/*
 * Copyright (c) 2017, Oracle and/or its affiliates.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided
 * with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written
 * permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.oracle.truffle.llvm.parser.metadata;

import com.oracle.truffle.llvm.runtime.types.Type;
import com.oracle.truffle.llvm.runtime.types.VoidType;
import com.oracle.truffle.llvm.runtime.types.symbols.Symbol;

import java.util.function.Supplier;

public class MDSymbolReference extends MDTypedValue implements MDBaseNode {

    public static final MDSymbolReference VOID = new MDSymbolReference(VoidType.INSTANCE, null) {

        @Override
        public Symbol get() {
            throw new IndexOutOfBoundsException("VOID cannot be dereferenced!");
        }

        @Override
        public String toString() {
            return "VOID";
        }
    };

    private final Supplier<Symbol> valueSupplier;

    public MDSymbolReference(Type baseType, Supplier<Symbol> valueSupplier) {
        super(baseType);
        this.valueSupplier = valueSupplier;
    }

    public Symbol get() {
        return valueSupplier.get();
    }

    public boolean isPresent() {
        return valueSupplier.get() != null;
    }

    @Override
    public void accept(MetadataVisitor visitor) {
        visitor.visit(this);
    }

    @Override
    public String toString() {
        return String.format("SymbolRef (%s %s)", getType(), isPresent() ? get() : "<forward ref>");
    }
}