Code:
/ Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / Orcas / SP / ndp / fx / src / DataEntity / System / Data / Objects / ELinq / BindingContext.cs / 3 / BindingContext.cs
//---------------------------------------------------------------------- //// Copyright (c) Microsoft Corporation. All rights reserved. // // // @owner [....] //--------------------------------------------------------------------- using CqtExpression = System.Data.Common.CommandTrees.DbExpression; using LinqExpression = System.Linq.Expressions.Expression; using System.Linq.Expressions; using System.Collections.ObjectModel; using System.Linq; using System.Collections.Generic; using System.Data.Common.CommandTrees; using System.Data.Metadata.Edm; using System.Reflection; using System.Data.Common.EntitySql; using System.Diagnostics; using System.Data.Common; using System.Globalization; namespace System.Data.Objects.ELinq { ////// Class containing binding information for an expression converter (associating CQT bindings /// with LINQ lambda parameter) /// ////// Usage pattern: /// internal sealed class BindingContext { private readonly Binding _rootContextBinding; private readonly List/// BindingContext context = ...; /// /// // translate a "Where" lamba expression input.Where(i => i.X > 2); /// LambdaExpression whereLambda = ...; /// CqtExpression inputCqt = Translate(whereLambda.Arguments[1]); /// CqtExpression inputBinding = CreateExpressionBinding(inputCqt).Var; /// /// // push the scope defined by the parameter /// context.PushBindingScope(new KeyValuePair{ParameterExpression, CqtExpression}(whereLambda.Parameters[0], inputBinding)); /// /// // translate the expression in this context /// CqtExpression result = Translate(whereLambda.Expression); /// /// // pop the scope /// context.PopBindingScope(); ///
///_scopes; internal readonly ObjectContext ObjectContext; /// /// Initialize a new binding context /// internal BindingContext(ParameterExpression rootContextParameter, ObjectContext objectContext, CompiledQueryParameter [] compiledQueryParameters ) : this() { Debug.Assert(null != rootContextParameter && null != objectContext, "missing required args to BindingContext"); _rootContextBinding = new Binding(rootContextParameter, null); this.ObjectContext = objectContext; PushBindingScope(_rootContextBinding); foreach (var parameter in compiledQueryParameters) { Binding binding = new Binding(parameter.Expression, parameter.ParameterReference); PushBindingScope(binding); } } ////// Initialize a new binding context /// internal BindingContext() { _scopes = new List(); } /// /// Set up a new binding scope where parameter expressions map to their paired CQT expressions. /// /// Parameter/Expression bindings internal void PushBindingScope(params Binding[] bindings) { _scopes.Add(bindings); } ////// Removes a scope when leaving a particular sub-expression. /// ///Scope. internal void PopBindingScope() { _scopes.RemoveAt(_scopes.Count - 1); } internal bool TryGetBoundExpression(Expression linqExpression, out CqtExpression cqtExpression) { Binding binding; if (TryGetBinding(linqExpression, out binding)) { if (binding != _rootContextBinding) { cqtExpression = binding.CqtExpression; return true; } } cqtExpression = null; return false; } internal bool IsRootContextParameter(ParameterExpression parameter) { Binding binding; if (TryGetBinding(parameter, out binding)) { return _rootContextBinding == binding; } return false; } // Try to find a CQT expression that is the translation of a LINQ parameter. private bool TryGetBinding(Expression parameter, out Binding binding) { binding = null; // if there are no binding scopes, their can be no binding if (_scopes.Count == 0) { return false; } for (int i = _scopes.Count - 1; i >= 0; i--) { Binding[] scope = _scopes[i]; foreach (Binding scopeBinding in scope) { if (parameter == scopeBinding.LinqExpression) { binding = scopeBinding; return true; } } } // no match found return false; } } ////// Class describing a LINQ parameter and its bound expression. For instance, in /// /// products.Select(p => p.ID) /// /// the 'products' query is the bound expression, and 'p' is the parameter. /// internal sealed class Binding { internal Binding(Expression linqExpression, CqtExpression cqtExpression) { LinqExpression = linqExpression; CqtExpression = cqtExpression; } internal readonly Expression LinqExpression; internal readonly CqtExpression CqtExpression; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. //---------------------------------------------------------------------- //// Copyright (c) Microsoft Corporation. All rights reserved. // // // @owner [....] //--------------------------------------------------------------------- using CqtExpression = System.Data.Common.CommandTrees.DbExpression; using LinqExpression = System.Linq.Expressions.Expression; using System.Linq.Expressions; using System.Collections.ObjectModel; using System.Linq; using System.Collections.Generic; using System.Data.Common.CommandTrees; using System.Data.Metadata.Edm; using System.Reflection; using System.Data.Common.EntitySql; using System.Diagnostics; using System.Data.Common; using System.Globalization; namespace System.Data.Objects.ELinq { ////// Class containing binding information for an expression converter (associating CQT bindings /// with LINQ lambda parameter) /// ////// Usage pattern: /// internal sealed class BindingContext { private readonly Binding _rootContextBinding; private readonly List/// BindingContext context = ...; /// /// // translate a "Where" lamba expression input.Where(i => i.X > 2); /// LambdaExpression whereLambda = ...; /// CqtExpression inputCqt = Translate(whereLambda.Arguments[1]); /// CqtExpression inputBinding = CreateExpressionBinding(inputCqt).Var; /// /// // push the scope defined by the parameter /// context.PushBindingScope(new KeyValuePair{ParameterExpression, CqtExpression}(whereLambda.Parameters[0], inputBinding)); /// /// // translate the expression in this context /// CqtExpression result = Translate(whereLambda.Expression); /// /// // pop the scope /// context.PopBindingScope(); ///
///_scopes; internal readonly ObjectContext ObjectContext; /// /// Initialize a new binding context /// internal BindingContext(ParameterExpression rootContextParameter, ObjectContext objectContext, CompiledQueryParameter [] compiledQueryParameters ) : this() { Debug.Assert(null != rootContextParameter && null != objectContext, "missing required args to BindingContext"); _rootContextBinding = new Binding(rootContextParameter, null); this.ObjectContext = objectContext; PushBindingScope(_rootContextBinding); foreach (var parameter in compiledQueryParameters) { Binding binding = new Binding(parameter.Expression, parameter.ParameterReference); PushBindingScope(binding); } } ////// Initialize a new binding context /// internal BindingContext() { _scopes = new List(); } /// /// Set up a new binding scope where parameter expressions map to their paired CQT expressions. /// /// Parameter/Expression bindings internal void PushBindingScope(params Binding[] bindings) { _scopes.Add(bindings); } ////// Removes a scope when leaving a particular sub-expression. /// ///Scope. internal void PopBindingScope() { _scopes.RemoveAt(_scopes.Count - 1); } internal bool TryGetBoundExpression(Expression linqExpression, out CqtExpression cqtExpression) { Binding binding; if (TryGetBinding(linqExpression, out binding)) { if (binding != _rootContextBinding) { cqtExpression = binding.CqtExpression; return true; } } cqtExpression = null; return false; } internal bool IsRootContextParameter(ParameterExpression parameter) { Binding binding; if (TryGetBinding(parameter, out binding)) { return _rootContextBinding == binding; } return false; } // Try to find a CQT expression that is the translation of a LINQ parameter. private bool TryGetBinding(Expression parameter, out Binding binding) { binding = null; // if there are no binding scopes, their can be no binding if (_scopes.Count == 0) { return false; } for (int i = _scopes.Count - 1; i >= 0; i--) { Binding[] scope = _scopes[i]; foreach (Binding scopeBinding in scope) { if (parameter == scopeBinding.LinqExpression) { binding = scopeBinding; return true; } } } // no match found return false; } } ////// Class describing a LINQ parameter and its bound expression. For instance, in /// /// products.Select(p => p.ID) /// /// the 'products' query is the bound expression, and 'p' is the parameter. /// internal sealed class Binding { internal Binding(Expression linqExpression, CqtExpression cqtExpression) { LinqExpression = linqExpression; CqtExpression = cqtExpression; } internal readonly Expression LinqExpression; internal readonly CqtExpression CqtExpression; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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