136 lines
3.5 KiB
C++
136 lines
3.5 KiB
C++
/*
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----
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This file is part of SECONDO.
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Copyright (C) 2004, University in Hagen, Department of Computer Science,
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Database Systems for New Applications.
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SECONDO is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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SECONDO is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with SECONDO; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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----
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*/
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#include "Attr.h"
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#include "AttrArray.h"
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#include <cstdint>
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#include <exception>
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#include "LogMsg.h"
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#include "OperatorUtils.h"
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#include "QueryProcessor.h"
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#include "StandardTypes.h"
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#include <string>
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#include "Symbols.h"
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#include "../TBlock.h"
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#include "../TypeConstructors/TBlockTC.h"
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using namespace CRelAlgebra;
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using namespace CRelAlgebra::Operators;
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using std::exception;
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using std::string;
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extern NestedList *nl;
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extern QueryProcessor *qp;
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Attr::Attr() :
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Operator(info, ValueMapping, TypeMapping)
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{
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SetUsesArgsInTypeMapping();
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}
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const OperatorInfo Attr::info = OperatorInfo(
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"attr", "tblock x symbol -> ATTRARRAY",
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"attr(_, _)",
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"Returns the column of the tuple block which has the given name.",
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"query people feed filter[attr(., Age) > 50] count");
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ListExpr Attr::TypeMapping(ListExpr args)
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{
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//Expect two arguments
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if (!nl->HasLength(args, 2))
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{
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return GetTypeError("Expected two arguments!");
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}
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//Check the first argument for 'tblock' type
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ListExpr tblockType = nl->First(nl->First(args));
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if (!TBlockTI::Check(tblockType))
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{
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return GetTypeError(0 , "block", "Not of type tblock.");
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}
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//Check the second argument for 'symbol' type
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ListExpr columnNameExpr = nl->Second(nl->Second(args));
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if (!nl->IsNodeType(SymbolType, columnNameExpr))
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{
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return GetTypeError(1, "column name", "Not of type symbol.");
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}
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//Find the column with matching name
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const string columnName = nl->SymbolValue(columnNameExpr);
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const TBlockTI tblockInfo(tblockType, false);
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uint64_t index = 0;
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for (const TBlockTI::ColumnInfo &columnInfo : tblockInfo.columnInfos)
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{
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if (columnInfo.name == columnName)
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{
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//Append the matching column's index
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//Result type is the matching column's type
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return nl->ThreeElemList(nl->SymbolAtom(Symbols::APPEND()),
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nl->OneElemList(nl->IntAtom(index)),
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columnInfo.type);
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}
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++index;
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}
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return GetTypeError(1, "column name", "No such column.");
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}
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int Attr::ValueMapping(ArgVector args, Word &result, int, Word&, Supplier s)
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{
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try
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{
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const TBlock &block = *(TBlock*)args[0].addr;
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const CcInt &attributeIndex = *(CcInt*)args[2].addr;
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//Don't want to return a new instance so delete it
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qp->DeleteResultStorage(s);
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AttrArray *array = &block[attributeIndex.GetValue()];
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array->IncRef();
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//Return the pointer to the column
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//Let the delete function only decrease the ref-count
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qp->ChangeResultStorage(s, result = Word(array));
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qp->SetDeleteFunction(s, [](const ListExpr, Word &value)
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{
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((AttrArray*)value.addr)->DecRef();
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});
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return 0;
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}
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catch (const exception &e)
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{
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ErrorReporter::ReportError(e.what());
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}
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return FAILURE;
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}
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