/// <summary>
/// Builds visitor for visiting <typeparamref name="TRootType"/> instance.
/// </summary>
/// <param name="depth">
/// The depth (level) of object graph that visitor will be able to visit.
/// Decreases build performance for large values.
/// </param>
/// <param name="guard">
/// If given, property guard will significantly decrease build time by avoiding circular references between property types.
/// If you wish to use it and intencionaly allow obvious property type cycles like hierarchy structures, use [VisitorHierarchy] attribute on property that forms hierarchy.
/// </param>
/// <param name="supportsCloning">
/// In order to support object cloning while visiting in IVisitor.Visit() method, many cloning expressions should be built, which is very costly time-wise.
/// To significantly decrease build time of visitors that don't need to clone objects, set this parameter to false (omits cloning expressions creation).
/// </param>
/// <returns>IVisitor for visiting instances of type <typeparamref name="TRootType"/></returns>
public IVisitor Build(int depth = Constants.MaxDepth, PropertyGuard guard = null, bool supportsCloning = true)
{
var visitor = new ElementVisitor <TRootType>(null, null, guard, supportsCloning);
Build(visitor, depth);
return(visitor);
}
private void Build(ElementVisitor visitor, int depth)
{
if (depth > Constants.MaxDepth)
{
throw new Exception(string.Format("Depth of visit cannot be more than {0}.", Constants.MaxDepth));
}
if (depth < 0)
{
return;
}
var currentNodeType = visitor.ElementType;
foreach (var property in currentNodeType.GetProperties(BindingFlags.Public | BindingFlags.Instance))
{
//Trying to find property match, first by name, owner type and property type. If not found, we will try only with property type.
var match = _properties.FirstOrDefault(p => p.ElementType == property.DeclaringType && p.PropertyName == property.Name && p.PropertyType == property.PropertyType);
if (match == null)
{
match = _properties.FirstOrDefault(p => p.ElementType == null && p.PropertyName == null && p.PropertyType == property.PropertyType);
}
if (match != null)
{
visitor.AddProperty(property.PropertyType, property.Name, match.GetNewValue);
}
if (Util.IsSimpleType(property.PropertyType))
{
continue;
}
//If property type is not primitive, we will assume we should add it as an element/collection, but after it's being built and turns out it's 'empty', we will remove it.
if (Util.IsDictionary(property.PropertyType))
{
var dictionaryItemType = Util.GetDictionaryItemsType(property.PropertyType);
if (Util.IsSimpleType(dictionaryItemType))
{
continue;
}
var isHierarchy = property.GetCustomAttribute <VisitorHierarchyAttribute>() != null;
var childVisitor = visitor.AddDictionary(dictionaryItemType, property.PropertyType, property.Name, isHierarchy);
if (childVisitor == null) //AddDirection() will return null in case of issues like circular reference.
{
continue;
}
Build(childVisitor, depth - 1);
if (!childVisitor.AnyElement && !childVisitor.AnyCollection && !childVisitor.AnyDictionary && !childVisitor.AnyProperty)
{
visitor.RemoveDictionary(property.PropertyType, property.Name);
}
}
else if (Util.IsGenericEnumerable(property.PropertyType) || Util.ImplementsGenericIEnumerable(property.PropertyType))
{
var collectionItemType = Util.GetCollectionItemsType(property.PropertyType);
if (Util.IsSimpleType(collectionItemType))
{
continue;
}
var isHierarchy = property.GetCustomAttribute <VisitorHierarchyAttribute>() != null;
var childVisitor = visitor.AddCollection(collectionItemType, property.PropertyType, property.Name, isHierarchy);
if (childVisitor == null) //AddCollection() will return null in case of issues like circular reference.
{
continue;
}
Build(childVisitor, depth - 1);
if (!childVisitor.AnyElement && !childVisitor.AnyCollection && !childVisitor.AnyProperty)
{
visitor.RemoveCollection(property.PropertyType, property.Name);
}
}
else
{
var isHierarchy = property.GetCustomAttribute <VisitorHierarchyAttribute>() != null;
var childVisitor = visitor.AddElement(property.PropertyType, property.Name, isHierarchy);
if (childVisitor == null) //AddElement() will return null in case of issues like circular reference.
{
continue;
}
Build(childVisitor, depth - 1);
if (!childVisitor.AnyElement && !childVisitor.AnyCollection && !childVisitor.AnyProperty)
{
visitor.RemoveElement(property.PropertyType, property.Name);
}
}
}
}
