public override IEnumerable <ExportDescriptorPromise> GetExportDescriptors(
CompositionContract contract, DependencyAccessor descriptorAccessor)
{
if (_logger.IsEnabled(LogLevel.Debug))
{
_logger.LogDebug($"Getting Export Descriptors:"
+ $" contractName=[{contract.ContractName}]"
+ $" contractType=[{contract.ContractType.FullName}]");
}
var svc = _serviceProvider.GetService(contract.ContractType);
if (svc == null)
{
if (_logger.IsEnabled(LogLevel.Debug))
{
_logger.LogDebug($"No DI service found for"
+ $" contractType=[{contract.ContractType.FullName}]");
}
yield break;
}
if (_logger.IsEnabled(LogLevel.Debug))
{
_logger.LogDebug($"Resolved DI service for"
+ $" contractType=[{contract.ContractType.FullName}]"
+ $" service=[{svc}]");
}
CompositeActivator ca = (ctx, op) => svc;
yield return(new ExportDescriptorPromise(contract, ORIGIN_NAME, true,
NoDependencies, deps => ExportDescriptor.Create(ca, NoMetadata)));
}
public override CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activatorBody,
IDictionary<string, object> partMetadata,
IEnumerable<CompositionDependency> dependencies)
{
if (!ContractHelpers.IsShared(partMetadata))
return activatorBody;
object sharingBoundaryMetadata;
if (!partMetadata.TryGetValue(SharingBoundaryPartMetadataName, out sharingBoundaryMetadata))
sharingBoundaryMetadata = null;
var sharingBoundary = (string)sharingBoundaryMetadata;
var sharingKey = LifetimeContext.AllocateSharingId();
return (c, o) =>
{
var scope = c.FindContextWithin(sharingBoundary);
if (object.ReferenceEquals(scope, c))
return scope.GetOrCreate(sharingKey, o, activatorBody);
else
return CompositionOperation.Run(scope, (c1, o1) => c1.GetOrCreate(sharingKey, o1, activatorBody));
};
}
public override CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activatorBody,
IDictionary <string, object> partMetadata,
IEnumerable <CompositionDependency> dependencies)
{
if (!ContractHelpers.IsShared(partMetadata))
{
return(activatorBody);
}
object sharingBoundaryMetadata;
if (!partMetadata.TryGetValue(SharingBoundaryPartMetadataName, out sharingBoundaryMetadata))
{
sharingBoundaryMetadata = null;
}
var sharingBoundary = (string)sharingBoundaryMetadata;
var sharingKey = LifetimeContext.AllocateSharingId();
return((c, o) =>
{
var scope = c.FindContextWithin(sharingBoundary);
if (object.ReferenceEquals(scope, c))
{
return scope.GetOrCreate(sharingKey, o, activatorBody);
}
else
{
return CompositionOperation.Run(scope, (c1, o1) => c1.GetOrCreate(sharingKey, o1, activatorBody));
}
});
}
public void Create_Valid_ReturnsExpected(CompositeActivator activator, Dictionary <string, object> metadata)
{
ExportDescriptor descriptor = ExportDescriptor.Create(activator, metadata);
Assert.Same(activator, descriptor.Activator);
Assert.Same(metadata, descriptor.Metadata);
}
public DirectExportDescriptor(CompositeActivator activator, IDictionary<string, object> metadata)
{
Requires.NotNull(activator, "activator");
Requires.NotNull(metadata, "metadata");
_activator = activator;
_metadata = metadata;
}
public DirectExportDescriptor(CompositeActivator activator, IDictionary <string, object> metadata)
{
Requires.NotNull(activator, "activator");
Requires.NotNull(metadata, "metadata");
_activator = activator;
_metadata = metadata;
}
CompositeActivator CreateActivator(IEnumerable <CompositionDependency> dependencies)
{
var dependenciesByImport = dependencies.GroupBy(d => (ContractBasedImportDefinition)d.Site, d => d.Target.GetDescriptor());
var prereqs = dependenciesByImport.Where(d => d.Key.IsPrerequisite).ToArray();
var nonprereqs = dependenciesByImport.Where(d => !d.Key.IsPrerequisite).ToArray();
var unset = _part.ImportDefinitions.Where(id => !prereqs.Concat(nonprereqs).Any(k => k.Key.Equals((ContractBasedImportDefinition)id))).ToArray();
CompositeActivator construct = (c, o) =>
{
var result = _part.CreatePart();
if (result is IDisposable)
{
c.AddBoundInstance((IDisposable)result);
}
foreach (var pre in prereqs)
{
result.SetImport(pre.Key, DependenciesToExports(c, pre));
}
foreach (var un in unset)
{
result.SetImport(un, Enumerable.Empty <Export>());
}
o.AddNonPrerequisiteAction(() =>
{
foreach (var np in nonprereqs)
{
result.SetImport(np.Key, DependenciesToExports(c, np));
}
});
o.AddPostCompositionAction(() =>
{
result.Activate();
});
return(result);
};
if (!IsShared)
{
return(construct);
}
var sharingId = LifetimeContext.AllocateSharingId();
CompositeActivator constructAndShare = (c, o) => c.GetOrCreate(sharingId, o, construct);
return((c, o) =>
{
var scope = c.FindContextWithin(_boundary);
return scope.Equals(c) ?
constructAndShare(scope, o) :
CompositionOperation.Run(scope, constructAndShare);
});
}
public CompositeActivator GetActivator(IEnumerable <CompositionDependency> dependencies)
{
if (_activator == null)
{
_activator = CreateActivator(dependencies);
}
return(_activator);
}
public override CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activator,
IDictionary <string, object> partMetadata,
IEnumerable <CompositionDependency> dependencies)
{
var propertyDependencies = dependencies
.Where(dep => dep.Site is PropertyImportSite)
.ToDictionary(d => ((PropertyImportSite)d.Site).Property);
if (propertyDependencies.Count == 0)
{
return(activator);
}
var lc = Expression.Parameter(typeof(LifetimeContext));
var op = Expression.Parameter(typeof(CompositionOperation));
var inst = Expression.Parameter(typeof(object));
var typed = Expression.Variable(partType.AsType());
var statements = new List <Expression>();
var assignTyped = Expression.Assign(typed, Expression.Convert(inst, partType.AsType()));
statements.Add(assignTyped);
foreach (var d in propertyDependencies)
{
var property = d.Key;
var assignment = Expression.Assign(
Expression.MakeMemberAccess(typed, property),
Expression.Convert(
Expression.Call(
Expression.Constant(d.Value.Target.GetDescriptor().Activator),
ActivatorInvokeMethod,
lc,
op),
property.PropertyType));
statements.Add(assignment);
}
statements.Add(inst);
var setAll = Expression.Block(new[] { typed }, statements);
var setAction = Expression.Lambda <Func <object, LifetimeContext, CompositionOperation, object> >(
setAll, inst, lc, op).Compile();
return((c, o) =>
{
var i = activator(c, o);
o.AddNonPrerequisiteAction(() => setAction(i, c, o));
return i;
});
}
/// <summary>
/// Execute a new composition operation starting within the specified lifetime
/// context, for the specified activator.
/// </summary>
/// <param name="outermostLifetimeContext">Context in which to begin the operation (the operation can flow
/// to the parents of the context if requried).</param>
/// <param name="compositionRootActivator">Activator that will drive the operation.</param>
/// <returns>The composed object graph.</returns>
public static object Run(LifetimeContext outermostLifetimeContext, CompositeActivator compositionRootActivator)
{
Requires.ArgumentNotNull(outermostLifetimeContext, "outermostLifetimeContext");
Requires.ArgumentNotNull(compositionRootActivator, "compositionRootActivator");
using (var operation = new CompositionOperation())
{
var result = compositionRootActivator(outermostLifetimeContext, operation);
operation.Complete();
return(result);
}
}
/// <summary>
/// Execute a new composition operation starting within the specified lifetime
/// context, for the specified activator.
/// </summary>
/// <param name="outermostLifetimeContext">Context in which to begin the operation (the operation can flow
/// to the parents of the context if requried).</param>
/// <param name="compositionRootActivator">Activator that will drive the operation.</param>
/// <returns>The composed object graph.</returns>
public static object Run(LifetimeContext outermostLifetimeContext, CompositeActivator compositionRootActivator)
{
Requires.NotNull(outermostLifetimeContext, nameof(outermostLifetimeContext));
Requires.NotNull(compositionRootActivator, nameof(compositionRootActivator));
using (var operation = new CompositionOperation())
{
var result = compositionRootActivator(outermostLifetimeContext, operation);
operation.Complete();
return result;
}
}
protected override ExportDescriptor GetExportDescriptor(CompositeActivator partActivator)
{
var args = new[] { Expression.Parameter(typeof(LifetimeContext)), Expression.Parameter(typeof(CompositionOperation)) };
var activator = Expression.Lambda <CompositeActivator>(
Expression.Property(
Expression.Convert(Expression.Call(Expression.Constant(partActivator), ActivatorInvoke, args), _property.DeclaringType),
_property),
args);
return(ExportDescriptor.Create(activator.Compile(), Metadata));
}
protected override ExportDescriptor GetExportDescriptor(CompositeActivator partActivator)
{
var args = new[] { Expression.Parameter(typeof(LifetimeContext)), Expression.Parameter(typeof(CompositionOperation)) };
var activator = Expression.Lambda<CompositeActivator>(
Expression.Property(
Expression.Convert(Expression.Call(Expression.Constant(partActivator), s_activatorInvoke, args), _property.DeclaringType),
_property),
args);
return ExportDescriptor.Create(activator.Compile(), Metadata);
}
public override CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activator,
IDictionary<string, object> partMetadata,
IEnumerable<CompositionDependency> dependencies)
{
var propertyDependencies = dependencies
.Where(dep => dep.Site is PropertyImportSite)
.ToDictionary(d => ((PropertyImportSite)d.Site).Property);
if (propertyDependencies.Count == 0)
return activator;
var lc = Expression.Parameter(typeof(LifetimeContext));
var op = Expression.Parameter(typeof(CompositionOperation));
var inst = Expression.Parameter(typeof(object));
var typed = Expression.Variable(partType.AsType());
var statements = new List<Expression>();
var assignTyped = Expression.Assign(typed, Expression.Convert(inst, partType.AsType()));
statements.Add(assignTyped);
foreach (var d in propertyDependencies)
{
var property = d.Key;
var assignment = Expression.Assign(
Expression.MakeMemberAccess(typed, property),
Expression.Convert(
Expression.Call(
Expression.Constant(d.Value.Target.GetDescriptor().Activator),
s_activatorInvokeMethod,
lc,
op),
property.PropertyType));
statements.Add(assignment);
}
statements.Add(inst);
var setAll = Expression.Block(new[] { typed }, statements);
var setAction = Expression.Lambda<Func<object, LifetimeContext, CompositionOperation, object>>(
setAll, inst, lc, op).Compile();
return (c, o) =>
{
var i = activator(c, o);
o.AddNonPrerequisiteAction(() => setAction(i, c, o));
return i;
};
}
public DirectExportDescriptor(CompositeActivator activator, IDictionary <string, object> metadata)
{
if (activator == null)
{
throw new ArgumentNullException(nameof(activator));
}
if (metadata == null)
{
throw new ArgumentNullException(nameof(metadata));
}
_activator = activator;
_metadata = metadata;
}
public DelegateExportDescriptorProvider(Func <object> exportedInstanceFactory, Type contractType, string contractName, IDictionary <string, object> metadata, bool isShared)
: base(contractType, contractName, metadata)
{
if (exportedInstanceFactory == null)
{
throw new ArgumentNullException("exportedInstanceFactory");
}
// Runs the factory method, validates the result and registers it for disposal if necessary.
CompositeActivator constructor = (c, o) =>
{
var result = exportedInstanceFactory();
if (result == null)
{
throw new InvalidOperationException("Delegate factory returned null.");
}
if (result is IDisposable)
{
c.AddBoundInstance((IDisposable)result);
}
return(result);
};
if (isShared)
{
var sharingId = LifetimeContext.AllocateSharingId();
_activator = (c, o) =>
{
// Find the root composition scope.
var scope = c.FindContextWithin(null);
if (scope == c)
{
// We're already in the root scope, create the instance
return(scope.GetOrCreate(sharingId, o, constructor));
}
else
{
// Composition is moving up the hierarchy of scopes; run
// a new operation in the root scope.
return(CompositionOperation.Run(scope, (c1, o1) => c1.GetOrCreate(sharingId, o1, constructor)));
}
};
}
else
{
_activator = constructor;
}
}
public CompositeActivator GetActivator(DependencyAccessor definitionAccessor, IEnumerable <CompositionDependency> dependencies)
{
if (_partActivator != null)
{
return(_partActivator);
}
var contextParam = Expression.Parameter(typeof(LifetimeContext), "cc");
var operationParm = Expression.Parameter(typeof(CompositionOperation), "op");
var cps = _constructor.GetParameters();
Expression[] paramActivatorCalls = new Expression[cps.Length];
var partActivatorDependencies = dependencies
.Where(dep => dep.Site is ParameterImportSite)
.ToDictionary(d => ((ParameterImportSite)d.Site).Parameter);
for (var i = 0; i < cps.Length; ++i)
{
var pi = cps[i];
CompositionDependency dep;
if (partActivatorDependencies.TryGetValue(pi, out dep))
{
var a = dep.Target.GetDescriptor().Activator;
paramActivatorCalls[i] =
Expression.Convert(Expression.Call(Expression.Constant(a), s_activatorInvoke, contextParam, operationParm), pi.ParameterType);
}
else
{
paramActivatorCalls[i] = Expression.Default(pi.ParameterType);
}
}
Expression body = Expression.Convert(Expression.New(_constructor, paramActivatorCalls), typeof(object));
var activator = Expression
.Lambda <CompositeActivator>(body, contextParam, operationParm)
.Compile();
foreach (var activationFeature in _activationFeatures)
{
activator = activationFeature.RewriteActivator(_partType, activator, _partMetadata.Value, dependencies);
}
_partActivator = activator;
return(_partActivator);
}
public override CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activator,
IDictionary<string, object> partMetadata,
IEnumerable<CompositionDependency> dependencies)
{
if (!typeof(IDisposable).GetTypeInfo().IsAssignableFrom(partType))
return activator;
return (c, o) =>
{
var inst = (IDisposable)activator(c, o);
c.AddBoundInstance(inst);
return inst;
};
}
public ExportDescriptorPromise GetPromise(CompositionContract contract, DependencyAccessor descriptorAccessor)
{
var origin = _export.ToString();
if (_export is ICompositionElement)
{
origin = ((ICompositionElement)_export).DisplayName;
}
return(new ExportDescriptorPromise(contract, origin, _part.IsShared, () => _part.GetDependencies(descriptorAccessor), d =>
{
var partActivator = _part.GetActivator(d);
CompositeActivator exportActivator = (c, o) => ((ComposablePart)partActivator(c, o)).GetExportedValue(_export);
return ExportDescriptor.Create(exportActivator, _export.Metadata);
}));
}
public override CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activator,
IDictionary <string, object> partMetadata,
IEnumerable <CompositionDependency> dependencies)
{
if (!typeof(IDisposable).GetTypeInfo().IsAssignableFrom(partType))
{
return(activator);
}
return((c, o) =>
{
var inst = (IDisposable)activator(c, o);
c.AddBoundInstance(inst);
return inst;
});
}
/// <summary>
/// Execute a new composition operation starting within the specified lifetime
/// context, for the specified activator.
/// </summary>
/// <param name="outermostLifetimeContext">Context in which to begin the operation (the operation can flow
/// to the parents of the context if required).</param>
/// <param name="compositionRootActivator">Activator that will drive the operation.</param>
/// <returns>The composed object graph.</returns>
public static object Run(LifetimeContext outermostLifetimeContext, CompositeActivator compositionRootActivator)
{
if (outermostLifetimeContext is null)
{
throw new ArgumentNullException(nameof(outermostLifetimeContext));
}
if (compositionRootActivator is null)
{
throw new ArgumentNullException(nameof(compositionRootActivator));
}
using (var operation = new CompositionOperation())
{
var result = compositionRootActivator(outermostLifetimeContext, operation);
operation.Complete();
return(result);
}
}
public void GetDescriptor_CycleActivatorNotCompleted_ThrowsNotImplementedException()
{
ExportDescriptorPromise promise = null;
promise = new ExportDescriptorPromise(new CompositionContract(typeof(int)), "Origin", true, () => Enumerable.Empty <CompositionDependency>(), depdendencies =>
{
ExportDescriptor cycleDescriptor = promise.GetDescriptor();
CompositeActivator activator = cycleDescriptor.Activator;
Assert.Throws <NotImplementedException>(() => activator(null, null));
return(ExportDescriptor.Create(Activator, new Dictionary <string, object> {
{ "key", "value" }
}));
});
// Invoke the GetDescriptor method to start the test.
Assert.NotNull(promise.GetDescriptor());
}
public void GetDescriptor_CycleActivatorNotCompleted_ThrowsInternalErrorException()
{
ExportDescriptorPromise promise = null;
promise = new ExportDescriptorPromise(new CompositionContract(typeof(int)), "Origin", true, () => Enumerable.Empty <CompositionDependency>(), depdendencies =>
{
ExportDescriptor cycleDescriptor = promise.GetDescriptor();
CompositeActivator activator = cycleDescriptor.Activator;
Exception ex = Assert.ThrowsAny <Exception>(() => activator(null, null));
Assert.Equal("Microsoft.Internal.Assumes+InternalErrorException", ex.GetType().ToString());
return(ExportDescriptor.Create(Activator, new Dictionary <string, object> {
{ "key", "value" }
}));
});
// Invoke the GetDescriptor method to start the test.
Assert.NotNull(promise.GetDescriptor());
}
public DelegateExportDescriptorProvider(Func<object> exportedInstanceFactory, Type contractType, string contractName, IDictionary<string, object> metadata, bool isShared)
: base (contractType, contractName, metadata)
{
if (exportedInstanceFactory == null) throw new ArgumentNullException("exportedInstanceFactory");
Contract.EndContractBlock();
// Runs the factory method, validates the result and registers it for disposal if necessary.
CompositeActivator constructor = (c, o) => {
var result = exportedInstanceFactory();
if (result == null)
throw new InvalidOperationException("Delegate factory returned null.");
if (result is IDisposable)
c.AddBoundInstance((IDisposable)result);
return result;
};
if (isShared)
{
var sharingId = LifetimeContext.AllocateSharingId();
_activator = (c, o) => {
// Find the root composition scope.
var scope = c.FindContextWithin(null);
if (scope == c)
{
// We're already in the root scope, create the instance
return scope.GetOrCreate(sharingId, o, constructor);
}
else
{
// Composition is moving up the hierarchy of scopes; run
// a new operation in the root scope.
return CompositionOperation.Run(scope, (c1, o1) => c1.GetOrCreate(sharingId, o1, constructor));
}
};
}
else
{
_activator = constructor;
}
}
public void GetDescriptor_CycleActivatorCompleted_Success()
{
ExportDescriptorPromise promise = null;
CompositeActivator activator = null;
promise = new ExportDescriptorPromise(new CompositionContract(typeof(int)), "Origin", true, () => Enumerable.Empty <CompositionDependency>(), depdendencies =>
{
ExportDescriptor cycleDescriptor = promise.GetDescriptor();
activator = cycleDescriptor.Activator;
return(ExportDescriptor.Create(Activator, new Dictionary <string, object> {
{ "key", "value" }
}));
});
ExportDescriptor descriptor = promise.GetDescriptor();
Assert.Equal("hi", descriptor.Activator(null, null));
Assert.Equal("hi", activator(null, null));
}
/// <summary>
/// Either retrieve an existing part instance with the specified sharing id, or
/// create and share a new part instance using <paramref name="creator"/> within
/// <paramref name="operation"/>.
/// </summary>
/// <param name="sharingId">Sharing id for the part in question.</param>
/// <param name="operation">Operation in which to activate a new part instance if necessary.</param>
/// <param name="creator">Activator that can activate a new part instance if necessary.</param>
/// <returns>The part instance corresponding to <paramref name="sharingId"/> within this lifetime context.</returns>
/// <remarks>This method is lock-free if the part instance already exists. If the part instance must be created,
/// a lock will be taken that will serialize other writes via this method (concurrent reads will continue to
/// be safe and lock-free). It is important that the composition, and thus lock acquisition, is strictly
/// leaf-to-root in the lifetime tree.</remarks>
public object GetOrCreate(int sharingId, CompositionOperation operation, CompositeActivator creator)
{
object result;
if (_sharedPartInstances != null && _sharedPartInstances.TryGetValue(sharingId, out result))
{
return(result);
}
// Remains locked for the rest of the operation.
operation.EnterSharingLock(_sharingLock);
if (_sharedPartInstances == null)
{
_sharedPartInstances = new SmallSparseInitonlyArray();
_instancesUndergoingInitialization = new SmallSparseInitonlyArray();
}
else if (_sharedPartInstances.TryGetValue(sharingId, out result))
{
return(result);
}
// Already being initialized _on the same thread_.
if (_instancesUndergoingInitialization.TryGetValue(sharingId, out result))
{
return(result);
}
result = creator(this, operation);
_instancesUndergoingInitialization.Add(sharingId, result);
operation.AddPostCompositionAction(() =>
{
_sharedPartInstances.Add(sharingId, result);
});
return(result);
}
public override CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activator,
IDictionary <string, object> partMetadata,
IEnumerable <CompositionDependency> dependencies)
{
var result = activator;
var partTypeAsType = partType.AsType();
var importsSatisfiedMethods = partTypeAsType.GetRuntimeMethods()
.Where(mi => _attributeContext.GetDeclaredAttribute <OnImportsSatisfiedAttribute>(mi.DeclaringType, mi) != null);
foreach (var m in importsSatisfiedMethods)
{
if (!(m.IsPublic || m.IsAssembly) | m.IsStatic || m.ReturnType != typeof(void) ||
m.IsGenericMethodDefinition || m.GetParameters().Length != 0)
{
var message = string.Format(
Properties.Resources.OnImportsSatisfiedFeature_AttributeError,
partType, m.Name);
throw new CompositionFailedException(message);
}
var ois = Expression.Parameter(typeof(object), "ois");
var call = Expression.Lambda <Action <object> >(
Expression.Call(Expression.Convert(ois, partType.AsType()), m), ois).Compile();
var prev = result;
result = (c, o) =>
{
var psn = prev(c, o);
o.AddPostCompositionAction(() => call(psn));
return(psn);
};
}
return(result);
}
public override CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activator,
IDictionary<string, object> partMetadata,
IEnumerable<CompositionDependency> dependencies)
{
var result = activator;
var partTypeAsType = partType.AsType();
var importsSatisfiedMethods = partTypeAsType.GetRuntimeMethods()
.Where(mi => _attributeContext.GetDeclaredAttribute<OnImportsSatisfiedAttribute>(mi.DeclaringType, mi) != null);
foreach (var m in importsSatisfiedMethods)
{
if (!(m.IsPublic || m.IsAssembly) | m.IsStatic || m.ReturnType != typeof(void) ||
m.IsGenericMethodDefinition || m.GetParameters().Length != 0)
{
var message = string.Format(
Properties.Resources.OnImportsSatisfiedFeature_AttributeError,
partType, m.Name);
throw new CompositionFailedException(message);
}
var ois = Expression.Parameter(typeof(object), "ois");
var call = Expression.Lambda<Action<object>>(
Expression.Call(Expression.Convert(ois, partType.AsType()), m), ois).Compile();
var prev = result;
result = (c, o) =>
{
var psn = prev(c, o);
o.AddPostCompositionAction(() => call(psn));
return psn;
};
}
return result;
}
/// <summary>
/// Either retrieve an existing part instance with the specified sharing id, or
/// create and share a new part instance using <paramref name="creator"/> within
/// <paramref name="operation"/>.
/// </summary>
/// <param name="sharingId">Sharing id for the part in question.</param>
/// <param name="operation">Operation in which to activate a new part instance if necessary.</param>
/// <param name="creator">Activator that can activate a new part instance if necessary.</param>
/// <returns>The part instance corresponding to <paramref name="sharingId"/> within this lifetime context.</returns>
/// <remarks>This method is lock-free if the part instance already exists. If the part instance must be created,
/// a lock will be taken that will serialize other writes via this method (concurrent reads will continue to
/// be safe and lock-free). It is important that the composition, and thus lock acquisition, is strictly
/// leaf-to-root in the lifetime tree.</remarks>
public object GetOrCreate(int sharingId, CompositionOperation operation, CompositeActivator creator)
{
object result;
if (_sharedPartInstances != null && _sharedPartInstances.TryGetValue(sharingId, out result))
return result;
// Remains locked for the rest of the operation.
operation.EnterSharingLock(_sharingLock);
if (_sharedPartInstances == null)
{
_sharedPartInstances = new SmallSparseInitonlyArray();
_instancesUndergoingInitialization = new SmallSparseInitonlyArray();
}
else if (_sharedPartInstances.TryGetValue(sharingId, out result))
{
return result;
}
// Already being initialized _on the same thread_.
if (_instancesUndergoingInitialization.TryGetValue(sharingId, out result))
return result;
result = creator(this, operation);
_instancesUndergoingInitialization.Add(sharingId, result);
operation.AddPostCompositionAction(() =>
{
_sharedPartInstances.Add(sharingId, result);
});
return result;
}
public DirectExportDescriptor(CompositeActivator activator !!, IDictionary <string, object> metadata !!)
public object GetOrCreate(int sharingId, CompositionOperation operation, CompositeActivator creator);
public static ExportDescriptor Create(CompositeActivator activator, IDictionary<string, object> metadata);
public static object Run(LifetimeContext outermostLifetimeContext, CompositeActivator compositionRootActivator);
protected abstract ExportDescriptor GetExportDescriptor(CompositeActivator partActivator);
/// <summary>
/// Construct an <see cref="ExportDescriptor"/>.
/// </summary>
/// <param name="activator">The activator used to retrieve instances of the export.</param>
/// <param name="metadata">The Export Metadata associated with the export.</param>
/// <returns>The export descriptor.</returns>
public static ExportDescriptor Create(CompositeActivator activator, IDictionary <string, object> metadata)
{
return(new DirectExportDescriptor(activator, metadata));
}
protected override ExportDescriptor GetExportDescriptor(CompositeActivator partActivator)
{
return ExportDescriptor.Create(partActivator, Metadata);
}
protected override ExportDescriptor GetExportDescriptor(CompositeActivator partActivator)
{
return(ExportDescriptor.Create(partActivator, Metadata));
}
protected abstract ExportDescriptor GetExportDescriptor(CompositeActivator partActivator);
/// <summary>
/// Construct an <see cref="ExportDescriptor"/>.
/// </summary>
/// <param name="activator">The activator used to retrieve instances of the export.</param>
/// <param name="metadata">The Export Metadata associated with the export.</param>
/// <returns>The export descriptor.</returns>
public static ExportDescriptor Create(CompositeActivator activator, IDictionary<string, object> metadata)
{
return new DirectExportDescriptor(activator, metadata);
}
/// <summary>
/// Participate in the activator creation process.
/// </summary>
/// <param name="partType">The part type being activated.</param>
/// <param name="activator">The activator body so far.</param>
/// <param name="partMetadata">Metadata associated with the part being activated.</param>
/// <param name="dependencies">Dependencies returned by a previous call to <see cref="GetDependencies"/>.</param>
/// <returns>A new activator body, or the one already provided.</returns>
public abstract CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activator,
IDictionary<string, object> partMetadata,
IEnumerable<CompositionDependency> dependencies);
public CompositeActivator GetActivator(DependencyAccessor definitionAccessor, IEnumerable<CompositionDependency> dependencies)
{
if (_partActivator != null) return _partActivator;
var contextParam = Expression.Parameter(typeof(LifetimeContext), "cc");
var operationParm = Expression.Parameter(typeof(CompositionOperation), "op");
var cps = _constructor.GetParameters();
Expression[] paramActivatorCalls = new Expression[cps.Length];
var partActivatorDependencies = dependencies
.Where(dep => dep.Site is ParameterImportSite)
.ToDictionary(d => ((ParameterImportSite)d.Site).Parameter);
for (var i = 0; i < cps.Length; ++i)
{
var pi = cps[i];
CompositionDependency dep;
if (partActivatorDependencies.TryGetValue(pi, out dep))
{
var a = dep.Target.GetDescriptor().Activator;
paramActivatorCalls[i] =
Expression.Convert(Expression.Call(Expression.Constant(a), s_activatorInvoke, contextParam, operationParm), pi.ParameterType);
}
else
{
paramActivatorCalls[i] = Expression.Default(pi.ParameterType);
}
}
Expression body = Expression.Convert(Expression.New(_constructor, paramActivatorCalls), typeof(object));
var activator = Expression
.Lambda<CompositeActivator>(body, contextParam, operationParm)
.Compile();
foreach (var activationFeature in _activationFeatures)
activator = activationFeature.RewriteActivator(_partType, activator, _partMetadata.Value, dependencies);
_partActivator = activator;
return _partActivator;
}
// The source will only be asked for parts once per exportKey, but it is the
// source's responsibility to return the same part multiple times when that part
// has more than one export (not shown here.)
//
public override IEnumerable <ExportDescriptorPromise> GetExportDescriptors(CompositionContract contract, DependencyAccessor definitionAccessor)
{
if (contract.Equals(new CompositionContract(typeof(RequestListener))))
{
return new[] { RequestListenerPart(contract, definitionAccessor) }
}
;
if (contract.Equals(new CompositionContract(typeof(ConsoleLog))))
{
return new[] { ConsoleLogPart(contract, definitionAccessor) }
}
;
return(NoExportDescriptors);
}
// Console log is a disposable singleton (no boundaries)
// that exports itself under its own concrete type.
//
ExportDescriptorPromise ConsoleLogPart(CompositionContract contract, DependencyAccessor definitionAccessor)
{
return(new ExportDescriptorPromise(
contract,
typeof(ConsoleLog).Name,
true,
NoDependencies,
_ =>
{
var sharingId = LifetimeContext.AllocateSharingId();
return ExportDescriptor.Create((c, o) =>
{
CompositeActivator activatorBody = (sc, so) =>
{
var result = new ConsoleLog();
c.AddBoundInstance(result);
return result;
};
var scope = c.FindContextWithin(null);
if (object.ReferenceEquals(scope, c))
{
return scope.GetOrCreate(sharingId, o, activatorBody);
}
else
{
return CompositionOperation.Run(scope, (c1, o1) => c1.GetOrCreate(sharingId, o1, activatorBody));
}
}, NoMetadata);
}));
}
// Non-shared part that exports itself and has a dependency on ConsoleLog.
//
ExportDescriptorPromise RequestListenerPart(CompositionContract contract, DependencyAccessor definitionAccessor)
{
return(new ExportDescriptorPromise(
contract,
typeof(RequestListener).Name,
false,
() => new[] { definitionAccessor.ResolveRequiredDependency("log", new CompositionContract(typeof(Lazy <ConsoleLog>)), true) },
dependencies =>
{
var logActivator = dependencies.Single().Target.GetDescriptor().Activator;
return ExportDescriptor.Create((c, o) =>
{
var log = (Lazy <ConsoleLog>)logActivator(c, o);
return new RequestListener(log);
}, NoMetadata);
}));
}
}
}
/// <summary>
/// Participate in the activator creation process.
/// </summary>
/// <param name="partType">The part type being activated.</param>
/// <param name="activator">The activator body so far.</param>
/// <param name="partMetadata">Metadata associated with the part being activated.</param>
/// <param name="dependencies">Dependencies returned by a previous call to <see cref="GetDependencies"/>.</param>
/// <returns>A new activator body, or the one already provided.</returns>
public abstract CompositeActivator RewriteActivator(
TypeInfo partType,
CompositeActivator activator,
IDictionary <string, object> partMetadata,
IEnumerable <CompositionDependency> dependencies);