Source/JavaScriptCore/bytecompiler/LabelScope.h

/*
 * Copyright (C) 2008 Apple Inc. 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 Apple Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include "Label.h"

namespace JSC {

class Identifier;

class LabelScope {
WTF_MAKE_NONCOPYABLE(LabelScope);
public:
    enum Type { Loop, Switch, NamedLabel };

    LabelScope(Type type, const Identifier* name, int scopeDepth, Ref<Label>&& breakTarget, RefPtr<Label>&& continueTarget)
        : m_refCount(0)
        , m_type(type)
        , m_name(name)
        , m_scopeDepth(scopeDepth)
        , m_breakTarget(WTFMove(breakTarget))
        , m_continueTarget(WTFMove(continueTarget))
    {
    }

    Label& breakTarget() const { return m_breakTarget.get(); }
    Label* continueTarget() const { return m_continueTarget.get(); }

    Type type() const { return m_type; }
    const Identifier* name() const { return m_name; }
    int scopeDepth() const { return m_scopeDepth; }

    void ref() { ++m_refCount; }
    void deref()
    {
        --m_refCount;
        ASSERT(m_refCount >= 0);
    }
    int refCount() const { return m_refCount; }
    bool hasOneRef() const { return m_refCount == 1; }

    bool breakTargetMayBeBound() const
    {
        if (!hasOneRef())
            return true;
        if (!m_breakTarget->hasOneRef())
            return true;
        return m_breakTarget->isBound();
    }

private:
    int m_refCount;
    Type m_type;
    const Identifier* m_name;
    int m_scopeDepth;
    Ref<Label> m_breakTarget;
    RefPtr<Label> m_continueTarget;
};

} // namespace JSC