/// <summary>
/// Initializes the proxy factory with the default values.
/// </summary>
public ProxyFactory()
{
// Use the forwarding proxy type by default
ProxyBuilder = new SerializableProxyBuilder();
InterfaceExtractor = new InterfaceExtractor();
Cache = new ProxyCache();
}
/// <summary>
/// Initializes the proxy factory with the default values.
/// </summary>
public ProxyFactory()
{
// Use the forwarding proxy type by default
ProxyBuilder = new SerializableProxyBuilder();
InterfaceExtractor = new InterfaceExtractor();
Cache = new ProxyCache();
}
public void InterfaceExtractorShouldReturnTheCorrectResults()
{
var baseType = typeof (SampleClass);
var extractor = new InterfaceExtractor();
var interfaces = new HashSet<Type>();
extractor.GetInterfaces(baseType, interfaces);
Assert.IsTrue(interfaces.Contains(typeof (ISampleService)));
Assert.IsTrue(interfaces.Contains(typeof (ISampleGenericService<int>)));
// The result list must only contain interface types
var nonInterfaceTypes = from t in interfaces
where !t.IsInterface
select t;
Assert.IsTrue(nonInterfaceTypes.Count() == 0);
}
public int GetHashCode(ProxyCacheEntry obj)
{
var extractor = new InterfaceExtractor();
var types = new HashSet <Type>(obj.Interfaces);
extractor.GetInterfaces(obj.BaseType, types);
// HACK: Calculate the hash code
// by XORing all the types together
var baseType = obj.BaseType;
var result = baseType.GetHashCode();
foreach (var type in types)
{
result ^= type.GetHashCode();
}
return(result);
}
/// <summary>
/// Creates a proxy type using the given
/// <paramref name="baseType"/> as the base class
/// and ensures that the proxy type implements the given
/// interface types.
/// </summary>
/// <param name="baseType">The base class from which the proxy type will be derived.</param>
/// <param name="baseInterfaces">The list of interfaces that the proxy will implement.</param>
/// <returns>A forwarding proxy.</returns>
public Type CreateProxyType(Type baseType, IEnumerable <Type> baseInterfaces)
{
// Reuse the cached results, if possible
Type[] originalInterfaces = baseInterfaces.ToArray();
if (Cache != null && Cache.Contains(baseType, originalInterfaces))
{
return(Cache.Get(baseType, originalInterfaces));
}
if (!baseType.IsPublic)
{
throw new ArgumentException("The proxy factory can only generate proxies from public base classes.",
"baseType");
}
bool hasNonPublicInterfaces = (from t in baseInterfaces
where t.IsNotPublic
select t).Count() > 0;
if (hasNonPublicInterfaces)
{
throw new ArgumentException("The proxy factory cannot generate proxies from non-public interfaces.",
"baseInterfaces");
}
#region Determine which interfaces need to be implemented
Type actualBaseType = baseType.IsInterface ? typeof(object) : baseType;
var interfaces = new HashSet <Type>(baseInterfaces);
// Move the base type into the list of interfaces
// if the user mistakenly entered
// an interface type as the base type
if (baseType.IsInterface)
{
interfaces.Add(baseType);
}
if (InterfaceExtractor != null)
{
// Get the interfaces for the base type
InterfaceExtractor.GetInterfaces(actualBaseType, interfaces);
Type[] targetList = interfaces.ToArray();
// Extract the inherited interfaces
foreach (Type type in targetList)
{
InterfaceExtractor.GetInterfaces(type, interfaces);
}
}
#endregion
#region Generate the assembly
string assemblyName = "LinFu.Proxy";
AssemblyDefinition assembly = AssemblyFactory.DefineAssembly(assemblyName, AssemblyKind.Dll);
ModuleDefinition mainModule = assembly.MainModule;
TypeReference importedBaseType = mainModule.Import(actualBaseType);
TypeAttributes attributes = TypeAttributes.AutoClass | TypeAttributes.Class |
TypeAttributes.Public | TypeAttributes.BeforeFieldInit;
#endregion
#region Initialize the proxy type
string guid = Guid.NewGuid().ToString().Replace("-", "");
string typeName = string.Format("{0}Proxy-{1}", baseType.Name, guid);
string namespaceName = "LinFu.Proxy";
TypeDefinition proxyType = mainModule.DefineClass(typeName, namespaceName,
attributes, importedBaseType);
proxyType.AddDefaultConstructor();
#endregion
if (ProxyBuilder == null)
{
throw new NullReferenceException("The 'ProxyBuilder' property cannot be null");
}
// Add the list of interfaces to the target type
foreach (Type interfaceType in interfaces)
{
if (!interfaceType.IsInterface)
{
continue;
}
TypeReference currentType = mainModule.Import(interfaceType);
proxyType.Interfaces.Add(currentType);
}
// Hand it off to the builder for construction
ProxyBuilder.Construct(actualBaseType, interfaces, mainModule, proxyType);
// Verify the assembly, if possible
if (Verifier != null)
{
Verifier.Verify(assembly);
}
#region Compile the results
Assembly compiledAssembly = assembly.ToAssembly();
IEnumerable <Type> types = null;
try
{
types = compiledAssembly.GetTypes();
}
catch (ReflectionTypeLoadException ex)
{
types = ex.Types;
}
Type result = (from t in types
where t != null && t.IsClass
select t).FirstOrDefault();
#endregion
// Cache the result
if (Cache != null)
{
Cache.Store(result, baseType, originalInterfaces);
}
return(result);
}
