/*
 * Copyright (c) 2014, 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.
 *
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package jdk.nashorn.internal.codegen;

import java.util.ArrayList;
import java.util.List;
import jdk.nashorn.internal.ir.CompileUnitHolder;
import jdk.nashorn.internal.ir.FunctionNode;
import jdk.nashorn.internal.ir.FunctionNode.CompilationState;
import jdk.nashorn.internal.ir.LexicalContext;
import jdk.nashorn.internal.ir.LiteralNode;
import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode;
import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode.ArrayUnit;
import jdk.nashorn.internal.ir.Node;
import jdk.nashorn.internal.ir.visitor.NodeVisitor;

/**
 * Base class for a node visitor that replaces {@link CompileUnit}s in {@link CompileUnitHolder}s.
 */
abstract class ReplaceCompileUnits extends NodeVisitor<LexicalContext> {
    ReplaceCompileUnits() {
        super(new LexicalContext());
    }

    /**
     * Override to provide a replacement for an old compile unit.
     * @param oldUnit the old compile unit to replace
     * @return the compile unit's replacement.
     */
    abstract CompileUnit getReplacement(final CompileUnit oldUnit);

    CompileUnit getExistingReplacement(final CompileUnitHolder node) {
        final CompileUnit oldUnit = node.getCompileUnit();
        assert oldUnit != null;

        final CompileUnit newUnit = getReplacement(oldUnit);
        assert newUnit != null;

        return newUnit;
    }

    @Override
    public Node leaveFunctionNode(final FunctionNode node) {
        return node.setCompileUnit(lc, getExistingReplacement(node)).setState(lc, CompilationState.COMPILE_UNITS_REUSED);
    }

    @Override
    public Node leaveLiteralNode(final LiteralNode<?> node) {
        if (node instanceof ArrayLiteralNode) {
            final ArrayLiteralNode aln = (ArrayLiteralNode)node;
            if (aln.getUnits() == null) {
                return node;
            }
            final List<ArrayUnit> newArrayUnits = new ArrayList<>();
            for (final ArrayUnit au : aln.getUnits()) {
                newArrayUnits.add(new ArrayUnit(getExistingReplacement(au), au.getLo(), au.getHi()));
            }
            return aln.setUnits(lc, newArrayUnits);
        }
        return node;
    }
}