throwable { return (float)  speciesData().getters[i].invokeBasic(this); }

    public final double argD(int i) throws Throwable { return (double) speciesData().getters[i].invokeBasic(this); }

    public final long   argJ(int i) throws Throwable { return (long)   speciesData().getters[i].invokeBasic(this); }

    //

    // cloning API

    //

    public abstract BoundMethodHandle clone(MethodType mt, LambdaForm lf) throws Throwable;

    public abstract BoundMethodHandle cloneExtendL(MethodType mt, LambdaForm lf, Object narg) throws Throwable;

    public abstract BoundMethodHandle cloneExtendI(MethodType mt, LambdaForm lf, int    narg) throws Throwable;

    public abstract BoundMethodHandle cloneExtendJ(MethodType mt, LambdaForm lf, long   narg) throws Throwable;

    public abstract BoundMethodHandle cloneExtendF(MethodType mt, LambdaForm lf, float  narg) throws Throwable;

    public abstract BoundMethodHandle cloneExtendD(MethodType mt, LambdaForm lf, double narg) throws Throwable;

    // The following is a grossly irregular hack:

    @Override MethodHandle reinvokerTarget() {

        try {

            return (MethodHandle) argL(0);

        } catch (Throwable ex) {

            throw newInternalError(ex);

        }

    }

    //

    // 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;

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

            super(mt, lf);

            this.argL0 = argL0;

        }

        // The following is a grossly irregular hack:

        @Override MethodHandle reinvokerTarget() { return (MethodHandle) argL0; }

        @Override

        public SpeciesData speciesData() {

            return SPECIES_DATA;

        }

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

        @Override

        public final BoundMethodHandle clone(MethodType mt, LambdaForm lf) throws Throwable {

            return new Species_L(mt, lf, argL0);

        }

        @Override

        public final BoundMethodHandle cloneExtendL(MethodType mt, LambdaForm lf, Object narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_L).constructor[0].invokeBasic(mt, lf, argL0, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendI(MethodType mt, LambdaForm lf, int narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_I).constructor[0].invokeBasic(mt, lf, argL0, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendJ(MethodType mt, LambdaForm lf, long narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_J).constructor[0].invokeBasic(mt, lf, argL0, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendF(MethodType mt, LambdaForm lf, float narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_F).constructor[0].invokeBasic(mt, lf, argL0, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendD(MethodType mt, LambdaForm lf, double narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_D).constructor[0].invokeBasic(mt, lf, argL0, narg);

        }

    }

/*

    static final class Species_LL extends BoundMethodHandle {

        final Object argL0;

        final Object argL1;

        public Species_LL(MethodType mt, LambdaForm lf, Object argL0, Object argL1) {

            super(mt, lf);

            this.argL0 = argL0;

            this.argL1 = argL1;

        }

        @Override

        public SpeciesData speciesData() {

            return SPECIES_DATA;

        }

        public static final SpeciesData SPECIES_DATA = SpeciesData.getForClass("LL", Species_LL.class);

        @Override

        public final BoundMethodHandle clone(MethodType mt, LambdaForm lf) throws Throwable {

            return new Species_LL(mt, lf, argL0, argL1);

        }

        @Override

        public final BoundMethodHandle cloneExtendL(MethodType mt, LambdaForm lf, Object narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_L).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendI(MethodType mt, LambdaForm lf, int narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_I).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendJ(MethodType mt, LambdaForm lf, long narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_J).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendF(MethodType mt, LambdaForm lf, float narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_F).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendD(MethodType mt, LambdaForm lf, double narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_D).constructor[0].invokeBasic(mt, lf, argL0, argL1, narg);

        }

    }

    static final class Species_JL extends BoundMethodHandle {

        final long argJ0;

        final Object argL1;

        public Species_JL(MethodType mt, LambdaForm lf, long argJ0, Object argL1) {

            super(mt, lf);

            this.argJ0 = argJ0;

            this.argL1 = argL1;

        }

        @Override

        public SpeciesData speciesData() {

            return SPECIES_DATA;

        }

        public static final SpeciesData SPECIES_DATA = SpeciesData.getForClass("JL", Species_JL.class);

        @Override public final long   argJ0() { return argJ0; }

        @Override public final Object argL1() { return argL1; }

        @Override

        public final BoundMethodHandle clone(MethodType mt, LambdaForm lf) throws Throwable {

            return new Species_JL(mt, lf, argJ0, argL1);

        }

        @Override

        public final BoundMethodHandle cloneExtendL(MethodType mt, LambdaForm lf, Object narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_L).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendI(MethodType mt, LambdaForm lf, int narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_I).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendJ(MethodType mt, LambdaForm lf, long narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_J).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendF(MethodType mt, LambdaForm lf, float narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_F).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);

        }

        @Override

        public final BoundMethodHandle cloneExtendD(MethodType mt, LambdaForm lf, double narg) throws Throwable {

            return (BoundMethodHandle) SPECIES_DATA.extendWithIndex(INDEX_D).constructor[0].invokeBasic(mt, lf, argJ0, argL1, narg);

        }

    }

*/

    //

    // BMH species meta-data

    //

    /**

     * Meta-data wrapper for concrete BMH classes.

     */

    static class SpeciesData {

        final String                             types;

        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.

        final MethodHandle[]                     constructor;

        final MethodHandle[]                     getters;

        final SpeciesData[]                      extensions;

        public int fieldCount() {

            return types.length();

        }

        public char fieldType(int i) {

            return types.charAt(i);

        }

        public String toString() {

            return "SpeciesData["+(isPlaceholder() ? "<placeholder>" : clazz.getSimpleName())+":"+types+"]";

        }

        /**

         * 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.

         */

        Name getterName(Name mhName, int i) {

            MethodHandle mh = getters[i];

            assert(mh != null) : this+"."+i;

            return new Name(mh, mhName);

        }

        NamedFunction getterFunction(int i) {

            return new NamedFunction(getters[i]);

        }

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

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

            this.types = types;

            this.clazz = clazz;

            if (!INIT_DONE) {

                this.constructor = new MethodHandle[1];

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

            } else {

                throw new IllegalStateException("bound method handle");

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

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

            }

            this.extensions = new SpeciesData[EXTENSION_TYPES.length()];

        }

        private void initForBootstrap() {

            assert(!INIT_DONE);

            if (constructor[0] == null) {

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

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

            }

        }

        private SpeciesData(String types) {

            // Placeholder only.

            this.types = types;

            this.clazz = null;

            this.constructor = null;

            this.getters = 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 extendWithType(char type) {

            int i = extensionIndex(type);

            SpeciesData d = extensions[i];

            if (d != null)  return d;

            extensions[i] = d = get(types+type);

            return d;

        }

        SpeciesData extendWithIndex(byte index) {

            SpeciesData d = extensions[index];

            if (d != null)  return d;

            extensions[index] = d = get(types+EXTENSION_TYPES.charAt(index));

            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())

                    throw new IllegalStateException("Cannot generate anything");

            }

            // 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;

            SpeciesData d0 = BoundMethodHandle.SPECIES_DATA;  // trigger class init

            assert(d0 == null || d0 == lookupCache("")) : d0;

            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.types));

                    }

                }

                */

            } 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);

    }

    private static final Lookup LOOKUP = Lookup.IMPL_LOOKUP;

    /**

     * All subclasses must provide such a value describing their type signature.

     */

    static final SpeciesData SPECIES_DATA = SpeciesData.EMPTY;

}