private Expression CreateCollectionInitializer(LambdaScope lambdaScope, PropertyInfo collectionProperty, Type elementType, QueryLayer layer,
LambdaScopeFactory lambdaScopeFactory)
{
MemberExpression propertyExpression = Expression.Property(lambdaScope.Accessor, collectionProperty);
var builder = new QueryableBuilder(propertyExpression, elementType, typeof(Enumerable), _nameFactory, _resourceFactory, _resourceContextProvider,
_entityModel, lambdaScopeFactory);
Expression layerExpression = builder.ApplyQuery(layer);
// Earlier versions of EF Core 3.x failed to understand `query.ToHashSet()`, so we emit `new HashSet(query)` instead.
// Interestingly, EF Core 5 RC1 fails to understand `new HashSet(query)`, so we emit `query.ToHashSet()` instead.
// https://github.com/dotnet/efcore/issues/22902
if (EntityFrameworkCoreSupport.Version.Major < 5)
{
Type enumerableOfElementType = typeof(IEnumerable <>).MakeGenericType(elementType);
Type typedCollection = CollectionConverter.ToConcreteCollectionType(collectionProperty.PropertyType);
ConstructorInfo typedCollectionConstructor = typedCollection.GetConstructor(enumerableOfElementType.AsArray());
if (typedCollectionConstructor == null)
{
throw new InvalidOperationException($"Constructor on '{typedCollection.Name}' that accepts '{enumerableOfElementType.Name}' not found.");
}
return(Expression.New(typedCollectionConstructor, layerExpression));
}
string operationName = CollectionConverter.TypeCanContainHashSet(collectionProperty.PropertyType) ? "ToHashSet" : "ToList";
return(CopyCollectionExtensionMethodCall(layerExpression, operationName, elementType));
}
public override Expression VisitCollectionNotEmpty(CollectionNotEmptyExpression expression, Type argument)
{
Expression property = Visit(expression.TargetCollection, argument);
Type elementType = CollectionConverter.TryGetCollectionElementType(property.Type);
if (elementType == null)
{
throw new InvalidOperationException("Expression must be a collection.");
}
Expression predicate = null;
if (expression.Filter != null)
{
var hasManyThrough = expression.TargetCollection.Fields.Last() as HasManyThroughAttribute;
var lambdaScopeFactory = new LambdaScopeFactory(_nameFactory, hasManyThrough);
using LambdaScope lambdaScope = lambdaScopeFactory.CreateScope(elementType);
var builder = new WhereClauseBuilder(property, lambdaScope, typeof(Enumerable), _nameFactory);
predicate = builder.GetPredicateLambda(expression.Filter);
}
return(AnyExtensionMethodCall(elementType, property, predicate));
}
public QueryableBuilder(Expression source, Type elementType, Type extensionType, LambdaParameterNameFactory nameFactory,
IResourceFactory resourceFactory, IResourceContextProvider resourceContextProvider, IModel entityModel,
LambdaScopeFactory lambdaScopeFactory = null)
{
_source = source ?? throw new ArgumentNullException(nameof(source));
_elementType = elementType ?? throw new ArgumentNullException(nameof(elementType));
_extensionType = extensionType ?? throw new ArgumentNullException(nameof(extensionType));
_nameFactory = nameFactory ?? throw new ArgumentNullException(nameof(nameFactory));
_resourceFactory = resourceFactory ?? throw new ArgumentNullException(nameof(resourceFactory));
_resourceContextProvider = resourceContextProvider ?? throw new ArgumentNullException(nameof(resourceContextProvider));
_entityModel = entityModel ?? throw new ArgumentNullException(nameof(entityModel));
_lambdaScopeFactory = lambdaScopeFactory ?? new LambdaScopeFactory(_nameFactory);
}
private MemberAssignment CreatePropertyAssignment(PropertySelector selector, LambdaScope lambdaScope)
{
MemberExpression propertyAccess = Expression.Property(lambdaScope.Accessor, selector.Property);
Expression assignmentRightHandSide = propertyAccess;
if (selector.NextLayer != null)
{
HasManyThroughAttribute hasManyThrough = selector.OriginatingField as HasManyThroughAttribute;
var lambdaScopeFactory = new LambdaScopeFactory(_nameFactory, hasManyThrough);
assignmentRightHandSide = CreateAssignmentRightHandSideForLayer(selector.NextLayer, lambdaScope, propertyAccess,
selector.Property, lambdaScopeFactory);
}
return(Expression.Bind(selector.Property, assignmentRightHandSide));
}
public QueryableBuilder(Expression source, Type elementType, Type extensionType, LambdaParameterNameFactory nameFactory,
IResourceFactory resourceFactory, IResourceContextProvider resourceContextProvider, IModel entityModel,
LambdaScopeFactory lambdaScopeFactory = null)
{
ArgumentGuard.NotNull(source, nameof(source));
ArgumentGuard.NotNull(elementType, nameof(elementType));
ArgumentGuard.NotNull(extensionType, nameof(extensionType));
ArgumentGuard.NotNull(nameFactory, nameof(nameFactory));
ArgumentGuard.NotNull(resourceFactory, nameof(resourceFactory));
ArgumentGuard.NotNull(resourceContextProvider, nameof(resourceContextProvider));
ArgumentGuard.NotNull(entityModel, nameof(entityModel));
_source = source;
_elementType = elementType;
_extensionType = extensionType;
_nameFactory = nameFactory;
_resourceFactory = resourceFactory;
_resourceContextProvider = resourceContextProvider;
_entityModel = entityModel;
_lambdaScopeFactory = lambdaScopeFactory ?? new LambdaScopeFactory(_nameFactory);
}
private Expression CreateCollectionInitializer(LambdaScope lambdaScope, PropertyInfo collectionProperty,
Type elementType, QueryLayer layer, LambdaScopeFactory lambdaScopeFactory)
{
MemberExpression propertyExpression = Expression.Property(lambdaScope.Accessor, collectionProperty);
var builder = new QueryableBuilder(propertyExpression, elementType, typeof(Enumerable), _nameFactory,
_resourceFactory, _resourceContextProvider, _entityModel, lambdaScopeFactory);
Expression layerExpression = builder.ApplyQuery(layer);
Type enumerableOfElementType = typeof(IEnumerable <>).MakeGenericType(elementType);
Type typedCollection = TypeHelper.ToConcreteCollectionType(collectionProperty.PropertyType);
ConstructorInfo typedCollectionConstructor = typedCollection.GetConstructor(new[]
{
enumerableOfElementType
});
if (typedCollectionConstructor == null)
{
throw new Exception(
$"Constructor on '{typedCollection.Name}' that accepts '{enumerableOfElementType.Name}' not found.");
}
return(Expression.New(typedCollectionConstructor, layerExpression));
}
private Expression CreateAssignmentRightHandSideForLayer(QueryLayer layer, LambdaScope outerLambdaScope, MemberExpression propertyAccess,
PropertyInfo selectorPropertyInfo, LambdaScopeFactory lambdaScopeFactory)
{
Type collectionElementType = TypeHelper.TryGetCollectionElementType(selectorPropertyInfo.PropertyType);
Type bodyElementType = collectionElementType ?? selectorPropertyInfo.PropertyType;
if (collectionElementType != null)
{
return(CreateCollectionInitializer(outerLambdaScope, selectorPropertyInfo, bodyElementType, layer, lambdaScopeFactory));
}
if (layer.Projection == null || !layer.Projection.Any())
{
return(propertyAccess);
}
using var scope = lambdaScopeFactory.CreateScope(bodyElementType, propertyAccess);
return(CreateLambdaBodyInitializer(layer.Projection, layer.ResourceContext, scope, true));
}