/*

 * Copyright (c) 2008, 2011, 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 sun.invoke.util.ValueConversions;

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationTargetException;

import java.util.ArrayList;

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

import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;

/**

 * Generic spread adapter.

 * Expands a final argument into multiple (zero or more) arguments, keeping the others the same.

 * @author jrose

 */

class SpreadGeneric {

    // type for the outgoing call

    private final MethodType targetType;

    // number of arguments to spread

    private final int spreadCount;

    // prototype adapter (clone and customize for each new target!)

    private final Adapter adapter;

    // entry point for adapter (Adapter mh, a...) => ...

    private final MethodHandle entryPoint;

    /** Compute and cache information common to all spreading adapters

     *  that accept calls of the given (generic) type.

     */

    private SpreadGeneric(MethodType targetType, int spreadCount) {

        assert(targetType == targetType.generic());

        this.targetType = targetType;

        this.spreadCount = spreadCount;

        // the target invoker will generally need casts on reference arguments

        MethodHandle[] ep = { null };

        Adapter ad = findAdapter(this, ep);

        if (ad != null) {

            this.adapter = ad;

            this.entryPoint = ep[0];

            return;

        }

        this.adapter = buildAdapterFromBytecodes(targetType, spreadCount, ep);

        this.entryPoint = ep[0];

    }

    static {

        assert(MethodHandleNatives.workaroundWithoutRicochetFrames());  // this class is deprecated

    }

    /** From targetType remove the last spreadCount arguments, and instead

     *  append a simple Object argument.

     */

    static MethodType preSpreadType(MethodType targetType, int spreadCount) {

        @SuppressWarnings("unchecked")

        ArrayList<Class<?>> params = new ArrayList(targetType.parameterList());

        int outargs = params.size();

        params.subList(outargs - spreadCount, outargs).clear();

        params.add(Object.class);

        return MethodType.methodType(targetType.returnType(), params);

    }

    MethodHandle makeInstance(MethodHandle target) {

        MethodType type = target.type();

        if (type != targetType) {

            throw new UnsupportedOperationException("NYI type="+type);

        }

        return adapter.makeInstance(this, target);

    }

    /** Build an adapter of the given generic type, which invokes typedTarget

     *  on the incoming arguments, after unboxing as necessary.

     *  The return value is boxed if necessary.

     * @param genericType  the required type of the result

     * @param typedTarget the target

     * @return an adapter method handle

     */

    public static MethodHandle make(MethodHandle target, int spreadCount) {

        MethodType type = target.type();

        MethodType gtype = type.generic();

        if (type == gtype) {

            return SpreadGeneric.of(type, spreadCount).makeInstance(target);

        } else {

            MethodHandle gtarget = FromGeneric.make(target);

            assert(gtarget.type() == gtype);

            MethodHandle gspread = SpreadGeneric.of(gtype, spreadCount).makeInstance(gtarget);

            return ToGeneric.make(preSpreadType(type, spreadCount), gspread);

        }

    }

    /** Return the adapter information for this type's erasure. */

    static SpreadGeneric of(MethodType targetType, int spreadCount) {

        if (targetType != targetType.generic())

            throw new UnsupportedOperationException("NYI type="+targetType);

        MethodTypeForm form = targetType.form();

        int outcount = form.parameterCount();

        assert(spreadCount <= outcount);

        SpreadGeneric[] spreadGens = form.spreadGeneric;

        if (spreadGens == null)

            form.spreadGeneric = spreadGens = new SpreadGeneric[outcount+1];

        SpreadGeneric spreadGen = spreadGens[spreadCount];

        if (spreadGen == null)

            spreadGens[spreadCount] = spreadGen = new SpreadGeneric(form.erasedType(), spreadCount);

        return spreadGen;

    }

    public String toString() {

        return getClass().getSimpleName()+targetType+"["+spreadCount+"]";

    }

    // This mini-api is called from an Adapter to manage the spread.

    /** A check/coercion that happens once before any selections. */

    protected Object check(Object av, int n) {

        checkSpreadArgument(av, n);

        return av;

    }

    /** The selection operator for spreading; note that it takes Object not Object[]. */

    protected Object select(Object av, int n) {

        return ((Object[])av)[n];

    }

    /*

    protected int select_I(Object av, int n) {

        // maybe return ((int[])select)[n]

        throw new UnsupportedOperationException("subclass resp.");

    }

    protected int select_J(Object av, int n) {

        // maybe return ((long[])select)[n]

        throw new UnsupportedOperationException("subclass resp.");

    }

    // */

    /* Create an adapter that handles spreading calls for the given type. */

    static Adapter findAdapter(SpreadGeneric outer, MethodHandle[] ep) {

        MethodType targetType = outer.targetType;

        int spreadCount = outer.spreadCount;

        int outargs = targetType.parameterCount();

        int inargs = outargs - spreadCount;

        if (inargs < 0)  return null;

        MethodType entryType = MethodType.genericMethodType(inargs + 1); // 1 for av

        String cname1 = "S" + outargs;

        String[] cnames = { cname1 };

        String iname = "invoke_S"+spreadCount;

        // e.g., D5I2, D5, L5I2, L5; invoke_D5

        for (String cname : cnames) {

            Class<? extends Adapter> acls = Adapter.findSubClass(cname);

            if (acls == null)  continue;

            // see if it has the required invoke method

            MethodHandle entryPoint = null;

            try {

                entryPoint = IMPL_LOOKUP.findSpecial(acls, iname, entryType, acls);

            } catch (ReflectiveOperationException ex) {

            }

            if (entryPoint == null)  continue;

            Constructor<? extends Adapter> ctor = null;

            try {

                ctor = acls.getDeclaredConstructor(SpreadGeneric.class);

            } catch (NoSuchMethodException ex) {

            } catch (SecurityException ex) {

            }

            if (ctor == null)  continue;

            try {

                // Produce an instance configured as a prototype.

                Adapter ad = ctor.newInstance(outer);

                ep[0] = entryPoint;

                return ad;

            } catch (IllegalArgumentException ex) {

            } catch (InvocationTargetException wex) {

                Throwable ex = wex.getTargetException();

                if (ex instanceof Error)  throw (Error)ex;

                if (ex instanceof RuntimeException)  throw (RuntimeException)ex;

            } catch (InstantiationException ex) {

            } catch (IllegalAccessException ex) {

            }

        }

        return null;

    }

    static Adapter buildAdapterFromBytecodes(MethodType targetType,

            int spreadCount, MethodHandle[] ep) {

        throw new UnsupportedOperationException("NYI");

    }

    /**

     * This adapter takes some untyped arguments, and returns an untyped result.

     * Internally, it applies the invoker to the target, which causes the

     * objects to be unboxed; the result is a raw type in L/I/J/F/D.

     * This result is passed to convert, which is responsible for

     * converting the raw result into a boxed object.

     * The invoker is kept separate from the target because it can be

     * generated once per type erasure family, and reused across adapters.

     */

    static abstract class Adapter extends BoundMethodHandle {

        /*

         * class X<<R,int M,int N>> extends Adapter {

         *   (Object**N)=>R target;

         *   static int S = N-M;

         *   Object invoke(Object**M a, Object v) = target(a..., v[0]...v[S-1]);

         * }

         */

        protected final SpreadGeneric outer;

        protected final MethodHandle target;   // (any**N) => R

        @Override

        public String toString() {

            return addTypeString(target, this);

        }

        static final MethodHandle NO_ENTRY = ValueConversions.identity();

        protected boolean isPrototype() { return target == null; }

        protected Adapter(SpreadGeneric outer) {

            super(NO_ENTRY);

            this.outer = outer;

            this.target = null;

            assert(isPrototype());

        }

        protected Adapter(SpreadGeneric outer, MethodHandle target) {

            super(outer.entryPoint);

            this.outer = outer;

            this.target = target;

        }

        /** Make a copy of self, with new fields. */

        protected abstract Adapter makeInstance(SpreadGeneric outer, MethodHandle target);

        // { return new ThisType(outer, target); }

        protected Object check(Object av, int n) {

            return outer.check(av, n);

        }

        protected Object select(Object av, int n) {

            return outer.select(av, n);

        }

        static private final String CLASS_PREFIX; // "java.lang.invoke.SpreadGeneric$"

        static {

            String aname = Adapter.class.getName();

            String sname = Adapter.class.getSimpleName();

            if (!aname.endsWith(sname))  throw new InternalError();

            CLASS_PREFIX = aname.substring(0, aname.length() - sname.length());

        }

        /** Find a sibing class of Adapter. */

        static Class<? extends Adapter> findSubClass(String name) {

            String cname = Adapter.CLASS_PREFIX + name;

            try {

                return Class.forName(cname).asSubclass(Adapter.class);

            } catch (ClassNotFoundException ex) {

                return null;

            } catch (ClassCastException ex) {

                return null;

            }

        }

    }

    /* generated classes follow this pattern:

    static class xS2 extends Adapter {

        protected xS2(SpreadGeneric outer) { super(outer); }  // to build prototype

        protected xS2(SpreadGeneric outer, MethodHandle t) { super(outer, t); }

        protected xS2 makeInstance(SpreadGeneric outer, MethodHandle t) { return new xS2(outer, t); }

        protected Object invoke_S0(Object a0, Object a1, Object av) throws Throwable { av = super.check(av,0);

             return target.invokeExact(a0, a1)); }

        protected Object invoke_S1(Object a0, Object av) throws Throwable { av = super.check(av,1);

             return target.invokeExact(a0,

                super.select(av,0)); }

        protected Object invoke_S2(Object a0, Object av) throws Throwable { av = super.check(av,1);

             return target.invokeExact(

                super.select(av,0), super.select(av,1)); }

    }

    // */

/*

: SHELL; n=SpreadGeneric; cp -p $n.java $n.java-; sed < $n.java- > $n.java+ -e '/{{*{{/,/}}*}}/w /tmp/genclasses.java' -e '/}}*}}/q'; (cd /tmp; javac -d . genclasses.java; java -cp . genclasses) >> $n.java+; echo '}' >> $n.java+; mv $n.java+ $n.java; mv $n.java- $n.java~

//{{{

import java.util.*;

class genclasses {

    static String[][] TEMPLATES = { {

        "@for@ N=0..10",

        "    //@each-cat@",

        "    static class @cat@ extends Adapter {",

        "        protected @cat@(SpreadGeneric outer) { super(outer); }  // to build prototype",

        "        protected @cat@(SpreadGeneric outer, MethodHandle t) { super(outer, t); }",

        "        protected @cat@ makeInstance(SpreadGeneric outer, MethodHandle t) { return new @cat@(outer, t); }",

        "        protected Object invoke_S0(@Tvav,@Object av) throws Throwable { av = super.check(av, 0);",

        "            return target.invokeExact(@av@); }",

        "        //@each-S@",

        "        protected Object invoke_S@S@(@Tvav,@Object av) throws Throwable { av = super.check(av, @S@);",

        "            return target.invokeExact(@av,@@sv@); }",

        "        //@end-S@",

        "    }",

    } };

    static final String NEWLINE_INDENT = "\n                ";

    enum VAR {

        cat, N, S, av, av_, Tvav_, sv;

        public final String pattern = "@"+toString().replace('_','.')+"@";

        public String binding = toString();

        static void makeBindings(boolean topLevel, int outargs, int spread) {

            int inargs = outargs - spread;

            VAR.cat.binding = "S"+outargs;

            VAR.N.binding = String.valueOf(outargs); // outgoing arg count

            VAR.S.binding = String.valueOf(spread);  // spread count

            String[] av = new String[inargs];

            String[] Tvav = new String[inargs];

            for (int i = 0; i < inargs; i++) {

                av[i] = arg(i);

                Tvav[i] = param("Object", av[i]);

            }

            VAR.av.binding = comma(av);

            VAR.av_.binding = comma(av, ", ");

            VAR.Tvav_.binding = comma(Tvav, ", ");

            String[] sv = new String[spread];

            for (int i = 0; i < spread; i++) {

                String spc = "";

                if (i % 4 == 0) spc = NEWLINE_INDENT;

                sv[i] = spc+"super.select(av,"+i+")";

            }

            VAR.sv.binding = comma(sv);

        }

        static String arg(int i) { return "a"+i; }

        static String param(String t, String a) { return t+" "+a; }

        static String comma(String[] v) { return comma(v, ""); }

        static String comma(String[] v, String sep) {

            if (v.length == 0)  return "";

            String res = v[0];

            for (int i = 1; i < v.length; i++)  res += ", "+v[i];

            return res + sep;

        }

        static String transform(String string) {

            for (VAR var : values())

                string = string.replaceAll(var.pattern, var.binding);

            return string;

        }

    }

    static String[] stringsIn(String[] strings, int beg, int end) {

        return Arrays.copyOfRange(strings, beg, Math.min(end, strings.length));

    }

    static String[] stringsBefore(String[] strings, int pos) {

        return stringsIn(strings, 0, pos);

    }

    static String[] stringsAfter(String[] strings, int pos) {

        return stringsIn(strings, pos, strings.length);

    }

    static int indexAfter(String[] strings, int pos, String tag) {

        return Math.min(indexBefore(strings, pos, tag) + 1, strings.length);

    }

    static int indexBefore(String[] strings, int pos, String tag) {

        for (int i = pos, end = strings.length; ; i++) {

            if (i == end || strings[i].endsWith(tag))  return i;

        }

    }

    static int MIN_ARITY, MAX_ARITY;

    public static void main(String... av) {

        for (String[] template : TEMPLATES) {

            int forLinesLimit = indexBefore(template, 0, "@each-cat@");

            String[] forLines = stringsBefore(template, forLinesLimit);

            template = stringsAfter(template, forLinesLimit);

            for (String forLine : forLines)

                expandTemplate(forLine, template);

        }

    }

    static void expandTemplate(String forLine, String[] template) {

        String[] params = forLine.split("[^0-9]+");

        if (params[0].length() == 0)  params = stringsAfter(params, 1);

        System.out.println("//params="+Arrays.asList(params));

        int pcur = 0;

        MIN_ARITY = Integer.valueOf(params[pcur++]);

        MAX_ARITY = Integer.valueOf(params[pcur++]);

        if (pcur != params.length)  throw new RuntimeException("bad extra param: "+forLine);

        for (int outargs = MIN_ARITY; outargs <= MAX_ARITY; outargs++) {

            expandTemplate(template, true, outargs, 0);

        }

    }

    static void expandTemplate(String[] template, boolean topLevel, int outargs, int spread) {

        VAR.makeBindings(topLevel, outargs, spread);

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

            String line = template[i];

            if (line.endsWith("@each-cat@")) {

                // ignore

            } else if (line.endsWith("@each-S@")) {

                int blockEnd = indexAfter(template, i, "@end-S@");

                String[] block = stringsIn(template, i+1, blockEnd-1);

                for (int spread1 = spread+1; spread1 <= outargs; spread1++)

                    expandTemplate(block, false, outargs, spread1);

                VAR.makeBindings(topLevel, outargs, spread);

                i = blockEnd-1; continue;

            } else {

                System.out.println(VAR.transform(line));

            }

        }

    }

}

//}}} */

//params=[0, 10]

    static class S0 extends Adapter {

        protected S0(SpreadGeneric outer) { super(outer); }  // to build prototype

        protected S0(SpreadGeneric outer, MethodHandle t) { super(outer, t); }

        protected S0 makeInstance(SpreadGeneric outer, MethodHandle t) { return new S0(outer, t); }

        protected Object invoke_S0(Object av) throws Throwable { av = super.check(av, 0);

            return target.invokeExact(); }

    }

    static class S1 extends Adapter {

        protected S1(SpreadGeneric outer) { super(outer); }  // to build prototype

        protected S1(SpreadGeneric outer, MethodHandle t) { super(outer, t); }

        protected S1 makeInstance(SpreadGeneric outer, MethodHandle t) { return new S1(outer, t); }

        protected Object invoke_S0(Object a0, Object av) throws Throwable { av = super.check(av, 0);

            return target.invokeExact(a0); }

        protected Object invoke_S1(Object av) throws Throwable { av = super.check(av, 1);

            return target.invokeExact(

                super.select(av,0)); }

    }

    static class S2 extends Adapter {

        protected S2(SpreadGeneric outer) { super(outer); }  // to build prototype

        protected S2(SpreadGeneric outer, MethodHandle t) { super(outer, t); }

        protected S2 makeInstance(SpreadGeneric outer, MethodHandle t) { return new S2(outer, t); }

        protected Object invoke_S0(Object a0, Object a1, Object av) throws Throwable { av = super.check(av, 0);

            return target.invokeExact(a0, a1); }

        protected Object invoke_S1(Object a0, Object av) throws Throwable { av = super.check(av, 1);

            return target.invokeExact(a0,

                super.select(av,0)); }

        protected Object invoke_S2(Object av) throws Throwable { av = super.check(av, 2);

            return target.invokeExact(

                super.select(av,0), super.select(av,1)); }

    }

    static class S3 extends Adapter {

        protected S3(SpreadGeneric outer) { super(outer); }  // to build prototype

        protected S3(SpreadGeneric outer, MethodHandle t) { super(outer, t); }

        protected S3 makeInstance(SpreadGeneric outer, MethodHandle t) { return new S3(outer, t); }

        protected Object invoke_S0(Object a0, Object a1, Object a2, Object av) throws Throwable { av = super.check(av, 0);

            return target.invokeExact(a0, a1, a2); }

        protected Object invoke_S1(Object a0, Object a1, Object av) throws Throwable { av = super.check(av, 1);

            return target.invokeExact(a0, a1,

                super.select(av,0)); }

        protected Object invoke_S2(Object a0, Object av) throws Throwable { av = super.check(av, 2);

            return target.invokeExact(a0,

                super.select(av,0), super.select(av,1)); }

        protected Object invoke_S3(Object av) throws Throwable { av = super.check(av, 3);

            return target.invokeExact(

                super.select(av,0), super.select(av,1), super.select(av,2)); }

    }

    static class S4 extends Adapter {

        protected S4(SpreadGeneric outer) { super(outer); }  // to build prototype

        protected S4(SpreadGeneric outer, MethodHandle t) { super(outer, t); }

        protected S4 makeInstance(SpreadGeneric outer, MethodHandle t) { return new S4(outer, t); }

        protected Object invoke_S0(Object a0, Object a1, Object a2, Object a3, Object av) throws Throwable { av = super.check(av, 0);

            return target.invokeExact(a0, a1, a2, a3); }

        protected Object invoke_S1(Object a0, Object a1, Object a2, Object av) throws Throwable { av = super.check(av, 1);

            return target.invokeExact(a0, a1, a2,

                super.select(av,0)); }

        protected Object invoke_S2(Object a0, Object a1, Object av) throws Throwable { av = super.check(av, 2);

            return target.invokeExact(a0, a1,

                super.select(av,0), super.select(av,1)); }

        protected Object invoke_S3(Object a0, Object av) throws Throwable { av = super.check(av, 3);

            return target.invokeExact(a0,

                super.select(av,0), super.select(av,1), super.select(av,2)); }

        protected Object invoke_S4(Object av) throws Throwable { av = super.check(av, 4);

            return target.invokeExact(

                super.select(av,0), super.select(av,1), super.select(av,2), super.select(av,3)); }

    }

    static class S5 extends Adapter {

        protected S5(SpreadGeneric outer) { super(outer); }  // to build prototype

        protected S5(SpreadGeneric outer, MethodHandle t) { super(outer, t); }

        protected S5 makeInstance(SpreadGeneric outer, MethodHandle t) { return new S5(outer, t); }

        protected Object invoke_S0(Object a0, Object a1, Object a2, Object a3, Object a4, Object av) throws Throwable { av = super.check(av, 0);

            return target.invokeExact(a0, a1, a2, a3, a4); }

        protected Object invoke_S1(Object a0, Object a1, Object a2, Object a3, Object av) throws Throwable { av = super.check(av, 1);

            return target.invokeExact(a0, a1, a2, a3,

                super.select(av,0)); }

        protected Object invoke_S2(Object a0, Object a1, Object a2, Object av) throws Throwable { av = super.check(av, 2);

            return target.invokeExact(a0, a1, a2,

                super.select(av,0), super.select(av,1)); }

        protected Object invoke_S3(Object a0, Object a1, Object av) throws Throwable { av = super.check(av, 3);

            return target.invokeExact(a0, a1,

                super.select(av,0), super.select(av,1), super.select(av,2)); }

        protected Object invoke_S4(Object a0, Object av) throws Throwable { av = super.check(av, 4);

            return target.invokeExact(a0,

                super.select(av,0), super.select(av,1), super.select(av,2), super.select(av,3)); }

        protected Object invoke_S5(Object av) throws Throwable { av = super.check(av, 5);

            return target.invokeExact(

                super.select(av,0), super.select(av,1), super.select(av,2), super.select(av,3),

                super.select(av,4)); }

    }

    static class S6 extends Adapter {

        protected S6(SpreadGeneric outer) { super(outer); }  // to build prototype

        protected S6(SpreadGeneric outer, MethodHandle t) { super(outer, t); }

        protected S6 makeInstance(SpreadGeneric outer, MethodHandle t) { return new S6(outer, t); }

        protected Object invoke_S0(Object a0, Object a1, Object a2, Object a3, Object a4, Object a5, Object av) throws Throwable { av = super.check(av, 0);

            return target.invokeExact(a0, a1, a2, a3, a4, a5); }

        protected Object invoke_S1(Object a0, Object a1, Object a2, Object a3, Object a4, Object av) throws Throwable { av = super.check(av, 1);

            return target.invokeExact(a0, a1, a2, a3, a4,

                super.select(av,0)); }

        protected Object invoke_S2(Object a0, Object a1, Object a2, Object a3, Object av) throws Throwable { av = super.check(av, 2);

            return target.invokeExact(a0, a1, a2, a3,

                super.select(av,0), super.select(av,1)); }

        protected Object invoke_S3(Object a0, Object a1, Object a2, Object av) throws Throwable { av = super.check(av, 3);

            return target.invokeExact(a0, a1, a2,

                super.select(av,0), super.select(av,1), super.select(av,2)); }

        protected Object invoke_S4(Object a0, Object a1, Object av) throws Throwable { av = super.check(av, 4);