/// <summary>
/// Returns the <see cref="ITarget"/> that should be compiled as the body of the delegate. If <see cref="BoundTarget"/>
/// is not null and its <see cref="ITarget.UseFallback"/> is false, then no binding is performed.
///
/// Otherwise, a suitable target is sought from the <paramref name="compileContext"/>. If not found, then
/// a <see cref="ResolvedTarget"/> is emitted with a fallback set to the <see cref="BoundTarget"/> if non-null,
/// meaning that the delegate will actually perform a late-bound resolve operation on the container on which it's
/// called.
/// </summary>
/// <param name="compileContext">The current compilation context, this is used to resolve the target to be bound.</param>
/// <returns>The target to be compiled as the body of the factory.</returns>
public ITarget Bind(ICompileContext compileContext)
{
if (BoundTarget != null && !BoundTarget.UseFallback)
{
return(BoundTarget);
}
return(compileContext.Fetch(ReturnType) ?? new ResolvedTarget(ReturnType, BoundTarget));
}
/// <summary>
/// Attempts to obtain the target that this <see cref="ResolvedTarget"/> resolves to for the given <see cref="ICompileContext"/>.
///
/// This function should be used by <see cref="ITargetCompiler"/> implementations when compiling factories which included this
/// instance, who wish to perform some form of up-front optimisations.
/// </summary>
/// <param name="context">The context from which a target is to be resolved.</param>
/// <returns>The target resolved by this target - could be the <see cref="FallbackTarget"/>, could be null.</returns>
/// <remarks>The target that is returned depends both on the <paramref name="context"/> passed and also whether
/// a <see cref="FallbackTarget"/> has been provided to this target.
/// </remarks>
public virtual ITarget Bind(ICompileContext context)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
var fromContext = context.Fetch(DeclaredType);
if (fromContext == null)
{
return(FallbackTarget); // might still be null of course
}
else if (fromContext.UseFallback)
{
return(FallbackTarget ?? fromContext);
}
return(fromContext);
}
