private static void HandleFieldConstant(Set <UsedPropertyChain> container,
MemberExpression memberExpression,
ChildInformation child,
TraversalOptions options)
{
Func <object> constantObjectRetriever = CompileMemberExpression(memberExpression);
HandleFieldConstant(container, constantObjectRetriever, child, options);
}
private static void HandleFieldConstant(Set <UsedPropertyChain> container,
Func <object> constantObjectRetriever,
ChildInformation child,
TraversalOptions options)
{
INotifyPropertyChanged notifiable;
Func <object> targetRetriever;
if (child.Property != null)
{
//This occurs in case of expression like:
//React.To(() => recursive.PropertyA).Set(...);
//or with marker methods:
//React.To(() => recursive.TrackFields().PropertyA).Set(...);
notifiable = child.Property.GetCurrentParent();
targetRetriever = constantObjectRetriever;
}
else
{
//This case occurs, when a method is called on a tracked field, e.g.:
//React.To(() => recursive.TrackFields().GetInner().PropertyA).Set(...);
//The call to GetInner() breaks the chain and there is no tracked child
//for the 'recursive' object. However, this is still a viable case;
//if recursive is INPC, track all properties on it, otherwise track nothing.
Func <object> parentRetriever = constantObjectRetriever;
notifiable = parentRetriever() as INotifyPropertyChanged;
targetRetriever = parentRetriever;
}
if (notifiable != null && child.IsTrackable) //property and method children are trackable
{
//Do not allow fields here, because they cannot be tracked anyhow.
//string.Empty here as the property name does not mean all properties
//of the associated object will be tracked. It only means that associated
//object is stored in a field and changes to that field cannot be tracked,
//just because it's not a property. Thus, string.Empty indicates lack
//of any property name.
var chain = new UsedPropertyChain(notifiable, string.Empty, child.Property, options);
chain.TargetRetriever = targetRetriever;
container.Add(chain);
}
//Otherwise, track nothing
}
private static UsedSubproperty GetContinuationChainLink(
MemberExpression memberExpression,
ChildInformation child,
TraversalOptions options)
{
Func <INotifyPropertyChanged> parentRetriever =
CompileObjectFactoryExpressionINPC(memberExpression.Expression);
if (parentRetriever == null)
{
//This happens when parentMember refers to a non-observable collection
return(null);
}
var usedSub = new UsedSubproperty(memberExpression.Member.Name, parentRetriever,
child.Property, options);
usedSub.TargetRetriever = CompileMemberExpression(memberExpression);
return(usedSub);
}
/// <summary>
///
/// </summary>
/// <param name="container"></param>
/// <param name="expression"></param>
/// <param name="options"></param>
/// <param name="continuedChild">The sub-chain that might be broken by
/// a marker method call.</param>
private static void GetUsedProperties(Set <UsedPropertyChain> container,
Expression expression, ChildInformation continuedChild, TraversalOptions options)
{
if (expression == null)
{
return; //e.g. in case of static method calls object is null
}
var lambda = expression as LambdaExpression;
if (lambda != null)
{
GetUsedProperties(container, lambda.Body, continuedChild, options);
return;
}
var member = expression as MemberExpression;
if (member != null)
{
GetUsedProperties(container, member, continuedChild, options);
return;
}
if (expression is ConstantExpression)
{
//Not traceable, nothing to do / case handled elsewhere
return;
}
var binary = expression as BinaryExpression;
if (binary != null)
{
GetUsedProperties(container, binary.Left, continuedChild, options);
GetUsedProperties(container, binary.Right, continuedChild, options);
return;
}
var typeBinaryExpression = expression as TypeBinaryExpression;
if (typeBinaryExpression != null) //is operator
{
GetUsedProperties(container, typeBinaryExpression.Expression, continuedChild, options);
return;
}
var unary = expression as UnaryExpression;
if (unary != null)
{
GetUsedProperties(container, unary.Operand, continuedChild, options);
return;
}
if (expression is ParameterExpression)
{
//Presumably, we are within a nested lambda parameter block.
//Skip, just for now. If there's a nested lambda like "c=>c.property" it
//is pretty complicated to know when to update.
//TODO:
return;
}
var methodCall = expression as MethodCallExpression;
if (methodCall != null)
{
IEnumerable <Expression> arguments;
bool isMarkerMethod = CheckForMarkerMethodCalls(methodCall, ref options);
if (!isMarkerMethod) //required by expression logic
{
//ApplyMarkerCall(ObservableExpression.TrackLastChild, ref options);
//disallow continuation if it is not a marker method
continuedChild = ChildInformation.MethodBreak;
//take all arguments
arguments = methodCall.Arguments;
}
else
{
//Take only the first argument, which is the 'this' parameter
//of the (marker) extension method. Do *not* further process other
//arguments of marker methods, because they can be also expressions
//in general, but as for now their meaning is totally different than
//in React.To(...).
arguments = methodCall.Arguments.Take(1);
}
GetUsedProperties(container, methodCall.Object, continuedChild, options);
foreach (var arg in arguments)
{
GetUsedProperties(container, arg, continuedChild, options);
}
return;
}
var conditional = expression as ConditionalExpression;
if (conditional != null)
{
GetUsedProperties(container, conditional.Test, continuedChild, options);
GetUsedProperties(container, conditional.IfFalse, continuedChild, options);
GetUsedProperties(container, conditional.IfTrue, continuedChild, options);
return;
}
var invocation = expression as InvocationExpression;
if (invocation != null)
{
continuedChild = ChildInformation.MethodBreak;
GetUsedProperties(container, invocation.Expression, continuedChild, options);
foreach (var arg in invocation.Arguments)
{
GetUsedProperties(container, arg, continuedChild, options);
}
return;
}
//var newArray = expression as NewArrayExpression;
//if (newArray != null)
//{
// return;
//}
string msg = string.Format(
"Expressions of type {0} are not supported.", expression.GetType());
throw new NotSupportedException(msg);
}
private static void GetUsedProperties(Set <UsedPropertyChain> container,
MemberExpression memberExpression,
ChildInformation child,
TraversalOptions options)
{
if (memberExpression == null)
{
return;
}
MemberTypes memberType = memberExpression.Member.MemberType;
if (memberType != MemberTypes.Property)
{
if (memberType == MemberTypes.Field)
{
if (options.TrackFields)
{
var constant = memberExpression.Expression as ConstantExpression;
if (constant != null)
{
HandleFieldConstant(container, memberExpression, child, options);
return;
}
if (IsFieldChain(memberExpression) && child.IsTrackable)
{
//Occurs with a.b.c.A kind of expression, where
//the field chain is the leading part of the
//expression and the constant can be extracted from
//it. The constant is taken from evaluation of a.b.c
HandleFieldConstant(container, memberExpression, child, options);
return;
}
else
{
//Dead end. It happens, when a field occurs
//after a non-constant element, e.g. after
//a property reference as in 'A.B.field.C'
//'A.B' is not ConstantExpression and therefore,
//even with TrackFields on, the field cannot be
//tracked any further. However, the preceding
//part of the expression can and should be
//tracked.
//Break the chain (without continuation)
GetUsedProperties(container, memberExpression.Expression, ChildInformation.FieldBreak, options);
return;
}
}
else
{
//Break the chain (without continuation)
GetUsedProperties(container, memberExpression.Expression, ChildInformation.FieldBreak, options);
return;
}
}
throw new InvalidOperationException("Unhandled case. Revise the code");
}
var parentMember = memberExpression.Expression as MemberExpression;
if (parentMember != null)
{
UsedSubproperty usedSubProperty = GetContinuationChainLink(memberExpression, child, options);
var usedChild = new ChildInformation(usedSubProperty);
//Continue the chain
GetUsedProperties(container, parentMember, usedChild, options);
}
else
{
if (memberExpression.Expression is ParameterExpression)
{
//Presumably, we are within a nested lambda parameter block.
//Skip, just for now. If there's a nested lambda like "c=>c.property" it
//is pretty complicated to know when to update.
//TODO:
return;
}
var constant = memberExpression.Expression as ConstantExpression;
if (constant != null)
{
var notifiable = constant.Value as INotifyPropertyChanged;
if (notifiable != null)
{
string propertyName = memberExpression.Member.Name;
var chain = new UsedPropertyChain(notifiable, propertyName, child.Property, options);
chain.TargetRetriever = CompileMemberExpression(memberExpression);
container.Add(chain);
}
else
{
//Even now add a chain to the container. Fields are not traced, but their
//properties can be. This applies only to cases where a the left-hand part
//of an expression is a field or a field/constant chain.
HandleFieldConstant(container, memberExpression, child, options);
}
return;
}
else
{
UsedSubproperty usedSubProperty = GetContinuationChainLink(memberExpression, child, options);
var usedChild = new ChildInformation(usedSubProperty);
//This should break the notification chain or continue, if it's marker method.
GetUsedProperties(container, memberExpression.Expression, usedChild, options);
}
}
}
