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Implement topological sorting using feature dependencies

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This commit is contained in:
Sipke Schoorstra 2022-08-14 19:38:58 +02:00
parent bce2be6314
commit faab394fc4
2 changed files with 45 additions and 45 deletions
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33
src/common/Elsa.Features/Extensions/EnumerableTopologicalSortExtensions.cs Normal file
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@ -0,0 +1,33 @@
namespace Elsa.Features.Extensions;
public static class EnumerableTopologicalSortExtensions
{
public static IEnumerable<T> TSort<T>(this IEnumerable<T> source, Func<T, IEnumerable<T>> dependencies, bool throwOnCycle = false)
{
var sorted = new List<T>();
var visited = new HashSet<T>();
foreach (var item in source)
Visit(item, visited, sorted, dependencies, throwOnCycle);
return sorted;
}
private static void Visit<T>(T item, ISet<T> visited, ICollection<T> sorted, Func<T, IEnumerable<T>> dependencies, bool throwOnCycle)
{
if (!visited.Contains(item))
{
visited.Add(item);
foreach (var dep in dependencies(item))
Visit(dep, visited, sorted, dependencies, throwOnCycle);
sorted.Add(item);
}
else
{
if (throwOnCycle && !sorted.Contains(item))
throw new Exception("Cyclic dependency found");
}
}
}

57
src/common/Elsa.Features/Implementations/Module.cs
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@ -1,5 +1,6 @@
using System.Reflection;
using Elsa.Features.Attributes;
using Elsa.Features.Extensions;
using Elsa.Features.Services;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
@ -21,18 +22,18 @@ public class Module : IModule
public IServiceCollection Services { get; }
public T Configure<T>(Action<T>? configure = default) where T : class, IFeature => Configure(serviceConfiguration => (T)Activator.CreateInstance(typeof(T), serviceConfiguration)!, configure);
public T Configure<T>(Action<T>? configure = default) where T : class, IFeature => Configure(module => (T)Activator.CreateInstance(typeof(T), module)!, configure);
public T Configure<T>(Func<IModule, T> factory, Action<T>? configure = default) where T : class, IFeature
{
if (_features.FirstOrDefault(x => x is T) is not T configurator)
if (_features.FirstOrDefault(x => x is T) is not T feature)
{
configurator = factory(this);
_features.Add(configurator);
feature = factory(this);
_features.Add(feature);
}
configure?.Invoke(configurator);
return configurator;
configure?.Invoke(feature);
return feature;
}
public IModule ConfigureHostedService<T>(int priority = 0)
@ -43,9 +44,10 @@ public class Module : IModule
public void Apply()
{
ResolveDependencies();
var featureTypes = _features.Select(x => x.GetType()).TSort(x => x.GetCustomAttributes<DependsOn>().Select(dependsOn => dependsOn.Type)).ToList();
var features = featureTypes.Select(featureType => _features.FirstOrDefault(x => x.GetType() == featureType) ?? (IFeature)Activator.CreateInstance(featureType, this)!).ToList();
foreach (var feature in _features)
foreach (var feature in features)
{
feature.Configure();
feature.ConfigureHostedServices();
@ -53,43 +55,8 @@ public class Module : IModule
foreach (var hostedServiceDescriptor in _hostedServiceDescriptors.OrderBy(x => x.Order))
Services.TryAddEnumerable(ServiceDescriptor.Singleton(typeof(IHostedService), hostedServiceDescriptor.HostedServiceType));
foreach (var feature in _features)
{
foreach (var feature in features)
feature.Apply();
}
}
private void ResolveDependencies()
{
var resolvedDependencyTypes = new HashSet<Type>();
foreach (var configurator in _features.ToList())
ResolveDependencies(configurator, resolvedDependencyTypes);
}
private void ResolveDependencies(IFeature feature, ISet<Type> resolvedDependencyTypes)
{
var dependencyTypes = feature.GetType().GetCustomAttributes<DependsOn>().Select(x => x.Type).ToHashSet();
dependencyTypes = dependencyTypes.Except(resolvedDependencyTypes).ToHashSet();
foreach (var type in dependencyTypes)
{
var dependencyConfigurator = AddConfigurator(type);
resolvedDependencyTypes.Add(type);
ResolveDependencies(dependencyConfigurator, resolvedDependencyTypes);
}
}
private IFeature AddConfigurator(Type type)
{
var configurator = _features.FirstOrDefault(x => x.GetType() == type);
if (configurator != null)
return configurator;
configurator = (IFeature)Activator.CreateInstance(type, this)!;
_features.Add(configurator);
return configurator;
}
}