/*

 * Copyright 2008-2009 Sun Microsystems, Inc.  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.  Sun designates this

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

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.dyn;

import java.dyn.MethodHandle;

import java.dyn.MethodType;

import java.lang.reflect.AccessibleObject;

import java.lang.reflect.Field;

import static sun.dyn.MethodHandleNatives.Constants.*;

/**

 * The JVM interface for the method handles package is all here.

 * @author jrose

 */

class MethodHandleNatives {

    private MethodHandleNatives() { } // static only

    /// MethodName support

    static native void init(MemberName self, Object ref);

    static native void expand(MemberName self);

    static native void resolve(MemberName self, Class<?> caller);

    static native int getMembers(Class<?> defc, String matchName, String matchSig,

            int matchFlags, Class<?> caller, int skip, MemberName[] results);

    static Class<?> asNativeCaller(Class<?> lookupClass) {

        if (lookupClass == null)  // means "public only, non-privileged"

            return sun.dyn.empty.Empty.class;

        if (lookupClass == Access.class)  // means "internal, privileged"

            return null;    // to the JVM, null means completely privileged

        return lookupClass;

    }

    /// MethodHandle support

    /** Initialize the method handle to adapt the call. */

    static native void init(AdapterMethodHandle self, MethodHandle target, int argnum);

    /** Initialize the method handle to call the correct method, directly. */

    static native void init(BoundMethodHandle self, Object target, int argnum);

    /** Initialize the method handle to call as if by an invoke* instruction. */

    static native void init(DirectMethodHandle self, Object ref, boolean doDispatch, Class<?> caller);

    /** Initialize a method type, once per form. */

    static native void init(MethodType self);

    /** Tell the JVM that we need to change the target of an invokedynamic. */

    static native void linkCallSite(CallSiteImpl site, MethodHandle target);

    /** Fetch the vmtarget field.

     *  It will be sanitized as necessary to avoid exposing non-Java references.

     *  This routine is for debugging and reflection.

     */

    static native Object getTarget(MethodHandle self, int format);

    /** Fetch the name of the handled method, if available.

     *  This routine is for debugging and reflection.

     */

    static MemberName getMethodName(MethodHandle self) {

        if (!JVM_SUPPORT)  return null;

        return (MemberName) getTarget(self, ETF_METHOD_NAME);

    }

    /** Fetch the reflective version of the handled method, if available.

     */

    static AccessibleObject getTargetMethod(MethodHandle self) {

        if (!JVM_SUPPORT)  return null;

        return (AccessibleObject) getTarget(self, ETF_REFLECT_METHOD);

    }

    /** Fetch the target of this method handle.

     *  If it directly targets a method, return a tuple of method info.

     *  The info is of the form new Object[]{defclass, name, sig, refclass}.

     *  If it is chained to another method handle, return that handle.

     */

    static Object getTargetInfo(MethodHandle self) {

        if (!JVM_SUPPORT)  return null;

        return getTarget(self, ETF_HANDLE_OR_METHOD_NAME);

    }

    static Object[] makeTarget(Class<?> defc, String name, String sig, int mods, Class<?> refc) {

        return new Object[] { defc, name, sig, mods, refc };

    }

    /** Fetch MH-related JVM parameter.

     *  which=0 retrieves MethodHandlePushLimit

     *  which=1 retrieves stack slot push size (in address units)

     */

    static native int getConstant(int which);

    /** True iff this HotSpot JVM has built-in support for method handles.

     * If false, some test cases might run, but functionality will be missing.

     */

    public static final boolean JVM_SUPPORT;

    /** Java copy of MethodHandlePushLimit in range 2..255. */

    static final int JVM_PUSH_LIMIT;

    /** JVM stack motion (in words) after one slot is pushed, usually -1.

     */

    static final int JVM_STACK_MOVE_UNIT;

    private static native void registerNatives();

    static {

        boolean JVM_SUPPORT_;

        int     JVM_PUSH_LIMIT_;

        int     JVM_STACK_MOVE_UNIT_;

        try {

            registerNatives();

            JVM_SUPPORT_ = true;

            JVM_PUSH_LIMIT_ = getConstant(Constants.GC_JVM_PUSH_LIMIT);

            JVM_STACK_MOVE_UNIT_ = getConstant(Constants.GC_JVM_STACK_MOVE_LIMIT);

            //sun.reflect.Reflection.registerMethodsToFilter(MethodHandleImpl.class, "init");

        } catch (UnsatisfiedLinkError ee) {

            // ignore; if we use init() methods later we'll see linkage errors

            JVM_SUPPORT_ = false;

            JVM_PUSH_LIMIT_ = 3;  // arbitrary

            JVM_STACK_MOVE_UNIT_ = -1;  // arbitrary

            //System.out.println("Warning: Running with JVM_SUPPORT=false");

            //System.out.println(ee);

            JVM_SUPPORT = JVM_SUPPORT_;

            JVM_PUSH_LIMIT = JVM_PUSH_LIMIT_;

            JVM_STACK_MOVE_UNIT = JVM_STACK_MOVE_UNIT_;

            throw ee;  // just die; hopeless to try to run with an older JVM

        }

        JVM_SUPPORT = JVM_SUPPORT_;

        JVM_PUSH_LIMIT = JVM_PUSH_LIMIT_;

        JVM_STACK_MOVE_UNIT = JVM_STACK_MOVE_UNIT_;

    }

    // All compile-time constants go here.

    // There is an opportunity to check them against the JVM's idea of them.

    static class Constants {

        Constants() { } // static only

        // MethodHandleImpl

        static final int // for getConstant

                GC_JVM_PUSH_LIMIT = 0,

                GC_JVM_STACK_MOVE_LIMIT = 1;

        static final int

                ETF_HANDLE_OR_METHOD_NAME = 0, // all available data (immediate MH or method)

                ETF_DIRECT_HANDLE         = 1, // ultimate method handle (will be a DMH, may be self)

                ETF_METHOD_NAME           = 2, // ultimate method as MemberName

                ETF_REFLECT_METHOD        = 3; // ultimate method as java.lang.reflect object (sans refClass)

        // MemberName

        // The JVM uses values of -2 and above for vtable indexes.

        // Field values are simple positive offsets.

        // Ref: src/share/vm/oops/methodOop.hpp

        // This value is negative enough to avoid such numbers,

        // but not too negative.

        static final int

                MN_IS_METHOD           = 0x00010000, // method (not constructor)

                MN_IS_CONSTRUCTOR      = 0x00020000, // constructor

                MN_IS_FIELD            = 0x00040000, // field

                MN_IS_TYPE             = 0x00080000, // nested type

                MN_SEARCH_SUPERCLASSES = 0x00100000, // for MHN.getMembers

                MN_SEARCH_INTERFACES   = 0x00200000, // for MHN.getMembers

                VM_INDEX_UNINITIALIZED = -99;

        // AdapterMethodHandle

        /** Conversions recognized by the JVM.

         *  They must align with the constants in sun.dyn_AdapterMethodHandle,

         *  in the JVM file hotspot/src/share/vm/classfile/javaClasses.hpp.

         */

        static final int

            OP_RETYPE_ONLY   = 0x0, // no argument changes; straight retype

            OP_CHECK_CAST    = 0x1, // ref-to-ref conversion; requires a Class argument

            OP_PRIM_TO_PRIM  = 0x2, // converts from one primitive to another

            OP_REF_TO_PRIM   = 0x3, // unboxes a wrapper to produce a primitive

            OP_PRIM_TO_REF   = 0x4, // boxes a primitive into a wrapper (NYI)

            OP_SWAP_ARGS     = 0x5, // swap arguments (vminfo is 2nd arg)

            OP_ROT_ARGS      = 0x6, // rotate arguments (vminfo is displaced arg)

            OP_DUP_ARGS      = 0x7, // duplicates one or more arguments (at TOS)

            OP_DROP_ARGS     = 0x8, // remove one or more argument slots

            OP_COLLECT_ARGS  = 0x9, // combine one or more arguments into a varargs (NYI)

            OP_SPREAD_ARGS   = 0xA, // expand in place a varargs array (of known size)

            OP_FLYBY         = 0xB, // operate first on reified argument list (NYI)

            OP_RICOCHET      = 0xC, // run an adapter chain on the return value (NYI)

            CONV_OP_LIMIT    = 0xD; // limit of CONV_OP enumeration

        /** Shift and mask values for decoding the AMH.conversion field.

         *  These numbers are shared with the JVM for creating AMHs.

         */

        static final int

            CONV_OP_MASK     = 0xF00, // this nybble contains the conversion op field

            CONV_VMINFO_MASK = 0x0FF, // LSB is reserved for JVM use

            CONV_VMINFO_SHIFT     =  0, // position of bits in CONV_VMINFO_MASK

            CONV_OP_SHIFT         =  8, // position of bits in CONV_OP_MASK

            CONV_DEST_TYPE_SHIFT  = 12, // byte 2 has the adapter BasicType (if needed)

            CONV_SRC_TYPE_SHIFT   = 16, // byte 2 has the source BasicType (if needed)

            CONV_STACK_MOVE_SHIFT = 20, // high 12 bits give signed SP change

            CONV_STACK_MOVE_MASK  = (1 << (32 - CONV_STACK_MOVE_SHIFT)) - 1;

        /** Which conv-ops are implemented by the JVM? */

        static final int CONV_OP_IMPLEMENTED_MASK =

                // TODO: The following expression should be replaced by

                // a JVM query.

                ((1<<OP_RETYPE_ONLY)

                |(1<<OP_CHECK_CAST)

                |(1<<OP_PRIM_TO_PRIM)

                |(1<<OP_REF_TO_PRIM)

                |(1<<OP_SWAP_ARGS)

                |(1<<OP_ROT_ARGS)

                |(1<<OP_DUP_ARGS)

                |(1<<OP_DROP_ARGS)

                );

        /**

         * Basic types as encoded in the JVM.  These code values are not

         * intended for use outside this class.  They are used as part of

         * a private interface between the JVM and this class.

         */

        static final int

            T_BOOLEAN  =  4,

            T_CHAR     =  5,

            T_FLOAT    =  6,

            T_DOUBLE   =  7,

            T_BYTE     =  8,

            T_SHORT    =  9,

            T_INT      = 10,

            T_LONG     = 11,

            T_OBJECT   = 12,

            //T_ARRAY    = 13

            T_VOID     = 14;

            //T_ADDRESS  = 15

    }

    private static native int getNamedCon(int which, Object[] name);

    static boolean verifyConstants() {

        Object[] box = { null };

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

            box[0] = null;

            int vmval = getNamedCon(i, box);

            if (box[0] == null)  break;

            String name = (String) box[0];

            try {

                Field con = Constants.class.getDeclaredField(name);

                int jval = con.getInt(null);

                if (jval != vmval)

                    throw new InternalError(name+": JVM has "+vmval+" while Java has "+jval);

            } catch (Exception ex) {

                throw new InternalError(name+": access failed, got "+ex);

            }

        }

        return true;

    }

    static {

        if (JVM_SUPPORT)  verifyConstants();

    }

}