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750 lines
31 KiB
C#
750 lines
31 KiB
C#
//---------------------------------------------------------------------
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// <copyright file="Funcletizer.cs" company="Microsoft">
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// Copyright (c) Microsoft Corporation. All rights reserved.
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// </copyright>
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//
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// @owner Microsoft
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// @backupOwner Microsoft
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//---------------------------------------------------------------------
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namespace System.Data.Objects.ELinq
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{
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using System.Collections.Generic;
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using System.Collections.ObjectModel;
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using System.Data.Common.CommandTrees;
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using System.Data.Common.CommandTrees.ExpressionBuilder;
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using System.Data.Entity;
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using System.Data.Metadata.Edm;
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using System.Diagnostics;
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using System.Globalization;
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using System.Linq;
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using System.Linq.Expressions;
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using System.Reflection;
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/// <summary>
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/// Determines which leaves of a LINQ expression tree should be evaluated locally before
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/// sending a query to the store. These sub-expressions may map to query parameters (e.g. local variables),
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/// to constants (e.g. literals 'new DateTime(2008, 1, 1)') or query sub-expression
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/// (e.g. 'context.Products'). Parameter expressions are replaced with QueryParameterExpression
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/// nodes. All other elements are swapped in place with either expanded expressions (for sub-queries)
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/// or constants. Where the expression includes mutable state that may influence the translation
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/// to a query, a Func(Of Boolean) delegate is returned indicating when a recompilation is necessary.
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/// </summary>
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internal sealed class Funcletizer
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{
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// Compiled query information
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private readonly ParameterExpression _rootContextParameter;
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private readonly ObjectContext _rootContext;
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private readonly ConstantExpression _rootContextExpression;
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private readonly ReadOnlyCollection<ParameterExpression> _compiledQueryParameters;
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private readonly Mode _mode;
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private readonly HashSet<Expression> _linqExpressionStack = new HashSet<Expression>();
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// Object parameters
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private static readonly string s_parameterPrefix = "p__linq__";
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private long _parameterNumber;
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private Funcletizer(
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Mode mode,
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ObjectContext rootContext,
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ParameterExpression rootContextParameter,
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ReadOnlyCollection<ParameterExpression> compiledQueryParameters)
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{
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_mode = mode;
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_rootContext = rootContext;
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_rootContextParameter = rootContextParameter;
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_compiledQueryParameters = compiledQueryParameters;
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if (null != _rootContextParameter && null != _rootContext)
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{
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_rootContextExpression = Expression.Constant(_rootContext);
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}
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}
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internal static Funcletizer CreateCompiledQueryEvaluationFuncletizer(
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ObjectContext rootContext,
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ParameterExpression rootContextParameter,
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ReadOnlyCollection<ParameterExpression> compiledQueryParameters)
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{
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EntityUtil.CheckArgumentNull(rootContext, "rootContext");
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EntityUtil.CheckArgumentNull(rootContextParameter, "rootContextParameter");
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EntityUtil.CheckArgumentNull(compiledQueryParameters, "compiledQueryParameters");
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return new Funcletizer(Mode.CompiledQueryEvaluation, rootContext, rootContextParameter, compiledQueryParameters);
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}
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internal static Funcletizer CreateCompiledQueryLockdownFuncletizer()
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{
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return new Funcletizer(Mode.CompiledQueryLockdown, null, null, null);
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}
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internal static Funcletizer CreateQueryFuncletizer(ObjectContext rootContext)
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{
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EntityUtil.CheckArgumentNull(rootContext, "rootContext");
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return new Funcletizer(Mode.ConventionalQuery, rootContext, null, null);
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}
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internal ObjectContext RootContext
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{
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get { return _rootContext; }
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}
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internal ParameterExpression RootContextParameter
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{
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get { return _rootContextParameter; }
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}
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internal ConstantExpression RootContextExpression
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{
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get { return _rootContextExpression; }
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}
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internal bool IsCompiledQuery
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{
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get { return _mode == Mode.CompiledQueryEvaluation || _mode == Mode.CompiledQueryLockdown; }
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}
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/// <summary>
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/// Performs funcletization on the given expression. Also returns a delegates that can be used
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/// to determine if the entire tree needs to be recompiled.
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/// </summary>
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internal Expression Funcletize(Expression expression, out Func<bool> recompileRequired)
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{
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EntityUtil.CheckArgumentNull(expression, "expression");
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// Find all candidates for funcletization. Some sub-expressions are reduced to constants,
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// others are reduced to variables. The rules vary based on the _mode.
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Func<Expression, bool> isClientConstant;
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Func<Expression, bool> isClientVariable;
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expression = ReplaceRootContextParameter(expression);
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if (_mode == Mode.CompiledQueryEvaluation)
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{
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// We lock down closure expressions for compiled queries, so everything is either
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// a constant or a query parameter produced from the explicit parameters to the
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// compiled query delegate.
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isClientConstant = Nominate(expression, this.IsClosureExpression);
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isClientVariable = Nominate(expression, this.IsCompiledQueryParameterVariable);
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}
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else if (_mode == Mode.CompiledQueryLockdown)
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{
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// When locking down a compiled query, we can evaluate all closure expressions.
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isClientConstant = Nominate(expression, this.IsClosureExpression);
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isClientVariable = (exp) => false;
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}
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else
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{
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Debug.Assert(_mode == Mode.ConventionalQuery, "No other options...");
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// There are no variable parameters outside of compiled queries, so everything is
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// either a constant or a closure expression.
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isClientConstant = Nominate(expression, this.IsImmutable);
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isClientVariable = Nominate(expression, this.IsClosureExpression);
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}
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// Now rewrite given nomination functions
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FuncletizingVisitor visitor = new FuncletizingVisitor(this, isClientConstant, isClientVariable);
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Expression result = visitor.Visit(expression);
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recompileRequired = visitor.GetRecompileRequiredFunction();
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return result;
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}
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/// <summary>
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/// Replaces context parameter (e.g. 'ctx' in CompiledQuery.Compile(ctx => ctx.Products)) with constant
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/// containing the object context.
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/// </summary>
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private Expression ReplaceRootContextParameter(Expression expression)
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{
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if (null != _rootContextExpression)
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{
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return EntityExpressionVisitor.Visit(
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expression, (exp, baseVisit) =>
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exp == _rootContextParameter ? _rootContextExpression : baseVisit(exp));
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}
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else
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{
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return expression;
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}
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}
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/// <summary>
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/// Returns a function indicating whether the given expression and all of its children satisfy the
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/// 'localCriterion'.
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/// </summary>
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private static Func<Expression, bool> Nominate(Expression expression, Func<Expression, bool> localCriterion)
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{
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EntityUtil.CheckArgumentNull(localCriterion, "localCriterion");
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HashSet<Expression> candidates = new HashSet<Expression>();
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bool cannotBeNominated = false;
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Func<Expression, Func<Expression, Expression>, Expression> visit = (exp, baseVisit) =>
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{
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if (exp != null)
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{
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bool saveCannotBeNominated = cannotBeNominated;
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cannotBeNominated = false;
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baseVisit(exp);
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if (!cannotBeNominated)
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{
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// everyone below me can be nominated, so
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// see if this one can be also
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if (localCriterion(exp))
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{
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candidates.Add(exp);
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}
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else
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{
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cannotBeNominated = true;
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}
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}
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cannotBeNominated |= saveCannotBeNominated;
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}
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return exp;
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};
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EntityExpressionVisitor.Visit(expression, visit);
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return candidates.Contains;
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}
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private enum Mode
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{
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CompiledQueryLockdown,
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CompiledQueryEvaluation,
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ConventionalQuery,
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}
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/// <summary>
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/// Determines whether the node may be evaluated locally and whether
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/// it is a constant. Assumes that all children are also client expressions.
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/// </summary>
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private bool IsImmutable(Expression expression)
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{
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if (null == expression) { return false; }
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switch (expression.NodeType)
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{
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case ExpressionType.New:
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{
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// support construction of primitive types
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PrimitiveType primitiveType;
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if (!ClrProviderManifest.Instance.TryGetPrimitiveType(TypeSystem.GetNonNullableType(expression.Type),
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out primitiveType))
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{
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return false;
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}
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return true;
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}
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case ExpressionType.Constant:
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return true;
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case ExpressionType.NewArrayInit:
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// allow initialization of byte[] 'literals'
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return (typeof(byte[]) == expression.Type);
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case ExpressionType.Convert:
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return true;
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default:
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return false;
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}
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}
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/// <summary>
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/// Determines whether the node may be evaluated locally and whether
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/// it is a variable. Assumes that all children are also variable client expressions.
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/// </summary>
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private bool IsClosureExpression(Expression expression)
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{
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if (null == expression) { return false; }
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if (IsImmutable(expression)) { return true; }
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if (ExpressionType.MemberAccess == expression.NodeType)
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{
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MemberExpression member = (MemberExpression)expression;
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if (member.Member.MemberType == MemberTypes.Property)
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{
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return ExpressionConverter.CanFuncletizePropertyInfo((PropertyInfo)member.Member);
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}
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return true;
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}
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return false;
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}
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/// <summary>
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/// Determines whether the node may be evaluated as a compiled query parameter.
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/// Assumes that all children are also eligible compiled query parameters.
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/// </summary>
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private bool IsCompiledQueryParameterVariable(Expression expression)
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{
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if (null == expression) { return false; }
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if (IsClosureExpression(expression)) { return true; }
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if (ExpressionType.Parameter == expression.NodeType)
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{
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ParameterExpression parameter = (ParameterExpression)expression;
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return _compiledQueryParameters.Contains(parameter);
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}
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return false;
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}
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/// <summary>
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/// Determine whether the given CLR type is legal for an ObjectParameter or constant
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/// DbExpression.
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/// </summary>
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private bool TryGetTypeUsageForTerminal(Type type, out TypeUsage typeUsage)
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{
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EntityUtil.CheckArgumentNull(type, "type");
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if (_rootContext.Perspective.TryGetTypeByName(TypeSystem.GetNonNullableType(type).FullName,
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false, // bIgnoreCase
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out typeUsage) &&
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(TypeSemantics.IsScalarType(typeUsage)))
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{
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return true;
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}
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typeUsage = null;
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return false;
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}
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/// <summary>
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/// Creates the next available parameter name.
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/// </summary>
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internal string GenerateParameterName()
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{
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// To avoid collisions with user parameters (the full set is not
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// known at this time) we plug together an 'unlikely' prefix and
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// a number.
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return String.Format(CultureInfo.InvariantCulture, "{0}{1}",
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s_parameterPrefix,
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_parameterNumber++);
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}
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/// <summary>
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/// Walks the expression tree and replaces client-evaluable expressions with constants
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/// or QueryParameterExpressions.
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/// </summary>
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private sealed class FuncletizingVisitor : EntityExpressionVisitor
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{
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private readonly Funcletizer _funcletizer;
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private readonly Func<Expression, bool> _isClientConstant;
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private readonly Func<Expression, bool> _isClientVariable;
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private readonly List<Func<bool>> _recompileRequiredDelegates = new List<Func<bool>>();
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internal FuncletizingVisitor(
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Funcletizer funcletizer,
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Func<Expression, bool> isClientConstant,
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Func<Expression, bool> isClientVariable)
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{
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EntityUtil.CheckArgumentNull(funcletizer, "funcletizer");
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EntityUtil.CheckArgumentNull(isClientConstant, "isClientConstant");
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EntityUtil.CheckArgumentNull(isClientVariable, "isClientVariable");
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_funcletizer = funcletizer;
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_isClientConstant = isClientConstant;
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_isClientVariable = isClientVariable;
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}
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/// <summary>
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/// Returns a delegate indicating (when called) whether a change has been identified
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/// requiring a complete recompile of the query.
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/// </summary>
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internal Func<bool> GetRecompileRequiredFunction()
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{
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// assign list to local variable to avoid including the entire Funcletizer
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// class in the closure environment
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ReadOnlyCollection<Func<bool>> recompileRequiredDelegates = _recompileRequiredDelegates.AsReadOnly();
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return () => recompileRequiredDelegates.Any(d => d());
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}
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internal override Expression Visit(Expression exp)
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{
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if (exp != null)
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{
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if (!_funcletizer._linqExpressionStack.Add(exp))
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{
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// This expression is already in the stack.
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throw EntityUtil.InvalidOperation(Strings.ELinq_CycleDetected);
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}
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try
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{
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if (_isClientConstant(exp))
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{
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return InlineValue(exp, false);
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}
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else if (_isClientVariable(exp))
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{
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TypeUsage queryParameterType;
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if (_funcletizer.TryGetTypeUsageForTerminal(exp.Type, out queryParameterType))
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{
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DbParameterReferenceExpression parameterReference = queryParameterType.Parameter(_funcletizer.GenerateParameterName());
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return new QueryParameterExpression(parameterReference, exp, _funcletizer._compiledQueryParameters);
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}
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else if (_funcletizer.IsCompiledQuery)
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{
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throw InvalidCompiledQueryParameterException(exp);
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}
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else
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{
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return InlineValue(exp, true);
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}
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}
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return base.Visit(exp);
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}
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finally
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{
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_funcletizer._linqExpressionStack.Remove(exp);
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}
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}
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return base.Visit(exp);
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}
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private static NotSupportedException InvalidCompiledQueryParameterException(Expression expression)
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{
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ParameterExpression parameterExp;
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if (expression.NodeType == ExpressionType.Parameter)
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{
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parameterExp = (ParameterExpression)expression;
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}
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else
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{
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// If this is a simple query parameter (involving a single delegate parameter) report the
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// type of that parameter. Otherwise, report the type of the part of the parameter.
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HashSet<ParameterExpression> parameters = new HashSet<ParameterExpression>();
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EntityExpressionVisitor.Visit(expression, (exp, baseVisit) =>
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{
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if (null != exp && exp.NodeType == ExpressionType.Parameter)
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{
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parameters.Add((ParameterExpression)exp);
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}
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return baseVisit(exp);
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});
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if (parameters.Count != 1)
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{
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return EntityUtil.NotSupported(Strings.CompiledELinq_UnsupportedParameterTypes(expression.Type.FullName));
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}
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parameterExp = parameters.Single();
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}
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if (parameterExp.Type.Equals(expression.Type))
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{
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// If the expression type is the same as the parameter type, indicate that the parameter type is not valid.
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return EntityUtil.NotSupported(Strings.CompiledELinq_UnsupportedNamedParameterType(parameterExp.Name, parameterExp.Type.FullName));
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}
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else
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{
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// Otherwise, indicate that using the specified parameter to produce a value of the expression's type is not supported in compiled query
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return EntityUtil.NotSupported(Strings.CompiledELinq_UnsupportedNamedParameterUseAsType(parameterExp.Name, expression.Type.FullName));
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}
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}
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/// <summary>
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/// Compiles a delegate returning the value of the given expression.
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/// </summary>
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private Func<object> CompileExpression(Expression expression)
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{
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Func<object> func = Expression
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.Lambda<Func<object>>(TypeSystem.EnsureType(expression, typeof(object)))
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.Compile();
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return func;
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}
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/// <summary>
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/// Inlines a funcletizable expression. Queries and lambda expressions are expanded
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/// inline. All other values become simple constants.
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/// </summary>
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private Expression InlineValue(Expression expression, bool recompileOnChange)
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{
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Func<object> getValue = null;
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object value = null;
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if (expression.NodeType == ExpressionType.Constant)
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{
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value = ((ConstantExpression)expression).Value;
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}
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else
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{
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bool fastPath = false;
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//fastpath to process object query
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if (expression.NodeType == ExpressionType.Convert)
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{
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var ue = (UnaryExpression)expression;
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// The ObjectSet instance is wrapped inside Convert UnaryExpression in
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// ElinqQueryState.GetExpression(). The block below identifies such an
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// expression, makes sure the object query it contains is immutable and
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// extracts the reference to the object query.
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if (!recompileOnChange
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&& ue.Operand.NodeType == ExpressionType.Constant
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&& typeof(IQueryable).IsAssignableFrom(ue.Operand.Type))
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{
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value = ((ConstantExpression)ue.Operand).Value;
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fastPath = true;
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}
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}
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if (!fastPath)
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{
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getValue = CompileExpression(expression);
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value = getValue();
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}
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}
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Expression result = null;
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ObjectQuery inlineQuery = value as ObjectQuery;
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if (inlineQuery != null)
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{
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result = InlineObjectQuery(inlineQuery, expression.Type);
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}
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else
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{
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LambdaExpression lambda = value as LambdaExpression;
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if (null != lambda)
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{
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result = InlineExpression(Expression.Quote(lambda));
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}
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else
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{
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// everything else is just a constant...
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result = expression.NodeType == ExpressionType.Constant
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? expression
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: Expression.Constant(value, expression.Type);
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}
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}
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if (recompileOnChange)
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{
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AddRecompileRequiredDelegates(getValue, value);
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}
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return result;
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}
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private void AddRecompileRequiredDelegates(Func<object> getValue, object value)
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{
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// Build a delegate that returns true when the inline value has changed.
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// Outside of ObjectQuery, this amounts to a reference comparison.
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ObjectQuery originalQuery = value as ObjectQuery;
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if (null != originalQuery)
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{
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// For inline queries, we need to check merge options as well (it's mutable)
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MergeOption? originalMergeOption = originalQuery.QueryState.UserSpecifiedMergeOption;
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if (null == getValue)
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{
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_recompileRequiredDelegates.Add(() => originalQuery.QueryState.UserSpecifiedMergeOption != originalMergeOption);
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}
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else
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{
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_recompileRequiredDelegates.Add(() =>
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{
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ObjectQuery currentQuery = getValue() as ObjectQuery;
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return !object.ReferenceEquals(originalQuery, currentQuery) ||
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currentQuery.QueryState.UserSpecifiedMergeOption != originalMergeOption;
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});
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}
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}
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else if (null != getValue)
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{
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_recompileRequiredDelegates.Add(() => !object.ReferenceEquals(value, getValue()));
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}
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}
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/// <summary>
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/// Gets the appropriate LINQ expression for an inline ObjectQuery instance.
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/// </summary>
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private Expression InlineObjectQuery(ObjectQuery inlineQuery, Type expressionType)
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{
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EntityUtil.CheckArgumentNull(inlineQuery, "inlineQuery");
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|
Expression queryExpression;
|
|
if (_funcletizer._mode == Mode.CompiledQueryLockdown)
|
|
{
|
|
// In the lockdown phase, we don't chase down inline object queries because
|
|
// we don't yet know what the object context is supposed to be.
|
|
queryExpression = Expression.Constant(inlineQuery, expressionType);
|
|
}
|
|
else
|
|
{
|
|
if (!object.ReferenceEquals(_funcletizer._rootContext, inlineQuery.QueryState.ObjectContext))
|
|
{
|
|
throw EntityUtil.NotSupported(System.Data.Entity.Strings.ELinq_UnsupportedDifferentContexts);
|
|
}
|
|
|
|
queryExpression = inlineQuery.GetExpression();
|
|
|
|
// If it's not an entity-sql (terminal) query, recursively process
|
|
if (!(inlineQuery.QueryState is EntitySqlQueryState))
|
|
{
|
|
queryExpression = InlineExpression(queryExpression);
|
|
}
|
|
|
|
queryExpression = TypeSystem.EnsureType(queryExpression, expressionType);
|
|
}
|
|
|
|
return queryExpression;
|
|
}
|
|
|
|
private Expression InlineExpression(Expression exp)
|
|
{
|
|
Func<bool> inlineExpressionRequiresRecompile;
|
|
exp = _funcletizer.Funcletize(exp, out inlineExpressionRequiresRecompile);
|
|
if (!_funcletizer.IsCompiledQuery)
|
|
{
|
|
_recompileRequiredDelegates.Add(inlineExpressionRequiresRecompile);
|
|
}
|
|
return exp;
|
|
}
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// A LINQ expression corresponding to a query parameter.
|
|
/// </summary>
|
|
internal sealed class QueryParameterExpression : Expression
|
|
{
|
|
private readonly DbParameterReferenceExpression _parameterReference;
|
|
private readonly Type _type;
|
|
private readonly Expression _funcletizedExpression;
|
|
private readonly IEnumerable<ParameterExpression> _compiledQueryParameters;
|
|
private Delegate _cachedDelegate;
|
|
|
|
internal QueryParameterExpression(
|
|
DbParameterReferenceExpression parameterReference,
|
|
Expression funcletizedExpression,
|
|
IEnumerable<ParameterExpression> compiledQueryParameters)
|
|
{
|
|
EntityUtil.CheckArgumentNull(parameterReference, "parameterReference");
|
|
EntityUtil.CheckArgumentNull(funcletizedExpression, "funcletizedExpression");
|
|
_compiledQueryParameters = compiledQueryParameters ?? Enumerable.Empty<ParameterExpression>();
|
|
_parameterReference = parameterReference;
|
|
_type = funcletizedExpression.Type;
|
|
_funcletizedExpression = funcletizedExpression;
|
|
_cachedDelegate = null;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the current value of the parameter given (optional) compiled query arguments.
|
|
/// </summary>
|
|
internal object EvaluateParameter(object[] arguments)
|
|
{
|
|
if (_cachedDelegate == null)
|
|
{
|
|
if (_funcletizedExpression.NodeType == ExpressionType.Constant)
|
|
{
|
|
return ((ConstantExpression)_funcletizedExpression).Value;
|
|
}
|
|
ConstantExpression ce;
|
|
if (TryEvaluatePath(_funcletizedExpression, out ce))
|
|
{
|
|
return ce.Value;
|
|
}
|
|
}
|
|
|
|
try
|
|
{
|
|
if (_cachedDelegate == null)
|
|
{
|
|
// Get the Func<> type for the property evaluator
|
|
Type delegateType = TypeSystem.GetDelegateType(_compiledQueryParameters.Select(p => p.Type), _type);
|
|
|
|
// Now compile delegate for the funcletized expression
|
|
_cachedDelegate = Expression.Lambda(delegateType, _funcletizedExpression, _compiledQueryParameters).Compile();
|
|
}
|
|
return _cachedDelegate.DynamicInvoke(arguments);
|
|
}
|
|
catch (TargetInvocationException e)
|
|
{
|
|
throw e.InnerException;
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// Create QueryParameterExpression based on this one, but with the funcletized expression
|
|
/// wrapped by the given method
|
|
/// </summary>
|
|
/// <param name="method"></param>
|
|
/// <returns></returns>
|
|
internal QueryParameterExpression EscapeParameterForLike(Func<string, string> method)
|
|
{
|
|
Expression wrappedExpression = Expression.Invoke(Expression.Constant(method), this._funcletizedExpression);
|
|
return new QueryParameterExpression(this._parameterReference, wrappedExpression, this._compiledQueryParameters);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the parameter reference for the parameter.
|
|
/// </summary>
|
|
internal DbParameterReferenceExpression ParameterReference
|
|
{
|
|
get { return _parameterReference; }
|
|
}
|
|
|
|
public override Type Type
|
|
{
|
|
get { return _type; }
|
|
}
|
|
|
|
public override ExpressionType NodeType
|
|
{
|
|
get { return EntityExpressionVisitor.CustomExpression; }
|
|
}
|
|
|
|
private bool TryEvaluatePath(Expression expression, out ConstantExpression constantExpression)
|
|
{
|
|
MemberExpression me = expression as MemberExpression;
|
|
constantExpression = null;
|
|
if (me != null)
|
|
{
|
|
Stack<MemberExpression> stack = new Stack<MemberExpression>();
|
|
stack.Push(me);
|
|
while ((me = me.Expression as MemberExpression) != null)
|
|
{
|
|
stack.Push(me);
|
|
}
|
|
me = stack.Pop();
|
|
ConstantExpression ce = me.Expression as ConstantExpression;
|
|
if (ce != null)
|
|
{
|
|
object memberVal;
|
|
if (!TryGetFieldOrPropertyValue(me, ((ConstantExpression)me.Expression).Value, out memberVal))
|
|
{
|
|
return false;
|
|
}
|
|
if (stack.Count > 0)
|
|
{
|
|
foreach (var rec in stack)
|
|
{
|
|
if (!TryGetFieldOrPropertyValue(rec, memberVal, out memberVal))
|
|
{
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
constantExpression = Expression.Constant(memberVal, expression.Type);
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
private bool TryGetFieldOrPropertyValue(MemberExpression me, object instance, out object memberValue)
|
|
{
|
|
bool result = false;
|
|
memberValue = null;
|
|
|
|
try
|
|
{
|
|
if (me.Member.MemberType == MemberTypes.Field)
|
|
{
|
|
memberValue = ((FieldInfo)me.Member).GetValue(instance);
|
|
result = true;
|
|
}
|
|
else if (me.Member.MemberType == MemberTypes.Property)
|
|
{
|
|
memberValue = ((PropertyInfo)me.Member).GetValue(instance, null);
|
|
result = true;
|
|
}
|
|
return result;
|
|
}
|
|
catch (TargetInvocationException ex)
|
|
{
|
|
throw ex.InnerException;
|
|
}
|
|
}
|
|
}
|
|
}
|