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