// Returns
// (ParentType p) => dc.GetTable<ObjectType>().Where(...)
// (ParentType p) => dc.GetTable<ObjectType>().Where(...).DefaultIfEmpty
public static LambdaExpression CreateAssociationQueryLambda(ExpressionBuilder builder, AccessorMember onMember, AssociationDescriptor association,
Type parentOriginalType,
Type parentType,
Type objectType, bool inline, bool enforceDefault,
List <LoadWithInfo[]>?loadWith, out bool isLeft)
{
var dataContextConstant = Expression.Constant(builder.DataContext, builder.DataContext.GetType());
// We are trying to keep fast cache hit behaviour, so cache check should be added only if needed
//
bool shouldAddCacheCheck = false;
bool cacheCheckAdded = false;
LambdaExpression?definedQueryMethod = null;
if (association.HasQueryMethod())
{
// here we tell for Expression Comparer to compare optimized Association expressions
//
definedQueryMethod = (LambdaExpression)builder.AddQueryableMemberAccessors(onMember, builder.DataContext, (mi, dc) =>
{
var queryLambda = association.GetQueryMethod(parentType, objectType) ?? throw new InvalidOperationException();
var optimizationContext = new ExpressionTreeOptimizationContext(dc);
var optimizedExpr = optimizationContext.ExposeExpression(queryLambda);
optimizedExpr = optimizationContext.ExpandQueryableMethods(optimizedExpr);
return(optimizedExpr);
});
cacheCheckAdded = true;
var parameterMatch = new Dictionary <ParameterExpression, Expression>();
if (onMember.Arguments == null)
{
if (definedQueryMethod.Parameters.Count > 1 && typeof(IDataContext).IsSameOrParentOf(definedQueryMethod.Parameters[1].Type))
{
parameterMatch.Add(definedQueryMethod.Parameters[1], dataContextConstant);
}
}
else
{
var definedCount = definedQueryMethod.Parameters.Count;
var argumentsCount = onMember.Arguments.Count;
var diff = definedCount - argumentsCount;
for (int i = definedCount - 1; i >= diff; i--)
{
parameterMatch.Add(definedQueryMethod.Parameters[i], onMember.Arguments[i - diff]);
}
}
var body = definedQueryMethod.Body.Transform(parameterMatch, static (parameterMatch, e) =>
// Returns
// (ParentType p) => dc.GetTable<ObjectType>().Where(...)
// (ParentType p) => dc.GetTable<ObjectType>().Where(...).DefaultIfEmpty
public static LambdaExpression CreateAssociationQueryLambda(ExpressionBuilder builder, AccessorMember onMember, AssociationDescriptor association,
Type parentOriginalType,
Type parentType,
Type objectType, bool inline, bool enforceDefault,
List <LoadWithInfo[]>?loadWith, out bool isLeft)
{
var dataContextConstant = Expression.Constant(builder.DataContext, builder.DataContext.GetType());
// We are trying to keep fast cache hit behaviour, so cache check should be added only if needed
//
bool shouldAddCacheCheck = false;
bool cacheCheckAdded = false;
LambdaExpression?definedQueryMethod = null;
if (association.HasQueryMethod())
{
// here we tell for Expression Comparer to compare optimized Association expressions
//
definedQueryMethod = (LambdaExpression)builder.AddQueryableMemberAccessors((association, parentType, objectType), onMember, builder.DataContext, static (context, mi, dc) =>
// Returns
// (ParentType p) => dc.GetTable<ObjectType>().Where(...)
// (ParentType p) => dc.GetTable<ObjectType>().Where(...).DefaultIfEmpty
public static LambdaExpression CreateAssociationQueryLambda(ExpressionBuilder builder, AccessorMember onMember, AssociationDescriptor association,
Type parentOriginalType,
Type parentType,
Type objectType, bool inline, bool enforceDefault,
List <LoadWithInfo[]>?loadWith, out bool isLeft)
{
var dataContextConstant = Expression.Constant(builder.DataContext, builder.DataContext.GetType());
// We are trying to keep fast cache hit behaviour, so cache check should be added only if needed
//
bool shouldAddCacheCheck = false;
bool cacheCheckAdded = false;
LambdaExpression?definedQueryMethod = null;
if (association.HasQueryMethod())
{
// here we tell for Expression Comparer to compare optimized Association expressions
//
definedQueryMethod = (LambdaExpression)builder.AddQueryableMemberAccessors(onMember, builder.DataContext, (mi, dc) =>
{
var queryLambda = association.GetQueryMethod(parentType, objectType) ?? throw new InvalidOperationException();
var optimizationContext = new ExpressionTreeOptimizationContext(dc);
var optimizedExpr = optimizationContext.ExposeExpression(queryLambda);
optimizedExpr = optimizationContext.ExpandQueryableMethods(optimizedExpr);
optimizedExpr = optimizedExpr.OptimizeExpression() !;
return(optimizedExpr);
});
cacheCheckAdded = true;
var parameterMatch = new Dictionary <ParameterExpression, Expression>();
if (onMember.Arguments == null)
{
if (definedQueryMethod.Parameters.Count > 1 && typeof(IDataContext).IsSameOrParentOf(definedQueryMethod.Parameters[1].Type))
{
parameterMatch.Add(definedQueryMethod.Parameters[1], dataContextConstant);
}
}
else
{
var definedCount = definedQueryMethod.Parameters.Count;
var argumentsCount = onMember.Arguments.Count;
var diff = definedCount - argumentsCount;
for (int i = definedCount - 1; i >= diff; i--)
{
parameterMatch.Add(definedQueryMethod.Parameters[i], onMember.Arguments[i - diff]);
}
}
var body = definedQueryMethod.Body.Transform(e =>
{
if (e.NodeType == ExpressionType.Parameter &&
parameterMatch.TryGetValue((ParameterExpression)e, out var newExpression))
{
return(newExpression);
}
return(e);
});
definedQueryMethod = Expression.Lambda(body, definedQueryMethod.Parameters[0]);
}
var shouldAddDefaultIfEmpty = enforceDefault;
if (definedQueryMethod == null)
{
var parentParam = Expression.Parameter(parentType, "parent");
var childParam = Expression.Parameter(objectType, association.AliasName);
var parentAccessor = TypeAccessor.GetAccessor(parentType);
var childAccessor = TypeAccessor.GetAccessor(objectType);
Expression?predicate = null;
for (var i = 0; i < association.ThisKey.Length; i++)
{
var parentName = association.ThisKey[i];
var parentMember = parentAccessor.Members.Find(m => m.MemberInfo.Name == parentName);
if (parentMember == null)
{
throw new LinqException("Association key '{0}' not found for type '{1}.", parentName,
parentType);
}
var childName = association.OtherKey[i];
var childMember = childAccessor.Members.Find(m => m.MemberInfo.Name == childName);
if (childMember == null)
{
throw new LinqException("Association key '{0}' not found for type '{1}.", childName,
objectType);
}
var current = ExpressionBuilder.Equal(builder.MappingSchema,
Expression.MakeMemberAccess(parentParam, parentMember.MemberInfo),
Expression.MakeMemberAccess(childParam, childMember.MemberInfo));
predicate = predicate == null ? current : Expression.AndAlso(predicate, current);
}
var expressionPredicate = association.GetPredicate(parentType, objectType);
if (expressionPredicate != null)
{
shouldAddDefaultIfEmpty = true;
shouldAddCacheCheck = true;
var replacedBody = expressionPredicate.GetBody(parentParam, childParam);
predicate = predicate == null ? replacedBody : Expression.AndAlso(predicate, replacedBody);
}
if (predicate == null)
{
throw new LinqException("Can not generate Association predicate");
}
if (inline && !shouldAddDefaultIfEmpty)
{
var ed = builder.MappingSchema.GetEntityDescriptor(objectType);
if (ed.QueryFilterFunc != null)
{
shouldAddDefaultIfEmpty = true;
shouldAddCacheCheck = true;
}
}
var queryParam = Expression.Call(Methods.LinqToDB.GetTable.MakeGenericMethod(objectType), dataContextConstant);
var filterLambda = Expression.Lambda(predicate, childParam);
Expression body = Expression.Call(Methods.Queryable.Where.MakeGenericMethod(objectType), queryParam,
filterLambda);
definedQueryMethod = Expression.Lambda(body, parentParam);
}
else
{
shouldAddDefaultIfEmpty = true;
var bodyExpression = definedQueryMethod.Body.Unwrap();
if (bodyExpression.NodeType == ExpressionType.Call)
{
var mc = (MethodCallExpression)bodyExpression;
if (mc.IsSameGenericMethod(Methods.Queryable.DefaultIfEmpty, Methods.Queryable.DefaultIfEmptyValue))
{
shouldAddDefaultIfEmpty = false;
}
}
}
if (!cacheCheckAdded && shouldAddCacheCheck)
{
// here we tell for Expression Comparer to compare optimized Association expressions
//
var closureExpr = definedQueryMethod;
definedQueryMethod = (LambdaExpression)builder.AddQueryableMemberAccessors(onMember, builder.DataContext, (mi, dc) =>
{
var optimizationContext = new ExpressionTreeOptimizationContext(dc);
var optimizedExpr = optimizationContext.ExposeExpression(closureExpr);
optimizedExpr = optimizationContext.ExpandQueryableMethods(optimizedExpr);
optimizedExpr = optimizedExpr.OptimizeExpression() !;
return(optimizedExpr);
});
}
if (loadWith != null)
{
var associationLoadWith = GetLoadWith(loadWith)?
.FirstOrDefault(li => li.Info.MemberInfo == association.MemberInfo);
if (associationLoadWith != null &&
(associationLoadWith.Info.MemberFilter != null || associationLoadWith.Info.FilterFunc != null))
{
var body = definedQueryMethod.Body.Unwrap();
var memberFilter = associationLoadWith.Info.MemberFilter;
if (memberFilter != null)
{
var elementType = EagerLoading.GetEnumerableElementType(memberFilter.Parameters[0].Type,
builder.MappingSchema);
var filtered = Expression.Convert(body, typeof(IEnumerable <>).MakeGenericType(elementType));
var filterBody = memberFilter.GetBody(filtered);
body = Expression.Call(
Methods.Enumerable.AsQueryable.MakeGenericMethod(objectType), filterBody);
}
var loadWithFunc = associationLoadWith.Info.FilterFunc;
if (loadWithFunc != null)
{
loadWithFunc = loadWithFunc.Unwrap();
if (loadWithFunc is LambdaExpression lambda)
{
body = lambda.GetBody(body);
}
else
{
var filterDelegate = loadWithFunc.EvaluateExpression <Delegate>() ??
throw new LinqException("Cannot convert filter function '{loadWithFunc}' to Delegate.");
var arumentType = filterDelegate.GetType().GetGenericArguments()[0].GetGenericArguments()[0];
// check for fake argument q => q
if (arumentType.IsSameOrParentOf(objectType))
{
var query = ExpressionQueryImpl.CreateQuery(objectType, builder.DataContext, body);
var filtered = (IQueryable)filterDelegate.DynamicInvoke(query) !;
body = filtered.Expression;
}
}
}
definedQueryMethod = Expression.Lambda(body, definedQueryMethod.Parameters);
}
if (associationLoadWith?.NextLoadWith != null && associationLoadWith.NextLoadWith.Count > 0)
{
definedQueryMethod = (LambdaExpression)EnrichTablesWithLoadWith(builder.DataContext, definedQueryMethod, objectType,
associationLoadWith.NextLoadWith, builder.MappingSchema);
}
}
if (parentOriginalType != parentType)
{
// add discriminator filter
var ed = builder.MappingSchema.GetEntityDescriptor(parentOriginalType);
foreach (var inheritanceMapping in ed.InheritanceMapping)
{
if (inheritanceMapping.Type == parentType)
{
var objParam = Expression.Parameter(objectType, "o");
var filterLambda = Expression.Lambda(ExpressionBuilder.Equal(builder.MappingSchema,
Expression.MakeMemberAccess(definedQueryMethod.Parameters[0], inheritanceMapping.Discriminator.MemberInfo),
Expression.Constant(inheritanceMapping.Code)), objParam);
var body = definedQueryMethod.Body.Unwrap();
body = Expression.Call(Methods.Queryable.Where.MakeGenericMethod(objectType),
body, filterLambda);
definedQueryMethod = Expression.Lambda(body, definedQueryMethod.Parameters);
shouldAddDefaultIfEmpty = true;
break;
}
}
}
if (inline && shouldAddDefaultIfEmpty)
{
var body = definedQueryMethod.Body.Unwrap();
body = Expression.Call(Methods.Queryable.DefaultIfEmpty.MakeGenericMethod(objectType), body);
definedQueryMethod = Expression.Lambda(body, definedQueryMethod.Parameters);
isLeft = true;
}
else
{
isLeft = false;
}
definedQueryMethod = (LambdaExpression)builder.ConvertExpressionTree(definedQueryMethod);
definedQueryMethod = (LambdaExpression)builder.ConvertExpression(definedQueryMethod);
definedQueryMethod = (LambdaExpression)definedQueryMethod.OptimizeExpression() !;
return(definedQueryMethod);
}