ParallelScan.h

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/*
 * Souffle - A Datalog Compiler
 * Copyright (c) 2018, The Souffle Developers. All rights reserved
 * Licensed under the Universal Permissive License v 1.0 as shown at:
 * - https://opensource.org/licenses/UPL
 * - <souffle root>/licenses/SOUFFLE-UPL.txt
 */
 
/************************************************************************
 *
 * @file ParallelScan.h
 *
 * Defines the Operation of a relational algebra query.
 *
 ***********************************************************************/
 
#pragma once
 
#include "ram/AbstractParallel.h"
#include "ram/Operation.h"
#include "ram/Relation.h"
#include "ram/RelationOperation.h"
#include "ram/Scan.h"
#include "souffle/utility/MiscUtil.h"
#include "souffle/utility/StreamUtil.h"
#include <iosfwd>
#include <memory>
#include <ostream>
#include <string>
#include <utility>
 
namespace souffle::ram {
 
/**
 * @class ParallelScan
 * @brief Iterate all tuples of a relation in parallel
 *
 * An example:
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *  QUERY
 *   ...
 *   PARALLEL FOR t0 IN A
 *     ...
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
class ParallelScan : public Scan, public AbstractParallel {
public:
    ParallelScan(std::string rel, int ident, Own<Operation> nested, std::string profileText = "")
            : Scan(rel, ident, std::move(nested), profileText) {}
 
    ParallelScan* clone() const override {
        return new ParallelScan(relation, getTupleId(), souffle::clone(&getOperation()), getProfileText());
    }
 
protected:
    void print(std::ostream& os, int tabpos) const override {
        os << times(" ", tabpos);
        os << "PARALLEL FOR t" << getTupleId();
        os << " IN " << relation << std::endl;
        RelationOperation::print(os, tabpos + 1);
    }
};
}  // namespace souffle::ram