/*
 * Copyright (c) 2012, 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.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
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 */
package com.oracle.truffle.api.impl;

import com.oracle.truffle.api.Assumption;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.TruffleLanguage;
import com.oracle.truffle.api.nodes.Node;

public final class FindContextNode<C> extends Node {
    private final Class<? extends TruffleLanguage<C>> languageClass;
    @CompilerDirectives.CompilationFinal private C context;
    @CompilerDirectives.CompilationFinal private Assumption oneVM;

    public FindContextNode(Class<? extends TruffleLanguage<C>> type) {
        this.languageClass = type;
    }

    public C executeFindContext() {
        if (context != null && oneVM.isValid()) {
            return context;
        }
        CompilerDirectives.transferToInterpreterAndInvalidate();
        oneVM = Accessor.oneVMAssumption();
        return context = Accessor.findContext(languageClass);
    }

    public Class<? extends TruffleLanguage<C>> getLanguageClass() {
        return languageClass;
    }
}