Code:
/ Dotnetfx_Win7_3.5.1 / Dotnetfx_Win7_3.5.1 / 3.5.1 / DEVDIV / depot / DevDiv / releases / Orcas / NetFXw7 / ndp / fx / src / DataWeb / Client / System / Data / Services / Client / ALinq / InputBinder.cs / 1 / InputBinder.cs
//---------------------------------------------------------------------- //// Copyright (c) Microsoft Corporation. All rights reserved. // //// Expression visitor that converts ParameterReference or (MemberAccess*)\ParameterReference expressions // into references to one or more ResourceSetExpressions. After processing, the specified expression tree // will contain InputReferenceExpressions instead of these parameter or parameter and property references. // // // @owner [....] //--------------------------------------------------------------------- namespace System.Data.Services.Client { using System; using System.Collections.Generic; using System.Text; using System.Linq; using System.Linq.Expressions; using System.Reflection; using System.Diagnostics; ////// Replaces references to resource sets - represented as either ParameterExpressions or one or more /// MemberExpressions over a ParameterExpression - with an appropriate InputReferenceExpression that /// indicates which resource set is referenced; effective 'binds' the argument expression to the /// resource sets that it references. /// internal sealed class InputBinder : DataServiceExpressionVisitor { ///Tracks which resource sets are referenced by the argument expression private readonly HashSetreferencedInputs = new HashSet (EqualityComparer .Default); /// Resource from which valid references must start; if no set with a transparent scope is present, only direct references to this resource will be rebound private readonly ResourceExpression input; ///The input resource, as a resource set (may be null if the input is actually a NavigationPropertySingletonExpression) private readonly ResourceSetExpression inputSet; ///The ParameterExpression that, if encountered, indicates a reference to the input resource set private readonly ParameterExpression inputParameter; ////// Constructs a new InputBinder based on the specified input resource set, which is represented by the specified ParameterExpression. /// /// The current input resource from which valid references must start /// The parameter that must be referenced in order to refer to the specified input resource set private InputBinder(ResourceExpression resource, ParameterExpression setReferenceParam) { this.input = resource; this.inputSet = resource as ResourceSetExpression; this.inputParameter = setReferenceParam; } ////// Replaces Lambda parameter references or transparent scope property accesses over those Lambda /// parameter references with /// The parameter to rebind /// /// The 'current input' resource set - either the root resource set or the /// rightmost set in the navigation chain. /// The Lambda parameter that represents a reference to the 'input' set /// A list that will be populated with the resource sets that were referenced by the rebound expression ///s to the appropriate corresponding /// s, based on the 'input' ResourceSetExpression to which the /// Lambda is logically applied and any enclosing transparent scope applied to that input resource set. /// /// The rebound version of internal static Expression Bind(Expression e, ResourceExpression currentInput, ParameterExpression inputParameter, Listwhere MemberExpression/ParameterExpressions that /// represent resource set references have been replaced with appropriate InputReferenceExpressions. /// referencedInputs) { Debug.Assert(e != null, "Expression cannot be null"); Debug.Assert(currentInput != null, "A current input resource set is required"); Debug.Assert(inputParameter != null, "The input lambda parameter is required"); Debug.Assert(referencedInputs != null, "The referenced inputs list is required"); InputBinder binder = new InputBinder(currentInput, inputParameter); e = binder.Visit(e); referencedInputs.AddRange(binder.referencedInputs); return e; } /// /// Resolves member accesses that represent transparent scope property accesses to the corresponding resource set, /// iff the input resource set is enclosed in a transparent scope and the specified MemberExpression represents /// such a property access. /// /// MemberExpression expression to visit ////// An InputReferenceExpression if the member access represents a transparent scope property /// access that can be resolved to a resource set in the path that produces the input resource set; /// otherwise the same MemberExpression is returned. /// internal override Expression VisitMemberAccess(MemberExpression m) { // If the current input resource set is not enclosed in a transparent scope, then this // MemberExpression cannot represent a valid transparent scope access based on the input parameter. if (this.inputSet == null || !this.inputSet.HasTransparentScope) { return base.VisitMemberAccess(m); } ParameterExpression innerParamRef = null; StacknestedAccesses = new Stack (); MemberExpression memberRef = m; while (memberRef != null && memberRef.Member.MemberType == MemberTypes.Property && memberRef.Expression != null) { nestedAccesses.Push((PropertyInfo)memberRef.Member); if (memberRef.Expression != null && memberRef.Expression.NodeType == ExpressionType.Parameter) { innerParamRef = (ParameterExpression)memberRef.Expression; } memberRef = memberRef.Expression as MemberExpression; } // Only continue if the inner non-MemberExpression is the input reference ParameterExpression and // at least one property reference is present - otherwise this cannot be a transparent scope access. if (innerParamRef == this.inputParameter && nestedAccesses.Count > 0) { ResourceExpression target = this.input; ResourceSetExpression targetSet = this.inputSet; Expression retExpr = null; while (nestedAccesses.Count > 0) { PropertyInfo currentProp = nestedAccesses.Pop(); if (retExpr == null && targetSet != null && targetSet.HasTransparentScope) { if (currentProp.Name.Equals(targetSet.TransparentScope.Accessor, StringComparison.Ordinal)) { retExpr = this.CreateReference(targetSet); } else { if (currentProp.Name.Equals(targetSet.TransparentScope.SourceAccessor, StringComparison.Ordinal)) { target = (ResourceExpression)targetSet.Source; targetSet = target as ResourceSetExpression; if (targetSet == null || !targetSet.HasTransparentScope) { retExpr = this.CreateReference(target); } } else { // The property reference is not to the resource set or it's source resource set. // This implies the transparent scope is not actually a transparent scope but a row constructor, // and is not supported. return m; } } } else { retExpr = Expression.Property(retExpr, currentProp); } } return retExpr; } return m; } /// /// Converts a parameter reference to the input resource set into an InputReferenceExpression, /// iff the parameter reference is to the parameter expression that represents the input resource set /// and the input resource set is not enclosed in a transparent scope. /// /// The parameter reference expression ////// An InputReferenceExpression if the parameter reference is to the input parameter; /// otherwise the same parameter reference expression /// internal override Expression VisitParameter(ParameterExpression p) { // If the input Resource Set is not enclosed in a transparent scope, // and the parameter reference is a reference to the Lambda parameter // that represents the input resource set, then return an InputReferenceExpression. if ((this.inputSet == null || !this.inputSet.HasTransparentScope) && p == this.inputParameter) { return this.CreateReference(this.input); } else { return base.VisitParameter(p); } } ////// Returns an /// The resource(set) for which a reference was found ///that references the specified resource set, /// and also adds the the resource set to the hashset of resource sets that were referenced by the /// expression that is being rebound. /// An InputReferenceExpression that represents a reference to the specified resource set private Expression CreateReference(ResourceExpression resource) { this.referencedInputs.Add(resource); return resource.CreateReference(); } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. //---------------------------------------------------------------------- //// Copyright (c) Microsoft Corporation. All rights reserved. // //// Expression visitor that converts ParameterReference or (MemberAccess*)\ParameterReference expressions // into references to one or more ResourceSetExpressions. After processing, the specified expression tree // will contain InputReferenceExpressions instead of these parameter or parameter and property references. // // // @owner [....] //--------------------------------------------------------------------- namespace System.Data.Services.Client { using System; using System.Collections.Generic; using System.Text; using System.Linq; using System.Linq.Expressions; using System.Reflection; using System.Diagnostics; ////// Replaces references to resource sets - represented as either ParameterExpressions or one or more /// MemberExpressions over a ParameterExpression - with an appropriate InputReferenceExpression that /// indicates which resource set is referenced; effective 'binds' the argument expression to the /// resource sets that it references. /// internal sealed class InputBinder : DataServiceExpressionVisitor { ///Tracks which resource sets are referenced by the argument expression private readonly HashSetreferencedInputs = new HashSet (EqualityComparer .Default); /// Resource from which valid references must start; if no set with a transparent scope is present, only direct references to this resource will be rebound private readonly ResourceExpression input; ///The input resource, as a resource set (may be null if the input is actually a NavigationPropertySingletonExpression) private readonly ResourceSetExpression inputSet; ///The ParameterExpression that, if encountered, indicates a reference to the input resource set private readonly ParameterExpression inputParameter; ////// Constructs a new InputBinder based on the specified input resource set, which is represented by the specified ParameterExpression. /// /// The current input resource from which valid references must start /// The parameter that must be referenced in order to refer to the specified input resource set private InputBinder(ResourceExpression resource, ParameterExpression setReferenceParam) { this.input = resource; this.inputSet = resource as ResourceSetExpression; this.inputParameter = setReferenceParam; } ////// Replaces Lambda parameter references or transparent scope property accesses over those Lambda /// parameter references with /// The parameter to rebind /// /// The 'current input' resource set - either the root resource set or the /// rightmost set in the navigation chain. /// The Lambda parameter that represents a reference to the 'input' set /// A list that will be populated with the resource sets that were referenced by the rebound expression ///s to the appropriate corresponding /// s, based on the 'input' ResourceSetExpression to which the /// Lambda is logically applied and any enclosing transparent scope applied to that input resource set. /// /// The rebound version of internal static Expression Bind(Expression e, ResourceExpression currentInput, ParameterExpression inputParameter, Listwhere MemberExpression/ParameterExpressions that /// represent resource set references have been replaced with appropriate InputReferenceExpressions. /// referencedInputs) { Debug.Assert(e != null, "Expression cannot be null"); Debug.Assert(currentInput != null, "A current input resource set is required"); Debug.Assert(inputParameter != null, "The input lambda parameter is required"); Debug.Assert(referencedInputs != null, "The referenced inputs list is required"); InputBinder binder = new InputBinder(currentInput, inputParameter); e = binder.Visit(e); referencedInputs.AddRange(binder.referencedInputs); return e; } /// /// Resolves member accesses that represent transparent scope property accesses to the corresponding resource set, /// iff the input resource set is enclosed in a transparent scope and the specified MemberExpression represents /// such a property access. /// /// MemberExpression expression to visit ////// An InputReferenceExpression if the member access represents a transparent scope property /// access that can be resolved to a resource set in the path that produces the input resource set; /// otherwise the same MemberExpression is returned. /// internal override Expression VisitMemberAccess(MemberExpression m) { // If the current input resource set is not enclosed in a transparent scope, then this // MemberExpression cannot represent a valid transparent scope access based on the input parameter. if (this.inputSet == null || !this.inputSet.HasTransparentScope) { return base.VisitMemberAccess(m); } ParameterExpression innerParamRef = null; StacknestedAccesses = new Stack (); MemberExpression memberRef = m; while (memberRef != null && memberRef.Member.MemberType == MemberTypes.Property && memberRef.Expression != null) { nestedAccesses.Push((PropertyInfo)memberRef.Member); if (memberRef.Expression != null && memberRef.Expression.NodeType == ExpressionType.Parameter) { innerParamRef = (ParameterExpression)memberRef.Expression; } memberRef = memberRef.Expression as MemberExpression; } // Only continue if the inner non-MemberExpression is the input reference ParameterExpression and // at least one property reference is present - otherwise this cannot be a transparent scope access. if (innerParamRef == this.inputParameter && nestedAccesses.Count > 0) { ResourceExpression target = this.input; ResourceSetExpression targetSet = this.inputSet; Expression retExpr = null; while (nestedAccesses.Count > 0) { PropertyInfo currentProp = nestedAccesses.Pop(); if (retExpr == null && targetSet != null && targetSet.HasTransparentScope) { if (currentProp.Name.Equals(targetSet.TransparentScope.Accessor, StringComparison.Ordinal)) { retExpr = this.CreateReference(targetSet); } else { if (currentProp.Name.Equals(targetSet.TransparentScope.SourceAccessor, StringComparison.Ordinal)) { target = (ResourceExpression)targetSet.Source; targetSet = target as ResourceSetExpression; if (targetSet == null || !targetSet.HasTransparentScope) { retExpr = this.CreateReference(target); } } else { // The property reference is not to the resource set or it's source resource set. // This implies the transparent scope is not actually a transparent scope but a row constructor, // and is not supported. return m; } } } else { retExpr = Expression.Property(retExpr, currentProp); } } return retExpr; } return m; } /// /// Converts a parameter reference to the input resource set into an InputReferenceExpression, /// iff the parameter reference is to the parameter expression that represents the input resource set /// and the input resource set is not enclosed in a transparent scope. /// /// The parameter reference expression ////// An InputReferenceExpression if the parameter reference is to the input parameter; /// otherwise the same parameter reference expression /// internal override Expression VisitParameter(ParameterExpression p) { // If the input Resource Set is not enclosed in a transparent scope, // and the parameter reference is a reference to the Lambda parameter // that represents the input resource set, then return an InputReferenceExpression. if ((this.inputSet == null || !this.inputSet.HasTransparentScope) && p == this.inputParameter) { return this.CreateReference(this.input); } else { return base.VisitParameter(p); } } ////// Returns an /// The resource(set) for which a reference was found ///that references the specified resource set, /// and also adds the the resource set to the hashset of resource sets that were referenced by the /// expression that is being rebound. /// An InputReferenceExpression that represents a reference to the specified resource set private Expression CreateReference(ResourceExpression resource) { this.referencedInputs.Add(resource); return resource.CreateReference(); } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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