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//---------------------------------------------------------------------
// <copyright file="Tile.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
using System;
using System.Diagnostics;
using System.Collections.Generic;
using System.Text;
using System.Collections.ObjectModel;
using System.Linq;
using System.Globalization;
namespace System.Data.Mapping.ViewGeneration.QueryRewriting
{
internal enum TileOpKind
{
Union,
Join,
AntiSemiJoin,
// Project,
Named
}
internal interface ITileQuery
{
string Description { get; }
}
internal abstract class TileQueryProcessor<T_Query> where T_Query : ITileQuery
{
internal abstract T_Query Intersect(T_Query arg1, T_Query arg2);
internal abstract T_Query Difference(T_Query arg1, T_Query arg2);
internal abstract T_Query Union(T_Query arg1, T_Query arg2);
internal abstract bool IsSatisfiable(T_Query query);
internal abstract T_Query CreateDerivedViewBySelectingConstantAttributes(T_Query query);
}
internal class DefaultTileProcessor<T_Query> : TileProcessor<Tile<T_Query>> where T_Query : ITileQuery
{
private readonly TileQueryProcessor<T_Query> _tileQueryProcessor;
internal DefaultTileProcessor(TileQueryProcessor<T_Query> tileQueryProcessor)
{
_tileQueryProcessor = tileQueryProcessor;
}
internal TileQueryProcessor<T_Query> QueryProcessor
{
get { return _tileQueryProcessor; }
}
internal override bool IsEmpty(Tile<T_Query> tile)
{
return false == _tileQueryProcessor.IsSatisfiable(tile.Query);
}
internal override Tile<T_Query> Union(Tile<T_Query> arg1, Tile<T_Query> arg2)
{
return new TileBinaryOperator<T_Query>(arg1, arg2, TileOpKind.Union, _tileQueryProcessor.Union(arg1.Query, arg2.Query));
}
internal override Tile<T_Query> Join(Tile<T_Query> arg1, Tile<T_Query> arg2)
{
return new TileBinaryOperator<T_Query>(arg1, arg2, TileOpKind.Join, _tileQueryProcessor.Intersect(arg1.Query, arg2.Query));
}
internal override Tile<T_Query> AntiSemiJoin(Tile<T_Query> arg1, Tile<T_Query> arg2)
{
return new TileBinaryOperator<T_Query>(arg1, arg2, TileOpKind.AntiSemiJoin, _tileQueryProcessor.Difference(arg1.Query, arg2.Query));
}
internal override Tile<T_Query> GetArg1(Tile<T_Query> tile)
{
return tile.Arg1;
}
internal override Tile<T_Query> GetArg2(Tile<T_Query> tile)
{
return tile.Arg2;
}
internal override TileOpKind GetOpKind(Tile<T_Query> tile)
{
return tile.OpKind;
}
internal bool IsContainedIn(Tile<T_Query> arg1, Tile<T_Query> arg2)
{
return IsEmpty(AntiSemiJoin(arg1, arg2));
}
internal bool IsEquivalentTo(Tile<T_Query> arg1, Tile<T_Query> arg2)
{
return IsContainedIn(arg1, arg2) && IsContainedIn(arg2, arg1);
}
}
internal abstract class Tile<T_Query> where T_Query : ITileQuery
{
private readonly T_Query m_query;
private readonly TileOpKind m_opKind;
protected Tile(TileOpKind opKind, T_Query query)
{
m_opKind = opKind;
m_query = query;
}
public T_Query Query
{
get { return m_query; }
}
public abstract string Description { get; }
// multiple occurrences possible
public IEnumerable<T_Query> GetNamedQueries()
{
return GetNamedQueries(this);
}
private static IEnumerable<T_Query> GetNamedQueries(Tile<T_Query> rewriting)
{
if (rewriting != null)
{
if (rewriting.OpKind == TileOpKind.Named)
{
yield return ((TileNamed<T_Query>)rewriting).NamedQuery;
}
else
{
foreach (T_Query query in GetNamedQueries(rewriting.Arg1))
{
yield return query;
}
foreach (T_Query query in GetNamedQueries(rewriting.Arg2))
{
yield return query;
}
}
}
}
public override string ToString()
{
string formattedQuery = this.Description;
if (formattedQuery != null)
{
return String.Format(CultureInfo.InvariantCulture, "{0}: [{1}]", this.Description, this.Query);
}
else
{
return String.Format(CultureInfo.InvariantCulture, "[{0}]", this.Query);
}
}
public abstract Tile<T_Query> Arg1
{
get;
}
public abstract Tile<T_Query> Arg2
{
get;
}
public TileOpKind OpKind
{
get { return m_opKind; }
}
internal abstract Tile<T_Query> Replace(Tile<T_Query> oldTile, Tile<T_Query> newTile);
}
internal class TileNamed<T_Query> : Tile<T_Query> where T_Query : ITileQuery
{
public TileNamed(T_Query namedQuery)
: base(TileOpKind.Named, namedQuery)
{
Debug.Assert(namedQuery != null);
}
public T_Query NamedQuery
{
get { return this.Query; }
}
public override Tile<T_Query> Arg1 { get { return null; } }
public override Tile<T_Query> Arg2 { get { return null; } }
public override string Description
{
get { return this.Query.Description; }
}
public override string ToString()
{
return this.Query.ToString();
}
internal override Tile<T_Query> Replace(Tile<T_Query> oldTile, Tile<T_Query> newTile)
{
return (this == oldTile) ? newTile : this;
}
}
internal class TileBinaryOperator<T_Query> : Tile<T_Query> where T_Query : ITileQuery
{
private readonly Tile<T_Query> m_arg1;
private readonly Tile<T_Query> m_arg2;
public TileBinaryOperator(Tile<T_Query> arg1, Tile<T_Query> arg2, TileOpKind opKind, T_Query query)
: base(opKind, query)
{
Debug.Assert(arg1 != null && arg2 != null);
m_arg1 = arg1;
m_arg2 = arg2;
}
public override Tile<T_Query> Arg1 { get { return m_arg1; } }
public override Tile<T_Query> Arg2 { get { return m_arg2; } }
public override string Description
{
get
{
string descriptionFormat = null;
switch (OpKind)
{
case TileOpKind.Join: descriptionFormat = "({0} & {1})"; break;
case TileOpKind.AntiSemiJoin: descriptionFormat = "({0} - {1})"; break;
case TileOpKind.Union: descriptionFormat = "({0} | {1})"; break;
default: Debug.Fail("Unexpected binary operator"); break;
}
return String.Format(CultureInfo.InvariantCulture, descriptionFormat, this.Arg1.Description, this.Arg2.Description);
}
}
internal override Tile<T_Query> Replace(Tile<T_Query> oldTile, Tile<T_Query> newTile)
{
Tile<T_Query> newArg1 = Arg1.Replace(oldTile, newTile);
Tile<T_Query> newArg2 = Arg2.Replace(oldTile, newTile);
if (newArg1 != Arg1 || newArg2 != Arg2)
{
return new TileBinaryOperator<T_Query>(newArg1, newArg2, OpKind, Query);
}
return this;
}
}
}
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