/// <summary>
/// Checks if the registry contains an implementation of a given interface for a given
/// platform.
/// </summary>
/// <typeparam name="TInterface">The type of the interface needed.</typeparam>
/// <param name="platform">The platform for which the interface must be implemented.</param>
/// <returns>`true` if the interface is there, `false` otherwise.</returns>
public static bool Has <TInterface>(Platform platform)
where TInterface : class
{
Type ifaceType = typeof(TInterface);
var platformImpl = new PlatformImplementation(platform, ifaceType);
lock (s_implementations)
{
if (s_implementations.ContainsKey(platformImpl))
{
return(true);
}
}
return(s_defaultImplementations.ContainsKey(ifaceType));
}
private static void RegisterImplementationImplNoLock(Platform platform, Type ifaceType, object implementation)
{
var platformImpl = new PlatformImplementation(platform, ifaceType);
object prevImpl = null;
if (s_implementations.TryGetValue(platformImpl, out prevImpl))
{
if (object.ReferenceEquals(prevImpl, implementation))
{
return;
}
throw new InvalidOperationException($"There is already an implementation of interface {ifaceType} for platform {platform}. Cannot register {implementation.GetType().AssemblyQualifiedName}");
}
else
{
s_implementations.Add(platformImpl, implementation);
}
}
/// <summary>
/// Gets the implementation of a given interface for a given platform. If no implementation
/// was defined for that platform, returns the default implementation instead, if one was
/// defined. Does not throw an exception if no platform implementation is found.
/// </summary>
/// <typeparam name="TInterface">The type of the interface to get.</typeparam>
/// <param name="platform">The platform whose implementation is requested.</param>
/// <returns>The implementation of <typeparamref name="TInterface"/> for a given platform, or `null` if no such implementation or default implementation exists for that platform.</returns>
public static TInterface Query <TInterface>(Platform platform)
where TInterface : class
{
Type ifaceType = typeof(TInterface);
var platformImpl = new PlatformImplementation(platform, ifaceType);
object implObj = null;
lock (s_implementations)
{
if (s_implementations.TryGetValue(platformImpl, out implObj))
{
return((TInterface)implObj);
}
}
if (s_defaultImplementations.TryGetValue(ifaceType, out implObj))
{
return((TInterface)implObj);
}
else
{
return(null);
}
}
public PlatformImplementationDescriptor(PlatformImplementation impl, Type type)
{
Implementation = impl;
ConcreteType = type;
}
public static object GetImplementation(PlatformImplementation impl)
{
return(sImplementations.ContainsKey(impl) ? sImplementations[impl] : null);
}
public static void RegisterImplementation(PlatformImplementation impl, object inst)
{
sImplementations[impl] = inst;
}
public ImplementationOfAttribute(PlatformImplementation impl, string module)
{
Implementation = impl;
ParentModule = module;
}
