218 lines
9.2 KiB
C#
218 lines
9.2 KiB
C#
using PoweredSoft.DynamicLinq.Dal.Pocos;
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using PoweredSoft.DynamicLinq.Helpers;
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using PoweredSoft.DynamicLinq.Parser;
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Linq.Expressions;
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namespace PoweredSoft.DynamicLinq.ConsoleApp
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{
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public class BetterProto2
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{
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/*
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* (parent, innerExpression, innerExpressionLambda) =>
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{
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var listGenericArgumentType = parent.Type.GetGenericArguments().First();
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Expression ret = null;
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if (selectCollectionHandling == SelectCollectionHandling.LeaveAsIs || !QueryableHelpers.IsGenericEnumerable(innerExpression))
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ret = Expression.Call(typeof(Enumerable), "Select", new Type[] { listGenericArgumentType, innerExpression.Type }, parent, innerExpressionLambda);
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else
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ret = Expression.Call(typeof(Enumerable), "SelectMany", new Type[] { listGenericArgumentType, innerExpression.Type.GenericTypeArguments.First() }, parent, innerExpressionLambda);
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return ret;
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}
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*/
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public static void Run()
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{
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//Case1();
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Case2();
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}
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public static void Case1()
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{
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// the expression parser.
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var ep = new ExpressionParser(typeof(Author), "Posts.Comments.Id");
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// the builder.
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var per = new PathExpressionResolver(ep);
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per.Resolve();
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// the result expression.
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var result = per.Result;
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}
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public static void Case2()
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{
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// the expression parser.
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var ep = new ExpressionParser(typeof(Author), "Posts.Author.Website.Url");
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new List<Author>().AsQueryable().Select(t => new
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{
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A = t.Posts.Select(t2 => t2.Author.Posts.Select(t3 => t3.Author.Website.Url)) ,
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B = t.Posts.Where(t2 => t2.Author != null).Select(t2 => t2.Author.Posts.Where(t3 => t3.Author != null && t3.Author.Website != null).Select(t3 => t3.Author.Website.Url))
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});
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new List<Post>().AsQueryable().Select(t => new
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{
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FirstNames = t.Author == null ? new List<string>() : (t.Author.Posts == null ? new List<string>() : t.Author.Posts.Where(t2 => t2.Author != null).Select(t2 => t2.Author.FirstName)),
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PostsAuthors = t.Author == null ? new List<Author>() : (t.Author.Posts == null ? new List<Author>() : t.Author.Posts.Where(t2 => t2.Author != null).Select(t2 => t2.Author)),
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Comments = t.Comments == null ? new List<Comment>() : t.Comments,
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CommentLikes = (t.Comments == null ? new List<CommentLike>() : t.Comments.Where(t2 => t2.CommentLikes != null).SelectMany(t2 => t2.CommentLikes)),
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CommentLikeIds = (t.Comments == null ? new List<long>() : t.Comments.Where(t2 => t2.CommentLikes != null).SelectMany(t2 => t2.CommentLikes.Select(t3 => t3.Id))),
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CommentsLikes = (t.Comments == null ? new List<List<CommentLike>>() : t.Comments.Where(t2 => t2.CommentLikes != null).Select(t2 => t2.CommentLikes))
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});
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// the builder.
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var per = new PathExpressionResolver(ep);
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per.NullHandling = SelectNullHandling.Handle;
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per.Resolve();
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// the result expression.
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var result = per.Result;
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}
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}
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public class PathExpressionResolver
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{
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public SelectNullHandling NullHandling { get; set; } = SelectNullHandling.LeaveAsIs;
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public SelectCollectionHandling CollectionHandling { get; set; } = SelectCollectionHandling.LeaveAsIs;
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public ExpressionParser Parser { get; protected set; }
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public Expression Result { get; protected set; }
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public Type NullType { get; set; }
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public PathExpressionResolver(ExpressionParser parser)
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{
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Parser = parser;
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}
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protected Expression CompileGroup(ExpressionParserPieceGroup group, SelectNullHandling NullHandling)
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{
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var expr = group.Parameter as Expression;
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group.Pieces.ForEach(piece =>
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{
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expr = Expression.PropertyOrField(expr, piece.Name);
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});
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return expr;
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}
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public void Resolve()
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{
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Result = null;
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// parse the expression.
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Parser.Parse();
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// group the piece by common parameters
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var groups = Parser.GroupBySharedParameters();
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NullType = groups.ResolveNullHandlingType();
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Expression currentExpression = null;
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foreach(var group in groups.Reversed())
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{
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if (currentExpression == null)
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{
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var groupExpression = CompileGroup(group, NullHandling);
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var groupExpressionLambda = Expression.Lambda(groupExpression, group.Parameter);
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if (group.Parent == null)
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{
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currentExpression = groupExpressionLambda;
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continue;
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}
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var parent = group.Parent;
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var parentExpression = CompileGroup(parent, NullHandling);
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// check null with where.
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if (NullHandling != SelectNullHandling.LeaveAsIs)
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parentExpression = CheckNullOnEnumerableParent(group, parent, parentExpression);
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// the select expression.
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var selectType = parent.GroupEnumerableType();
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var selectExpression = Expression.Call(typeof(Enumerable), "Select",
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new Type[] { selectType, groupExpression.Type },
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parentExpression, groupExpressionLambda);
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currentExpression = selectExpression;
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}
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else
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{
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if (group.Parent == null)
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{
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if (NullHandling != SelectNullHandling.LeaveAsIs)
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currentExpression = CheckNullOnFirstGroup(group, currentExpression);
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currentExpression = Expression.Lambda(currentExpression, group.Parameter);
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continue;
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}
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var parent = group.Parent;
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var parentExpression = CompileGroup(parent, NullHandling);
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var selectType = parent.GroupEnumerableType();
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if (NullHandling != SelectNullHandling.LeaveAsIs)
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parentExpression = CheckNullOnEnumerableParent(group, parent, parentExpression);
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var currentExpressionLambda = Expression.Lambda(currentExpression, group.Parameter);
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currentExpression = Expression.Call(typeof(Enumerable), "Select",
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new Type[] { selectType, currentExpression.Type },
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parentExpression, currentExpressionLambda);
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}
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}
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Result = currentExpression;
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}
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private Expression CheckNullOnFirstGroup(ExpressionParserPieceGroup group, Expression currentExpression)
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{
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var path = string.Join(".", group.Pieces.Select(t => t.Name));
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var whereExpression = QueryableHelpers.CreateConditionExpression(group.Parameter.Type, path,
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ConditionOperators.NotEqual, null, QueryConvertStrategy.ConvertConstantToComparedPropertyOrField,
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parameter: group.Parameter, nullChecking: true);
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var whereBodyExpression = (whereExpression as LambdaExpression).Body;
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Expression ifTrueExpression = null;
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if (QueryableHelpers.IsGenericEnumerable(NullType))
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{
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var listType = typeof(List<>).MakeGenericType(NullType.GenericTypeArguments.First());
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ifTrueExpression = Expression.New(listType);
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}
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else
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{
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ifTrueExpression = Expression.Default(NullType);
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}
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return Expression.Condition(whereBodyExpression, ifTrueExpression, currentExpression, currentExpression.Type);
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}
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private static Expression CheckNullOnEnumerableParent(ExpressionParserPieceGroup group, ExpressionParserPieceGroup parent, Expression parentExpression)
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{
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if (group.Pieces.Count > 1)
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{
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var path = string.Join(".", group.Pieces.Take(group.Pieces.Count - 1).Select(T => T.Name));
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var whereExpression = QueryableHelpers.CreateConditionExpression(group.Parameter.Type, path,
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ConditionOperators.NotEqual, null, QueryConvertStrategy.ConvertConstantToComparedPropertyOrField,
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parameter: group.Parameter, nullChecking: true);
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//public static IEnumerable<TSource> Where<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate);
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parentExpression = Expression.Call(typeof(Enumerable), "Where",
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new Type[] { parent.GroupEnumerableType() },
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parentExpression, whereExpression);
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}
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else
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{
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}
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return parentExpression;
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}
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}
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}
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