public ServiceKey(Type serviceType, ServiceDefinition definition)
{
ServiceType = serviceType;
ImplementType = definition.GetImplementType();
}
private object GetServiceInstance(Type serviceType, ServiceDefinition serviceDefinition)
{
if (serviceDefinition.ImplementationInstance != null)
{
return(serviceDefinition.ImplementationInstance);
}
if (serviceDefinition.ImplementationFactory != null)
{
return(serviceDefinition.ImplementationFactory.Invoke(this));
}
var implementType = (serviceDefinition.ImplementType ?? serviceType);
if (implementType.IsInterface || implementType.IsAbstract)
{
throw new InvalidOperationException($"invalid service registered, serviceType: {serviceType.FullName}, implementType: {serviceDefinition.ImplementType}");
}
if (implementType.IsGenericType)
{
implementType = implementType.MakeGenericType(serviceType.GetGenericArguments());
}
var newFunc = CacheUtil.TypeNewFuncCache.GetOrAdd(implementType, (serviceContainer) =>
{
if (
CacheUtil.TypeEmptyConstructorFuncCache.TryGetValue(implementType, out var emptyFunc))
{
return(emptyFunc.Invoke());
}
var ctor = CacheUtil.TypeConstructorCache.GetOrAdd(implementType, t =>
{
var ctorInfos = t.GetConstructors(BindingFlags.Instance | BindingFlags.Public);
if (ctorInfos.Length == 0)
{
return(null);
}
ConstructorInfo ctorInfo;
if (ctorInfos.Length == 1)
{
ctorInfo = ctorInfos[0];
}
else
{
// TODO: try find best ctor
ctorInfo = ctorInfos
.OrderBy(_ => _.GetParameters().Length)
.First();
}
return(ctorInfo);
});
if (ctor == null)
{
throw new InvalidOperationException(
$"service {serviceType.FullName} does not have any public constructors");
}
var parameters = ctor.GetParameters();
if (parameters.Length == 0)
{
var func00 = Expression.Lambda <Func <object> >(Expression.New(ctor)).Compile();
CacheUtil.TypeEmptyConstructorFuncCache.TryAdd(implementType, func00);
return(func00.Invoke());
}
var ctorParams = new object[parameters.Length];
for (var index = 0; index < parameters.Length; index++)
{
var param = serviceContainer.GetService(parameters[index].ParameterType);
if (param == null && parameters[index].HasDefaultValue)
{
param = parameters[index].DefaultValue;
}
ctorParams[index] = param;
}
var func = CacheUtil.TypeConstructorFuncCache.GetOrAdd(implementType, t =>
{
if (!CacheUtil.TypeConstructorCache.TryGetValue(t, out var ctorInfo))
{
return(null);
}
var innerParameters = ctorInfo.GetParameters();
var parameterExpression = Expression.Parameter(typeof(object[]), "arguments"); // create parameter Expression
var argExpressions = new Expression[innerParameters.Length]; // array that will contains parameter expessions
for (var i = 0; i < innerParameters.Length; i++)
{
var indexedAccess = Expression.ArrayIndex(parameterExpression, Expression.Constant(i));
if (!innerParameters[i].ParameterType.IsClass) // check if parameter is a value type
{
var localVariable = Expression.Variable(innerParameters[i].ParameterType, "localVariable"); // if so - we should create local variable that will store paraameter value
var block = Expression.Block(new[] { localVariable },
Expression.IfThenElse(Expression.Equal(indexedAccess, Expression.Constant(null)),
Expression.Assign(localVariable, Expression.Default(innerParameters[i].ParameterType)),
Expression.Assign(localVariable, Expression.Convert(indexedAccess, innerParameters[i].ParameterType))
),
localVariable
);
argExpressions[i] = block;
}
else
{
argExpressions[i] = Expression.Convert(indexedAccess, innerParameters[i].ParameterType);
}
}
var newExpression = Expression.New(ctorInfo, argExpressions); // create expression that represents call to specified ctor with the specified arguments.
return(Expression.Lambda <Func <object[], object> >(newExpression, parameterExpression)
.Compile());
});
return(func.Invoke(ctorParams));
});
return(newFunc?.Invoke(this));
}
