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package org.jruby.runtime.invokedynamic;

import com.headius.invokebinder.Signature;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.invoke.MethodType;
import java.lang.invoke.MutableCallSite;
import java.util.concurrent.atomic.AtomicLong;

import org.jruby.RubyClass;
import org.jruby.runtime.Block;

import org.jruby.runtime.CallType;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.runtime.callsite.CacheEntry;

public class JRubyCallSite extends MutableCallSite {

    private static final AtomicLong SITE_ID = new AtomicLong(1);

    final long siteID = SITE_ID.getAndIncrement();
    final CallType callType;
    final String name;
    private final String file;
    private final int line;
    private final Signature signature;
    private final Signature fullSignature;
    private final int arity;

    CacheEntry entry = CacheEntry.NULL_CACHE;

    JRubyCallSite(Lookup lookup, MethodType type, CallType callType, String file, int line, String name) {
        super(type);

        this.name = name;
        this.callType = callType;

        Signature startSig;
        int argOffset;

        if (callType == CallType.SUPER) {
            // super calls receive current class argument, so offsets and signature are different
            startSig = JRubyCallSite.STANDARD_SUPER_SIG;
            argOffset = 4;
        } else {
            startSig = JRubyCallSite.STANDARD_SITE_SIG;
            argOffset = 3;
        }

        int arity;
        if (type.parameterType(type.parameterCount() - 1) == Block.class) {
            arity = type.parameterCount() - (argOffset + 1);

            if (arity == 1 && type.parameterType(argOffset) == IRubyObject[].class) {
                arity = -1;
                startSig = startSig.appendArg("args", IRubyObject[].class);
            } else {
                for (int i = 0; i < arity; i++) {
                    startSig = startSig.appendArg("arg" + i, IRubyObject.class);
                }
            }
            startSig = startSig.appendArg("block", Block.class);
            fullSignature = signature = startSig;
        } else {
            arity = type.parameterCount() - argOffset;

            if (arity == 1 && type.parameterType(argOffset) == IRubyObject[].class) {
                arity = -1;
                startSig = startSig.appendArg("args", IRubyObject[].class);
            } else {
                for (int i = 0; i < arity; i++) {
                    startSig = startSig.appendArg("arg" + i, IRubyObject.class);
                }
            }
            signature = startSig;
            fullSignature = startSig.appendArg("block", Block.class);
        }

        this.arity = arity;

        this.file = file;
        this.line = line;
    }

    public int arity() {
        return arity;
    }

    public CallType callType() {
        return callType;
    }

    public String file() {
        return file;
    }

    public int line() {
        return line;
    }

    public void setInitialTarget(MethodHandle target) {
        super.setTarget(target);
    }

    
Get the actual incoming Signature for this call site.
This represents the actual argument list.
Returns:
the actual Signature at the call site/**
     * Get the actual incoming Signature for this call site.
     * 
     * This represents the actual argument list.
     * 
     * @return the actual Signature at the call site
     */
    public Signature signature() {
        return signature;
    }
    
    
Get the "full" signature equivalent to this call site.
The "full" signature always guarantees context, caller, and block args
are provided. It could also be considered the standard intermediate
signature all calls eventually pass through.
Returns:
the "full" intermediate signature/**
     * Get the "full" signature equivalent to this call site.
     * 
     * The "full" signature always guarantees context, caller, and block args
     * are provided. It could also be considered the standard intermediate
     * signature all calls eventually pass through.
     * 
     * @return the "full" intermediate signature
     */
    public Signature fullSignature() {
        return fullSignature;
    }
    
    public static final Signature STANDARD_SITE_SIG = Signature
            .returning(IRubyObject.class)
            .appendArg("context", ThreadContext.class)
            .appendArg("caller", IRubyObject.class)
            .appendArg("self", IRubyObject.class);
    public static final Signature STANDARD_SITE_SIG_1ARG = STANDARD_SITE_SIG.appendArg("arg0", IRubyObject.class);
    public static final Signature STANDARD_SITE_SIG_2ARG = STANDARD_SITE_SIG_1ARG.appendArg("arg1", IRubyObject.class);
    public static final Signature STANDARD_SITE_SIG_3ARG = STANDARD_SITE_SIG_2ARG.appendArg("arg2", IRubyObject.class);
    public static final Signature STANDARD_SITE_SIG_NARG = STANDARD_SITE_SIG.appendArg("args", IRubyObject[].class);
    
    public static final Signature[] STANDARD_SITE_SIGS = {
        STANDARD_SITE_SIG,
        STANDARD_SITE_SIG_1ARG,
        STANDARD_SITE_SIG_2ARG,
        STANDARD_SITE_SIG_3ARG,
        STANDARD_SITE_SIG_NARG,
    };
    
    public static final Signature STANDARD_SITE_SIG_BLOCK = STANDARD_SITE_SIG.appendArg("block", Block.class);
    public static final Signature STANDARD_SITE_SIG_1ARG_BLOCK = STANDARD_SITE_SIG_1ARG.appendArg("block", Block.class);
    public static final Signature STANDARD_SITE_SIG_2ARG_BLOCK = STANDARD_SITE_SIG_2ARG.appendArg("block", Block.class);
    public static final Signature STANDARD_SITE_SIG_3ARG_BLOCK = STANDARD_SITE_SIG_3ARG.appendArg("block", Block.class);
    public static final Signature STANDARD_SITE_SIG_NARG_BLOCK = STANDARD_SITE_SIG_NARG.appendArg("block", Block.class);
    public static final Signature[] STANDARD_SITE_SIGS_BLOCK = {
        STANDARD_SITE_SIG_BLOCK,
        STANDARD_SITE_SIG_1ARG_BLOCK,
        STANDARD_SITE_SIG_2ARG_BLOCK,
        STANDARD_SITE_SIG_3ARG_BLOCK,
        STANDARD_SITE_SIG_NARG_BLOCK,
    };

    public static final Signature STANDARD_SUPER_SIG = Signature
            .returning(IRubyObject.class)
            .appendArg("context", ThreadContext.class)
            .appendArg("caller", IRubyObject.class)
            .appendArg("self", IRubyObject.class)
            .appendArg("class", RubyClass.class);
}