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well advanced null checking on select expression big deal! :D

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This commit is contained in:
David Lebée 2018-04-04 21:57:40 -05:00
parent 1be2458591
commit 13576133b5
2 changed files with 112 additions and 25 deletions
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131
PoweredSoft.DynamicLinq.ConsoleApp/BetterProto2.cs
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@ -4,8 +4,6 @@ using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading.Tasks;
namespace PoweredSoft.DynamicLinq.ConsoleApp
{
@ -60,6 +58,7 @@ namespace PoweredSoft.DynamicLinq.ConsoleApp
// the builder.
var per = new PathExpressionResolver(ep);
per.NullChecking = SelectNullHandling.New;
per.Resolve();
// the result expression.
@ -73,6 +72,7 @@ namespace PoweredSoft.DynamicLinq.ConsoleApp
public bool IsGenericEnumerable { get; set; }
public Type EnumerableType { get; set; }
public ExpressionParserPiece Parent { get; set; }
public string Name { get; internal set; }
}
public class PathExpressionResolver
@ -82,8 +82,6 @@ namespace PoweredSoft.DynamicLinq.ConsoleApp
public ExpressionParser Parser { get; protected set; }
public Expression Result { get; protected set; }
protected Expression NullCheckValueExpression { get; set; }
public PathExpressionResolver(ExpressionParser parser)
{
Parser = parser;
@ -96,20 +94,58 @@ namespace PoweredSoft.DynamicLinq.ConsoleApp
// parse the expression.
Parser.Parse();
// resolve the expression to use during a conditional if null checking is enabled.
ResolveNullCheckingRightType();
// reverse foreach
Parser.Pieces.ReversedForEach((piece, index) =>
{
if (piece.Parent == null)
return;
var last = Parser.Pieces.Last();
if (piece.Parent.IsGenericEnumerable)
HandleCollection(piece, index);
});
// reverse recursive.
Result = RecursiveSelect(last);
}
protected Expression RecursiveSelect(ExpressionParserPiece piece)
{
if (piece.Parent == null)
{
var parameter = Parser.Parameter;
var me = Expression.PropertyOrField(Parser.Parameter, piece.Name);
return me;
}
else if (piece.Parent.IsGenericEnumerable)
{
var indexOfPiece = Parser.Pieces.IndexOf(piece);
var currentSimpleChain = Parser.Pieces.Skip(indexOfPiece - 1).Where(t => !t.IsGenericEnumerable).ToList();
var parameter = ResolveParameter(currentSimpleChain);
var currentSimpleChainExpression = BuildSimpleChainExpression(currentSimpleChain, parameter);
var currentSimpleChainExpressionLambda = Expression.Lambda(currentSimpleChainExpression, parameter);
// the left before the parent.
var left = RecursiveSelect(piece.Parent);
// the parent.
var parent = Expression.PropertyOrField(left, piece.Parent.Name) as Expression;
if (NullChecking != SelectNullHandling.LeaveAsIs)
{
var nullCheckParameter = ResolveParameter(currentSimpleChain);
var nullCheckConditionExpression = BuildNullCheckConditionExpression(currentSimpleChain, nullCheckParameter);
var whereExpression = Expression.Call(typeof(Enumerable), "Where", new[] { piece.Parent.EnumerableType }, parent, nullCheckConditionExpression);
parent = whereExpression as Expression;
}
// select.
var allPiecesAttached = Expression.Call(typeof(Enumerable),
"Select",
new Type[] { piece.Parent.EnumerableType, currentSimpleChainExpression.Type },
parent, currentSimpleChainExpressionLambda);
// add current to parent?
return allPiecesAttached;
}
// skip.
return RecursiveSelect(piece.Parent);
}
/*
private void ResolveNullCheckingRightType()
{
if (NullChecking == SelectNullHandling.LeaveAsIs)
@ -117,27 +153,75 @@ namespace PoweredSoft.DynamicLinq.ConsoleApp
// last piece.
var lastPiece = Parser.Pieces.Last();
var anyCollections = Parser.Pieces.Any(t => t.IsGenericEnumerable);
// the subject type
Type subjectType = null;
if (lastPiece.IsGenericEnumerable)
if (anyCollections)
subjectType = typeof(List<>).MakeGenericType(lastPiece.EnumerableType);
else
subjectType = lastPiece.Type;
if (NullChecking == SelectNullHandling.Default)
NullCheckValueExpression = Expression.Default(subjectType);
else
NullCheckValueExpression = Expression.New(subjectType);
}
}*/
private void HandleCollection(ExpressionParserPiece piece, int index)
{
// simple parent.
/*
if (Result == null)
HandleNoPreviousResultCollection(piece, index);
// the current simple chain.
var currentSimpleChain = Parser.Pieces.Skip(index - 1).Where(t => !t.IsGenericEnumerable).ToList();
// the parameter being used to select.
var parameter = ResolveParameter(currentSimpleChain);
// this is the simple chain to select.
var currentSimpleChainExpression = BuildSimpleChainExpression(currentSimpleChain, parameter);
// add where :)
if (NullChecking != SelectNullHandling.LeaveAsIs)
{
var nullCheckParameter = ResolveParameter(currentSimpleChain);
var nullCheckWhereForChain = BuildNullCheckConditionExpression(currentSimpleChain, nullCheckParameter);
}
else
HandlePreviousResultCollection(piece, index);*/
{
Result = currentSimpleChainExpression;
}
}
private Expression BuildNullCheckConditionExpression(List<ExpressionParserPiece> currentSimpleChain, ParameterExpression parameter)
{
var path = string.Join(".", currentSimpleChain.Select(t => t.Name).Take(currentSimpleChain.Count - 1));
var where = QueryableHelpers.CreateConditionExpression(parameter.Type, path, ConditionOperators.NotEqual, null, QueryConvertStrategy.ConvertConstantToComparedPropertyOrField,
nullChecking: true, parameter: parameter);
return where;
}
private ParameterExpression ResolveParameter(List<ExpressionParserPiece> currentSimpleChain)
{
var first = currentSimpleChain.First();
if (first.Parent == null)
return Parser.Parameter;
if (first.Parent.IsGenericEnumerable)
return Expression.Parameter(first.Parent.EnumerableType);
throw new NotSupportedException();
}
private Expression BuildSimpleChainExpression(List<ExpressionParserPiece> currentSimpleChain, ParameterExpression parameter)
{
var ret = parameter as Expression;
currentSimpleChain.ForEach(p =>
{
var me = Expression.PropertyOrField(ret, p.Name);
ret = me;
});
return ret;
}
/*
@ -215,7 +299,8 @@ namespace PoweredSoft.DynamicLinq.ConsoleApp
Type = memberExpression.Type,
IsGenericEnumerable = QueryableHelpers.IsGenericEnumerable(memberExpression),
EnumerableType = memberExpression.Type.GenericTypeArguments.FirstOrDefault(),
Parent = parent
Parent = parent,
Name = pp
};
Pieces.Add(current);

6
PoweredSoft.DynamicLinq/Helpers/QueryableHelpers.cs
View File

@ -434,8 +434,10 @@ namespace PoweredSoft.DynamicLinq.Helpers
if (nullCheckExpression != null)
{
var pathExpr = InternalCreateConditionExpression(recursionStep, type, parameter, memberExpression, parts.Skip(1).ToList(), condition, value, convertStrategy, collectionHandling, nullChecking, stringComparison);
var nullCheckResult = Expression.AndAlso(nullCheckExpression, pathExpr);
return nullCheckResult;
var nullCheckResult = Expression.AndAlso(nullCheckExpression, (pathExpr as LambdaExpression).Body);
var nullCheckResultLambda = Expression.Lambda((Expression)nullCheckResult, parameter);
return nullCheckResultLambda;
}
return InternalCreateConditionExpression(recursionStep, type, parameter, memberExpression, parts.Skip(1).ToList(), condition, value, convertStrategy, collectionHandling, nullChecking, stringComparison);