Files
Umbraco-CMS/src/Umbraco.Core/Composing/ComposerGraph.cs

425 lines
16 KiB
C#

using System.Reflection;
using System.Text;
using Microsoft.Extensions.Logging;
using Umbraco.Cms.Core.Collections;
using Umbraco.Cms.Core.DependencyInjection;
namespace Umbraco.Cms.Core.Composing;
// note: this class is NOT thread-safe in any way
/// <summary>
/// Handles the composers.
/// </summary>
internal class ComposerGraph
{
private readonly IUmbracoBuilder _builder;
private readonly IEnumerable<Type> _composerTypes;
private readonly IEnumerable<Attribute> _enableDisableAttributes;
private readonly ILogger<ComposerGraph> _logger;
/// <summary>
/// Initializes a new instance of the <see cref="ComposerGraph" /> class.
/// </summary>
/// <param name="builder">The composition.</param>
/// <param name="composerTypes">The <see cref="IComposer" /> types.</param>
/// <param name="enableDisableAttributes">
/// The <see cref="EnableComposerAttribute" /> and/or
/// <see cref="DisableComposerAttribute" /> attributes.
/// </param>
/// <param name="logger">The logger.</param>
/// <exception cref="ArgumentNullException">
/// composition
/// or
/// composerTypes
/// or
/// enableDisableAttributes
/// or
/// logger
/// </exception>
public ComposerGraph(IUmbracoBuilder builder, IEnumerable<Type> composerTypes, IEnumerable<Attribute> enableDisableAttributes, ILogger<ComposerGraph> logger)
{
_builder = builder ?? throw new ArgumentNullException(nameof(builder));
_composerTypes = composerTypes ?? throw new ArgumentNullException(nameof(composerTypes));
_enableDisableAttributes =
enableDisableAttributes ?? throw new ArgumentNullException(nameof(enableDisableAttributes));
_logger = logger ?? throw new ArgumentNullException(nameof(logger));
}
/// <summary>
/// Instantiates and composes the composers.
/// </summary>
public void Compose()
{
// make sure it is there
_builder.WithCollectionBuilder<ComponentCollectionBuilder>();
IEnumerable<Type> orderedComposerTypes = PrepareComposerTypes();
foreach (IComposer composer in InstantiateComposers(orderedComposerTypes))
{
composer.Compose(_builder);
}
}
internal static string GetComposersReport(Dictionary<Type, List<Type>?> requirements)
{
var text = new StringBuilder();
text.AppendLine("Composers & Dependencies:");
text.AppendLine(" < compose before");
text.AppendLine(" > compose after");
text.AppendLine(" : implements");
text.AppendLine(" = depends");
text.AppendLine();
bool HasReq(IEnumerable<Type> types, Type type)
{
return types.Any(x => type.IsAssignableFrom(x) && !x.IsInterface);
}
foreach (KeyValuePair<Type, List<Type>?> kvp in requirements)
{
Type type = kvp.Key;
text.AppendLine(type.FullName);
foreach (ComposeAfterAttribute attribute in type.GetCustomAttributes<ComposeAfterAttribute>())
{
var weak = !(attribute.RequiredType.IsInterface ? attribute.Weak == false : attribute.Weak != true);
text.AppendLine(" > " + attribute.RequiredType +
(weak ? " (weak" : " (strong") +
(HasReq(requirements.Keys, attribute.RequiredType) ? ", found" : ", missing") + ")");
}
foreach (ComposeBeforeAttribute attribute in type.GetCustomAttributes<ComposeBeforeAttribute>())
{
text.AppendLine(" < " + attribute.RequiringType);
}
foreach (Type i in type.GetInterfaces())
{
text.AppendLine(" : " + i.FullName);
}
if (kvp.Value != null)
{
foreach (Type t in kvp.Value)
{
text.AppendLine(" = " + t);
}
}
text.AppendLine();
}
text.AppendLine("/");
text.AppendLine();
return text.ToString();
}
internal IEnumerable<Type> PrepareComposerTypes()
{
Dictionary<Type, List<Type>?> requirements = GetRequirements();
// only for debugging, this is verbose
// _logger.Debug<ComposerGraph>(GetComposersReport(requirements));
IEnumerable<Type> sortedComposerTypes = SortComposers(requirements);
// bit verbose but should help for troubleshooting
// var text = "Ordered Composers: " + Environment.NewLine + string.Join(Environment.NewLine, sortedComposerTypes) + Environment.NewLine;
if (_logger.IsEnabled(Microsoft.Extensions.Logging.LogLevel.Debug))
{
_logger.LogDebug("Ordered Composers: {SortedComposerTypes}", sortedComposerTypes);
}
return sortedComposerTypes;
}
internal Dictionary<Type, List<Type>?> GetRequirements(bool throwOnMissing = true)
{
// create a list, remove those that cannot be enabled due to runtime level
var composerTypeList = _composerTypes.ToList();
// enable or disable composers
EnableDisableComposers(_enableDisableAttributes, composerTypeList);
static void GatherInterfaces<TAttribute>(Type type, Func<TAttribute, Type> getTypeInAttribute, HashSet<Type> iset, List<Type> set2)
where TAttribute : Attribute
{
foreach (TAttribute attribute in type.GetCustomAttributes<TAttribute>())
{
Type typeInAttribute = getTypeInAttribute(attribute);
if (typeInAttribute != null && // if the attribute references a type ...
typeInAttribute.IsInterface && // ... which is an interface ...
typeof(IComposer).IsAssignableFrom(typeInAttribute) && // ... which implements IComposer ...
!iset.Contains(typeInAttribute)) // ... which is not already in the list
{
// add it to the new list
iset.Add(typeInAttribute);
set2.Add(typeInAttribute);
// add all its interfaces implementing IComposer
foreach (Type i in typeInAttribute.GetInterfaces()
.Where(x => typeof(IComposer).IsAssignableFrom(x)))
{
iset.Add(i);
set2.Add(i);
}
}
}
}
// gather interfaces too
var interfaces = new HashSet<Type>(composerTypeList.SelectMany(x =>
x.GetInterfaces().Where(y => typeof(IComposer).IsAssignableFrom(y))));
composerTypeList.AddRange(interfaces);
List<Type> list1 = composerTypeList;
while (list1.Count > 0)
{
var list2 = new List<Type>();
foreach (Type t in list1)
{
GatherInterfaces<ComposeAfterAttribute>(t, a => a.RequiredType, interfaces, list2);
GatherInterfaces<ComposeBeforeAttribute>(t, a => a.RequiringType, interfaces, list2);
}
composerTypeList.AddRange(list2);
list1 = list2;
}
// sort the composers according to their dependencies
var requirements = new Dictionary<Type, List<Type>?>();
foreach (Type type in composerTypeList)
{
requirements[type] = null;
}
foreach (Type type in composerTypeList)
{
GatherRequirementsFromAfterAttribute(type, composerTypeList, requirements, throwOnMissing);
GatherRequirementsFromBeforeAttribute(type, composerTypeList, requirements);
}
return requirements;
}
internal IEnumerable<Type> SortComposers(Dictionary<Type, List<Type>?> requirements)
{
// sort composers
var graph = new TopoGraph<Type, KeyValuePair<Type, List<Type>?>>(kvp => kvp.Key, kvp => kvp.Value);
graph.AddItems(requirements);
List<Type> sortedComposerTypes;
try
{
sortedComposerTypes = graph.GetSortedItems().Select(x => x.Key).Where(x => !x.IsInterface).ToList();
}
catch (Exception e)
{
// in case of an error, force-dump everything to log
_logger.LogInformation("Composer Report:\r\n{ComposerReport}", GetComposersReport(requirements));
_logger.LogError(e, "Failed to sort composers.");
throw;
}
return sortedComposerTypes;
}
private static void EnableDisableComposers(IEnumerable<Attribute> enableDisableAttributes, ICollection<Type> types)
{
var enabled = new Dictionary<Type, EnableInfo>();
// process the enable/disable attributes
// these two attributes are *not* inherited and apply to *classes* only (not interfaces).
// remote declarations (when a composer enables/disables *another* composer)
// have priority over local declarations (when a composer disables itself) so that
// ppl can enable composers that, by default, are disabled.
// what happens in case of conflicting remote declarations is unspecified. more
// precisely, the last declaration to be processed wins, but the order of the
// declarations depends on the type finder and is unspecified.
void UpdateEnableInfo(Type composerType, int weight2, Dictionary<Type, EnableInfo> enabled2, bool value)
{
if (enabled.TryGetValue(composerType, out EnableInfo? enableInfo) == false)
{
enableInfo = enabled2[composerType] = new EnableInfo();
}
if (enableInfo.Weight > weight2)
{
return;
}
enableInfo.Enabled = value;
enableInfo.Weight = weight2;
}
foreach (EnableComposerAttribute attr in enableDisableAttributes.OfType<EnableComposerAttribute>())
{
Type type = attr.EnabledType;
UpdateEnableInfo(type, 2, enabled, true);
}
foreach (DisableComposerAttribute attr in enableDisableAttributes.OfType<DisableComposerAttribute>())
{
Type type = attr.DisabledType;
UpdateEnableInfo(type, 2, enabled, false);
}
foreach (Type composerType in types)
{
foreach (EnableAttribute attr in composerType.GetCustomAttributes<EnableAttribute>())
{
Type type = attr.EnabledType ?? composerType;
var weight = type == composerType ? 1 : 3;
UpdateEnableInfo(type, weight, enabled, true);
}
foreach (DisableAttribute attr in composerType.GetCustomAttributes<DisableAttribute>())
{
Type type = attr.DisabledType ?? composerType;
var weight = type == composerType ? 1 : 3;
UpdateEnableInfo(type, weight, enabled, false);
}
}
// remove composers that end up being disabled
foreach (KeyValuePair<Type, EnableInfo> kvp in enabled.Where(x => x.Value.Enabled == false))
{
types.Remove(kvp.Key);
}
}
private static void GatherRequirementsFromAfterAttribute(Type type, ICollection<Type> types, IDictionary<Type, List<Type>?> requirements, bool throwOnMissing = true)
{
// get 'require' attributes
// these attributes are *not* inherited because we want to "custom-inherit" for interfaces only
IEnumerable<ComposeAfterAttribute> afterAttributes = type
.GetInterfaces().SelectMany(x => x.GetCustomAttributes<ComposeAfterAttribute>()) // those marking interfaces
.Concat(type.GetCustomAttributes<ComposeAfterAttribute>()); // those marking the composer
// what happens in case of conflicting attributes (different strong/weak for same type) is not specified.
foreach (ComposeAfterAttribute attr in afterAttributes)
{
if (attr.RequiredType == type)
{
continue; // ignore self-requirements (+ exclude in implems, below)
}
// requiring an interface = require any enabled composer implementing that interface
// unless strong, and then require at least one enabled composer implementing that interface
if (attr.RequiredType.IsInterface)
{
var implems = types.Where(x => x != type && attr.RequiredType.IsAssignableFrom(x) && !x.IsInterface)
.ToList();
if (implems.Count > 0)
{
if (requirements[type] == null)
{
requirements[type] = new List<Type>();
}
requirements[type]!.AddRange(implems);
}
// if explicitly set to !weak, is strong, else is weak
else if (attr.Weak == false && throwOnMissing)
{
throw new Exception(
$"Broken composer dependency: {type.FullName} -> {attr.RequiredType.FullName}.");
}
}
// requiring a class = require that the composer is enabled
// unless weak, and then requires it if it is enabled
else
{
if (types.Contains(attr.RequiredType))
{
if (requirements[type] == null)
{
requirements[type] = new List<Type>();
}
requirements[type]!.Add(attr.RequiredType);
}
// if not explicitly set to weak, is strong
else if (attr.Weak != true && throwOnMissing)
{
throw new Exception(
$"Broken composer dependency: {type.FullName} -> {attr.RequiredType.FullName}.");
}
}
}
}
private static void GatherRequirementsFromBeforeAttribute(Type type, ICollection<Type> types, IDictionary<Type, List<Type>?> requirements)
{
// get 'required' attributes
// these attributes are *not* inherited because we want to "custom-inherit" for interfaces only
IEnumerable<ComposeBeforeAttribute> beforeAttributes = type
.GetInterfaces()
.SelectMany(x => x.GetCustomAttributes<ComposeBeforeAttribute>()) // those marking interfaces
.Concat(type.GetCustomAttributes<ComposeBeforeAttribute>()); // those marking the composer
foreach (ComposeBeforeAttribute attr in beforeAttributes)
{
if (attr.RequiringType == type)
{
continue; // ignore self-requirements (+ exclude in implems, below)
}
// required by an interface = by any enabled composer implementing this that interface
if (attr.RequiringType.IsInterface)
{
var implems = types.Where(x => x != type && attr.RequiringType.IsAssignableFrom(x) && !x.IsInterface)
.ToList();
foreach (Type implem in implems)
{
if (requirements[implem] == null)
{
requirements[implem] = new List<Type>();
}
requirements[implem]!.Add(type);
}
}
// required by a class
else
{
if (types.Contains(attr.RequiringType))
{
if (requirements[attr.RequiringType] == null)
{
requirements[attr.RequiringType] = new List<Type>();
}
requirements[attr.RequiringType]!.Add(type);
}
}
}
}
private static IEnumerable<IComposer> InstantiateComposers(IEnumerable<Type> types)
{
foreach (Type type in types)
{
ConstructorInfo? ctor = type.GetConstructor(Array.Empty<Type>());
if (ctor == null)
{
throw new InvalidOperationException(
$"Composer {type.FullName} does not have a parameter-less constructor.");
}
yield return (IComposer)ctor.Invoke(Array.Empty<object>());
}
}
private class EnableInfo
{
public bool Enabled { get; set; }
public int Weight { get; set; } = -1;
}
}