RewritingProcessor.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / Orcas / QFE / ndp / fx / src / DataEntity / System / Data / Map / ViewGeneration / QueryRewriting / RewritingProcessor.cs / 1 / RewritingProcessor.cs
                        

                        
                            using System; 
using System.Diagnostics;
using System.Collections.Generic;
using System.Text;
 
namespace System.Data.Mapping.ViewGeneration.QueryRewriting
{ 
    internal abstract class TileProcessor 
    {
        internal abstract bool IsEmpty(T_Tile tile); 
        internal abstract T_Tile Union(T_Tile a, T_Tile b);
        internal abstract T_Tile Join(T_Tile a, T_Tile b);
        internal abstract T_Tile AntiSemiJoin(T_Tile a, T_Tile b);
 
        internal abstract T_Tile GetArg1(T_Tile tile);
        internal abstract T_Tile GetArg2(T_Tile tile); 
        internal abstract TileOpKind GetOpKind(T_Tile tile); 
    }
 
    internal class RewritingProcessor : TileProcessor where T_Tile : class
    {
        public double PERMUTE_FRACTION = 0.0;
        public int MIN_PERMUTATIONS = 0; 
        public int MAX_PERMUTATIONS = 0;
        public bool REORDER_VIEWS = false; 
 
        private int m_numSATChecks;
        private int m_numIntersection; 
        private int m_numDifference;
        private int m_numUnion;

        private int m_numErrors; 

        private TileProcessor m_tileProcessor; 
 
        public RewritingProcessor(TileProcessor tileProcessor)
        { 
            m_tileProcessor = tileProcessor;
        }

        internal TileProcessor TileProcessor 
        {
            get { return m_tileProcessor; } 
        } 

        public void GetStatistics(out int numSATChecks, out int numIntersection, out int numUnion, out int numDifference, out int numErrors) 
        {
            numSATChecks = m_numSATChecks;
            numIntersection = m_numIntersection;
            numUnion = m_numUnion; 
            numDifference = m_numDifference;
            numErrors = m_numErrors; 
        } 

        public void PrintStatistics() 
        {
            Console.WriteLine("{0} containment checks, {4} set operations ({1} intersections + {2} unions + {3} differences)",
                m_numSATChecks, m_numIntersection, m_numUnion, m_numDifference,
                                m_numIntersection + m_numUnion + m_numDifference); 
            Console.WriteLine("{0} errors", m_numErrors);
        } 
 
        internal override T_Tile GetArg1(T_Tile tile)
        { 
            return m_tileProcessor.GetArg1(tile);
        }

        internal override T_Tile GetArg2(T_Tile tile) 
        {
            return m_tileProcessor.GetArg2(tile); 
        } 

        internal override TileOpKind GetOpKind(T_Tile tile) 
        {
            return m_tileProcessor.GetOpKind(tile);
        }
 
        internal override bool IsEmpty(T_Tile a)
        { 
            m_numSATChecks++; 
            return m_tileProcessor.IsEmpty(a);
        } 

        public bool IsDisjointFrom(T_Tile a, T_Tile b)
        {
            return m_tileProcessor.IsEmpty(Join(a, b)); 
        }
 
        internal bool IsContainedIn(T_Tile a, T_Tile b) 
        {
            T_Tile difference = AntiSemiJoin(a, b); 
            return IsEmpty(difference);
        }

        internal bool IsEquivalentTo(T_Tile a, T_Tile b) 
        {
            bool aInB = IsContainedIn(a, b); 
            bool bInA = IsContainedIn(b, a); 
            return aInB && bInA;
        } 

        internal override T_Tile Union(T_Tile a, T_Tile b)
        {
            m_numUnion++; 
            return m_tileProcessor.Union(a, b);
        } 
 
        internal override T_Tile Join(T_Tile a, T_Tile b)
        { 
            if (a == null)
            {
                return b;
            } 
            m_numIntersection++;
            return m_tileProcessor.Join(a, b); 
        } 

        internal override T_Tile AntiSemiJoin(T_Tile a, T_Tile b) 
        {
            m_numDifference++;
            return m_tileProcessor.AntiSemiJoin(a, b);
        } 

        public void AddError() 
        { 
            m_numErrors++;
        } 

        public int CountOperators(T_Tile query)
        {
            int count = 0; 
            if (query != null)
            { 
                if (GetOpKind(query) != TileOpKind.Named) 
                {
                    count++; 
                    count += CountOperators(GetArg1(query));
                    count += CountOperators(GetArg2(query));
                }
            } 
            return count;
        } 
 
        public int CountViews(T_Tile query)
        { 
            HashSet views = new HashSet();
            GatherViews(query, views);
            return views.Count;
        } 

        public void GatherViews(T_Tile rewriting, HashSet views) 
        { 
            if (rewriting != null)
            { 
                if (GetOpKind(rewriting) == TileOpKind.Named)
                {
                    views.Add(rewriting);
                } 
                else
                { 
                    GatherViews(GetArg1(rewriting), views); 
                    GatherViews(GetArg2(rewriting), views);
                } 
            }
        }

        public static IEnumerable AllButOne(IEnumerable list, int toSkipPosition) 
        {
            int valuePosition = 0; 
            foreach (T value in list) 
            {
                if (valuePosition++ != toSkipPosition) 
                {
                    yield return value;
                }
            } 
        }
 
        public static IEnumerable Concat(T value, IEnumerable rest) 
        {
            yield return value; 
            foreach (T restValue in rest)
            {
                yield return restValue;
            } 
        }
 
        public static IEnumerable> Permute(IEnumerable list) 
        {
            IEnumerable rest = null; 
            int valuePosition = 0;
            foreach (T value in list)
            {
                rest = AllButOne(list, valuePosition++); 
                foreach (IEnumerable restPermutation in Permute(rest))
                { 
                    yield return Concat(value, restPermutation); 
                }
            } 
            if (rest == null)
            {
                yield return list; // list is empty enumeration
            } 
        }
 
        static Random rnd = new Random(1507); 
        public static List RandomPermutation(IEnumerable input)
        { 
            List output = new List(input);
            for (int i = 0; i < output.Count; i++)
            {
                int j = rnd.Next(output.Count); 
                T tmp = output[i];
                output[i] = output[j]; 
                output[j] = tmp; 
            }
            return output; 
        }

        public static IEnumerable Reverse(IEnumerable input, HashSet filter)
        { 
            List output = new List(input);
            output.Reverse(); 
            foreach (T t in output) 
            {
                if (filter.Contains(t)) 
                {
                    yield return t;
                }
            } 
        }
 
        public bool RewriteQuery(T_Tile toFill, T_Tile toAvoid, IEnumerable views, out T_Tile rewriting) 
        {
            if (RewriteQueryOnce(toFill, toAvoid, views, out rewriting)) 
            {
                HashSet usedViews = new HashSet();
                GatherViews(rewriting, usedViews);
                int opCount = CountOperators(rewriting); 

                // try several permutations of views, pick one with fewer operators 
                T_Tile newRewriting; 
                int permuteTries = 0;
                int numPermutations = Math.Min(MAX_PERMUTATIONS, Math.Max(MIN_PERMUTATIONS, (int)(usedViews.Count * PERMUTE_FRACTION))); 
                while (permuteTries++ < numPermutations)
                {
                    IEnumerable permutedViews;
                    if (permuteTries == 1) 
                    {
                        permutedViews = Reverse(views, usedViews); 
                    } 
                    else
                    { 
                        permutedViews = RandomPermutation(usedViews); // Tradeoff: views vs. usedViews!
                    }
                    bool succeeded = RewriteQueryOnce(toFill, toAvoid, permutedViews, out newRewriting);
                    Debug.Assert(succeeded); 
                    int newOpCount = CountOperators(newRewriting);
                    if (newOpCount < opCount) 
                    { 
                        opCount = newOpCount;
                        rewriting = newRewriting; 
                    }
                    HashSet newUsedViews = new HashSet();
                    GatherViews(newRewriting, newUsedViews);
                    usedViews = newUsedViews; // can only be fewer! 
                }
                return true; 
            } 
            return false;
        } 

        public bool RewriteQueryOnce(T_Tile toFill, T_Tile toAvoid, IEnumerable views, out T_Tile rewriting)
        {
            List viewList = new List(views); 
            return RewritingPass.RewriteQuery(toFill, toAvoid, out rewriting, viewList, this);
        } 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
using System; 
using System.Diagnostics;
using System.Collections.Generic;
using System.Text;
 
namespace System.Data.Mapping.ViewGeneration.QueryRewriting
{ 
    internal abstract class TileProcessor 
    {
        internal abstract bool IsEmpty(T_Tile tile); 
        internal abstract T_Tile Union(T_Tile a, T_Tile b);
        internal abstract T_Tile Join(T_Tile a, T_Tile b);
        internal abstract T_Tile AntiSemiJoin(T_Tile a, T_Tile b);
 
        internal abstract T_Tile GetArg1(T_Tile tile);
        internal abstract T_Tile GetArg2(T_Tile tile); 
        internal abstract TileOpKind GetOpKind(T_Tile tile); 
    }
 
    internal class RewritingProcessor : TileProcessor where T_Tile : class
    {
        public double PERMUTE_FRACTION = 0.0;
        public int MIN_PERMUTATIONS = 0; 
        public int MAX_PERMUTATIONS = 0;
        public bool REORDER_VIEWS = false; 
 
        private int m_numSATChecks;
        private int m_numIntersection; 
        private int m_numDifference;
        private int m_numUnion;

        private int m_numErrors; 

        private TileProcessor m_tileProcessor; 
 
        public RewritingProcessor(TileProcessor tileProcessor)
        { 
            m_tileProcessor = tileProcessor;
        }

        internal TileProcessor TileProcessor 
        {
            get { return m_tileProcessor; } 
        } 

        public void GetStatistics(out int numSATChecks, out int numIntersection, out int numUnion, out int numDifference, out int numErrors) 
        {
            numSATChecks = m_numSATChecks;
            numIntersection = m_numIntersection;
            numUnion = m_numUnion; 
            numDifference = m_numDifference;
            numErrors = m_numErrors; 
        } 

        public void PrintStatistics() 
        {
            Console.WriteLine("{0} containment checks, {4} set operations ({1} intersections + {2} unions + {3} differences)",
                m_numSATChecks, m_numIntersection, m_numUnion, m_numDifference,
                                m_numIntersection + m_numUnion + m_numDifference); 
            Console.WriteLine("{0} errors", m_numErrors);
        } 
 
        internal override T_Tile GetArg1(T_Tile tile)
        { 
            return m_tileProcessor.GetArg1(tile);
        }

        internal override T_Tile GetArg2(T_Tile tile) 
        {
            return m_tileProcessor.GetArg2(tile); 
        } 

        internal override TileOpKind GetOpKind(T_Tile tile) 
        {
            return m_tileProcessor.GetOpKind(tile);
        }
 
        internal override bool IsEmpty(T_Tile a)
        { 
            m_numSATChecks++; 
            return m_tileProcessor.IsEmpty(a);
        } 

        public bool IsDisjointFrom(T_Tile a, T_Tile b)
        {
            return m_tileProcessor.IsEmpty(Join(a, b)); 
        }
 
        internal bool IsContainedIn(T_Tile a, T_Tile b) 
        {
            T_Tile difference = AntiSemiJoin(a, b); 
            return IsEmpty(difference);
        }

        internal bool IsEquivalentTo(T_Tile a, T_Tile b) 
        {
            bool aInB = IsContainedIn(a, b); 
            bool bInA = IsContainedIn(b, a); 
            return aInB && bInA;
        } 

        internal override T_Tile Union(T_Tile a, T_Tile b)
        {
            m_numUnion++; 
            return m_tileProcessor.Union(a, b);
        } 
 
        internal override T_Tile Join(T_Tile a, T_Tile b)
        { 
            if (a == null)
            {
                return b;
            } 
            m_numIntersection++;
            return m_tileProcessor.Join(a, b); 
        } 

        internal override T_Tile AntiSemiJoin(T_Tile a, T_Tile b) 
        {
            m_numDifference++;
            return m_tileProcessor.AntiSemiJoin(a, b);
        } 

        public void AddError() 
        { 
            m_numErrors++;
        } 

        public int CountOperators(T_Tile query)
        {
            int count = 0; 
            if (query != null)
            { 
                if (GetOpKind(query) != TileOpKind.Named) 
                {
                    count++; 
                    count += CountOperators(GetArg1(query));
                    count += CountOperators(GetArg2(query));
                }
            } 
            return count;
        } 
 
        public int CountViews(T_Tile query)
        { 
            HashSet views = new HashSet();
            GatherViews(query, views);
            return views.Count;
        } 

        public void GatherViews(T_Tile rewriting, HashSet views) 
        { 
            if (rewriting != null)
            { 
                if (GetOpKind(rewriting) == TileOpKind.Named)
                {
                    views.Add(rewriting);
                } 
                else
                { 
                    GatherViews(GetArg1(rewriting), views); 
                    GatherViews(GetArg2(rewriting), views);
                } 
            }
        }

        public static IEnumerable AllButOne(IEnumerable list, int toSkipPosition) 
        {
            int valuePosition = 0; 
            foreach (T value in list) 
            {
                if (valuePosition++ != toSkipPosition) 
                {
                    yield return value;
                }
            } 
        }
 
        public static IEnumerable Concat(T value, IEnumerable rest) 
        {
            yield return value; 
            foreach (T restValue in rest)
            {
                yield return restValue;
            } 
        }
 
        public static IEnumerable> Permute(IEnumerable list) 
        {
            IEnumerable rest = null; 
            int valuePosition = 0;
            foreach (T value in list)
            {
                rest = AllButOne(list, valuePosition++); 
                foreach (IEnumerable restPermutation in Permute(rest))
                { 
                    yield return Concat(value, restPermutation); 
                }
            } 
            if (rest == null)
            {
                yield return list; // list is empty enumeration
            } 
        }
 
        static Random rnd = new Random(1507); 
        public static List RandomPermutation(IEnumerable input)
        { 
            List output = new List(input);
            for (int i = 0; i < output.Count; i++)
            {
                int j = rnd.Next(output.Count); 
                T tmp = output[i];
                output[i] = output[j]; 
                output[j] = tmp; 
            }
            return output; 
        }

        public static IEnumerable Reverse(IEnumerable input, HashSet filter)
        { 
            List output = new List(input);
            output.Reverse(); 
            foreach (T t in output) 
            {
                if (filter.Contains(t)) 
                {
                    yield return t;
                }
            } 
        }
 
        public bool RewriteQuery(T_Tile toFill, T_Tile toAvoid, IEnumerable views, out T_Tile rewriting) 
        {
            if (RewriteQueryOnce(toFill, toAvoid, views, out rewriting)) 
            {
                HashSet usedViews = new HashSet();
                GatherViews(rewriting, usedViews);
                int opCount = CountOperators(rewriting); 

                // try several permutations of views, pick one with fewer operators 
                T_Tile newRewriting; 
                int permuteTries = 0;
                int numPermutations = Math.Min(MAX_PERMUTATIONS, Math.Max(MIN_PERMUTATIONS, (int)(usedViews.Count * PERMUTE_FRACTION))); 
                while (permuteTries++ < numPermutations)
                {
                    IEnumerable permutedViews;
                    if (permuteTries == 1) 
                    {
                        permutedViews = Reverse(views, usedViews); 
                    } 
                    else
                    { 
                        permutedViews = RandomPermutation(usedViews); // Tradeoff: views vs. usedViews!
                    }
                    bool succeeded = RewriteQueryOnce(toFill, toAvoid, permutedViews, out newRewriting);
                    Debug.Assert(succeeded); 
                    int newOpCount = CountOperators(newRewriting);
                    if (newOpCount < opCount) 
                    { 
                        opCount = newOpCount;
                        rewriting = newRewriting; 
                    }
                    HashSet newUsedViews = new HashSet();
                    GatherViews(newRewriting, newUsedViews);
                    usedViews = newUsedViews; // can only be fewer! 
                }
                return true; 
            } 
            return false;
        } 

        public bool RewriteQueryOnce(T_Tile toFill, T_Tile toAvoid, IEnumerable views, out T_Tile rewriting)
        {
            List viewList = new List(views); 
            return RewritingPass.RewriteQuery(toFill, toAvoid, out rewriting, viewList, this);
        } 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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