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/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
#pragma once
#include "atn/PredictionContext.h"
namespace antlr4 {
namespace atn {
class ANTLR4CPP_PUBLIC SingletonPredictionContext final : public PredictionContext {
public:
static bool is(const PredictionContext &predictionContext) { return predictionContext.getContextType() == PredictionContextType::SINGLETON; }
static bool is(const PredictionContext *predictionContext) { return predictionContext != nullptr && is(*predictionContext); }
static Ref<const SingletonPredictionContext> create(Ref<const PredictionContext> parent, size_t returnState);
// Usually a parent is linked via a weak ptr. Not so here as we have kinda reverse reference chain.
// There are no child contexts stored here and often the parent context is left dangling when it's
// owning ATNState is released. In order to avoid having this context released as well (leaving all other contexts
// which got this one as parent with a null reference) we use a shared_ptr here instead, to keep those left alone
// parent contexts alive.
const Ref<const PredictionContext> parent;
const size_t returnState;
SingletonPredictionContext(Ref<const PredictionContext> parent, size_t returnState);
bool isEmpty() const override;
size_t size() const override;
const Ref<const PredictionContext>& getParent(size_t index) const override;
size_t getReturnState(size_t index) const override;
bool equals(const PredictionContext &other) const override;
std::string toString() const override;
protected:
size_t hashCodeImpl() const override;
};
} // namespace atn
} // namespace antlr4
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