//Copyright 2010 Microsoft Corporation
//
//Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
//You may obtain a copy of the License at
//
//http://www.apache.org/licenses/LICENSE-2.0
//
//Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
//"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//See the License for the specific language governing permissions and limitations under the License.
namespace System.Data.Services.Client{
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq.Expressions;
#if ASTORIA_LIGHT
using System.Reflection;
using System.Security;
using System.Security.Permissions;
internal static class ExpressionHelpers
{
private static MethodInfo lambdaFunc;
internal static LambdaExpression CreateLambda(Expression body, params ParameterExpression[] parameters)
{
return CreateLambda(InferDelegateType(body, parameters), body, parameters);
}
internal static LambdaExpression CreateLambda(Type delegateType, Expression body, params ParameterExpression[] parameters)
{
var args = new[] { Expression.Parameter(typeof(Expression), "body"), Expression.Parameter(typeof(ParameterExpression[]), "parameters") };
var lambdaFactory = Expression.Lambda<Func<Expression, ParameterExpression[], LambdaExpression>>(
Expression.Call(GetLambdaFactoryMethod(delegateType), args), args
);
return lambdaFactory.Compile().Invoke(body, parameters);
}
private static Type InferDelegateType(Expression body, params ParameterExpression[] parameters)
{
bool isVoid = body.Type == typeof(void);
int length = (parameters == null) ? 0 : parameters.Length;
var typeArgs = new Type[length + (isVoid ? 0 : 1)];
for (int i = 0; i < length; i++)
{
typeArgs[i] = parameters[i].Type;
}
if (isVoid)
{
return Expression.GetActionType(typeArgs);
}
else
{
typeArgs[length] = body.Type;
return Expression.GetFuncType(typeArgs);
}
}
private static MethodInfo GetLambdaFactoryMethod(Type delegateType)
{
if (lambdaFunc == null)
{
lambdaFunc = new Func<Expression, ParameterExpression[], Expression<Action>>(Expression.Lambda<Action>).Method.GetGenericMethodDefinition();
}
return lambdaFunc.MakeGenericMethod(delegateType);
}
}
#endif
internal abstract class ExpressionVisitor
{
internal virtual Expression Visit(Expression exp)
{
if (exp == null)
{
return exp;
}
switch (exp.NodeType)
{
case ExpressionType.UnaryPlus:
case ExpressionType.Negate:
case ExpressionType.NegateChecked:
case ExpressionType.Not:
case ExpressionType.Convert:
case ExpressionType.ConvertChecked:
case ExpressionType.ArrayLength:
case ExpressionType.Quote:
case ExpressionType.TypeAs:
return this.VisitUnary((UnaryExpression)exp);
case ExpressionType.Add:
case ExpressionType.AddChecked:
case ExpressionType.Subtract:
case ExpressionType.SubtractChecked:
case ExpressionType.Multiply:
case ExpressionType.MultiplyChecked:
case ExpressionType.Divide:
case ExpressionType.Modulo:
case ExpressionType.And:
case ExpressionType.AndAlso:
case ExpressionType.Or:
case ExpressionType.OrElse:
case ExpressionType.LessThan:
case ExpressionType.LessThanOrEqual:
case ExpressionType.GreaterThan:
case ExpressionType.GreaterThanOrEqual:
case ExpressionType.Equal:
case ExpressionType.NotEqual:
case ExpressionType.Coalesce:
case ExpressionType.ArrayIndex:
case ExpressionType.RightShift:
case ExpressionType.LeftShift:
case ExpressionType.ExclusiveOr:
return this.VisitBinary((BinaryExpression)exp);
case ExpressionType.TypeIs:
return this.VisitTypeIs((TypeBinaryExpression)exp);
case ExpressionType.Conditional:
return this.VisitConditional((ConditionalExpression)exp);
case ExpressionType.Constant:
return this.VisitConstant((ConstantExpression)exp);
case ExpressionType.Parameter:
return this.VisitParameter((ParameterExpression)exp);
case ExpressionType.MemberAccess:
return this.VisitMemberAccess((MemberExpression)exp);
case ExpressionType.Call:
return this.VisitMethodCall((MethodCallExpression)exp);
case ExpressionType.Lambda:
return this.VisitLambda((LambdaExpression)exp);
case ExpressionType.New:
return this.VisitNew((NewExpression)exp);
case ExpressionType.NewArrayInit:
case ExpressionType.NewArrayBounds:
return this.VisitNewArray((NewArrayExpression)exp);
case ExpressionType.Invoke:
return this.VisitInvocation((InvocationExpression)exp);
case ExpressionType.MemberInit:
return this.VisitMemberInit((MemberInitExpression)exp);
case ExpressionType.ListInit:
return this.VisitListInit((ListInitExpression)exp);
default:
throw new NotSupportedException(Strings.ALinq_UnsupportedExpression(exp.NodeType.ToString()));
}
}
internal virtual MemberBinding VisitBinding(MemberBinding binding)
{
switch (binding.BindingType)
{
case MemberBindingType.Assignment:
return this.VisitMemberAssignment((MemberAssignment)binding);
case MemberBindingType.MemberBinding:
return this.VisitMemberMemberBinding((MemberMemberBinding)binding);
case MemberBindingType.ListBinding:
return this.VisitMemberListBinding((MemberListBinding)binding);
default:
throw new NotSupportedException(Strings.ALinq_UnsupportedExpression(binding.BindingType.ToString()));
}
}
internal virtual ElementInit VisitElementInitializer(ElementInit initializer)
{
ReadOnlyCollection<Expression> arguments = this.VisitExpressionList(initializer.Arguments);
if (arguments != initializer.Arguments)
{
return Expression.ElementInit(initializer.AddMethod, arguments);
}
return initializer;
}
internal virtual Expression VisitUnary(UnaryExpression u)
{
Expression operand = this.Visit(u.Operand);
if (operand != u.Operand)
{
return Expression.MakeUnary(u.NodeType, operand, u.Type, u.Method);
}
return u;
}
internal virtual Expression VisitBinary(BinaryExpression b)
{
Expression left = this.Visit(b.Left);
Expression right = this.Visit(b.Right);
Expression conversion = this.Visit(b.Conversion);
if (left != b.Left || right != b.Right || conversion != b.Conversion)
{
if (b.NodeType == ExpressionType.Coalesce && b.Conversion != null)
{
return Expression.Coalesce(left, right, conversion as LambdaExpression);
}
else
{
return Expression.MakeBinary(b.NodeType, left, right, b.IsLiftedToNull, b.Method);
}
}
return b;
}
internal virtual Expression VisitTypeIs(TypeBinaryExpression b)
{
Expression expr = this.Visit(b.Expression);
if (expr != b.Expression)
{
return Expression.TypeIs(expr, b.TypeOperand);
}
return b;
}
internal virtual Expression VisitConstant(ConstantExpression c)
{
return c;
}
internal virtual Expression VisitConditional(ConditionalExpression c)
{
Expression test = this.Visit(c.Test);
Expression iftrue = this.Visit(c.IfTrue);
Expression iffalse = this.Visit(c.IfFalse);
if (test != c.Test || iftrue != c.IfTrue || iffalse != c.IfFalse)
{
return Expression.Condition(test, iftrue, iffalse);
}
return c;
}
internal virtual Expression VisitParameter(ParameterExpression p)
{
return p;
}
internal virtual Expression VisitMemberAccess(MemberExpression m)
{
Expression exp = this.Visit(m.Expression);
if (exp != m.Expression)
{
return Expression.MakeMemberAccess(exp, m.Member);
}
return m;
}
internal virtual Expression VisitMethodCall(MethodCallExpression m)
{
Expression obj = this.Visit(m.Object);
IEnumerable<Expression> args = this.VisitExpressionList(m.Arguments);
if (obj != m.Object || args != m.Arguments)
{
return Expression.Call(obj, m.Method, args);
}
return m;
}
internal virtual ReadOnlyCollection<Expression> VisitExpressionList(ReadOnlyCollection<Expression> original)
{
List<Expression> list = null;
for (int i = 0, n = original.Count; i < n; i++)
{
Expression p = this.Visit(original[i]);
if (list != null)
{
list.Add(p);
}
else if (p != original[i])
{
list = new List<Expression>(n);
for (int j = 0; j < i; j++)
{
list.Add(original[j]);
}
list.Add(p);
}
}
if (list != null)
{
return new ReadOnlyCollection<Expression>(list);
}
return original;
}
internal virtual MemberAssignment VisitMemberAssignment(MemberAssignment assignment)
{
Expression e = this.Visit(assignment.Expression);
if (e != assignment.Expression)
{
return Expression.Bind(assignment.Member, e);
}
return assignment;
}
internal virtual MemberMemberBinding VisitMemberMemberBinding(MemberMemberBinding binding)
{
IEnumerable<MemberBinding> bindings = this.VisitBindingList(binding.Bindings);
if (bindings != binding.Bindings)
{
return Expression.MemberBind(binding.Member, bindings);
}
return binding;
}
internal virtual MemberListBinding VisitMemberListBinding(MemberListBinding binding)
{
IEnumerable<ElementInit> initializers = this.VisitElementInitializerList(binding.Initializers);
if (initializers != binding.Initializers)
{
return Expression.ListBind(binding.Member, initializers);
}
return binding;
}
internal virtual IEnumerable<MemberBinding> VisitBindingList(ReadOnlyCollection<MemberBinding> original)
{
List<MemberBinding> list = null;
for (int i = 0, n = original.Count; i < n; i++)
{
MemberBinding b = this.VisitBinding(original[i]);
if (list != null)
{
list.Add(b);
}
else if (b != original[i])
{
list = new List<MemberBinding>(n);
for (int j = 0; j < i; j++)
{
list.Add(original[j]);
}
list.Add(b);
}
}
if (list != null)
{
return list;
}
return original;
}
internal virtual IEnumerable<ElementInit> VisitElementInitializerList(ReadOnlyCollection<ElementInit> original)
{
List<ElementInit> list = null;
for (int i = 0, n = original.Count; i < n; i++)
{
ElementInit init = this.VisitElementInitializer(original[i]);
if (list != null)
{
list.Add(init);
}
else if (init != original[i])
{
list = new List<ElementInit>(n);
for (int j = 0; j < i; j++)
{
list.Add(original[j]);
}
list.Add(init);
}
}
if (list != null)
{
return list;
}
return original;
}
internal virtual Expression VisitLambda(LambdaExpression lambda)
{
Expression body = this.Visit(lambda.Body);
if (body != lambda.Body)
{
#if !ASTORIA_LIGHT
return Expression.Lambda(lambda.Type, body, lambda.Parameters);
#else
ParameterExpression[] parameters = new ParameterExpression[lambda.Parameters.Count];
lambda.Parameters.CopyTo(parameters, 0);
return ExpressionHelpers.CreateLambda(lambda.Type, body, parameters);
#endif
}
return lambda;
}
internal virtual NewExpression VisitNew(NewExpression nex)
{
IEnumerable<Expression> args = this.VisitExpressionList(nex.Arguments);
if (args != nex.Arguments)
{
if (nex.Members != null)
{
return Expression.New(nex.Constructor, args, nex.Members);
}
else
{
return Expression.New(nex.Constructor, args);
}
}
return nex;
}
internal virtual Expression VisitMemberInit(MemberInitExpression init)
{
NewExpression n = this.VisitNew(init.NewExpression);
IEnumerable<MemberBinding> bindings = this.VisitBindingList(init.Bindings);
if (n != init.NewExpression || bindings != init.Bindings)
{
return Expression.MemberInit(n, bindings);
}
return init;
}
internal virtual Expression VisitListInit(ListInitExpression init)
{
NewExpression n = this.VisitNew(init.NewExpression);
IEnumerable<ElementInit> initializers = this.VisitElementInitializerList(init.Initializers);
if (n != init.NewExpression || initializers != init.Initializers)
{
return Expression.ListInit(n, initializers);
}
return init;
}
internal virtual Expression VisitNewArray(NewArrayExpression na)
{
IEnumerable<Expression> exprs = this.VisitExpressionList(na.Expressions);
if (exprs != na.Expressions)
{
if (na.NodeType == ExpressionType.NewArrayInit)
{
return Expression.NewArrayInit(na.Type.GetElementType(), exprs);
}
else
{
return Expression.NewArrayBounds(na.Type.GetElementType(), exprs);
}
}
return na;
}
internal virtual Expression VisitInvocation(InvocationExpression iv)
{
IEnumerable<Expression> args = this.VisitExpressionList(iv.Arguments);
Expression expr = this.Visit(iv.Expression);
if (args != iv.Arguments || expr != iv.Expression)
{
return Expression.Invoke(expr, args);
}
return iv;
}
}
}
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