/// <summary>
/// Modifies the default constructor to initialize the "__initializedServices" field so that it can ensure that all
/// services called with the <see cref="IInitialize.Initialize"/> are initialized once per object lifetime.
/// </summary>
/// <param name="containerType">The container type.</param>
/// <param name="module">The module.</param>
/// <param name="fieldEmitter">The field builder.</param>
private void AddInitializationMap(TypeDefinition containerType, ModuleDefinition module, FieldBuilder fieldEmitter)
{
var initializationMapType = module.Import(typeof(Dictionary<int, int>));
var initializationMapField = new FieldDefinition("__initializedServices",
FieldAttributes.Private | FieldAttributes.InitOnly,
initializationMapType);
containerType.Fields.Add(initializationMapField);
var defaultConstructor = containerType.GetDefaultConstructor();
var body = defaultConstructor.Body;
// __initializedServices = new Dictionary<int, int>();
var il = body.GetILProcessor();
var dictionaryCtor = module.ImportConstructor<Dictionary<int, int>>();
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Newobj, dictionaryCtor);
il.Emit(OpCodes.Stfld, initializationMapField);
}
/// <summary>
/// Defines the nested constructors for the singleton type.
/// </summary>
/// <param name="module">The target module.</param>
/// <param name="nestedType">The nested type.</param>
/// <returns>The static singleton constructor.</returns>
private static MethodDefinition DefineNestedConstructors(ModuleDefinition module, TypeDefinition nestedType)
{
// Define the constructor for the nested t ype
nestedType.AddDefaultConstructor();
var defaultConstructor = nestedType.GetDefaultConstructor();
defaultConstructor.IsPublic = true;
var cctor = DefineStaticConstructor(module, nestedType);
cctor.IsPublic = true;
return cctor;
}
/// <summary>
/// Modifies the default constructor of a container type so that the jump labels used in the <see cref="IMicroContainer.GetInstance"/> implementation
/// will be precalculated every time the compiled container is instantiated.
/// </summary>
/// <param name="module">The target module.</param>
/// <param name="jumpTargetField">The field that holds the jump entries.</param>
/// <param name="targetType">The container type.</param>
/// <param name="getServiceHash">The hash calculation method.</param>
/// <param name="serviceMap">The collection that contains the current list of dependencies and their respective implementations.</param>
/// <param name="jumpTargets">A dictionary that maps dependencies to their respective label indexes.</param>
private static void AddJumpEntries(ModuleDefinition module, FieldDefinition jumpTargetField, TypeDefinition targetType, MethodReference getServiceHash, IDictionary<IDependency, IImplementation> serviceMap, IDictionary<IDependency, int> jumpTargets)
{
var defaultContainerConstructor = targetType.GetDefaultConstructor();
var body = defaultContainerConstructor.Body;
var il = body.GetILProcessor();
// Remove the last instruction and replace it with the jump entry
// initialization instructions
RemoveLastInstruction(body);
// Initialize the jump targets in the default container constructor
var getTypeFromHandleMethod = typeof(System.Type).GetMethod("GetTypeFromHandle", System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Static);
var getTypeFromHandle = module.Import(getTypeFromHandleMethod);
// __jumpTargets = new Dictionary<int, int>();
var dictionaryCtor = module.ImportConstructor<Dictionary<int, int>>();
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Newobj, dictionaryCtor);
il.Emit(OpCodes.Stfld, jumpTargetField);
var addMethod = module.ImportMethod<Dictionary<int, int>>("Add");
var index = 0;
foreach (var dependency in serviceMap.Keys)
{
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Ldfld, jumpTargetField);
var serviceType = dependency.ServiceType;
var serviceTypeRef = module.Import(serviceType);
// Push the service type
il.Emit(OpCodes.Ldtoken, serviceTypeRef);
il.Emit(OpCodes.Call, getTypeFromHandle);
// Push the service name
var pushName = dependency.ServiceName == null ? il.Create(OpCodes.Ldnull) : il.Create(OpCodes.Ldstr, dependency.ServiceName);
il.Append(pushName);
// Calculate the hash code using the service type and service name
il.Emit(OpCodes.Call, getServiceHash);
// Map the current dependency to the index
// that will be used in the GetInstance switch statement
jumpTargets[dependency] = index;
il.Emit(OpCodes.Ldc_I4, index++);
il.Emit(OpCodes.Callvirt, addMethod);
}
}