using System; using System.Collections.Generic; using System.Linq; using System.Text; using Signum.Utilities.ExpressionTrees; using System.Linq.Expressions; using System.Diagnostics; using Signum.Engine.Maps; using Signum.Entities; using System.Reflection; using Signum.Utilities.Reflection; namespace Signum.Engine.Linq { public class QueryFilterer : SimpleExpressionVisitor { static GenericInvoker<Func<Schema, IQueryable, IQueryable>> miFilter = new GenericInvoker<Func<Schema, IQueryable, IQueryable>>((s,q) => s.OnFilterQuery<TypeDN>((IQueryable<TypeDN>)q)); protected override Expression VisitConstant(ConstantExpression c) { if (typeof(IQueryable).IsAssignableFrom(c.Type)) { IQueryable query = (IQueryable)c.Value; if (query.IsBase() && typeof(IdentifiableEntity).IsAssignableFrom(query.ElementType)) { IQueryable newQuery = miFilter.GetInvoker(c.Type.GetGenericArguments())(Schema.Current, query); if (newQuery != query) return newQuery.Expression; return c; } else { /// <summary> /// Replaces every expression like ConstantExpression{ Type = IQueryable, Value = complexExpr } by complexExpr /// </summary> return DbQueryProvider.Clean(query.Expression); } } return base.VisitConstant(c); } internal static Expression Filter(Expression expression) { return new QueryFilterer().Visit(expression); } } }
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