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 * License Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
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 *
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package org.jruby.runtime.invokedynamic;

import java.lang.invoke.CallSite;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodType;
import java.lang.invoke.SwitchPoint;
import java.util.List;

import static java.lang.invoke.MethodHandles.*;
import static java.lang.invoke.MethodType.*;

import com.headius.invokebinder.Binder;
import org.jruby.Ruby;
import org.jruby.RubyClass;
import org.jruby.RubyFixnum;
import org.jruby.RubyFloat;
import org.jruby.RubyNumeric;
import org.jruby.runtime.CallType;
import org.jruby.runtime.MethodIndex;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.runtime.callsite.CacheEntry;
import org.jruby.util.JavaNameMangler;
import org.jruby.util.StringSupport;
import org.jruby.util.cli.Options;
import org.jruby.util.log.Logger;
import org.jruby.util.log.LoggerFactory;

public class MathLinker {

    private static final Logger LOG = LoggerFactory.getLogger(MathLinker.class);
    static { // enable DEBUG output
        if (Options.INVOKEDYNAMIC_LOG_BINDING.load()) LOG.setDebugEnable(true);
    }
    private static final boolean LOG_BINDING = LOG.isDebugEnabled();

    public static final MethodHandle FIXNUM_TEST =
            Binder
                    .from(methodType(boolean.class, IRubyObject.class))
                    .invokeStaticQuiet(lookup(), MathLinker.class, "fixnumTest");
    public static final MethodHandle FIXNUM_OPERATOR_FAIL =
            Binder
                    .from(methodType(IRubyObject.class, ThreadContext.class, IRubyObject.class, IRubyObject.class, JRubyCallSite.class, RubyFixnum.class))
                    .invokeStaticQuiet(lookup(), MathLinker.class, "fixnumOperatorFail");
    public static final MethodHandle FIXNUM_BOOLEAN_FAIL =
            Binder
                    .from(methodType(boolean.class, ThreadContext.class, IRubyObject.class, IRubyObject.class, JRubyCallSite.class, RubyFixnum.class))
                    .invokeStaticQuiet(lookup(), MathLinker.class, "fixnumBooleanFail");
    public static final MethodHandle FLOAT_TEST =
            Binder
                    .from(methodType(boolean.class, IRubyObject.class))
                    .invokeStaticQuiet(lookup(), MathLinker.class, "floatTest");
    public static final MethodHandle FLOAT_OPERATOR_FAIL =
            Binder
                    .from(methodType(IRubyObject.class, ThreadContext.class, IRubyObject.class, IRubyObject.class, JRubyCallSite.class, RubyFloat.class))
                    .invokeStaticQuiet(lookup(), MathLinker.class, "floatOperatorFail");
    public static final MethodHandle FIXNUM_OPERATOR =
            Binder
                    .from(methodType(IRubyObject.class, ThreadContext.class, IRubyObject.class, IRubyObject.class, JRubyCallSite.class, long.class))
                    .invokeStaticQuiet(lookup(), MathLinker.class, "fixnumOperator");
    public static final MethodHandle FIXNUM_BOOLEAN = Binder.from(methodType(boolean.class, ThreadContext.class, IRubyObject.class, IRubyObject.class, JRubyCallSite.class, long.class)).invokeStaticQuiet(lookup(), MathLinker.class, "fixnumBoolean");
    public static final MethodHandle FLOAT_OPERATOR = Binder.from(methodType(IRubyObject.class, ThreadContext.class, IRubyObject.class, IRubyObject.class, JRubyCallSite.class, double.class)).invokeStaticQuiet(lookup(), MathLinker.class, "floatOperator");

    private static final CallType[] CALL_TYPES = CallType.values();

    private static final int[] ARG_2_TO_0 = new int[] { 2 }; // MethodHandles.permuteArguments clones the array
    public static final MethodHandle FLOAT_TEST_ARG_2_TO_0 = permuteArguments(FLOAT_TEST, methodType(boolean.class, ThreadContext.class, IRubyObject.class, IRubyObject.class), ARG_2_TO_0);
    public static final MethodHandle FIXNUM_TEST_ARG_2_TO_0 = permuteArguments(FIXNUM_TEST, methodType(boolean.class, ThreadContext.class, IRubyObject.class, IRubyObject.class), ARG_2_TO_0);

    public static CallSite fixnumOperatorBootstrap(Lookup lookup, String name, MethodType type, long value, int callType, String file, int line) throws NoSuchMethodException, IllegalAccessException {
        List<String> names = StringSupport.split(name, ':');
        String operator = JavaNameMangler.demangleMethodName(names.get(1));
        JRubyCallSite site = new JRubyCallSite(lookup, type, CALL_TYPES[callType], file, line, operator);

        MethodHandle target = FIXNUM_OPERATOR;
        target = insertArguments(target, 3, site, value);

        site.setTarget(target);
        return site;
    }

    public static CallSite fixnumBooleanBootstrap(Lookup lookup, String name, MethodType type, long value, int callType, String file, int line) throws NoSuchMethodException, IllegalAccessException {
        List<String> names = StringSupport.split(name, ':');
        String operator = JavaNameMangler.demangleMethodName(names.get(1));
        JRubyCallSite site = new JRubyCallSite(lookup, type, CALL_TYPES[callType], file, line, operator);

        MethodHandle target = FIXNUM_BOOLEAN;
        target = insertArguments(target, 3, site, value);

        site.setTarget(target);
        return site;
    }

    public static CallSite floatOperatorBootstrap(Lookup lookup, String name, MethodType type, double value, int callType, String file, int line) throws NoSuchMethodException, IllegalAccessException {
        List<String> names = StringSupport.split(name, ':');
        String operator = JavaNameMangler.demangleMethodName(names.get(1));
        JRubyCallSite site = new JRubyCallSite(lookup, type, CALL_TYPES[callType], file, line, operator);

        MethodHandle target = FLOAT_OPERATOR;

        target = insertArguments(target, 3, site, value);

        site.setTarget(target);
        return site;
    }
    
    public static IRubyObject fixnumOperator(ThreadContext context, IRubyObject caller, IRubyObject self, JRubyCallSite site, long value) throws Throwable {
        Ruby runtime = context.runtime;
        String operator = site.name;

        MethodHandle target = null;

        MethodHandle fallback = insertArguments(FIXNUM_OPERATOR_FAIL, 3, site, runtime.newFixnum(value));

        CacheEntry entry = searchWithCache(operator, caller, self.getMetaClass(), site);

        if (!(self instanceof RubyFixnum) || entry == null || !entry.method.isBuiltin()) {
            site.setTarget(target = fallback); // invalid - fallback on slow-path

            if (LOG_BINDING) LOG.debug(site.name + "\tFixnum operation at site #" + site.siteID + " (" + site.file() + ":" + site.line() + ") bound indirectly");
        } else {
            String opMethod = MethodIndex.getFastFixnumOpsMethod(operator);
            String name = "fixnum_" + opMethod;

            if (operator.equals("+") || operator.equals("-")) {
                MethodType type = methodType(IRubyObject.class, ThreadContext.class, IRubyObject.class, IRubyObject.class);
                if (value == 1) {
                    name += "_one";
                    target = lookup().findStatic(MathLinker.class, name, type);
                } else if (value == 2) {
                    name += "_two";
                    target = lookup().findStatic(MathLinker.class, name, type);
                }
            }

            if (target == null) target = findTargetImpl(name, IRubyObject.class, value);

            RubyClass classFixnum = runtime.getFixnum();

            // confirm it's still a Fixnum
            target = guardWithTest(FIXNUM_TEST_ARG_2_TO_0, target, fallback);
            target = ((SwitchPoint) classFixnum.getInvalidator().getData()).guardWithTest(target, fallback);
            site.setTarget(target);

            if (LOG_BINDING) LOG.debug(name + "\tFixnum operation at site #" + site.siteID + " (" + site.file() + ":" + site.line() + ") bound directly");
        }
        
        return (IRubyObject) target.invokeWithArguments(context, caller, self);
    }
    
    public static boolean fixnumBoolean(ThreadContext context, IRubyObject caller, IRubyObject self, JRubyCallSite site, long value) throws Throwable {
        Ruby runtime = context.runtime;
        String operator = site.name;

        MethodHandle target;

        MethodHandle fallback = insertArguments(FIXNUM_BOOLEAN_FAIL, 3, site, runtime.newFixnum(value));

        CacheEntry entry = searchWithCache(operator, caller, self.getMetaClass(), site);

        if (!(self instanceof RubyFixnum) || entry == null || !entry.method.isBuiltin()) {
            site.setTarget(target = fallback); // invalid - fallback on slow-path

            if (LOG_BINDING) LOG.debug(site.name + "\tFixnum boolean operation at site #" + site.siteID + " (" + site.file() + ":" + site.line() + ") bound indirectly");
        } else {
            String opMethod = MethodIndex.getFastFixnumOpsMethod(operator);
            String name = "fixnum_boolean_" + opMethod;

            target = findTargetImpl(name, boolean.class, value);

            RubyClass classFixnum = runtime.getFixnum();

            // confirm it's still a Fixnum
            target = guardWithTest(FIXNUM_TEST_ARG_2_TO_0, target, fallback);
            target = ((SwitchPoint) classFixnum.getInvalidator().getData()).guardWithTest(target, fallback);
            site.setTarget(target);

            if (LOG_BINDING) LOG.debug(name + "\tFixnum boolean operation at site #" + site.siteID + " (" + site.file() + ":" + site.line() + ") bound directly");
        }
        
        return (Boolean) target.invokeWithArguments(context, caller, self);
    }

    static boolean fixnumTest(IRubyObject self) {
        return self instanceof RubyFixnum;
    }

    static IRubyObject fixnumOperatorFail(ThreadContext context, IRubyObject caller, IRubyObject self, JRubyCallSite site, RubyFixnum value) throws Throwable {
        return callMethod(context, caller, self, site, value);
    }

    static boolean fixnumBooleanFail(ThreadContext context, IRubyObject caller, IRubyObject self, JRubyCallSite site, RubyFixnum value) throws Throwable {
        return fixnumOperatorFail(context, caller, self, site, value).isTrue();
    }

    public static IRubyObject fixnum_op_plus(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_plus(context, value);
    }

    public static IRubyObject fixnum_op_minus(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_minus(context, value);
    }

    public static IRubyObject fixnum_op_mul(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_mul(context, value);
    }

    public static IRubyObject fixnum_op_mod(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_mod(context, value);
    }

    public static IRubyObject fixnum_op_div(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_div(context, value);
    }

    public static IRubyObject fixnum_op_equal(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_equal(context, value);
    }

    public static IRubyObject fixnum_op_lt(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_lt(context, value);
    }

    public static IRubyObject fixnum_op_le(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_le(context, value);
    }

    public static IRubyObject fixnum_op_gt(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_gt(context, value);
    }

    public static IRubyObject fixnum_op_ge(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_ge(context, value);
    }

    public static boolean fixnum_boolean_op_equal(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_equal_boolean(context, value);
    }

    public static boolean fixnum_boolean_op_lt(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_lt_boolean(context, value);
    }

    public static boolean fixnum_boolean_op_le(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_le_boolean(context, value);
    }

    public static boolean fixnum_boolean_op_gt(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_gt_boolean(context, value);
    }

    public static boolean fixnum_boolean_op_ge(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_ge_boolean(context, value);
    }

    public static IRubyObject fixnum_op_cmp(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_cmp(context, value);
    }

    public static IRubyObject fixnum_op_and(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_and(context, value);
    }

    public static IRubyObject fixnum_op_or(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_or(context, value);
    }

    public static IRubyObject fixnum_op_xor(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_xor(context, value);
    }

    public static IRubyObject fixnum_op_rshift(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_rshift(context, value);
    }

    public static IRubyObject fixnum_op_lshift(ThreadContext context, IRubyObject caller, IRubyObject self, long value) throws Throwable {
        return ((RubyFixnum)self).op_lshift(context, value);
    }

    public static IRubyObject fixnum_op_plus_one(ThreadContext context, IRubyObject caller, IRubyObject self) throws Throwable {
        return ((RubyFixnum)self).op_plus_one(context);
    }

    public static IRubyObject fixnum_op_minus_one(ThreadContext context, IRubyObject caller, IRubyObject self) throws Throwable {
        return ((RubyFixnum)self).op_minus_one(context);
    }

    public static IRubyObject fixnum_op_plus_two(ThreadContext context, IRubyObject caller, IRubyObject self) throws Throwable {
        return ((RubyFixnum)self).op_plus_two(context);
    }

    public static IRubyObject fixnum_op_minus_two(ThreadContext context, IRubyObject caller, IRubyObject self) throws Throwable {
        return ((RubyFixnum)self).op_minus_two(context);
    }
    
    public static IRubyObject floatOperator(ThreadContext context, IRubyObject caller, IRubyObject self, JRubyCallSite site, double value) throws Throwable {
        Ruby runtime = context.runtime;
        String operator = site.name;

        MethodHandle target;

        MethodHandle fallback = insertArguments(FLOAT_OPERATOR_FAIL, 3, site, RubyFloat.newFloat(runtime, value));

        CacheEntry entry = searchWithCache(operator, caller, self.getMetaClass(), site);

        if (!(self instanceof RubyFloat) || entry == null || !entry.method.isBuiltin()) {
            site.setTarget(target = fallback); // invalid - fallback on slow-path

            if (LOG_BINDING) LOG.debug(site.name + "\tFloat operation at site #" + site.siteID + " (" + site.file() + ":" + site.line() + ") bound indirectly");
        } else {
            String opMethod = MethodIndex.getFastFloatOpsMethod(operator);
            String name = "float_" + opMethod;

            target = findTargetImpl(name, IRubyObject.class, value);

            RubyClass classFloat = runtime.getFloat();

            // confirm it's still a Float
            target = guardWithTest(FLOAT_TEST_ARG_2_TO_0, target, fallback);
            target = ((SwitchPoint) classFloat.getInvalidator().getData()).guardWithTest(target, fallback);
            site.setTarget(target);

            if (LOG_BINDING) LOG.debug(name + "\tFloat operation at site #" + site.siteID + " (" + site.file() + ":" + site.line() + ") bound directly");
        }
        
        return (IRubyObject) target.invokeWithArguments(context, caller, self);
    }

    static boolean floatTest(IRubyObject self) {
        return self instanceof RubyFloat;
    }

    public static IRubyObject float_op_plus(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_plus(context, value);
    }

    public static IRubyObject float_op_minus(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_minus(context, value);
    }

    public static IRubyObject float_op_mul(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_mul(context, value);
    }

    public static IRubyObject float_op_mod(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_mod(context, value);
    }

    public static IRubyObject float_op_div(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_div(context, value);
    }

    public static IRubyObject float_op_equal(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_equal(context, value);
    }

    public static IRubyObject float_op_lt(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_lt(context, value);
    }

    public static IRubyObject float_op_le(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_le(context, value);
    }

    public static IRubyObject float_op_gt(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_gt(context, value);
    }

    public static IRubyObject float_op_ge(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_ge(context, value);
    }

    public static IRubyObject float_op_cmp(ThreadContext context, IRubyObject caller, IRubyObject self, double value) throws Throwable {
        return ((RubyFloat)self).op_cmp(context, value);
    }

    static IRubyObject floatOperatorFail(ThreadContext context, IRubyObject caller, IRubyObject self, JRubyCallSite site, RubyFloat value) throws Throwable {
        return callMethod(context, caller, self, site, value);
    }

    private static MethodHandle findTargetImpl(final String name, Class<?> returnType, final long value) throws NoSuchMethodException, IllegalAccessException {
        MethodType type = methodType(returnType, ThreadContext.class, IRubyObject.class, IRubyObject.class);
        type = type.insertParameterTypes(3, long.class);
        MethodHandle target = lookup().findStatic(MathLinker.class, name, type);
        return insertArguments(target, 3, value);
    }

    private static MethodHandle findTargetImpl(final String name, Class<?> returnType, final double value) throws NoSuchMethodException, IllegalAccessException {
        MethodType type = methodType(returnType, ThreadContext.class, IRubyObject.class, IRubyObject.class);
        type = type.insertParameterTypes(3, double.class);
        MethodHandle target = lookup().findStatic(MathLinker.class, name, type);
        return insertArguments(target, 3, value);
    }

    private static IRubyObject callMethod(ThreadContext context, IRubyObject caller, IRubyObject self, JRubyCallSite site, RubyNumeric value) {
        String operator = site.name;
        RubyClass selfClass = InvokeDynamicSupport.pollAndGetClass(context, self);
        CacheEntry entry = searchWithCache(operator, caller, selfClass, site);
        if (entry == null) { // method_missing
            return InvokeDynamicSupport.callMethodMissing(CacheEntry.NULL_CACHE, site.callType, context, self, operator, value);
        }
        return entry.method.call(context, self, entry.sourceModule, operator, value);
    }

    private static CacheEntry searchWithCache(final String operator, IRubyObject caller, RubyClass selfClass, JRubyCallSite site) {
        CacheEntry entry = site.entry;
        if (!entry.typeOk(selfClass)) {
            entry = selfClass.searchWithCache(operator);
            if (InvokeDynamicSupport.methodMissing(entry, site.callType, operator, caller)) {
                return null; // TODO rework method-missing
            }
            site.entry = entry;
        }
        return entry;
    }

}
