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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <vespa/searchlib/parsequery/item_creator.h>
#include <cstddef>
#include <cstdint>
#ifndef JUNIPER_RPIF
#define JUNIPER_RPIF 1
#endif
/** @file query.h
* This file describes describes Juniper's expected interface for
* advanced query processing. Clients of Juniper wishing to receive optimal
* teasers based on the original query should use this interface.
* Design principle: visitor pattern - adapted to allow minimal overhead
* and opaque implementation (at binary level) of the IQueryItem class.
* Query provider (such as fsearch/qrserver/DS doc.proc.pipeline) should implement
* IQuery such that the appropriate Visit* functions of IQueryVisitor gets called
* Proper IQueryVisitor instance(s) is implemented by Juniper.
*
* Note that Juniper v.1.0.x also provides a more low level simple query
* interface through SimpleDynamicSummary. This interface only supports a query on
* the (abstract) form ((phrase|keyword) OR)* by means of a
* single string of null or space separated words and is depreciated as of Juniper v.2.0.x
*/
namespace juniper {
using ItemCreator = search::parseitem::ItemCreator;
// For debugging purposes: return a text string with the creator enum name
const char* creator_text(ItemCreator);
class IQueryVisitor;
// Interface class for juniper query items
class QueryItem;
/** This is the basic query type, implemented by the query provider
*/
class IQuery
{
public:
virtual ~IQuery() { }
/** Traverse the query.
* This will lead to a prefix depth first traversal of the complete query
* and calls to the appropriate Visitor functions.
*/
virtual bool Traverse(IQueryVisitor* v) const = 0;
/** Check if the index specification associated with the query item is useful from
* a Juniper perspective (see fsearchrc, highlightindexes parameter)
* @param item A query item to check
* @return true if this index is valid for Juniper, false otherwise
*/
virtual bool UsefulIndex(const QueryItem* item) const = 0;
};
/** IQueryVisitor is implemented by Juniper to enable Juniper to traverse the
* structure of an input query (Visitor pattern)
*/
class IQueryVisitor
{
public:
/** To be called upon by IQuery::Traverse visiting an AND query item
* @param item The (opaque to IQueryVisitor) item that is visited
* @param arity The number of children of this item
* @return if false, caller should skip calling this element's children visitors,
* otherwise caller should proceed as normal
*/
virtual bool VisitAND(const QueryItem* item, int arity) = 0;
/** To be called upon by IQuery::Traverse visiting an OR query item
* @param item The (opaque to IQueryVisitor) item that is visited
* @param arity The number of children of this item
* @return if false, caller should skip calling this element's children visitors,
* otherwise caller should proceed as normal
*/
virtual bool VisitOR(const QueryItem* item, int arity) = 0;
/** To be called upon by IQuery::Traverse visiting an AND query item
* @param item The (opaque to IQueryVisitor) item that is visited
* @param arity The number of children of this item
* @return if false, caller should skip calling this element's children visitors,
* otherwise caller should proceed as normal
*/
virtual bool VisitANY(const QueryItem* item, int arity) = 0;
/** To be called upon by IQuery::Traverse visiting a NEAR query item
* @param item The (opaque to IQueryVisitor) item that is visited
* @param arity The number of children of this item
* @param limit The number of words that defines the nearness wanted
* @return if false, caller should skip calling this element's children visitors,
* otherwise caller should proceed as normal
*/
virtual bool VisitNEAR(const QueryItem* item, int arity, int limit) = 0;
/** To be called upon by IQuery::Traverse visiting a WITHIN query item
* @param item The (opaque to IQueryVisitor) item that is visited
* @param arity The number of children of this item
* @param limit The number of words that defines the nearness wanted
* @return if false, caller should skip calling this element's children visitors,
* otherwise caller should proceed as normal
*/
virtual bool VisitWITHIN(const QueryItem* item, int arity, int limit) = 0;
/** To be called upon by IQuery::Traverse visiting a RANK query item
* @param item The (opaque to IQueryVisitor) item that is visited
* @param arity The number of children of this item
* @return if false, caller should skip calling this element's children visitors,
* otherwise caller should proceed as normal
*/
virtual bool VisitRANK(const QueryItem* item, int arity) = 0;
/** To be called upon by IQuery::Traverse visiting a PHRASE query item
* @param item The (opaque to IQueryVisitor) item that is visited
* @param arity The number of children of this item
* @return if false, caller should skip calling this element's children visitors,
* otherwise caller should proceed as normal
*/
virtual bool VisitPHRASE(const QueryItem* item, int arity) = 0;
/** To be called upon by IQuery::Traverse visiting an ANDNOT query item
* @param item The (opaque to IQueryVisitor) item that is visited
* @param arity The number of children of this item
* @return if false, caller should skip calling this element's children visitors,
* otherwise caller should proceed as normal
*/
virtual bool VisitANDNOT(const QueryItem* item, int arity) = 0;
/** To be called upon by IQuery::Traverse visiting any other query item
* than the ones handled by Juniper (to avoid inconsistency in the
* traversal wrt. arities)
* @param item The (opaque to IQueryVisitor) item that is visited
* @param arity The number of children of this item (may be 0 if leaf node)
* @return typically false to denote that caller should skip calling this
* element's children visitors,
*/
virtual bool VisitOther(const QueryItem* item, int arity) = 0;
/** Visit callback for the terminal type, to be called by IQuery::Traverse
* when encountering individual keywords
* @param item The (opaque to IQueryVisitor) item that is visited
* @param keyword Textual representation of the query keyword in question
* @param length Length of the keyword. If 0, it means keyword length is defined by
* null termination
* @param prefix true if prefix match with this term is desired
* otherwise caller should proceed as normal
* @param specialToken true if this term is treated as a special token
*/
virtual void VisitKeyword(const QueryItem* item,
const char* keyword, const size_t length = 0,
bool prefix = false, bool specialToken = false) = 0;
virtual ~IQueryVisitor() { }
};
}
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