GCC Code Coverage Report
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File: src/theory/output_channel.h Lines: 3 6 50.0 %
Date: 2021-03-22 Branches: 0 0 0.0 %

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/*********************                                                        */
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/*! \file output_channel.h
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 ** \verbatim
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 ** Top contributors (to current version):
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 **   Morgan Deters, Andrew Reynolds, Tim King
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 ** This file is part of the CVC4 project.
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 ** Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
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 ** in the top-level source directory and their institutional affiliations.
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 ** All rights reserved.  See the file COPYING in the top-level source
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 ** directory for licensing information.\endverbatim
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 **
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 ** \brief The theory output channel interface
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 **
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 ** The theory output channel interface.
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 **/
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#include "cvc4_private.h"
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#ifndef CVC4__THEORY__OUTPUT_CHANNEL_H
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#define CVC4__THEORY__OUTPUT_CHANNEL_H
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#include "theory/trust_node.h"
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#include "util/resource_manager.h"
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namespace CVC4 {
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namespace theory {
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/** Properties of lemmas */
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enum class LemmaProperty : uint32_t
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{
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  // default
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  NONE = 0,
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  // whether the lemma is removable
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  REMOVABLE = 1,
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  // whether the processing of the lemma should send atoms to the caller
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  SEND_ATOMS = 2,
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  // whether the lemma is part of the justification for answering "sat"
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  NEEDS_JUSTIFY = 4
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};
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/** Define operator lhs | rhs */
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LemmaProperty operator|(LemmaProperty lhs, LemmaProperty rhs);
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/** Define operator lhs |= rhs */
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LemmaProperty& operator|=(LemmaProperty& lhs, LemmaProperty rhs);
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/** Define operator lhs & rhs */
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LemmaProperty operator&(LemmaProperty lhs, LemmaProperty rhs);
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/** Define operator lhs &= rhs */
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LemmaProperty& operator&=(LemmaProperty& lhs, LemmaProperty rhs);
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/** is the removable bit set on p? */
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bool isLemmaPropertyRemovable(LemmaProperty p);
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/** is the send atoms bit set on p? */
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bool isLemmaPropertySendAtoms(LemmaProperty p);
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/** is the needs justify bit set on p? */
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bool isLemmaPropertyNeedsJustify(LemmaProperty p);
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/**
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 * Writes an lemma property name to a stream.
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 *
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 * @param out The stream to write to
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 * @param p The lemma property to write to the stream
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 * @return The stream
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 */
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std::ostream& operator<<(std::ostream& out, LemmaProperty p);
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class Theory;
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/**
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 * Generic "theory output channel" interface.
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 *
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 * All methods can throw unrecoverable CVC4::Exception's unless otherwise
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 * documented.
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 */
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class OutputChannel {
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 public:
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  /** Construct an OutputChannel. */
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  OutputChannel() {}
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  /**
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   * Destructs an OutputChannel.  This implementation does nothing,
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   * but we need a virtual destructor for safety in case subclasses
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   * have a destructor.
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   */
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  virtual ~OutputChannel() {}
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  OutputChannel(const OutputChannel&) = delete;
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  OutputChannel& operator=(const OutputChannel&) = delete;
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  /**
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   * With safePoint(), the theory signals that it is at a safe point
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   * and can be interrupted.
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   *
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   * @throws Interrupted if the theory can be safely interrupted.
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   */
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  virtual void safePoint(ResourceManager::Resource r) {}
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  /**
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   * Indicate a theory conflict has arisen.
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   *
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   * @param n - a conflict at the current decision level.  This should
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   * be an AND-kinded node of literals that are TRUE in the current
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   * assignment and are in conflict (i.e., at least one must be
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   * assigned false), or else a literal by itself (in the case of a
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   * unit conflict) which is assigned TRUE (and T-conflicting) in the
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   * current assignment.
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   */
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  virtual void conflict(TNode n) = 0;
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  /**
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   * Propagate a theory literal.
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   *
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   * @param n - a theory consequence at the current decision level
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   * @return false if an immediate conflict was encountered
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   */
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  virtual bool propagate(TNode n) = 0;
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  /**
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   * Tell the core that a valid theory lemma at decision level 0 has
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   * been detected.  (This requests a split.)
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   *
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   * @param n - a theory lemma valid at decision level 0
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   * @param p The properties of the lemma
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   */
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  virtual void lemma(TNode n, LemmaProperty p = LemmaProperty::NONE) = 0;
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  /**
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   * Request a split on a new theory atom.  This is equivalent to
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   * calling lemma({OR n (NOT n)}).
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   *
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   * @param n - a theory atom; must be of Boolean type
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   */
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  void split(TNode n);
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  virtual void splitLemma(TNode n, bool removable = false) = 0;
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  /**
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   * If a decision is made on n, it must be in the phase specified.
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   * Note that this is enforced *globally*, i.e., it is completely
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   * context-INdependent.  If you ever requirePhase() on a literal,
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   * it is phase-locked forever and ever.  If it is to ever have the
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   * other phase as its assignment, it will be because it has been
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   * propagated that way (or it's a unit, at decision level 0).
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   *
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   * @param n - a theory atom with a SAT literal assigned; must have
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   * been pre-registered
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   * @param phase - the phase to decide on n
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   */
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  virtual void requirePhase(TNode n, bool phase) = 0;
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  /**
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   * Notification from a theory that it realizes it is incomplete at
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   * this context level.  If SAT is later determined by the
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   * TheoryEngine, it should actually return an UNKNOWN result.
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   */
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  virtual void setIncomplete() = 0;
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  /**
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   * "Spend" a "resource."  The meaning is specific to the context in
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   * which the theory is operating, and may even be ignored.  The
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   * intended meaning is that if the user has set a limit on the "units
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   * of resource" that can be expended in a search, and that limit is
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   * exceeded, then the search is terminated.  Note that the check for
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   * termination occurs in the main search loop, so while theories
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   * should call OutputChannel::spendResource() during particularly
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   * long-running operations, they cannot rely on resource() to break
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   * out of infinite or intractable computations.
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   */
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  virtual void spendResource(ResourceManager::Resource r) {}
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  /**
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   * Handle user attribute.
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   * Associates theory t with the attribute attr.  Theory t will be
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   * notified whenever an attribute of name attr is set on a node.
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   * This can happen through, for example, the SMT-LIBv2 language.
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   */
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  virtual void handleUserAttribute(const char* attr, Theory* t) {}
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  /** Demands that the search restart from sat search level 0.
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   * Using this leads to non-termination issues.
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   * It is appropriate for prototyping for theories.
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   */
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  virtual void demandRestart() {}
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  //---------------------------- new proof
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  /**
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   * Let pconf be the pair (Node conf, ProofGenerator * pfg). This method
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   * sends conf on the output channel of this class whose proof can be generated
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   * by the generator pfg. Apart from pfg, the interface for this method is
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   * the same as OutputChannel.
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   */
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  virtual void trustedConflict(TrustNode pconf);
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  /**
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   * Let plem be the pair (Node lem, ProofGenerator * pfg).
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   * Send lem on the output channel of this class whose proof can be generated
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   * by the generator pfg. Apart from pfg, the interface for this method is
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   * the same as OutputChannel.
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   */
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  virtual void trustedLemma(TrustNode lem,
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                            LemmaProperty p = LemmaProperty::NONE);
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  //---------------------------- end new proof
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}; /* class OutputChannel */
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}  // namespace theory
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}  // namespace CVC4
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#endif /* CVC4__THEORY__OUTPUT_CHANNEL_H */