/// <summary>
/// Create service dependency graph from the specified array of service definitions.
/// </summary>
/// <param name="services">Array of services.</param>
/// <returns>
/// A <see cref="ServiceDependencyGraph"/> instance.
/// </returns>
/// <exception cref="System.ArgumentNullException">
/// If <paramref name="services"/> is <c>null</c>.
/// </exception>
public static ServiceDependencyGraph Create(IEnumerable <IServiceInstaller> services)
{
if (services == null)
{
throw new ArgumentNullException("services");
}
// Generate nodes along with mapping between definition and nodes.
var map = services.ToDictionary(x => x.TargetService, x => new Node(x));
// Form edges between nodes.
foreach (var node in map.Values)
{
foreach (var dependencyDescriptor in node.Installer.GetDependencies())
{
Node dependencyNode;
if (map.TryGetValue(dependencyDescriptor, out dependencyNode))
{
node.Targets.Add(dependencyNode);
dependencyNode.Inputs.Add(node);
}
}
}
var graph = new ServiceDependencyGraph();
graph.Nodes = new List <Node>(map.Values);
return(graph);
}
/// <summary>
/// Sort the specified services by their dependencies so that root-most services
/// occur first in resulting array.
/// </summary>
/// <param name="installers">Collection of service installers.</param>
/// <returns>
/// Results of sort; check the value of <see cref="Results.HasCircularDependency"/>
/// to determine whether sort was successful or unsuccessful.
/// </returns>
/// <exception cref="System.ArgumentNullException">
/// If <paramref name="installers"/> is <c>null</c>.
/// </exception>
public Results SortDependencies(IEnumerable <IServiceInstaller> installers)
{
if (installers == null)
{
throw new ArgumentNullException("installers");
}
var graph = ServiceDependencyGraph.Create(installers);
var graphNodes = new HashSet <ServiceDependencyGraph.Node>(graph.Nodes);
return(SortDependencies(graphNodes));
}