private static void AssertTransformation(
Expression <Func <TestClass, bool> > input,
Expression <Func <TestClass, bool> > output)
{
var visitor = new BooleanOptimizingExpressionVisitor();
var result = visitor.Visit(input.Body);
var hasher = new HashingExpressionVisitor();
hasher.Visit(result);
var inputHash = hasher.HashCode;
hasher.Reset();
hasher.Visit(output.Body);
var outputHash = hasher.HashCode;
Assert.AreEqual(inputHash, outputHash, "Output expression trees do not match");
}
private static void AssertTransformation <TResult>(
Expression <Func <IQueryable <MyClass1>, TResult> > input,
Expression <Func <IQueryable <MyClass1>, TResult> > output)
{
var visitor = new SelectorPushdownExpressionVisitor();
var result = visitor.Visit(input.Body);
var hasher = new HashingExpressionVisitor();
hasher.Visit(result);
var inputHash = hasher.HashCode;
hasher.Reset();
hasher.Visit(output.Body);
var outputHash = hasher.HashCode;
Assert.AreEqual(inputHash, outputHash, "Output expression trees do not match");
}
public void Hashing()
{
var hasher = new HashingExpressionVisitor();
// No closure
Expression <Func <string> > expr1 = () => "hello".ToString().Substring(0, 1);
Expression <Func <string> > expr2 = () => "hello".ToString().Substring(0, 1);
hasher.Visit(expr1);
var hashCode1 = hasher.HashCode;
hasher.Reset();
hasher.Visit(expr2);
var hashCode2 = hasher.HashCode;
hasher.Reset();
Assert.AreNotEqual(expr1, expr2);
Assert.AreEqual(hashCode1, hashCode2);
// Closure
Expression <Func <string> > CreateExpressionWithClosure(int value)
{
Expression <Func <string> > expression = () => "hello".ToString().Substring(value, 1);
return(expression);
}
var expr3 = CreateExpressionWithClosure(0);
var expr4 = CreateExpressionWithClosure(1);
hasher.Visit(expr3);
var hashCode3 = hasher.HashCode;
hasher.Reset();
hasher.Visit(expr4);
var hashCode4 = hasher.HashCode;
hasher.Reset();
Assert.AreNotEqual(expr3, expr4);
Assert.AreEqual(hashCode3, hashCode4);
// Partially evaluated
var evaluator = new PartialEvaluatingExpressionVisitor();
Expression <Func <string> > expr5 = () => "hello".ToString().Substring(0, 1);
var expr6 = CreateExpressionWithClosure(0);
hasher.Visit(evaluator.Visit(expr5));
var hashCode5 = hasher.HashCode;
hasher.Reset();
hasher.Visit(evaluator.Visit(expr6));
var hashCode6 = hasher.HashCode;
hasher.Reset();
Assert.AreNotEqual(expr5, expr6);
Assert.AreEqual(hashCode5, hashCode6);
}
private static void AssertTransformation <TResult>(
Expression <Func <IQueryable <MyClass1>, TResult> > input,
Expression <Func <IQueryable <MyClass1>, TResult> > output)
{
var myClass1KeyParameter = Expression.Parameter(typeof(MyClass1), "m1");
var myClass1KeyDescriptor
= new PrimaryKeyDescriptor
{
TargetType = typeof(MyClass1),
KeySelector
= Expression.Lambda(
Expression.MakeMemberAccess(
myClass1KeyParameter,
typeof(MyClass1).GetRuntimeProperty(nameof(MyClass1.Id))),
myClass1KeyParameter)
};
var myClass2KeyParameter = Expression.Parameter(typeof(MyClass2), "m2");
var myClass2KeyDescriptor
= new PrimaryKeyDescriptor
{
TargetType = typeof(MyClass2),
KeySelector
= Expression.Lambda(
Expression.MakeMemberAccess(
myClass2KeyParameter,
typeof(MyClass2).GetRuntimeProperty(nameof(MyClass2.Id))),
myClass2KeyParameter)
};
var myClass1NavigationDescriptor
= new NavigationDescriptor
{
Type = typeof(MyClass1),
Member = typeof(MyClass1).GetRuntimeProperty(nameof(MyClass1.Nav1)),
OuterKeySelector
= Expression.Lambda(
Expression.MakeMemberAccess(
myClass1KeyParameter,
typeof(MyClass1).GetRuntimeProperty(nameof(MyClass1.Nav1Id))),
myClass1KeyParameter),
InnerKeySelector = myClass2KeyDescriptor.KeySelector,
};
var visitor
= new KeyEqualityRewritingExpressionVisitor(
primaryKeyDescriptors: new[]
{
myClass1KeyDescriptor,
myClass2KeyDescriptor,
},
navigationDescriptors: new[]
{
myClass1NavigationDescriptor,
});
var result = visitor.Visit(input.Body);
var hasher = new HashingExpressionVisitor();
hasher.Visit(result);
var inputHash = hasher.HashCode;
hasher.Reset();
hasher.Visit(output.Body);
var outputHash = hasher.HashCode;
Assert.AreEqual(inputHash, outputHash, "Output expression trees do not match");
}