public FunctionDescriptor(MethodInfo method, ITriggerAttribute trigger, FunctionParameterBindings parameterBindings, IUserQueryActivator activator)
{
this.Method = method;
this.Trigger = trigger;
this.ParameterBindings = parameterBindings;
this.Activator = activator;
}
public object[] Apply(FunctionParameterBindings parameterBindings)
{
var values = new object[parameterBindings.Arity];
for (int i = 0; i < values.Length; i++)
{
var binding = parameterBindings.GetBinding(i);
var value = FindValue(binding.ParameterType);
if (value == null)
{
values[i] = binding.DefaultValue;
}
else
{
values[i] = value;
}
}
return(values);
}
public static FunctionDescriptor Bind(MethodInfo m)
{
ITriggerAttribute trigger = null;
foreach (var triggerAttributeType in _triggerAttributeTypes)
{
var t = (ITriggerAttribute)m.GetCustomAttribute(triggerAttributeType, false);
if (t != null)
{
if (trigger != null)
{
throw new ApplicationException($"Function '{m.Name}' cannot have multiple triggers.");
}
trigger = t;
}
}
if (trigger == null)
{
return(null);
}
var parameters = m.GetParameters();
var parameterBindings = new FunctionParameterBindings(parameters.Length);
foreach (var p in parameters)
{
var pt = p.ParameterType;
if (parameterBindings.HasBinding(pt))
{
throw new ApplicationException($"Function '{m.Name}' parameter '{p.Name}' type '{pt.FullName}' has already been bound once (you should remove this parameter).");
}
parameterBindings.Bind(pt, p.Position);
}
var triggerRequiredParameterTypes = trigger.GetRequiredParameterTypes();
foreach (var triggerRequiredParameterType in triggerRequiredParameterTypes)
{
if (!parameterBindings.HasBinding(triggerRequiredParameterType))
{
throw new ApplicationException($"Function '{m.Name}' is missing required parameter of type '{triggerRequiredParameterType}' (you need to add a parameter of this type).");
}
}
var constructors = m.DeclaringType.GetConstructors();
if (!(constructors.Length == 1))
{
throw new ApplicationException($"Declaring type '{m.DeclaringType}' of function '{m.Name}' should have exactly 1 constructor.");
}
IUserQueryActivator activator;
var constructor = constructors[0];
var constructorParameters = constructor.GetParameters();
switch (constructorParameters.Length)
{
case 0:
{
activator = new UserQueryActivator(m.DeclaringType);
break; // ok, parameterless
}
case 1:
{
var constructorParameter0 = constructorParameters[0];
if (constructorParameter0.ParameterType == typeof(System.Data.IDbConnection))
{
activator = new UserQueryWithConnectionActivator(m.DeclaringType);
break; // ok, typed data context
}
goto default;
}
default:
throw new ApplicationException($"Declaring type '{m.DeclaringType}' of function '{m.Name}' has an unsupported constructor signature.");
}
var f = new FunctionDescriptor(m, trigger, parameterBindings, activator);
return(f);
}
