public Expression Build(Expression provider)
{
return(Expression.Call(
provider,
CaptureDisposableMethodInfo,
_service.Build(provider)));
}
private static Func <ServiceProvider, object> CompileCallSite(IServiceCallSite callSite)
{
var providerExpression = Expression.Parameter(typeof(ServiceProvider), "provider");
var lambdaExpression = Expression.Lambda <Func <ServiceProvider, object> >(
callSite.Build(providerExpression),
providerExpression);
return(lambdaExpression.Compile());
}
public virtual Expression Build(Expression providerExpression)
{
var keyExpression = Expression.Constant(
_key,
typeof(IService));
var resolvedExpression = Expression.Variable(typeof(object), "resolved");
var resolvedServicesExpression = Expression.Field(
providerExpression,
"_resolvedServices");
var tryGetValueExpression = Expression.Call(
resolvedServicesExpression,
TryGetValueMethodInfo,
keyExpression,
resolvedExpression);
var captureDisposableExpression = Expression.Assign(
resolvedExpression,
Expression.Call(
providerExpression,
CaptureDisposableMethodInfo,
_serviceCallSite.Build(providerExpression)));
var addValueExpression = Expression.Call(
resolvedServicesExpression,
AddMethodInfo,
keyExpression,
resolvedExpression);
var blockExpression = Expression.Block(
typeof(object),
new[] { resolvedExpression },
Expression.IfThen(
Expression.Not(tryGetValueExpression),
Expression.Block(captureDisposableExpression, addValueExpression)),
resolvedExpression);
return(Lock(providerExpression, blockExpression));
}
internal static Func <ServiceProvider, object> RealizeService(ServiceTable table, Type serviceType, IServiceCallSite callSite)
{
var callCount = 0;
return(provider =>
{
if (Interlocked.Increment(ref callCount) == 2)
{
Task.Run(() =>
{
var providerExpression = Expression.Parameter(typeof(ServiceProvider), "provider");
var lambdaExpression = Expression.Lambda <Func <ServiceProvider, object> >(
callSite.Build(providerExpression),
providerExpression);
table.RealizedServices[serviceType] = lambdaExpression.Compile();
});
}
return callSite.Invoke(provider);
});
}
private static Func<ServiceProvider, object> CompileCallSite(IServiceCallSite callSite)
{
var providerExpression = Expression.Parameter(typeof(ServiceProvider), "provider");
var lambdaExpression = Expression.Lambda<Func<ServiceProvider, object>>(
callSite.Build(providerExpression),
providerExpression);
return lambdaExpression.Compile();
}
public object GetService(Type serviceType)
{
Func <ServiceProvider, object> serviceAccessor;
if (this.RealizedServices.TryGetValue(serviceType, out serviceAccessor))
{
return(serviceAccessor(this));
}
IServiceCallSite serviceCallSite = this.GetServiceCallSite(serviceType, new HashSet <Type>());
if (null != serviceCallSite)
{
var providerExpression = Expression.Parameter(typeof(ServiceProvider), "provider");
this.RealizedServices[serviceType] = Expression.Lambda <Func <ServiceProvider, object> >(serviceCallSite.Build(providerExpression), providerExpression).Compile();
return(serviceCallSite.Invoke(this));
}
this.RealizedServices[serviceType] = _ => null;
return(null);
}
